SS6821 Single-Cell Lithium-Ion Battery Protection IC FEATURES DESCRIPTION The SS6821 battery protection IC is designed to protect a lithium-ion battery from damage or reduced lifetime due to over-charge, over-discharge, and/or over-current in single-cell lithium-ion battery powered systems, such as cellular phones. The ultra-small package and few external components make the SS6821 ideal for integration into the limited space of of a battery pack. Reduction in board size with miniature SOT-23-5 package and few external components. Ultra-low quiescent current of 7µA (VCC=3.5V). Ultra-low power-down current of 0.6 µ A (VCC=2.2V). Precision over-charge protection voltage 4.35V ± 50mV for the SS6821A 4.30V ± 50mV for the SS6821B 4.25V ± 50mV for the SS6821C 4.20V ± 50mV for the SS6821D Built-in delay-time circuits for over-charge, overdischarge, and over-current protection. Load detection function during overcharge mode. Two detection levels for over-current protection. The accurate ±50mV over-charging detection voltage ensures safe and full-utilization charging. Four different specification values for over-charge protection voltage are provided for various protection requirements. The very low standby current drains little current from the cell while in storage. APPLICATIONS Protection IC for single-cell Lithium-Ion battery packs. TYPICAL APPLICATION CIRCUIT FUSE BATT+ BATTERY R1 M1 SSM9926 100 5 VCC 4 CS C1 0.1µF 2 3 GND R2 OD OC 100K 1 R3 SS6821 10M BATTM2 SSM9926 Protection Circuit for Single-Cell Lithium-Ion Battery 12/6/2004 Rev.2.02 www.SiliconStandard.com 1 of 10 SS6821 ORDERING INFORMATION PIN CONFIGURATION SS6821-XCXXX Packing: TR: Tape and reel SOT-23-5 TOP VIEW Package type V: SOT-23-5 VCC CS 5 4 1 OC 2 3 GND OD Overcharge protection: A: 4.35V B: 4.30V C: 4.25V D: 4.20V Example: SS6821-A CVTR à 4.35V version, in SOT-23-5 package shipped in tape and reel ABSOLUTE MAXIMUM RATINGS Supply Voltage ....................................………………….................................................... 18V DC Voltage Applied on other Pins ...............………………………….............................. 18V Charger Voltage ..............……………………….……………………................................ 14V Operating Temperature Range .....................................……………….............. -40°C~85°C Storage Temperature Range .........................…………………..................... - 65°C~125°C TEST CIRCUIT ICC R1 5 VCC 100 VCC CS C1 R2 4 VCS 100K 0.1µF 2 VOD 3 GND OD OC 1 SS6821 12/6/2004 Rev.2.02 www.SiliconStandard.com VOC R3 10M 2 of 10 SS6821 ELECTRICAL CHARACTERISTICS PARAMETER (Ta=25°C, unless otherwise specified.) TEST CONDITIONS SYMBOL MIN. TYP. MAX. UNIT Supply Current VCC=3.5V ICC 7 11 µA Power-Down Current V CC=2.2V, I PD 0.6 1.0 µA Over-charge Protection Voltage SS6821A 4.30 4.35 4.40 4.25 4.30 4.35 SS6821C 4.20 4.25 4.30 SS6821D 4.15 4.20 4.25 SS6821B VOCP V Over-charge Hysteresis Voltage VHYS 230 300 370 mV Over-discharge Protection Voltage VODP 2.25 2.4 2.55 V Over-discharge Release Voltage VODR 2.85 3.0 3.15 V 180 200 220 mV 100 150 200 ms Over-current Protection Voltage VCC=3.5V VOIP Over-charge Delay Time VCC=VOCP-0.1→ TOC VOCP + 0.1V Over-discharge Delay Time VCC= 2.6V → 2.2V TOD 6 12 18 ms Over-current Delay Time (1) VCC=3.5V, 1V>VCS>0.2V TOI1 6 12 18 ms Over-current Delay Time (2) VCC=3.5V, VCS>1V TOI2 50 µs OD Pin Output “H” Voltage VDH OD Pin Output “L” Voltage VDL 0.01 0.1 V 0.3 0.4 V Load Detection Threshold Voltage VCC=VOCP – 50mV VLD Charge Detection Threshold Voltage VCC=2.4V VCH 12/6/2004 Rev.2.02 www.SiliconStandard.com VCC-0.2 VCC-0.02 -0.45 -0.3 V V 3 of 10 SS6821 TYPICAL PERFORMANCE CHARACTERISTICS Supply Current vs. Supply Voltage Supply Current vs. Temperature 10 8.0 Vcc=3.5V Ta=25°C 7.6 Supply Current (µA) Supply Current (µA) 9 7.2 6.8 8 7 6 6.4 2.8 3.0 3.2 3.4 3.6 3.8 4.0 5 -40 4.2 -20 0 Overcharge Protection Voltage (V) Power-Down Current (µA) 0.63 0.60 0.57 -20 0 20 40 60 SS6821B 4.32 4.30 4.28 4.26 4.24 -40 80 -20 0 20 40 60 80 Temperature (°C) Overdischarge Protection Voltage vs. Temperature Overcurrent Protection Voltage vs. Temperature 202 2.42 Overcurrent Protection Voltage (mV) Overdischarge Protection Voltage (V) 80 4.34 Temperature (°C) 2.41 2.40 2.39 -20 0 20 40 60 80 Vcc=3.5V 201 200 199 198 -40 -20 Temperature (°C) 12/6/2004 Rev.2.02 60 4.36 Vcc=2.2V 2.38 -40 40 Overcharge Protection Voltage vs. Temperature Power-Down Current vs. Temperature 0.66 0.54 -40 20 Temperature (°C) Supply Voltage (V) www.SiliconStandard.com 0 20 40 Temperature ( °C) 60 80 4 of 10 SS6821 TYPICAL PERFORMANCE CHARACTERISTICS (Continued) Overdischarge Release Voltage vs. Temperature Overcharge Release Voltage vs. Temperature 3.10 Overdischarge Release Voltage (V) Overcharge Release Voltage (V) 4.10 SS6821B 4.05 4.00 3.95 3.90-40 -20 0 20 40 60 3.05 3.00 2.95 2.90 -40 80 Temperature ( °C) 20 40 60 80 Overdischarge Delay Time vs. Temperature Overcharge Delay Time vs. Temperature 12 Overdischarge Delay Time (mS) Overcharge Delay Time (mS) 0 Temperature ( °C) 145 140 135 130 125 -40 -20 -20 0 20 40 60 80 11 10 9 8 -40 -20 Temperature (°C) 0 20 40 60 80 Temperature (°C) Overcurrent Delay Time 1 vs. Temperature Overcurrent Delay Time 1(mS) 12 Vcc=3.5V 11 10 9 8 -40 -20 0 20 40 60 80 Temperature (°C) 12/6/2004 Rev.2.02 www.SiliconStandard.com 5 of 10 SS6821 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 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 high, and the MOSFET M2 turns on. When over-charge occurs, this PMOS turns off, no current flows through R3 and the MOSFET M2 turns off. MOSFET M1 and discharging is halted. PIN 4: CS PIN 2: GND - Ground pin. This pin is to be connected to the negative terminal of the battery cell. PIN 3: OD 12/6/2004 Rev.2.02 - Output pin for control of discharge control MOSFET When over-discharge occurs, pin goes low to turn off the M1. this the - Input pin for current sensing. Using the sum of the drain-source voltages of the MOSFET M1 and the MOSFET M2 (voltage between CS and GND), it senses the discharge current during normal mode and detects whether charging current is present during the powerdown mode. It is also used to detect whether the load is connected during over-charge mode. PIN 5: VCC - Power supply pin. This pin is to be connected to the positive terminal of the battery cell. www.SiliconStandard.com 6 of 10 SS6821 APPLICATION INFORMATION turning off of the discharge control MOSFET M1. OPERATION The over-current condition returns to the normal mode when the load is released and the Over-charge Protection When the voltage of the battery cell exceeds the overcharge protection voltage (VOCP) for longer than the overcharge delay time (TOC) period, charging is halted by turning off the charge control MOSFET M2. The overcharge delay time is fixed to 100ms by circuitry internal to the IC. The over-charge condition is impedance between the BATT+ and BATTterminals is 1MΩ or higher. The SS6821 is provided with two overcurrent detection levels (0.2V and 1V) and two over-current delay times (TOI1 and TOI2) corresponding to each over-current detection level. released in one of two ways: Load detection after overcharge 1. The voltage of the battery cell becomes The load detection function after over-charge is lower than the over-charge release voltage implemented by detecting the CS pin voltage. (VOCR or VOCP- VHYS) through self-discharge. Once a load is connected to the battery pack The voltage of the battery cell falls below after an over-charge, discharge current flows the over-charge protection voltage (VOCP) through the parasitic diode of MOSFET M2 and because a load has been connected. there is a diode voltage drop between CS and When the battery voltage is above VOCP, the GND. A load is determined to be connected to over-charge condition is never released even if the pack if the CS pin voltage is above the load a load is connected to the pack. detection threshold voltage (VLD). Over-discharge protection Power-down after over-discharge 2. When the voltage of the battery cell goes When an over-discharge occurs, the SS6821 below the over-discharge protection voltage will go into power-down mode, turning off all the (VODP) for longer than the over-discharge delay timing generation and detection circuitry to time (TOD) period, discharging is halted by reduce turning off the discharge control MOSFET M1. (VCC=2.2V). At the same time, the CS pin is The over-discharge delay time defaults to pulled high to VCC through a high resistance 10ms. Discharging is immediately resumed resistor. the quiescent current to 0.6µA when the voltage of the battery cell becomes higher than over-discharge release voltage Charge detection after over-discharge (VODR) through charging. When over-discharge occurs, the discharge control MOSFET M1 turns off and discharging is Over-current protection halted. However, charging is still permitted In normal mode, the SS6821 continuously through the parasitic diode of M1. Once the monitors the discharge current by sensing the charger is connected to the battery pack, the voltage of the CS pin. If the voltage of the CS SS6821 immediately turns on all the timing pin exceeds the over-current protection voltage generation and detection circuitry. Charging is (VOIP) for longer than the over-current delay determined to be in progress if the voltage time (TOI) period, the over-current protection between CS and GND is below the charge circuit operates and discharging is halted by detection threshold voltage (VCH . ). 12/6/2004 Rev.2.02 www.SiliconStandard.com 7 of 10 SS6821 Once the on-resistance of the external MOSFET DESIGN GUIDE changes, the over-current threshold current will Selection of external control MOSFETs change accordingly. Because the over-current protection voltage is pre-set, the threshold current for over-current Suppressing the ripple and disturbance from the charger detection is determined by the on-resistance of To suppress the ripple and disturbance from the the discharge control MOSFET M1. The charger, connecting R1, C1 to the VCC pin is required on-resistance of the external control recommended. MOSFETs can be determined by the equation: RON=VOIP/ (2 x IT) (IT is the over-current threshold current). For example, if the overcurrent threshold current IT is designed to be 3A, the on-resistance of the external control MOSFETs must be 33mΩ. Users should be aware that on-resistance of the MOSFET changes with temperature variation due to heat dissipation. It changes with the voltage between gate and source as well. (Onresistance of a MOSFET increases as the Protection at CS pin R2 is used for latch-up protection when the charger is connected under an over-discharge condition, and over-stress protection for accidental reverse-connection of the charger. A larger value of R2 reduces the charger leakage current in over-charge mode, but may possibly disable the charge detection function after overdischarge. A resistance value of 100KΩ is recommended. voltage between gate and source decreases). 12/6/2004 Rev.2.02 www.SiliconStandard.com 8 of 10 SS6821 TIMING DIAGRAMS l Over-charge and over-discharge 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 Over-current protection (VCC=3.5V) VCC 1V VBATT0.2V 0V TOI1 <TOI1 VOD TOI2 VCC 0V VOC 12/6/2004 Rev.2.02 VCC www.SiliconStandard.com 9 of 10 SS6821 PHYSICAL DIMENSIONS SOT-23-5 (unit: mm) C D L H E θ1 e A A2 SYMBOL 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 1.90 (TYP) H 2.60 3.00 L 0.37 — θ1 1° 9° SOT-23-5 MARKING Part No. SS6821ACV SS6821BCV SS6821CCV SS6821DCV Marking BL0A BL0B BL0C BL0D Information furnished by Silicon Standard Corporation is believed to be accurate and reliable. However, Silicon Standard Corporation makes no guarantee or warranty, express or implied, as to the reliability, accuracy, timeliness or completeness of such information and assumes no responsibility for its use, or for infringement of any patent or other intellectual property rights of third parties that may result from its use. Silicon Standard reserves the right to make changes as it deems necessary to any products described herein for any reason, including without limitation enhancement in reliability, functionality or design. No license is granted, whether expressly or by implication, in relation to the use of any products described herein or to the use of any information provided herein, under any patent or other intellectual property rights of Silicon Standard Corporation or any third parties. 12/6/2004 Rev.2.02 www.SiliconStandard.com 10 of 10