DRV8426: Changing the current scale

hello, David,

DRV8426 uses analog voltage VREF pin to change the full scale current setting. Could customer use a switch to switch the VREF setting or short out a resistor in the resistor divider to realize TRQ pin function as DRV8885?

Regards,

Wang Li

Hi Wang

Thanks for your reply.

The customer did not provide much information except what I mentioned in my question.

I'm not sure if I had this correctly so could you check if my statements below are right?

I checked the datasheet and noticed that the TRQ pin of DRV8885 is a tri-level pin and the level of the current scaling differs according to the level of the TRQ pin at 0, Z, or 1, corresponding to current scaling 50, 75, or 100%. Is my understanding correct?

While the DRV8426 does not have a similar setup and is required either to use a DAC or to use a switch/resistor to control the voltage on the VREF pin. With that being said one way or another the customer will still need to add additional components to their design to make the current scaling works if they decide to go with DRV8426, is that right?

As their main concern currently is to lower the cost, I think they will need to evaluate which solution is less expensive for them. I'll bring the information you gave me to them to check their feedback.

Regards

David

Hi Wang

Could you check if the image below is right simple setup to set the TRQ for 0, Z, or 1?

Also if you could show some circuit examples that customer could use to setup the TRQ pin it would be helpful.

Regards

David