BOOSTXL-DRV8323RS: heat and noise issue

Hi Cherry,

Is the customer applying an input PWM signal to the chip, and can they share a waveform of one of these channels? Are they running anything other than writing to the SPI registers? Can they share a waveform of VM? Additionally, please have them review this document for best layout practices so they can make sure the layout matches our recommendations, as board parasitics can cause major issues if not handled correctly: https://www.ti.com/lit/an/slva959b/slva959b.pdf?ts=1688574537341&ref_url=https%253A%252F%252Fwww.google.com%252F#:~:text=Having%20one%20layer%20of%20the,prevent%20breaks%20in%20the%20plane.. 

Best,

Davis

Hi Davis,

Thank you for the support.

Davis Jackson said:

Is the customer applying an input PWM signal to the chip,

No input PWM signal has been applied and only SPI communication was done, no other operations. A DC power supply is being used.

Davis Jackson said:

please have them review this document for best layout practices so they can make sure the layout matches our recommendations, as board parasitics can cause major issues if not handled

Layout is as recommended as the document except for the thinner traces.

Thanks and regards,

Cherry

Hi Cherry,

Thank you for the feedback. Does the customer have any circuit components being supplied by the DRV8323RS's buck regulator? Are they able to share a schematic? 

The VM supply is within the device's limits, but the customer should make sure all the other circuit parameters are within the recommended operating conditions listed in the datasheet.

Best,

Davis

Hi Davis,

Davis Jackson said:

Does the customer have any circuit components being supplied by the DRV8323RS's buck regulator?

The lower line is the DRV8323RS internal buck to 5 V and then 5 V to 3.3 V to power the MCU. 

Davis Jackson said:

Are they able to share a schematic? 

Please see here:

Thanks and regards,

Cherry

Hi Cherry,

The provided schematics look fine. The customer needs to check whether there is a significant amount of current going into or out of the device, most likely into the device's VM or VIN supply pins or out of the buck switch node pin. There could be an unexpected short somewhere in the circuit that is causing a significant amount of current to flow into or out of the device and making it heat up. Please let me know what they find.

Best,

Davis

Hi Davis,

It does not heat up below 18V, so it should not be a short circuit issue? The voltage is increased before it sharply heats up. 

Thanks and regards,

Cherry

Hi Cherry,

There might not be a direct short, but some issue relating to the supply voltage seems to be causing the device to heat up since the MOSFETs are not attached or being driven. Can the customer provide an image of the VM and VDRAIN pins for both lower supply voltage and for the higher voltage at which the device starts to heat up? This should help narrow the search by determining whether the issue is at the device supply or regulator outputs.

Best,

Davis

Hi Davis,

Davis Jackson said:

Can the customer provide an image of the VM and VDRAIN pins for both lower supply voltage and for the higher voltage at which the device starts to heat up?

Please see here,

Referring to the datasheet, VM and VDRAIN are connected separately. 

Thanks and regards,

Cherry

Hi Cherry,

Has the customer tested other boards, and does this same issue persist across multiple devices? Have previous tests been run on the device before this condition occurs?

Additionally, clear the fault bits that are observed at device startup and see if any other bits show up/persist after startup. This will help separate what is occurring at startup from the issue that is causing the device to heat up.

Best,

Davis

Hi Cherry, 

Do you still require further assistance on this?
Please help mark the thread as resolved if there are no further questions. Thanks.

Best Regards, 
Andrew