MITSUMI
IC for Control of Lithium-ion Betteries Charging MM1438
IC for Control of Lithium-ion Betteries Charging
Monolithic IC MM1438
Outline
This IC is used to control charging of lithium-ion batteries consisting of a single cell. It is a modification of the
previous MM1332 charging-control IC, with improved charging voltage accuracy and a smaller package.
Features
1. Charging voltage accuracy (Ta=25C)
25mV/cell
2. Charging voltage accuracy (Ta=0 to 50C)
30mV/cell
3. Consumption current (charging on)
250A typ.
4. Consumption current (charging off)
2A typ.
5. Low-voltage detection
2.15V typ.
6. Leakage current between CEL and CS
1A max.
Package
VSOP-8B
Applications
Pin Assignment
IC for control of lithium-ion batteries charging.
1
4
3
2
8
5
6
7
VSOP-8B
MITSUMI
1
GND
2
LV
3
SW2
4
SW1
5
V
CC
6
EXT
7
CEL
8
CS
MITSUMI
IC for Control of Lithium-ion Betteries Charging MM1438
MITSUMI
Block Diagram
Pin Description
Pin No. Pin name
I/O
Pin Description
1
GND
Input
Ground pin
2
LV
Output
Low voltage detection circuit output pin
ON with NPN-Tr open collector output at low voltage
3
SW2
Input
Low voltage detection circuit ON/OFF control input pin
SW2 = V
CC
: OFF, SW2 = GND: ON
4
SW1
Input
ON/OFF control input pin for the IC
SW1 = V
CC
: OFF, SW1 = GND: ON
5
V
CC
Input
Power supply input pin
6
EXT
Output
Charging control output pin Controls external PNP-Tr to control charging.
7
CEL
Input
Battery voltage input pin
Detects battery voltage and controls rated voltage to the prescribed voltage value.
Current detection pin
8
CS
Input
Detects current by drop in external resistor voltage and controls rated current.
Current value can be set at 0.1V/R1 typ.
MITSUMI
IC for Control of Lithium-ion Betteries Charging MM1438
Absolute Maximum Ratings
(Ta=25C)
Item
Symbol
Ratings
Unit
Storage temperature
T
STG
-40~+125
C
Operating temperature
T
OPR
-20~+70
C
Power supply voltage
V
CC
max.
-0.3~+18
V
CFL pin input voltage
V
CEL
max.
-0.3~+13
V
SW input voltage
V
SW
-0.3~V
CC
+0.3
V
Allowable loss
Pd
300
mW
Recommended Operating Conditions
Item
Symbol
Ratings
Unit
Operating temperature
T
OPR
-20~+70
C
Charging control operating voltage
V
OPR
2.5~+17
V
Electrical Characteristics
(Except where noted otherwise, Ta=25C, V
CC
=5V, SW3 : A, SW6 : A, SW7 : A)
Item
Symbol
Measurement conditions
Min. Typ. Max. Unit
Consumption current 1
I
CC1
VSW1=VSW2=0V (Charge : ON)
250
400
A
Consumption current 2
I
CC2
VSW1=VSW2=V
CC
(Charge : OFF)
2
10
A
Output voltage 1
V
O1
Ta=25C
4.100 4.125 4.150
V
Output voltage 2
V
O2
Ta=0~50C
4.095 4.125 4.155
V
Current limit
V
CL
90
100
110
mV
Inflow current between
I
CEL1
3.0
5.0
7.0
A
CEL-CS during operation
Leak current between CEL-CS
I
CEL2
V
CC
=0V or OPEN
0.01
1
A
SW1 input current
I
SW1
20
30
A
SW1 input voltage L
V
L1
Charge : ON
-0.3
2.0
V
SW1 input voltage H
V
H1
Charge : OFF
V
CC
-0.1
V
CC
+0.3
V
Low voltage detection voltage
L
V
2.0
2.15
2.3
V
SW2 input current
I
SW2
20
30
A
SW2 input current L
V
L2
Low voltage detection circuit: ON
-0.3
2.0
V
SW2 input current H
V
H2
Low voltage detection circuit: OFF
V
CC
-1.0
V
CC
+0.3
V
Low voltage detection
I
LV
0.5
A
output leak current
Low voltage detection
V
LV
I
SINK
=1mA
0.2
0.4
V
output saturation voltage
EXT pin inflow current
I
EXT
10
20
mA
EXT pin output voltage
V
EXT
For no load
0.3
V
CC
-0.3
V
Note 1: Please insert a capacitor of several F between power supply and ground when using.
Note 2: Be sure that CS pin potential does not fall below -0.5V.
Note 3: If the IC is damaged and control is no longer possible, its safety can not be guaranteed. Please
protect with something other than this IC.
Note: Operating voltage minimum value is during rated current control.
MITSUMI
IC for Control of Lithium-ion Betteries Charging MM1438
Measuring Circuit
MITSUMI
IC for Control of Lithium-ion Betteries Charging MM1438
MITSUMI
Measurement Procedures
(Except where noted otherwise, Ta=25C, V
CC
=5V, SW3 : A, SW6 : A, SW7 : A)
Item
Measurement Procedures
Consumption current 1
V3 = V
CC
, V4 = 0V. Next, measure A5 current value Icc1 when V3 is changed
from V
CC
0V.
Consumption current 2
V3 = Vd = V
CC
. Measure A6 current value I
CC2
at this time.
Output voltage
V3 = V
CC
, V4 = 0V. Measure T7 voltage V
O
at this time.
Current limit
V3 = Vcc, V4 = 0V. Set V7 voltage 1V lower than T7 (output voltage) potential
and set SW7 to B. Measure T8 voltage V
CL
at this time.
Inflow current between
V3 = V
CC
, V4 = 0V, SW6: C. V7 = 4.5V, SW7: B. Measure A7 current value
CEL-CS during operation
I
CEL1
at this time.
Leak current between CEL-CS
V3 = V4 = V
CC
= 0V, SW6: C. V7 = 4.5V, SW7: B. Measure A7 current value
I
CEL2
at this time.
SW1 input current
Measure A4 current value I
SW1
when V4 = 0V.
SW1 input voltage
V3 = V
CC
. Charge: ON (V
L1
) when V4 potential is varied and T7 voltage is the
prescribed output voltage; Charge OFF (V
H1
) when 0 ~ 0.05V.
V3 = V4 = 0V. Set V7 voltage 1V lower than T7 (output voltage) potential, and
SW7: B.
Low voltage detection voltage
Next gradually lower V7 voltage; V7 voltage is L
V
when A7 current value is
within 10A.
SW2 input current
Measure A3 current value I
SW2
when V3 = 0V.
SW2 input voltage
V4 = 0V, V7 = 1V, SW7: B. Low voltage detection circuit: ON (V
L2
) when V3
voltage is varied and A7 current value is within 10A; low voltage detection
circuit: OFF (V
H2
) otherwise.
Low voltage detection
V3 = V
CC
, V4 = 0V. Measure A2 current value I
LV
when V3 is changed from
output leak current
Vcc 0V.
Low voltage detection
V3 = V4 = 0V. SW3: B, SW7: B. Measure T2 voltage V
LV
when V7 voltage is 0V.
output saturation voltage
EXT pin inflow current
V3 = V4 = 0V. SW6: B, SW7: B, V6 = 4V, V7 = 3V. Measure A6 current value I
EXT
.
EXT pin output voltage
V3 = V4 = 0V. SW6: C, SW7: B. T6 voltage when V7 = 3V and V7 = 5V is V
EXT
.
MITSUMI
IC for Control of Lithium-ion Betteries Charging MM1438
MITSUMI
Timing Chart
Battery connection and SW1: ON
V
CC
OFF
OFF
ON
ON
SW1
CEL
CS
LV
CEL
CS
LV
Rated voltage mode
Charging ON
Rated current mode
Charging OFF
Charging OFF
Normal charging
Battery low voltage
(2V or less)
0
0
0
0
0
0
0
0
L
L
H
100mV
(SW2 : L)
Application Circuit
MITSUMI
IC for Control of Lithium-ion Betteries Charging MM1438
Characteristics
4.15
4.10
4.05
0
5
10
18
15
(Ta=25
C)
Power supply voltage (V)
Output voltage (V)
Output voltage vs Power supply voltage
4.15
4.10
4.05
-25
0
25
75
50
(V
CC
=5V)
Ambient temperature (
C)
Output voltage (V)
Output voltage vs Ambient temperature
110
105
100
95
90
0
5
10
18
15
(Ta=25
C)
Power supply voltage (V)
CS pin voltage (mV)
CS pin voltage vs Power supply voltage
110
105
100
95
90
-25
0
25
75
50
(V
CC
=5V)
Ambient temperature (
C)
CS pin voltage (mV)
CS pin voltage vs Ambient temperature
5
4
3
2
1
0
0
5
10
25
15
20
(Ta=25
C)
LV pin inflow current (mA)
LV pin voltage (V)
LV pin voltage vs LV pin inflow current
200
150
100
50
0
2
2.1
2.2
2.5
2.3
2.4
(Ta=25
C,V
CC
=5V, at low voltage detection)
Output voltage (V)
CS pin voltage (mV)
CS pin voltage vs Output voltage
5
4
3
2
1
0
0
5
10
30
15
20
25
(Ta=25
C,V
CC
=5V)
EXT pin inflow current (mA)
EXT pin voltage (V)
EXT pin voltage vs EXT pin inflow current
PDF 
ZIP