Patent ID: 7023187
Filing Date: 2006-04-04
Classification: H02M,Y02B,Y10S

Abstract:
1. A dual regulated DC voltage circuit comprising: an upstream buck mode DC-DC converter, coupled to receive a power supply voltage at a first input and providing a first regulated DC output voltage at a first output; and a downstream buck mode DC-DC converter, having a second input coupled in cascade with said first output of said upstream buck mode DC-DC converter, so that said downstream buck mode DC-DC converter receives said first regulated DC output voltage at said second input, and providing, at a second output, a second regulated DC output voltage that is a fraction of said first regulated DC output voltage, said downstream buck mode DC-DC converter including a window regulator that is operative, in response to receipt of a shutdown signal applied thereto, to shut down said downstream buck mode DC-DC converter independently of the operation of said upstream buck mode DC-DC converter providing said first regulated DC output voltage, and to maintain said second regulated DC output voltage within a predetermined voltage window of said first regulated DC output voltage during shutdown of said downstream buck mode DC-DC converter, so that no soft start delay is needed when said downstream buck mode DC-DC converter is turned back on.