Maximum current rating of STEVAL SPIN 3201

[R.Ravi1]

Hi,

I'm trying to use SPIN3201 to run a bldc motor and the maximum current rating of the motor that i want to use exceeds SPIN 3201 rating, although SPIN 3201 is rated for 15A i don't see whats capping the maximum rating as the MOSFETS are rated for 80 A.

And what hardware modifications can i make to SPIN3201 to run a motor with 25A nominal current.

[Dario CUCCHI · Accepted solution]

Hi @R.Ravi1​ ,

welcome to the ST community !

The actual limit of 15A is given by the power dissipation of the MOSFETs.

Using currents above this limit can cause an overheat and a permanent damage of the power MOSFETs.

As you correctly said, the MOSFETs are 80A rated, but this is the maximum current limit in an almost ideal condition, so keeping the temperature of the MOSFET stable.

On the PCB in a free environment power dissipation makes the temperature to increase.

The thermal resistance depends mainly on the PCB layout, let’s say on the amount of copper connected to each MOSFET, which acts as a heatsink.

Unfortunately it is not possible to modify the STEVAL SPIN3201 to run continuously a motor at 25A, since a PCB redesign with different MOSFETs (with lower Rds,on) is needed.

I can suggest to evaluate your application using the motor at lower currents to explore all the features of the STSPIN32F0.

Then, you can redesign a power stage suitable for your target current.