I designed a driver board using the TB6560 chip which just drives some coils, not a motor. I've made about 200 of these boards over the last two years and there have been no failures. Over the last few weeks I've experienced about 50% failure rate. I thought maybe it was a bad batch of chips so ordered the chips from another supplier but still experiencing a high failure rate. The chip is susceptible to static and back emf which I suspect could be an issue but don't understand why I'm just now having problems. The chip can fail immediately or within a few hours. I've gone back and read the datasheet and searched for sample circuits to see if I left out some termination or maybe flyback diodes on the outputs but nothing is telling what may be wrong. The chip is rated at 3.5 amps but I have it limited to 2a for 10 seconds then drops to 800 ma for about 4 minutes. It doesn't run hot.
I've attached the circuit if someone could look at it see what I may be doing wrong I really appreciate it. Or suggest a reason why I'm just now experiencing issues.
Thanks.
I've attached the circuit if someone could look at it see what I may be doing wrong I really appreciate it. Or suggest a reason why I'm just now experiencing issues.
Thanks.
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