1FEATURES

• 2-Series, 3-Series, or 4-Series Cell Secondary

Protection

• External Capacitor-Controlled Delay Timer

• Low Power Consumption I CC < 2 μA Typical

[VCELL(ALL) < VPROTECT]

• High-Accuracy Overvoltage Protection: ±25

mV with TA = 0°C to 60°C

• Fixed Overvoltage Protection Thresholds:

4.30 V, 4.35 V, 4.40 V, 4.45 V, 4.50 V

• Small 8L QFN Package

APPLICATIONS

• Second-Level Protection in Li-Ion Battery

Packs

– Notebook Computers

– Power Tools

– Portable Equipment and Instrumentation

DESCRIPTION

The bq2944x is a secondary overvoltage protection IC for 2-series, 3-series, or 4-series cell Li-Ion battery packs

that incorporates a high-accuracy precision overvoltage detection circuit.

FUNCTION

The voltage of each cell in a battery pack is compared to an internal reference voltage. If any cells reach an

overvoltage condition, the bq2944x device starts a timer that provides a delay proportional to the capacitance on

the CD pin. Upon expiration of the internal timer, the OUT pin changes from a low state to a high state. An

optional latch configuration is available that holds the OUT pin in a high state indefinitely after an overvoltage

condition has satisfied the specified delay timer period. The latch is released when the CD pin is shorted to GND.