STM32L4S7VIT power consumption issue in power-down modes.

Brajp.1 · ‎2021-09-20

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?

TDK · ‎2021-09-20

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 · ‎2021-09-20

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 · ‎2021-09-21

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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Brajp.1 · ‎2021-09-21

Current consumption in all the stop modes is around 2mA, but it should be in uA.

The result is like for STOP0 and STOP1, MCU is going to sleep and waking on PE0 interrupt but for STOP2 MCU is waking but after that, it is not going to sleep and other functionalities like led on, etc. are also not working which are working in STOP0 and STOP1 mode after waking from power-down mode.

Regarding the schematic, if I'll got permission to share then I'll update it.

Brajp.1 · ‎2021-09-21

Kindly find the attached schematic of MCU.

TDK · ‎2021-09-22

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 · ‎2021-09-22

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

Brajp.1 · ‎2021-09-23

We did some changes to our board and now we are getting around 300uA current consumption in stop2 mode, but I am facing 1 issue in STOP2 mode is after triggering interrupt on PE0 pin MCU is waking but then it is not going to sleep again and also led on and other things are not working, but with STOP0 and STOP1 mode I am not facing these kinds of issue.