MB3836 Datasheet, PDF (17/28 Pages) Fujitsu Component Limited. – Li-Ion Battery Protection IC

MB3836
2. Over-charge Detection Block, Discharge Detection Block, and Cell Voltage Input Block
• When battery is discharged after detection of an over-charge or re-discharged after detection of an over-charge
by recharging
If a cell voltage reaches or exceeds the over-charge detection voltage (4.325 V Typ), the COUT terminal (pin 2)
goes “H” level to turn off the Pch MOS FET for external charge control after a delay time (23 ms Typ) managed
by the capacitor (COVT) connected between the COVT terminal (pin 14) and GND. This stops charging the battery
and puts it into the over-charge detected state.
When a discharge is started in the over-charge detected state, the OCV terminal voltage is lowered by the body
diode voltage of the Pch MOS FET for external charge control. When the potential difference between the VCC
terminal and OCV terminal (pin 1) becomes 300 mV or more, the COUT terminal (pin 2) goes “L” level to turn
on the Pch MOS FET for external charge control and the cell voltage input block switch is turned off at the same
time.
An over-charge caused by recharging can be detected even with cell voltages remaining above the over-charge
release voltage (4.125 V Typ).
Discharge start↓
↓Charge start
↓Discharge start
Cell voltage
Cell voltage
input current
COVT terminal
VTH (4.325 V)
VH (0.2 V)
(4.125 V)
(45 µA)
(0 µA)
(6.26 V)
COUT terminal
OCV terminal
(VCC)
VTH (VCC − 0.3 V)
tD (23 ms)
Figure 4
tD (23 ms)
17