PowerSTEP01, Sensorless Stall detection vs Overcurrent detection

[Gostervall]

I don't really understand how these two functionalities differ. One is measuring on both low side and high side, the other one only on low side.

The available threshold values are the same in both cases.

When would you use OCD_TH and not STALL_TH, and vice versa?

I also find that the granularity of the thresholds is way too coarse. Below my limit and the motor doesn't move, one step up and it crashes hard into obstacles. Is there any way to get a finer threshold?

[Cristiana SCARAMEL]

Hello @Gostervall and welcome to the ST Community.

The two functions you mentioned work on the same principle, that is to measure a current threshold through sensing the VDS voltage of the integrated MOSFET. However, as described in the powerSTEP01 datasheet, the purpose of the two functions is different.

The overcurrent detection is a protection against overcurrent events, while the sensorless stall detection is able to detect a motor stall caused by an excessive load torque (when the motor is driven using the voltage mode approach) so an overload condition.

The stall detection threshold can be set to a current level slightly above the operative current. The overcurrent threshold can be set to a higher value sufficient to protect the device according to your operating conditions.