How to measure the MCU power consumption

[cyt]

Posted on June 04, 2018 at 07:48

How to measure the MCU power consumption

When entering the stop mode, how to measure the power consumption?

Thanks

#mooc #stm32l4 #stop-mode

[Artur IWANICKI]

Posted on June 04, 2018 at 08:54

Hello,

If you are using any of ST boards (Nucleo, Discovery) there is always a dedicated jumper marked usually 'Idd' where you can connect your meter and measure current consumption.

There is as well quite nice dedicated board (

http://www.st.com/content/st_com/en/products/evaluation-tools/product-evaluation-tools/stm32-nucleo-expansion-boards/x-nucleo-lpm01a.html

) which allows you to measure current consumption and your application power profile.

#stop-mode

mode means that all high speed clocks are switched off. Only low speed external clock can be active (if RTC is configured), thus to measure the power consumption the best is to measure surrent consumption on Vdd line of the MCU (as Vdd and Vdda should be on the same level in most of STM32).

Please remember that STOP mode is not modifying your IO lines states, so to limit current consumption please perform any IO lines reconfiguration (the best is to use analog mode) to limit current consumption.

What I would like to recommend to you is to have a look at one of our free

#mooc

trainings where we are demonstrating each of low power modes (on STM32L4 example). You can see a bit more about this session

http://www.st.com/content/st_com/en/about/events/events.html/ultra-low-power-stm32-extras-mooc.html

.

The session is active on our learning portal

https://st-mooc.udemy.com/stm32l4_ws_mooc/

(requires free registration by posting

mailto:[e-mail]

).

Another option could be a lecture of one of our dedicated application notes (i.e. for

#stm32l4

lines we have

http://www.st.com/content/ccc/resource/technical/document/application_note/9e/9b/ca/a3/92/5d/44/ff/DM00148pdf/files/DM00148pdf/jcr:content/translations/en.DM00148pdf

or

http://www.st.com/content/ccc/resource/technical/document/application_note/5c/cb/90/97/4b/84/4e/81/DM002165pdf/files/DM002165pdf/jcr:content/translations/en.DM002165pdf

).

Hope it helps.

Best Regards,

Artur

[cyt]

Posted on June 04, 2018 at 09:10

hello,

VCC3V3 connects to the following vdd pins

VDD1

VDD2

VDD3

VDDA

VDDIO2

to measure the mcu power consumption,

I need to measure all Idd between VCC3V3-VDD1, VCC3V3-DVV2, VCC3V3-VDD3, VCC3V3-VDDA, VCC3V3-DVVIO2, then sum up the current?

Thanks

[Artur IWANICKI]

Posted on June 04, 2018 at 09:22

Hello,

The best would be to measure current consumption at one point Vcc3V3. If not possible sum of all mentioned currents will give you an answer.

Best Regards.

Artur