AIC1821 one-cell lithium-ion battery protection ic a n alog integrations corporation si-soft research center ds-1821-02 010405 3a1, no.1, li-hsin rd. i , science park , hsinchu 300, taiw an , r.o.c. tel: 886-3-5772500 fax: 886-3 - 5772 510 www.analog.com .tw 1 features red u ctio n i n board size d ue to miniature packag e sot-2 5 a nd le ss external components. ultra-low quiescent current at 7 a (v cc =3. 5 v ) . ultra - lo w po we r- do wn c u rr ent at 0.6 a (v cc =2. 2 v ) . precision overcharge protection voltage 4.35v 50mv for the AIC1821a 4.30v 50mv for the AIC1821b 4.25v 50mv for the AIC1821c 4.20v 50mv for the AIC1821d built-in dela y time circuits for overcha r ge, over-discharge, and overcurrent protection. load detect ion fun c tion during ov ercha r ge mode. two detection levels for overcurrent protection. applications protec tion ic for one-cell lithium-ion battery p a ck. description the aic18 2 1 battery prot ection ic i s desi gne d to protect lithium-i on batt e ry from da mage or deg radi ng the lifetime due to ove r charge, overdi scha rg e, and/or ov ercurre n t for one-cell lithium-io n b a ttery power ed sy st ems, su ch a s cellul a r pho n e s. th e ultra - sm all pa cka ge an d less requi re d external co m pone nts m a ke it ideal to integrate t he aic18 21 i n to the limited spa c e of battery pack. the a c cu rat e 50 mv o v e r c h ar g i ng de te c t io n voltage ensure s safe and full utilization cha r gi ng. fo ur different specifi c ation v a lue s for overcha r ge p r ote c tion voltage are provided fo r variou s p r ote c tion req u ire m ents. t he very low stand by cu rre n t drain s little curre n t from the cell while in storage. typical application circuit ba tt - ba tt + 10 0 k 5 4 3 2 1 r2 r3 fuse c1 0. 1 f r1 10 0 10 m m2 s i 992 6 m1 si99 26 ba tte r y oc cs od gn d vc c ai c 1 8 2 1 protec tion circuit for on e-cell lithium-ion ba tte r y
AIC1821 ordering information example: aic182 1acvtr 4.35v versi on, in sot-2 3 -5 p a cka ge & tapin g & reel pa cki ng type pin co nfigu r atio n sot-23-5 top view vcc od gnd cs oc 3 2 1 4 5 packing type tr: tape & reel bg: bag package type v: sot-23-5 overcha r ge prote c tion a: 4.35v b: 4.30v c: 4.25v d: 4.20v a ic182 1xcxxx sot-23-5 marking part no. marking a i c 1 8 2 1 a c v b l 0 a a i c 1 8 2 1 b c v b l 0 b a i c 1 8 2 1 c c v b l 0 c a i c 1 8 2 1 d c v b l 0 d absolute maximum ratings supply voltage ....................................???????.................................................... 18v dc volta ge applied o n oth e r pins ...............??????????.............................. 18v c h ar ge r vo lta g e ..............?????????.????????................................ 14v ope r ating te mperature ra nge .....................................??????.............. -40 c~85 c storage t e m perature ran g e .........................???????..................... - 65 c~125 c absolute m aximum rating are those value beyond which the life of a device may be impaired. test circuit 100k i cc v oc r3 10m v od v cc v cs r2 5 4 3 2 1 c1 0. 1 f r1 10 0 oc cs od gn d vc c ai c 1 8 2 1 2
AIC1821 electrical characteristics (ta=25 c, unless otherw i se specified.) parameter test conditions symbol m i n . t y p . m a x . u n i t supply current v cc =3. 5 v i cc 7 1 1 a power-down current v cc = 2 .2v, i pd 0 . 6 1 . 0 a a i c 1 8 2 1 a 4 . 3 0 4 . 3 5 4.40 a i c 1 8 2 1 b 4 . 2 5 4 . 3 0 4.35 a i c 1 8 2 1 c 4 . 2 0 4 . 2 5 4.30 overcharge protection voltage AIC1821d v ocp 4.15 4 . 2 0 4 . 2 5 v overcharge hysteresis voltage v hy s 2 3 0 3 0 0 3 7 0 m v overdischarge protection voltage v odp 2.25 2 . 4 2 . 5 5 v overdischarge release voltage v odr 2.85 3 . 0 3 . 1 5 v overcurrent protection voltage v cc =3. 5 v v oip 1 8 0 2 0 0 2 2 0 m v overcharge delay time v cc =v ocp -0.1 v ocp + 0.1v t oc 1 0 0 1 5 0 2 0 0 m s overdischarge delay time v cc = 2.6v 2.2v t od 6 1 2 1 8 m s ov ercurrent delay time (1) v cc =3. 5 v , 1v>v cs >0. 2 v t oi1 6 1 2 1 8 m s ov ercurrent delay time (2) v cc = 3 .5v, v cs >1v t oi2 5 0 s od pin output ?h? voltage v dh v cc -0.2 v cc - 0 . 0 2 v od pin output ?l? voltage v dl 0 . 0 1 0 . 1 v load dectection threshold voltage v cc =v ocp ? 50mv v ld 0 . 3 0 . 4 v charge detection threshold voltage v cc =2. 4 v v ch - 0 . 4 5 - 0 . 3 v note1: specifications are production tested at ta = 25 c. specifications over the -40 c to 85 c operating temperature range are assured by design, characte rization and correlation with statistical quality controls (sqc). 3
AIC1821 typical performance characteristics 2 . 83 . 0 3 . 23 . 4 3 . 6 3 . 8 4 . 04 . 2 6.4 6.8 7.2 7.6 8.0 ta = 2 5 c s u pply c u rr e n t v s . s u pply v o lta g e su pp l y vo l t a g e ( v ) supply c u rre nt ( a) - 4 0 - 2 0 0 2 04 0 6 08 5 6 7 8 9 10 0 v cc= 3 . 5v s u pply c u rr e n t v s . t e mp er a t ur e su pp l y c u r r e n t ( a ) t e mp er at ur e ( c) -4 0 - 2 0 0 2 0 4 0 6 0 8 0 0. 54 0. 57 0. 60 0. 63 0. 66 vc c=2. 2v p o w e r-d o w n c u rre n t v s . t e m p e r a t u r e po wer - down cu r r en t ( a ) t e m p er at u r e ( c) -4 0 - 2 0 0 2 0 4 0 6 0 8 0 4. 2 4 4. 2 6 4. 2 8 4. 3 0 4. 3 2 4. 3 4 4. 3 6 a ic182 1b o v er ch ar g e p r ot e c t i o n v o lta g e v s . t e mp e r at ur e o v er cha r ge p r ote c tio n v o ltag e (v ) t e mp er at u r e ( c) t e m perat u r e ( c) - 4 0 - 2 0 0 2 04 0 6 08 2. 3 8 2. 3 9 2. 4 0 2. 4 1 2. 4 2 0 o v e r d i s c ha r ge prot ec t i on v o l t age v s . t e mperat u r e o v e r di sch a r ge p r ote c ti o n v o lt ag e (v ) t em pe ra t u re ( c) - 4 0 - 2 0 0 2 04 0 6 08 198 199 200 201 202 0 vc c=3 . 5 v o v e rcur ren t p rote ct i on v o l ta ge v s . t em p e ra tu r e o v er cur r en t p r o t e c tio n v o l t ag e (mv ) 4
AIC1821 typical performance characteristics (continued) -4 0 - 2 0 0 2 0 4 0 6 0 8 0 3.90 3.95 4.00 4.05 4.10 o v er c h a r g e r e l e a s e v o l t a g e v s . t e m p er at ur e o ve rc h ar g e r e l ea s e v o lt age (v ) t em p e r a t ur e ( c) ai c 182 1b t empe rat u re ( c) -4 0 - 20 0 2 0 4 0 6 0 8 0 2. 9 0 2. 9 5 3. 0 0 3. 0 5 3. 1 0 o v e rd is c h arg e r e l e as e v o l t ag e v s . t e m p eratu r e o v er disc h a rg e r e le a s e v o lt age (v ) -40 - 20 0 2 0 4 0 6 0 8 0 12 5 13 0 13 5 14 0 14 5 ov erch arge de la y t i me v s . t e m p erat u r e ov erc h arg e de l a y t i me ( m s) t e mp er a t ur e ( c) t e mp era t ure ( c) -4 0 - 20 0 2 0 4 0 6 0 8 0 8 9 10 11 12 ov e r d i sc h a rg e d e l a y t i me v s . t e mp er atu r e o v er disch a r ge d e lay t i me ( m s ) t e m p er at u r e ( c) - 4 0 - 2 0 0 2 04 06 0 8 8 9 10 11 12 0 vcc = 3. 5 v o v er c u r r en t d e l a y t i m e 1 v s . t e m p er at u r e o v e r cu r r en t delay t i m e 1( m s ) 5
AIC1821 ? block diagram p o w e r- dow n con t r o l wak e - u p co n t r o l -0. 3 v 3 4 1 2 5 vc c o v er di s c h a r g e de l a y c i r c u i t ov e r c h ar ge de l a y c i r c u i t o v er cu rr en t del a y c i r c u i t en a b l e en a b l e l oad d e t e ct ed 0. 3v 0. 2v cs gnd oc od 1. 2v 1v ? pin descriptions pin 1: oc - pmos ope n drai n out put for cont rol of the cha r g e control mosfet m 2 . in no rmal mode, this pmos t u rns on to pull the gate of the mosfet m2 to high, then the m o sfet m2 tu rn s on. whe n ove r charge o c curs, thi s pmos turns off, then no current flows th ro u gh r3 a n d the mosfet m2 turns off. pin 2: gnd - gro und pi n. this pi n is to b e con n e c ted to the negative terminal of the battery cell. pin 3: od - output pin for co ntrol of the discha rg e co ntrol mosf et m1. whe n ove r di scha rge occurs, this pin goe s low to turn off the mosfet m1 and discha rging is inhibited. pin 4: cs - input pin f o r current sen s in g. usi ng the sum of drain - source voltages of the mosfet m1 and the mosf et m2 (voltage betwe en cs and g n d), it sen s e s discha rg e cu rre nt durin g norm a l mode a nd d e t ects wheth e r cha r ge cu rre nt is p r ese n t du ring power- down mod e . it also u s ed to detect wheth e r loa d is conne cte d during overcharge mode. pin 5: vcc - powe r sup p ly pin. this pin is to be con n e c ted to the positive terminal of the battery cell. 6
AIC1821 one-cell lithium-ion battery protection ic 7 ? application information z the operation overcharge protection when the voltage of the battery cell exceeds the overcharge protection voltage (v ocp ) beyond the overcharge delay time (t oc ) period, charging is inhibited by the turning-off of the charge control mosfet m2. the overcharge delay time is fixed to 100ms by ic internal circuit. the overcharge condition is released in two cases: 1. the voltage of the battery cell becomes lower than the overcharge release voltage (v ocr or v ocp - v hys ) through self-discharge. 2. the voltage of the battery cell falls below the overcharge protection voltage (v ocp ) and a load is connected. when the battery voltage is above v ocp , the overcharge condition is never released even a load is connected to the pack. overdischarge protection when the voltage of the battery cell goes below the overdischarge protection voltage (v odp ) beyond the overdischarge delay time (t od ) period, discharging is inhibited by the turning-off of the discharge control mosfet m1. the overdischarge delay time defaults to 10ms. inhibition of discharging is immediately released when the voltage of the battery cell becomes higher than overdischarge release voltage (v odr ) through charging. overcurrent protection in normal mode, the AIC1821 continuously monitors the discharge current by sensing the voltage of cs pin. if the voltage of cs pin exceeds the overcurrent protection voltage (v oip ) beyond the overcurrent delay time (t oi ) period, the overcurren t protection circuit operates and discharging is inhibited by the turning-off of the discharge control mosfet m1. the overcurrent condition returns to the normal mode when the load is released and the impedance between the batt+ and batt- terminals is 1m : or higher. the AIC1821 is provided with the two overcurrent detection levels (0.2v and 1v) and the two overcurrent delay time (t oi1 and t oi2 ) corresponding to each overcurrent detection level. load detection after overcharge the load detection function after overcharge is implemented by detecting the cs pin voltage. once a load is connected to the battery pack after overcharge, di scharge current flows through the parasitic diode of mosfet m2 and there is a diode voltage drop between cs and gnd. load is determined to be connected to the pack if the cs pin voltage is above load detection threshold voltage (v ld ). power-down after overdischarge when overdischarge occu rs, the AIC1821 will go into power-down mode, turning off all the timing generation and detection circuitry to reduce the quiescent current to 0.6 p a (v cc =2.2v). at the same time, the cs pin is pull-high to vcc through a high resistance resistor. charge detection after overdischarge when overdischarge occurs, the discharge control mosfet m1 turns off and discharging is inhibited. however, charging is still permitted
AIC1821 8 through the parasitic diode of m1. once the charger is connected to the battery pack, the AIC1821 immediately turns on all the timing generation and detection circuitry. charging is determined to be in progress if the voltage between cs and gnd is below charge detection threshold voltage (v ch ). z design guide selection of external control mosfets because the overcurrent protection voltage is preset, the threshold current for overcurrent detection is determined by the turn-on resistance of the discharge control mosfet m1. the turn-on resistance of the external control mosfets can be determined by the equation: r on =v oip / (2 x i t ) (i t is the overcurrent threshold curr ent). for example, if the overcurrent threshold current i t is designed to be 3a, the turn-on resistance of the external control mosfets must be 33m : . users should be aware that turn-on resistance of the mosfet changes with temperature variation due to heat dissipation. it changes with the voltage between gate and source as well. (turn- on resistance of a mosfet increases as the voltage between gate and source decreases). once the turn-on resistance of the external mosfet changes, the overcurrent threshold current will change accordingly. suppressing the ripple and disturbance from charger to suppress the ripple and disturbance from charger, connecting r1, c1 to vcc pin is recommended. protection at cs pin r2 is used for latch-up protection when charger is connected under overdischarge condition and overstress protection at reverse connecting of a charger. larger value of r2 reduces the charger leakage current in overcharge mode, but possibly disables the charge detection function after overdischarge. resistance of 100k : is recommended.
AIC1821 ? timing diagram z overcharge and overdischarge protection ch a r ge r c o n n e ct e d lo a d c o n n e c t e d lo a d c o n n e c t e d ch a r ge r c o n n e c t e d cha r g e r c o nn e c t e d hi - z t od t oc t oc v cc v oc v od 0v v cc v cc v od r v od p v oc p v oc p -v hy s hi - z z overcurrent protection (v cc =3.5v) v cc v cc 0. 2v v od v ba tt- 0v 0v 1v v cc AIC1821 c a a2 b wit h pl a t i n g 0. 25 a1 s e c t i o n a-a b a se m etal e1 d e aa e1 s ee v i e w b e 0 0.9 0 0.3 0 1. 50 2. 60 2. 80 0.0 8 0.3 0 0.0 5 e l1 l e1 c e e1 d b a2 a1 0. 95 bsc 8 0. 60 1. 90 bsc 0. 60 ref 1.3 0 1.7 0 3. 00 3. 00 0. 22 0. 50 0. 15 0.9 5 min . s y m b o l a1 . ma x. sot - 2 5 mi ll im et er s 10 physical dimensions sot-23-5 (unit: mm) 4 5 note: information provided b y aic is b e lieved to be accurate and relia ble. ho w e ver, we cannot assume responsibility f o r use of an y circuitry othe r th an circuitry en tir e ly em bodied in an aic product; nor for an y infrin gement of patent s or other rights of thir d parties that may result from its use. we reserve the right to change the circuitry and specif ications w i thout notice. life support policy : ai c does not authorize an y ai c product fo r us e in life support devices and/or sy st ems. life support device s or sy stems are devi c es or sy stems w h ich, (i) a r e int ended for surgic al implant into th e bod y or (ii) su pport or sustain life, and w hose failure to perform , w h e n prope rl y used in accordance w i th inst ructions for use provided in t he labeling, can be reasonabl y exp e cted to result in a significant injury to the user. vi ew b l1 l s e at i n g p l ane ga ug e pl a n e
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