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AIC1803
Three-Cell Lithium-Ion Battery Protection IC
n FEATURES
l l l l
n DESCRIPTION
The AIC1803 is designed to protect the lithiumion battery from damage or degrading the lifetime due to overcharging, overdischarging and overcurrent for three-cell lithium-ion battery powered systems such as notebook PCs. It can also provide the cell-balancing "bleeding" function to automatically discharge the overcharged cell until the overcharge condition is released. Safe and full utilization charging is ensured by the accurate 30mV overcharge detection. Four 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.
Ultra-Low Quiescent Current at 13A (V CELL=3.5V). Ultra-Low Power-Down Current at 1.3A (V CELL=2.3V) Wide Supply Voltage Range: 2V to 18V. Precision Overcharge Protection Voltage: 4.35V 30mV for the AIC1803A 4.30V 30mV for the AIC1803B 4.25V 30mV for the AIC1803C 4.20V 30mV for the AIC1803D
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l
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Externally Set Overcharge, Overdischarge and Overcurrent Delay Time. Built-in Cell-balancing Bleeding Network under Overcharge Condition. Three Detection Levels for Overcurrent Protection.
n
l
APPLICATIONS
Protection IC for Three-Cell Lithium-Ion Battery Pack.
n
TYPICAL APPLICATION CIRCUIT
R8 1K
1 2
OC CS
VCC VC1
16 15
R4 C4 0.1 F
1K M1 FUSE BATT+ R5 1M BAT1 Q1
M2
C1 R1 2K 0.1 F
3 4
OD NC
UD1 VC2
14 13
R2 2K C2 0.1 F
5 6
CTD 82nF CTI 2.2nF
TD TI
UD2 VC3
12 11
R3 33K C3 0.1F
BAT2 R7 1M BAT3 R6 1M
7
CTC 82nF
TC NC
UD3 GND AIC1803
10 9
8
BATT-
Protection Circuit for Three-Cell Lithium-Ion Battery Pack
DS-1803-01 July 14, 00
www.analog.com.tw
1
AIC1803
n ORDERING INFORMATION
AIC1803 XXX PACKAGE TYPE S: SMALL OUTLINE TEMPERATURE RANGE C=0C~70 C OVERCHARGE PROTECTION VOLTAGE A: 4.35V B: 4.30V C: 4.25V D: 4.20V ORDER NUMBER AIC1803ACS AIC1803BCS AIC1803CCS AIC1803DCS (PLASTIC SO) PIN CONFIGURATION
TOP VIEW
OC CS
1 2
16 VCC 15 VC1 14 UD1 13 VC2 12 UD2 11 VC3 10 UD3 9 GND
OD 3 NC TD TI TC NC 4 5 6 7 8
n ABSOLUTE MAXIMUM RATINGS
Supply Voltage ................................................... ... ... ... ... ... ....................................... 18V DC Voltage Applied on other Pins ............ ... ... ... ... ... ... ..... ....................................... 18V Operating Temperature Range............................... ... ... ... ... ... ......................... -20C~70C Storage Temperature Range ................................ ... ..... ... ... ..................... - 65C ~125C
n TEST CIRCUIT
ROC 1M V OC V CS I OC S1 1 R8 1K 3 VOD 4 14 13 I UD1 I C2 VC2 R2 2K 5 6
CTD 82nF CTI 2.2nF CTC 82nF
OC CS
VCC VC1
16 15
I CC IC 1
R4 1K C4 F 0.1 V C1
2
C1 0.1F
R1 2K
OD NC
UD1 VC2
TD TI
UD2 VC3
12 11
IUD2 IC 3
C2 0.1F
R3 33K 10 9 I UD3 C3 0.1F
VC3
7 8
TC NC
UD3 GND
AIC1803
2
AIC1803
n ELECTRICAL CHARACTERISTICS (Ta=25C, unless otherwise specified.)
PARAMETER TEST CONDITIONS
SYMBOL ICC
MIN.
TYP. MAX. UNIT
13 20 A A A A A A
VCC Pin Input Current in Normal VCELL=3.5V Mode VC1 Pin Input Current in Normal VCELL=3.5V Mode VC2 Pin Input Current in Normal VCELL=3.5V Mode VC3 Pin Input Current in Normal VCELL=3.5V Mode Vcc Pin Input Current in PowerDown Mode VC1,VC2,VC3 Input Current in Power-Down Mode VCELL=2.3V
IC1
0.4
1.0
IC2
0.4
1.0
IC3
0.2
0.5
ICC(PD)
1.3
2
VCELL=2.3V AIC1803A AIC1803B
IC(PD) 4.32 VOCP 4.27 4.22 4.17 VHYS VODP VODR 150 2.27 2.85 135
0.01 4.35 4.30 4.25 4.20 200 2.40 3.00 150
0.15 4.38 4.33 4.28 4.23 250 2.53 3.15 165
V
Overcharge Protection Voltage AIC1803C AIC1803D Overcharge Hysteresis Voltage Overdischarge Protection Voltage Overdischarge Release Voltage Overcurrent Protection Voltage VCELL=3.5V
VCELL1 =VOCP30mVVOCP+30mV
mV V V mV
VOIP
Overcharge Delay Time
VCELL2= VCELL3=3.5 V , CT C=1nF
TOC
10
21
32
mS
VCELL1= 2.5V 2.3V Overdischarge Delay Time VCELL2= VCELL3=3.5V, CTD=1nF VCELL= 3.5V,0.15VOvercurrent Delay Time (1)
TOI1
7
15
23
mS
3
AIC1803
n ELECTRICAL CHARACTERISTICS (Ta=25C, unless otherwise specified.)
PARAMETER
Overcurrent Delay Time (2)
TEST CONDITIONS
VCELL=3.5V, 0.3V1.0V VCELL1=4.4V, VCELL2= VCELL3=3.5V, OC Pin Short to VCC
SYMBOL TOI2
MIN.
2
TYP. MAX. UNIT
4 6 mS
Overcurrent Delay Time (3)
TOI3
150
300
450
S
OC Pin Sink Current
IOC
2.0
2.8
3.6
mA
OD Pin Output "H" Voltage OD Pin Output " Voltage L" Charge Detection Threshold Voltage VCELL=2.3V
VDH VDL VCH
VC C-0.15V
VC C-0.03V
V V V
0.01
0.15
VC C+0.4 VCC+0.55
UD1 Pin Cell-Balancing Bleeding VCELL1=4.4V, Current VCELL2= VCELL3=3.5V UD2 Pin Cell-Balancing Bleeding VCELL2=4.4V, Current VCELL1= VCELL3=3.5V UD3 Pin Cell-Balancing Bleeding VCELL3=4.4V, Current VCELL1= VCELL2=3.5V
IUD1 IUD2 IUD3
5.9
8.4
10.9
mA
6.1
8.7
11.3
mA
6.4
9.2
12.0
mA
Note: VCELL means the battery cell voltage. Therefore,
VCELL1 = VC1 - V C2 VCELL2 = VC2 - V C3 VCELL3 = VC3
n TYPICAL PERFORMANCE CHARACTERISTICS
Vcc Pin Input Current vs. Supply Voltage
Vcc Pin Power-Down Current vs. Supply Voltage Vcc Pin Power-Down Current (A)
1.3
15
Vcc Pin Input Current (A)
Ta=25C
14
Ta=25C
1.2
1.1
13
1.0
12
0.9
11 7.8 8.4 9.0 9.6 10.2 10.8 11.4 12.0
0.8
4.5
4.8
5.1
5.4
5.7
6.0
6.3
6.6
6.9
Supply Voltage (V)
Supply Voltage (V)
4
AIC1803
n TYPICAL PERFORMANCE CHARACTERISTICS (CONTIONED)
Vcc Pin Input Current vs. Temperature VCELL =3.5V
15
Vcc Pin Power-Down Current vs. Temperature
2.0
Vcc Pin Power-Down Current (A)
16
Vcc Pin Input Current (A)
1.8
VCELL=2.3V
14
1.6
13
1.4
12
1.2
11
1.0
10
-20
-10
0
10
Temperature (C)
20
30
40
50
60
70
0.8
-20
-10
0
10
20
30
40
50
60
70
Temperature (C)
Overcharge Protection Voltage vs. Temperature AIC1803C
4.28
Overdischarge Protection Voltage vs. Temperature Overdischarge Protection Voltage (V)
2.42
4.30
Overcharge Protection Voltage (V)
2.41
2.40
4.26
2.39
4.24
2.38
4.22
2.37
4.20
-20
0
20
40
60
70
2.36
Temperature (C)
-20
-10
0
10
Temperature (C)
20
30
40
50
60
70
Overcharge/Overdischarge Delay Time (mS)
Overcurrent Protection Voltage vs. Temperature
152.0
Overcharge/Overdischarge Delay Time vs. Temperature
26
Overcurrent Protection Voltage (V)
151.5
V CELL=3.5V
151.0 150.5 150.0 149.5 149.0 148.5 148.0 -20
24
CTC /CTD=1nF
22
20
18
16
-10
0
10
20
30
40
50
60
70
Temperature(C)
14 -20
-10
0
10
20
30
40
50
60
70
Temperature( C)
5
AIC1803
n TYPICAL PERFORMANCE CHARACTERISTICS (CONTIONED)
Overcurrent Delay Time 1 vs. Temperature
22
Overcharge Release Voltage vs. Temperature
4.08
Overcurrent Delay Time 1 (mS)
20
Overcharge Release Voltage (V)
20 30 40 50 60 70
4.07
VCELL =3.5V
18
4.06
16
4.05
14
4.04
12
4.03
10 -20 -10 0 10
4.02 -20
-10
0
10
20
30
40
50
60
70
Temperature (C)
Temperature ( C)
Overdischarge Release Voltage vs. Temperature
3.01
Overdischarge Release Voltage (V)
3.00
2.99
2.98
2.97 -20
-10
0
10
20
30
40
50
60
70
o Temperature (C)
6
AIC1803
n BLOCK DIAGRAM
CS 2 VC1 15
Battery Voltage Sense Circuit
VCC+0.4V VCC-0.15V
Wake-up Control
VC2 13 11
16
VCC
VC3 UD1
Overcurrent Delay Circuit
VCC-0.3V
14
350 VCC-1V
3
OD
UD2 12
400
Overdischarge Delay Circuit
Power-Down Control
1
OC
UD3
10
450
Overcharge Delay Circuit 1.2V
GND
9
7 TC
56 TD TI
7
AIC1803
n PIN DESCRIPTIONS
PIN 1: OCNMOS open drain output for control of the charge control MOSFET M2. When overcharge occurs, this pin sinks current to switch the external PNP Q1 on, and charging is inhibited by turning off the charge control MOSFET M2. connected to the negative terminal of the battery cell BAT3. PIN10: UD3 This pin is to be connected to the positive terminal of the battery cell BAT3 for cell-balancing bleeding function under overcharge condition.
PIN11: VC3PIN 2: CSInput pin for current sensing. Using the drain-source voltage of the discharge control MOSFET M1 (voltage between VCC and CS), it senses discharge current during normal mode and detects whether charging current is present during power-down mode.
Input pin for battery BAT3 voltage sensing. This pin is to be connected to the positive terminal of the battery cell BAT3. This pin is to be connected to the positive terminal of the battery cell BAT2 for cell-balancing bleeding function under overcharge condition.
PIN12: UD2 -
PIN13: VC2-
PIN 3: OD PIN 4: NC PIN 5: TD PIN 6: TI PIN 7: TC PIN 8: NC PIN 9: GND -
Output pin for control of discharge control MOSFET M1. No connection Overdischarge delay time setting pin. Overcurrent delay pin. time setting PIN14: UD1PIN15: VC1-
Input pin for battery BAT2 voltage sensing. This pin is to be When overdischarge occurs, this pin goes high connected to the positive terminal of the battery cell BAT2.
This pin is to be connected to the positive ter Input pin for battery BAT1 voltage sensing. This pin is to be connected to the positive terminal of the battery cell BAT1. Power supply pin. This pin is to be connected to the positive terminal of the battery cell BAT1.
Overcharge delay time setting pin. No connection. Ground pin. This pin is to be
PIN16: VCC -
n APPLICATION INFORMATIONS
l THE OPERATION
Initialization
On initial power-up , such as connecting the battery pack for the first time to the AIC1803 , the AIC1803 enters the power-down mode . A charger must be applied to the AIC1803 circuit to enable the pack. 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 set by the external capacitor CTC. Inhibition of charging is immediately released when the voltage of the overcharged cell becomes lower than overcharge release voltage (V OCR or VOCP-V HYS) through discharging.
Overcharge Protection
When the voltage of either of the battery cells exceeds the overcharge protection voltage (V OCP)
Overdischarge Protection
When the voltage of either of the battery cells falls below the overdischarge protection voltage (V ODP)
8
AIC1803
beyond the overdischarge delay time (TOD) period, discharging is inhibited by the turning-off of the discharge capacitor control CTD. MOSFET of M1. discharging The is overdischarge delay time is set by the external Inhibition immediately released when the voltage of the overdischarge cell becomes higher than the overdischarge release voltage (V ODR) charging. through (V OCR or VOCP-vHYS ). This function is accomplished by connecting UD1, UD2, UD3 pins to the positive terminals of battery cells BAT1, BAT2, BAT3 respectively. The bleeding current can be decreased by inserting resistors along UD1 pin to BAT1 positive terminal path and UD3 pin to BAT3 positive terminal path.
Power-Down after Overdischarge
When overdischarge occurs, the AIC1803 will go continuously into power-down mode, turning off all the timing generation and detection circuitry to reduce the quiescent current to about 1.3A (V CC =6.9V). In the unusual case where one battery cell is overdischarged while another one under overcharge condition, the AIC1803 will turn off all the detection circuitry except the overcharge detection circuit for the cell under overcharge condition. mode, the AIC1803
Overcurrent Protection
In normal monitors the discharge current by sensing the voltage of CS pin. If the voltage VCC-V CS exceeds the overcurrent protection voltage (V OIP) beyond the overcurrent delay time (TOI) period, overcurrent protection circuit operates the and
discharging is inhibited by the turning-off of the discharge control MOSFET M1. Discharging must be inhibited for at least 256mS after overcurrent takes place to avoid damage to external control MOSFETs due to rapidly switching transient between BATT+ and BATTterminals. The overcurrent condition returns to normal mode when the load is released and the impedance between the BATT+ and BATT- terminals is 20M or higher. The AIC1803 is provided with the three
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 AIC1803 immediately turns on all the timing generation and detection circuitry and goes into normal mode. Charging is determined to be in progress if the CS pin voltage is higher than VCC + 0.4V (charge detection threshold voltage VCH).
overcurrent detection levels (0.15V, 0.3V and 1.0V) and the three overcurrent delay time (TOI1, TOI2 and T ) corresponding to each overcurrent OI3 detection level. TOI1 is set by the external capacitor CTI. TOI2 and TOI3 default to 4mS and 300s respectively, and can not be adjusted due to protection of external MOSFETs
*
DESIGN GUIDE
and
Cell-Balancing Overcharge
Bleeding
after
Setting the Overcharge Overdischarge Delay Time
When either of the battery cells is overcharged, the AIC1803 provides the cell-balancing bleeding function to discharge the overcharged cell at about 9mA until the voltage of the overcharged cell decreases to overcharge release voltage
The overcharge delay time is set by the external capacitor CTC and the overdischarge delay time is set by the external capacitor CTD. The relationship between capacitance of the external capacitors and delay time is tabulated as below.
9
AIC1803
CTC T D(F) C TOC OD(S) T CTC T D(F) C TOC OD(S) T 1n 21m 47n 617m 5n 52m 10n 132m 22n 253m 33n 347m
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). threshold Once the will turn-on change
68n 748m
82n 100n 1004m 1630m
The delay time can also be approximately calculated by the following equations (if CTC , CTD 82nF) : TOC (mS) = 11.8 x CTC(nF) TOD (mS) = 11.8 x CTD(nF)
resistance of the external MOSFET changes, the overcurrent accordingly. current
Setting the Overcurrent Delay Time 1
The overcurrent delay time 1 (TOI1) at 0.15V < VCC-VCS < 0.3V is set by the external capacitor C , TI while the overcurrent delay time 2 and 3 (TOI2 and TOI3) is fixed by IC internal circuit.The relationship between capacitance of the external capacitor and delay time is tabulated as below. CTI(F) 1n 2.2n 3.3n 5n TOI(mS) 4.8 15.0 18.8 23.6 6.8n 31.0 10n 61.8
Suppressing the Ripple Disturbance from Charger
and
To suppress the ripple and disturbance from charger, connecting R1 to R4 and C1 to C4 is recommended.
Controlling MOSFET
switch the
the
Charge
Control
R5, R6, R7 and NPN transistor Q1 are used to charge control MOSFET M2. If overcharge does not occur, no current flows into
Selection MOSFETs
of
External
Control
OC pin and Q1 is turned off, then M2 is turned on. When overcharge occurs, current flows into OC pin and Q1 is turned on, which turns off M2 in turn.
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 =VOIP/IT (IT is ON the overcurrent threshold current). For example, if the overcurrent threshold current IT is designed to be 5A, the turn-on resistance of the external control MOSFETs must be 30m. Users should
Protection at CS Pin
R8 is used for protection of IC when charger is connected in reverse. The charge detection function after overdischarge is possibly disabled by larger value of R8. Resistance of 1K is recommended.
10
AIC1803
n TIMING DIAGRAM
l Overcharge and Overdischarge Protection (VCS=VCC )
VCELL
V BAT2 V ODR V ODP TOD
V BAT3
VOC
Hi-Z
0V
Hi-Z
VOD
V CC 0V
l Overcurrent Protection (VCELL=3.5V)
>256ms VCC VCC- 0.15V VCC - 0.3V <256ms
VCS
VCC - 1V
0V
TOI1 OI1
VOD
VCC 0V 256ms <256ms
VOC
Hi-Z
11
AIC1803
n PHYSICAL DIMENSIONS
l 16 LEAD PLASTIC SO (150 mil) (unit: mm) SYMBOL A A1
E H D
MIN 1.35 0.10 0.33 0.19 9.80 3.80 5.80 0.40
MAX 1.75 0.25 0.51 0.25 10.00 4.00 6.20 1.27
B C D E e
e A
1.27 (TYP)
H L
A1
B
C
L
12

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