View ADP2291-15_8187423.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

compact, 1.5 a linear charger for single-cell li+ battery adp2291 rev. a in for m a t i o n f u r n is h e d b y an al o g d e vice s is b e li ev e d to b e accu ra te a n d reli abl e . h o w e v e r , n o r e sp o n sibi lit y is as s u m e d by an al o g d e vices fo r i t s u s e , n o r fo r a n y i n fr i n g e m e nts of pate n t s or ot h e r r i g h ts o f th ir d par t ies th a t m a y r e su l t f r o m i t s use . s p e c i f ica t io n s su bj e c t t o c h an g e w i th o u t n o ti c e . n o l i c e n s e i s g r an t e d b y imp l ic a t io n o r o t h e r w i s e un d e r an y pa t e n t o r pa t e n t r i g h t s o f a n a l o g d e v i c e s . t r adem ar ks and r e g i st e r ed tr ad ema r ks ar e the p r o p er t y of the i r r e sp e c t i v e o w ne rs . o n e t e chnology way, p . o. b o x 91 06, nor w ood , ma 020 62- 910 6, u. s . a. t e l: 781. 329. 4 700 w w w . analog .c om fax: 781. 461. 31 13 ? 2005 analog de vices, i n c. al l r i ght s r e ser v ed . fea t ures simple , saf e lin ear char ger f o r single - c e ll lithi u m ba tt er y 4.5 v t o 1 2 v in put v o ltage range a d ju stable char ging cu rr en t u p t o 1.5 a l o w c o st pnp e x t e rnal pass e l ement a u t o ma tic r e v e rse isola tion with no e x t e rnal block i ng diode o u tpu t o v ershoot pr ot ec tion deep dischar g e pr echar g e mode t h ermal sh ut down a u t o ma tic r e char ge p r ogr a mmable t e rmina tion ti mer led char ging sta t u s indic a t o r 4.2 v output v o ltage with 1 % ac cur a c y ov er line an d t e mper a t ur e 1 a shut down sup p ly curr en t small , 8-l ead m s op and 3 3 mm lfcsp pack ages applic a t io ns w i r e less han d s e ts smar t handhelds and pd as digita l ca me r a s single - c ell , lith ium ion-pow e r e d sy stems cra d l e c h a r g e r s gener a l description the ad p2291 is a co n s tan t -c ur r e n t /co n s t an t-vol t a g e lin e a r cha r ger fo r a sin g le-c e l l, li t h i u m io n b a t t er y , r e quir in g j u st a fe w c o mp o n e n t s t o p r o v i d e a s i mp l e a n d s a f e c h a r g i n g s y s t e m t h a t o p era t es f r o m a wi de 4.5 v t o 1 2 v in pu t v o l t a g e ra n g e . i t fe a t ur es a n in t e r n a l ly co n t r o l l e d , m u l t istep cha r g i n g c y cle t h a t im p r o v es b a t t er y life . an ext e r n al , lo w cos t pnp p r o v ide s t h e cha r g i n g c u r r en t t o t h e b a tte r y , and a n e x te r n a l re s i stor s e t s t h e m a x i m u m ch arge c u r r en t. a smal l, ext e r n al ca p a c i t o r p r og ra m s t h e maxi m u m cha r g e t i me . the co n t r o l l er in cl udes a n led dr i v er t o i n dica t e t h e b a t t er y cha r g i n g s t a t us. s a fety fe a t u r es i n cl u d e charg i ng sto p mo de fo r b a tter y f a u l ts, output o v e r s h o o t prote c t i on , a n d t h e r m a l s h ut d o w n . t h e ad p2291 als o f e a t ur es a u t o ma t i c r e v e rs e is ol a t io n, whic h do es n o t r e q u i r e a n ad di ti o n al b l oc kin g d i o d e . th e m u lt i s te p c h arge c y cl e opt i mi z e s t h e b a tte r y ch arg i ng t i me in a s a f e ma nn er . i t f e a t ur es a tr ic kle c h a r g e m o de f o r a deep l y dis c ha rge d c e l l a nd a fa st cha r g i n g m o d e wi t h a max i m u m c u r r en t o f 1.5 a. the ad p2291 co n t r o ls th e end o f c h a r g e wi t h a 4.2 v o u t p u t vol t a g e tha t is 1 % acc u ra t e o v er line an d t e m - pe ra t u r e . i t a u t o m a ti call y r e c h a r g e s th e b a t t e r y i f th e ce ll v o l t a g e dr o p s. w h en t h e in p u t s u p p l y is r e m o v e d , t h e p a r t en t e rs a lo w c u r r en t s t a t e and r e d u ces t h e c u r r en t dra w n f r o m t h e b a t t e r y t o be l o w 1 a . the ad p2291 is a v a i la b l e in both a smal l , 8 - lead mso p pa c k a g e a n d a 3 3 m m l f c s p pa c k a g e tha t i s i d eall y s u i t ed f o r s m a l l , p o r t a b l e ap p l i c at i o n s . ty pic a l oper a t ing circuit adp2291 timer adj rs q1 ctimer input 4 .6v?12v shutdown + in chg bat cin gnd cs drv cout 04873-001 figure 1.
adp2291 rev. a | page 2 of 20 table of contents features .............................................................................................. 1 applications ....................................................................................... 1 general description ......................................................................... 1 typical operating circuit ................................................................ 1 specifications ..................................................................................... 3 absolute maximum ratings ............................................................ 5 esd caution .................................................................................. 5 pin configurations and function descriptions ........................... 6 typical performance characteristics ............................................. 7 theory of operation ...................................................................... 10 precharge mode .......................................................................... 10 end-of-charge mode ................................................................. 10 shutdown mode .......................................................................... 10 charge restart ............................................................................. 10 programmable timer ................................................................. 10 charge status indicator ............................................................. 10 automatic reverse isolation ..................................................... 10 overshoot protection ................................................................. 10 power supply checks ................................................................. 10 thermal shutdown .................................................................... 11 application information ................................................................ 12 setting the maximum charge current .................................... 12 setting the maximum charge time ........................................ 12 external capacitors .................................................................... 12 reverse input protection ........................................................... 12 external pass transistor ............................................................ 13 typical application circuit ....................................................... 14 charge termination ................................................................... 14 selectable charge current ......................................................... 14 thermal protection .................................................................... 14 printed circuit board layout considerations ....................... 16 lfscp layout considerations .................................................. 16 outline dimensions ....................................................................... 17 ordering guide .......................................................................... 17 revision history 11 /05rev. 0 to rev. a changes to equation 7 ................................................................... 13 changes to figure 26...................................................................... 15 changes to table 7.......................................................................... 16 changes to ordering guide .......................................................... 17 updated outline dimensions ....................................................... 17 10/04initial version: revision 0
adp2291 rev. a | page 3 of 20 specifications v in = 5.5 v, v bat = 4.2 v, r adj open, t a = C40c to +85c, typical values are at 25c, unless otherwise noted. 1 table 1. parameter conditions min typ max unit power supply, in input voltage 4.5 12 v current draw fast charge/precharge/end-of-charge modes timeout/shutdown/battery fault 6 1.4 9 1.8 ma ma battery voltage, bat voltage accuracy, end-of-charge (v bat, eoc ) t a = 0c to +50c v in = 4.5 v to 12 v v in C v cs = vrs/10 4.158 4.2 4.242 v load regulation, no battery v in C v cs = 0 to vrs ?80 mv current draw timeout mode, v in = 4.5 v to 12 v 45 a current draw battery fault/shutdown mode, v in = 4.5 v to 12 v 0.1 1 a reverse leakage current power-down mode: v in = float, v bat = 4.2 v 0.1 a fast charge mode sense voltage setpoint (vrs) v in C v cs , r adj = open v in = 4.5 v to 12 v v bat = 3.6 v 140 150 160 mv sense voltage setpoint (vrs) v in C v cs , r adj = 100 k? v in = 4.5 v to 12 v v bat = 3.6 v 40 50 60 mv current regulation adjustment per v of (3 v C v adj ) 67 mv/v precharge mode sense voltage setpoint (vrs) v in C v cs, r adj = open v in = 4.5 v to 12 v v bat = 2 v 10 15 20 mv sense voltage setpoint (vrs) v in C v cs , r adj = 100 k? v in = 4.5 v to 12 v v bat = 2 v 5 10 15 mv bat precharge threshold v bat rising 2.65 2.85 v hysteresis 70 mv shutdown mode adj shutdown threshold v adj falling, v in = 4.5 v 0.30 0.45 v hysteresis 40 mv pull-up current from adj v adj = 0 40 a power-down mode v in power-down threshold v in rising 3.6 4 v hysteresis 220 mv v in _good comparator threshold (v in > v bat ) v in rising 125 170 220 mv hysteresis 110 mv eoc comparator current threshold v in C v cs falling, r adj = open, relative to vrs 7 10 13 % current threshold v in C v cs falling, r adj = 100 k?, relative to vrs 6 10 16 % hysteresis 12 mv restart comparator bat restart threshold v in > 4.5 v, v bat falling, relative to v bat, eoc ?170 mv
adp2291 rev. a | page 4 of 20 parameter conditions min typ max unit battery charge timer charge/discharge timer current 21.0 24.0 27.0 a low threshold 1.2 v high threshold 2.0 v high-low threshold delta 2 750 850 mv overshoot protection bat threshold 4.7 5 5.3 v current sink <2 ms duration 1.5 a chg output output voltage low current = 20 ma 0.45 v output leakage current v chg = 5 v 0.1 1 a base drive capability maximum base drive current 40 ma thermal shutdown shutdown threshold t a rising 135 c hysteresis 35 c 1 all limits at temperature extremes are gua ranteed via correlation using standard stat istical quality control (sqc). typical va lues are at t a = 25c. 2 guaranteed by design; not tested in production.
adp2291 r e v. a | pa ge 5 o f 2 0 absolute maximum ra tings table 2. p a r a me t e r r a ting in, dr v, 1 cs, chg to gnd ?0.3 v to +13.5 v ba t , adj , time r t o gnd ?0.3 v t o ( v in + 0.3 v ) o p era t ing ambi en t t e mpera tur e ?40c to +85c o p era t ing junc tion t e mpera tur e ?40c to +125c ja , 2-la y e r msop -8 220oc/w ja , 4-la y e r msop -8 158oc/w ja , 2-la y e r lfcsp - 8 62oc/w ja , 4-la y e r lfcsp - 8 48oc/w stor age t e mpera tur e range ?65c to +150c l e ad t e mper a tur e s o lder ing (10 sec) 300c 1 pulli n g cu rren t fr o m t h e d r v pi n by d r i v i n g i t below g r ou n d wh i l e vin i s appl ied can cause permanent d amage to the d e vice. s t r e s s es a b o v e t h os e list e d u nde r a b s o l u te m a xim u m r a t i n g s ma y ca us e p e r m a n e n t dama ge to t h e de vi ce. t h is is a st r e ss r a t i ng on ly a n d f u nc t i on a l op e r a t i o n of t h e d e v i c e a t t h e s e or a n y o t h e r con d i t io n s ab o v e t h o s e i ndic a te d i n t h e op er a t io n a l s e c t io n o f t h is sp e c if ic a t io n is no t im pl ie d . e x p o sur e t o a b s o l u te max i m u m r a t i ng co ndi t i on s fo r ex tende d p e r i o d s ma y a f fe c t de vice rel i a b i l i t y . a b s o lute m a x i m u m r a t i ng s a pply i n d i v i du a l ly on ly , no t i n co m b in a t io n . u n less o t h e r w is e sp e c if ie d a l l o t her v o l t a g es re f e re nc e d to g n d . esd caution esd (elec t r o st a t ic dischar g e) se nsitiv e devic e . elec tr os t a tic char ges as high as 4000 v r e adily ac cumula te on the human bod y and t e st eq uipmen t and can dischar g e wi thout det e c t ion. although this pr oduc t f e a tur es pr oprietar y esd pr ot ec tion cir c uitr y , permanen t dama ge may oc cur on dev i c e s sub j ec ted to high ener gy elec tr o s ta tic di scharge s . theref or e , proper esd pr ecautio n s a r e r e c o m m ended to a v oid per f or man c e degrada t ion or l o ss of func tiona l it y .
adp2291 r e v. a | pa ge 6 o f 2 0 pin conf igura t ions and f u ncti on descriptions drv 1 gnd 2 bat 3 cs 4 chg 8 timer 7 in 6 adj 5 adp2291 top view (not to scale) 04873-002 fig u re 2. 8-le ad m s op pin conf ig ur at ion pin 1 indicator 1 drv 2 gnd 3 bat 4 cs 7 timer 8 chg 6i n 5 adj top view (not to scale) adp2291 04873-003 fig u re 3. 8-le ad lf csp pin conf ig ur at ion ta ble 3. pi n f u nct i on d e s c ri pt i o ns p i n no . m n emonic description 1 dr v base dr iv er o u t p ut. c o n t r o ls th e base of an e x ter n al pnp pass transi stor . 2 gnd gr ound . 3 ba t ba tt er y v o ltage sense i n put. 4 cs c u rr en t sense r e sist or nega tiv e i n put. 5 adj char g i ng c u rr en t a d j u st and char ger shut do wn i n put. 6 in p o w e r i n put and c u rr en t sense r e sist or p o sitiv e i n put. 7 timer t imer p r ogr a m ming i n put/disable . 8 chg led char ge sta t us i n dica t o r . this is an open- c ollec t or output.
adp2291 r e v. a | pa ge 7 o f 2 0 1 2 typical perf orm ance cha r acte ristics v in (v) v bat (v ) 4.21 4.205 4.20 4.195 4.19 46 10 8 04873-004 fi gure 4 . ba ttery v o l t a g e vs. input v o lta g e temperature (c) v bat (v ) 4.21 4.205 4.20 4.195 4.19 ? 5 0 ? 25 25 0 125 100 75 50 04873-005 figure 5. batte ry v o ltag e v s . te mpe r a t ure i chg (ma) v bat (v ) 4.22 4.21 4.20 4.19 4.18 0 200 800 600 400 04873-006 figure 6. batte ry v o ltag e v s . ch arge c u rre nt rs = 200 m ? , v ad j = 3 v i bat (v) i chg (ma) 800.0 600.0 700.0 500.0 400.0 300.0 200.0 100.0 0.0 2.50 3.00 4.50 4.00 3.50 04873-007 figure 7. cha r ge c u rre nt v s . battery v o ltag e rs = 200 m ? , v ad j = 3 v temperature (c) i r ever se (na) 250 200 150 100 50 0 ? 5 0 ? 25 0 125 75 100 50 25 04873-008 figure 8. batte ry r e v e rs e cur r ent v s . t e mpe r atur e v in = f l oat , v bat = 4. 2 v temperature (c) v re s t art (v ) 4.10 4.09 4.08 4.07 4.06 4.05 ? 4 0 ? 20 0 100 60 80 40 20 04873-009 figure 9. r e s t art t h res h o l d
adp2291 r e v. a | pa ge 8 o f 2 0 1 2 v in (v) v rs (mv ) 16.0 15.8 15.6 15.4 15.2 15.0 46 10 8 04873-010 fig u re 1 0 . pr ech arg e v rs vs. input v o l t age temperature (c) v rs (mv ) 15.5 15.4 15.3 15.2 15.1 ? 5 0 ? 25 0 2 5 5 0 7 5 100 125 04873-011 fig u re 1 1 . pr ech arg e v rs v s . t e mp er atu r e r adj (k ? ) v rs (mv ) 16 14 12 10 8 100 1k 10k 04873-012 fig u re 1 2 . pr ech arg e v rs vs. r ad j v in (v) v rs (mv ) 153 152 151 150 149 148 46 8 1 0 1 2 04873-013 fi gure 13 . f a st charge v rs vs. inp u t volta g e temperature (c) v rs (mv ) 152 151 150 149 148 ?50 ? 25 0 2 5 5 0 7 5 100 125 04873-014 fi gure 14 . f a st charge v rs v s . t e mper a t ure r adj (k ? ) v rs (mv ) 160 140 120 100 80 60 40 100 1k 10k 04873-015 fi gure 15 . f a st charge v rs vs. r ad j
adp2291 r e v. a | pa ge 9 o f 2 0 1 2 v in (v) bas e driv e (ma) 135 130 125 120 115 46 10 8 04873-016 figure 16. b a se dr ive vs. input volt ag e temperature ( c) bas e driv e (ma) 122 120 118 116 114 112 110 108 106 104 ? 4 0 ? 20 100 40 60 80 20 0 04873-017 figure 17. b a se dr ive vs. temp er ature v in = 5 v ch1 10.0mv ch2 1.00v b w b w m200 s ch2 6.18v 2 1 ch2 = v in 5v offset v in = 5v to 8v ch1 = v bat 4.18v offset 04873-018 fi gur e 18 . l i ne transi ent response i bat = 35 0 ma ch1 20.0mv ch3 10.0mv ? b w m100 s ch3 10.0mv 3 1 ch3 = i bat 200ma/div i bat = 70ma to 700ma ch1 = v bat 4.18v offset 04873-019 fi gur e 19 . l o a d transi ent response v in = 5 v
adp2291 rev. a | page 10 of 20 theory of operation the adp2291 is intended to charge a single-cell, lithium battery from a supply voltage or wall adapter providing 4.5 v to 12 v. the charge controller adjusts the base current of an external pnp transistor to optimize current and voltage applied to the battery during charging. a low value resistor placed in series with the battery charging current provides current measure- ment for the adp2291. to ensure safety and long battery lifetime, the adp2291 charges the battery using a simple step-by-step cycle, as shown in figure 26. the normal charge cycle begins by measuring the battery voltage to determine charge level. if the battery is deeply dis- charged, then low current precharge is initiated. once precharge is complete, normal fast charge at the maximum current (denoted as i max ) begins. this maximum current can be adjusted by varying the sense resistor value or by varying the voltage at the adjust pin. as the battery approaches full capacity, the charging current is reduced until the end-of-charge condition is reached. batteries that are not deeply discharged skip the precharge mode and immediately begin fast charging. each of these modes and associated fault conditions is discussed in detail. precharge mode for deeply discharged cells, the adp2291 charges at a reduced rate when the battery voltage v bat < 2.8 v. this reduced rate is i max /10 when the adj pin voltage is 3 v and i max /5 when the adj pin voltage is 1.5 v. for adj pin voltages in between 3 v and 1.5 v, the charge current can be interpolated. if the battery voltage does not increase past 2.8 v before the precharge timer elapses (typically 30 minutes), a battery fault is assumed and the adp2291 shuts down and does not restart until the input voltage is cycled off and then back on. note that in this mode, shutdown commands are ignored. end-of-charge mode once the voltage loop reduces the charge current to 1/10 of its nominal value, i max (irrespective of the adj voltage), the adp2291 detects the end-of-charge (eoc) state, and the charge status indicator becomes high impedance. low level charging continues until the timer terminates the charge (nominally 30 minutes). shutdown mode when the adj input is pulled below 0.4 v, the adp2291 is put into shutdown mode. when in this mode, the charger is dis- abled; the current drawn from the battery falls to less than 1 a; and the current drawn from in falls to 0.7 ma. when the charger is re-enabled, the charger returns to the start state but quickly sequences through the states until the proper charge mode is reached. charge restart once the charge is complete in the end-of-charge or timeout mode, the adp2291 continually monitors the cell voltage and charge current. when the cell voltage falls by 100 mv or the charge current increases beyond the eoc hysteresis, the adp2291 initiates another charge cycle to keep the cell fully charged. see figure 26. programmable timer the on-chip timer, controlled by an external capacitor ctimer, determines the timeout intervals of the various charger modes. for example, a ctimer value of 0.1 f results in a precharge timeout interval of 30 minutes, a fast charge timeout of 3 hours, and an end-of-charge timeout of 30 minutes. the ratio between precharge and end-of-charge to fast charge timeout is always 1/6. all these time intervals are proportional to the ctimer capacitor value, allowing them to be adjusted over a wide range. connecting the timer pin to ground disables the timer. charge status indicator the adp2291 contains a charge status output, chg , that sinks current when the adp2291 is charging the battery. this output can be used as a visual signal by connecting it to an led, or it can be used to generate a logic-level charge status signal by connecting a resistor between chg and logic high. automatic reverse isolation when the voltage on the bat pin is higher than the voltage on in, the adp2291 automatically connects the base of the pass device to bat. this removes the necessity of having an external diode between the pass device and battery, further reducing the chargers footprint and component count. overshoot protection in the event of a battery disconnect during charging, a voltage overshoot condition on bat could occur. the adp2291 includes an overshoot protection circuit that activates when v bat rises to 5 v and sinks up to 1.5 a to protect the external components. power supply checks to ensure proper operation, the adp2291 checks the absolute voltage level of the input supply and the supply voltage relative to the battery. when the supply in is below 3.8 v, the chip is internally powered down and does not respond to external control. in this power-down mode, the device draws less than 1 a from the battery. the v in good comparator halts operation if the supply voltage is less than 165 mv above the battery voltage, ensuring that charging occurs only if the supply voltage is sufficient.
adp2291 rev. a | page 11 of 20 thermal shutdown i f the ad p2291 j u n c tion t e m p era t ur e r i s e s abo v e 135c, t h er ma l s h u t do w n o c c u rs. e x t r em e j u n c t i o n t e m p era t ur es can b e t h e r e s u l t o f exces s i v e c u r r en t o p er a t io n and/o r hig h am b i e n t t e m p era t ur es. a 35c t e m p era t ur e h y s t er esis is in cl ude d s o tha t t h e ad p2291 do es n o t r e t u r n t o o p era t ion d u r i n g t h er mal sh u t do w n un t i l t h e o n -c hi p t e m p er a t ur e dr o p s b e lo w 100c. control logic timer temp voltage reference gm 3v 1.2v 5v gm gm timer adj bat drv cs in shutdown vin_good restart bat 4.1v bat 2.5v chg 0.4v in bat in 3.8v ipnp c/10 precharge power_down end_of_charge 04873-020 fig u re 2 0 . fun c t i on al bl ock d i ag ra m
adp2291 rev. a | page 12 of 20 appli c a t ion inf o rma t ion setting the maximum charge current the maxi m u m cha r g e c u r r en t is s e t b y cho o sing t h e p r op er c u r r en t s e ns e r e sis t o r , r s , a n d t h e v o l t a g e o n t h e ad j in pu t. the cha r g e r n o minal l y r e gu l a t e s i t s o u t p u t c u r r en t a t t h e p o in t w h er e t h e v o l t ag e acr o s s t h e c u r r en t s e ns e r e sis t o r v in C v cs (def in e d as v rs ) is 150 mv . this s e t p o i n t v o l t a g e ca n be ad j u s t e d b y p u l l in g do w n o n t h e ad j in p u t, w h ich is in ter n a l ly a t t a ch e d thr o ug h a 100 k ? pu l l - u p re s i stor to 3 v . e a ch vo lt of pu l l - d ow n fr o m 3 v r e d u c e s v rs b y 67 m v d u r i ng fast ch a r ge. a min i m u m o f 50 mv is r e ach e d w h en a 100 k ? r e sis t o r is a t tac h e d betw een ad j and g r o u nd . d u r i n g s l o w cha r g e , t h e v o l t a g e acr o s s t h e c u r r en t s e ns e r e sis t o r is 15 mv wi th n o co nn ec tio n t o ad j , and i t dr o p s t o 10 mv wi th a 100 k ? r e sis t o r a t tach e d t o g r o u nd . ther efo r e , t h e maxim u m cha r g e ra t e i max is calc u l a t e d as ) m ( ) mv ( s rs max r v i = (1) w h er e 50 mv v rs 150 mv . a f te r de te r m i n i n g su it abl e v a lu e s for v rs and r s , t h e va l u e o f v ad j and r ad j are c a l c u l a t e d a s v mv mv mv 7 . 66 50 ) ( + = rs adj v v (2) r ad j = 100 k? ? ? ? ? ? ? ? ? ? adj adj v v v 3 ( 3 ) e x am pl e s of re si stor c o mbi n a t i o ns are s h ow n i n t a bl e 4 . table 4. exa m p l es of rs an d r adj selection i ma x rs m? v rs mv v adj v r adj 1.5 a 100 150 3 o p en 1 a 100 100 2.25 300 k 750 ma 100 75 1.87 167 k 500 ma 100 50 1.5 100 k 750 ma 200 150 3 o p en 500 ma 200 100 2.25 300 k 375 ma 200 75 1.87 167 k 250 ma 200 50 1.5 100 k 500 ma 300 150 3 o p en 333 ma 300 100 2.25 300 k 250 ma 300 75 1.87 167 k 167 ma 300 50 1.5 100 k setting the maximum charge time the max i m u m cha r ge t i me is i n te n d e d as a s a fety m e cha n is m t o p r e v en t t h e cha r g e r f r o m t r ickle cha r g i n g t h e ce l l i n def i ni t e l y . i t d o e s not te r m i n a t e ch ar g i ng u n d e r nor m a l ch ar g i ng c o n d i - t i o n s, b u t o n l y w h en t h er e is a fa i l ur e t o r e ach end-o f -cha rg e . a ty p i ca l c e l l ch a r ges a t a 1 c r a te i n ab o u t 1.5 ho urs, dep e ndi ng o n t h e c e l l typ e , t e m p era t ur e , and ma n u fac t ur er . g e n e r a l l y , a t h r e e- h o ur t i m e l i mi t is s u f f i cien t t o p r e v en t a n o r m al cha r g e c y cle f r o m b e ing in ter r u p t e d b y t h e cha r ge t i m e r . i t is r e co m- m e nde d t h a t t h e cel l man u fac t ur er b e co n s u l te d fo r t i min g det a i l s. the max i m u m cha r ge t i me is s e t b y s e le c t in g t h e v a l u e o f t h e ctimer ca p a c i t o r . c a lc u l a t e t h e t i m e r c a p a ci t a n c e using ctimer = t ch g (min u t es) minutes 1800 f 1 (4) the p r e c ha rg e a nd e n d-o f -cha rg e p e r i o d s a r e 1 / 6 t h e d u r a t i on o f th e fas t c h a r g e tim e lim i t . th e c h a r g e ti m e r s a r e co m p le t e l y dis a b l e d b y co nn e c t i n g t h e ti mer p i n to g r o u nd . i f t h e t i m e rs a r e d i s a bl e d , t h e f a u l t and ti me ou t st a t e s a r e ne ver r e ache d , s o th e tim e rs sho u ld o n l y be dis a b l ed if c h a r g i ng is m o ni t o r e d a nd co n t r o l l e d ex ter n a l ly . external c a paci tors u s e an in p u t sup p ly c a p a c i tor ( c i n ) wi t h a v a lu e in t h e 1 f t o 10 f ra n g e a nd p l ace i t c l os e t o the adp2291. this sh o u l d p r o v ide ade q ua te i n p u t b y p a ssing, b u t t h e s e le c t e d ca p a ci t o r sh o u ld b e ch ec k e d in th e ac t u al a p p l ica t ion cir c ui t. c h e c k t h a t t h e i n p u t v o l t a g e do es n o t dr o o p o r o v ersh o o t exces s i v e l y d u r i n g t h e s t a r t- u p t r a n sien t. u s e a b a t t er y o u t p u t ca p a c i t o r (c o u t) w i t h a val u e o f a t le as t 10 f . this ca p a ci t a n c e p r o v i d es co m p en s a t i on w h en n o b a t t e r y lo ad is p r es en t. i n addi t i on, t h e b a t t e r y a n d in t e r c o n n e c t ion s a p p e a r ind u c t i v e a t h i g h f r e q ue n c ies and m u st b e ac co un te d fo r w h en t h e cha r g e r is o p era t e d w i t h a b a t t er y lo a d . th er efo r e , a smal l a m o u n t of o u t p u t ca p a c i t a n c e is n e ces s a r y t o co m p en s a t e fo r t h e in d u c t i v e na t u r e o f t h e b a t t e r y a n d co nn e c t i on s. u s e a mini m u m o u t p u t ca p a c i t a n c e v a l u e o f 1 f fo r a p plic a t io n s w h er e t h e b a t t e r y ca nn o t b e r e m o v e d . reverse input protection t h e d iode d1, shown in figure 22 through figure 25 , is o p t i o n a l . i t is r e q u ir e d o n ly if t h e in pu t a d a p t e r v o l t a g e can be a p p l i e d w i t h a r e v e r s e po la ri ty . i f t h e a d a p te r vo lt ag e i s h i g h e n ou g h , a s c hott ky d i o d e i s re c o m - m e nde d t o minimize t h e v o l t a g e dif f er en ce f r o m t h e ada p t e r to th e c h a r g e r i n p u t a n d th e po w e r d i s s i p a t i o n . ch oo se a d i od e w i th a co n t in uo us c u rr en t ra t i n g hig h en o u g h t o ha n d le b a t t er y cha r g i n g curr en t a t t h e ma xim u m a m b i en t t e m p e r a t ur e . u s e a d i ode wi t h a v o l t a g e ra t i n g g r ea t e r than t h e maxim u m ada p t e r v o l t a g e .
adp2291 rev. a | page 13 of 20 i n cas e s w h er e t h e v o l t a g e dr o p acr o s s t h e p r o t e c t i o n de vice m u s t be k e p t lo w , a p m o s f e t is r e co mm ende d . c o nnec t t h e m o s f e t as sh o w n in f i gur e 21 . adp2291 rs input 4.6v?12v in chg cin cs drv 04873-021 figure 2 1 . r e v e rse i n put pr otect ion external pass transistor c h o o s e t h e e x te r n a l pnp p a ss t r ans i stor b a s e d on t h e g i ve n op e r a t i n g c o nd it i o ns a n d p o we r h a nd l i ng c a p a bi l i t i e s . t h e p a ss de vice is deter m i n e d b y t h e b a s e dr i v e a v a i lab l e, t h e i n p u t and o u t p ut v o l t a g e, a nd t h e max i m u m cha r g e c u r r en t. se l e ct th e pa s s tr a n s i s t o r w i t h a c o ll e c t o r - e m i t t e r b r e a k d o w n v o l t a g e t h a t exc e e d s t h e maxi m u m ada p t e r v o l t a g e . a v ceo ra tin g o f a t leas t 15 v is r e co mm ended . pr o v id in g a charge c u r r en t o f i max wi t h a mi ni m u m b a s e dr i v e o f 40 ma r e q u ires a p n p b e ta of a t leas t min = ma 40 max max i i i = (5) n o t e t h a t th e beta o f a tra n si s t o r d r o p s o f f w i th co llect o r c u r r en t. th er efo r e , mak e s u r e t h e beta a t i max m eet s t h e mini m u m r e q u i r em e n t. f o r cas e s w h er e t h e ada p t e r v o l t a g e is lo w (les s t h a n 5.5 v), calc u l a t e t h e s a t u ra t i o n v o l t a g e b y v ce(sa t ) = v ad apter(m i n ) ? v pro t e c t ? v rs ? v ba t (6) w h er e v pr o t ect is t h e fo r w a r d dro p o f t h e r e v e rs e in pu t prote c t i on . t h e po w e r h a n d l i n g c a pa b i li t y o f th e p n p pa s s tr a n s i s t o r i s a n o t h e r im p o r t a n t p a ram e t e r . t h e maxim u m p o w e r d i s s i p a t io n o f th e pa s s tra n si s t o r i s e s ti ma t e d usi n g p di s s (w) = i ma x (v ad ap t e r(m a x) ? v pr o t e c t ? v rs ? v ba t ) (7) wh e r e v rs = 50 mv t o 150 mv a t v ad j = 1.5 v to 3.0 v , v ba t = 2.8 v , t h e lo w e s t c e l l v o l t a g e w h er e fas t cha r g e ca n o c c u r . n o t e t h a t t h e ada p t e r v o l t a g e can b e ei t h er p r er egu l a t e d o r unr e gu la t e d . i n t h e p r er egu l a t e d cas e , t h e dif f er en ce b e tw e e n t h e max i m u m and mi ni m u m a d a p ter vol t a g e i s sma l l. i n t h is c a s e , u s e t h e ma x i m u m re g u l a te d a d a p te r volt ag e to de te r m i n e t h e max i m u m p o w e r dissi p a t ion. i n t h e unr e gu la te d ca s e , t h e ad a p te r vol t age c a n h a ve a w i de r a nge sp e c i f i e d. h o we ve r , t h e maxim u m v o l t age sp e c if ie d is usua l l y w i t h n o lo ad a p plie d . ther efo r e , t h e w o rs t-cas e p o wer dis s i p a t io n c a lc u l a t io n o f t e n leads t o a n o v er -s p e c i f i ed p a s s de vic e . i n ei t h er cas e , i t is bes t to de te r m i n e t h e l o a d ch ar a c te r i st i c s of t h e a d a p te r to opt i mi z e t h e charger des i g n . f o r exa m ple: v ad apter(m i n) = 5.0 v v ad apter(m a x ) = 6.0 v i ma x = 500 ma v p r o t ect = 0.2 v a t 500 ma v ad j = 3 v v rs = 150 mv min = 5 . 12 ma 40 ma 500 = = i i max v ce(sa t ) = v ad apt e r(m i n ) ? v p r o t ect ? v rs ? v ba t = 5.0 v ? 0.2 v ? 0.15 v ? 4.2 v = 0.45 v p di s s (w ) = i m ax ( v ad apter(m a x) ? v p r o t ect ? v rs ? v ba t ) = 0.50 a (6.0 v ? 0.2 v ? 0.15 v ? 2.8 v) = 1.4 w a g u ide f o r s e l e c t ing t h e pnp p a s s tr a n s i st o r is sho w n in t a b l e 5 . tab l e 5. pnp p a ss tran sistor selection guide v e ndor p a r t number p a ck age ma x pd @ 2 5 c b e ta @ 1 a v c e (sa t ) f a ir c h ild fsb6726 nzt45h8 superso t so t223 0.5 w 1.5 w 150 110 0.5 v 0.1 v on s e mic onduc t or? m t b35200 bcp53t1 mmjt9435 tsop -6 so t223 so t223 0.625 w 1.5 w 1.6 w 200 35 200 0.175 v 0.3 v 0.18 v p h ilips bcp51 so t223 1.3 w 50 0.5 v ze tex z x t10p20de6 z x t2m322 fzt549 f m m t 549 so t23-6 2 mm 2 mm mlp so t223 so t23 1.1 w 1.5 w 2 w 0.5 w 270 270 130 130 0.17 v 0.17 v 0.25 v 0.25 v
adp2291 rev. a | page 14 of 20 ty pical a p plicati o n circuit a ty p i ca l a p plic a t io n c i r c ui t is sh o w n i n f i gur e 22. the cir c ui t i s ca p a b l e o f a 750 ma c h a r g e c u r r en t f o r a n in p u t v o l t a g e o f 4.5 v t o 6 v . h i g h er i n p u t v o l t ages c a n b e u s e d , b u t t h e i n cre a s e d p o wer dissi p a t io n o f t h e p a ss de vi ce m u st b e t a k e n i n to acco un t. adp2291 timer adj rs 200m ? q1 fzt549 d1 bat1000 ctimer 100nf input 4 .6v?12v + in chg bat cin 2.2 f gnd cs drv cout 10 f 04873- 022 fig u re 2 2 . ty p i c a l a pplic at i o n c i r c uit charge te rmination i n s o me a ppl ic a t io ns, t h e cha r ger is re qu ir e d t o t e r m i n a t e cha r g - in g w h e n t h e e o c t h r e sh old is r e ach e d . a u t o ma t i c cha r ger r e st a r t is n o t de sir e d . a d di n g c o m p on en ts r1, c1, a nd q2 t e r m ina t es c h a r g i n g w h en t h e ch g p i n o p en s and pr e v en ts f u r t h e r cha r g i n g un t i l t h e a d a p ter is r e m o ve d and r e ass e r t e d . adp2291 timer adj rs 200m ? q1 fzt549 q2 2n7002 d1 bat1000 ctimer 100nf c1 100nf input 4.6v? 12v + in chg bat cin 2.2 f r1 500k ? gnd cs drv cout 10 f li-ion cell 04873-023 fi gure 23 . sel f -term i na tio n c i rcui t selectable charge current i n a p plic a t io n s w h er e t h e cha r g e c u r r en t n e e d s t o b e s e le c t a b le , u s e t h e c i rc u i t s h ow n i n f i g u re 2 4 . t h i s c i rc u i t a l l o w s a pro c e s - s o r t o det e r m i n e if t h e cha r g e c u r r en t n e e d s t o b e r e d u ce d d u e t o a n i n p u t s o ur ce limi t a t i o n o r a dif f er en t b a t t e r y ca p a ci ty opt i on or s i m p l y to re d u c e t h e st re ss on t h e p a ss t r ans i stor . r 2 a n d q2 all o w t h e c h a r g e curr e n t t o be se l e c t ed bet w een hig h , whic h r e su l t s in a c h a r g e c u r r en t o f 750 ma; and lo w , which r e s u l t s in a c h a r g e c u r r en t o f 250 ma. adp2291 timer adj rs 200m ? r2 100k ? q1 fzt549 q2 2n7002 d1 bat1000 ctimer 100nf input 4.6v? 12v + in chg bat cin 2.2 f gnd cs drv low/high cout 10 f li-ion cell 04873-024 figure 24. s e lectab le ch arg e current circu i t thermal protection i n a p plic a t io n s w h er e t h e o v era l l size m u s t b e s m al l o r t h e in put v o l t a g e ra n g e is wi de , addin g t h er mal r e gu la t i o n is s u g g es t e d . this al lo ws t h e cha r g e r t o m o ni t o r t h e t e m p era t ur e o f t h e p a s s de vice and de cre a s e t h e cha r g e c u r r en t as t h e t e m p era t ur e in cr e a s e s. by ad din g an nt c t h er mist o r t o t h e ad j p i n, i t is p o s s i b le t o accom p lish this; h o w e v e r , ca r e is sti l l r e q u ir e d t o en s u r e t h a t t h e p o w e r dis s i p a t i o n o f t h e p a s s de v i ce is n o t e x ceed ed . adp2291 timer adj rs 200m ? q1 fzt549 r1 470k ntc located near q1 r2 100k d1 bat1000 ctimer 100nf input 4.6v? 12v + in chg bat cin 2.2 f gnd cs drv cout 10 f li-ion cell 04873-025 fi gure 25 . therma l regul a tio n ci rcu i t s o m e s u g g es t e d nt c t h er mis t or s u p p liers a r e li s t e d in t a b l e 6. table 6. n t c thermistor manufacturers v e ndor p a r t number w e bsit e beta therm smd2500k j435j w w w .bet a t her m .c om mur a ta ncp18wm474j w w w .mura t a .c om p a nasonic er t j 0e v474j w w w .panasoni c .c om v i sha y 2322 615 1.474 w w w .vi s ha y . c o m
adp2291 rev. a | page 15 of 20 power-down vrs = 0mv chg = open battery fault vrs = 0mv chg = open end of charge vrs = 15mv chg = open start vrs = 0mv chg = open precharge vrs = 15mv chg = low fast charge vrs = 150mv chg = low time out vrs = 0mv chg = open shutdown vrs = 0mv chg = open vin > 3.8v vbat > 2.8v vbat < 2.8v vbat < 4.1v vadj < 0.4v vadj > 0.4v and temp < 100c vadj < 0.4v vbat < 4.1v or ipnp > c/10 ipnp < c/10 and vbat > 4.1v t = 30 min t = 30 min t = 3 hour temp > 135 c from anywhere asynchronously vin < 3.8v from anywhere a synchronousl y start sequence ends vadj < 0.4v 04873-026 figure 2 6 . st ate d i agra m f o r th e a d p 2 2 91 ctim e r = 0. 1 f
adp2291 rev. a | page 16 of 20 printe d ci rcuit boar d lay o ut consi d era t io ns u s e t h e fol l o w i n g g e n e ra l guide l i n es w h en desig n in g p r in t e d cir c ui t bo a r ds: ? k e ep t h e ou t p u t ca p a ci t o r as clos e t o t h e b a t and gnd pi ns a s p o s s ibl e . ? k e ep t h e in p u t ca p a ci t o r as clos e t o t h e i n an d gnd pin s as p o ssi b le. ? pc boa r d tra c e s w i th la r g e r cr os s- secti o nal a r eas r e m o v e more he at f r om t h e p a s s t r ans i st or . f o r opt i m u m he at t r a n sfer , s p e c if y t h ick cop p er and us e wide t r ace s . ? u s e addi tio n al c o p p er l a yers o r p l a n es t o r e d u c e ther mal r e sis t a n ce. w h en co nn ec tin g t o o t h e r l a yers, us e m u l t i p le vi a s i f pos s i b l e . lf scp layout considerations the lfcs p p a cka g e has an exp o s e d di e p a ddl e o n t h e b o t t o m t h a t ef f i cien t l y co nd uc ts h e a t t o t h e pcb . t o achie v e t h e opt i m u m p e r f or m a nc e f r om t h e l f c s p p a ck ag e , g i ve sp e c i a l co n s idera t io n to t h e la yo u t o f t h e p c b . u s e t h e fol l o w in g l a yo u t guide l i n es fo r t h e lfc s p p a cka g e: ? t h e p a d p a tt e r n i s s h ow n i n f i g u r e 2 7 . fo l l ow t h e p a d di m e n s io n clos el y fo r r e lia b l e s o lder jo in ts, w h i l e ma in t a in in g r e a s o n a b le cle a rances t o p r e v en t s o lder br i d g i n g . ? the t h er mal p a d o f t h e lfcs p p a cka g e p r o v i d es a lo w t h er ma l i m p e dan c e p a t h ( a p p r o x ima t e l y 20c/ w) t o t h e pcb; t h er efo r e , a p r o p erl y desig n e d pcb ef fe c t iv e l y co n- d u c t s t h e h e at a w ay f r o m t h e p a c k a g e . t h i s i s a c h i e v e d by addin g t h er ma l v i as t o t h e p c b t h a t p r o v ide a t h er mal p a t h to t h e i n ne r or b o ttom l a y e r s . n o t e t h a t th e via di a m et e r i s s m all t o p r ev e n t th e so l d e r f r o m f l o w in g t h r o ug h t h e v i a and le a v i n g v o id s in t h e t h er ma l p a d s o l d er jo in t. n o t e als o t h a t t h e t h er mal p a d is a t t a ch e d t o t h e die s u b - s t ra t e ; t h er efo r e , t h e t h er mal pl a n es t o w h ich t h e v i as a t ta c h th e p a c k a g e m u s t b e e l e c tri c a l l y i s o l a t e d o r co nn e c te d to g n d . ? the s o lder mask o p enin g s h o u l d b e abo u t 120 micr o n s (4.7 mi ls) la rger t h a n t h e p a d si ze, r e su l t in g i n a mi ni m u m o f 60 micr o n s (2.4 mi ls) cle a r a n c e b e tw e e n t h e p a d a nd t h e so l d e r m a s k . ? the p a s t e mask o p eni n g is typ i c a l l y desig n e d t o ma t c h t h e pa d s i z e u s ed o n th e pe r i p h e r al pa d s o f th e l f c s p pa c k a g e . this sh o u ld p r o v ide a r e lia b le s o lder jo in t as lon g as t h e s t en cil thic k n ess is a b o u t 0.125 mm. the p a s t e mas k f o r the t h er mal p a d n e eds t o b e de sig n e d f o r t h e maxim u m co v e r a g e to e f fe c t ively re mo v e t h e he a t f r om t h e p a ck age. h o w e ve r , d u e t o t h e p r es e n ce o f t h er mal v i as an d t h e size o f t h e t h er - ma l p a d , e l i m in a t in g v o ids m a y n o t b e p o ssi b l e . ? the r e co m m e nde d p a ste mask ste n ci l t h ick n ess is 0.125 mm. u s e a las e r c u t s t ainl es s s t e e l s t en c i l wi th tra p e z o i d a l w a lls. ? u s e a n o -cle an, t y p e 3 s o lder p a s t e fo r m o u n t i n g t h e lfcs p p a cka g e . a ni t r og en p u rg e d u r i n g t h e r e f l o w p r o c ess is r e co mmende d . ? the p a cka g e ma n u fac t ur er r e co mm e n ds t h a t t h e r e f l o w t e m p era t ur e n o t exceed 220c and t h e time abo v e liq u id us be les s tha n 75 s e co n d s. m a k e sur e th e p r eh ea t ra m p is 3c/s e co nd o r lo w e r . th e ac t u a l t e m p era t ur e p r o f ile dep e n d s on t h e b o a r d s de n s i t y a nd sh o u ld b e d e ter m i n e d by t h e a s s e m b l y h o u s e . 0. 50 2 vias, 0.250 ? 35 m pla ting 3.36 0.90 1.80 2.36 1.90 1.40 0. 30 0. 73 04873-027 fig u re 2 7 . 3 mm 3 mm lfcsp p a d p a t t e rn ( d im ens i ons in mi ll im et ers ) tab l e 7. v a riab les descrip t ion v a riable n a m e d e s c r i p t i o n v x the v o ltage on p i n x. v rs the r e gula tion setpoin t f o r the v o ltage ac r o ss the sense r e si stor ( r s) . v ba t , eo c the ba tter y v o lt age a t the poin t char ging cur r ent is 1/10 the cur r en t setpoin t . i max the char ge cur r en t c o r r e s po nding to vrs, including the eff e c t s of adj pin v o ltag e . c r a te the char ge cur r en t (ma) expr essed as a multiple of the nominal ba t t er y capacit y (mah). a 900 mah capacit y b a tter y , char ged a t a 1/10 c r a te , is equiv a len t to a 90 ma charge cur r en t.
adp2291 rev. a | page 17 of 20 outline dimensions 1 0.50 bsc 0.60 max pin 1 indicato r 1.50 ref 0.50 0.40 0.30 2.75 bsc sq top view 12 max 0.70 max 0. 6 5 t y p seating plane pin 1 indicator 0.90 max 0.85 nom 0.30 0.23 0.18 0.05 max 0.01 nom 0.20 ref 1.89 1.74 1.59 4 1.60 1.45 1.30 3.00 bsc sq 5 8 fig u re 2 8 . 8-le ad l e ad f r a m e chip sc al e p a ck ag e [lfcs p _v d] 3 mm x 3 m m b o dy , v e ry th in, du al l e ad (cp-8- 2) dim e nsio ns sho w n i n mi ll im e t er s compliant to jedec standards mo-187-aa 0.80 0.60 0.40 8 0 4 8 1 5 pin 1 0.65 bsc seating plane 0.38 0.22 1.10 max 3.20 3.00 2.80 coplanarity 0.10 0.23 0.08 3.20 3.00 2.80 5.15 4.90 4.65 0.15 0.00 0.95 0.85 0.75 fig u re 2 9 . 8-le ad m i ni sm al l out lin e pa ck ag e [m s o p] (rm-8) dim e nsio ns sho w n i n mi ll im e t er s ordering guide model t e mper a t ur e r a nge p a ck age descri ption p a ck age o p tion br anding adp2291armz - r7 1 ?40c to +85c 8-l e ad msop rm -8 p08 adp2291a cp z - r7 1 ?40c to +85c 8-l e ad lfcsp_vd cp -8-2 p08 adp2291-e v a l e v alua t i o n boar d 1 z = pb-free part.
adp2291 rev. a | page 18 of 20 notes
adp2291 rev. a | page 19 of 20 notes
adp2291 rev. a | page 20 of 20 notes ? 2005 analo g de v i ces, inc. all rights reserve d . tr adem ar ks and registered tra d emar ks are the prop erty of their respective o w ners . d04873-0-1 1/05(a)

▲Up To Search▲

Price & Availability of ADP2291-15

	To Download ADP2291-15 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .