S-8244 datasheet(13/28 Pages) ABLIC

13 / 28 page

BATTERY PROTECTION IC FOR 1-SERIAL TO 4-SERIAL-CELL PACK (SECONDARY PROTECTION)

Rev.7.0_00

S-8244 Series



Operation

Remark

Refer to “  Battery Protection IC Connection Example”.

1. Overcharge Detection

• Product with CMOS output active “H”, Nch open drain output active “H”

During charging in the normal status, the voltage of one of the batteries exceeds overcharge detection voltage

(VCU), and this status is maintained for overcharge detection delay time (tCU) or longer, CO gets “H”. This is

overcharge status. Connecting a FET to the CO pin enables charge-control and the second protect.

In this case, the IC maintains the overcharge status until the voltage of each of the batteries decreases, to the

overcharge hysteresis voltage (VCD) from the overcharge detection voltage (VCU).

• Product with CMOS output active “L”, Nch open drain output active “L”, Pch open drain output active “L”

During charging in the normal status, the voltage of one of the batteries exceeds overcharge detection voltage

(VCU), and this status is maintained for overcharge detection delay time (tCU) or longer, CO gets “L”. This is

overcharge status. Connecting a FET to the CO pin enables charge-control and the second protect.

In this case, the IC maintains the overcharge status until the voltage of each of the batteries decreases, to the

overcharge hysteresis voltage (VCD) from the overcharge detection voltage (VCU).

2. Delay Circuit

The delay circuit rapidly charges the capacitor connected to the delay capacitor connection pin up to a specified

voltage when the voltage of one of the batteries exceeds the overcharge detection voltage (VCU). Then, the delay

circuit gradually discharges the capacitor at 100 nA and inverts the CO output when the voltage at the delay

capacitor connection pin goes below a specified level. Overcharge detection delay time (tCU) varies depending

upon the external capacitor.

Each delay time is calculated using the following equation.

Min. Typ. Max.

tCU[s] = Delay Coefficient (10,

15,

20)

× CICT [μF]

Because the delay capacitor is rapidly charged, the smaller the capacitance, the larger the difference between the

maximum voltage and the specified value of delay capacitor pin (ICT pin). This will cause a deviation between the

calculated delay time and the resultant delay time. Also, delay time is internally set in this IC to prevent the CO

output from inverting until the charge to delay capacitor pin is reached to the specified voltage.

If large

capacitance is used, output may be enabled without delay time because charge is disabled within the internal delay

time.

Please note that the maximum capacitance connected to the delay capacitor pin (ICT pin) is 1

μF.

S-8244 Datasheet(PDF) 13 Page - ABLIC Inc.