Hi,
I am trying to build a capacitor charging circuit using a 24V battery. The supercapacitors are connected in series, and the capacitor bank needs to be charged up to 90V
I traced a circuit from a PCB, but I couldn’t complete the tracing as it is a 4-layer PCB, and I need to return it without causing any damage. The MOSFETs used in the circuit are rated at 60V, 75A.
I attempted to design a push-pull topology using 700V MOSFETs, but I encountered excessive drain-to-source voltage spikes, even after implementing a large RC snubber network.
Could someone help complete the circuit and explain its working? That would be extremely helpful.
Thank you!

 

Oh, it is the two-junction type of MOSFET!

What is the polarity of the spike? Do both transistors have this spike?

 

Oh, it is the two-junction type of MOSFET!

What is the polarity of the spike? Do both transistors have this spike?

The spike issue is in a different circuit that uses a push-pull topology, and yes, both MOSFETs in that topology experience the spike.

However, I want to confirm if the uploaded circuit is correctly traced from the PCB. I am unable to fully understand how it works, and I noticed that no snubber network was used in the PCB. If the circuit is correct, please explain its operation. If not, kindly correct it.

Thank you!

 

It appears to be a resonant half bridge topology, but it appears to be incorrectly drawn. Google it.

 

I have had problems with charging large numbers of capacitors in series. They do not charge up evenly.

I do not understand the capacitors on the left side. (capacitors in series again)
There is a 24V supply (battery) but you are using 1.5kV caps and 700 volt MOSFETs. I think you could use 100V or 50V parts on the left side.