Pololu Motor Driver Carrier is getting heated


I am using TB67S279FTG compact stepper motor driver. I am setting its current limit value by adjusting Vref voltage as mentioned in the TB67S279FTG link for the motor driver info.

It says, " This compact version uses a TB67S279FTG driver and can deliver approximately 1.1 A per phase continuously without a heat sink or forced air flow (up to 2 A peak)."

Current limit = Vref x 0.556 A/V

I am setting Vref = 1.6V, which roughly says current limit as 0.89 A

which less than 1.1. And my driver is getting heated. Why it is happening, all suggestions are welcome

As the product page clearly states, the driver can get hot enough to burn your finger under normal conditions.


Jim is correct; it is normal for the driver to get too hot to touch during normal operation. Is everything else behaving as you expect?


Hi Claire,

It does not get hot during normal operation when I set the VREF < 1.0V, If VREF > 1.0 V(i.e. 0.556 A limiting current), it starts to heat.
And product page says, it can deliver 1.1A continuously without heat sink. Can you explain me the the relation between limiting current setting and continuous current rating of driver.


The continuous current rating is the maximum current limit setting we were able to set the driver to and have it not overheat while driving a motor. The driver’s thermal shutdown threshold is between 145-175 °C, so I expect the driver to be close to that hot when handling 1.1A. The lower the current limit (and thus the current through the driver) the cooler the board will be.