Patent ID: 7064534

Claim:
A system, comprising: a first voltage regulator having a supply input coupled to a common unregulated supply voltage, an enable input and a first supply output, the first voltage regulator selectively providing at the first supply output up to a first predetermined current level at a regulated voltage based upon the common unregulated supply voltage; compare circuitry having an input coupled to a first unregulated supply voltage and an output having a value indicative of whether the first unregulated supply voltage is greater than a predetermined voltage level; a second voltage regulator having a supply input coupled to the common unregulated supply voltage, an enable input responsive to the compare circuitry output and a second supply output, the second voltage regulator selectively providing at the second supply output thereof up to a second predetermined current level at a regulated voltage based upon the common unregulated supply voltage, the first supply output of the first voltage regulator being coupled to the second supply output of the second voltage regulator; and switching circuitry operable responsive to the output of the compare circuitry for applying either the first unregulated supply voltage or a second unregulated supply voltage as the common unregulated supply voltage.