DRV8323: nFault momentarily drops when trying to supply PWM signals

Eyal Kurz

Prodigy 60 points

Part Number: DRV8323
Other Parts Discussed in Thread: LAUNCHXL-F280025C

Tool/software:

Hey,

We're trying to run the Universal Motor Control Lab on our custom made PCB.

We are currently trying to run BUILD_LEVEL_1. Therefore, the motor isn't connected to the PCB.

We made sure all the connections in our PCB are similar to those of the Evaluation kit(LaunchXL-F280025C + BoostXL-DRV8323RS).

Only difference is that we use the DRV8323S driver on our PCB, and we already verified the SPI communication is working properly between the MCU and the driver.

I am providing the nFault signals as were captured by the scope, hoping it will assist the debugging process.

I would add that when debugging, and going step-by-step through the code sections that seem to cause the nFault to drop, the drops don't happen.

We also placed 33nF capacitors in C9, C10, C11 (boostxl-drv8323RS schematics) as mentioned in the Universal Motor Control Lab user manual.

Thanks,

Eyal

2 months ago

0 Yara Al Shami 2 months ago

TI__Genius 16415 points

Hi Eyal,

Are you having to clear the fault or is the fault pin recovering by itself? Depending on this, this will tell us what the fault most likely is.

Regards,

Yara

0 Eyal Kurz 2 months ago in reply to Yara Al Shami

Prodigy 60 points

Hey Yara, thanks for the reply.

The pin recovers by itself.

0 Yara Al Shami 2 months ago in reply to Eyal Kurz

TI__Genius 16415 points

Hi Eyal,

Next step would be to disable VDS_OCP and SEN_OCP to see if the issue persists, if it does then you are most likely dealing with UVLO or CPUV. In this case you would have to check the stability of your supply.

If the issue does go away then you were likely running into overcurrent events

Regards,

Yara

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DRV8323: nFault momentarily drops when trying to supply PWM signals