SC121
LI+ BATTERY PROTECTION CIRCUIT
DESCRIPTION
SC121 is a LI+ battery protection circuit. It is suitable for protecting LI+
battery against damage from over charge, over discharge, and over
current. It contains high accurate voltage detection and delay circuits.
FEATURES
* Low supply current
* Over-charge detect 4.28V, Over-charge release 4.10V.
* Over-discharge detect 2.50V, Over-discharge release 2.90V.
* Over-current detect 0.15V, Short Current detect 1.00V.
* Overcharge/over-discharge/over-current detection delay
* Charger detection
* Reset resistance for over current protection
* Wide supply voltage range
* Small package
APPLICATIONS
* Protection IC for One-Cell LI+
Battery Pack
ORDERING INFORMATION
Part No.
SC121NTR
SC121NATR
SC121NGTR
SC121NAGTR
Package
121N
SOT-23-6
Marking
121NA
121NG
121NAG
Material
Pb free
Pb free
Halogen free
Halogen free
Package Type
Tape & Reel
Tape & Reel
Tape & Reel
Tape & Reel
HANGZHOU MICROELECTRONICS CO.,LTD
Http:// www.silan.com.cn
REV:1.6
2009.07.20
Page 1 of 9
SC121
BLOCK DIAGRAM
ABSOLUTE MAXIMUM RATING
Characteristics
Supply Voltage
OC Output Pin Voltage
OD Output Pin Voltage
CSI Input Pin Voltage
Operating Temperature Range
Storage Temperature Range
Symbol
V
DD
V
OC
V
OD
V
CSI
T
OPR
T
STG
Value
V
SS
-0.3 ~ V
SS
+12
V
DD
-15 ~ V
DD
+0.3
V
SS
-0.3 ~ V
DD
+0.3
V
DD
-15 ~ V
DD
+0.3
-40 ~ + 85
-40 ~ +125
Unit
V
V
V
V
°C
°C
ELECTRICAL CHARACTERISTICS
(Tamb=25°C, unless otherwise specified)
Characteristics
Operating Voltage
Operating Voltage
Current Consumption
Supply Current
Power Down Current
Detection Voltage
Over Charge Detection Voltage
Over Charge Release Voltage
Over Discharge Detection Voltage
Over Discharge Release Voltage
V
OCU
V
OCR
V
ODL
V
ODR
4.24
4.05
2.40
2.80
4.28
4.10
2.50
2.90
4.32
4.15
2.60
3.00
V
V
V
V
I
DD
I
PD
V
DD
=3.9V
V
DD
=2.0V
3.0
0.3
6.0
0.6
µA
µA
V
DD
1.8
8.0
V
Symbol
Status
Min.
Typ.
Max.
Unit
HANGZHOU MICROELECTRONICS CO.,LTD
Http:// www.silan.com.cn
REV:1.6
2009.07.20
Page 2 of 9
SC121
Characteristics
Over Current 1 Detection Voltage
Over Current 2(Short Current)Detection
Voltage
Over Current Reset Resistor
Charger Detection Voltage
Delay Time
Over Charge Detection Delay Time
Over Discharge Detection Delay Time
Over Current 1 Detection Delay Time
Over Current 2(Short Current)Detection
Delay Time
Other
OC Pin Output “ Voltage
H”
OC Pin Output “ Voltage
L”
OD Pin Output “ Voltage
H”
OD Pin Output “ Voltage
L”
0 V battery charge starting charger
voltage
PIN CONFIGURATION
V
oh1
V
ol1
V
oh2
V
ol2
V
OCHA
SC121NA
1.55
V
DD
-0.1 V
DD
-0.02
0.01
V
DD
-0.1 V
DD
-0.02
0.01
0.1
0.1
V
V
V
V
V
T
OC
T
OD
T
OI1
T
OI2
V
DD
=3.6V~4.4V
V
DD
=3.6V~2.0V
V
DD
=3.6V
V
DD
=3.6V
150
80
5
340
200
13
5
500
300
20
50
ms
ms
ms
µs
Symbol
V
OI1
V
OI2
R
short
V
CH
V
DD
=3.6V
V
DD
=3.6V
Status
Min.
0.13
0.80
400
-0.8
Typ.
0.15
1.00
500
-0.5
Max.
0.17
1.20
600
-0.2
Unit
V
V
kΩ
V
PIN DESCRIPTIONS
PIN No.
1
2
3
4
5
6
Symbol
OD
CSI
OC
TD
V
DD
V
SS
I/O
O
I/O
O
I
I
I
Description
FET gate connection pin for discharge control.
Input pin for current sense, charger detect.
FET gate connection pin for charge control.
Test pin for reduce delay time.
Positive power input pin.
Negative power input pin.
HANGZHOU MICROELECTRONICS CO.,LTD
Http:// www.silan.com.cn
REV:1.6
2009.07.20
Page 3 of 9
SC121
FUNCTION DESCRIPTIONS
Normal Status
If V
ODL
<V
DD
<V
OCU
and V
CH
<V
CSI
<V
OI1
, M1 and M2 are both turned on (refer to Typical Application Circuits).
The charging and discharging processes can be operated normally.
Overcharge Detection
When enter charging from normal status, the battery voltage can be detected from V
DD
. When the battery is in
overcharge status, V
DD
is larger than V
OCU
over a delay time of T
OC
, M2 is to be turned off.
Release of Overcharge Status
There are two ways to return to normal status from overcharge status.
•
If the battery is self discharging and V
DD
<V
OCR
occurs, M2 is to be turned on and back to normal status.
•
Remove the charger and connected to a load. If V
OCR
<V
DD
<V
OCU
and V
CSI
>V
OI1
occurs, M2 is to be turned
on and back to normal status.
Over discharge Detection
When enter discharging from normal status, the battery voltage can be detected from V
DD
. When the battery is
in over discharge status, V
DD
is smaller than V
ODL
over a delay time of TOD; M1 is to be turned off. In the
meanwhile, CSI is pulled to V
DD
by way of internal resistor RCSID. If V
CS
I>V
OI2
, the protection IC enters into
Power-down mode. (Its current consumption is lower than 0.3µA).
Release of Power-down mode
A charger is connected while the battery remains in Power-down mode. If V
CH
<V
CSI
<V
OI2
and V
DD
<V
ODR
occur, M1 is still off but it releases Power-down mode. If V
DD
>V
ODR
occurs, M1 is to be turned on and back to
normal status.
Charger Detection
If a charger is connected to the battery remained in Power-down mode, the voltages will become V
CSI
<V
CH
and V
DD
>V
ODL
. M1 is to be turned on and back to normal status.
Abnormal Charging Status
If a charger is connected to the battery in normal status, V
CSI
<V
CH
occurs over a delay time longer than TOC,
M2 is to be turned off.
Over Current/Short Current Detection
When the discharging current is too large during discharging under normal status and the voltage detected
from CSI is larger than V
OIX
(V
IO1
or V
IO2
) for over a certain delay time T
OIX
(T
IO1
or T
IO2
), it means the over
current/short current status occurred. M1 is turned off. CSI is pulled to V
SS
by way of an internal resistor RCSIS.
Release of Over Current/Short Current Status
While the protection IC remains in Over Current/Short Current status and load is removed or the impedance
between V
BAT
+ and V
BAT
- is larger than 500KΩ and V
CSI
<V
OI1
, M1 is to be turned on and back to normal status.
Note: when a battery is connected to a protection IC for the first time, the IC may not enter the normal status (not
dischargeable status). If this occurs, set the CSI pin voltage equal to the V
SS
voltage (short the CSI and
V
SS
pins or connect a charger) to enter the normal status.
HANGZHOU MICROELECTRONICS CO.,LTD
Http:// www.silan.com.cn
REV:1.6
2009.07.20
Page 4 of 9
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