Nucleo64 Power Measurement

[Konami]

Posted on February 26, 2018 at 17:34

I'm measuring the current on JP6 (IDD) and I see 4mA at the lowest when running the Power_Management sample or even holding the MCU in reset. I am powering the board via the USB connector. Is this incorrect?

I've tried using SLEEP_MODE, STANDBY_MODE, and STOP_MODE defined, and they all show around 4mA

Nucleo-F411RE

[Andrew Neil]

Posted on February 26, 2018 at 17:37

Have you disconnected everything else from the microcontroller - ST-Link, LEDs, Buttons, etc, etc, ... ?

See:

https://community.st.com/0D50X00009XkWhGSAV

- and follow the links ,,,

[Bogdan Golab]

Posted on February 26, 2018 at 18:09

VDD is used only for target MCU.

ST-LINK uses 3.3V directly - VDD is delivered through the JP6. So it seems that the ST-LINK current is not counted into total current consuption.

Button uses pull-up resistor (when pressed 3.3V/4.7k =0.7mA ) and LED ((3.3-1.6)/0.51k = 3.3mA) if enabled adds its current. I believe that the LED is off during the test and the button was not pressed.

Not sure what board you use to see the relevant datasheet data

[Bogdan Golab]

Posted on February 26, 2018 at 18:11

The schematic shows these details:

http://www.st.com/content/ccc/resource/technical/document/user_manual/98/2e/fa/4b/e0/82/43/b7/DM00105823.pdf/files/DM00105823.pdf/jcr:content/translations/en.DM00105823.pdf

 

[Andrew Neil]

Posted on February 26, 2018 at 18:14

Bogdan Golab wrote:

ST-LINK current is not counted into total current consumption.

But there will be leakage from the target MCU back through the connections.

[Bogdan Golab]

Posted on February 26, 2018 at 18:18

This would be bad design....

[Bogdan Golab]

Posted on February 26, 2018 at 18:22

3.3V is used for st-link, VDD for target MCU. The current flows from 3.3V toward VDD through JP6, and finally to the target MCU.

[Konami]

Posted on February 26, 2018 at 18:49

I've updated the question with the board (Nucleo-F411RE) You're correct in assuming the LED is off and the button is not pressed. I see 23mA when the application is launched (flashing LED) and 4 after going to sleep. I also see 4 if I hold the reset button

[Bogdan Golab · Accepted solution]

Posted on February 26, 2018 at 18:53

Look at the table 26 (I guess we are talking about Sleep Mode), check the frequency to see if what you see is far from what is expected:

http://www.st.com/content/ccc/resource/technical/document/datasheet/b3/a5/46/3b/b4/e5/4c/85/DM00115249.pdf/files/DM00115249.pdf/jcr:content/translations/en.DM00115249.pdf

 

[Konami]

Posted on February 26, 2018 at 18:55

No I haven't disconnected anything. The user manual for the board indicates that simply measuring IDD should give the STM32 current  consumption. Do I need to remove components? That seems like a really ineffective feature if that's the case.

http://www.st.com/content/ccc/resource/technical/document/user_manual/98/2e/fa/4b/e0/82/43/b7/DM00105823.pdf/files/DM00105823.pdf/jcr:content/translations/en.DM00105823.pdf