TB6612 Caught on fire!

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hellraiser94
 
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TB6612 Caught on fire!

Post by hellraiser94 »

Hello, I was looking for help on why my DC motor controller (https://learn.adafruit.com/adafruit-tb6 ... t/overview) just caught on fire. I had it connected to a 12VDC power supply, the motor it was connected to was not being operated, and the arduino it was connected to was unplugged. Essentially the only thing plugged in still was the power supply. Does this break some golden rule of circuits? I assumed that since it was rated for 13VDC it would be able to handle 12VDC with no problem. Especially when nothing was being operated.

Edit: Just had a thought, since the Arduino was not plugged in, would this be an issue with the chip not being grounded? Everything would have been grounded back to the board but the board was unplugged. Just looking for insight so when I purchase my next one I don't make it melt too!

The attached photo shows the wiring, poorly, but it's the best I could get. The power supply was attached to wires soldered into the Vmotor holes.
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adafruit_support_bill
 
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Re: TB6612 Caught on fire!

Post by adafruit_support_bill »

Please post some photos showing your soldering and connections to the board. Also post some electrical specs for the motor you are using.

If the board inputs are not connected, the inputs will be 'floating' so the state of the outputs is unpredictable. It is possible for this to create a "shoot through" condition where the device will short itself out.

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hellraiser94
 
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Re: TB6612 Caught on fire!

Post by hellraiser94 »

Thank you for the reply. I don't have access to the board until tomorrow, but I had the soldering done by an electrical engineering technician at my place of work. The solders looked very good as far as I could tell, there were no touching connections which was to be expected since this person solders as a job. The motor is this motor (https://www.adafruit.com/products/1150). As far as I can tell the only issue seems like it may have been that everything was unplugged and thus the power supply couldn't ground. I'm unsure if that would cause the issue though.

Edit: Could this shoot through be prevented if I just grounded the motor control B ports? As shown in the picture I don't have anything connected to them.

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adafruit_support_bill
 
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Re: TB6612 Caught on fire!

Post by adafruit_support_bill »

Actually, looking at the data sheet, the TB6612 bridge circuit should not allow shoot-through, so I don't think that was the case. That pump motor should not be a problem either. But just to be sure, try running it directly from your power supply to make sure there is no internal short in the motor.

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hellraiser94
 
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Re: TB6612 Caught on fire!

Post by hellraiser94 »

The motor still works without a problem, power supply also seems to be undamaged.

Attached is the requested photo of the connections. I'm going to place an order for another board now, hopefully the answer to this conundrum is simply that I had some bad luck and received a defective board.
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