How to mitigate Drain Current Spikes at Switching Events

Hey,

I have simple torque controller, in which I have firstly used MOSFET (Ideal, Switching), and now shifted to N-channel MOSFET and parameterized it using datasheet. However, under the same setting and model, the drain current across the MOSFET (Ideal,Switching) is fine, but the drain current of parameterized MOSFET has huge current spikes at switching event.

I have tried adding anti-parallel diode as well, and also the gate driver has propogation delay of 50ns, but still the issue prevails. What could be the reason behind this and how could I mitigate such issue.

I am attaching hereby the screenshots of the drain current.

Thank you!

Answer 1

[Joel Van Sickel]

Hello Hassan,

thank you for sharing yoru model with the question. The issue you are running into is shoot through due to the dead time not being set up correctly. Because you are using 2 individual gate drivers, and both the up and down transition are BOTH 50 ns delayed, it means that the corresponding event on the complimentary device is also transitioning at the same time. Also, 50 ns is probably too short for dead time, especially with a 10 ohm gate resistance. I added a 100 ns delay just to the first propogation delay (logic 0-> logic 1) and this will reduce the magnitude of your curren spikes.

[Hassan Ali]

Thank You Joel for your timely response,

I have tried it, and it is working to some extent. I have tried different dead time to analyze the effects. Before the current spikes was at both turn-on and turn-off, but now only when switch is turned ion and conducting. I have attached the scope picture of VGS (high and low) and I think the deadtime between them is good. I have extended this deadtime up to 500ns between them but the results are still same. Could this indicate that there could be another issue within the conductive path.

Thank You!