Patent ID: 8791679

Claim:
A power supply system, comprising: clamp circuitry configured to receive a bus power supply during a ramp up period of the bus power supply, the clamp circuitry is configured to generate a clamped power supply having a voltage that is based on a voltage of the bus power supply, the clamp circuitry is further configured to clamp an over voltage present on the bus power supply; charge pump circuitry configured to generate a voltage set point signal that is independent of the bus power supply, the voltage set point signal is indicative of a predetermined voltage level on the clamped power supply; and switch circuitry coupled between the bus power supply and the clamped power supply, the switch circuitry is configured to be controlled by the voltage set point signal, and further configured to generate a voltage level on the clamped power supply that is less than the voltage set point signal.