Pin function and do i need them

[dcorreia]

Hello,

This is my first time using a stepper motor IC and I am bit unfamiliar with how they work. I have read through the data sheet and I am still a bit unsure of a few things

Here are a few question:
1) CPN and CPP pin: Is the Charge pump internal or external as far as I can see it's external to pins CPN and CPP, but if that the case how does it switch all the capacitor into series? So could some explain to me what CPN and CPP are used for.

2)VBAT pin - I am not using a battery supply on the IC so would I still need to hook up Vbat? Why is there even a Vbat pin?

3) SWI pin- What is this pin used for. As far as i understand it used to tell if the stepper motor is on or off is that correct?

Thanks

[TRINAMIC_SK]

Hello,

basically, your assumptions are not that bad:

1) CPN/CPP are for the charge pump. As it is not possible to integrated the required capacitor for the charge pump directly in silicon, an external charge pump capacitor is connected to these pins. The application diagram in the TMC223 datasheet (www.trinamic.com) shows how to do it and what capacitance you should use.
On the other hand, VCP connects the external charge pump filter capacitor to VBAT.

2) VBAT pins: Although the name "battery" supply voltage is a bit misleading, this is the supply voltage for the drivers and the motor.

3) This is an input for a reference switch (if you have one in your application). It is NOT to tell of the motor is on or off. This pin is not digital. See the application diagram in the TMC223 datasheet on how it is connected.

Best Regards.