Hi, I have a synchronous buck converter that is for charging a battery. see schematic below please. The simulation looks fine, but when I constructed the circuit, it did not work at all. I did all possible solutions, and it can't work . The picture below is what I saw from the oscilloscope.

Any idea? I even changed bootstrap cap many time, and the result is the same.


Channel 1 is high side VGS1
Channel 2 is low side VGS2

 

update: I got it working, I discovered my mistake . However, I notice big spikes in waveforms of VGS high side, VGS low side, the shared node between the two transistor voltage. You see the pictures below. The first one is VGS high side, second is VGS low side, the last one is the voltage of the shared node.

Does anyone know what is the reason of the big spikes seen on oscilloscope ? is it because of I have small dead time, or bigger ? or do I have to add a snubber circuit for the inductor ?

 

what is the reason of the big spikes seen on oscilloscope ?

Probe lead inductance?

 

Probe lead inductance?

It might be. Because I notice this is a common issue when using an oscilloscope