7 Replies Latest reply on Aug 25, 2014 7:14 AM by MichaelF_56

    Power consumption



      I saw in a couple threads mentioning that the power consumption when a peripheral is connected, but not doing anything should be in the uA range. However my device seems to be running in the 10mA range always.

      How can I enable low power modes? I was able to but the device into deep sleep, but at that point the connection is lost.


      Do you have a recommended way to measure power consumption on the TAG board?

        • 1. Re: Power consumption

          Could you explain the use case in question.  Depending on your advertisement interval, our device can use different sleep modes:


          • For larger advertisment/connection intervals, the part can go into deep sleep where we've seen single digit uA
          • For other use cases utilizing the various sleep modes, we've seen < 30uA


          According to the team, 11mA (11uA would seem more inline) for connected non-advertising mode seems high.


          What else is connected and how exactly are you measuring current?

          • 2. Re: Power consumption

            The SW configuration is pretty much same as the hello sensor example.

            Since my post I did realize that the 11mA is not accurate, (there are other devices that are drawing some current, this is on our custom board). But still it seems that the module is using about 5mA.


            In my case I am powering the board with a DC power analyzer that displays the current consumption.


            I am not seeing anything in the uA range unless I go to deep sleep.


            Could you suggest how to measure current on the TAG board? That way we can be sure we are comparing the same thing.

            • 3. Re: Power consumption

              We have a team working on this internally, so one of them should be able to respond shortly.


              Thanks in advance for your patience.

              • 4. Re: Power consumption

                Hello ppaszkow,


                Measurements on the TAG Boards:


                BCM20736 TAG003 Board:

                1. Remove RD6 from position BC and measure current through position BC for LDOin current.
                2. This will be the sum of RF, Core and LDO currents.
                3. In sleep, this should be ~30uA,
                4. In pause ~1mA,
                5. In CPU active ~3mA,
                6. And during RF activity ~22mA.


                To measure I/O Current:

                1. Remove 0 Ohm R8 and measure across this.
                2. If all IO is input and output disabled then:
                3. This will be leakage of a few hundred uA when active,
                4. A few uA when sleeping,
                5. And ~1.5uA in deep sleep without timed wake.


                BCM20732 TAG002 Board:

                1. LDO in current should be measured by removing Rd1 from position BC and measuring current through position BC.
                2. For the IO current, remove R8 and measure current across the terminals of R8.


                Let us know if this answers your questions.



                • 5. Re: Power consumption

                  Thank you. I will give this a try and get back to you.

                  • 6. Re: Power consumption

                    I have read BCM20732S datasheet, its table-5 told me that transmission current is 9.3mA, why is "during RF activity ~22mA."?

                    • 7. Re: Power consumption

                      Not sure of the context under which that value is provided.


                      For now, the following table 5 values within the datasheet should be used when making power calculations.


                      We are also working on publishing more detailed power values (with use cases)