DRV8302 Magic Smoke

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

Re: DRV8302 Magic Smoke

Postby rew » 22 Apr 2016, 04:46

Caps at 50v: no problem. You do need low ESR ones, all brands make cheaper versions that have higher ESR.

Some Aliexpress sellers may relabel normal capacitors as the low ESR version, or rebrand by changing the print........

theBob
Posts: 7
Joined: 22 Feb 2016, 03:13
Location: Australia

Re: DRV8302 Magic Smoke

Postby theBob » 16 May 2016, 11:49

I think I've found the culprit, the cap C33 is completely burnt out also on my VESC. Does anyone know what C33 is for? Might give an indication as to the cause..

Florian
Posts: 4
Joined: 01 May 2016, 17:46
Location: Munich, Germany

Re: DRV8302 Magic Smoke

Postby Florian » 16 May 2016, 13:50

According to the schematic in version 4.12 C33 is the output capacitor of the 5V switching regulator in the DRV8302. This is the power supply for the microprocessor. Look at the images in this thread to see the relevant part of the schematic. (http://vedder.se/forums/viewtopic.php?f=7&t=195#p1171)

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

Re: DRV8302 Magic Smoke

Postby rew » 17 May 2016, 19:40

If that is the case... Double check that your DRV8302 has a proper ground connection. (The big tab in the middle of the chip needs to be soldered to ground!).

notger
Posts: 23
Joined: 16 May 2016, 17:12
Location: Austria

Re: DRV8302 Magic Smoke

Postby notger » 11 Jun 2016, 20:03

Hi,

these replys here are not very old. ouch.
So i get a bit wooried, cause i did not read about his problem enertion has/had.

I just ordered a while ago, 4 VESCS with friends together.
The last message, from enertion was that they will get deivered with the next"batch" middle of July.
So, i guess/hope this will be a really new batch with problems solved.

does anyone know if enertion took this problem serious, and did make changes, or if this could also be a problem of the VESC itself?
i guess ill get a 4.7, if this is the most actual version ?!

where there VESC changes concerning this "Magic Smoke"-problem in the latest updates 4.6,4.5,...?

thanks in advance, i/we just want to be sure that will will not send the vescs to heaven even with right setup, but without rational understanding of Mistakes we might have done to kill it.

Thanks

Not-ger-not

arvidb
Posts: 206
Joined: 26 Dec 2015, 14:38
Location: Sweden, Stockholm

Re: DRV8302 Magic Smoke

Postby arvidb » 13 Jun 2016, 11:45

notger, you can check the git commit log to see which HW version is the most current.

But if this problem has to do with bad capacitors, or bad soldering of capacitors, as indicated earlier in the thread, then it's not possible to fix the problem by changing the VESC itself.

Have you asked Enertion about this problem and if they've done anything to fix it (better capacitors, better soldering technique)? Enertion states on their homepage: "NEW CAPACITOR BOARD INCLUDED", so maybe they've at least taken care of the soldering problem?

RSR
Posts: 10
Joined: 08 Mar 2016, 16:58

Re: DRV8302 Magic Smoke

Postby RSR » 06 Aug 2016, 11:55

Magic smoke escaped from DRV8302 when I was testing FOC and 12S on a VESC 4.12. Temperature of board was low when this happened.
I suspect FOC and 12S is a bad combination for this VESC -- it seems to work better with in BLDC mode.

The PCB appears to be toasted; the track to PVDD1 (corner leg of DRV8302) evaporated and the next 3 tracks are loose.
It looks like the body pad was not properly soldered -- too little solder and/or too little heat. Can this be the cause of failure?

What do you think caused this?
Is it worth to try repair (replace DRV) ?

VESC_desolder2.JPG
VESC_desolder2.JPG (821 KiB) Viewed 1704 times
DRV8302.JPG
DRV8302.JPG (345.81 KiB) Viewed 1704 times

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

Re: DRV8302 Magic Smoke

Postby rew » 06 Aug 2016, 19:53

IIRC, one end of the DRV does current-sense-resistor-voltage amplification, and the other the DCDC conversion.
The end with the blown tracks seems to be the end that does the current-sense amplification. That's odd. I'm not convinced that this all happened when the chip blew up, as opposed to when it was wrenched from the board....

IMHO the 6 patches of solder beneath the chip looks like sufficient to solder it down.

RSR
Posts: 10
Joined: 08 Mar 2016, 16:58

Re: DRV8302 Magic Smoke

Postby RSR » 07 Aug 2016, 08:59

The other side of my DRV8302 looks very similar to the pictures from vitormhenrique and theBob showing a burned spot and overheated trace towards PVDD1 pin. It was discussed, but not concluded, if capacitors was the cause. Capacitors on my board look OK (3x Nichicon 560uF 63V and a big ceramic without text). PVDD1 powers the gate drivers and the current sensor amplification, maybe the gate driver becomes overloaded during FOC?

Yes, the bending of loose tracks happened when removing the DRV-chip. Only the chip and the PVDD1 track were blown before I removed the chip, but the board was slightly toasted so that tracks close to PVDD1 were loose.

The chip came off quick and easy when heated with air, and I can see very little solder left on the body pad. I am not sure if the solder on body pad (ground) actually fused to the chip or if it was just flattened. Maybe one of you who have replaced DRV-chips before can take a look at this and say if the solder left on the body pad looks OK/normal.

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

Re: DRV8302 Magic Smoke

Postby rew » 07 Aug 2016, 11:52

The PVDD1 pin powers a (wimpy: 30mA max) linear 12V regulator. The only way I can think of that would blow the track there is that an enormous current flowed through the DRV chip. That would mostly mean that the whole chips is fused to one lump of silicon.

Yes, FOC on VESC exceeds that 30mA limit....

Do you have an exact type number for those nichicon caps? I'm looking for caps myself.


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