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MITSUMI
Detection of Lithium Ion Battery Overcharging MM1373
Detection of Lithium Ion Battery Overcharging
Monolithic IC MM1373
Outline
This IC detects overcharging of lithium ion batteries. It is designed for use with three or four battery cells, and
detects battery voltages for each cell. An overcharge detection delay time can be set using an external
capacitor. The overcharge detection signal output is open-collector, and goes low when overcharging is
detected.
Features
1. Consumption current VCEL=3.8V 3.0µA typ.
2. Consumption current V
CEL=2.3V 0.3µA typ.
3. Input current between cell pins V
CEL=3.8V ±0.3µA max.
4. Overcharge detection voltage A type 4.35V±50mV
5. Overcharge detection delay time C
T=0.22µF 1.5S typ.
6. Detection voltage can be changed to accommodate customer needs
Package
SOP-8C
SOP-8E
Applications
1. For secondary protection of lithium ion battery packs
Overcharge Detection ICs
MM1373 Detection voltage Hysteresis
Rank A 4.350V 250mV
Rank B 4.250V 250mV
Rank C 4.225V None
Rank D 4.130V None
Rank E 4.450V 100mV
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MITSUMI
Detection of Lithium Ion Battery Overcharging MM1373
Pin Assignment
1432
8567
SOP-8C, SOP-8E
1 OUT
2 C
T
3 GND
4 V1
5 V2
6 V3
7 V4
8 V
CC
Block Diagram
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MITSUMI
Detection of Lithium Ion Battery Overcharging MM1373
Pin Description
Pin no. Pin name Function Internal equivalent circuit diagram
1 OUT Reset output pin
2 CT Delay capacitance pin
4 V1 Cell 1 power supply
5 V2 Cell 2 power supply
6 V3 Cell 3 power supply
7 V4 Cell 4 power supply
8 VCC
3 GND
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MITSUMI
Detection of Lithium Ion Battery Overcharging MM1373
Absolute Maximun Ratings
Recommended Operating Conditions
Electrical Characteristics
(Except where noted otherwise, Ta=25°C, V
CEL
=V4-V3=V3-V2=V2-V1=V1-GND, VCC=4 V
CEL
)
*
1 VCC
>
=
V4
>
=
V3
>
=
V2
>
=
V1
>
=
-
0.3
*
2: A current no greater than 100µA should be passed through pin Ct.
Item Symbol Ratings Units
V
CC input voltage VCC
V4 input voltage *1 V4
V3 input voltage
*
1 V3
-
0.3~24 V
V2 input voltage
*
1 V2
V1 input voltage
*
1 V1
C
T pin voltage
*
2 VCT
-
0.3~24 V
V
OUT pin voltage VOUT
-
0.3~24 V
Allowable loss Pd 300 mW
Operating temperature T
OPR
-
20~+80 °C
Storage temperature T
STG
-
40~+125 °C
Item Symbol Ratings Units
Input voltage between cells 1 Vop1 2.0~4.35 V
V
CC input voltage Vop2 4.0~18 V
Item Symbol Measurement conditions Min. Typ. Max. Units
Consumption current 1 I1 V
CEL=3.8V 3.0 6.0 µA
Consumption current 2 I2 V
CEL=2.3V 0.3 0.5 µA
Pin I/O current between cells I3 V
CEL=3.8V (V4, V3, V2, V1 side) ±0.0 ±0.3 µA
Overcharge detection voltage V
S VCEL=L H, Ta=
-
20~+70°C 4.30 4.35 4.40 V
Hysteresis voltage HSY V
CEL=L H L 0.20 0.25 0.30 V
Overcharge detection delay time T
PLH CT=0.22µF 1.0 1.5 2.0 S
Output voltage L V
OL IL=100µA 0.4 V
Output leakage current I
LEAK VCEL=3.8V, VOUT=24V 0.1 µA
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MITSUMI
Detection of Lithium Ion Battery Overcharging MM1373
Timing Chart
4.35V
V1~V4
C
T
OUT
OUT
(When C
T is shorted)
(When C
T is open)
4.10V
1.80V
0.60V
1.5S
Application Circuits
Note : When pin Ct is shorted or left open, the output goes low when overcharging is detected.
Characteristics
1
0
1
2
3
4
5
6
23
4.10 4.35
Input voltage (No delay) (V)
Output voltage (V)
0.0
-
25 25 75
0.5
1.0
1.5
2.0
2.5
3.0
Temperature (°C)
-
1100ppm
-
2200ppm
Delay time (S)
Detection voltage Output delay time
Note : By shorting each cell, two-, three- and four-cell series can be accommodated. A V4 cell should always
be connected. If the V4 cell is shorted, the chip may not function correctly.
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