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PRELIMINARY
AIC1821
ONE-CELL LITHIUM-ION BATTERY PROTECTION IC
SPEC NO: DS-1821-P1 06/07/00
n FEATURES
l
n DESCRIPTION
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. 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.
Reduction in Board Size due to Miniature Package SOT-25 and Less External Components. Ultra-Low Quiescent Current at 7A (V CC =3.5V). Ultra-Low Power-Down Current at 0.4A (V CC =2.3V). Precision Overcharge Protection Voltage 4.35V 30mV for the AIC1821A 4.30V 30mV for the AIC1821B 4.25V 30mV for the AIC1821C 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.
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n APPLICATIONS
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Protection IC for One-Cell Lithium-Ion Battery Pack.
n TYPICAL APPLICATION CIRCUIT
FUSE BATT+
R1 BATTERY 100 C1 0.1F
5
VCC
CS
4
2 3
GND OD AIC1821 OC 1 R3 10M
R2 100K
M1 SI9926
BATTM2 SI9926
Protection Circuit for One-Cell Lithium-Ion Battery
ANALOG INTEGRATIONS CORPORATION
4F, 9 Industry E. 9th Road, Science-based IndustrialPark , Hsinchu, Taiwan, R.O.C.
www.analog.com.tw
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 PACKAGE TYPE V: SOT-23-5 OVERCHARGE PROTECTION A: 4.35V B: 4.30V C: 4.25V D: 4.20V ORDER NUMBER AIC1821ACV AIC1821BCV AIC1821CCV AIC1821DCV (SOT-23-5) PIN CONFIGURATION
TOP VIEW VCC 5 CS 4
1 OC
2 GND
3 OD
n ABSOLUTE MAXIMUM RATINGS
Supply Voltage .................................... ... ... ... ... ... ..................................................... 18V ..................................... ... ... ... ... ... ... . ............. -40C~85C ......................... ... ... ... ... ... ... ... ..................... - 65C~125C DC Voltage Applied on other Pins ............... ... ... ... ... ... ... ... ... ... ... .............................. 18V Operating Temperature Range Storage Temperature Range
n TEST CIRCUIT
ICC R1 V CC 100 C1 0.1F 2 VOD 3 GND OD OC 1 R3 10M VOC S1 5 VCC CS 4 R2 VCS 51K
AIC1821
IOC
ANALOG INTEGRATIONS CORPORATION
4F, 9 Industry E. 9th Road, Science-based IndustrialPark , Hsinchu, Taiwan, R.O.C.
www.analog.com.tw
TEL: (8863)577-2500 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
Supply Current Power-Down Current Overcharge Protection Voltage
TEST CONDITIONS
VCC =3.5V VCC =2.3V, AIC1821A AIC1821B
SYMBOL ICC I PD
MIN.
TYP.
7 0.4
MAX.
11 1.0 4.38 4.33 4.28 4.23 370 2.75 3.15 220
UNIT
A A
4.32 4.27 VOCP 4.22 4.17 VHYS VODP 230 2.45 2.85 180
4.35 4.30 4.25 4.20 300 2.6 3.0 200
V
AIC1821C AIC1821D Overcharge Hysteresis Voltage Overdischarge Protection Voltage Overdischarge Release Voltage Overcurrent Protection Voltage Overcharge Delay Time VCC =3.5V VCC =VOCP-0.1 VOCP + 0.1V Overdischarge Delay Time Overcurrent Delay Time (1) Overcurrent Delay Time (2) OC Pin Source Current VCC = 2.5V 2.3V VCC =3.5V, 1V>VCS>0.2V VCC =3.5V, VCS>1V VCC =3.5V, OC pin short to GND TOD TOI1 TOI2 IOC VDH VDL VCC =VOCP -50mV VLD
mV V V mV
VODR VOIP TOC
250
500
750
mS
5 5
10 10
15 15 50
mS mS S A V
240 VCC-0.1
340 VCC-0.02 0.01 0.3
440
OD Pin Output "H" Voltage OD Pin Output "L" Voltage Load Dectection Threshold Voltage Charge Detection Threshold Voltage
0.1 0.4
V V
VCC =2.3V
VCH
-0.45
-0.3
V
ANALOG INTEGRATIONS CORPORATION
4F, 9 Industry E. 9th Road, Science-based IndustrialPark , Hsinchu, Taiwan, R.O.C.
www.analog.com.tw
TEL: (8863)577-2500 FAX:(8863)577-2510
3
AIC1821
ONE-CELL LITHIUM-ION BATTERY PROTECTION IC
SPEC NO: DS-1821-P1 06/07/00
n BLOCK DIAGRAM
Wake-up Control -0.3V Enable Load Detected
CS
4
0.2V
0.3V
Enable
Overcurrent Delay Circuit
3 VCC 5
1V
OD
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. 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 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
PIN 5: VCC - Power supply pin. This pin is to be connected to the positive terminal of the battery cell.
ANALOG INTEGRATIONS CORPORATION
4F, 9 Industry E. 9th Road, Science-based IndustrialPark , Hsinchu, Taiwan, R.O.C.
www.analog.com.tw
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
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. 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 occurs, the AIC1821 will go into power-down mode, turning off all the timing generation and detection circuitry to reduce the quiescent current to 0.4A (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.
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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 T is designed to I 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.
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 20M 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.
Suppressing the Ripple and Disturbance from Charger
To suppress the ripple and disturbance from charger, connecting R1, C1 to VCC pin is recommended.
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 ANALOG INTEGRATIONS CORPORATION
4F, 9 Industry E. 9th Road, Science-based IndustrialPark , Hsinchu, Taiwan, R.O.C.
Protection at CS pin
R2 is used for latch-up protection when charger is www.analog.com.tw
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
100K
is
n TIMING DIAGRAM
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Overcharge and Overdischarge Protection
TO C TO C
VCC
VOCP VOCP -VHYS VODR VODP
TO D
VOC
VCC
Hi-Z
Hi-Z
VOD
VCC
0V
charger connected
load connected
charger connected
load connected
charger connected
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Overcurrent Protection (VCC=3.5V)
VCC
1V
VBATT0.2V 0V TOI1 VOD
VCC 0V
VOC
VCC
ANALOG INTEGRATIONS CORPORATION
4F, 9 Industry E. 9th Road, Science-based IndustrialPark , Hsinchu, Taiwan, R.O.C.
www.analog.com.tw
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)
D C L HE
SYMBOL A A1 A2 b C
MIN 1.00 -- 0.70 0.35 0.10 2.70 1.40
MAX 1.30 0.10 0.90 0.50 0.25 3.10 1.80
e
1
D E e
A2
A
1.90 (TYP) 2.60 0.37 1 3.00 -- 9
A1 b
H L 1
l
SOT-23-5 MARKING
Part No. AIC1821ACV AIC1821BCV AIC1821CCV AIC1821DCV Marking BL0A BL0B BL0C BL0D
ANALOG INTEGRATIONS CORPORATION
4F, 9 Industry E. 9th Road, Science-based IndustrialPark , Hsinchu, Taiwan, R.O.C.
www.analog.com.tw
TEL: (8863)577-2500 FAX:(8863)577-2510
7

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