Diagnosing H-bridge fault: IR2110 failure mode

Thread Starter

Robin66

Joined Jan 5, 2016
266
Hi. I'm hoping that someone with a lot more experience than me will recognise what I beleive is a failure mode of IR2110. I've built a motor driver that incorporates a standard boost converter, with 2 FETs driven by an IR2110. The boost converter stopped working properly while I was tuning its operation. I tested each discrete component one at a time and got it working again after switching out Cb. However the FET Q7 is now getting very hot after a couple of seconds operation. I put a probe across the source-gate and found the Q7 gate is switching on when Q8 is on. I've changed my code to not turn on Q7 at all ie. the FET should be operating as a diode. Is this a typical failure mode of IR2110?

Below is the schematic of the relevant circuit block, and the oscilloscope output with the probes on pin 1 and pin 3 of Q7. Q8 is on for 10us, but you can see that during this time there's ~5V across Q7's gate which decays away after Q8 is off

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Thread Starter

Robin66

Joined Jan 5, 2016
266
I bit the bullet this morning and extracted and replaced the IR2110. It's now working properly so it's most likely this was some internal failure mode

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