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.