Hi @Alex Rössler,
first of all I would like to make a note: you are working in voltage mode, why have you the shunt resistor?
The shunt resistor is needed when you work in current mode.
When the motor is driven using the voltage mode approach, a stall condition corresponds to an unexpected increase of the phase current.
The powerSTEP01 measures the load current of each phase sensing the VDS voltage of the low-side power MOSFETs.
In your case you have to calculate the stall threshold taking into account also the drop on the sense resistor.
For example if you want to set a stall threshold of 2.5 A:
you can estimate the drop on the MOS using the Rdson --> Vstall = 23 mOhm x 2.5 A = 57.5 mV
In this case I suggest to round up to 62.5 mV (STALL_TH = 00001).
If you have the sense resistor: Vstall = (23 + 30 ) mOhm x 2.5 A = 132.5 (Vstall_th = 156,25 mV).
There is no general rule, but when you set the stall threshold you should taking into account some points:
- the Rdson variation in temperature
- lower threshold is more sensitive to a noise
- the Stall detection performances can be reduced in the following conditions:
- low speed (negligible BEMF value)
- high speed (current can be low because the low pass filtering effect of the inductor)
With regard to the overcurrent threshold the load current of each half-bridge sensing the VDS voltage of the all integrated MOSFETs.
The first two points of the previous list also apply to the OCD threshold.
