I've been watching this post with interest. My 2 cents:
Smarbaga, by your logic, fuses wouldn't exist. Your fuse for safety, failures and equipment protection. Faults happen, whether its a sliver of metal coming off a machine, or a component failure in the driver, fusing the DC supply side to the driver becomes at minimum equipment protection. i.e. your pocketbook. Throw that wrench so it creates a path between the high side driver and ground, bypasses the current sense circuitry and see what happens.
As to the diode/fuse logic. I had to sit back and think about it a little and completely agree with Mariss, if the fuse opens up and the diode isn't there, the potential damage is to the driver. I'd spend 50 cents to protect a $100 driver anyday.
Failure modes usually come from experience and familiarity with the technical merits of an application. I'd say Mariss and Gecko have a proven track record, I'd think long an hard before I questioned his logic. I know after reading this thread, thinking it through, I'm adding some diodes to my dc supply side fuses.
Mariss, you rule!!
O, BTW I'm a EE also.
Phil
Phil, Still too many interests, too many projects, and not enough time!!!!!!!!
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