Hello all,
We have many devices on field that run BLDC motors over 36 V Li-Ion Battery (42 V max.). The same bus (MAIN_SUPP in the Sch below) also powers our main board. We have lost 5 V supply on a significant number of devices on the field. When we analyze the device logs we observe peak voltages up to 58 V and DC level increse up to 47 V for about 15 seconds. Although these levels are acceptable for the chip and the design, we observed that converter ICs blow up from the same point.
We put so much effort the recreate this on a controlled environment but haven't been able to damage the chips this way. Can the location of the cap-off give us some idea about the problem we're having? Is this caused by overvoltage, surge, temperature, or something else? What we need is to find the exact reason to take preventive action on the boards that are already in use, as well as to avoid it in new designs.
Best regards,
Gunay Turan
