AiT Semiconductor Inc.
A4002
www.ait-ic.com
BATTERY MANAGEMENT
ONE CELL LITHIUM-ION/POLYMER BATTERY PROTECTION IC
charger detection voltage (VCHA). When an abnormal charge current flows into a battery in the overdischarge
condition, the A4002 consequently turns the charging control FET off and stops charging after the battery
voltage becomes the overdischarge detection voltage and the overcharge detection delay time (tCU) elapses.
Abnormal charge current detection is released when the voltage difference between VM pin and GND pin
becomes lower than the charger detection voltage (VCHA) by separating the charger. Since the 0V battery
charging function has higher priority than the abnormal charge current detection function, abnormal charge
current may not be detected by the product with the 0V battery charging function while the battery voltage is
low.
Load Short-circuiting Condition
If voltage of VM pin is equal or below short-circuiting protection voltage (VSHORT), the A4002 will stop
discharging and battery is disconnected from load. The maximum delay time to switch current off is tSHORT
.
This status is released when voltage of VM pin is higher than short protection voltage (VSHORT), such as when
disconnecting the load.
Delay Circuits
The detection delay time for overdischarge current 2 and load short-circuiting starts when overdischarge
current 1 is detected. As soon as overdischarge current 2 or load short-circuiting is detected over detection
delay time for overdischarge current 2 or load short-circuiting, the A4002 stops discharging. When battery
voltage falls below overdischarge detection voltage due to overdischarge current, the A4002 stop discharging
by overdischarge current detection. In this case the recovery of battery voltage is so slow that if battery
voltage after overdischarge voltage detection delay time is still lower than overdischarge detection voltage,
the A4002 shifts to power-down.
0V Battery Charging Function1 2 3
This function enables the charging of a connected battery whose voltage is 0V by self-discharge. When a
charger having 0V battery start charging charger voltage (V0CHA) or higher is connected between B+ and
B-pins, the charging control FET gate is fixed to VDD potential. When the voltage between the gate and the
source of the charging control FET becomes equal to or higher than the turn-on voltage by 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. If the
battery voltage becomes equal to or higher than the overdischarge release voltage (VDU), the normal condition
returns.
REV1.0
- JUN 2018 RELEASED -
- 7 -
AITSEMI [ AiT Semiconductor ]
