I am operating a flyback converter with 60V DC input and 6V DC output. The load connected across the output is 500mA. My mode of operation is DCM. If I have 4 valleys in the magnetizing ringing of Vds across the primary FET, it changes to 6 valleys at 100mA load. The switching frequency is unchanged in both the cases. Why does the number of valleys increases when the load is decreased?
1 Answer
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The duty cycle decreases to accommodate the lower load current. In DCM there is therefore a longer time not conducting thus more cycles of ringing.
