S-8252AAA-M6T1U Datasheet, PDF (17/36 Pages) Seiko Instruments Inc – BATTERY PROTECTION IC

Rev.3.2_00
BATTERY PROTECTION IC FOR 2-SERIAL-CELL PACK
S-8252 Series
7. 0 V battery charge function "available"
This function is used to recharge a connected battery whose voltage is 0 V due to self-discharge. When the 0 V
battery charge starting charger voltage (V_0CHA) or a higher voltage is applied between the EB+ and EB− pins by
connecting a charger, the charging control FET gate is fixed to the V_DD potential.
When the voltage between the gate and source of the charging control FET becomes equal to or higher than the
threshold 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 V_DU, the S-8252 Series enters the normal
status.
Caution
1. Some battery providers do not recommend recharging for a completely self-discharged battery.
Please ask the battery provider to determine whether to enable or inhibit the 0 V battery charge
function.
2. The 0 V battery charge function has higher priority than the charge overcurrent detection
function. Consequently, a product in which use of the 0 V battery charge function is enabled
charges a battery forcibly and the charge overcurrent cannot be detected when the battery
voltage is lower than V_DL.
8. 0 V battery charge function "unavailable"
This function inhibits charging when a battery that is internally short-circuited (0 V battery) is connected. When the
battery voltage is the 0 V battery charge inhibition battery voltage (V_0INH) or lower, the charging control FET gate is
fixed to the EB− pin voltage to inhibit charging. When the battery voltage is V_0INH or higher, charging can be
performed.
Caution Some battery providers do not recommend recharging for a completely self-discharged battery.
Please ask the battery provider to determine whether to enable or inhibit the 0 V battery charge
function.
9. Delay circuit
The detection delay times are determined by dividing a clock of approximately 4 kHz by the counter.
Remark t_DIOV and t_SHORT start when V_DIOV is detected. When V_SHORT is detected over t_SHORT after V_DIOV, the S-8252
Series turns the discharging control FET off within t_SHORT from the time of detecting V_SHORT.
V_DD
DO pin
V_SS
VM pin
V_DD
V_SHORT
V_DIOV
V_SS
t_SHORT
t_D
0 ≤ t_D ≤ t_SHORT
Time
Figure 10
Time
17