Hello,
I'm trying to make work my custom board featuring a DRV8301. As long as PVDD remains below 28V, the motor turns well, but as soon as I increased the voltage beyond, GVDD start becoming very noisy (a square wave at switching frequency, with low dutycycle, is visible on the GVDD and BST_x pins), and if I continue to increase PVDD voltage, a little more (let's say 28.3V), the DRV8301 triggers a fault (0x600 in SR1), and stop switching.
Capacitor (X7R or X5R) are about the same values and voltage rating than those of the DRV8301-HC2 kit, and below 28V, waveforms appear to be clean on all pin (a small ripple is present on PVDD though but I wonder less than 200mV pp should be acceptable ?), even if current measurement is noisy (1mOhm shunt at no load (10W, board is designed to run up to 55V, 40A continuous).
What is really strange is the threshold which does not change with switching frequency or when increasing GVDD cap.
An other important thing : when motor is disconnected, the problem does not occur (up to 30V, maximum voltage of the power supply I'm using)
Any idea ?
Thank you for any suggestion !