This 12 x PWM Hat have 12 x low side current sensors. The PWM driver have a separate PSU, DRV8313 is rated 60V and INA194 is rated -16 to 80V so they are not that easy to break giving the Hat a very decent protection level. A separate TVS and capacitor bank on motor PSU will in addition suppress unexpected spikes + there will be larger protection on the PSU itself. I feel quite comfortable with this design, but testing will show.
Connecting the current sensors low side is not the most optional for individual PWM signals, but it is ok for 3-Phase and Stepper Motors where I wanted them the most. The challenge with PWM is that current mostly leave high side out and get connected to ground, meaning we never pass a current sensor on low side. But – again – I do have a SW trick that I will test. Adding these low side was most straight forward due to DRV8313. But, I will actually evaluate if I should move them high side. This would actually simplify the PCB – I think.
I am looking forward to work with this one due to the advanced functionality you get with current sensors – and if anyone wonder the first project is actually my 3D printer. I will write a separate article about that later.