The bq2947 family is an overvoltage monitor and protector for Li-Ion battery pack systems. Each cell is monitored independently for an overvoltage condition.
In the bq2947 device, an external delay timer is initiated upon detection of an overvoltage condition on any cell. Upon expiration of the delay timer, the output is triggered into its active state (either high or low, depending on the configuration). The external delay timer feature also includes the ability to detect an open or shorted delay capacitor on the CD pin, which will similarly trigger the output driver in an overvoltage condition.
For quicker production-line testing, the bq2947 device provides a Customer Test Mode with reduced delay time.
2-, 3-, and 4-Series Cell Overvoltage Protection
External Capacitor-Programmed Delay Timer
Factory Programmed OVP Threshold (Threshold Range 3.85 V to 4.6 V)
Output Options: Active High or Open Drain Active Low
High-Accuracy Overvoltage Protection: ±10 mV
Low Power Consumption ICC ≈ 1 µA (VCELL(ALL) < VPROTECT)