Part Number: DRV8402
Gents,
The issue in a nutshell is on approximately 25% of our PCAs we’re seeing situations where the DRV8402 appears to act as though it’s using CBC (CycleByCyle Current Limiting) even though the current being delivered is nominal.
The telling part is the following scope shots where you can see the PWM_OUTPUT just shutdown while the PWM_input remains active and all of the other control inputs are stable.
C1: PWM_OUT
C2: PWM_IN
C3: DRV8402 FAULT_N
C4: Current of the attached load
Error while 48V in (C4) is stable:
ERROR while RESET_N is stable
I even thought to monitor the DRV8402 BST_B (C4) during the error but there were no clues there.
And lastly I scoped OTW_N (C4) which was also deasserted during the error.
Attaching schematic for reference.