DRV8876: Current protection point settings and nfault issue

Hi Cherry,

Cherry Zhou said:

However, normal operation can be performed on the reenergized energy

Can you clarify what you mean in this statement?

Cherry Zhou said:

Is it not retry because peak current is too high?

What is the IMODE resistor value the customer is using? The table below shows the different OCP and current regulation response according to the IMODE state. If the customer sets IMODE to either level3 or level4 the outputs will be latched during an OCP fault. If the want the automatic retry function, IMODE should be set to either Level1 or level2.

Cherry Zhou said:

Is it possible to set current protection point?

It is not possible to set the over-current protection trip point. It is internally set. However, you can set the current chopping (regulation) to any value below the OCP trip point. The datasheet explains how to do this. Also please read this FAQ to understand the differences between over-current protection and current regulation.

Hi Pablo,

Thanks for your reply.  NOTE: IMODE can be connected to GND on the customer's circuit.

Pablo Armet said:

Can you clarify what you mean in this statement?

The customer's IMODE setting is LEVEL 1, it will  RETRY normally, but the driver does not RETRY. The customer has tried to turn the power off and back on, the motor can turn. (Approximately 0.61A under normal motor load) This condition occurs after the motor stalls.

So the customer would like to know if the current regulation Vref can set the value of the overcurrent chopping (Set at 3.6A below DRIVER)

Or is it necessary to set the conditions for the nFAULT action?

Thanks again!

Best Regards,

Cherry

Cherry,

If the device is truly latched (will not RETRY at all) and nFAULT = low, then there are two conditions to consider per the datasheet.

I have highlighted the recovery condition to come out of this fault.  Can you check VM and also VCP voltage and see if there is some issue there?  

Regards,

Ryan