Sleep, stop and standby modes do not significantly reduce current consumption

[j_filipe]

Greetings, 
I'm having an issue with low-power modes. I'm using a STM32U585 MCU and while in run mode it is consuming around 100mA, which is a lot. I tried to enter in Sleep, Stop and Standby modes right after the main declaration:

int main(void)
{
   HAL_Init();
   SystemPower_Config();
   SystemClock_Config();
   PeriphCommonClock_Config();

   HAL_PWR_EnterSTOPMode(PWR_LOWPOWERREGULATOR_ON, PWR_SLEEPENTRY_WFI);

   ...

The thing is, the current just drops from 100mA to 70mA, which is still a lot. 
Any clue why the circuit is consuming so much current? 

Thank you

[j_filipe]

Note: 
In the HAL_PWR_EnterSTOPMode function, the 2nd argument is PWR_STOPENTRY_WFI, not Sleep.

[Andrew Neil]

You need to give more details: How to write your question to maximize your chances to find a solution.

In particular, what hardware are you using?

How are you measuring the current?

How are you sure you're measuring only the MCU's current consumption?

Have you tried the ST examples on an ST board?

[KDJEM.1]

Hello @j_filipe;

I recommend you to refer to How to minimize the power consumption in low power mode: An example using NUCLEO-F401RE board FAQ to minimize the power consumption. The purpose of this article is to share tips for power consumption optimization while describing steps to achieve it.

Please set all free pins as analog to optimize the power consumption.

I advise you to look at  PWR_STANDBY and PWR_SLEEP examples may help you. 

Thank you.

Kaouthar

[TDK · Accepted solution]

100 mA is too much for the CPU alone. My guess is other components on the board are using most of that current.

[Andrew Neil]

@j_filipe for the benefit of others who may find this while looking to solve a similar problem, it would help if you would say where the excess current was going.

[j_filipe]

Hi Andrew, 
It is irrelevant because I am just using this MCU in a personal project, so it is a personal custom-made board. The excess current was going to another component of the circuit. 
Thank you.

[Andrew Neil]

Not irrelevant at all: a great example that the MCU is not the only thing which contributes to "low power" - something which is often overlooked!

So thanks for sharing.