Lucent Technologies Inc.

Van A Niemela

Wayne C Bowman

Allen Frank Rozman

A drive circuit for a converter and a method of driving a converter. The converter includes an inverter and a synchronous rectifier. The drive circuit includes: (1) a modulation circuit for generating a drive waveform for controlling the inverter and the synchronous rectifier employing a negative feedback loop, (2) a modification circuit, coupled to the modulation circuit, for sensing an operating condition of the converter and shifting a portion of the drive waveform as a function of the operating condition, the modification circuit thereby creating a variable drive waveform from the drive waveform without employing negative feedback and (3) a transmission circuit, coupled to the modification circuit, for applying the variable drive waveform to the converter, thereby allowing a variable nonconcurrent change in state of the inverter and the synchronous rectifier according to the function of the operating condition.

Power converter adaptively driven

A power converter having an input and output and a method of operating the power converter. In one embodiment, the power converter includes a power transformer having primary and secondary windings and a power switch coupled to the input and configured to impress an input voltage across the primary winding. The power converter further includes a hybridge synchronous rectifier coupled to the secondary winding and including first and second synchronous rectifier switches. The power converter still further includes a separate drive winding wound on the power transformer and coupled between the first and second synchronous rectifier switches. The separate drive winding is configured to alternately energize the first and second synchronous rectifier switches.

Self-synchronized drive circuit for a synchronous rectifier in a

A power converter with a self synchronized synchronous rectifier includes one or two drive windings to provide positive drive to the control electrodes of the controlled switches (FETs) of a self synchronized synchronous rectifier. The polarities of these windings are selected so that the switched devices are driven appropriately to rectify the periodic signal output of the secondary winding of the power transformer of the converter. In some arrangements one or two drive windings are included as extra windings in the power transformer and connected to provide the proper polarity drive signals. The turn ratios of the drive windings to the other windings are selected to provide the proper gate drive signal levels. In an alternative arrangement a separate drive transformer may be provided to supply the gate drive signals.

Growing community of inventors

Dallas, TX, United States of America

Van A Niemela