AIC1811 One-Cell Lithium-Ion Battery Protection IC n FEATURES l n DESCRIPTION Reduction in Board Size due to Miniature Package SOT-23-5 and Less The AIC1811 battery protection IC is designed to External protect lithium-ion battery from damage or Components. degrading l Ultra-Low Quiescent Current at 7µA (V CC =3.5V). overdischarge, and/or overcurrent for one-cell l Ultra-Low Power-Down Current at 0.4µA (V CC lithium-ion battery powered systems, such as =2.3V). cellular phones. The ultra-small package and less Precision Overcharge Protection Voltage required external components make it ideal to l l l l the lifetime due to overcharge, 4.35V ± 50mV for the AIC1811A integrate the AIC1811 into the limited space of 4.30V ± 50mV for the AIC1811B battery pack. 4.25V ± 50mV for the AIC1811C The accurate ±50mV overcharging detection Built-in Delay Time Circuits for Overcharge, voltage ensures safe and full utilization charging. Over-discharge, and Overcurrent Protection. Three different specification values for overcharge Load Detection Function during Overcharge protection Mode. protection requirements. The very low standby Two Detection Levels for Overcurrent Protection. current drains little current from the cell while in voltage are provided for various storage. n APPLICATIONS l Protection IC for One-Cell Lithium-Ion Battery Pack. n TYPICAL APPLICATION CIRCUIT BATT+ FUSE BATTERY R1 M1 SI9926 100 5 VCC CS C1 0.1µF 2 3 4 GND R2 OD OC 51K 1 R3 AIC1811 10M BATTM2 SI9926 Protection Circuit for One-Cell Lithium-Ion Battery DS-1811-00 June 7, 00 www.analog.com.tw 1 AIC1811 n ORDERING INFORMATION AIC1811 XCX ORDER NUMBER PACKAGE TYPE V: SOT-23-5 OVERCHARGE PROTECTION A: 4.35V B: 4.30V C: 4.25V PIN CONFIGURATION TOP VIEW AIC1811ACV AIC1811BCV AIC1811CCV (SOT-23-5) VCC CS 5 1 OC 4 2 3 GND OD n ABSOLUTE MAXIMUM RATINGS Supply Voltage ....................................… … … … … ..................................................... 18V DC Voltage Applied on other Pins ...............… … … … … … … … … … .............................. Operating Temperature Range Storage Temperature 18V .....................................… … … … … … .............. -40°C~85°C Range .........................… … … … … … … ..................... - 65°C~125°C n TEST CIRCUIT ICC R1 5 V CC 100 CS C1 0.1µF R2 4 VCS 51K 2 VO D VCC 3 GND OD OC AIC1811 1 VO C R3 10M S1 IOC 2 AIC1811 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 AIC1811A 4.30 4.35 4.40 4.25 4.30 4.35 4.20 4.25 4.30 AIC1811B VOCP AIC1811C V Overcharge Hysteresis Voltage VHYS 150 200 250 mV Overdischarge Protection Voltage VODP 2.2 2.4 2.6 V Overdischarge Release Voltage VODR 2.6 2.9 3.2 V 180 200 220 mV 50 100 150 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 50 100 150 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 150 300 450 µS OC Pin Source Current VCC =3.5V, OC pin short to GND IOC 240 340 440 µA OD Pin Output “H” Voltage VDH OD Pin Output “L” Voltage VCC-0.1 VCC0.02 V 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 -0.3 V 3 AIC1811 n BLOCK DIAGRAM Wake-up Control Enable -0.3V Load Detected CS 0.3V 4 Enable Overcurrent Delay Circuit 0.2V 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 discharge control MOSFET When overdischarge occurs, pin goes low to turn off the M1. this 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 powerdown 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. 4 AIC1811 n APPLICATION INFORMATIONS THE OPERATION overcurrent protection circuit operates and discharging is inhibited by the turning-off of the Overcharge Protection discharge control MOSFET M1. The overcurrent When the voltage of the battery cell exceeds the condition returns to the normal mode when the overcharge protection voltage (V OCP) beyond the load is released and the impedance between the overcharge delay time (TOC ) period, charging is BATT+ and BATT- terminals is 20MΩ or higher. inhibited by the turning-off of the charge control The AIC1811 is provided with the two overcurrent MOSFET M2. The overcharge delay time is fixed detection levels (0.2V and 1V) and the two to 100mS by IC internal circuit. The overcharge overcurrent condition is released in two cases: corresponding to each overcurrent detection level. delay time (TOI1 and TOI2) 1. The voltage of the battery cell becomes lower than the overcharge release voltage (V OCR or Load Detection after Overcharge VOCP- VHYS) through self-discharge. 2. The voltage of the battery cell falls below the The load detection function after overcharge is overcharge protection voltage (V OCP) and a implemented by detecting the CS pin voltage. load is connected. Once a load is connected to the battery pack after When the battery voltage is above VOCP, the overcharge, discharge current flows through the overcharge condition is never released even a parasitic diode of MOSFET M2 and there is a load is connected to the pack. 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 Overdischarge Protection voltage (V LD ). When the voltage of the battery cell goes below the overdischarge protection voltage (V ODP) beyond the overdischarge delay time (TOD ) period, Power-Down after Overdischarge discharging is inhibited by the turning-off of the When overdischarge occurs, the AIC1811 will go discharge The into power-down mode, turning off all the timing overdischarge delay time defaults to 100mS. generation and detection circuitry to reduce the Inhibition of discharging is immediately released quiescent current to 0.4µA (V CC =2.3V). At the when the voltage of the battery cell becomes same time, the CS pin is pull-high to VCC through higher than overdischarge release voltage (V ODR) a high resistance resistor. control MOSFET M1. through charging. Charge Detection after Overdischarge Overcurrent Protection In normal mode, the AIC1811 When overdischarge occurs, the discharge control continuously MOSFET M1 turns off and discharging is inhibited. monitors the discharge current by sensing the However, charging is still permitted through the voltage of CS pin. If the voltage of CS pin exceeds parasitic diode of M1. Once the charger is the overcurrent protection voltage (V OIP) beyond connected to the battery pack, the AIC1811 the overcurrent delay time (TOI) period, the immediately turns on all the timing generation and 5 AIC1811 detection circuitry. Charging is determined to be in between gate and source decreases). Once the progress if the voltage between CS and GND is turn-on below charge detection threshold voltage (V CH ). changes, the overcurrent threshold current will resistance of the external MOSFET change accordingly. DESIGN GUIDE Suppressing the Ripple and Disturbance from Charger Selection of External Control MOSFETs To suppress the ripple and disturbance from Because the overcurrent protection voltage is charger, connecting R1, C1 to VCC pin is preset, the threshold current for recommended. 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 Protection at CS pin be determined by the equation: RON =VOIP/ (2 x IT) R2 is used for latch-up protection when charger is (IT is the overcurrent threshold current). For connected under overdischarge condition and example, if the overcurrent threshold current IT is overstress protection at reverse connecting of a designed to be 3A, the turn-on resistance of the charger. Larger value of R2 reduces the charger external control MOSFETs must be 33mΩ. Users leakage current in overcharge mode, but possibly should be aware that turn-on resistance of the disables MOSFET changes with temperature variation due overdischarge. to heat dissipation. It changes with the voltage recommended. the charge detection Resistance of function 51KΩ after is between gate and source as well. (Turn-on resistance of a MOSFET increases as the voltage 6 AIC1811 n TIMING DIAGRAM l Overcharge and Overdischarge Protection TOC TOC VCC VOCP VOCP-VHYS VODR VODP TOD 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 T OI1 <TOI1 VOD T OI2 VCC 0V VOC VCC 7 AIC1811 n PHYSICAL DIMENSIONS l SOT-25 (unit: mm) C D L H E θ1 e A A2 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 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. AIC1811ACV AIC1811BCV AIC1811CCV Marking EA0A EA0B EA0C 8