DRV8302 fault after interruped L1 connection

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Highcooley
Posts: 3
Joined: 17 Jun 2017, 17:37
Location: Aarau

DRV8302 fault after interruped L1 connection

Postby Highcooley » 17 Jun 2017, 17:47

Dear VESCers

I just got two brand new VESCs for my dual hub motor setup. After the first power up, they both worked fine. Then I cut a slot in the heat shrink tubing to solder the CAN bus connectors (all other connectors where mounted). I slipped with my cutter and cut the connecting wire of L1. Of course, I did not notice that at first. So I powered up the board several times, but no LEDs came on. After measuring, I figured out, that there was no 5V on the board. After close inspection, I found the broken wire, scratched off some of the lacquer and soldered it together. After that, the LEDs turned back on, but the red LED kept flashing three times with in short intervals. With BLDC tool, i checked for "fault" and got the DRV8302 error message. Does this mean, that my DRV chip is already toast or could there anything else be wrong to check? Thanks for your help!

Kind regards
Andy

Highcooley
Posts: 3
Joined: 17 Jun 2017, 17:37
Location: Aarau

Re: DRV8302 fault after interruped L1 connection

Postby Highcooley » 19 Jun 2017, 14:48

Meanwhile, I did some further investigation. The 5V and 3.3V rail seem to be ok, since I can measure the correct voltages on both rails. The DRV8302 chip gets pretty warm on the side of the buck converter, but no magic smoke has escaped so far. When the whole board is powered on, it draws 70-100mA at 30V.

I still don't know, what is causing the problem. My estimation is, that L1 shouldn't be a very critical component in the circuit. The fix of the part should work and I don't have any shorts there.

Can it be, that the interrupted L1 or a temporary short of the 5V rail to GND during my fiddling arround could have damaged the buck converter, so it gets warm and sends the error message, but still produces the correct voltage.

Thank you for your help!

Cheers,
Andy

parasole
Posts: 19
Joined: 29 Mar 2017, 05:18

Re: DRV8302 fault after interruped L1 connection

Postby parasole » 27 Jul 2017, 16:53

I don't think buck converter is sending any error message, according to data sheet it is fully isolated chip, basically DRV have two chips inside... The fact you have 5 V rail means converter is OK, and the problem is on driver side which actually send error message to CPU. I had my DRV burn off and it for sure was buck converter, so then I did try to provide a separate power supply for CPU side however by this action looks like I cooked out driver side too, so now waiting replacement chip...

rew
Posts: 905
Joined: 25 Mar 2016, 12:29
Location: Delft, Netherlands.

Re: DRV8302 fault after interruped L1 connection

Postby rew » 28 Jul 2017, 05:30

Using so much could be that your 12V line is shorted.


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