ws4508e 6 00ma , single li - ion battery charger descriptions the ws4508e is a complete constant - current / constant voltage linear charger for single cell lithium - ion batteries. no external sense resistor is needed, and no blocking diode is required due to the internal mosfet architecture. thermal feedback regulates the charge current to limit the die temperature during high power o peration or high ambient temper ature. the charge voltage is fixed at 4.2v, and the charge current can be programmed externally w ith a single resistor. the ws4508e automatically terminates the charge cycle when the charge current drops to 1/10 the programmed value after the final float voltage is reached. when the input supply (wall adapter or usb supply) is removed, the ws4508e automatically enters a low current state, dropping the batt ery drain current to less than 0.5 ua . the ws4508e can be put into shutdown mo de, reducing supply current to 45 u a (typ.) . the ws4508e is available in a small package with sot - 23 - 5l. standard produc t is pb - free. features ? programmable charge current up to 6 00ma ? over - temperature protection ? under voltage lockout protection ? automatic recharge threshold 4.05v (typ.) ? charge status output pin ? 2.9v trickle charge threshold ? soft - start limits inrush current a pplications ? wireless phone ? mp3/mp4 player ? bluetooth device sot - 23 - 5l pin c onfiguration (top view) 45 0 8 yyww 45 0 8 = device code y y = year ww = week order i nformation device package s hipping ws4508e - 5/tr sot - 23 - 5l 3000 /reel&tape 1 2 3 5 4 chgb gnd bat vcc prog 1 2 3 4 5 1 of 11 4008-318-123 sales@twtysemi.com http://www.twtysemi.com product specification
typical a pplications typical applications w/t led indicate t ypical applications w/t microprocessor detect pin d escription s block diagram pin number pin name function 1 chgb open - drain charge stat us output. when the battery is charging, the chgb pin is pulled low. when the charge cycle is completed or vcc is removed, the chgb is forced high impedance. 2 gnd ground 3 bat charge current output. provides charge current to the battery and regulates the final float voltage to 4.2v. 4 vcc power supply 5 prog charge c urrent setting , c harge c urrent m onitor and s hutdown p in. the charging current is given by i bat = ( 1/r prog )*1000. the chip will be shutdown when prog pin floating v c h g v c c p r o g c h g b b a t g n d 2 k 1 0 u f l i - i o n b a t t e r y w s 4 5 0 8 e 1 2 3 4 5 1 k v c h g v c c p r o g c h g b b a t g n d 2 k 1 0 u f l i - i o n b a t t e r y w s 4 5 0 8 e v i o u p 6 8 0 k 1 2 3 4 5 ma 5 ua va c 1 c 2 c 3 vcc 3 ua to bat 2 . 9 v prog gnd ca chgb r 5 r 4 r 3 0 . 1 v 1 v r 1 r 2 shdnb ta tdie 165 c 1 x 1000 x vcc bat ref 1 . 2 v ws4508e 2 of 11 4008-318-123 sales@twtysemi.com http://www.twtysemi.com product specification v c h g v c c p r o g c h g b b a t g n d 2 k 1 0 u f l i - i o n b a t t e r y w s 4 5 0 8 e 1 2 3 4 5 1 k v c h g v c c p r o g c h g b b a t g n d 2 k 1 0 u f l i - i o n b a t t e r y w s 4 5 0 8 e v i o u p 6 8 0 k 1 2 3 4 5 ma 5 ua va c 1 c 2 c 3 vcc 3 ua to bat 2 . 9 v prog gnd ca chgb r 5 r 4 r 3 0 . 1 v 1 v r 1 r 2 shdnb ta tdie 165 c 1 x 1000 x vcc bat ref 1 . 2 v
absolute maximum r ating s th ermal resistance characteristics note1: surface mounted on fr4 board using 1 in sq pad size, 2 oz cu. note2 : surface mounted on fr4 board using the minimum recommended pad size, 2 oz cu. parameter symbol rating unit supply voltage vcc - 0.3~ 8 v prog voltage v prog - 0.3~vcc v bat voltage v bat - 0.3~ 8 v chgb voltage v chgb - 0.3~vcc v bat pin current i bat 6 00 ma power dissipation C note1 pd 0.5 w power dissipat ion C note2 pd 0.3 w junction temperature tj 150 o c operation temperature top - 45~85 o c storage temperature tsg - 65~125 o c lead temperature (soldering 10s) 260 o c symbol parameter max. unit r ? ja 1 thermal resista nce, junction to ambient C note1 125 o c/w r ? ja 2 thermal resistance, junction to ambient C note2 415 o c/w ws4508e 3 of 11 4008-318-123 sales@twtysemi.com http://www.twtysemi.com product specification
electronics characteristics ( vcc=5v, ta=25 o c , unless otherwise noted) symbol parameter condition min. typ. max. unit i splychrg charge mode supply current r prog =2k 65 0 2 000 ua r prog = 10 k 24 0 2 000 ua i batchrg charge mode battery current r prog =2k 4 50 500 5 50 ma r prog = 10 k 8 0 93 1 10 ma v progchrg prog pin voltage r prog =2k 0.93 1.00 1.07 v r prog = 10 k 0.9 3 1.00 1. 07 v i splystby standby mode supply current charge terminated 1 40 5 00 ua i batstby standby mode battery current ch arge terminated 0 - 2.5 - 6 ua i splyasd shutdown mode supply current v cc typical characteristics (ta=25 o c, unless otherwise noted ) prog pin voltage vs supply volta ge prog pin voltage vs ambient temperature charge current vs prog pin voltage charge current vs supply voltage trickle charge current vs supply voltage trickle voltage vs supply voltage -25 0 25 50 75 100 0.90 0.92 0.94 0.96 0.98 1.00 1.02 1.04 1.06 1.08 1.10 v cc =5v v bat =4v r prog =2k v prog (v) temperature( o c) 4.5 5.0 5.5 6.0 6.5 300 350 400 450 500 550 600 650 700 i bat (ma) v cc (v) v bat =4.0v r prog =2k 4.5 5.0 5.5 6.0 6.5 0.90 0.92 0.94 0.96 0.98 1.00 1.02 1.04 1.06 1.08 1.10 v prog (v) v cc (v) v bat =4.0v r prog =2k 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 i bat (a) v prog (v) v cc =5.0v r prog =2k 4.5 5.0 5.5 6.0 6.5 2.85 2.86 2.87 2.88 2.89 2.90 2.91 2.92 2.93 2.94 2.95 v trikl (v) v cc (v) r prog =2k 4.5 5.0 5.5 6.0 6.5 0 5 10 15 20 25 30 35 40 45 50 r prog =2k r prog =10k v bat (ma) v cc (v) v bat =2.5v ws4508e 5 of 11 4008-318-123 sales@twtysemi.com http://www.twtysemi.com product specification -25 0 25 50 75 100 0.90 0.92 0.94 0.96 0.98 1.00 1.02 1.04 1.06 1.08 1.10 v cc =5v v bat =4v r prog =2k v prog (v) temperature( o c) 4.5 5.0 5.5 6.0 6.5 300 350 400 450 500 550 600 650 700 i bat (ma) v cc (v) v bat =4.0v r prog =2k 4.5 5.0 5.5 6.0 6.5 0.90 0.92 0.94 0.96 0.98 1.00 1.02 1.04 1.06 1.08 1.10 v prog (v) v cc (v) v bat =4.0v r prog =2k 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 i bat (a) v prog (v) v cc =5.0v r prog =2k 4.5 5.0 5.5 6.0 6.5 2.85 2.86 2.87 2.88 2.89 2.90 2.91 2.92 2.93 2.94 2.95 v trikl (v) v cc (v) r prog =2k 4.5 5.0 5.5 6.0 6.5 0 5 10 15 20 25 30 35 40 45 50 r prog =2k r prog =10k v bat (ma) v cc (v) v bat =2.5v
prog pin pull - up current vs prog pin voltage chgb pin current vs chgb pin voltage p rog pin clamp current vs prog pin voltage float voltage vs supply voltage float voltage vs ambient temperature charge current vs battery voltage 4.5 5.0 5.5 6.0 6.5 4.10 4.12 4.14 4.16 4.18 4.20 4.22 4.24 4.26 v float (v) v cc (v) r prog =2k 0 1 2 3 4 5 6 0 2 4 6 8 10 12 14 16 18 20 i chgb (ma) v chgb (v) v cc =5v v bat =4v 2.0 2.1 2.2 2.3 2.4 2.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 v cc =5v v bat =4.3v i prog (ua) v prog (v) 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 -1500 -1200 -900 -600 -300 0 i prog (ua) v prog (v) v cc =5v v bat =4.3v -25 0 25 50 75 100 4.00 4.05 4.10 4.15 4.20 4.25 4.30 4.35 4.40 v cc =5v r prog =2k v float (v) temperature( o c) 2.7 3.0 3.3 3.6 3.9 4.2 4.5 0 100 200 300 400 500 600 i bat ( ma ) v bat ( v ) v cc = 5 v r prog = 2 k -40 o c 25 o c 85 o c ws4508e 6 of 11 4008-318-123 sales@twtysemi.com http://www.twtysemi.com product specification 4.5 5.0 5.5 6.0 6.5 4.10 4.12 4.14 4.16 4.18 4.20 4.22 4.24 4.26 v float (v) v cc (v) r prog =2k 0 1 2 3 4 5 6 0 2 4 6 8 10 12 14 16 18 20 i chgb (ma) v chgb (v) v cc =5v v bat =4v 2.0 2.1 2.2 2.3 2.4 2.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 v cc =5v v bat =4.3v i prog (ua) v prog (v) 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 -1500 -1200 -900 -600 -300 0 i prog (ua) v prog (v) v cc =5v v bat =4.3v -25 0 25 50 75 100 4.00 4.05 4.10 4.15 4.20 4.25 4.30 4.35 4.40 v cc =5v r prog =2k v float (v) temperature( o c) 2.7 3.0 3.3 3.6 3.9 4.2 4.5 0 100 200 300 400 500 600 i bat ( ma ) v bat ( v ) v cc = 5 v r prog = 2 k -40 o c 25 o c 85 o c
trickle charge threshold vs ambient temperature trickle charge current vs ambient temperature recharge voltage threshold vs ambient temperature charge current vs ambient tempera ture -50 -25 0 25 50 75 100 30 32 34 36 38 40 42 44 46 48 50 i trikl (ma) temperature( o c) v cc =5v v bat =2.5v r prog =2k -25 0 25 50 75 100 2.80 2.82 2.84 2.86 2.88 2.90 2.92 2.94 2.96 2.98 3.00 v cc =5v r prog =2k v trikl (v) temperature( o c) -25 0 25 50 75 100 3.80 3.85 3.90 3.95 4.00 4.05 4.10 4.15 4.20 v cc =5v r prog =2k v rechrg (v) temperature( o c) -30 0 30 60 90 120 150 180 0 100 200 300 400 500 600 i bat (ma) temperature( o c) v cc =5v v bat =4v r prog =2k ws4508e 7 of 11 4008-318-123 sales@twtysemi.com http://www.twtysemi.com product specification -50 -25 0 25 50 75 100 30 32 34 36 38 40 42 44 46 48 50 i trikl (ma) temperature( o c) v cc =5v v bat =2.5v r prog =2k -25 0 25 50 75 100 2.80 2.82 2.84 2.86 2.88 2.90 2.92 2.94 2.96 2.98 3.00 v cc =5v r prog =2k v trikl (v) temperature( o c) -25 0 25 50 75 100 3.80 3.85 3.90 3.95 4.00 4.05 4.10 4.15 4.20 v cc =5v r prog =2k v rechrg (v) temperature( o c) -30 0 30 60 90 120 150 180 0 100 200 300 400 500 600 i bat (ma) temperature( o c) v cc =5v v bat =4v r prog =2k
operation info r mation s the ws4508e is a single cell lithium - ion battery charger using a constant - current / constant - voltage algo rithm. it can deliver up to 0. 6 a of charge current (using a good thermal pcb layout) with a final float vo ltage accuracy of 1%. the ws4508e includes an internal p - channel power mosfet and thermal regulation circuitry. no blocking diode or external current sense resistor is required; thus, the basic charger circuit requires only two external components. furthe rmore, the ws4508e is cap able of operating from a usb power source. normal c harge c ycle a charge cycle begins when the voltage at the vcc pin rises above the uvlo threshold level and a 1% program resistor is connected from the prog pin to ground or when a battery is connected to the charger output. if the bat pin is less than 2.9v, the charger enters trickle charge mode. in this mode, the ws4508e supplies approximately 1/10 the programmed charge current to bring the battery voltage up to a safe level for f ull current charging. when the bat pin voltage rises above 2.9v, the charger enters constant - current mode, where the programmed charge current is supplied to the battery. when the bat pin approaches the final f loat voltage, the ws4508e enters constant - vol tage mode and the charge current begins to decrease. t he charge cycle ends w hen the prog voltage is less than 100mv . programming charge current the charge current is programmed using a single resistor from the prog pin to ground. the battery charge curre nt of constant current mode is 1000 times the current out of the prog pin. the program resistor and the charge current of constant current are calculated using the following equations: i chg = (1 v /r prog )*1000 charge t ermination a charge cycle is terminated when th e charge current falls to 1/10 of the programmed value after the final float voltage is reached. this condition is detected by using an internal, filtered comparator to monitor the prog pin. when the prog pin voltage fal ls below 100mv for longer th an t term (typically 1ms), charging is terminated. the charge curren t is latched off and the ws4508e enters standby mode, where the i nput supply current drops to 1 4 0u a. (note: c c /10 termination is disabled in trickle charging mode and thermal limiting modes ). when charging, transient loads on the bat pin can cause the prog pin to fall below 100mv for short periods of time before the dc char ge current has dropped to 1/10 of the programmed value. the 1ms filter time (t term ) on the termination comparator ens ures that transient loads of this nature do not result in premature charge cycle termination. once the average c harge current drops below 1/10 of t he programmed value, the ws4508e terminates the charge cycle and ceases to provide any current through the ba t pin , the chip will be put into standby mode . in this state, all loads on the bat pin must be supplied by the battery . the ws4508e constantly monitors the bat pin voltage in standby mode. if this voltage drops below the 4.05v recharge threshold (v rechrg ), another charge cycle begins and current is once again supplied to the battery. the state diagram of a typi cal charge cycle is as below: t r i c k l e c h a r g e m o d e c h a r g e c u r r e n t : c c / 1 0 c h g b : p u l l d o w n c o n s t a n t - c u r r e n t m o d e c h a r g e c u r r e n t : c c c h g b : p u l l d o w n c o n s t a n t v o l t a g e m o d e c h a r g e c u r r e n t : d e c r e a s e c h g b : p u l l d o w n s t a n d b y m o d e c h a r g e c u r r e n t : 0 a i c c : 1 3 0 u a i b a t : - 2 . 5 u a c h g b : h i g h i m p e d a n c e s h u t d o w n m o d e c h a r g e c u r r e n t : 0 a i c c : 5 0 u a i b a t : - 1 u a c h g b : h i g h i m p e d a n c e b a t < 2 . 9 v 4 . 2 < b a t < 2 . 9 v b a t > = 4 . 2 v p r o g < 1 0 0 m v p r o g f l o a t i n g o r u v l o p r o g r e c o m m e n d o r u v l o s t o p p o w e r o n b a t < 4 . 0 5 v ws4508e 8 of 11 4008-318-123 sales@twtysemi.com http://www.twtysemi.com product specification t r i c k l e c h a r g e m o d e c h a r g e c u r r e n t : c c / 1 0 c h g b : p u l l d o w n c o n s t a n t - c u r r e n t m o d e c h a r g e c u r r e n t : c c c h g b : p u l l d o w n c o n s t a n t v o l t a g e m o d e c h a r g e c u r r e n t : d e c r e a s e c h g b : p u l l d o w n s t a n d b y m o d e c h a r g e c u r r e n t : 0 a i c c : 1 3 0 u a i b a t : - 2 . 5 u a c h g b : h i g h i m p e d a n c e s h u t d o w n m o d e c h a r g e c u r r e n t : 0 a i c c : 5 0 u a i b a t : - 1 u a c h g b : h i g h i m p e d a n c e b a t < 2 . 9 v 4 . 2 < b a t < 2 . 9 v b a t > = 4 . 2 v p r o g < 1 0 0 m v p r o g f l o a t i n g o r u v l o p r o g r e c o m m e n d o r u v l o s t o p p o w e r o n b a t < 4 . 0 5 v
charge s tatus i ndicator (chgb) th e charge status output indicator is an open drain circuit. t he indicator has two different states: pull - down (~10ma), and high impedance. the pull - down state indicates that the ws4508e is in a c harge cycle . high impedance indicates that the charge cycle is complete . the chgb also can be used to detect the charge states by a mi croprocessor with a pull - up resistor . s hutdown mode at any point in the charge cycle, the ws4508e can be put into shutdown mode by removing rprog thus floating the prog pin. this reduces the battery drain current to less than 0.5 u a and the supply current to less than 7 0 u a. a new charge cycle can be initiated by reconnecting the program resistor. below is a recommend application . the ws4508e also be put into shutdown mode when vcc voltage down to uvlo threshold . i n this state, the ch gb pin is high impedance state . the chgb pin is also in a high impedan ce state if the charge cycle is completed . automatic r echarge once the charge cycle is terminated, the ws4508e continuously monitors the voltage on the bat pin using a comparator with a 2 ms filter time (t rechrg ). a charge cycle restarts when the battery voltage falls below 4.05v (which corresponds to approximately 80% to 90% battery capacity). this ensures that the battery is kept at or near a fully charged condition and eliminates the nee d for period ic charge cycle initiations. chgb output enters a pull - down state during recharge cycles. v c h g v c c p r o g c h g b b a t g n d 2 k 1 0 u f l i - i o n b a t t e r y w s 4 5 0 8 e v i o u p 6 8 0 k 1 2 3 4 5 ws4508e 9 of 11 4008-318-123 sales@twtysemi.com http://www.twtysemi.com product specification v c h g v c c p r o g c h g b b a t g n d 2 k 1 0 u f l i - i o n b a t t e r y w s 4 5 0 8 e v i o u p 6 8 0 k 1 2 3 4 5
application information s stability c onsiderations the constant - voltage mode feedback loop is stable without an output capacitor provided a battery is connected to the charger output. with no battery present, an output capacitor is recommended to reduce ripple voltage. when using high value, low esr ceramic capacitors, it is recommended to add a 1 ? resistor in series with the capacitor. no series resistor is needed if tantalum capacitors are used. in constant - current mode, the prog pin is in the feedback loop, not the battery. the constant - current mode stability is affected by the impedance at the prog pin. with no additional capacitance on the prog pin, the charger is stable with prog ram resistor values as high as 1 0 k ? . however, additional capacitance on this node reduces the maximum allowed program resistor thus it should be avoided. thermal l im it an internal thermal feedback loop reduces the programmed charge current if the die temperature attempts to rise above a preset value of approximately 1 50 c. t his feature protects the ws4508e from excessive temperature and allows the user to push the lim its of the power handling capability of a given circuit board with out risk of damaging the ws4508e . the charge current can be set according to typical (not worst - case) ambient temperature with the assurance that the charger will automatically reduce the cu rrent in worst - case conditions. power d issipation the conditions that cause the ws4508e to reduce charge current through thermal feed - back can be approximated by considering the power dissipated in the ic. nearly all of this power dissipation is g enerated by the internal mosfet . this is calculated to be approximately: p d = (vcc - v bat )*i bat it is im portant to remember that ws4508e applications do not be designed for worst - case thermal conditions since the ic will automatically reduce power dissipat ion when the junction temperature reaches approximately 1 50 c (constant temperature mode) . vcc b ypass c apacitor many types of capacitors c an be used for input bypass , however, caution must be exercised when using multilayer ceramic capacitors. because of the self - resonant and high q characteristics of some types of ceramic capacitors, a 1uf/16v ceramic capacitor is recommended for this bypass capacitor. d ue to a high voltage transient will be generated under some start - up conditions, such as connecting the charger input to a live power source. charge c urrent s oft - s tart the ws4508e includes a soft - start circuit to minimize the inrush current at the start of a charge cycle. when a charge cy cle is initiated, the charge current ramps from zero to the full - scale current over a period of approximately 50s. this has the effect of minimizing the transient current load on the power supply during start - up. ws4508e 10 of 11 4008-318-123 sales@twtysemi.com http://www.twtysemi.com product specification
package outline dimensions sot - 23 - 5 l sym bol dimensions in millimeters min. max. a 1.050 1.250 a1 0.000 0.100 a2 1.050 1.150 b 0.300 0.500 c 0.100 0.200 d 2.820 3.020 e 1.500 1.700 e1 2.650 2.950 e 0.950( basic ) e1 1.800 2.000 l 0.300 0.600 0 o 8 o ws4508e 11 of 11 4008-318-123 sales@twtysemi.com http://www.twtysemi.com product specification
|
