UCC21520: UCC21520AQDWRQ1

Hi Shritesh,

Could you provide a schematic of the gate driver and waveforms showing the operation of the gate driver as well as the spikes that you are seeing? 

Regards,
Krystian

Gate Driver Circuit.pdf

Hi Krystian,

Thanks a lot for your response.

I have attached the schematic of gate driver circuit as pdf file. 

I have also added two images:-

Image #1 {single yellow waveform} PWM input waveform when power board in not connected.

Image #2 {Transformer primary voltage (blue) and PWM pulses (pink)} PWM waveform when power board is connected. In second waveform you can see waveform across transformer also. Please note that, I am observing spike during crossover in transformer input. This spike increases when DC link voltage is raised.

Thanks,

Shritesh

Hi, 

We are looking into your issue, and will get back with you shortly. 

Best regards,

Don

Thanks a lot Krystian for identifying the issue. Above image shows representative layout of my board. As you correctly identified there is a possibility of coupling between transformer and gate driver traces as they are very close.

What are your suggestions to avoid this kind of coupling in future?

Thanks,

Shritesh

Hi Shritesh,

There are a few improvements like minimizing trace length, making decoupling capacitors close to the gate driver, and possibly moving the gate driver further away from the transformer. Based on your picture, is the gatedriver on a separate pcb that plugs into the vertically mounted plugs?

Hi Krystian,

As you correctly identified, gate driver is on separate board which can be plugged into power board using board to board connector.

Thanks a lot for your suggestions. This will be helpful for my next design.

Thanks,

Shritesh

Thanks, Shritesh, for confirming.

Best regards,

Don