A bridge rectifier circuit uses active switches for at least two of its four rectifying elements, and employs an active control circuit to control the state of the active switches. The active control circuit receives its input from the AC input to the bridge rectifier circuit, is powered by the DC output...http://www.google.ca/patents/US5510972?utm_source=gb-gplus-sharePatent US5510972 - Bridge rectifier circuit having active switches and an active control circuit
