MITSUMI

Protection of Lithium-Ion Batteries MM1412

Protection of Lithium-Ion Batteries

Monolithic IC MM1412

Outline

This IC protects lithium ion batteries in the event of overcharge, overdischarge and overcurrent. It has the

following two functions: an overcurrent detection function that turns the external FET-SW off when a problem

occurs during charging, etc. and excess voltage is impressed on each battery for longer than a certain time,

and an overdischarge detection function that turns the external FET-SW off when battery voltage drops below

a certain voltage during discharge, in order to prevent battery overdischarge. When these functions operate,

the IC is put into low consumption current mode. It also has an overcurrent detection function that turns the

FET-SW off when excess current flows due to a short or the like.

Features

1. Consumption current (during overcharge)

CELL

= 4.5 R

= 270 k

150µA typ.

2. Consumption current (normal)

CELL

= 3.5V

15µA typ.

3. Consumption current (during overdischarge)

CELL

= 1.9V

0.5µA typ.

4. Consumption current (during overdischarge)

CELL

= 1.0V

0.1µA max.

5. Overcharge detection voltage (Ta = 0°C ~ 50°C)

435 ± 25mV (detected for each cell)

6. Hysteresis voltage

220mV ± 50mV (detected for each cell)

7. Overdischarge detection voltage

2.30 ± 0.1V (detected for each cell)

8. Overdischarge release voltage

3.50V ± 0.2V (detected for each cell)

9. Overcurrent detection threshold

150mV ± 15mV

10. Reset after overcurrent detection

Load open

11. Operating limit voltage

0.9V max.

Package

VSOP-8A

SOP-8C

SOP-8E

MITSUMI

Model

Package

SOP-8C, E VSOP-8A

4.350±0.025

220±50

2.3±0.1

3.5±0.2

150±15

4.295±0.025

2.3±0.1

3.5±0.2

150±15

4.250±0.025

300±50

2.3±0.1

3.5±0.2

150±15

4.250±0.025

220±50

2.0±0.1

3.1±0.2

150±15

4.300±0.025

220±50

2.0±0.1

3.1±0.2

140±15

MM1412

4.225±0.025

2.3±0.1

3.5±0.2

150±15

4.250±0.025

150±50

4.5±0.2

150±15

4.350±0.025

220±50

2.3±0.1

3.5±0.2

100±15

4.125±0.025

2.3±0.1

3.5±0.2

150±15

4.125±0.025

2.0±0.1

3.1±0.2

100±15

4.190±0.025

2.0±0.1

3.1±0.2

100±15

4.300±0.025

220±50

2.0±0.1

3.1±0.2

75±15

Overcharge

detection

voltage (V)

Overcharge

detection voltage

temperature

conditions

Overcharge

detection

hysteresis

voltage (V)

Overdischarge

detection

voltage (V)

Overdischarge

reset

voltage (V)

Overcurrent

detection

voltage (mV)

Series Table

Temperature conditions A: Ta=-25 ~ 75°C, B: Ta=-20 ~ 70°C, C: Ta=0 ~ 50°C,

D: Ta=0 ~ 40°C, E: Ta=-20 ~ 25°C

MITSUMI

Protection of Lithium-Ion Batteries MM1412

Pin Description

Pin No. Pin name

Functions

Overcharge detection output pin

PNPT

open collector output

Overcharge mode: ON

Normal mode, overdischarge mode, overcurrent mode: OFF

Discharge control FET (N-ch) control output pin

Normal mod, overcharge mode: H

Overdischarge mode, overcurrent mode: L

Overcurrent detection input pin

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.

GND

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

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

Recommended Operating Conditions

Electrical Characteristics

(Except where noted otherwise, Ta=25°C) Models listed MM1412A

Item

Symbol

Ratings

Unit

Operating temperature

OPR

-20~+70

°C

Operating power supply voltage

+0.9~+18

Item

Symbol

Measurement conditions

Min. Typ. Max. Unit

Overcharge detection voltage

Ta=0°C~50°C

4.325 4.350 4.375

Overcharge detection hysteresis voltage

170

220

270

Overdischarge detection voltage

2.20

2.30

2.40

Consumption current 1

VH1

=1.0V V

=1.4V

0.1

µA

Consumption current 2

VH2

=1.9V V

=3.2V

0.5

0.8

µA

Consumption current 3

VH3

=3.5V

15.0

20.0

µA

Consumption current 4

VH4

=4.5V, R

=270k

150

µA

VL pin input current

=3.5V

-0.3

0.3

µA

Overdischarge release voltage

Discharge resume by voltage rise

3.30

3.50

3.70

GD pin H output voltage

GDH

=3.5V, IL=-10µA

-0.3 V

-0.2

GD pin L output voltage

GDL

=3.5V, IL=10µA

0.2

0.3

OC pin output current

OCH

=4.5V

150

µA

Overcurrent detection threshold value

CS1

135

150

165

Overcurrent short threshold value

CS2

When both battery pack pins are shorted

0.35

0.45

0.55

Overcurrent release

Load release: Load of 5MEG

or more between both battery pack pins

Overcurrent detection delay time 1

Overcurrent detection delay time 2

100

µs

Overdischarge detection delay time

Overcharge detection dead time

OCH

=0.18µF

0.5

1.0

1.5

Start-up voltage

=2.5V

-0.24 -0.12 -0.04

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

[s]

: external capacitor, Unit:µF]

Item

Symbol

Ratings

Unit

Storage temperature

STG

-40~+125

°C

Operating temperature

OPR

-20~+70

°C

Power supply voltage

max.

-0.3~+18

OC pin impressed voltage

max.

-0.6~V

CS pin impressed voltage

max.

-0.6~V

Allowable loss

300

Absolute Maximum Ratings

MITSUMI

Protection of Lithium-Ion Batteries MM1412

MITSUMI

Timing Chart

Description

Dischage
control
dead time
setting

Overcharge

Overdischarge

Overcharge

Overdischarge

Gate off

Keep cirquit

Over current
dead time

Open load

Overcharge

Over load

Charge sensing

dead time

Overdischarge
dead time

HI-impedance

Power down

Power

down

Short load

Overdischarge

detection

Overdischarge

Keep overcharge

Overdischarge

dead time

This IC is a lithium ion battery (2-cell in-series type) protection IC. It has built-in overcharge detection,

overdischarge detection and overcurrent detection circuits, and controls the FET (external N-MOS FET) that

controls charge and discharge.

The operation modes can be divided broadly into four, as follows.

1) Overcharge mode

The battery voltage of either the H or L cell goes above overcharge detection voltage. Detection operation

delay for overcharge detection can be set with the dead time setting pin.

2) Normal mode

The battery voltage of both H and L cells is above overdischarge detection voltage and below overcharge

detection voltage.

3) Overdischarge mode

The battery voltage of either the H or L cell drops below overdischarge detection voltage. Dead time for

overdischarge detection is set internally. Overdischarge mode is released when charging takes place and

the voltage goes above overdischarge detection voltage. Also, reset will occur even without charging if

battery voltage goes above overdischarge release voltage, but the set value is high. (This function is

provided as a measure for cases when charging can not be detected. Further, this release voltage has a

temperature coefficient of -6mV/°C.)

4) Overcurrent mode

The voltage between CS-GND goes above overcurrent detection voltage during discharge.

MITSUMI

Protection of Lithium-Ion Batteries MM1412

Characteristics

0.001

0.01

0.1

0.001

0.01

0.1

External capacitance (C

)

Overcharge detection time (S)

Overcharge Detection Time (Dead Time)

Note: Dead time can be calculated according to the following formula:

=5.55 C

[S]

=Overcharge Detection Time

=External Capacitor···Unit : µF

The above specifications are representative, and are not guaranteed values.

Application Circuit

Note: Applicable circuits shown are typical examples provided for reference purposes. Mitsumi cannot

assume responsibility for any problems arising out of the use of these circuits or for any infringement of

third party patent and other right due to same.

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ÐÐ»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: MM1412