Artesyn Technologies, Inc.

Texas Instruments Corporation

Texas Instruments (cork) Limited

Seamus Martin O'Driscoll

George Young

Andrew Bernard Keogh

Piotr Markowski

William James Long

Peter Michael Meaney

Plotr Markowski

Bernard Keogh

This invention relates to a control circuit for a buck power factor correction (PFC) stage. Buck PFC stages are commonly used in low cost, high efficiency power converters. These buck PFC stages are typically controlled using a very slow control loop with a crossover frequency of the order of 10 to 20 Hz. However, such a slow response is unsuitable for applications requiring overvoltage protection. The present invention overcomes the problems with the known control circuits for buck PFC stages by implementing a two stage control circuit having a fast outer loop control circuit and a slow inner loop control circuit. The fast outer loop control circuit is in operation during low load conditions and the slow inner loop control circuit is only active under load.

Control circuit for a buck power factor correction stage

A PWM modulator as might be used in a power converter, a drive signal will be generated on an output pin of an integrated circuit PWM controller device which is used to drive the output when the modulator is required to be on.

PWM controller with drive signal on current sensing pin

A power converter is disclosed. According to one embodiment, the power converter includes a first stage comprising a current source and a second stage comprising n output circuits for converting the current signal into n corresponding output voltages. Each of the n output circuits includes an output switch responsive to a corresponding ncontrol signal for regulating the corresponding noutput voltage. The second stage further comprises a controller for generating the n control signals. The controller includes, for each of the n output circuits, an error amplifier, a waveform generator, and a summing circuit. Each error amplifier is configured to generate an output signal based upon a comparison of the output voltage of the noutput circuit and a corresponding nreference voltage. Each waveform generator generates a waveform signal. The waveform signals for the n output circuits are characterized by a common amplitude and period, and the phases of the waveforms signals are spaced at predetermined intervals. For each of the n outputs, the corresponding summing circuit sums the output of the error amplifier and the waveform signal to generate an amplitude-shifted waveform signal. The controller further includes a comparator for outputting the n control signals to the output switches based upon a comparison of the relative amplitudes of the amplitude-shifted waveform signals.

Current-fed multiple-output power converter

A power converter is disclosed. According to one embodiment, the power converter includes a first stage including a current source for generating a current signal, and a second stage. The second stage includes n output circuits coupled to the current source for converting the current signal into n corresponding output voltages. Each of the n output circuits includes an output switch responsive to a corresponding ncontrol signal for regulating the corresponding noutput voltage. The second stage further includes a controller for generating the n control signals. The controller includes, for each of the n output circuits, an error amplifier, a waveform generator, and a summing circuit. Each error amplifier generates an output signal based upon a comparison of the output voltage of the noutput circuit and a corresponding nreference voltage. Each waveform generator generates a waveform signal. The waveform signals for the n output circuits are characterized by a common amplitude and period, and the phases of the waveforms signals are spaced at predetermined intervals. The summing circuit sums the output of the error amplifier and the waveform signal to generate an amplitude-shifted waveform signal. The controller further includes a comparator circuit for outputting the n control signals to the output switches based upon a comparison of the relative amplitudes of the amplitude-shifted waveform signals.

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Cloyne, Ireland

Seamus Martin O'Driscoll