Appendix D

Flyback Converter DCM Operation

The flyback converter in steady-state DCM operation is understood to go through three phases as shown in Figure D.1. In Phase I, the power switch turns on, and the primary winding current ramps up, starting from zero. It reaches a peak and stores energy in the magnetic core when the switch is commanded off. The output capacitor supports the load alone during this phase. In Phase II, the power switch turns off. The secondary winding kicks in, steering the stored energy to support the load and also replenish the output capacitor. When the secondary winding current ramps down to zero, Phase III commence until power switch is commanded on.

Figure D.1 Flyback Converter DCM Operation Sequence.

During Phase ...

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