ZVS driver oscillating weirdly

Thread Starter


Joined Apr 23, 2021
I've been trying to make a ZVS driver which feeds into the primary coil of a center-tapped transformer.
I've attached the LTspice file down below.

Below is the waveform I got when I attached the outputs of the ZVS driver to an LC tank. One thing that bothered me however, was the fact that the oscillating frequency did not tally up with the its calculated version. I was using a 100uH inductor and a 4.7nF capacitor to create the LC tank, thus the oscillating frequency should be 232kHz, but as you can see that is not the case.
So i started to suspect that it could have just been some random noise, but I carried on anyway.


Next, I soldered the rest of the board, complete with a homemade center tapped transformer, following this electroBOOM video.

Afterwards, I got the following waveform

The waveform with a frequency around 50Hz seems to be interference from the power supply


But it still seems like the actual frequency, which is ~40kHz deviates a lot from the calculated frequency, which is ~300kHz+. Additionally, the actual waveform still oscillates between 6.7V and 5.7V only

I suspect it might have something to do with the actual components I picked out. Unlike the simulation i used IRFP260N MOSFETs and UF4001. One thing that stood out to me was the 1V forward voltage of the Schottky diodes, but this should not affect the MOSFETs since the minimum gate threshold voltage is 2V.

What should I do?



Joined Jan 29, 2010
hi ican,
Downloaded your file, will give it a run.

Please post your freq calculations.
I make ~56kHz.

BTW: added a light load

The circuit you posted today is the same we used sometime ago, .???


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