I am working class-E DC-DC converter topology. I have the problem with the drain-source voltage which is not immediately start to rise the Vds voltage after the gate voltage zero. So, what are the values need to tune in order to get the ZVS (zero voltage switching). But, I can get it at another side which is Vds falling to zero. See, the attached Vds file.

 

I am working class-E DC-DC converter topology. I have the problem with the drain-source voltage which is not immediately start to rise the Vds voltage after the gate voltage zero. So, what are the values need to tune in order to get the ZVS (zero voltage switching). But, I can get it at another side which is Vds falling to zero. See, the attached Vds file.

Can't remember if the circuit has a name - but there is a transistor speed up circuit for driving the gate capacitance faster. A PNP with its emitter to the gate and collector to GND ensures rapid gate discharge when the drive signal goes low, the B/E junction must be bypassed by a diode so that the driver chip can push the gate high. A Shottky-barrier diode minimises drive loss, and its low PIV is protected because the transistor B/E will limit the reverse voltage to 0.7V.

 

Is this what you're thinking of?

 

Is this what you're thinking of?

What I described uses 1 transistor and 1 diode - but your way works too.

 

It's not really, "my way". I have never built this circuit, I just read about it and this is what I remembered when I saw your post. Feel free to modify as required.

 

It's not really, "my way". I have never built this circuit, I just read about it and this is what I remembered when I saw your post. Feel free to modify as required.

Some controller chips have Vcc around 30V, which is too high for the 18 - 20V Vgs limit for most power MOSFETs. When Vcc is not higher than that, the totem pole is better, but the transistor/diode speed up may be the only option if there is no suitable supply rail close at hand.

 

And add a pulldown resistor from gate to source.

ak