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LP-EM-CC2340R5: standby current > 150uA

bob frankel
Expert 2460 points
Part Number: LP-EM-CC2340R5
Other Parts Discussed in Thread: ENERGYTRACE

using the gpiostandby example, my standby current seems much higher than it should be -- approximately 168uA....  here is the signal i'm seeing:

                        

i'm powering my board externally, and i have removed the 10-pin debug cable....  i've left the jumper in-place for the LED, hence the additional ~6mA of current every other second....

the generated ti_drivers_config.c file does contain a call to Board_shutdownExtFlash() as expected; but what else on my launchpad could be drawing this much current when my program is suspended????  other than GPIO, i'm not using any other drivers....

my expectations were for current in the ~1uA range....  

  • 0
    TI__Expert 5144 points

    Hi Bob,

    Can you remove the content from while loop and just add: 
    }

     while (1)
    {
        /* Sleep, to let the power policy transition the device to standby */
        sleep(100000);
    }

    With this I measure a power consumption of ~3-4 mA at my table.

    Regards,

    Alex

  • 0 in reply to Alex Paul
    Expert 2460 points

    hi alex,

    i'm now down to ~40uA -- better, but still 10x higher than i would have expected

    was your measurement actually ~3-4 uA????

  • 0 in reply to bob frankel
    TI__Expert 5144 points

    Hi Bobel,

    yes.

    Can you give me an overall description of your setup ? 

    Which peripherals are you using ? 

    Did you do any changes on your code?

    What device are you using to measure the current consumption ?

    Regards, 
    Alex

  • 0 in reply to Alex Paul
    Expert 2460 points

    hi alex,

    i'm actually implementing my own "bare metal" runtime, where i *HAVE* been able to achieve ~3-4uA of current in standby....  for what ever reason, using the gpiostandby example didn't benchmark well (for me).... i think i'm good for now....

  • 0 in reply to bob frankel
    Expert 2460 points

    a further update....  as a simple benchmark, i want to wakeup at a 1Hz rate (using the LPXTAL for accuracy) and do some trivial amount of work -- such as blinking an LED....  my expectation is that except for this brief period of activity, i would be drawing ~1uA of current when in standy....

    using my own "bare metal" runtime, i'm actually BELOW the 1uA threshold....  but when i run TI's gpiostandby example, i'm consuming >150uA (as documented above)....  i was able to lower this number by essentially having an "infinite" timeout, though i'm still not clear as to why TI's runtime can't do better over a 1 second internal....

    in general, i couidn't find a example in your SDK that achieved that achieved ~1uA of current consumption over a 1 second period....

  • 0 in reply to bob frankel
    TI__Expert 5144 points

    Hi Bob,

    Sorry for the late response, I was ooo last week.

    The standby current is expected to be higher than described in the datasheet as the GPIO unit has to be powered in this example.

    Can you maybe explain how you perform the current measurement?

    Do you use EnergyTrace for the measurements?

    If so, do you have the possibility to access any other energy measurement tool as Energy trace is not very suitable for this low currents with an accuracy of +-700 nA this will not have a very good accuracy here. However it should be enough to show that the current is not 150µA

    I repeated the measurement with energy trace and can confirm that I do not see the 150µA with the GPIO example. 

    Toggeling the red Led with a Frequency of 1 Hz:

    I see the following results using EnergyTrace:

    With set Jumper

    After Removing the Jumper it looks like this: 

    Can you please describe again how your measurement is setup and how you perform the measurement.

    Also it would be nice to know which equipment you are using to measure the current. 

    Regards,

    Alex

  • 0 in reply to Alex Paul
    Prodigy 90 points

    I am facing the same issue as the post creator is saying with almost the same values. I tried with the default standby example with SDK V7.1 and launchpad CC1312R1

  • 0 in reply to Andres Oliva Trevisan
    TI__Expert 5144 points

    Hey Andres,

    the CC1312 is SUB-1 can you please create a seperate thread for this in another folder so we can assign the thread to the corresponding expert?

    A first guideline to improve your results would be: 

    Remove all jumpers except power supply (if you power from external supply please also remove the power supply pins)

    Regards,

    Alex