After stable Voltage output my MOSFET drain and high side of half bridge is in bursting mode

[Vikas ji]

Hello everyone I am new here.
I have problem in half bridge SMPS in which my output voltage is 23v stable which I set through optocoupler feedback. But after output voltage stable when input given around 120 v AC the drain and High side gate goes in bursting mode and not making own smooth.

I just want to know in half bridge SMPS is normal or it is a problem.

Dummy load is 100k and pwm frequency 50khz,
Deadtime 900ns,
The drain waveform and I have is

 

[betwixt]

The 1K resistor at the top of the schematic probably should be across gate and source pins, not gate and ground. With high voltage on the drain you are probably exceeding the drain-gate limit.

Brian.

 

[Vikas ji]

Thanks for your reply.
It is only test purpose before I connect MOSFET with it. It is used to discharge high side so I can get pulse in CRO.
Then after that everything ok on this predriver module I removed this 1k resistor and connect the MOSFET and so on circuit.
SMPS circuit working fine .
But when I check the drain point it shows this type of waveform like sine wave not own it is ok or not

 

[Vikas ji]

Reference circuit is this which I using

 

[FvM]

The converter is running with effectively no load, resulting in low duty cycle. Without knowing the transformer properties, it's hard to say if the waveforms are o.k.