Patent ID: 7298601

Claim:
A protection circuit for a parallel power system comprising at least two parallel coupled multi-phase voltage regulator modules (VRMs), the protection circuit comprising: at least two separate isolation control circuits, each separate isolation control circuit being coupled to a different multi-phase voltage regulator module of the at least two multi-phase voltage regulator modules of the parallel power system, and each separate isolation control circuit comprising: a current sense circuit for sensing current polarity at an output of the respective multi-phase voltage regulator module; a controller coupled to the current sense circuit for automatically isolating the respective multi-phase voltage regulator module when an over-voltage condition exists at an output of the parallel power system and a positive current polarity is sensed at the output of the respective multi-phase voltage regulator module, wherein the at least two isolation control circuits of the protection circuit isolate only a multi-phase voltage regulator module having positive current outflow during the over-voltage condition, and another multi-phase voltage regulator module of the at least two multi-phase voltage regulator modules remains operational; and wherein each multi-phase voltage regulator module employs a synchronous rectifier at an output stage thereof, the synchronous rectifier ensuring that the another multi-phase voltage regulator module is sinking current prior to the isolation of the multi-phase voltage regulator module having positive current outflow during the over-voltage condition.