www.belling.com.cn 1 pwm or singl-wire dimming, 4-channels wled linear d river BL8581A description the BL8581A is a cmos based white/blue led driver with stand-alone capability. the driver is primarily designed for led backlighting of lcd display powered by li-ion battery with its high efficiency, low standby current and wide range of input supply voltage, the BL8581A is suitable for applications such as portable device display and keypad backlighting. it can realize pwm or single-wire dimming control through en pin. BL8581A has four led channels with msop- 8 or qfn 3x3 -16 package. features 2.7 to 5.5v input range single-wire dimming control with linear 16- steps pwm dimming control led sink current of max. 20ma independent current sink circuit for each led output low standby current high accuracy current match on each channel applications small size color lcd backlights driver mobile phone, portable devien keypad backlights driver typical application
www.belling.com.cn 2 BL8581A marking information product classification BL8581Ace8tr marking led led led led1 11 1 vcc vcc vcc vcc gnd gnd gnd gnd gnd gnd gnd gnd led led led led2 22 2 led led led led4 44 4 led led led led3 33 3 en enen en kb kbkb kb yybnn yybnn yybnn yybnn 1 11 1 2 22 2 3 33 3 4 44 4 8 88 8 7 77 7 6 66 6 5 55 5 top view kb yybzz kb: product code yy: lot no. b: fab code zz: date code product classification BL8581Acjkatr marking led led led led1 11 1 vcc vcc vcc vcc nc ncnc nc nc ncnc nc nc ncnc nc gnd gnd gnd gnd gnd gnd gnd gnd nc ncnc nc nc ncnc nc led led led led3 33 3 led led led led4 44 4 led led led led2 22 2 nc ncnc nc en enen en nc ncnc nc nc ncnc nc 16 1616 16 kba kba kba kba yybnn yybnn yybnn yybnn 1 11 1 5 55 5 9 99 9 2 22 2 3 33 3 15 1515 15 14 1414 14 13 1313 13 12 1212 12 11 1111 11 8 88 8 10 1010 10 7 77 7 6 66 6 4 44 4 top view kba yybzz kba: product code yy: lot no b: fab code zz: date code product classification BL8581Acjkbtr marking led led led led1 11 1 vcc vcc vcc vcc nc ncnc nc nc ncnc nc nc ncnc nc gnd gnd gnd gnd nc ncnc nc nc ncnc nc nc ncnc nc led led led led3 33 3 led led led led4 44 4 led led led led2 22 2 nc ncnc nc en enen en nc ncnc nc nc ncnc nc 16 1616 16 kbb kbb kbb kbb yybnn yybnn yybnn yybnn 1 11 1 5 55 5 9 99 9 2 22 2 3 33 3 15 1515 15 14 1414 14 13 1313 13 12 1212 12 11 1111 11 8 88 8 10 1010 10 7 77 7 6 66 6 4 44 4 top view kbb yybzz kbb: product code yy: lot no b: fab code zz: date code product classification BL8581Acjkctr marking led led led led1 11 1 vcc vcc vcc vcc nc ncnc nc nc ncnc nc nc ncnc nc gnd gnd gnd gnd gnd gnd gnd gnd nc ncnc nc nc ncnc nc led led led led3 33 3 led led led led4 44 4 led led led led2 22 2 nc ncnc nc en enen en vcc vcc vcc vcc nc ncnc nc 16 1616 16 kbc kbc kbc kbc yybnn yybnn yybnn yybnn 1 11 1 5 55 5 9 99 9 2 22 2 3 33 3 15 1515 15 14 1414 14 13 1313 13 12 1212 12 11 1111 11 8 88 8 10 1010 10 7 77 7 6 66 6 4 44 4 top view kbc yybzz kbc: product code yy: lot no b: fab code zz: date code ordering information BL8581A 1 2 3 code description 1 temperature&rohs: c: -40~85 c, pb free rohs std. 2 package type: e8: msop-8 jka: qfn 3x3 C16 jkb: qfn 3x3 C16 jkc: qfn 3x3 C16 3 packing type: tr:tape&reel (standard) pin description name function description led1-led4 rgb or wled cathode connection pin en chip enable and dimming control vcc power supply gnd ground nc not connected absolute maximum rating supply voltage C0.3v to 7v voltage of ledn, en pin C0.3v to 7v maximum junction temperature 125c operating ambient temperature range C40c to 85c storage temperature range C40c to 150c lead temperature (soldering, 10 sec) 260c note: exceed these limits to damage to the device. note: exposure to absolute maximum rating conditions may affect device reliability. recommended operating conditions items min max unit supply voltage range 2.7 5.5 v operating temperature -25 85
www.belling.com.cn 3 BL8581A block diagram shunt shunt shunt shunt regulator regulator regulator regulator led led led led1 11 1 led led led led2 22 2 led led led led3 33 3 en enen en vcc vcc vcc vcc led led led led4 44 4 gnd gnd gnd gnd enable enable enable enable electrical characteristics vcc=3.7v, t a =25 c, no load, input: ven=3.7v. (unless otherwise note d) symbols parameters conditions min typ max unit v il en pin low logic 0.4 v v ih en pin high logic 1.7 v i il en pin low input current -1 m a i ih en pin high input current 1 m a t d pwm dimming control delay time 20 m s t lat latch off time before transient to the new current level (see figure 2) 20 m s t pulse required positive and negative pulse width pulse dimming control 4 20 m s v ledl ledn dropout voltage 100 mv i led ledn sink current 18 20 22 ma d i ledn ledn sink current deviation -3 3 % i q quiescent current 250 400 m a i stby standby supply current ven=0 0.5 m a
www.belling.com.cn 4 BL8581A detailed description BL8581A works with a wide range of supply voltage, from 2.7v to 5.5v. the forward voltage of commercial white/blue led is in the range of 2.9v to 3.5v at a current level of 20ma. proper selection of the led to match the supply voltage can fully utilize the li-ion battery. for example, there is 1% ~ 3 % power left in the li-ion battery when its voltage reaches 3.275v. so a led with a forward voltage value of 3.2v can use up to 99% of the battery power under normal working condition. when the voltage of the battery drops below 3.2v, the current through the led (hence the brightness) starts to decrease. startup sequence BL8581A starts to work only when vcc powered on and the en pin became high after a delay, the delay time is at least 4us. en pin is not allowed to connect to vcc directly or keep it floating. pwm dimming control if the frequency of the pwm signal to the en pin is less than 5khz, the average led current is proportional to the duty cycle of the pwm signal, and the en works as a simple on/off control. a high level turns on and a low shuts down the leds. there is a delay time between the input pwm signal and the output led current waveform, as shown in fig.1, the t d is about 20us. i_led 20ma td=20us on duty td=20us en fig. 1 pwm dimming control single-wire dimming control the leds brightness can also be controlled by the pulses applied to the en pin, refer to the fig. 2. inside the device there is a 4-bit counter connecting to the en pin. the led current can be programmed up to 16 levels depends on the number of rise edges of the input waveform. a high level input (1) with pulse width wider than 20us is regarded as a signal to stop the build-in counter. the time between two wide high levels (more than 20us) is a counting period. when some rise edges occur between two high level pulses of 20us, the equation as shown below can calculate the active pulse number, called code_no. ) 16, ( _ n mod no code = , in the equation, n is the number of rise edges of the input waveform and mod function returns the remainder of n divided by 16. for example, if n=0, 16, or other integral multiple of 16, the mod function returns a value of 0, if n=1, 17 or other integral multiple of 16 plus 1, the mod function returns a value of 1, and so on. the relationship between leds brightness and the code_no is listed as the following table. code no i set /20ma code no i set /20ma 0 0 8 8/15 1 15/15 9 7/15 2 14/15 10 6/15 3 13/15 11 5/15 4 12/15 12 4/15 5 11/15 13 3/15 6 10/15 14 2/15 7 9/15 15 1/15 the frequency of the input pulse should be lower than 100khz, and the width of the high level and low level larger than 4us to prevent false trigger. code_no=1 code_no=4 iset/20ma=15/15 20us 20us en i_le d iset/20ma=12/15 fig. 2 single-wire dimming control
www.belling.com.cn 5 BL8581A typical performanen characteristics quiescent current vs supply current (ta=25) 0 50 100 150 200 250 300 350 3.0 3.5 4.0 4.5 5.0 supply voltage (v) quiescent current (ua) quiescent current vs temperature (vcc=3.7v) 0 50 100 150 200 250 300 350 400 450 -40 -20 0 20 40 60 80 100 120 140 temperature () quiescent current (ua) iled vs supply voltage (vcc=3.7v, vledn=3.2v) 10 12 14 16 18 20 22 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4.0 4.1 4.2 supply voltage (v) iled (ma) iled vs ledn dropout voltage (vcc=3.7v) 0 5 10 15 20 25 0.01 0.1 1 10 ledn dropout voltage (v) led current (ma) iled vs temperature (vcc=3.7v) 19.7 19.8 19.8 19.9 19.9 20.0 20.0 20.1 20.1 20.2 20.2 -50 -25 0 25 50 75 100 125 temperature () iled (ma) led current vs code_no 0 4 8 12 16 20 0 2 4 6 8 10 12 14 16 code_no led current(ma)
www.belling.com.cn 6 BL8581A package information package msop-8 devices per reel 3000pcs unit mm package specification symbol dimension (mm) symbol dimension (mm) min nom max min nom max a - - 1.10 d 2.90 3.00 3.10 a1 0.05 0.15 e 4.70 4.90 5.10 a2 0.75 0.85 0.95 e1 2.90 3.00 3.10 a3 0.30 0.35 0.40 e 0.65bsc b 0.29 - 0.38 l 0.40 - 0.70 b1 0.28 0.30 0.33 l1 0.95bsc c 0.15 - 0.20 q 0 - 8 c1 0.14 0.152 0.16
www.belling.com.cn 7 BL8581A package information package qfn3x3-16 devices per reel 3000 unit mm
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