hello everyone. I recently made a simple winding feedback flyback circuit based on UCC1800, with an input voltage of 36V and an output of 20V/0.1A. The schematic diagram of the circuit is as follows.
The circuit works normally, that is, when the full load is started, the Vds of the mos tube will have a large peak of more than 200 volts, as shown in the figer.
In the figure, green is the input voltage, blue and red are the output voltage, yellow is the ds voltage of the mos tube, the steady-state maximum value is about 100V, and at the moment of startup, the maximum peak is more than 200 volts.
If the input voltage starts slowly, there are not as big spikes, as shown in the figure below
I don't know why this happens? How can the circuit be improved? Can I just add a clamp circuit？
