Part Number:DRV8303
Motor : 2*250W BLDC
Drive way: 3 Hall sensors and H-PWM-L-ON;
The issue is the motor running normally in case of light load, but when the load turns heavy, the motor sound big noise and the waveform is abnormal. Just like the pic below. The white rectangle indicates the question, the all gate of FET have been pulled down .However, It should be PWM.
what I have check:
1. Fault pin report the error , in line with the area of white rectangle; At the same time ,the OCTW pin kept high; then read the status reg which is 0xff (It is weird) .
2. The PWM input between MCU - > DRV8303 is OK;
3. I have check the PVDD\DVDD\AVDD\GVDD twice and did not found any unusual;(the cap near power pin follow the pdf)
4. the C- Vds waveform may have some mistake, but I didn't know clearly;
5. When the error occurd, the phase current was about 16A. The internal resistance of FET was about 3.8mohm, the max current allows 80A.
6. It also seems EN-GATE was OK;
7. I have 4 PCB boards(two layout ways), every board have the same phenomenon. The left driver is almost OK, and check the waveform could see some error. The right driver is serious.
8. I have disabled the OC detect. And set the OC_Adj is 31(2.4V);
