MITSUMI
Protection of Lithium-Ion Batteries MM1412
Protection of Lithium-Ion Batteries
Monolithic IC MM1412
Outline
This IC is used to protect lithium-ion batteries consisting of two cells. It adopts a compact package and has
the functions of previous models, with functions for overcharge detection, overdischarge detection and
overcurrent detection. A dead time can be set externally.
Features
1. Overcharge detection voltage accuracy (0°C to 50°C)
2. Consumption current (Vcell=4.5V)
3. Consumption current (Vcell=3.5V)
4. Consumption current (Vcell=1.9V)
5. Overcharge sensing dead time
±25mV/cell
150µA typ.
15.0µA typ.
0.5µA typ.
can be set externally.
Package
VSOP-8A
Applications
IC for protection of lithium-ion batteries consisting of two cells.
Pin Assignment
1
2
8
7
6
5
3
4
1
2
3
4
5
6
VSOP-8A
7
8
OC
GD
CS
GND
TD
VL
V
CC
VH
MITSUMI
Protection of Lithium-Ion Batteries MM1412
Block Diagram
MITSUMI
Protection of Lithium-Ion Batteries MM1412
Pin Description
Pin No. Pin name
Overcharge detection output pin
1
OC
PNPT
R
open collector output
Overcharge mode: ON
Normal mode, overdischarge mode, overcurrent mode: OFF
Discharge control FET (N-ch) control output pin
2
GD
Normal mod, overcharge mode: H
Overdischarge mode, overcurrent mode: L
Overcurrent detection input pin
3
CS
Monitors discharge current equivalently by the voltage drop between discharge control FET source
and drain. Stops discharge when voltage between CS pin and GND pin goes above overcurrent
detection threshold value, and holds until load is released.
4
5
GND
TD
VL
V
CC
VH
Ground pin, or lower cell load negative pole input pin.
Overcharge detection dead time setting pin
Dead time can be set by adding a capacitor between TD and GND pins.
Battery intermediate potential input pin
Connection pin for lower cell positive electrode side and upper cell negative electrode side.
Power supply input pin
Upper cell positive electrode input pin
Functions
6
7
8
Note: Mode Descriptions
(1) Overcharge mode
Either H cell or L cell battery voltage exceeds overcharge detection voltage. Overcharge detection
operation delay can be set by the dead time setting pin.
(2) Normal mode
Both H and L cell battery voltages exceed overdischarge detection voltage and are less than
overcharge detection voltage.
(3) Overdischarge mode
Either H or L cell battery voltage is less than overdischarge detection voltage.
Overdischarge detection dead time is set internally. Overdischarge mode is released when charging
causes voltage to rise above overdischarge detection voltage. Also, when battery voltage goes above
overdischarge release voltage, it resets without charging, but the value is set high. (This function is
included in case charging can not be detected. Also, this release voltage has a temperature coefficient
of -6mV/°C.)
(4) Overcurrent mode
Voltage between CS and GND exceeds overcurrent detection voltage during discharge.
MITSUMI
Protection of Lithium-Ion Batteries MM1412
Absolute Maximum Ratings
(Ta=25°C)
Symbol
T
STG
T
OPR
V
CC
max.
V
OC
max.
V
CS
max.
Pd
Ratings
-40~+125
-20~+70
-0.3~+18
-0.6~V
CC
-0.6~V
CC
300
Unit
°C
°C
V
V
V
mW
Item
Storage temperature
Operating temperature
Power supply voltage
OC pin impressed voltage
CS pin impressed voltage
Allowable loss
Recommended Operating Conditions
Item
Operating temperature
Operating power supply voltage
Symbol
T
OPR
V
OP
Ratings
-20~+70
+0.9~+18
Unit
°C
V
Electrical Characteristics
(Except where noted otherwise, Ta=25°C)
Item
Symbol
Measurement conditions
Min. Typ. Max. Unit
Overcharge detection voltage
V
OC
Ta=0°C~50°C
4.325 4.350 4.375 V
Overcharge detection hysteresis voltage
V
OC
170 220 270 mV
Overdischarge detection voltage
V
OD
2.20 2.30 2.40
V
Consumption current 1
I
VH1
V
H
=V
L
=1.0V V
CS
=1.4V
0.1
µA
Consumption current 2
I
VH2
V
H
=V
L
=1.9V V
CS
=3.2V
0.5
0.8
µA
Consumption current 3
I
VH3
V
H
=V
L
=3.5V
15.0 20.0 µA
Consumption current 4
I
VH4
V
H
=V
L
=4.5V, R
OC
=270kΩ
150
µA
V
H
=V
L
=3.5V
-0.3
0
0.3
µA
VL pin input current
I
VL
Overdischarge release voltage
V
DF
Discharge resume by voltage rise
3.30 3.50 3.70
V
GD pin H output voltage
V
GDH
V
H
=V
L
=3.5V, IL=-10µA
V
H
-0.3 V
H
-0.2
V
GD pin L output voltage
V
GDL
V
H
=V
L
=3.5V, IL=10µA
0.2
0.3
V
OC pin output current
I
OCH
V
H
=V
L
=4.5V
30
150
µA
Overcurrent detection threshold value
V
CS1
135 150 165 mV
Overcurrent short threshold value
V
CS2
When both battery pack pins are shorted 0.35 0.45 0.55
V
Overcurrent release
Load release: Load of 5MEGΩ or more between both battery pack pins
Overcurrent detection delay time 1
t
OC
1
7
12
18
mS
Overcurrent detection delay time 2
t
OC
2
30
100
uS
*
1
Overdischarge detection delay time
t
OD
8
13
20
mS
Overcharge detection dead time
t
OCH
C
TC
=0.18µF
0.5
1.0
1.5
S
Start-up voltage
V
ST
V
H
=V
L
=2.5V
-0.24 -0.12 -0.04 V
Note 1: Overcurrent short mode delay time (overcurrent delay time 2) is IC response speed.
In actual use, the time for discharging the discharge control FET gate capacity is added.
Also, when voltage change is large due to excess current, the IC internal bias current may turn off
temporarily, causing response time to lengthen. Select the time constant for the capacitor
connected to the power supply pin so that power supply fluctuation is more than 100µS/1V.
Note 2: Calculate overcharge dead time according to the following formula:
Overcharge detection dead time: t
ALM
- 5.55 C
TD
[S]
[C
TD
: external capacitor, Unit:µF]
MITSUMI
Protection of Lithium-Ion Batteries MM1412
Measuring Circuit
Measuring Circuit 1
(V
OC
, V
OC
, V
OD
, V
DF
, V
ST
, V
CS
, I
DCH
, V
GDH
, V
GDL
)
Measuring Circuit 2
(t
OC
, t
OD
, t
OCH
)
Note :
0.2V
1V/100µS
2.5V
0V
1V/100µS
4.5V
CS
V
L
2.0V
V
OD
V
L
4.0V
V
OC
GD
t OC
GD
OC
t OC
t OCH
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