AIC1821 PRELIMINARY ONE-CELL LITHIUM-ION BATTERY PROTECTION IC SPEC NO: DS-1821-P1 06/07/00 n FEATURES n DESCRIPTION l Reduction in Board Size due to Miniature Package SOT-25 and Less External Components. l Ultra-Low Quiescent Current at 7µA (V CC =3.5V). l Ultra-Low Power-Down Current at 0.4µA (V CC =2.3V). l Precision Overcharge Protection Voltage The AIC1821 battery protection IC is designed to protect lithium-ion battery from damage or degrading the lifetime due to overcharge, overdischarge, and/or overcurrent for one-cell lithium-ion battery powered systems, such as cellular phones. The ultra-small package and less required external components make it ideal to integrate the AIC1821 into the limited space of battery pack. 4.35V ± 30mV for the AIC1821A 4.30V ± 30mV for the AIC1821B 4.25V ± 30mV for the AIC1821C l l l 4.20V ± 30mV for the AIC1821D Built-in Delay Time Circuits for Overcharge, Overdischarge, and Overcurrent Protection. Load Detection Function during Overcharge Mode. Two Detection Levels for Overcurrent Protection. The accurate ±30mV overcharging detection voltage ensures safe and full utilization charging. Three different specification values for overcharge protection voltage are provided for various protection requirements. The very low standby current drains little current from the cell while in storage. n APPLICATIONS l Protection IC for One-Cell Lithium-Ion Battery Pack. n TYPICAL APPLICATION CIRCUIT FUSE BATT+ BATTERY R1 100 5 C1 0.1µF 2 3 M1 SI9926 VCC CS 4 GND R2 OD OC 100K 1 R3 AIC1821 10M BATTM2 SI9926 Protection Circuit for One-Cell Lithium-Ion Battery ANALOG INTEGRATIONS CORPORATION www.analog.com.tw 4F, 9 Industry E. 9th Road, Science-based IndustrialPark , Hsinchu, Taiwan, R.O.C. TEL: (8863)577-2500 FAX:(8863)577-2510 1 AIC1821 ONE-CELL LITHIUM-ION BATTERY PROTECTION IC SPEC NO: DS-1821-P1 06/07/00 n ORDERING INFORMATION AIC1821 XCX ORDER NUMBER PACKAGE TYPE V: SOT-23-5 TOP VIEW AIC1821ACV AIC1821BCV AIC1821CCV AIC1821DCV (SOT-23-5) OVERCHARGE PROTECTION A: 4.35V B: 4.30V C: 4.25V D: 4.20V PIN CONFIGURATION VCC CS 5 4 1 OC 2 3 GND OD n ABSOLUTE MAXIMUM RATINGS Supply Voltage .................................... … … … … … ..................................................... 18V DC Voltage Applied on other Pins ............... … … … … … … … … … … .............................. 18V Operating Temperature Range Storage Temperature Range ..................................... … … … … … … . ............. -40°C~85°C ......................... … … … … … … … ..................... - 65°C~125°C n TEST CIRCUIT ICC R1 5 V CC 100 CS C1 0.1µF R2 4 VCS 51K 2 VOD VCC 3 GND OD OC AIC1821 1 VOC R3 10M S1 ANALOG INTEGRATIONS CORPORATION www.analog.com.tw 4F, 9 Industry E. 9th Road, Science-based IndustrialPark , Hsinchu, Taiwan, R.O.C. TEL: (8863)577-2500 IOC FAX:(8863)577-2510 2 AIC1821 ONE-CELL LITHIUM-ION BATTERY PROTECTION IC SPEC NO: DS-1821-P1 06/07/00 n ELECTRICAL CHARACTERISTICS (Ta=25° C, unless otherwise specified.) PARAMETER TEST CONDITIONS SYMBOL MIN. TYP. MAX. UNIT Supply Current VCC =3.5V ICC 7 11 µA Power-Down Current VCC =2.3V, I PD 0.4 1.0 µA Overcharge Protection Voltage AIC1821A 4.32 4.35 4.38 4.27 4.30 4.33 AIC1821C 4.22 4.25 4.28 AIC1821D 4.17 4.20 4.23 AIC1821B V VOCP Overcharge Hysteresis Voltage VHYS 230 300 370 mV Overdischarge Protection Voltage VODP 2.45 2.6 2.75 V Overdischarge Release Voltage VODR 2.85 3.0 3.15 V 180 200 220 mV 250 500 750 mS Overcurrent Protection Voltage VCC =3.5V VOIP Overcharge Delay Time VCC =VOCP-0.1→ TOC VOCP + 0.1V Overdischarge Delay Time VCC = 2.5V →2.3V TOD 5 10 15 mS Overcurrent Delay Time (1) VCC =3.5V, 1V>VCS>0.2V TOI1 5 10 15 mS Overcurrent Delay Time (2) VCC =3.5V, VCS>1V TOI2 50 µS OC Pin Source Current VCC =3.5V, OC pin short to GND IOC 240 440 µA OD Pin Output “H” Voltage VDH VCC-0.1 OD Pin Output “L” Voltage VDL 0.01 0.1 V 0.3 0.4 V Load Dectection Threshold Voltage VCC =VOCP –50mV VLD Charge Detection Threshold Voltage VCC =2.3V VCH -0.45 ANALOG INTEGRATIONS CORPORATION www.analog.com.tw 4F, 9 Industry E. 9th Road, Science-based IndustrialPark , Hsinchu, Taiwan, R.O.C. TEL: (8863)577-2500 340 VCC-0.02 V -0.3 FAX:(8863)577-2510 V 3 AIC1821 ONE-CELL LITHIUM-ION BATTERY PROTECTION IC SPEC NO: DS-1821-P1 06/07/00 n BLOCK DIAGRAM Wake-up Control Enable -0.3V Load Detected CS 0.3V 4 0.2V Enable Overcurrent Delay Circuit 3 VCC 5 OD 1V Overdischarge Delay Circuit Power-down Control Overcharge Delay Circuit 1.2V GND 2 1 OC n PIN DESCRIPTIONS PIN 1: OC - PMOS open drain output for control of the charge control MOSFET M2. In normal mode, this PMOS turns on to pull the gate of the MOSFET M2 to high, then the MOSFET M2 turns on. When overcharge occurs, this PMOS turns off, then no current flows through R3 and the MOSFET M2 turns off. PIN 2: GND - Ground pin. This pin is to be connected to the negative terminal of the battery cell. PIN 3: OD - Output pin for control of the discharge control MOSFET M1. When overdischarge occurs, this pin goes low to turn off the MOSFET M1 and discharging is inhibited. PIN 4: CS - Input pin for current sensing. Using the sum of drain-source voltages of the MOSFET M1 and the MOSFET M2 (voltage between CS and GND), it senses discharge current during normal mode and detects whether charge current is present during power-down mode. It also used to detect whether load is connected during overcharge mode. PIN 5: VCC - Power supply pin. This pin is to be connected to the positive terminal of the battery cell. ANALOG INTEGRATIONS CORPORATION www.analog.com.tw 4F, 9 Industry E. 9th Road, Science-based IndustrialPark , Hsinchu, Taiwan, R.O.C. TEL: (8863)577-2500 FAX:(8863)577-2510 4 AIC1821 ONE-CELL LITHIUM-ION BATTERY PROTECTION IC SPEC NO: DS-1821-P1 06/07/00 n APPLICATION INFORMATIONS l THE OPERATION 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 ). Overcharge Protection When the voltage of the battery cell exceeds the overcharge protection voltage (V OCP) beyond the overcharge delay time (TOC ) 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 VOCP- VHYS) 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 VOCP, the overcharge condition is never released even a load is connected to the pack. Power-Down after Overdischarge When overdischarge occurs, the AIC1821 will go into power-down mode, turning off all the timing generation and detection circuitry to reduce the quiescent current to 0.4µA (V CC =2.3V). 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 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 ). Overdischarge Protection When the voltage of the battery cell goes below the overdischarge protection voltage (V ODP) beyond the overdischarge delay time (TOD ) period, discharging is inhibited by the turning-off of the discharge control MOSFET M1. The overdischarge delay time defaults to 100mS. 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 (TOI) period, the overcurrent 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 20MΩ or higher. The AIC1821 is provided with the two overcurrent detection levels (0.2V and 1V) and the two overcurrent delay time (TOI1 and TOI2) 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, discharge current flows through the parasitic diode of MOSFET M2 and there is a diode l 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: RON =VOIP/ (2 x IT) (IT is the overcurrent threshold current). For example, if the overcurrent threshold current TI is designed to be 3A, the turn-on resistance of the external control MOSFETs must be 33mΩ. 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 ANALOG INTEGRATIONS CORPORATION www.analog.com.tw 4F, 9 Industry E. 9th Road, Science-based IndustrialPark , Hsinchu, Taiwan, R.O.C. TEL: (8863)577-2500 FAX:(8863)577-2510 5 AIC1821 ONE-CELL LITHIUM-ION BATTERY PROTECTION IC SPEC NO: DS-1821-P1 06/07/00 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. recommended. Resistance of 100KΩ is n TIMING DIAGRAM l Overcharge and Overdischarge Protection TO C TO C VCC VOCP VOCP -VHYS VODR VODP TO D VOC VCC VOD VCC Hi-Z Hi-Z 0V charger connected l load connected charger connected load connected charger connected Overcurrent Protection (VCC=3.5V) VCC 1V VBATT0.2V 0V TOI1 <TOI1 VOD TOI2 VCC 0V VOC VCC ANALOG INTEGRATIONS CORPORATION www.analog.com.tw 4F, 9 Industry E. 9th Road, Science-based IndustrialPark , Hsinchu, Taiwan, R.O.C. TEL: (8863)577-2500 FAX:(8863)577-2510 6 AIC1821 ONE-CELL LITHIUM-ION BATTERY PROTECTION IC SPEC NO: DS-1821-P1 06/07/00 n PHYSICAL DIMENSIONS l SOT-23-5 (unit: mm) C D L H E θ1 e MIN MAX A 1.00 1.30 A1 — 0.10 A2 0.70 0.90 b 0.35 0.50 C 0.10 0.25 D 2.70 3.10 E 1.40 1.80 A A2 e A1 b l SYMBOL 1.90 (TYP) H 2.60 3.00 L 0.37 — θ1 1° 9° SOT-23-5 MARKING Part No. AIC1821ACV AIC1821BCV AIC1821CCV AIC1821DCV Marking BL0A BL0B BL0C BL0D ANALOG INTEGRATIONS CORPORATION www.analog.com.tw 4F, 9 Industry E. 9th Road, Science-based IndustrialPark , Hsinchu, Taiwan, R.O.C. TEL: (8863)577-2500 FAX:(8863)577-2510 7