Power circuit with overvoltage protection

摘要

Power circuitry is disclosed for protecting an electronic device during an overvoltage event. A voltage clamp is connected in parallel with a charge pump, wherein the voltage clamp limits an input voltage of the charge pump. A current limiting resistor couples a supply voltage to the voltage clamp and to the charge pump. A power transistor couples the supply voltage to a load, wherein a gate of the power transistor is controlled by an output of the charge pump during a power-on operation. When the supply voltage exceeds a threshold thereby activating the voltage clamp, the current limiting resistor limits a current flowing through the voltage clamp.

主权项

1. Power circuitry for protecting an electronic device during an overvoltage event, the power circuitry comprising:
a voltage clamp in parallel with a charge pump, wherein the voltage clamp limits an input voltage of the charge pump; a current limiting resistor coupling a supply voltage to the voltage clamp and to the charge pump; a power transistor configured to couple the supply voltage to a load, wherein
when the supply voltage exceeds a threshold thereby activating the voltage clamp, the current limiting resistor limits a current flowing through the voltage clamp; and control circuitry responsive to an output of the charge pump and configured to ramp a control voltage applied to a gate of the power transistor during a power-on operation.