Part Number: LM5122
Hello,
I've got some unusual problem related with start up event (no load) of 4 stage boost converter. It is based on GaN switches instead of standard MOSFETs. I started to run this converter stage by stage. It meant I ran 1st stage only and it works quite well. When I soldered additional 2nd stage something is wrong and a few components fails (especially LS GaN of the second stage). Generally it seems as shoothrough on the second stage and because the LS is weaker than HS it dies first and in the most spectacular way. I've checked driving waveforms for LS and HS when only one channel was soldered and they seems inside range specified for GaNs. The main problem is how to debug this problem especially it happens at start up. Do you have any ideas what could be wrong? I wonder about MODE pin which now is tied to VCC so FPWM mode is applied but I'm not convinced that's the real issue and I don't want to lose too many switches.
BR
Dariusz Jewula
