Hi,
I'm having a problem with an isolated half bridge driver circuit where the gate driver keeps failing.

I'm trying to use two "Si8261BBC-C-IP" isolated gate driver ICs to isolate the MCU from the MOSFETs, but it keeps failing after less than 1 minute. As soon as I replace the component with a "FOD3180TV", the circuit works for more than one hour.

At this stage I'm using a resistor as a load in my test circuit which is running at about 50-kHz and a 40 % duty cycle.

I would really like to have someone just look at my circuit diagram and make a suggestion as to what might be wrong or what I might improve on. The problem is that the gate driver keeps failing and I just simply cannot understand why and what is wrong. The output of the circuit (as measured on an oscilloscope) seems to be a perfect square wave.

Any advice would be greatly appreciated.
Kind Regards

 

Hi,
I'm having a problem with an isolated half bridge driver circuit where the gate driver keeps failing.

I'm trying to use two "Si8261BBC-C-IP" isolated gate driver ICs to isolate the MCU from the MOSFETs, but it keeps failing after less than 1 minute. As soon as I replace the component with a "FOD3180TV", the circuit works for more than one hour.

At this stage I'm using a resistor as a load in my test circuit which is running at about 50-kHz and a 40 % duty cycle.

I would really like to have someone just look at my circuit diagram and make a suggestion as to what might be wrong or what I might improve on. The problem is that the gate driver keeps failing and I just simply cannot understand why and what is wrong. The output of the circuit (as measured on an oscilloscope) seems to be a perfect square wave.

Any advice would be greatly appreciated.
Kind Regards

Looks like it should work to me. Is it always the top one that blows?

 

Hi, thanks for the reply.

No, sometimes the low side one also fails.

 

I have replied on the ETO site.

 

Hi, thanks for the reply.

No, sometimes the low side one also fails.

One of the differences between the 2 ics is peak drive current - .4 amps for the one that blows. It's likely you are violating this spec. You could try increasing the gate resistors to say 47 ohms.