Patent Number: 7,787,222

Title: Over-voltage protection for voltage regulator modules of a parallel power system

Abstract: A protection circuit for a parallel power system having at least two parallel coupled voltage regulators is disclosed. The protection circuit includes at least two isolation control circuits, each control circuit being coupled to a respective voltage regulator. Each isolation control circuit includes a current sense circuit for sensing current polarity at an output of the respective voltage regulator, and a controller for automatically isolating the respective voltage regulator 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 voltage regulator. The at least two isolation control circuits isolate only a voltage regulator having positive current outflow during the over-voltage condition. In one embodiment, each isolation control circuit further includes an over-voltage detection circuit for detecting when the over-voltage condition exists at the output of the parallel power system.

Inventors: Covi; Kevin R. (Glenford, NY), Harrington; Raymond J. (Staatsburg, NY), Makowicki; Robert P. (Staatsburg, NY), Shevach; Steven G. (Hurley, NY), Soreson; Dale F. (Ruby, NY), Tucker; Brain C. (Hyde Park, NY)

Assignee: International Business Machines Corporation

International Classification: H02H 3/20 (20060101)

Expiration Date: 8/31/12018