Current consumption in stop mode using B-L072Z-LRWAN1

[Remco Groenendaal]

Posted on May 03, 2017 at 11:42

Does anyone have any experience with the current consumption when using B-L072Z-LRWAN1 (STM32L072 and LoRa board) with i-cube-lrwan 110?

I can't get the current consumption below below 1.1mA no matter what i try. In lowpower (stop) mode all pins are set as analog, clocks are disabled, debug is off.

- I checked the device going into STOP mode

- Configured all non-connected pins to GPIO_MODE_ANALOG, GPIO_NOPULL

- Configured connected pins (UART, etc.) to GPIO_MODE_OUTPUT_PP, GPIO_NOPULL, and set to zero

I also stopped the debug clock in the ARM:

  __HAL_RCC_DBGMCU_CLK_ENABLE( );

  HAL_DBGMCU_DisableDBGSleepMode( );

  HAL_DBGMCU_DisableDBGStopMode( );

  HAL_DBGMCU_DisableDBGStandbyMode( );

Also TCXO is Off.

Still the current consumption is above 1 mA.

Anyone out there that managed to get the current down?

Thanks!

#lora #b-l072z-lrwan1

[Lukas Hegetschweiler]

Posted on December 12, 2017 at 12:05

Hello,

I have a technical question about the sleep current consumption. The results you get here is around 4 uA. Thats ok, but less consumption should be possible.

I configured my B-L072Z-LRWAN:

-

TCXO connect to PA12

- Compile the code with no DEBUG, no TRACE, no SENSOR_ENABLED,

- LED7 disconnected by opening SB18

- SB37 removed to release the RESET

Then I get 1.6 uA with some repetitive current peaks in sleep mode. This leads also to around 4 -5 uA (Measured with the Power Analyzer)

Now the when I look at the datasheet The MCU(

STM32L072CZ)

should consume 0.855 uA with RTC on and the SX1276 consumes 0.2 uA in sleep mode.

So when looking at the datasheets I should get a sleep mode of around 1.055 uA.

How can I reach this value? Is it possible with the development kit (B-L072Z-LRWAN)?

Are there some official sleep current values of the

B-L072Z-LRWAN

? I cant find them..

Kind Regards,

Lukas

[Jin ho An]

Posted on December 13, 2017 at 08:52

Hi.

Comment out the HW_AdcInit () function.

//    HW_AdcInit();

[Andrew Neil]

Posted on December 13, 2017 at 12:32

There is another (potential) leakage path which is not documented - and doesn't even have a solder bridge or jumper to disconnect it!

>:(

See:

https://community.st.com/0D70X000006SsOaSAK

EDIT (Jan 2024): That link seems to be broken (by a forum update?) - try this:

https://community.st.com/t5/stm32-mcus-wireless/excess-current-consumption-running-b-l072z-lrwan1-from-battery/m-p/322961/thread-id/13092

[Andrew Neil]

Posted on December 13, 2017 at 12:35

With SB19 intact, or JP2 fitted, there seems to be some significant current draw on VDD_USB_LRA ...

[Lukas Hegetschweiler]

Posted on December 14, 2017 at 09:18

That was it! Thanks. I am down at 1.2 uA in sleep mode.

Is there any possibility to go lower? Use another sleep mode or something?