BATTERY PROTECTION IC WITH ALARM FUNCTION FOR 1-CELL PACK

S-82T1A Series

Rev.1.0_00

18

2. 2

VCL = VCU (Product in which overcharge release voltage is the same as overcharge detection voltage)

When the battery voltage becomes higher than VCU during charging in the normal status and the condition continues

for the overcharge detection delay time (tCU) or longer, the charge control FET is turned off and charging is stopped.

This status is called the overcharge status.

In the case that the VM pin voltage is equal to or higher than 0.35 V typ. and the battery voltage falls below VCU, this

IC releases the overcharge status.

When the discharge is started by connecting a load after the overcharge detection, the VM pin voltage rises by the Vf

voltage of the internal parasitic diode than the VSS pin voltage, because the discharge current flows through the

parasitic diode in the charge control FET. If this VM pin voltage is equal to or higher than 0.35 V typ., this IC releases

the overcharge status when the battery voltage is equal to or lower than VCU.

Caution 1. If the battery is charged to a voltage higher than VCU and the battery voltage does not fall below

VCU even when a heavy load is connected, discharge overcurrent detection and load short-

circuiting detection do not function until the battery voltage falls below VCU. Since an actual

battery has an internal impedance of tens of m

Ω, the battery voltage drops immediately after a

heavy load that causes overcurrent is connected, and discharge overcurrent detection and load

short-circuiting detection function.

2. When a charger is connected after overcharge detection, the overcharge status is not released

even if the battery voltage is below VCL. The overcharge status is released when the discharge

current flows and the VM pin voltage goes over 0.35 V typ. by removing the charger.

3.

Alarm status

When the battery voltage becomes higher than the alarm status detection voltage (VAU) during charging in the normal

status and the condition continues for the alarm status detection delay time (tAU) or longer, AO pin outputs the alarm

signal. This status is called the alarm status.

3. 1

With charge control function

When the alarm status continues for 20 s typ. or longer, the charge control FET is turned off and charging is stopped.

3. 2

Without charge control function

Charging is not stopped even if the alarm status continues for 20 s typ. or longer.