S-8261 Seiko Instruments, S-8261 Datasheet - Page 20

• Manufacturer Part Number: S-8261
• Description: Battery Protection IC for Single-Cell Pack
• Manufacturer: Seiko Instruments

20
BATTERY PROTECTION IC FOR SINGLE-CELL PACK
S-8261 Series
7. Delay Circuits
8. DP Pin
9. 0 V Battery Charging Function “Available”
Remark 1. The detection delay time for overcurrent 2 (t
The detection delay times are determined by dividing a clock of the approximately 3.5 kHz with the
counter.
The DP pin is a test pin for delay time measurement and it should be open in the actual application. If a
capacitor whose capacitance is larger than 1000 pF or a resister whose resistance is less than 1 MΩ is
connected to this pin, error may occur in the delay times or in the detection voltages.
This function is used to recharge the connected battery whose voltage is 0 V due to the self-discharge.
When the 0 V battery charge starting charger voltage (V
EB− pin by connecting a charger, the charging control FET gate is fixed to VDD pin voltage. When the
voltage between the gate and source of the charging control FET becomes equal to or higher than the
turn-on voltage due to the charger voltage, the charging control FET is turned on to start charging. At
this time, the discharging control FET is off and the charging current flows through the internal parasitic
diode in the discharging control FET. When the battery voltage becomes equal to or higher than the
overdischarge release voltage (V
Caution
Remark The 0 V battery charge function has higher priority than the abnormal charge current detection
2. When the overcurrent is detected and continues for longer than the overdischarge detection
Some battery providers do not recommend charging for completely self-discharged
battery. Please ask battery providers before determine whether to enable or inhibit the
0 V battery charging function.
function. Consequently, a product with the 0 V battery charging function is enabled charges
a battery forcibly and abnormal charge current cannot be detected when the battery voltage is
low.
delay time (t
when the battery voltage falls below the overdischarge detection voltage (V
battery voltage falls below the overdischarge detection voltage (V
the S-8261 Series turns the discharging control FET off by the overcurrent detection. In this
case the recovery of the battery voltage is so slow that if the battery voltage after the
overdischarge detection delay time (t
voltage (V
the overcurrent 1 (V
(V
detection of overcurrent 1 (V
each detection.
SHORT
) is detected over the detection delay time for each of them (= t
DO pin
VM pin
DL
), the S-8261 Series shifts to the power-down condition.
DL
) without releasing the load, the condition changes to the power-down condition
Overcurrent 2 detection delay time (t
V
V
V
V
V
V
DD
SS
DD
IOV2
IOV1
SS
IOV1
DU
), the S-8261 Series enters the normal condition.
) is detected. When the overcurrent 2 (V
Seiko Instruments Inc.
IOV1
), the S-8261 Series turns the FET off within t
DL
) is still lower than the over discharge detection
Figure 6
IOV2
0CHA
) and load short-circuiting (t
) or higher is applied between EB+ pin and
IOV2
)
t
D
0≦t
IOV2
DL
) due to the overcurrent,
) or load short-circuiting
D
≦t
IOV2
IOV2
or t
SHORT
Time
Time
DL
IOV2
SHORT
Rev.1.9
). When the
) start when
or t
) after the
SHORT
_00
of