DRV8350: drv8350 not work and the Vgls and GLX is short

Hello user6292140;

Thanks for posting on the Motor Drivers Forum! Let me give you a full response tomorrow, 9/10/20 CDT.

My first impressions lean towards layout. Can you confirm the locations of the internal short by taking a Digital Multi-meter and using the impedance test between the two pins you think are internally shorted?

Gate Drive faults on Low-side A means that the GLA would be shorted to GND, or VGLS. Where GDUV means that VGLS or VCP is shorted to GND, VDRAIN, or VM.

The reason I think that layout is the problem relates to what you've told me so far. I am assuming you:

• Kept the schematic the same between Motor 1, 2, and 3 (as you've mentioned)
• Used the same group of devices from the same tube or reel
• Used very similar motors for 1, 2, and 3 that require similar voltage and power

The only differences are:

• layout between Motors 1, 2, and 3
  • Layout of Motor 1 does look much better. More area devoted to phase and FET nodes and the gate paths look much more symmetrical 
• Both DRV8350's for Motor 2, and 3 were damaged before driving the motor, and the DRV8350 was not
  • This is unlikely, but can test this by desoldering the DRV8350 used for motor 1, soldering it in place of motor 2 or motor 3, and repeating the experiment. If the motor runs in motor 2 or 3, then the devices were at fault
• Something in the sensing path for Motor 2 and 3 were damaged or different which then contributed to incorrect commutation  

• This is also unlikely as we have plenty of protection features that will attempt to stop incorrect commutation

Best,

-Cole

hello Cole,

        thank you for your valuable suggestion .

        The short location is pin 31 VGLS and pin15 GLC of all damaged drv8350.

         Yes,  I also think the gate path of MT1 is better.But because of the sides of board ,I have no space  to make its area bigger.So

how I can improve the 2 and 3  to make it perform like 1?

Thank you 

Shengzhong

hello Cole :

      we have tried  to exchange the chip  boto 1 ,2 and 3. The chip 1  moved to phase 2 or 3,the motor 2 and 3 all wili not work.

       AND I  found that there will be -3V (some time bigger) in SLC  occasionally. i thinks there must be some problem in the layout which caused this problem .Can you leave your email address and I send my pcb project to you .And then we can discuss way to solve it.

best 

shengzhong