Overvoltage Protection Circuit (6.85 V Threshold)

The NCP345 over-voltage protection circuit (OVP) protects sensitive electronic circuitry from over-voltage transients and power supply faults when used in conjunction with an external P-channel FET. The device is designed to sense an over-voltage condition and quickly disconnect the input voltage supply from the load before any damage can occur. The OVP consists of a precise voltage reference, a comparator with hysteresis, control logic, and a MOSFET gate driver. The OVP is designed on a robust BiCMOS process and is intended to withstand voltage transients up to 30 V.

The device is optimized for applications that have an external AC/DC adapter or car accessory charger to power the product and/or recharge the internal batteries. The nominal over-voltage threshold is 6.85 V so it is suitable for single cell Li-Ion applications as well as 3/4 cell NiCD/NiMH applications.