Hi, I'm using DRV8834 to drive a small stepper motor to open/close an air vent. If a user manually opens the vent, we think the backdrive may be causing a small number of field failures as the energy from the manually rotated motor gets fed back to the driver. The o-scope screenshot below shows one of the motor outputs, which appears to be clamping at ~5.8V. The clamping only appears to occur when the driver is in sleep mode. Our plan to fix this is to add some bulk capacitance to the motor rail, but I want to make sure we understand the problem.
Channel 1: Motor output
Channel 2: Motor power supply
Does it look like the internal MOSFET or some internal protection component is going into breakdown (does 5.8V clamping make sense in this context)?