TMC262/Overcurrent Protection.

[Hansgeorg]

1.) The overcurrent protection is one of the highlights in the datasheet of TMC262. Its separated from other protections like "short to GND" or "over-temperature".
I found no detailed informations about this overcurrent protection in the datasheet. How will the event of overcurrent be detected ? At what current level this protection will work ? Can I set this protection level ?

2.) Is it possible, that the Flag STST sets when overcurrent occurs ? In our prototype the TMC262 seems to react on an overcurrent and it switches off both phases. There are no flags concerning short to GND. In the moment we reach this point at likely 4 A phase current.

3.) What currents (in/out) may be driven from the digital output "SG_TST" ?

[TRINAMIC_BD]

Hello,
1) In fact, this is misleading in the feature list. An overcurrent occurs when the load becomes short circuited or when the output is hard shorted (to GND, which is most probably). The chopper reacts immediately to an overcurrent, e.g. shorted coil condition by switching off, but it will retry in each cycle. The short to GND current can be influenced in a limited number of steps by tuning the short to GND detection time. This will influence the maximum current when switching into a short condition, only. If you need more finetuning, you can add a high side resistor to the highside MOSFETs (in series with each full bridge), but this will also increase power dissipation. It may make sense, when very small motors shall be driven and protected. A voltage drop of roughly 1.5V from VS to BM triggers the short detection.

2) There is no connection to STST, but OL will occur. It could be, that your power supply shuts down for a short moment due to the overcurrent, and this resets the driver.

3) You may load it with 20mA or even more, but output voltage decreases. Up to 50mA continously will not harm.