MITSMI MM1292LF, MM1292JF, MM1292KF, MM1292CF, MM1292DF Datasheet

MITSUMI

Protection of Lithium Ion Batteries (two cells in series) MM1292

Protection of Lithium Ion Batteries (two cells in series)

Monolithic IC MM1292

Outline

2-Cell Protection ICs

This IC is for protecting a lithium ion battery from overcharging, excess discharging, and overcurrent. If
abnormalities occur during charging and excess voltage is applied, it has a function that turns off the external
FET switch when voltage is applied to each battery beyond a specified time (overcharging detection). It also
has a function that turns off the external FET switch when the voltage for each battery falls below a set
voltage, to prevent excess discharge when discharging the battery (discharging detection). At that time, the IC
is switched to low current consumption mode. Also, when there is a large current flow due to shorting or other
reasons, there is a function for turning off the external FET switch (overcurrent detection).
These functions comprise a protection circuit, with few external parts, for lithium ion batteries.

Model name

Overcharge protection Overdischarge protection Overcurrent

Detection voltage

Hysteresis

Detection voltage

Hysteresis

Detection voltage

MM1302A 4.25±0.05V 10mV 2.3V±0.1V 700mV 220±20mV
MM1292C 4.25±0.05V 200mV 2.4V±0.1V 600mV 150±15mV
MM1292D 4.35±0.05V 200mV 2.4V±0.1V 600mV 150±15mV
MM1302E 4.10±0.05V 10mV 2.4V±0.1V 600mV 150±15mV
MM1302F 4.35±0.05V 10mV None None
MM1302G 4.215±35V 10mV 2.3V±0.1V 700mV 220±20mV
MM1292H 4.30±0.05V 220mV 2.05V±0.1V 950mV 170±15mV
MM1292J 4.25±0.05V 220mV 2.4V±0.1V 600mV 150±15mV
MM1292K 4.25±0.05V 220mV 2.4V±0.1V 600mV 150±15mV
MM1292L 4.25±0.05V 220mV 2.2V±0.1V 800mV 100±10mV

Features

1. Current consumption (during overcharging) VCELL=4.5V 80µA typ.

2. Current consumption (normal) V

CELL=3.5V 13µA typ.

3. Current consumption (during excess discharging) V

CELL=1.9V 0.5µA typ.

4. Current consumption (during excess discharging) V

CELL=1.0V 0.1µA max.

5. Overcharge detection voltage (Ta=

-

20°C~+70°C)

4.25V±50mV (detection for each cell)

6. Hysteresis voltage

200mV±60mV (detection for each cell)

7. Excess discharge detection voltage 2.4V±0.1V (detection for each cell)

8. Discharge resumption voltage 3.0V±0.1V (detection for each cell)

9. Overcurrent detection voltage 150mV±15mV

10.Reset after overcurrent detection load release

11.Operating limit voltage 0.9V max.

Package

SOP-8C, SOP-8D(MM1292 F)

*

The box represents the rank resulting from the combination of protection functions.

MITSUMI

Protection of Lithium Ion Batteries (two cells in series) MM1292

Pin Assignment

1432

8567

SOP-8C/SOP-8D

1 OC

2 GD

3 N.C

4 GND

5 TD

6 VL

7 CS

8 VH

Pin Description

Pin No.

Pin Output Function

1 OC Output

2 GD Output

3 DS Input

4 GND Input

5 TD Input

6 VL Input

7 CS Input

8 VH Input

Output pin for control of the charging control FET. When voltage detected between

VH-VL or VL-GND goes over overcharge detection voltage (VALM), the output PNP-

TR (open collector output) is switched ON, and charging is prohibited by activating

the element (NPN-TR, or N-ch FET) that switches the charging control FET to OFF.

This operation continues until the voltage falls below VALM.

Output pin for driving the discharge control FET. When voltage detected between VH-

VL and VL-GND goes over excess discharge voltage (VS), this pin goes H. When

voltage detected between VH-VL and VL-GND falls below VS and the voltage between

CS-GND is more than the voltage detected for an overcurrent (VCS), it goes L.

Input pin for discharge detection. When voltage between DS-GND during charge

detection exceeds discharge detection voltage (VDS), OC output is switched OFF

and charge control FET is switched ON.

Negative connection pin for the low side battery. It is also the GND pin for this IC.

(The IC's reference power supply pin.)

Over charge detection output non-induction time setting pin. The capacitor connected

between TD-GND is charged with constant current (ITC) during over charging. When

TC pin voltage exceeds the threshold value (VTC), OC output is switched ON.

Positive connection pin for the low side battery, and negative connection pin for the

high side battery.

Overcurrent detection pin during discharge, and charging detection pin during

power down. It detects discharge current using the source drain voltage (voltage

between CS-GND) of discharge control FET. Also, when the battery is charged with

a current whose CS-GND voltage after power down exceeds the start-up voltage

(VST), the bias current is drained to the interior circuit and operating status results.

Positive connection pin for the high side battery, and the IC's current input pin.

Applications

1. Cellular phones

2. Movies

MITSUMI

Protection of Lithium Ion Batteries (two cells in series) MM1292

Block Diagram

Note 1. 45µA max. (current consumption during operation of overcharge detection section) flows to input

protection resistor R1.

Note 2. 0.3µA max. (when cells are balanced) flows to input protection resistor R2. When the cells are not

balanced, the current increases to wards correction.

Data intake
prohibition interval

Data intake prohibition interval

t2

t1

tOP

tST

Operating

interval

waiting interval

tOP

tST

Time

Average
current

30µA

5µA

Current

consumption

Current
consumption

Timing for setting non-induction time

V

CELL>4.25V

V

CELL<4.25V

Data processing

section

Non-induction
time

Overcharging
identification

Reset

VH
GC

VCS (battery-)