Hello,

I’m using a PDME2-S15-S24-S isolated power supply to power the IGBT side of the gate driver. The power supply outputs 24-ish V, and I’m using a TL431-Q1 adjustable shunt regulator to create a +16V and -8V rail.
When I measure the supply rails, I can confirm +16V and -8V are present. However, when I send a PWM signal to the gate driver, the output is ±12V instead of +16V/-8V. See attached images.

I have been able to dampen the overshoot by increasing the gate resistor but it is still there ...

This gate driver will be used for driving a beefy 1kV, 100A, SOT-227 IGBT. But it is not mounted yet and I am having problems!
The isolated supply circuit is as below:

and the driver circuit is as follows:


What could be causing this? Is it due to the gate driver, PCB effects, or something else in my setup?
Any insights or troubleshooting suggestions would be appreciated!

 

Hello,

Why is there an 8 volts zener accross the tl431?

Bertus

 

Welcome to AAC!
Your supply doesn't have outputs vddb and vssb which are needed as inputs to the driver IC.

 

Welcome to AAC!
Your supply doesn't have outputs vddb and vssb which are needed as inputs to the driver IC.

Thanks
It has, i just didnt include it as it similar to vdda and vssa

 

Hello,

Why is there an 8 volts zener accross the tl431?

Bertus

It is not populated .. i thought i might use either a 8v zener or a shunt regulator to get the 8v negative rail

 

How can we help you if you don't give us the complete picture of what you have?