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Note: I have added a schematic since originally posting. Also here is the data sheet for the chip and here is a link to an overview of the actual board that I am using.

I am working on a project that uses an adafruit pro trinket 5v/16mhz to control a TMC2208 silent step stick in order to drive a small nema23 gear motor with a relatively light load. I know that the stepper driver is a bit underrated for a nema 23 but in this application, it should be fine.

I have used setups like this before with no problems but I am finding that if the 24vdc that I am using to drive the stepper is connected to the VM/GND pins, the driver burns up immediately. This is with/without the the 5v logic power connected and with/without the stepper connected. I have burned through a number of these and I seem to have some sort of fundamental lack of understanding of some aspect of this setup although I have used setups like this without issue. In this case, I used a few different 24v power supplies which were all rated at 5amps, do I need to use a lower amp power supply? I have check the polarity and I have also checked to make sure that I am not sending 24v to the logic pins, just the motor power pins.

Basically, under what circumstances can I connect voltage to the motor power pins of these stepper drivers without causing them to burn up. I can't get any more TMC2208 locally so I will use something like the DRV8825 but I'm having the same problem. I feel like I am going crazy and I need to finish this project for tomorrow, any help would be appreciated. Thanks

schematic

simulate this circuit – Schematic created using CircuitLab

Mike C
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    Welcome to EE.SE. We need your schematic, Mike, plus hyperlinks to the user manuals for the various devices. There's an easy-to-use schematic editor built-in on this site. – Transistor Oct 22 '17 at 17:14
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    From your description, you are either improperly connecting these, supplying them with a voltage outside of their ratings, or have faulty units. The ratings you can look up yourself; none of the rest is anything people here can help you with, as it depends on detail not included in your question. – Chris Stratton Oct 22 '17 at 18:03
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    Also with regard to the supply current rating, read https://electronics.stackexchange.com/questions/34745/choosing-power-supply-how-to-get-the-voltage-and-current-ratings – Chris Stratton Oct 22 '17 at 18:05
  • Thanks for the responses, I have added a schematic and some specs on the driver. Regarding the possibility of faulty units, I have used several from different sources, including DRV8802 which is functionally similar and I had the same problems. I am doing something wrong. Regarding the voltage ratings, I am well within the specified voltage which 5.5v-36v for the motor (I am using 24v and verified it using a meter and used different power supplies). And I am applying 5v for the logic. This problem occurs even with no load and with no stepper connected. – Mike C Oct 22 '17 at 21:24
  • And the link to the datasheet for your actual controller / driver? – Transistor Oct 22 '17 at 21:28
  • Just to clarify, the driver specs for the motor input allow for 5.5 to 36v, I didn't mean for the motor itself. – Mike C Oct 22 '17 at 21:33
  • The links for the chip/driver info were added to the top of the original post. Thanks. – Mike C Oct 22 '17 at 21:35
  • Sorry, nothing obvious to me except that you don't have the BRA and BRB terminals connected. – Transistor Oct 22 '17 at 21:40

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I do not have the reputation to comment...so here goes. It looks like you do not have the ground for the motor supply and the ground for the logic supply connected together. Try that out!

whitegreg56
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My guess is that there's a voltage spike at the point of initial turn-on. See https://www.pololu.com/docs/0J16/all for a technical description of this and some ways to mitigate it, but basically you want to put a couple caps (with very specific properties) between Vm and ground.

As Chris Stratton kindly suggested, try swapping out another supply. Ideally, one with a current limiter to prevent more boards from letting the smoke out.

Adam Di Carlo
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  • That's an interesting point - more generally, something should be done to verify that the power supply is operating properly and not spiking overvoltage. Many another supply (even if only 12v) should be tried. – Chris Stratton Oct 23 '17 at 02:52