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general description the MAX77829 is a high-performance companion pmic for latest 3g/4g smartphones and tablets. the pmic includes a single-input 2.0a switched-mode charger with reverse-boost capability and adapter input protection up to 22v (dc) for one-cell lithium-ion (li+) battery, a safeout ldo, and wled backlight driver supporting up to 25ma/string, 35v output voltage. it also features a dual- channel 1.5a (combined, 750ma/ch) flash led driver (with torch mode included). the typical 4mhz switched-mode battery charger with two integrated switches, providing the smallest l/c size, lowest heat and fastest programmable battery-charging current, is ideally suited for portable devices such as headsets and ultra-portable media players. the char - ger features single input, which works for adapter/usb type inputs. all the MAX77829 blocks connecting to the adapter/usb pin are protected from input overvoltage events. the dc pin is rated to 22v absolute maximum. the usb-otg output provides true-load disconnect and is protected by an adjustable output current limit (default 900ma, other current limit is also available with different factory setting up to 900ma). the battery charger drives an external p-channel mosfet as power-path switch, and its i 2 c-programmable settings can accommodate a wide range of battery sizes and system loads. when configured in reverse boost mode, the MAX77829 requires no additional inductor to power usb otg accessories and/or provide illumination to the flash led. the switching charger implements a special cc, cv, and die temperature regulation algorithm; the patented maxflash prevents overloading a weak battery, further extending battery life. the MAX77829 features an i 2 c 2.0-compatible serial interface consisting of a bidirectional serial data line (sda) and a serial clock line (scl). beneits and features highly integrated solution ? single input switched mode charger ? camera flash and torch led driver, dual-channel 750ma/ch ? two-string white led backlight driver, 25ma/ch, 35v ovp ? one safeout ldo single high efficient switched mode charger ? supporting up to 2.0a charging current capability ? input-voltage-based automatic input current limit (aicl) power management ? system voltage regulator/battery charger with external power path ? various charging protection features single input accommodating standard usb and high input voltage adaptor ? 22v absolute maximum input voltage rating, ? up to +9.4v maximum operating input voltage usb otg capability ? reverse boost support, up to 900ma at +5v ? programmable reverse boost output voltage (up to 5.8v) flexible programmability ? i 2 c 2.0 serial interface compact package ? 3.64mm x 3.24mm wlp, 8 x 7 array, 56-bumps, 0.4mm pitch applications smartphone and tablets other li-ion battery power handheld devices ordering information appears at end of data sheet. 19-8316; rev 0; 12/15 MAX77829 companion pmic for smartphone and tablet evaluation kit available downloaded from: http:///
dc, byp to gnd ................................................... -0.3v to +22v lx, bst to gnd .................................................... -0.3v to +12v cs, syss, sys, avl, pvl, fet_drv, mbatt, in_fled, chgind to gnd ................... -0.3v to +6v mbatsnsp, mbatsnsn, mbatdet, thm to gnd ........................................................ -0.3v to +6v inok to gnd .......................................... -0.3v to (v sys + 0.3v) lx, chgpg continuous current ..................................... 2a rms dc, byp continuous current ........................................... 2a rms fled to gnd ......................................... -0.3v to (v byp + 0.3v) torchen, flashen to gnd ........... -0.3v to (v sys_a + 0.3v) fled1, fled2 current ................................................. 0.8a rms safeout to gnd ................................... -0.3v to (v dc + 0.3v) safeout continuous current ........................................ 100ma wledout, wled1, wled2 to gnd .................. -0.3v to +36v wledgnd, wledpgnd to gnd ........................ -0.3v to 0.3v wledpwm to gnd ............................... -0.3v to (v sys + 0.3v) wledlx continuous current ....................................... 1.2a rms vio to gnd ............................................................. -0.3v to +6v sda, scl to gnd ................................... -0.3v to (v vio + 0.3v) mrst, reset, int to gnd ................ -0.3v to (v sys_a + 0.3v) test_, vcctest, sys_ to gnd .......................... -0.3v to +6v gnd_ to gnd ...................................................... -0.3v to +0.3v continuous power dissipation (t a = +70c) wlp (derate 25mw/c above 70c) ......................... 2000mw operating temperature ...................................... -40c to +85c junction temperature ...................................................... +150c storage temperature range ............................ -65c to +150c soldering temperature (reflow) ....................................... +260c wlp junction-to-ambient thermal resistance ( ja ) .......... 40c/w (note 1) (v dc = 5v, c byp = 2.2f, c pvl = c avl = 10f, c sys = 10f, c mbat = 4.7f, t a = -40c to +85c, unless otherwise noted. typical values are at t a = +25c.) (note 2) MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 2 note 1: package thermal resistances were obtained using the method described in jedec specification jesd51-7, using a four-layer board. for detailed information on package thermal considerations, refer to www.maximintegrated.com/thermal-tutorial . absolute maximum ratings stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. these are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. package thermal characteristics parameter symbol conditions min typ max units dc input dc operating voltage range 3.5 v ovlo (min) v dc startup voltage range 4.0 v ovlo v dc undervoltage lockout v uvlo dc rising, 500mv hysteresis 3.6 3.8 4.0 v dc overvoltage lockout v ovlo dc rising, 3% hysteresis, contact factory for alternate thresholds (5.9v, 7.5v, 9.7v) 6.3 6.5 6.7 v dc_v threshold v dc_v dc rising, 200mv hysteresis 5.7 5.8 5.95 v dc overvoltage interrupt delay 16 ms dc insertion debounce time t dbdc 100 120 150 ms dc to sys shutdown threshold when charging stops, v dc falling, 150mv hysteresis 0 50 100 mv electrical characteristics downloaded from: http:///
(v dc = 5v, c byp = 2.2f, c pvl = c avl = 10f, c sys = 10f, c mbat = 4.7f, t a = -40c to +85c, unless otherwise noted. typical values are at t a = +25c.) (note 2) MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 3 electrical characteristics (continued) parameter symbol conditions min typ max units dc supply current i dc usb suspend, v dc = 5.5v 0.5 ma charger enabled, f = 4mhz, v dc = 5.5v, v sysmin = 3.55v, qbat off, no load 2 dc current limit i dc_ilim programmed dcilmt[5:0], minimum 0.1 a programmed dcilmt[5:0], typical 2 input current limit accurancy usb 100ma mode 90 95 100 ma usb 500ma mode 450 475 500 programmed to 1.5a 1350 1500 1650 adaptive input current limit (aicl) voltage threshold v dc_aicl dc voltage where charging current is regulated, programmable from 4.0v to 4.6v in 100mv increments (4.5v setting) 4.410 4.5 4.635 v dc voltage where the charging current is reset to its minimum value (75ma), aicl_reset=0 v dc_aicl - 0.1 v input limit switch v dc = 5.5v, i byp = 100ma 50 100 m? leakage current bst leakage current v bst = v lxchg = 5.5v, v dc = v pgchg , v sys = 3.7v t a = +25c 0.01 10 a t a = -40c to +85c 0.1 mbatt reverse-leakage current v mbat = 4.2v, v dc = 0v t a = +25c 0.01 10 a t a = -40c to +85c 0.1 buck converter operation switching frequency v mbat = 3.7v 4 mhz max duty cycle 99.5 % minimum on-time 35 ns maximum on-time 10 s minimum off-time 35 ns soft-start time 1.5 ms high-side resistance i lx = 100ma, v dc = 5.5v 130 250 m? low-side resistance i lx = 100ma, v dc = 5.5v 150 220 m? thermal regulation temperature programmable-2 bits, see the regtemp[1:0] minimum 75 oc maximum 120 step size 15 battery charger pre-charge lower threshold v pqlth v mbatt rising, 125mv hysteresis, contact the factory for alternative selection for 2.1v, 2.2v, 2.3v, 2.4v, 2.5v, 2.6v, 2.7v, 2.8v 2.1 v dead-battery charge current i pqlth 0v v mbat v pqlth 40 ma downloaded from: http:///
(v dc = 5v, c byp = 2.2f, c pvl = c avl = 10f, c sys = 10f, c mbat = 4.7f, t a = -40c to +85c, unless otherwise noted. typical values are at t a = +25c.) (note 2) MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 4 electrical characteristics (continued) parameter symbol conditions min typ max units precharge upper threshold v pquth v mbat rising, 150mv hysteresis, contact the factory for alternative settings 3.4 v precharge current i prechg contact factory for alternative settings, 100ma, 200ma, 300ma, 400ma) with 200ma as default setting 200 ma constant current mode batt fast-charge current range i fchg programmable 50ma steps, rcs = 47m? minimum 250 ma maximum 2000 fast-charge current accuracy (voltage across r cs ) 11.5mv < v rcs < 70.5mv r cs = 47m?, v rcs = r cs x i chg t a = +10c to +45c -5 +5 % jeita safety region -65 -50 -35 constant voltage mode battery regulation voltage range programmable with mbatreg[3:0] minimum 3.55 v maximum 4.4 battery regulation voltage accuracy v mbatt when the charger is regulating battery voltage (i.e. top-off mode or fast- charger constant voltage mode), then it will regulate based on mbatreg[3:0]. charger is regulating battery voltage , v mbatreg = 4.2v (mbatreg[3:0]=0b1011), v mbatreg = 4.35v (mbatreg[3:0]=0b1111) t a = +25oc -0.5 +0.5 % t a = -40oc to +85oc -1 +1 when jeita is enabled (jeita_ en=1) and the battery temperature is in the cool region, the battery regulation voltage will be this much lower than the value programmed by mbatreg[3:0]. 150 mv battery refresh threshold v mbatreg = 4.2v (mbatreg[3:0]=0b1011), v mbatreg = 4.35v (mbatreg[3:0]=0b1111) after the charger enters the done state, it will restart when the battery falls this percentage below v mbatreg (mbatreg[3:0]) chgrstrt = 0 1 3 5 % chgrstrt = 1 2 4 6 battery overvoltage protection v mbat_ ovp v mbatreg = 4.2v (mbatreg[3:0]=0b1011), v mbatreg = 4.35v (mbatreg[3:0]=0b1111) vmbatt threshold over regulation voltage, hysteresis 2.2% (v bat falling) 102 104 106 % downloaded from: http:///
(v dc = 5v, c byp = 2.2f, c pvl = c avl = 10f, c sys = 10f, c mbat = 4.7f, t a = -40c to +85c, unless otherwise noted. typical values are at t a = +25c.) (note 2) MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 5 electrical characteristics (continued) parameter symbol conditions min typ max units charge current termination threshold range i done i 2 c programmable, see i topoff [2:0]. i done current independent of jeita functionality minimum 50 ma maximum 400 step size 50 charge current termination deglitch time 2mv overdrive 16 ms charge current termination accuracy i done = 200ma 180 224 ma i done = 50ma 35 70 vichg vichg output voltage v ichg_gain = 0, 1.41mv/ma i out = 50ma 70.5 mv i out = 1000ma 1260 1410 1540 i out = 1500ma 2150 charger timerdead-battery and precharge time t prechg usb 500ma mode (t prechg_500 ) 14 16 min usb 100ma mode (t prechg_100 ) 39 45 fast-charge time range t fchg i 2 c programmable, refer to fchgtime[2:0] for detailed values minimum 4 hour maximum 16 fast-charge timer accuracy default 5 hours setting 5 6 hour top-off time t topoff i 2 c programmable (see the t opofft [2:0]) minimum 0 min maximum 60 step size 10 top-off timer accuracy default 30 minute setting 20 % timer extend current threshold percentage of fast-charge current below which the timer clock operates at half-speed (when jeita is enabled) 50 % reverse boost byp reverse boost voltage adjustment range programmable with rbout[3:0], 2.6v < v sys < v byp - 0.5v minimum 3.0 v maximum 5.8 step size 0.025 reverse boost quiescent current switching 2.1 ma reverse boost voltage accuracy 5.1v setting, 0ma < i load < 500ma 4.94 5.1 5.36 v reverse boost converter maximum output current v sys = 3.7v(minimum required sys voltage to guarantee the boost output current) 1500 ma downloaded from: http:///
(v dc = 5v, c byp = 2.2f, c pvl = c avl = 10f, c sys = 10f, c mbat = 4.7f, t a = -40c to +85c, unless otherwise noted. typical values are at t a = +25c.) (note 2) MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 6 electrical characteristics (continued) parameter symbol conditions min typ max units reverse boost output voltage ripple discontinuous inductor current (i.e. skip mode) 50 mv v bat = 3.6v, v byp = 5.5v, i byp = 100ma 50 mv dc output capacitor device included 22 f maximum dc output current v sys = 3.7v 900 ma dc output current limit otgilim 1000 1970 ma otgilim interrupt debounce 30 ms reverse boost output voltage ripple when dc output current hits otgilim retry on-time 0.5 ms retry off-time 330 inductor peak current limit 3.49 3.9 4.40 a byp_uvlo falling 4.30 4.35 4.45 v byp_uvlo hysteresis 150 mv bat-sys-fet driver fet_drv output high i source = -1ma v pvl - 0.2 v fet_drv output low i sink = 1ma 0.2 v minimum v sys regulation voltage range v sysmin programmable with v sysreg [2:0] minimum 3.0 v maximum 3.6 step size 0.1 mbatt to sys fet turn-on threshold turn-on threshold (v mbatt rising) v pquth v turn-off threshold (v mbatt falling) v pquth - 0.15 v supplement mode threshold level entering supplement mode when v sys < v bat 25 40 50 mv exiting supplement mode 10 mv battery overcurrent threshold battery overcurrent threshold alarm r batrsns = 5m?, bat2soc[1:0] = 4.0a setting, overcurrent from bat to sys sensed through the 5m? resistor, it does not shut off external fet, but provides an overcurrent interrupt through bat_i to the processor 16 20 24 mv battery overcurrent debounce time 4ms setting (programmable from 4ms to 10ms) 3.8 4.0 4.2 ms downloaded from: http:///
(v dc = 5v, c byp = 2.2f, c pvl = c avl = 10f, c sys = 10f, c mbat = 4.7f, t a = -40c to +85c, unless otherwise noted. typical values are at t a = +25c.) (note 2) MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 7 electrical characteristics (continued) parameter symbol conditions min typ max units battery detection low-cost battery presence detection voltage v ini2c = 1.8v, v mbatdet rising, 60mv hysteresis 1.063 1.1 1.136 v 59.1 61.1 63.1 % v ini2c high-cost battery presence detection voltage v ini2c = 1.8v, v mbatdet rising, 20mv hysteresis 1.454 1.5 1.536 v turn off threshold (v mbatt falling) 80.8 83.3 85.3 % v ini2c battery disconnect detection voltage v ini2c = 1.8v, v mbatdet rising, 60mv hysteresis 1.621 1.65 1.676 v turn-off threshold (v mbatt falling) 90.1 91.6 93.1 % v ini2c battery detection debounce timer (bat_ removed) programmable with tdeb_batrem[4:0] minimum 0 s maximum 976 step size 30.5 strong pullup resistor strongpuenb=0 2.4 4.7 9.4 k mbatdet leakage current v ini2c = 5.5v, v mbatdet = 0v t a = +25c -1 0.01 +1 a v ini2c = 5.5v, v mbatdet = 0v t a = +85c 0.1 thermistor monitor (thresholds are calculated for r25 = 100k? and = 4050k) thm threshold, cold, no charge (-7c) t1 v thm /v avl rising, 2% hysteresis (thermistor temperature falling) 75.4 77.9 80.4 % thm cool threshold (10c) t2 v thm /v avl rising, 2% hysteresis (thermistor temperature falling), disabled through jeita_en register 61.5 64 66.5 % thm warm threshold (45c) t3 v thm /v avl falling, 2% hysteresis (thermistor temperature rising) , disabled through jeita_en register 30.47 32.97 35.47 % thm threshold, hot, no charge (56c) t4 v thm /v avl falling, 2% hysteresis (thermistor temperature rising) 23.1 25.6 28.1 % thm leakage current v thm = v avl or 0v t a = +25c -0.2 +0.01 +0.2 a t a = +85c 0.1 downloaded from: http:///
(v dc = 5v, c byp = 2.2f, c pvl = c avl = 10f, c sys = 10f, c mbat = 4.7f, t a = -40c to +85c, unless otherwise noted. typical values are at t a = +25c.) (note 2) (v sys = 3.7v, t a = -40c to +85c, unless otherwise noted. typical values are at t a = +25c.) (note 2) MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 8 electrical characteristics (continued) parameter symbol conditions min typ max units pvl/avl outputs dropout voltage v do v sys = 3.6v, i avl = 30ma, v do = v byp - v avl v dc = 4.5v 50 mv v dc = 0v 18 current limit 400 ma maximum output current i avlmax 100 ma avl/pvl pok output threshold threshold where internal power rails to charger turns on 2.7 v avl/pvl regulated output i avl = 0v to i pvlmax , v dc = 5.5v 4.75 5.00 5.25 v inok output low voltage i sink = 1ma 0.4 v output high leakage v sys = 5.5v t a = +25c -1 0 +1 a t a = +85c 0.1 chgind output low voltage i sink = 10ma 0.4 v output high leakage v sys = 5.5v t a = +25c -1 0 +1 a t a = +85c 0.1 thermal shutdown thermal shutdown temperature 160 c thermal shutdown hysteresis 15 c byp to in_fled switch in_fled switch resistance v byp = 5.0v, loading = 150ma 160 320 m parameter symbol conditions min typ max units flash dc-dc step-up converter (shared with switch mode charger) adaptive control range v in_fled adaptive controlled 3.3 5.5 v adaptive output voltage regulation threshold v in_fled-vfled_ , i fled_ = 750ma 250 mv adaptive regulation step size smallest step that the output will regulate to 25 mv led flash driver ec characteristics downloaded from: http:///
(v sys = 3.7v, t a = -40c to +85c, unless otherwise noted. typical values are at t a = +25c.) (note 2) MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 9 parameter symbol conditions min typ max units fled current regulator in_fled supply current 1.1 ma current setting for fled_ (i.e., fled1 or fled2) current range in flash mode in 23.436ma/step, powered from in_fled (fled1num=0) 23.436 750 ma current range in torch mode in 23.436ma/step 23.436 375 current accuracy 93ma setting; v byp = 5v; v fled_ = 4.2v t a = +25c -2.5 +2.5 % t a = -40c to +85c -4.5 +6.5 current regulator dropout 750ma setting, 10% drop in output current, v byp = 3.3v 220 350 mv 750ma setting, 1% drop in output current, v byp = 3.3v 220 turn-off time from flashen falling edge or torchen falling edge or timer expire until ramping of current on fled1/fled2 1.5 s fled1/fled2 current ramping down time taken for ramping current from 750ma setting to off setting 2 s fled1/fled2 leakage in shutdown v in_fled = 5.5v, v fled_ = 0v t a = +25c 0.01 5 a t a = +85c 0.1 a protection circuits flash duration timer in 62.5ms steps 62.5 1000 ms flash duration timer accuracy -10 +10 % flash safety timer reset inhibit period from falling edge of flashen or torchen or register bits until lash safety timer is reset 450 700 s torch timer range (can be disabled via i 2 c programming) in 0.262s steps 0.262 1.049 s in 0.524s steps 1.048 3.146 in 1.049s steps 3.145 7.340 in 2.097s steps 7.340 15.729 torch timer accuracy -10 +10 % open led protection threshold fled1 enabled v in_fled C 30mv mv shorted led protection threshold fled 1.0 v fled_ short debounce timer from fled_ short detected until fled_ current regulator is disabled C fled_ source is disabled after this timer to prevent excessive battery current 1 ms fled_ open debounce timer from fled_ open detected until fled_ current regulator is disabled C in_fled voltage is limited to 5.8v max C fled_ current source is disabled after this timer 8 ms led flash driver ec characteristics (continued) downloaded from: http:///
(v dc = 5v, v batt = 3.8v, t a = -40c to +85c, unless otherwise noted. typical values are at t a = +25c.) (note 2) (v sys = 3.7v, t a = -40c to +85c, unless otherwise noted. typical values are at t a = +25c.) (note 2) MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 10 safeout ldo parameter symbol conditions min typ max units safeout output voltage (default on) 5.0v < v dc < 5.5v, i safeout = 10ma, safeout[1:0] = 01b (default) 4.65 4.9 5.15 v safeout[1:0] = 00b 4.85 v safeout[1:0] = 10b 4.95 v safeout[1:0] = 11b 3.3 v maximum output current 60 ma output current limit 150 ma dropout voltage v chgin = 5v, i out = 60ma 120 mv load regulation v chgin = 5.5v, 30a < i out < 30ma 50 mv quiescent supply current not production tested 72 a output capacitor for stable operation (note 3) 0a < i safeout < 30ma, maximum esr = 50m? 0.7 1 f internal off-discharge resistance 1200 parameter symbol conditions min typ max units maxflashlow sys detect threshold range in 33mv steps 2.400 3.433 v low sys voltage threshold accuracy 2.5 % low sys voltage hysteresis programmable range in 100mv steps 100 300 mv low sys inhibit timer 256 2048 ms rising in 256s steps 256 2048 low sys inhibit time accuracy -10 +10 % flashen, torchen inputs pulldown resistor 400 800 1600 k input capacitance (note 3) 10 pf input low voltage v il 0.54 v input high voltage v ih 1.26 v led flash driver ec characteristics (continued) downloaded from: http:///
(v sys = 3.7v, t a = -40c to +85c, unless otherwise noted. typical values are at t a = +25c.) (note 2) MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 11 white led backlight driver parameter symbol conditions min typ max units step-up wled driver input voltage range 2.5 v ovlo v step-up converter quiescent current no switching, includes 20a for each current source 200 a step-up converter shutdown current v sys = 5.2v, all current sources disabled 1 a current source quiescent current v wledout = 20v, change in quiescent current when 1 current source is enabled or disabled 20 a step-up converter switching frequency bsten = 1, ledpwm duty cycle > 0 wledfosc = 00 0.667 mhz wledfosc = 11 1 maximum duty cycle wledfosc[1:0] =11 93 % soft-start duration 10 v/ms output voltage range v bat 35 v overvoltage protection threshold wledovp = 1 34.1 wledout leakage current v wledout = 5.5v, v sys = 5.2v, boost in shutdown (note 3) t a = +25c 0.12 a t a = +25c 2 a v wledout = 35v, v wledlx = 35v, boost in shutdown 25 a current source linear output range 8-bit linear dimming range (97.656a/lsb) 0 25 ma current source dropout voltage i wled_ = 25ma (programmed), (v wled_ - v wledgnd ) measured when i led_ has dropped to 90% of full-scale programmed level, v wledoout = 20v, t a = +25c 100 180 mv wled current accuracy i wled_ = 25ma, v wled_ = 0.5v above v wledgnd , v wledout = 20v, t a = +25c -1 +1 % wled current matching mismatch between w led1 and w led2 , i wled_ = 25ma, (v wled - v wledgnd ) = 0.5v, v wledout = 20v, t a = +25c -1 +1 % wled leakage current in shutdown v wledout = 35v, v wled_ = 35v t a = +25c 0.1 1 a t a = +85c 1 a wledlx leakage current v wledlx = 35v, v wledout = 35v t a = +25c -5 +0.1 +5 a t a = +85c 1 a n-channel on-resistance i wledlx = 175ma 400 m downloaded from: http:///
(v sys = 3.7v, t a = -40c to +85c, unless otherwise noted. typical values are at t a = +25c.) (note 2) (v sys = 3.7v, v io = 1.8v, t a = -40c to +85c, unless otherwise noted. typical values are at t a = +25c.) (note 2) MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 12 white led backlight driver (continued) parameter symbol conditions min typ max units n-channel current limit current regulation mode 935 1100 1265 ma wled_ voltage regulation maximum (v wled_ - v wledgnd ) below dropout voltage level of highest string 50 mv wled_ voltage regulation window nonskip mode 125 mv skip mode 487.5 mv wledpwm input frequency range external pwm input 5 60 khz wledpwm input duty cycle range 0 100 % wledpwm input current dimming range pwm duty = 0% to 100% 0 25 ma wledpwm input current v sys = 2.5v to 5.2v, v wledpwm = 0v and 5.2v -1 +1 a wledpwm input logic high v sys = 2.5v and 5.2v 1.2 v wledpwm input logic low v sys = 2.5v and 5.2v 0.4 v general, i2c, logic, and thermal parameter symbol conditions min typ max units shutdown supply current i sys all circuits off 15 30 a sys input range sys operating voltage guaranteed by v sysuvlo and v sysovlo 2.8 5 v sys undervoltage lockout threshold (sys uvlo) v sys falling, 200mv hysteresis 2.45 2.5 2.55 v sys overvoltage lockout threshold (sys ovlo) v sys rising, 200mv hysteresis 5.2 5.36 5.52 v low sys thresholds range programmable via lsdac register, v sys falling 2.60 3.35 v low sys hysteresis range programmable via lshyst register 100 400 mv thermal shutdown thermal shutdown threshold t j rising 165 c thermal shutdown hysteresis 15 c thermal interrupt 1 120 c thermal interrupt 2 140 c downloaded from: http:///
(v sys = 3.7v, v io = 1.8v, t a = -40c to +85c, unless otherwise noted. typical values are at t a = +25c.) (note 2) MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 13 general, i2c, logic, and thermal (continued) parameter symbol conditions min typ max units logic and control inputs scl, sda input low level t a = +25c 0.3 x v io v scl, sda input high level t a = +25c 0.7 x v io v scl, sda input hysteresis t a = +25c 0.05 x v io v scl, sda logic input current v io = 3.6v -10 +10 a scl, sda input capacitance 10 pf sda output low voltage sinking 20ma 0.4 v output low voltage reset , int i sink = 1ma 0.4 v mrst input low level t a = +25c 0.4 v mrst input high level t a = +25c 1.4 v mrst input hysteresis t a = +25c 0.1 v mrst input current v sys = 5.5v t a = +25c -2 0 +2 a t a = +85c 0.1 output high leakage reset , int v sys = 5.5v t a = +25c -1 0 +1 a t a = +85c 0.1 interrupt debounce filter timer lowsys 16 ms reset deassert delay 60 ms manual reset debounce timer the period between ( mrst = low) and automatic reboot start 3 s 45 6 7 (default) 89 10 downloaded from: http:///
(v sys = 3.7v, v io = 1.8v, t a = -40c to +85c, unless otherwise noted. typical values are at t a = +25c.) (note 2) MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 14 general, i2c, logic, and thermal (continued) parameter symbol conditions min typ max units i 2 c interface (note 3) clock frequency 100 400 khz bus-free time between start and stop 1.3 s hold time repeated start condition 0.6 s scl low period 1.3 s scl high period 0.6 s setup time repeated start condition 0.6 s sda hold time 0 s sda setup time 100 ns maximum pulse width of spikes that must be suppressed by the input filter of both sda and scl signals 50 ns setup time for stop condition 0.26 s note 2: limits are 100% tested at t a = +25 c. limits over the operating temperature range and relevant supply voltage range are guaranteed by design and characterization. note 3: note production tested. guaranteed by design. downloaded from: http:///
MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 15 bump coniguration 1 2 3 4 5 6 7 8 a + top view (bump side down) gnd_a in_fled dc byp lx pgchg pgchg mbattdet b fled2 torchen dc bst lx cschg fet_drv vchg c fled1 flashen1 inok avl pvl cs syss sys d safeout int chggnd mbatrsnsn mbatrsnsp agnd_chg thm mbatt e gnd_a vcctest test2 gnd_a mrst test4 sys_a sys_a f vio sda scl gnd_d test3 wledgnd reset wledpgnd g vio test1 wled1 wled2 wledpwm wledout wledlx wledlx MAX77829 wlp ( 0 . 4mm pitch ) n. c . pins are floating and can be connected at board-level if needed . ground all test pins ( test_ and vcctest ). downloaded from: http:///
MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 16 bump description bump name function a3, b3 dc high-current charger input. bypass to pgndc with a 1f/25v ceramic capacitor. reverse boost output. a4 byp connection point between reverse blocking mosfet and high-side switching mosfet. bypass to pgnd with a 4.7f/25v ceramic capacitor. reverse boost regulation node. a5, b5 lx buck/boost inductor connection. connect the inductor between lxchg and cs. a6, a7 pgchg power ground for charger step-down low-side fet. a8 mbatdet battery detection active-low input. connect mbatdet to the id pin on the battery pack. if mbatdet is pulled to ground, this indicates that the battery is present and the charger starts when valid dc power is present. mbatdet driven high or left unconnected indicates that the battery is not present and the charger will not start. mbatdet is pulled high to avl through an internal 470k resistor. b4 bst high-side fet driver supply. bypass bst to lxc with a 0.1f ceramic capacitor. b6 gschg ic substrate ground b7 fet_drv battery fet gate driver b8 vichg charging current monitor c3 inok charger input valid logic output flag. open-drain, active-low output that indicates when valid voltage is present at both chgin and sys. this signal is often needed by the main pmic or the applications processor. c4 avl internal bias regulator quiet analog bypass pin. internal 10 connection between pvl and avl forms lp ilter with a 4.7f external bypass capacitor to gndchg. c5 pvl internal bias regulator high-current output bypass pin. supports internal noisy and high-current gate drive loads. bypass to pgndchg with a minimum 4.7f ceramic capacitor. c6 cs charger current sense positive terminal c7 syss charger current sense negative terminal and system voltage sense terminal c8 sys system power for linear charger. boost supply during startup. d3 chgind charging status indication. open-drain, active-low output that indicates when the charging is active. d4 mbatrsnsn battery current sense negative terminal d5 mbatrsnsp battery current sense positive terminal d6 agnd_chg charger analog ground d7 thm battery thermistor terminal/battery detection d8 mbatt battery positive terminal. bypass to agnd with a 4.7f ceramic capacitor. c1 fled1 flash led current source output 1. connect fled1 to the anode of a high-brightness led and cathode tied to the ground plane. fled1 has an internal tbdk resistor to gnd. b1 fled2 flash led current source output 2. connect fled2 to the anode of a high-brightness led and cathode tied to the ground plane. fled2 has an internal tbdk resistor to gnd. downloaded from: http:///
MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 17 bump description (continued) bump name function a2 in_fled flash led driver input. bypass to gnd with 4.7f ceramic capacitor. b2 torchen torch mode enable active-high logic input. torchen has on-chip 800kohm pull-down resistor. c2 flashen1 flash strobe #1 enable active-high logic input. flashen1 has an internal 800k pull-down resistor. d1 safeout safeout ldo output. default 4.9v and on when chgin power is valid. bypass with a 1f ceramic capacitor to gnd. f6 wledgnd ground for wled current drivers f8 wledpgnd power ground for wled boost converter g3 wled1 current source output for wled1 boost converter string. when powering series leds, the anode of the led string should connect to led. g4 wled2 current source output for wled2 boost converter string. when powering series leds, the anode of the led string should connect to led. g5 wledpwm content-based adaptive brightness control input for led boost converter. wledpwm accepts a logic-level pwm signal with a frequency range of 5khz to 60khz. g6 wledout boost converter overvoltage sense input. bypass wledout to wledpgnd with a 1f ceramic capacitor. g7, g8 wledlx wled switching node d2 int interrupt output. active-low open-drain output. e5 mrst manual reset input for hardware reset with internal timer f1,g1 vio digital i/o supply input for i 2 c interface f2 sda i 2 c serial data for MAX77829, except the fuel gauge f3 scl i 2 c serial clock for MAX77829, except the fuel gauge f7 reset reset output. active-low open-drain output with timer. provides manual reset capability to applications processors when the main pmic is not already providing this function. a1,e1 e4 gnd_a analog ground e7, e8 sys_a analog sys input. share with sys_q f4 gnd_d digital ground e2 vcctest test pin. connect to ground. e3 test2 test pin. connect to ground. e6 test4 test pin. connect to ground. f5 test3 test pin. connect to ground. g2 test1 test pin. connect to ground. downloaded from: http:///
MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 18 functional diagram 1.5a camera led flash driver (750ma/ch) boost wled backlight driver ovp isense and otg switch ref and bias safeout ldo 2.0a switching charger w/ external power path and reverse boost for otg and flash i 2 c serial bus and register vbus+5vdc safeout v sys vio scl sda intb mrstb reset inokb flashen torchen li-ion battery vsys vbyp flash wled MAX77829 flash wled downloaded from: http:///
detailed description main-battery charger the MAX77829 charger is a compact, high-frequency, high-efficiency switch-mode charger for a one-cell lithium ion (li+) battery with otg capability and support to drive external p-channel mosfet power-path. it delivers up to 2.0a of current to the battery from inputs up to 9.4v for dc and withstands transient inputs up to 22v. the typi - cal 4mhz switch-mode charger is ideally suited for small portable devices such as headsets and ultra-portable media players because it minimizes component size and heat. the MAX77829 has programmable automatic input current limiting to protect upstream charging sources from collapsing. upon request from the host processor, the MAX77829 can run its switching regulator in reverse to support usb on the go power, +5v at 500ma (default, up to 900ma with different factory setting). the MAX77829 can manage two outputs independently, battery charging and system power. this allows immedi - ate system operation under missing/deeply discharged battery conditions. battery protection features include low voltage prequali - fication, charge fault timer, die temperature monitoring, battery temperature monitoring and watchdog timer. the battery temperature monitoring adjusts the charge current and termination voltage for safe use of secondary lithium- ion batteries. features eficient 4mhz (typ) switch mode charger support - ing 2.0a charging current capability usb otg supports 500ma at +5v dc (default set- ting, up to 900ma with different factory setting) external power-path p-mosfet driver for no/dead battery support digital programming via i 2 c interface: ? input current limit (up to 2.0a) ? fast charge current (up to 2.0a) ? termination current ? restart voltage ? safety timer/watchdog timer high-accuracy voltage and current regulation input current regulation: 5%(100ma, 500ma), 10%( 1a), default 500ma charger voltage regulation: 0.5% 250c, adjustable from 3.55v to 4.4v fast charge current regulation: 0.25a to 2.0a 5%, default 500ma 22v absolute maximum input voltage rating up to +9.4v maximum operating input voltage input voltage based automatic input current limit (aicl) battery/system load current sensing and limiting jeita compliance thermistor monitoring of bat- tery temperature and adjust charging current and voltage battery protection: ? reverse leakage protection prevents battery drainage ? input/output overvoltage protection ? battery over temperature protection ? thermal regulation and shutdown ? battery overcurrent alarm system voltage regulator/battery charger with power-path: ? external p-mosfet driver for power-path and battery charging ? supplement mode to delivery current from bat- tery during power -path operation battery presence detection interrupt status output input/output overvoltage protection thermal regulation protection charging status indicator MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 19 downloaded from: http:///
figure 1. main-battery charger typical application circuit MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 20 buck/ reverse boost control mbatt lxchg pgchg bat+ l chg , 1h c bst 0.1f c mbatt 2.2f system load r cs 47m , 1/4w cs fet_drv mbatrsnsp bat- q4 q5 q6 battery pack mbatrsnsn gmi syss c sys 10f sys sys powers internal circuits bst 100k fet driver bat2sys oc thm ntc r batoc 5m vio c dc 2.2f gmv gmv boost vfb = byp vreg = minsys or mbatreg fc_i ( dcilim, aicl, temp) avl agnd_chg pvl 10 c pvl 10f c avl 10f avl powers internal circuits input current limit, aicl, otgilim dc supports usb otg, 5v/500ma c dc 2.2f max +9.4v operation vpquth syss mbatt linear: byp2sys byp2bat sys2bat byp sys thermistor hot warm cool cold battery detection control logic vsys vsys 100 k? chgindinokb sup MAX77829 q2 vfb = syss or mbatt 5v 100ma ldo bypass switch byp downloaded from: http:///
inductor selection the charger operates with a switching frequency of 4mhz and uses a 1h or 2.2h inductor. this operating frequency allows the use of physically small inductors while maintaining high efficiency. the inductors dc cur - rent rating only needs to match the maximum load of the application because the MAX77829 features zero current overshoot during startup and load transients. for opti - mum transient response and high efficiency, choose an inductor with dc series resistance in the 40m to 120m range. see table 1 below for suggested inductors and manufacturers. mbat capacitor selection (c mbatt ) choose the nominal mbat capacitance (c mbatt ) to be 2.2f. the mbat capacitor is required to keep the mbat voltage ripple small and to ensure regulation loop stability. the mbat capacitor must have low impedance at the switching frequency. ceramic capacitors with x5r or x7r dielectric are highly recommended due to their small size, low esr, and small temperature coefficients. for optimum load-transient performance and very low output voltage ripple, the mbat capacitor value can be increased above 2.2f. as the case sizes of ceramic surface-mount capaci - tors decreases, their capacitance vs. dc bias voltage characteristic becomes poor. due to this characteristic, it is possible for 0603 capacitors to perform well while 0402 capacitors of the same value perform poorly. the recommended nominal mbat capacitance is 2.2f, however, after initial tolerance, bias voltage, aging, and temperature derating, the capacitance must be greater than 1.5f. with the capacitor technology that is available at the time the MAX77829 was released to production, the mbat capacitance is best achieved with a single ceramic capacitor (x5r or x7r) in a 0402 case size. the capacitor voltage ratings should be 6.3v or greater. sys capacitor selection (c sys ) choose the nominal sys capacitance (c sys ) to be 10f. c sys is the output capacitor for the step-down converter when charging. alternatively, c sys is the input capaci - tor for the stepup converter when it is operating in otg mode. c sys is required to keep the sys voltage ripple small and to ensure regulation loop stability. in a typical application, sys also powers many other elements the MAX77829 power-soc as well as system elements. although the sum total of capacitance on sys may be ~50f it is critical that a local c sys is provided to reduce the current loops created by the dc-dc. c sys must have low impedance at the switching fre - quency. ceramic capacitors with x5r or x7r dielectric are highly recommended due to their small size, low esr, and small temperature coefficients. for optimum load- transient performance and very low output voltage ripple, the mbat capacitor value can be increased above10f. as the case sizes of ceramic surface-mount capacitors decreases, their capacitance vs. dc bias voltage char - acteristic becomes poor. due to this characteristic, it is possible for 0603 capacitors to perform well while 0402 capacitors of the same value perform poorly. the recom - mended nominal c sys is 10f, however, after initial toler - ance, bias voltage, aging, and temperature derating, the capacitance must be greater than 6f. with the capacitor technology that is available at the time the MAX77829 was released to production, the sys capacitance is best achieved with a single ceramic capacitor (x5r or x7r) in an 0603 case size. the capacitor voltage ratings should be 6.3v or greater. table 1. suggested inductors MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 21 manufacturer series inductance (h) esr () current rating (ma) dimensions (mm) taiyo yuden makk2016 1 0.1 2500 2.0 x 1.6 x 1.0 tdk tfa2016g 1 0.13 2500 2.0 x 1.6 x 1.0 tdk mlp2520s 1.0 0.06 1500 2.0 x 2.5 x 1.0 tdk vls252012 1 0.105 2700 2.5 x 2.0 x 1.2 toko mipf2520 2.2 0.05 1500 2.5 x 2.0 x 1.0 toko dfe252012c 1 0.06 2500 2.5 x 2.0 x 1.2 fdk mipsa2520d1r0 1.0 0.08 1500 2.5 x 2.0 x 1.2 murata lqm2hpn_g0 1.0 0.05 1600 2.5 x 2.0 x 0.6 murata lqm32pn1r0mg0 1 0.06 1800 3.2 x 2.5 x 0.9 coilcraft epl2014 1.0 0.059 1600 2.0 x 2.0 x 1.4 downloaded from: http:///
byp capacitor selection (c byp ) choose the nominal byp capacitance (c byp ) to be 2.2f. c byp is the input capacitor for the step-down con - verter when charging. alternatively, c byp is the output capacitor for the reverse boost converter. larger value of c byp improves the decoupling for the dc-dc converter, but may cause high dc to byp inrush currents when an input adapter is connected. to limit the inrush current, c byp must be no larger than 4.7f. c byp reduces the current peaks drawn from the input power source when charging. similarly, c byp reduces the output voltage ripple of the stepup converter when it is operating in otg mode. the impedance of the input capacitor at the switching frequency should be very low. ceramic capacitors with x5r or x7r dielectric are highly recommended due to their small size, low esr, and small temperature coefficients. to fully utilize the +22v input capability of the MAX77829, choose c byp to have a 25v or greater rating; many applications do not need to utilize the full input capability of the device and find that a 16v rating input capacitor is sufficient. c byp is a critical discontinuous current path that requires careful bypassing. in the pcb layout, place c byp as close as possible to the power pins (byp and pgchg) to minimize parasitic inductance. if making connections to c byp through vias, ensure that the vias are rated for the expected input current so they do not contribute excess inductance and resistance between the bypass capacitor and the power pins. the expected c byp current is the same as the isat (see the inductor selection section). c byp must meet the input ripple current requirement imposed by dc-dc converter. ceramic capacitors are preferred due to their low esr and resilience to surge cur - rents. choose the c byp capacitor so that its temperature rise due to ripple-current does not exceed approximately +10c. for a step-down regulator, the maximum input ripple current is half of the output current. this maximum input ripple current occurs when the step-down converter operates as 50% duty cycle (v in = 2 x v bat ). bst capacitor selection (c bst ) choose the nominal bst capacitance (c bst ) to be 0.1f. c bst is part of a charge pump that creates the high-side gate drive for the dc-dc. if larger values of larger values of c bst are used, ensure that cpvl is always 10 times larger than c bst . the maximum expected working volt - age of c bst is the same as the pvl regulation voltage (~5v). however, it is recommended that the c bst has at least 10v rating. with the capacitor technology that is available at the time the MAX77829 was released to pro - duction, it is possible to find a 10v ceramic 0.1f 0201 capacitor however these devices are pushing the limits, and a 10v ceramic 0.1f 0402 may be more cost effec - tive and readily available. dc input capacitor selection (c dc ) choose the nominal dc capacitance (c dc ) to be 2.2f. c dc is intended to decouple a charge source and its par - asitic impedance. typically, the charger source at dc is a usb connectors v bus . larger values of c dc improve the decoupling of the charger source impedance; how - ever, take care not to exceed the maximum capacitance allowed by the usb specification (i.e. 10f and 50c). note that for the usb input capacitance specification, c dc is effectively in parallel with c byp and therefore the sum of these two capacitances should be less than 10f. the impedance of the cdc at the dc-dc switching fre - quency should be very low. ceramic capacitors with x5r or x7r dielectric are highly recommended due to their small size, low esr, and small temperature coefficients. to fully utilize the +22v input capability of the MAX77829, choose cdc to have a 25v or greater rating; many appli - cations dont need to utilize the full input capability of the device and find that a 16v or 10v rated input capacitor is sufficient. charge current resistor selection both the top-off current range and fast charge current range depends on the sensing resistor (r sns ). the rec - ommended resistor value is 47m? 0.125w 2%. 2 rsns charge sns 2 rsns pi r p (2.0a) 0.047 0.188w = = ?= calculate the cc mode charge current step from the chgcc voltage setting and sense resistor as follows: charge_current_step sns v(chgcc) i r = table 2 below shows the charge current settings for two sensing resistors. table 2.charge current settings for 47m? sense resistor MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 22 bit v i(reg) (mv) i charge (ma) r sns = 47m? v (chgcc<11110>) 70.5 1500 v (chgcc<10100>) 47 1000 v (chgcc<01010>) 23.5 500 downloaded from: http:///
calculate the top-off charge current step as follows: charge_current_step sns v(top_off) i r = table 3 shows the top-off current settings for two sensing resistors.dc input C fast hysteretic step-down regulator when a valid dc input is present, battery charging is sup - plied by the high-frequency step-down regulator from dc. the step-down regulation point is then controlled by three feedback signals: maximum step-down output current programmed by the input current limit, maximum charger current programmed for the fast charge current and maxi - mum die temperature. the feedback signal requiring the smallest current controls the average output current in the inductor. this scheme minimizes total power dissipation for battery charging and allows the battery to absorb any load transients with minimum voltage disturbance. a proprietary hysteretic current pwm control scheme ensures fast switching and physically tiny external com - ponents. the feedback control signal that requires the smallest input current controls the center of the peak and valley currents in the inductor. the ripple current is internally set to provide 4mhz operation. when the input voltage decreases near the output voltage, very high duty cycle occurs and, due to minimum off-time, 4mhz operation is not achievable. the controller then provides minimum off-time, peak current regulation. similarly, when the input voltage is too high to allow 4mhz operation due to the minimum off-time, the controller becomes a mini - mum on-time, valley current regulator. in this way, ripple current in the inductor is always as small as possible to reduce ripple voltage on battery for a given capacitance. the ripple current is made to vary with input voltage and output voltage in a way that reduces frequency variation. however, the frequency still varies somewhat with operat - ing conditions.soft-start to prevent input current transients, the rate of change of the input current (di/dt) and charge current is lim - ited. when the input is valid, the charge current ramps from 0ma to the fast-charge current value in 1.5ms. charge current also soft-starts when transitioning from the prequalification state to the fast-charge state. there is no di/dt limiting when transitioning from the done state to the fast-charge state. pvl and avl as shown in figure 1 , avl is the output of a 5v/100ma linear regulator when power from byp is available. if only power from sys is available, then pvl is connected to sys with a bypass switch. when avl is greater than 2.7v the internal control circuits for the charger are enabled. connect a 10f ceramic capacitor from avl to agnd (cavl). powering external loads from avl is acceptable, provided that they do not consume more than 100ma. pvl powers the gate drivers and bst for the main-battery chargers step-down regulator, it also charges the bst capacitor. pvl is the filtered version of avl. the filter consists of an internal 10? resistor and the pvl external bypass capacitor (10f). this filter creates a 100khz lowpass filter that cleans the 4mhz switching noise from the analog portion of the MAX77829. connect a 10f ceramic capacitor from pvl to pgchg (cpvl). powering external loads from pvl is not recommended. thermistor input (thm) the thm input connects to an external negative tem - perature coefficient (ntc) thermistor to monitor battery or system temperature. charging is suspended when the thermistor temperature is out of range. the charge timers are suspended and hold their state but no fault is indicated. when the thermistor comes back into range, charging resumes and the charge timer continues from where it left. connecting thm to gnd disables the therm - istor monitoring function. table 3. top-off current settings for 47m? sense resistor table 4. suggested p-channel mosfet MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 23 bit v (top-off) i (top-off) (ma) r sns = 47m? v (top-off<>) 9.4 200 v (top-off<>) 4.7 100 v (top-off<>) 2.35 50 manufacturer part number part description dimensions vishay sia443dj pfet, 20v, sc70 power pak 2.05mm x 2.05mm x 1.0mm = 4.2mm3 si4435ddy pfet, 30v, so-8 6.2mm x 5.0mm x 1.75mm fairchild fdma905p pfet, 20v, sc70 2mm x 2mm x 1mm = 4mm3 downloaded from: http:///
since the thermistor monitoring circuit employs an exter - nal bias resistor from thm to avl, the thermistor is not limited only to 10k (at 25oc). any resistance thermis - tor can be used as long as the value is equivalent to the thermistors +25c resistance. for example, with a 10k at rtb resistor, the charger enters a temperature suspend state when the thermistor resistance falls below 3.97k (too hot) or rises above 28.7k (too cold). this corresponds to 0c to +50c range when using a 10k ntc thermistor with a beta of 3500k. the general relation of thermistor resistance to temperature is defined by the following equation: 11 t 273 298 thrm 25 r re ?? ?? ? ?? ?? + ?? ?? = where:r thrm = resistance in of the thermistor at temperature t in c. r 25 = resistance in of the thermistor at +25oc. = material constant of the thermistor, which typically ranges from 3000k to 5000k. t = temperature of the thermistor in c. some designs might prefer other thermistor temperature limits. threshold adjustment can be accommodated by charging r tb , connecting a resistor in series and/or in parallel with the thermistor, or using a thermistor with different . for example, a +45oc hot threshold and 0c cold threshold can be realized by using a thermistor with a to 4250k and connecting 120k in parallel. since the thermistor resistance near 0c is much higher than it is near +50c, a large parallel resistance lowers the cold threshold, while only slightly lowering the hot threshold. conversely, a small series resistance raises the cold threshold, while only slightly raising the hot threshold. raising r tb , lowers both the hot and cold threshold, while lowering r tb raises both thresholds. note that since avl is active whenever valid input power is connected at dc, thermistor bias current flows at all times, even when charging is disabled. with a 10k thermistor and a 10k pullup to avl, this results in an additional 250a load. this load can be reduced to 25a by instead using a 100k thermistor and 100k pull-up resistor. thermal foldback thermal foldback maximizes the battery charge current while regulating the MAX77829 junction temperature. when the die temperature exceeds treg, a thermal limiting circuit reduces the battery charge-current target until the charge current reaches 25% of the fast-charge current setting. the charger maintains 25% of the fast- charge current until the die temperature reaches tshdn. please note that the MAX77829 is rated for a maximum ambient temperature of +85c. furthermore, although the maximum die temperature of the MAX77829 is +150c, it is common industry practice to design systems in such a way that the die temperature never exceeds +125c. limiting the maximum die temperature to +125c extends long-term reliability. boost mode when enabled as a boost converter, in the absence of a valid charger input, the dc-dc converter is allowed to operate as a boost converter. the boost output voltage is regulated to 5.1v. the boost switches at 4mhz and is capable of delivering up to 500ma. the processor must enabled otg mode by software via otgen bit. the reverse blocking switch allows the delivery of power to the charger input. table 5. calculated values for different thermistors MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 24 parameter value r thm at t a = +25c 10,000 10,000 10,000 47,000 47,000 100,000 100,000 thermistor beta (|) 3380 3940 3940 4050 4050 4250 4250 r tb() 10,000 10,000 10,000 47,000 47,000 100,000 100,000 r tp() open open 301,000 open 1,200,000 open 1,800,000 r ts() short short 499 short 2,400 short 6,800 resistance at t1_n15() 61,788 61,788 77,248 290,410 380,716 617,913 934,027 resistance at t1_0() 29,308 29,308 31,971 137,750 153,211 293,090 343,283 downloaded from: http:///
charger states the MAX77829 utilizes several charging states to safely and quickly charge batteries. figure 2 shows an exag - gerated view of a li+/li-poly battery progressing through the following charge states when the die and battery are close to room temperature: dead-battery ? precharge ? fast-charge ? top-off ? done. figure 2. li+/li-poly/lifepo4 charge profile MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 25 v pquth v mbatreg i chg i set i topoff low-batterypre-charge chg_dtls[3:0] = 0b0001 fast charge (cc) chg_dtls[3:0] = 0b0010 battery voltage battery charge current i prechg v pqlth timetime v mbat_ref restart fast charge (cv) chg_dtls[3:0] = 0b0011 0v fast charge (cv) chg_dtls[3:0] = 0b0011top-off chg_dtls[3:0] = 0b0100 done chg_dtls[3:0] = 0b0101 done chg_dtls[3:0] = 0b0101 states 0a i pqlth charger enabled dead-battery chg_dtls[3:0] = 0b0000 note1 note1: a typical li+/li-poly has an internal battery pack protection circuit that will open the battery connection when the batterys cell voltage is lower than a dead battery threshold (v pqlth.falling ~2.5v). to get the pack protection to close again, the cl12 charges the battery capacitor with i dbat until the voltage exceeds v pqlth . then the cl12 charges the battery capacitor with i prechg . when the battery capacitors voltage exceeds v pquth.rising , then the power-path fet closes which connects the cell to the cl12 charger. not to scale, v dc = 5.0v, i sys = 0a, t j = 25c top-off chg_dtls[3:0] = 0b0100 4.0v system voltage v mbatreg + (i*extmos) v pquth downloaded from: http:///
charger disabled state when dc is low or the input voltage is out of range, the MAX77829 disables the charger. to exit this state, the input voltage must be within its valid range. dead-battery state when a deeply discharged battery is inserted with a voltage of less than v pqlth , the MAX77829 disabled the switching charger and linearly charges with i pqlth . once v bat increases beyond v pqlth , the MAX77829 transitions to the precharge state. this state prevents the MAX77829 from dissipating excessive power in the event of a shorted battery. precharge state the precharge state occurs when the battery voltage is greater than v pqlth and less than v pquth . in this state, the dead-battery linear and system to bat - tery linear charger turns on to provide i prechg current to sys. if the MAX77829 remains in this state for longer than t prechg , then the MAX77829 transitions to the timer fault state. a normal battery typically stays in the prequalification state for several minutes or less and when the battery voltage rises above v pquth , the MAX77829 transitions to the fast-charge constant current state.fast charge constant current state the fast-charge constant current state occurs when the battery voltage is greater than v pquth and less than v batreg . in this state, the switching charger is on and delivering current to the battery. the total battery current is ifc. if the MAX77829 remains in this state and the fast- charge constant voltage state for longer than t fc , then the MAX77829 transitions to the timer fault state. when the battery voltage rises to v batreg , the MAX77829 transitions to the fast-charge constant voltage state. when jeita is enabled (jeita_en = 1), the fast-charge constant current is set to 50% of programmed value when -10c < thm <15c, and 100% of programmed value when 15c < thm < 60c. the MAX77829 dissipates the most power in the fast- charge constant current state. this power dissipation causes the internal die temperature to rise. if the die tem - perature exceeds t reg , i fc is reduced. if there is low input voltage headroom (v dc C v mbat ), then i fchg decreases due to the impedance from in to b at. fast charge constant voltage state the fast-charge constant voltage state occurs when the battery voltage is at the vmbatreg[3:0] and the charge current is greater than i done . in this state, the switching charge is on and delivering current to the battery. the MAX77829 maintains v batreg and monitors the charge current to detect when the battery consumes less than the done current. when the charge current decreases below the i done threshold, the MAX77829 transitions to the top-off state. if the MAX77829 remains in the fast-charge constant current state for longer than t fchg , then the MAX77829 transitions to the timer fault state. top-off state the top-off state occurs when the battery voltage is at v batreg and the battery current decreases below i done current. in this state, the switching charger is on and delivers current to the battery. the MAX77829 maintains v batreg for a specified time. when this time expires, the MAX77829 transitions to the done state. if the charging current increases to i done + 200ma before this time expires, then the charge reenters the fast-charge constant voltage state. done state the MAX77829 enters its done state after the charge has been in the top-off state for topoff. in this state, the switching charger is off and no current is delivered to the battery. if the system load presented to the battery is low << 10a, then a typical system can remain in the done state for many days. if left in the done state long enough, the battery voltage decays below the restart threshold (v mbat_ref ) and the MAX77829 transitions back into the fast-charge state. there is no soft-start (di/dt limiting) during the done-to-fast-charge state transition. timer fault state the timer fault state occurs when either the prequalifica - tion or fast-charge timers expire. in this state, the charger is off. the charger can exit this timer fault state by cycling input power. MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 26 downloaded from: http:///
figure 3. charging state diagram MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 27 no pwr charger disabled chg_dtls = 0b1000 chg_ok = 1 ibat = 0 chg timer = 0 wd timer = 0 dc is valid and enabled(buck_en = 1), charger programmed enabled (cen = 1) chg timer resumes wd timer resumes pre-charge chg_dtls = 0b0001 ibat = i prechg fet_drv = off vsys = v sysreg[2:0] any state except thermal shutdown dc is invalid or disabled (buck_en = 0) deadbat chg_dtls = 0b000 ibat = i pqlth fet_drv = off vsys = v sysreg[2:0] fast chg chg_dtls = 0b0010 ibat = i fchg fet_drv = on v sys = v mbatreg[7:3] vbat > v pqlth vbat > v prequth vbat < v prequth timer fault irqb = low ibat = 0 timer > t prechg constant voltage chg_dtls = 0b0011 fet_drv = on v sys = v mbatreg[7:3] done irqb = low chg_dtls = 0b0101 fet_drv = off v sys = v mbatreg[7:3] ibat = 0 v mbat < v mbat_ref set t fchg = 0 vin too high irqb = low ibat = 0 any charging state dead bat, prequal, fast charge or top-off battery cold irqb = low, ibat = 0, if vbat > v pqlth battery hot irqb = low, ibat = 0, if vbat > v pqlth vdc > vovlo timer = suspend vdc < vovlo timer = resume thermistor > t1 timer = resume thermistor < t1 timer = suspend thermistor > t4 timer = suspend thermistor < t4 timer = resume timer >t topoff thermal shutdown chg_dtls = 0b1010 ibat = 0 t j < t shdn (chg timer = suspend wd timer = suspend) t j >t shdn (chg timer = 0 wd timer = 0) timer > t fchg timer > t prechg vbat < v pqlth topoff chg_dtls = 0b0100 irqb = low fet_drv = on v sys = v mbatreg[7:3] i mbat > i done + 200ma set t fchg = 0 i mbat < i done v mbat < v mattreg[7:4] v mbat > = v mattreg[7:4] downloaded from: http:///
input current limitthe default settings of the i dc_ilim control bits are such that when a charge source is applied to dc, the MAX77829 will turn on its dc-dc converter in buck mode, limit v sys to v sysmin , and limit the charge source current to 500ma. all control bits are reset on global shutdown. automatic input current limit (aicl) the MAX77829 includes the automatic input current limit (aicl) feature for the dc input. the amplifiers required for sensing the currents and associated logic circuitry for making decisions and changing the battery- charger current are fully integrated in the ics. this not only helps in reducing cost but also improves the speed of system response. the MAX77829 aicl works by monitoring the current being drawn from dc and comparing it to the pro - grammed current limit. the current limit is set based on the current-handling capability of the usb. generally, this limit is chosen to optimally fulfill the system power requirements while achieving a satisfactory charging time for the batteries. if the ac-adapter current exceeds the set threshold, the charger responds by cutting back on the charger current, thereby keeping the current drawn from the ac adapter within the set limit. this aicl fea - ture allows for reducing the ac adapter size and cost. the input current limit has two control inputs, one based on voltage and one based on current. the voltage input monitors the input voltage, and when it drops below the desired input (vdc_aicl), it generates a flag (aicl) to decrement the fast-charge current. when the voltage comparator initially trips at vdc_aicl, fast-charge current decrements at a slow rate, allow - ing the charger output to settle until the voltage on dc returns above this voltage threshold. once the dc voltage resolves itself, the current delivery of the adapter is maxi - mized. in the event of a limited input current source, an example being a 500ma adaptor plugged into a 1a input current limit setting, a second voltage comparator set at vdc_aicl - 100mv triggers and throttles the fast-charge current to a minimum of 75ma. once the dc voltage cor - rects itself to above vdc_aicl, the fast-charge level is checked every 16ms to allow the system to recover if the available input power increases. the current-limit input monitors the current through the input fet and generates a flag (dc_i) to decre- ment the fast-charge current when the input limit is exceeded. the fast-charge current is slowly decre- mented until the input-limit condition is cleared. at this point, the fast-charge current is maintained for 16ms and is then sampled again. battery detection the MAX77829 charger detects insertion and removal of battery packs under various conditions. when a valid power source is detected on dc pin, the battery detection state machine is enabled. the first task is to determine the type of detection method used for predicting battery present condition. the voltage level on the mbatdet pin is used to determine the presence of either a low-cost battery or a smart battery. jeita description the MAX77829 safely charges a single li+ cell in accor - dance with jeita specifications. the MAX77829 monitors the battery temperature while charging and automatically adjusts the fast-charge current and/or charge termination voltage as the battery temperature varies. in safety region 1, the MAX77829 automatically reduces the fast-charging current for t mbatt < +10c and reduc - es the charge termination voltage from 4.200v (25mv) to 4.075v (25mv) for t mbatt > +45c. the fast-charge current is reduced to 50% of the nominal fast-charge cur - rent. when battery charge current is reduced by 50%, the timer is doubled. in safety region 2, the ic automatically reduces the charge termination voltage from 4.200v (25mv) to 4.075v (25mv) for t mbatt < +10c and for t mbatt > +45c. the fast-charge current is not changed in safety region 2. the customer can disable t2 and t3 temperature scaling for voltage and current by programming jeita_en bit to disable (jeita_en=0). in this case, only t1 and t4 tem - perature region will be enabled. MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 28 downloaded from: http:///
figure 4. automatic input current limit diagram MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 29 is the increment 1lsb of chgcc during increasing? 4.5v 16ms 16ms vdc beyond 4.53v aicl start working is the decrement 1lsb of chgcc during decreasing? variable ichg 4.4v 4.5v 16ms 16ms vdc beyond 4.5v aicl start working voltage has to rise above 4.53v before counting up starts again, each step is ~150s after that. ichg 4.4v is the decrement 1lsb of chgcc? ichg = 75ma no detection time for the 4.5v comparator is approx. 2secs 2) second comparator triggered (4.4v) 1) 4.5v comparator tripped decrements at 1/14 th of chgcc set value voltage needs to go above 4.53v before 16ms starts downloaded from: http:///
led flash driverdescription the flash driver integrates an adaptive pwm step-up dc-dc converter (shared with switch-mode charger mod - ule) and two high-side current regulators cable of deliver - ing up to 750ma/ch for flash applications and 187.5ma/ ch for torch mode. a serial interface controls the step-up output voltage setting, the torch/flash current, and the torch/flash timers. when valid v dc is present, flash led driver operates only when v dc < v dc_v . features step-up dc-dc converter ? adaptive regulation for driving the led directly ? see the charger section for feature list flash current regulator ? 2x high-side current regulators simpliies pcb heat sinking ? low dropout speciication 160mv (typ) at 750ma ? i 2 c programmable flash output current (11.72ma to 750ma in 64 steps) per channel ? i 2 c programmable torch output current (11.72ma to 187.5ma in 16 steps) per channel programmable flash safety timer (62.5ms to 1000ms in 16 steps) C this timer cannot be disabled programmable torch timer (262ms to 15.728s in 16 steps) C or continuous torch current (disable option on the torch timer) maxflash system lock-up protection open/short led protection dedicated flashen and torchen inputs figure 5. jeita safety region MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 30 10c 0 0 c/ -10c 25c 45c 60c 85c 4.0v 4.1v 4.2v t1 t3 25mv +/-25mv 4.075v temperature charge termination voltage safety region 1 safety region 2 10c 0c/-10c 25c 45c 60c 85c 0.5c temperature fast charge current c t1 t2 t4 t3 t2 t4 downloaded from: http:///
boost converterthe MAX77829 flash driver integrates an adaptive pwm step-up dc-dc converter (shared with switched mode charger module) and two high-side current regulators capable of delivering up to 750ma each, for flash applica - tions. the serial interface controls individual output on/off, the step-up output voltage setting, the torch/flash current, and the torch/flash timer duration settings. current source (fled1 and fled2) the MAX77829 provides two high-side, low-dropout, linear current regulators. the led current regulators can operate in either torch or flash mode. each current source is programmable and regulated up to 375ma in torch mode and up to 750ma in flash mode. fled cur - rent is programmable with 23.436ma/lsb resolution in torch and flash modes. torch mode can be enabled either using the serial inter - face or by logic control using the torchen or flashen inputs. see the description of the flash_en register for more information about programming the fled enable behavior. torch mode provides continuous lighting when enabled. the time duration is controlled through the torch timer, enabling the user to limit the duration of torch light from 0.262s to 15.73s, or enabled indefinitely, allowing the user to keep the led on as long as a movie is being recorded. flash mode can also be enabled either using the serial interface or by logic control using the torchen or flashen inputs. see the description of the flash_en register for more information about programming the fled enable behavior. flash mode provides a limited- duration light pulse for camera functions. in flash mode, the time duration is limited by an internal timer (flash_ tmr_dur[3:0]). see the flash safety timer section for greater detail on this function. the output current in flash mode is programmable from 23.436ma to 750ma. the settings above 625ma are allowed only if flednum = 0. if both flash and torch modes are enabled at the same time, flash mode is assigned with higher priority. once the flash event is done, the current regulator will then return to torch mode, if this mode is still enabled via software. when the flash led current ramps up via (1) toggle flashen or torchen pins; (2) set torch_fled_en or flash_fled_en bits; (3) set torch_i or flash_i register values from a lower value to a higher value; atypi - cal 12.5ma/s of di/dt rate is applied on the flash led current during the current transition. figure 6. functional diagram for charger reverse boost converter and current sources MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 31 pwm boost converter registers and control logic flash timer torch timer byp adaptive fixed control chglx pgnd sys torchen flashen in_fled fled2 750ma dmos20 130m ? 750ma sys fled1 MAX77829 downloaded from: http:///
flash mode in flash mode, each led current source provides from 23.436ma to 750ma of output current. flash mode can be enabled by driving flashen or torchen high or through the serial interface, depending on register set - tings. flash duration is also programmable through the serial interface. flashen/torchen the flashen or torchen logic inputs or the serial interface can enable/disable the fled_ current regulator in flash mode and in torch mode. if the fled is enabled for both torch and flash mode at the same time, flash mode has priority. once the flash safety timer expires, the current regulator then returns to torch mode. if the safety timer is disabled, torch mode current continues until disabled through the serial interface. configuring how the led responds to flashen or torchen is accomplished by setting bits in the flash_ en register. flash safety timer the flash safety timer is activated any time flash mode is enabled. the flash safety timer, programmable from 62.5ms to 1000ms via serial interface, limits the dura - tion of flash mode to the programmed flash safety timer duration. this timer can be configured to operate either as a one-shot timer or maximum flash duration timer. in one-shot mode, the flash function is initiated on the rising edge of flashen, torchen, or the serial register bits and terminated based on the programmed value of the safety timer (see figure 7 ). in maximum flash timer mode, flash function remains enabled as long as flashen, torchen, or the serial register command is high, unless the pre-programmed safety timer times out (see figure 8 ). once flash mode is disabled, by the flashen or torchen logic inputs, register command, or flash safety timer, the flash must be off for a minimum flash debounce timer (500s C 600s), before it can be reiniti - ated (see figure 11 ). this prevents spurious events from re-enabling flash mode. this time is described in the electrical characteristics table as the flash safety timer reset inhibit period. figure 7. one shot flash timer mode figure 8. maximum flash timer mode MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 32 one-shot flash timer flashen or flash_fledx_en = 11 one-shot flash timer maximum flash timer maximum flash timer flashen or flash_fledx_en = 11 downloaded from: http:///
torch mode in torch mode, the led current source provides from 11.72ma to 3187.5ma of output current for each chan - nel. torch mode is enabled through the torchen or flashen inputs or through the serial interface. torch mode duration is programmable through the serial inter - face, and can be programmed to remain on indefinitely. enabling torch mode the current sources in torch mode is independently enabled either through the torchen or flashen inputs or through the serial interface as programmed by the torch_fled_en bits in the flash_en register. if flash mode and torch mode are enabled at the same time, flash mode is given the higher priority. torch safety timer the torch safety timer is activated any time torch mode is enabled and the torch safety timer disable bit is set to 0. the torch safety timer, programmable from 262ms to 15.7s via the serial interface, limits the duration of torch mode to the programmed torch safety timer duration. this timer can be configured to operate either in one-shot timer or maximum torch duration timer. in one-shot mode, the torch function is initiated on the rising edge of the torch_fled_en register bit or torchen or flashen inputs and terminated based on the programmed value of the safety timer (see figure 10 ). in maximum torch timer mode, torch function remains enabled as long as torch_fled_en is a 11 or torchen or flashen is held high, unless the preprogrammed safety timer times out (see figure 11 ). figure 9. flash debounce timer figure 10. one shot torch timer mode figure 11. maximum torch timer mode MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 33 flashen flash enable debounce timer torchen or torch_fledx_en = 11 one shot torch timer one-shot torch timer maximum torch safety timer torchen or torch_fledx_en = 11 maximum torch safety timer downloaded from: http:///
the torch safety timer can be disabled by setting the torch safety timer disable bit to 1. in this case, the fleds will stay lit in torch mode until the enable command (torchen, flashen, or serial interface) is deasserted, or flash mode is initiated (since flash mode has higher priority than torch mode). maxflash function note that maxflash will detect a drop on v sys and not v batt . during high load currents of a battery cell, the voltage will momentarily drop due to internal esr of the bat - tery, together with serial impendence form the battery to the load. for equipment requiring a minimum voltage for stable operation, the esr of the battery needs to be calculated in order to estimate maximum current that can be drawn from the battery without making the cell volt - age drop below this critical threshold. if this is not done, the power-down voltage will have to be set artificial high, reducing run time of the battery-operated equipment. for applications like camera flash, movie light, or torch light the esr of the system needs to be measured to calculate the maximum current that can be consumed by the flash to insure that at the end of the flash the battery voltage has not dropped below the minimum required bat - tery voltage for the remaining system. since the esr of a battery cell is dependent on load current, temperature, age of cell, and other parameters this esr measurement has to be done during the start of each event in order to ensure that the current esr of the battery cell is correct. figure 12. voltage drop due to battery esr figure 13. using esr calculation to insure minimum battery voltage at the end of flash/torch event normal case MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 34 battery voltage time voltage drop due to esr of battery pack load current current critical minimum vbatt threshold battery voltage time flash/torch current esr calculation changed flash/movie current to ensure minimum vbatt at the end of flash/torch event downloaded from: http:///
in most cases, the camera flash is triggered by the cam - era module itself. therefore, the esr measurement of the battery has to be measured in real time during the initial flash event. since most systems contain many complex functions that are operated independent of each other, the current load might change during the flash/torch duration. if another application within the system starts significantly drawing more current during the flash/torch dura - tion, this can cause the battery voltage to drop below the minimum required battery voltage for the system, hence causing spurious events. on the other hand, if an application is going from a high- current mode to a lower current mode during the flash/ torch event, the battery voltage at the end of the flash/torch duration will be above the minimum bat - tery voltage. this means that the actual flash/torch current could have been set higher for the remaining duration, allowing highest possible output current to be utilized. figure 14. using esr calculation to ensure minimum battery voltage at the end of flash/torch event, with an additional load event during the flash/torch event figure 15. using esr calculation to ensure minimum battery voltage at the end of flash/movie event with load release during flash/movie event MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 35 critical minimum vbatt threshold battery voltage time flash/torch current esr calculation changed flash/movie current to insure minimum vbatt at the end of flash/torch event increase in current drain from battery by other application in the system critical minimum vbatt threshold battery voltage time flash/torch current esr calculation changed flash/movie current to insure minimum vbatt at the end of flash/torch event reduction in current drain from battery by other application in the system downloaded from: http:///
to avoid having to measure the esr of the battery cell and still achieve the goal of insuring that the battery voltage does not drop below a predefined threshold, an alternative circuit can be used. during a flash/torch event, the input voltage of the device is monitored (input kelvin-connected to the bat - tery cell, referred to as v batt ). if the input voltage drops below a predefined threshold, referred to as maxflash_ th, this is an indication that the flash/torch event is drawing more current than the battery can support. as a reaction to this event, the current regulator driving the flash/torch will reduce output current in one step. this will reduce the input current, hence reducing the cur - rent drawn from the battery. since the battery current is now reduced, v batt will start to rise due to the internal esr of the battery cell.the current regulator will then implement a user-defined delay, referred to as t lb_tmr_f , for falling edge detection and t lb_tmr_r for rising edge detection. the v batt is then sampled again and compared to the maxflash_th. if v batt is still below this maxflash_th threshold the current regulator will reduce output current once again to insure that minimum v batt is available for the remain - ing of the system. if v batt is above the maxflash_th threshold plus a user-defined hysteresis, referred to as maxflash_hys, the current regulator will increase the output current one step, only if present output current is less than user-defined output current. if the maxflash_ hys event is set to 000 then the flash current will only be reduced as a result of the low system voltage regard - less if the voltage recovers again. the led current is not allowed to increase again. this will continue for the entire duration of the flash/ torch event, ensuring that the flash/torch output current is always maximized for the specific operation conditions. open/short protection the flash module monitors the fled voltage to detect any open or short leds. an open fault is detected when the voltage on fled rises above v byp C 30mv (typ) for 8ms (typ), and short fault is detected when the voltage on fled drops below 1.0v (max) (referenced to gnd) for 1ms (typ). the fault detection provides a continuous monitor of the current regulators status. once a fault is detected, the current regulator is disabled and the status is latched into the interrupt register bit. this allows the processor to determine the operating condition of the MAX77829. depending on the state of the interrupt mask bits, the MAX77829 can pull down on the int pin when the flash open/short interrupt occurs. figure 16. block diagram of maxflash function MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 36 in current regulator iout_max down lb_th up lb_hys lb_th inhibit timer inhibit timer t lb_tmr downloaded from: http:///
safeout ldo the safeout ldo is a linear regulator that provides an output voltage of 3.3v, 4.85v, 4.9v, or 4.95v and can be used to supply low voltage-rated usb systems. the safeout linear regulator turns on when v chgin 3.2v and sfout_en = logic high (from muic), regardless of charger enable or detbat . safeout is disabled when chgin is greater than the overvoltage threshold (5.90v typ). the safeout ldo integrate high-voltage mosfet to provide 20v protection at their inputs, which are internally connected to the charger input at chgin. safeout is default on at 4.9v. figure 17. example 1 of maxflash function operationfigure 18. example 2 of maxflash function operation MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 37 maxflash_th battery voltage time flash/torch current maxflash_th + maxflash_hys t lb_tmr_f t lb_tmr_f maxflash_th + maxflash_hys reduction in battery current caused by other system battery voltage time flash/torch current i max maxflash_th t lb_tmr_f t lb_tmr_f t lb_tmr_r downloaded from: http:///
wled backlight driverstep-up converter the MAX77829 led boost converter operates from a 2.5v to v sysovlo input supply. due to duty-cycle limita - tions, full output power is only available for input voltages > 2.8v. for low input voltages (2.5v to 2.8v), maximum led output current is available as shown in table 6 . the MAX77829 led boost converter utilizes a peak- current limited architecture. in the event of a serious over - load, where the converter is operating at its current limit for 16ms, an interrupt is generated, and the processor can determine the appropriate course of action. figure 19. functional diagram for wled boost converter and current source table 6. maximum led output current MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 38 wledlx wled1 wledpwm ovpflt ledbst converter with pwm dimming, programmable led current, programmable switching frequency, and fixed voltage operation ovp switching frequency control wledpgnd + - wledout filtdim 150pf 8 m? ledpwmen vsys wledgnd *maximum leds = 10 for one string two 8 for two string wled2 led_en ledfosc led[11:0] leden low-power oscillator MAX77829 ovp v sys 2 strings of 8 2 strings of 6 1 string of 10 1.47mhz 2.2mhz 1.47mhz 2.2mhz 1.10mhz 733khz 3.0v 24.9ma 24.9ma 24.9ma 24.9ma tbd tbd 2.9v 24.9ma 21ma 24.9ma 24.9ma tbd tbd 2.8v 24.9ma 17ma 24.9ma 24.9ma tbd tbd 2.7v 23ma 14ma 24.9ma 24.9ma tbd tbd 2.6v 20ma 11ma 24.9ma 24.9ma tbd tbd 2.5v 18ma 8ma 24.9ma 21ma tbd tbd downloaded from: http:///
the step-up converter switches at a fixed frequency of 2.2mhz to allow the use of small external components. lower switching frequency can be selected through the serial interface to provide higher efficiency and/or avoid noise-sensitive frequency bands. overvoltage protection the MAX77829 is protected against open-circuited led strings. in the event that the led string is open, and the step-up converter is enabled, the wledout pin senses the output voltage of the step-up converter, and regulates the step-up output voltage at the ovp threshold. an inter- rupt (if unmasked) is generated when the step-up con - verter reaches the ovp threshold. to optimize efficiency for the number of wleds used, the ovp threshold is programmable via wledovp bit in wledbstcntl1 register. 28v (max) ovp setting is ideal for supporting up to 8 wleds in series while the 35v (max) ovp setting is needed for supporting up to 10 wleds in series. current sources the MAX77829 provides a low-side current source with 8-bit resolution for programming the led current. a single register programs the output current in both sources. both current sources can be programmed to respond to, or ignore, the wledpwm dimming input with a single bit. the MAX77829 current source features a low-dropout voltage, increasing overall efficiency. when driving the maximum number of series leds, the current sources may enter dropout when the led current is programmed near the maximum value. in this case, the current sources regulates with a 100mv (typ) voltage drop, and provide as much current as allowed by the forward voltage of the leds. setting the current limit the two wled strings feature linear dimming with 8-bit resolution (97.656a per lsb). in addition to the internal led current control offered through the MAX77829 step-up converter, an external pwm signal may be applied to the wledpwm input for content-adaptive brightness control. the wledpwm input accepts signals with frequency between 5khz and 60khz, although optimal performance (minimized led current ripple) is attained with pwm frequencies 15khz. the wledpwm input linearly decreases the led cur - rent in strings 1 and 2 and is enabled through the serial interface. wled1 and wled2 each have individual current sources, and both strings or any individual string may be enabled at any time. wled1 and wled2 share a common current setting register, so strings 1 and 2 always have the same led current, if enabled. mismatched led strings can also be supported by the MAX77829. in the event that led strings with different led count are being powered at the same time, the string with the fewest number of leds will see a higher volt - age drop across the current driver causing higher power consumption. the wled_ current sources provide up to 24.9ma for powering the led backlight. under certain operating con - ditions, such as when powering the maximum number of leds in series, the wled_ current sources operates in a dropout condition, in which 24.9ma may no longer be provided to the led string. enabling cabc dimming (wledpwm input) the MAX77829 supports a cabc dimming signal from the processor to linearly decrease the backlight inten - sity based on the video signal content. the wledpwm input accepts a pwm signal in the 5khz to 60khz range, with optimal performance (minimized led current ripple) attained for pwm dimming frequency > 15khz. the wledpwm signal is internally rc filtered (corner fre - quency 500hz), and is then used to decrease the refer - ence voltage to the current dac for strings 1 and 2. two bits in boost converter control register 1 (ledpwm1en and ledpwm2en) independently program strings 1 and 2 to respond to or ignore the wledpwm signal. if one of the current sources (wled1 or wled2) is disabled, this current source ignores the wledpwm signal. in the event that a 0% duty cycle is applied to the wledpwm input, the converter does not shut down, but instead continues to regulate the wledout voltage. the output current at the wled_ pins is close to zero. top system management main bias the main bias includes voltage and current references for all circuitry that runs from the v sys node. it includes a 0.3% accurate voltage reference that is used by various blocks. the current bias is generated from the reference voltage and trimmed to be within 1.5% and is zero-tc. the current bias is converted to a voltage to route to other blocks. the v ref block generates a 1.25v zero-tc reference voltage. i bias takes v ref as input and generates a v ibias voltage that will track rph variation and tc. instead of generating a current output, a bias voltage for current is generated to be distributed to different blocks. MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 39 downloaded from: http:///
it saves the number of top level routing lines for bias cur - rent at the expense of requiring a bias current generation circuit, generating current as v ibias /rph. system faults the MAX77829 monitors the system for the following faults: sys undervoltage lockout sys overvoltage lockout sys low threshold detection thermal shutdown sys faults the system monitors the sys node for undervoltage, overvoltage, and low threshold events. the following describes the ic behavior if any of these events is to occur. the sys low threshold detection is configurable via registers. sys undervoltage lockout prevents the regulators from being used when the input voltage is below the operating range. when the voltage from sys to gnd (v sys ) is less than the undervoltage lockout threshold (v sysuvlo ), the MAX77829 enters its global shutdown state. sys overvoltage lockout is a fail-safe mechanism and pre - vents the regulators from being used when the input volt - age is above the operating range. the absolute maximum ratings state that the sys node withstands is up to 6v. the sys ovlo threshold is set to 5.3v (typ) C ideally v sys should not exceed the battery charge termination thresh - old. systems must be designed such that v sys never exceeds 4.8v (transient and stead-state). if the v sys should exceed v sysovlo during a fault, the MAX77829 enters its global shutdown state. when v sys voltage falls below its low threshold (v sysl ), the MAX77829 initiates a lowsys interrupt. the low- sys detection circuitry is enabled by default but can be disabled using the lsen bit to reduce current consump - tion. v sysl is configurable using lsdac register bits. choose v sysl based on the system requirements and battery capacity. the v sysl hysteresis (v lshyst ) is configurable using lhyst register bits. choose v lshyst based on your system peak currents and battery impedance. v lshyst should be set sufficiently high to avoid oscillation in and out of the low-sys state due to system peak currents. since the main battery is typically connected to the sys node (through the internal batt to sys switch), this cir - cuit also functions as a low batt comparator. thermal fault the MAX77829 has one centralized thermal circuit for sensing die temperature. if temperature increases above 165c (t shdn ) a thermal shutdown event occurs and the MAX77829 enters its global shutdown state. in addition to the 165c threshold, interrupts are generat - ed when the die temperature reaches 120c and 140c. figure 20. v sys fault monitor functional block diagram MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 40 v sysuvlo v sysovlo low-sys dac v sys l low-sys dac register (lsdac) low-sys hysteresis register (lshyst) global shutdown sysovlo enable v sys lowsys sys overvoltage lockout sys undervoltage lockout sysuvlo lsen downloaded from: http:///
there is a 15c thermal hysteresis. after thermal shut - down, if the die temperature cools by 15c, the thermal shutdown bus is deasserted and dvdd ldo can be enabled again. the main battery charger has an independent thermal control loop which will not cause thermal shutdown. in the event that the charger thermal overload occurs, only the charger will turn off. shutdown events the MAX77829 has a por bus that goes to all blocks except the fuel gauge. the por signal turns off these blocks and resets their registers to a default state under the following conditions: sys undervoltage lockout sys overvoltage lockout overtemperature fault (165c) - this signal has hys - teresis, if the die temperature hits 150c, this signal is deasserted. this should not cause a turn-on event; turn-on events are listed in the thermal fault sec- tion. in other words, this signal is latched. manual reset ( mrst pulled low for 7s default). i 2 c interface the i 2 c serial bus consists of a bidirectional serial-data line (sda) and a serial-clock input (scl). the ic is a slave-only device, relying upon a master to generate a clock signal. the master initiates data transfer to and from the ic and generates scl to synchronize the data transfer. i 2 c is an open-drain bus. both sda and scl are bidi - rectional lines, connected to a positive supply voltage through a pullup resistor. they both have schmitt triggers and filter circuits to suppress noise spikes on the bus to assure proper device operation. a bus master initiates communication with the ic as a slave device by issu - ing a start condition followed by the ic address. the ic address byte consists of 7 address bits and a read/ write bit (r/ w ). after receiving the proper address, the ic issues an acknowledge bit by pulling sda low dur - ing the ninth clock cycle. figure 21 shows the i 2 c slave addresses for each functional block. figure 21. i 2 c state diagram MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 41 i 2 c address address: 0xcc/cdh, 0x6c/6dh, 0x90/91h i 2 c disabled i 2 c enabled reset = high reset = low start condition stop condition any state except disabled any state beyond the assigned repeated start condition pmic (charger, flash led driver) (cc/cdh) wled backlight, motor driver (0x91/0x91h) downloaded from: http:///
i 2 c bit transfer each data bit, from the most significant bit to the least significant bit, is transferred one by one during each clock cycle. during data transfer, the sda signal is allowed to change only during the low period of the scl clock and it must remain stable during the high period of the scl clock ( figure 22 ). i 2 c start and stop conditions both scl and sda remain high when the bus is not busy. the master signals the beginning of a transmission with a start (s) condition by transitioning sda from high to low while scl is high. when the master has finished communicating with the ic, it issues a stop (p) condition by transitioning sda from low to high while scl is high. the bus is then free for another transmission ( figure 23 ). both start and stop conditions are generated by the bus master. figure 22. i 2 c bit transfer figure 23. i 2 c start and stop conditions figure 24. i 2 c acknowledge MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 42 scl sda start condition (s) stop condition (p) data line stable data valid data allowed to change sda scl start condition stop condition sda output from transmitter sda output from receiver scl from master 1 2 8 9 not acknowledge acknowledge clock pulse for acknowledgement d7 d6 d0 start condition downloaded from: http:///
figure 25. master transmits (write mode) figure 26. master reads register data without setting register address (read mode) MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 43 1 s numberof bits r/ w slave address 7 0 1 8 register pointer 1 1 8 data 1p 1 slave to master master to slave legend a) writing to a single register with the write byte protocol 1s numberof bits r/ w slave address 7 0 1 8 register pointer x 1 a 1 8 data x 1 b) writing to multiple registers 8 data x + n - 1 1 8 data x + n 1 number of bits p 8 data x + 1 1 a a a a a a a a 1 s number of bits slave address 7 0 1 8 register pointer 1 11 7 slave address 11 slave to master master to slave legend a. reading a single register 1s number of bits slave address 7 0 1 8 register pointer x 1 a 1 1 7 slave address 1 b. reading multiple registers 8 data x+1 1 8 data x+n-1 1 number of bits 8 data x 1 r/ w r/ w r/ w r/ w a a a a a a sra 1 8 data 1p 1 a a 1 1 sr 8 data x+n 1 1 a p downloaded from: http:///
i 2 c acknowledge the number of data bytes between the start and stop conditions for the transmitter and receiver are unlimited. each 8-bit byte is followed by an acknowledge bit. the acknowledge bit is a high-level signal put on sda by the transmitter during which time the master generates an extra acknowledge related clock pulse. a slave receiver which is addressed must generate an acknowledge after each byte it receives. also a master receiver must gener - ate an acknowledge after each byte it receives that has been clocked out of the slave transmitter. the device that acknowledges must pull down the sda line during the acknowledge clock pulse, so that the sda line is stable low during the high period of the acknowl - edge clock pulse (setup and hold times must also be met). a master receiver must signal an end of data to the transmitter by not generating an acknowledge on the last byte that has been clocked out of the slave. in this case, the transmitter must leave sda high to enable the master to generate a stop condition. multibutton manual reset mrst is the manual reset input for hardware reset. falling edge of mrst and minimum 7s (default) low initi - ate the automatic power reboot. the debouncing time is programmable ranging from 3s to 10s (with 1s per step). after the debouncing timer expires, the reset output asserts and all the MAX77829 registers return to their default values. the reset output is intended to reset the host systems main pmic and/or applications processor in case they do not already have manual reset inputs of their own. when the manual reset feature is not required, pull mrst above logic-high input. int the MAX77829 interrupts indicate to the application pro - cessor that the status of the MAX77829 has changed. int asserts low whenever one or more interrupts are toggled, and those interrupts are not masked. the application processor may read the interrupts in two steps. first, the ap reads the intsrc register. this is a read-only register indicating which functional block is generating the inter - rupt, i.e. charger, flash, or other blocks. depending on the result of the read, the next step is to read the actual inter - rupt registers pertaining to the functional block. for example, if the application processor reads 0x02 from intsrc register, it means the top-level pmic block has an interrupt generated. the next step is to read the int1 register of the pmic functional block. int becomes high (cleared) as soon as the read sequence of the last int_ register that contains an active interrupt starts. all interrupts can be masked to prevent int from being asserted for masked interrupts. a mask bit in the intm register implements masking. the intsrc register can still provide the actual interrupt status of the masked interrupts, but int is not asserted. MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 44 downloaded from: http:///
MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 45 typical application circuit input current limit, aicl, otgilim buck/ boost control mbatt lxchg byp pgchg avl bat+ agnd l chg , 1h dc c bst 0.1f pvl c mbatt 4.7f system load r cs 47m , 1/4w cs supports usb otg, 5v/500ma c dc 2.2f 10 fet_drv mbatrsnsp bat- q4 q5 q6 battery pack max +9.4v operation mbatrsnsn gmi c pvl 10f c avl 10f syss c sys 10f sys avl powers internal circuits sys powers internal circuits bst c byp 4.7f inokb 100k 100k safeout 1f vichg gschg control logic fet driver thermistor /battery detection bat2sys oc scl vio c vio 1f sda intb 2.2k ? mrstb resetb 750ma fled_1 infled c in_fled 4.7f flashentorchen ovp wledlx wled1 wledpwm wledpgnd wledout vsys wledgnd wled2 sysa gnd_a gnd_d 1f thm from byp flash led 750ma fled_2 vsys vio ntc r batoc 5m safeout ldo vio MAX77829 q2 downloaded from: http:///
MAX77829 companion pmic for smartphone and tablet www.maximintegrated.com maxim integrated 46 ordering informationchip information process: cmos package information for the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages . note that a +, #, or - in the package code indicates rohs status only. package drawings may show a different suffix character, but the drawing pertains to the package regardless of rohs status. part temp range pin-package MAX77829ewn+ -40c to +85c 56 wlp 0.4mm pitch, 3.64mm x 3.24mm package type package code outline no. land pattern no. 56 wlp w563f3+1 21-1038 refer to application note 1891 downloaded from: http:///
maxim integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim integrated product. no circuit patent licenses are implied. maxim integrated reserves the right to change the circuitry and speciications without n otice at any time. the parametric values (min and max limits) shown in the electrical characteristics table are guaranteed. other parametric values quoted in this data sheet are provided for guidance. maxim integrated and the maxim integrated logo are trademarks of maxim integrated products, inc. ? 2015 maxim integrated products, inc. 47 MAX77829 companion pmic for smartphone and tablet revision history revision number revision date description pages changed 0 12/15 initial r elease for pricing, delivery, and ordering information, please contact maxim direct at 1-888-629-4642, or visit maxim integrateds website at www.maximintegrated.com. downloaded from: http:///

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