Maybe it's a failure of my imagination, but I just can't imagine a scenario where anything I can do with the input pins can cause the FET driver to self destruct. The bridge, sure, possibly cascading back to the driver. But the last failure was driver only, the FETs survived. I'm also choking on the idea that six failures on two different designs have _all_ been connected to the same processor pins. One says "hardware" the other says "software". I am wondering about this though - what happens with the bootstrap generator when the the current sense resistor goes? So the low side can no longer pull Vs near ground and I'd think the bootstrap can no longer charge... yes? So Vb starts falling closer to Vs and at some point either the output stage in the high-side FET driver or the high-side FET in the bridge winds up in the linear region... The datasheet shows this part having UVLO to prevent this, but... Also, this part is rated for voltage swings on Vs to _negative_ 9.8v. Not that we couldn't be exceeding that... As to another make/model FET driver, that's on the agenda, but won't be here till next week. But I'd appreciate recommendations if anybody has a favorite part. -Denny On Fri, Nov 29, 2013 at 9:34 AM, wrote: > > Much of the hardware designs are cut and paste of each other. The power > is > > coming from a 28V Li-Ion battery, the regulators are the same National/= TI > > LM2675 parts, the FET drivers are the same Fairchild FAN7382. The three > > phase unit has massive TO-220 FETs and the other has some smaller SOIC = 8 > > parts. > > I haven't looked at that driver chip, but wonder of you have some strange > condition causing it to have overlap in its output (as distinct from > overlap in your power transistors). > > Have you tried patching in some other manufacturers driver chip on your > test bed (dead bug if need be)? Maybe get a sample from Microchip to rule > that possibility out? > -- > Scanned by iCritical. > > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .