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Hi all,

 

I'm trying to measure how much current my board draw in EM2 and EM4 mode. I've disabled all the peripherals but I can't get better than 300µA in any mode. I would expect to have much less for the EM4 mode but I don't see any difference right now.

 

I'm powering my board through the pins EXP20 and EXP1. I'm using the soc-thunderboard example and here is the changes I've made to it :

 

This is my last test before we can choose which product we'll use, thanks in advance for your help  :)

 

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  • Any ideas ?
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  • hi Clarck,

    I'm going to do the test, and get back to you soon.

    Thanks

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  • The BG22 Thunderboard can be powered by USB cable, the 3v coin cell battery or the mini Simplicity connector, I just connect the Mini Simplicity connector of the Thunderboard to one WSTK, and measure the current consumption of the Thunderboard using energy profiler. The average current consumption is around 8.2uA using the source code you provided.

    And you can get the similar testing result by powering the Thunderboard through the pins EXP2 (VMCU) and EXP1 (GND).
    More information about the power supply of Thunderboard, please see section 3.2 of UG415.

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  • Thanks for your answer !

     

    Ok so I have way better results now but I still have one question : How do you explain the differences between the values we have and the specs that announces 0.17µA in EM4 and 1,75µA in EM2  ?

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  • Some of the peripherals contribute part of the current consumption, please refer to the example here for a better test result.

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  • For BG22 you may consider to try example under S2, not S1.

    https://github.com/SiliconLabs/peripheral_examples/tree/master/series2

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  • I've just tried these examples, the best i can get is 7µA. Any ideas to have a lower power consumption ? Do you manage to measure nanoamps with these examples ?
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  • I am wondering what current consumption you have got with BG22 TB board now.

    To get the target current in the datasheet, you absolutely need to pay attention on the condition the data was gotten.

    Take EM2 with DC-DC as example, the 1.4uA EM2 current condition was listed on top of the table.

    but if you take a look at the schematic of the thunderboard BG22, the AVDD/IOVDD was powered by VMCU directly (not DC-DC output).

     

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  • Thanks for your answer.

     

    Ok so I've tried measuring the consumption with the same conditions as the datasheet says. I tested to get the same results as the section "4.6.3  MCU current consumption at 1.8 V" -> now  my power supply =1,8V and VDCDC is bypassed 

     

    The best I could get is 6µA. It's better thaan the 7µA I had but that's not it. Do you have other ideas ?

     

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  • Help, please
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  • Hi,

    Can you clarify how you are measuring that current? If you are using a WSTK in debug-out mode then be aware that it can cause leakage. This is in the board errata, table 8.2 of UG415.

    Did you set the debug mode to off? Otherwise there could be some leakage into the board controller.

    If those two things don't lower the current then there could still be small leakages. The TB BG22 is not a good platform to verify datasheet current consumption figures. If that is what you are going for then I strongly recommend that you purchase a development kit and make those measurements with a radio board.

    https://www.silabs.com/products/development-tools/wireless/efr32xg22-wireless-starter-kit

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  • No I just have a BG22 TB.

    I am powering my board through the pins EXP2 and EXP1, so i just put an ampermeter between my power supply and the pin EXP2.

     

    How would I set the debug mode to off ? I'm just using the on-board debugger and from what I saw, when not used the on-board debugger goes into a very low power shutoff mode (EM4S), consuming around 80 nA typically

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  • How would I set the debug mode to off ?

    Click on "Change" in front of the Debug Mode

    Change debug mode to OFF

    when not used the on-board debugger goes into a very low power shutoff mode (EM4S), consuming around 80 nA typically

    This is not about the current consumption of the debugger but rather making sure that the relevant debugger pins are tri-stated and don't contribute to any leakage.

    I will insist on recommending the wireless kit if you really want to measure datasheet figures, the thunderboard may have some leakages which will be very time consuming to trace and eliminate and that alone justifies buying the other kit.

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