Other Parts Discussed in Thread: TIDA-00620, DRV8871, DRV8870, DRV8872
Hello,
I am working on a Brushed motor driver based on a DRV8701with CSD18540Q5BT mosfets to Drive a 24V 50W BDC Gearmotor. For reference I have purchased a DRV8701-EVM eval board, and I am referring to TIDA-00620, DRV8701 & DRV8701-EVM datasheet.
This is my first attempt at designing a motor driver from scratch, I have always used L6203 designs in the past. I am pretty happy with the overall design, but I have a couple of questions regarding protecting the mosfets during sudden braking/direction change etc. Using the L6203, I would place a RC snubber across the motor output, and a TVS, which limited spikes across the VM rail to a minimal value.
I have noticed that there are no external freewheeling diodes across the mosfets in any of the designs. Is this because the internal mosfet diode is considered to be sufficient? Should I allow space on my pcb for external diodes? Also, is there any other protection I should allow for on the Mosfet bridge output to protect against sudden motor stop or direction change?
Kind Regards
John