MCU power consuption measurment STM32N6570-DK

[RanjithRemasan]

Hi 

I am using an STM32N6570-DK board. For my project, I need to measure the total MCU power consumption (core power plus the power consumed by the I/O pins while interfacing with the SDRAM and OSPI flash). I have reviewed the documentation regarding power measurement, but I am confused because there are multiple power supplies. Which pins on CN2 should I use for my measurements, and is there a common point to measure the total power?
How to measure power on the STM32N6 - STMicroelectronics Community

[FBL]

Hi @RanjithRemasan 

Measurements must be performed separately for each domain, and then summed manually if needed. 

> Pins 1 and 2 of the CN2 connector are used for measuring the external SMPS input current, which supplies the VDDCore domain as stated in KB.

[RanjithRemasan]

HI FBL,

Which pin are considered for the power consumption measurement for VDDcore and I/O pins.

Best Regards

Ranjith 

[FBL]

Hi @RanjithRemasan 

On connector CN2, the pins dedicated to power consumption measurements are provided:

• VDDCORE (core supply):
  • Pins 3–4 for the external SMPS VDDCORE path
  • Pins 9–10 for the internal SMPS VDDCORE path
• VDDIO (I/O supply):
  • Pins 11–12 for the I/O supply (VDDIO)

The measurement is done by inserting the ammeter in series on the relevant pin pair. For exact measurement setup and any required jumpers or links, please refer to the board user manual and schematics.

[RomainR.]

Hi @RanjithRemasan 

You can also refer to this article:
https://community.st.com/t5/stm32-mcus/how-to-measure-power-on-the-stm32n6/ta-p/816166

On STM32N657-DK VDDIO2 and VDDIO3 are powering Hexa PSRAM and Octo NOR Flash, under 1.8V by using VDDA1V8.
This can be measured on CN2:
I_SENS_VDDA1V8_P pin #13

I_SENS_VDDA1V8_N pin #14

The other VDD, VDDIO4 and VDDIO5 are powered with 3.3V (VDDIO and VDDIO_SD)

For VDDCore refer to the answer of @FBL .

Perform measurement independently on CN2 for VDDCore and VDDA1V8, then sum the results to obtain a total.
If you plan to measure voltage drop on R35 (VDDCore) and R188 (VDDA1V8) I suggest you to use a differential probe with an oscilloscope to trace the dynamic measurement (especially on VDDCore)
Best regards,

Romain

[RanjithRemasan]

Hi  @FBL  and @RomainR. ,

1) Hope that the Pins 9–10 is a feedback signal not the power consumed by MCU during the operation. Is my understanding is correct?

2) I am planning to measure the core power from I_SENS_EXT_VDDCORE_P(CN2-Pin3) and I_SENS_EXT_VDDCORE_N(CN2-Pin4). So in this case do i need to measure current through I_SENS_EXT_P(CN2-Pin1) and I_SENS_EXT_N(CN2-Pin2)?

Best Regards

Ranjith Remasan