Hello TI motor experts!
I was doing some testing on the DRV8824 evaluation board where the logic is supplied via the USB lead and the motors from a 24V PSU with its 0V connected to mains ground. I noticed that the current in the +24V motor supply line did not match that in the motor supply return. It seems that quite a lot of the motor return current is flowing back down the USB lead and presumably then goes through the PC mains ground connection back to the PSU. Isolating the PSU 0V from mains ground balances the current correctly.
If I design a motor driver board which is supplied with a logic 5V and a motor 24V from the same PSU (with a common, grounded 0V) should I keep the two 0V rails separate on the circuit board (two ground planes)? If I don't do that then I think that there will some motor current flowing back down my logic 0V to the power supply.
Any advice on this?
Many thanks.
Neil Warnock