STM32U535CETx Power Consumption Reduction

[Ka_T]

Hello there,

We are designing the STM32U535 to operate in a low-power configuration. According to the datasheet, the current consumption in Run mode is 16.3 μA/MHz at 3.3 V, which is quite low. However, when measuring the actual device, even after subtracting the current used by the components on the board, we observe the following:

• System startup: 1.5 mA
• System clock setting: 6.4 mA

These values indicate that a significant amount of current is being consumed.

The main clock settings are as follows:

• High-Speed Clock (HSE): Crystal
• SYSCLK: 16 MHz, HCLK: 16 MHz
• Low-Speed Clock (LSE): Crystal
• USB: 48 MHz
• MCO: 8 MHz

Given this configuration, what settings are necessary to achieve further power consumption reduction?

Thanks and regards

Ka_T

[Imen.D]

Hello @Ka_T 

There are different ways to slow down the consumption:

• Low-power modes
• LPBAM (Low-power background autonomous mode - for STM32U5 series)

To optimize Power Consumption on STM32U5, I advise you to follow this Application note:

• How to optimize power consumption on STM32U5 MCUs - Application note AN5652

Using LPBAM mechanisms optimizes automatically the Power consumption. 

For more details, I suggest you refer to these resources:

• Getting started with LPBAM - stm32mcu
• Application note STM32U5 series power optimization using LPBAM (AN5645)

I hope these resources are helpful for you.

[Ka_T]

Hello Imen,

Thank you for your response. I understand that LPBAM is primarily focused on operating in STOP mode while maintaining functionality.

While my main focus is on controlling in run mode, are there any effective power-saving strategies for run mode? Does the LPBAM concept also include run mode?

Thanks
Ka_T

[Imen.D]

Ah Ok, so you are using Run mode ! In this case, you can check these articles :

• Tips for using STM32 low-power modes - STMicroelectronics Community
• Getting started with PWR - stm32mcu

LPBAM is supported in Stop 2 mode (not for Run mode)

[Ka_T]

Thank you for providing the new materials.

I am considering using Low-power run mode to manage the system in RUN mode.

However, I could not find HAL_PWREx_EnableLowPowerRunMode(); in the HAL Driver.

Does the STM32U535 support Low-power run mode?

Thanks
Ka_T