Rcs is optional for external low-side current sense, you will ignore. You will need an amplifier and analog sample MCU pin and low-side current sensing code from FOC. Values for Rcs based on 10A peak current are around 0.1 ohm. The manufacturer will most definitely ignore your email unless you buy from them 1000000 of those.
Yes, 1.4 ohm rdson resistance is high but then this is a 500V device for 20 cents, so compromises must be made.
The bad news is that they don’t seem to do much of anything
I’m running in 6 pwm mode and seeing good clean pwm signals on the input pins (H_1_A and L_1_A for example), but I’m not seeing any voltage on the motor side of the drivers.
I did find a couple of other issues. The zener diode which was supposed to turn on the 3.3 volt regulator didn’t work so I replaced that with a resistive voltage divider which seems to be working well.
I also noticed that datasheet for the driver board actually calls for 15V for VCCB instead of 12 volts so I soldered in an external power supply to get the right voltage there, but that didn’t have an impact.
I’m not quite sure what to try next. It seems like the operating conditions for the chip are being met at least as far as I can tell from the somewhat limited datasheet.
Here’s how I have the board set up. The modifications are to use a resistor divider instead of the zener diode to turn on the 3.3 volt regulator, and replacing the 12v regulator with an external power supply to see if the voltage there was limiting the board from coming on.
On the one hand I’m stoked that there isn’t an obvious issue for the sake of my ego, on the other hand it would be great if I did something silly that was easy to fix
I’m in Seattle, I’ve got a second un-modified board here that I’m happy to send to you if you want to poke at it in person.
