Measuring power consumption of NUCLEO-N657X0-Q using ST probes

[brianon]

Hi,

I'm wondering if there are any recommendations/guidelines when trying to measure power consumption on the Nucleo-N657X0-Q when running a neural network model, both with NPU acceleration and without on the CPU for comparison. I have access to both a X-Nucleo-LPM01A power shield and a STLINK-V3PWR and do not know which one to choose.

Are both options rated for enough power to measure the board? And does any of the two options require removing components, as the board is borrowed so I would prefer a non-invasive solution.

Thanks in advance!

[David SIORPAES · Accepted solution]

Hello,

There is a well documented application that shows how to do power measurements on a DK board.

It should be pretty easy to adapt it to a Nucleo board:

https://github.com/STMicroelectronics/x-cube-n6-ai-power-measurement

It makes use of STLINK-V3PWR but you need hardware modifications though.

David

[brianon]

Hi @David SIORPAES,

Do you know if the X-Nucleo-LPM01A approach would also require hardware modifications? If possible I would prefer not to make any hardware modifications as I am still relatively new to working with ST boards.

[David SIORPAES]

Hello,

Being the X-Nucleo-LPM01A a power source too, it would need the same hardware modifications.

The least invasive procedure is to remove R40 and measure the voltage drop on R41 as described here: 

Measuring Current on NUCLEO-N657X0-Q - STMicroelectronics Community

You can then leave R40 unsoldered.

David

[brianon]

Hi again,

I see, in that case do you know what the Nucleo-N657X0-Q equivalent components would be for the R23, R24, and C27 that should be removed for the Discovery Kit?

[David SIORPAES]

Yes, according to Nucleo schematics at page 9 

The equivalent components are: R28, R19 and C21

[brianon]

Hi,

Thank you for that, the last thing I would want is to remove the incorrect component.

Regarding the other solution with R40, I'm assuming that it refers to section 7.4.4 in um3417? If so, for my case where I wish to measure the power consumption of the board when running a neural network model using the stlink-v3pwr, would I also remove R40 and measure pin pair 3/4 or would it in my case be R28 with pair 1/2?

[David SIORPAES]

The solution with R40 requires to measure the voltage drop using an oscilloscope or other instrument on CN12 3-4 pins. You cannot use a power source such as STLINK-V3PWR to accomplish this.

This solution has the non negligible advantage that the required hardware modifications are less invasive (just remove R40).