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    Power Factor Correction

    D01.1 - Design of the Passive Clamp Snubber for the Flyback Converter Working As Automatic Power Factor Corrector

    Thursday, March 26, 2026
    12:00 PM - 1:45 PM CT
    Location: Poster 1
    If a flyback DC-DC converter is designed to always operate in Discontinuous Conduction Mode, then it can be used as a Resistor Emulator in an AC-DC conversion scheme, thus achieving a very simple, single-stage, Power Factor Corrector with galvanic isolation. However, the flyback transistor exhibits a significant voltage spike at the beginning of the turn-off due to the leakage inductance of the converter coupled-inductors. This spike must be limited using a clamp snubber. For low cost and low power applications, a passive dissipative clamp snubber is preferred over other possible options. The calculation of this snubber for the aforementioned case is clearly different from the classical DC-DC conversion case, mainly due to the continuous variation of the electrical quantities (transistor current and voltage) that takes place when the converter works as a Resistor Emulator. This calculation is addressed in this paper, even considering the influence of the transistor output capacitance. PSIM simulations and experimental results have validated the study developed in this digest.