Team,
Customer is facing the below system behavior on multiple boards.
Have you seen this behavior already? how can it be explained?
We use the DRV8412 (Dual H-bridge motor driver ) part as a double full bridge with overcurrent latching shutdown.
The oc-adjust resistance is set to 200k ohm which equals the lowest overcurrent threshold of 1.4A.
The current the load is drawing is smaller than that by a factor of 5. When be ramp u the PWM from 0% duty cycle to 50% the part goes into shutdown and the fault output will be set to active (OTW is inactive).
This happens even when no load is applied to the bridge just a filter.
According to the datasheet is this either undervoltage of GVDD, a bootstrap capacity which isn’t charged enough or a overcurrent shutdown.
The GVDD voltages as well as the charge in the bootstrap capacity were checked and showed no sign of undervoltage.
The currents were measured and were far below the overcurrent threshold of 1.4A (by a factor of more than 5).
But if the OC-adjust resistance is reduced to about 170k ohm, the part keeps working and isn’t going into shutdown.
Thanks in advance,
Anber
