Patent ID: 7948293

Claim:
A method of generating a power supply voltage, the method comprising: receiving a control signal that indicates which of a first voltage source and a second voltage source provides the power supply voltage; in response to the control signal indicating the second voltage source provides the power supply voltage: deactivating the first voltage source from providing the power supply voltage, pre-biasing the first voltage source with a voltage pre-bias to facilitate each transition from the second voltage source to the first voltage source, and activating the second voltage source to provide the power supply voltage; and in response to the control signal indicating the first voltage source provides the power supply voltage: deactivating the second voltage source from providing the power supply voltage, generating a bias voltage that amplifies a difference between a reference voltage and the power supply voltage, wherein at the transition the bias voltage ramps from the voltage pre-bias, and activating the first voltage source to provide the power supply voltage, including applying the voltage pre-bias to a voltage driver of the first voltage source to maintain the power supply voltage during the transition.