s-8243bahft-tb-g Seiko Instruments Inc., s-8243bahft-tb-g Datasheet - Page 16

• Manufacturer Part Number: s-8243bahft-tb-g
• Description: Battry Protection Ic For 3-serial Or 4-serial Cell Pack
• Manufacturer: Seiko Instruments Inc.

16
BATTERY PROTECTION IC FOR 3-SERIAL OR 4-SERIAL CELL PACK
S-8243A/B Series
1. Battery protection circuit
Operation
Remark Refer to “
Battery protection protects batteries from overcharge and overdischarge, and also protects external FETs from
overcurrent.
1. 1 Normal status
1. 2 Overcharge status
1. 3 Overdischarge status
1. 4 Power down status
1. 5 Overcurrent status
When all of the battery voltages are in the range from V
value (the VMP pin voltage is lower than V
When any one of the battery voltages becomes higher than V
pin becomes high impedance and is pulled up to EB+ pin voltage by an external resistor, and the charging FET is
turned off to stop charging. The overcharge status is released when one of the following two conditions holds.
When any one of the battery voltages becomes lower than V
voltage becomes V
status.
After stopping discharging due to overdischarge status, the S-8243 enters power down status. In this status, almost
all circuits of the S-8243 are stopped to save current consumption. The current consumption becomes lower than
I
status, output pin voltages are fixed at the following levels.
The S-8243 has three overcurrent detection levels (V
times (t
becomes higher than a specified value (the voltage between V
continues for t
level to turn off the discharging FET to stop discharging, the COP pin becomes high impedance and is pulled up to
EB+ pin voltage by an external resistor to turn off the charging FET to stop charging, and the VMP pin is pulled up to
V
overcurrent detection delay times (t
The overcurrent status is released when the following condition holds.
PDN
DD
(a) All battery voltages become lower than V
(b) V
(a) COP
(b) DOP
(c) VREG
(d) VBATOUT
The power down status is released when the following condition holds.
The overdischarging status is released when the following condition holds.
(a) V
. In the power down status, the VMP pin is pulled down to V
voltage by the internal resistor R
(a) V
(a) All of the battery voltages are V
EB+ pin becomes higher. )
IOV1
DD
MP
connected.)
−V
> {V
, t
MP
MP
IOV2
>V
IOV1
IOV3
>V
IOV3
and t
IOV1
or longer, the S-8243 enters the overcurrent status in which the DOP pin voltage becomes V
Battery Protection IC Connection Example”.
/ (1−V
DD
High-Z
V
V
V
(A charger is connected, and charging starts.)
DD
SS
SS
(A load is connected, and discharging starts.)
level, and the discharging FET is turned off to stop discharging. This is the overdischarge
IOV3
IOV3
) corresponding to each overcurrent detection levels. When the discharging current
) × 3 / 5−2 / 5} × R
(Charging FET is turned off)
(Discharging FET is turned off)
(Voltage regulator circuit is off)
(Battery voltage monitor amp circuit is off)
IOV2
VDM
and t
Seiko Instruments Inc.
. Operation of two other overcurrent detection levels (V
DLn
IOV1
IOV3
or higher, and the VMP pin voltage is VDD / 2 or higher. (A charger is
), the charging and discharging FETs are turned on.
VDM
CUn
) is the same as that for V
+ V
(A load is released, and the impedance between the EB− and
DLn
IOV1
HCn
to V
.
, V
DLn
IOV2
CUn
CUn
and the state continues for t
SS
and the discharge current is lower than a specified
and the state continues for t
and V
DD
level by the internal R
and V
IOV3
IOV1
MP
) and three overcurrent detection delay
is greater than V
and t
IOV1
.
VSM
DL
resistor. In power down
or longer, the DOP pin
CU
IOV1
or longer, the COP
IOV2
) and the state
Rev.2.7
and V
IOV3
) and
_00
DD