A power supply for supplying power to a chipset includes a first voltage regulating circuit, which is configured to convert an applied power supply signal into a group of first supply voltages, and a second voltage regulating circuit, which is configured to convert the applied power supply signal into a group of second supply voltages. A control circuit is provided, which is configured to selectively enable the second voltage regulating circuit to generate the group of second supply voltages. An output discharge circuit is provided, which is configured to discharge an output stage of the first voltage regulating circuit in response to a transition of the first voltage regulating circuit from an active state to an inactive state. This transition of the first voltage regulating circuit from an active state to an inactive state can occur in response to a change in magnitude of the power supply signal.