A soft-switched secondary-side post regulator

In a multiple output power supply with at least two relatively high power outputs, the first output is controlled by a soft-switched, phase-shifted resonant transition bridge (PSRB) in conventional feedback fashion. A second output is controlled by a secondary side post regulator that delays the leading edge of the PWM waveform to achieve regulation. By using a full-wave rectification arrangement with a controlled switch (a power FET) in series with each diode, there is negligible turn-on switching loss due to the transformer impedance and negligible turn off switching loss due to the reversal of the transformer voltage at the next half cycle. By obtaining the timing control signal from the proceeding falling edge of the PSRB switching cycle, the control of the second output is essentially decoupled from the control of the first output. High-frequency, multiple output power supplies based on the soft-switched PSRB are thus achievable.