Lucent Technologies Inc.

Tyco Electronics Power Systems, Inc.

Robert J Murphy, Jr

Mark E Jacobs

Richard W Farrington

Thomas G Wang

Ramanujam Ramabhadran

Shashank S Wekhande

A bias supply circuit and a method of operating a bias supply circuit for use with a switching power supply employing a main switch and an auxiliary switch and having an input voltage and a voltage across a clamp capacitor coupled to a transformer. In one embodiment, the bias supply circuit includes a bias supply winding associated with the transformer and configured to provide a first voltage dependent on at least one of the input voltage and the voltage across the clamp capacitor during a conduction period of the main switch or the auxiliary switch. Additionally, the bias supply circuit further includes a bias supply storage capacitor coupled to the bias supply winding and configured to provide a second voltage dependent on at least another of the input voltage and the voltage across the clamp capacitor during a conduction period of another of the main switch or the auxiliary switch. A sum of the first voltage and the second voltage provides a bias supply voltage.

Bias supply circuit and a switching power supply employing the same

A converter for enhancing power factor utilizes a line sense winding magnetically coupled to sense a voltage across a line inductor in the input of a high power factor power converter. This winding in the illustrative embodiment is typically a single turn. This winding provides a measurement of the derivative (with respect to time) of the line current, and a specially designed integrator connected to the winding provides the estimate of the line current. An integrator is operative to accurately estimate the current by using known properties of this current to prevent mismeasurement due to reconstructing the 'constant of integration' and any small biases in the integrator which normally cause errors.

Isolated input current sense means for high power factor rectifier

Growing community of inventors

Quinlan, TX, United States of America

Robert J Murphy, Jr