Patent ID: 8009404

Claim:
A power system comprising: a relay having a first terminal and a second terminal, the first terminal of the relay being electrically coupled to a secondary power source; a controller; a voltage regulator circuit having an input terminal and an output terminal, the input terminal of the voltage regulator circuit being directly electrically connected to the first terminal of the relay, the output terminal of the voltage regulator circuit being directly electrically connected to the second terminal of the relay, and the voltage regulator circuit being capable of switching, based on a control signal received from the controller, between providing a first output voltage and providing a second output voltage, wherein the provided output voltage is applied to the output terminal of the voltage regulator circuit; and a first diode and a second diode, each having a first terminal and a second terminal, the first terminal of the first diode being electrically coupled to a primary power source, the second terminal of the first diode being electrically coupled to a load, the first terminal of the second diode being electrically coupled to the second terminal of the relay and to the output terminal of the voltage regulator circuit, and the second terminal of the second diode being electrically coupled to the load; wherein the power system enables the load to be powered by the primary power source during normal operation, wherein an output voltage from the primary power source is lower than an output voltage from the secondary power source.