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Brajp.1
Associate III
September 20, 2021
Question

STM32L4S7VIT power consumption issue in power-down modes.

  • September 20, 2021
  • 2 replies
  • 2920 views

I am using STM32L4S7VIT MCU.

I am using STOP2 mode to put MCU in power-down mode, for that, I am simply making all the pins as ANALOG except 1 interrupt GPIO PE0 and then calling STOP2 power-down function, but it is taking around 2 mA current it should consume a few uA, and MCU won't even waking from power-down mode on external interrupt (PE0).

How can I solve this problem?

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2 replies

TDK
September 20, 2021

Is this a custom board? If it's not waking on PE0, how do you know it's actually in stop2 mode?

Should be able to go off of an example:

https://github.com/STMicroelectronics/STM32CubeL4/blob/5e1553e07706491bd11f4edd304e093b6e4b83a4/Projects/NUCLEO-L4R5ZI/Examples/PWR/PWR_ModesSelection/Src/stop2_test.c

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Brajp.1
Brajp.1Author
Associate III
September 21, 2021

Yes, it is a custom board.

I have already followed the GitHub example code you have suggested.

Why I am saying that MCU is in the power-down mode because after calling HAL_PWREx_EnterSTOP2Mode(PWR_STOPENTRY_WFI); function MCU is consuming 2mA current, but for STOP2 mode it should consume a few uA.

TDK
September 21, 2021

Okay, and what were the results of following that example? Did the power drop down as expected or did you get the same behavior?

Is there something else on the board other than the chip responsible for consuming power? Can you show a schematic?

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TDK
September 22, 2021

Is the LED off when you're measuring current? Where exactly are you taking the current measurement?

I can't see anything jumping out at me in the schematic. Make sure all pins are in their idle state (UART should be high, LED should be off, when entering stop mode).

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Brajp.1
Brajp.1Author
Associate III
September 22, 2021

Yes, LED is off and we required wakeup from LPUART so we kept LPUART pins as GPIO_MODE_AF_PP and NOPULL

I have checked current before main MCU LDO and even after main MCU LDO but getting same result