How to reduce the power consumption of a Nucleo board? (Nucleo-STM32H7A3)

[TomC]

I am producing a prototype and will not be making a custom PCB therefore I need to try to reduce power consumption of a Nucleo-STM32H7A3 development board.

With the microcontroller in standby mode (approx. 3uA) the dev board itself consumes 6mA running on a 3.3V external supply. I do not have a specific current draw target but as low as possible would be optimal. Please let me know if you have any ideas where the current draw might be coming from, thanks.

[LCE]

Which dev board exactly?

Go through the schematics and check the usual suspects:

• voltage regulators have quiescent currents between < µA and > mA
• any other stuff connected to the supply voltages, pull-up Rs at the IOs, LEDs, other ICs, other voltage regs, references, ...

[Javier1]

Remove the jumpers powering the builtinSTLink and use the USER USB connector to power the board.

That will help you a bit

[Andrew Neil]

The board's User Manual should have tips on how to minimise consumption by the various stuff on the board.

Do all of that first.

As you can see from this thread:

https://community.st.com/s/question/0D50X00009XkbSOSAZ/excess-current-consumption-running-bl072zlrwan1-from-battery

The User Manuals don't always tell the complete story - so, as @Community member​ said, you may need to go through the schematics looking for potential "leakage" ...

[gregstm]

Has your Nucleo board got one of those jumpers that allows you to measure the current going to the micro? If so, you could remove that and supply the power directly to the micro from there. The jumper is after the regulator. On the nucleo boards I am using at the moment (Nucleo-64 STM32L476RG) the output of the regulator is fixed at 3.3V and has an always-on Red Led that consumes about 2mamp next to it (I replaced the 1K Led resistor with 15K, but that is still quite bright - just remove it if not needed). I will power my board with a 3V Lithium battery from the jumper pin (but be careful not to get voltages reversed and blow things up)

[Andrew Neil]

@Community member​ you'd probably still want to isolate the ST-Link - so you don't get any leakage out of the Target's pins to it ...