DRV11873: Intermittent Initial Motion Poor

Hey Cho,

I'll need to discuss this with my team. I'll get back to you as soon as possible (either tomorrow or early next week).

Regards,

Paul

Hi Paul,

Is there any update on the review result?

Hey Cho,

Sorry for the delay here.

The DRV11873 has no way, to my knowledge, of holding the supply low and then releasing it. Could you ask your customer to perform a continuity check between the phases and the supply and GND to see if the FET is damaged?

Regards,

Paul

The customer checked the problem of the surrounding device.

However, there was no problem with nearby devices such as FET.

In addition, normal operation is performed on the 12V input without motor short detection section.

Hey Cho,

I'm a little confused by this statement "normal operation is performed on the 12V input without motor short detection section". Are you saying sometimes they don't see the motor short detection section? And if so, in what case do they see it? And are they able to reproduce this result consistently?

Regards,

Paul

Sorry for the late reply.

Customer deleted motor short detection section (2.3V) and entered 12V.

See figure.

Problems can be identified consistently.

Hey Cho,

So it seems the device works with the motor short detection section removed. Seeing as the motor short detection is implemented by your customer, have they been able to successfully start up a board with this section included?

Additionally, does your customer have other boards they can test? If so, do they see the same behavior across all their boards?

Regards,

Paul

Hi Paul,

Sorry for the late reply.

So it seems the device works with the motor short detection section removed. Seeing as the motor short detection is implemented by your customer, have they been able to successfully start up a board with this section included?

-> Only the problem board does not work. The other boards operate normally even after short detection.

Additionally, does your customer have other boards they can test? If so, do they see the same behavior across all their boards?

-> Only the board in question doesn't work. The customer has one more board that doesn't work. The attachment is the remaining one board waveform.

1) Yellow: Vcc (12V after initial short detection voltage 2.05V)

2) Green: PWM (Duty 0 to 100% condition for motor soft start for 1 second)

3) Purple: FG

4) Sky blue: Current wave shape

Bad Wavefrom : 

Normal Wavefrom : 

Hey Cho,

Since it seems only the one board is not working. Could you ask your customer to perform an A-to-B swap? What I mean by this is, could they try swapping the DRV between the non-working board and a known working board. And then perform the same test as before. This should help us determine if it's an issue with the board or the DRV itself. 

Regards,

Paul

Sorry for the late reply.

The customer has confirmed that the swap test results are working properly when replacing the ic.

ICs with bad behavior did not work even on normal boards.