bq2944L9

bq29440, bq2944L0 bq29441, bq29442, bq29443, bq29449, bq2944L9 www.ti.com SLUSA15C – JUNE 2010 – REVISED NOVEMBER 2010 Voltage Protection for 2-Series, 3-Series, or 4-Series Cell Li-Ion Batteries (Second-Level Protection) Check for Samples: bq29440, bq2944L0, bq29441, bq29442, bq29443, bq29449, bq2944L9 FEATURES 1 2-Series, 3-Series, or 4-Series Cell Secondary Protection External Capacitor-Controlled Delay Timer Low Power Consumption ICC < 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 speci...