Patent ID: 6873191

Claim:
An apparatus for generating a regulated direct current (DC) output voltage at an output node to which a powered device is coupled, comprising: a DC—DC converter coupled to a supply voltage, and being operative to generate a regulated output voltage derived from said supply voltage, said DC—DC converter having a pulse width modulation (PWM) generator which generates a PWM switching signal that switchably controls operation of a switching circuit containing first and second electronic power switching devices coupled between respective first and second power supply terminals, a common node thereof being coupled through an inductor element to said output node; and an overvoltage sense circuit which, monitors the voltage at said common node and is operative, in response to the voltage at said common node reaching a value during initial power up of said apparatus, indicative of the onset of an over-voltage condition at said common node, associated with a short circuit through said first electronic power switching device between said first power supply terminal and said common node, to turn on said second electronic power switching device, so as to provide a by-pass current flow path from said common node to said second power supply terminal, and thereby prevent an over-voltage from being coupled to said output node and applied thereby to said powered device.