RAK811 Current Consumption



  • Hi,

    Looking at the power consumption figures on this page, the information is confusing and contradicts with each other.

    0_1489721217293_TestofPowerConsumption.jpg

    0_1489721360377_Parameter.jpg

    So, how much is the sleep current?
    TX current and RX current?



  • Sorry for your misunderstand , follow power consumption is right, we will update the parameter list!
    0_1489975256956_upload-c2b799b7-598a-4308-94dc-dade22f66ac1



  • @junhua I believe the bulk of the sleep current comes from the TCXO as it is not being shutdown although the rest of the component is put into sleep mode? I'm merely guessing but other than that, it could be IO pins in floating input state. 372 uA is just too much if you look in the market at other module. Even the unstable RN2483 is around 30-40 uA (claimed as 10 uA).

    Will you guys be updating the hardware/firmware to further optimize the sleep current to something more suitable for battery operation like at least 10-20 uA?

    Actually I like the fact TCXO is being used as it is much more reliable at SF=12 & BW=125kHz at lower/higher temperature.



  • Thanks your great suggestion, We will check our firmware or hardware to decrease the deepsleep power consumption. By the way ,what is the way to wake up from sleep.
    Yes, we currently use the TCXO .
    Thanks again.



  • @phangmoh Hi , sleep power consumption is decrease to 7.2uA . please test the attach Firmware .
    0_1490068785730_RAK811_V1023_RELEASE_868.bin



  • @junhua That is impressive. So, this is achieved with the TCXO running or totally shutdown? Or optimization were made on the pins that were floating?

    This is good news. Thank you for working around the clock for the fix.



  • @junhua Hi, I have a problem with current consumption.
    According to stm32l datasheet, in "low power run mode" one can't access I2C. Rak811 have 2 I2Cs and no accessible SPI, it means that you are using run mode not low power mode.
    The question is that why don't you use low power mode?



  • After updating the latest firmware version consumption is 27uA. this is 4 times more than 7.2 μA.
    Can anyone measure the consumption in sleep mode to compare the results?



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  • @junhua @phangmoh @stuartw @rak811 @rakadmin
    Can you please provide the C source code for this firmware? Or if I want to implement this firmware with my existing API, how can I do so?



  • @Digidenis said in RAK811 Current Consumption:

    After updating the latest firmware version consumption is 27uA. this is 4 times more than 7.2 μA.
    Can anyone measure the consumption in sleep mode to compare the results?

    I agree with this finding. It's definitely not 7.2 μA but closer to 30 μA.

    @kenyu may we know how you guys are measuring this setup. Using V2.0.2.2 of the firmware.



  • I can confirm. The latest firmware consumes 7.2uA in sleep mode. I took plain RAK811 module, connected to it using UART and issued command AT+SLEEP.

    When the power voltage is 3.3v power consumption should be ~9uA. At 2.6v power consumption ~7.2uA.

    If reduce the voltage further the module stops working although according to datasheet of stm32l151 and sx1276 the minimum working voltage could be lower. I think that's because there is an LNA IC on the board that has a limit of 2.6 volts.


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