DRV2511-Q1: Motor Limiting

Hi Josh, 

The schematic looks okay to me. 

Can you monitor the PVDD voltage before, during, and after the fault? What are these voltage levels?

Does it appear that the device is over heating?

What is the impedance of the motor?

Regards,
Sydney Northcutt

Hello Sydney,

The PVDD voltage is 12v
The device is not overheating according to Flir camera
8.2 ohm impedence (a solenoid)
running on bench power supply

Thanks
Josh

Hi Josh, 

Thank you for the information. Is there a 100kohm pull up for INTZ on a different page of the schematic? If not could you try adding one? Additionally, what is the pull up voltage?

Are there other external components connected to the load?

Regards,
Sydney Northcutt 

Sydney,
I added the 100k resistor, but it made it much worse.
The pull-up voltage is 3.3v
nothing connected to it but the solenoid at the moment. We are just trying to bench test a board.

Hi Josh, 

What do you mean makes it much worse? Is a fault triggered (INTZ pulled low) more often or constantly?

If you do the same tests with the solenoid disconnected, is the issue still present?

Regards,
Sydney Northcutt 

Sydney,
Before resistor it would last 40 seconds before fault, with resistor it was 5 seconds for a fault.

I'm going to try to build a new board with just micro and driver populated tomorrow morning. Maybe the board or driver are at fault.
I'll update if it fixes.
Thanks,

Josh

Sydney,

I made another board and having the same issue. Any other ideas?

Hi Josh, 

Interesting. Ill do another schematic review to see if anything else could possibly be causing the issue. 

Regards,
Sydney Northcutt 

Hi Josh, 

In the schematic there is a note about applying voltage to the output pins. On a new device, without this voltage applied to the outputs, does the error still trigger? Is this happening across various units?

Can you provide some scope screen shots with INTZ, PVDD, and the inputs? 

Regards,
Sydney Northcutt 

YEL=ENABLE

PPL=CNTRL A

GRN=CNTRL B

BLUE=FAULT/INTZ

YEL=ENABLE

PPL=CNTRL A

BLUE=FAULT/INTZ

GRN=+12V/PVDD

Sydney,

Sorry for the old scope, its all I got right now,.

The yellow looked to be PWM, but its only resetting the fault

Thanks,
Josh Christie

Sydney,
I ready in the datasheet the following and tried it....:"When the "Latched" conditions happen, the device must be reset with the EN signal in order to clear the fault. If automatic recovery from these conditions is desired, connect the INTZ pin directly to the EN pin. This allows the INTZ pin function to automatically drive the EN pin low which clears the latched condition.

When I tied the 2 pins together, it now lasts about 30 sec before it stops. I'm at a lose as to why this would affect it in that way.

Thoughts?

Thanks,
Josh Christie