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why large current?

dsp999
Expert 1495 points
Other Parts Discussed in Thread: CC2541, CC2640

we have a project, with power saving, running on a board, everything is ok, current is 0.5mA at bluetooth advertising, and 1uA when sleep.

but, exactly the same project, run on another board, which is more simple, no IO is connected, but current is strange 7-10mA at first, then go to sleep 1uA.

we have tried all IO setting, including set it IO, input with pull up/pull down, or 3-state, or out, nothing help.

our project has no iic or uart work.  

why?  should not be board problem as we tested several (at least five) boards

help!

  • 0
    TI__Guru 56590 points
    Hello dsp,
    how are you measuring the current?
    Also refer to the documents I listed in a reply to your other thread:
    e2e.ti.com/.../467859
  • 0 in reply to Eirik V
    Expert 1495 points

    use a meter in power supply, I am pretty sure the current measurement is right, it is obvious large current.

    so I am still stuck in this problem.

  • 0 in reply to dsp999
    TI__Guru 56590 points

    Hello dsp,

    Which chip are you using? 

    Both the CC2541 and the CC2640 will use more than 0.5mA during active TX/RX modes. Read the documents I listed. Your current meter might not be accurate/fast enough to measure the fast current fluctuations during BLE broadcast events. 1 uA during sleep is correct and most current meters will be able to measure this as it is stable over a longer period of time.

  • 0 in reply to Eirik V
    Expert 1495 points
    cc2541. uart disable. current measurement suppose correct because we did the same and get correct result for another board, difference of these two boards is, one has a sensor, one without sensor, the one without sensor has strange large current 10mA. no matter how I set the IO.
  • 0 in reply to dsp999
    TI__Guru 56590 points
    dsp,
    Is this a continuous current?
    What do you mean by "but current is strange 7-10mA at first"? What, how and when are you measuring?
    Can you share your schematic?

    From the CC2541 user guide:
    7.1 Unused I/O Pins
    Unused I/O pins should have a defined level and not be left floating. One way to do this is to leave the pin
    unconnected and configure the pin as a general-purpose I/O input with pullup resistor. This is also the
    state of all pins during and after reset (except P1.0 and P1.1, which do not have pullup/pulldown
    capability). Alternatively, the pin can be configured as a general-purpose I/O output. In either case, the pin
    should not be connected directly to VDD or GND, in order to avoid excessive power consumption.
  • 0 in reply to Eirik V
    Expert 1495 points
    yes continuous stable current.
    on board B, 7-10mA at power on, go to sleep in 5 seconds if not start "start device event", will not go to sleep if start this event.
    but will go to sleep although start this event on Board A, no event is running after 10s, we set advertising 10s, then stop advertising.
    today a new case, on board A, after execute a SetSleep function in which I stop/clear all events, only start a new long time event, check something after 10s. we see current goes to 0 after SetSleep. then go to 8mA after 10s, then keep 8mA, no change.

    have read about IO you said. have tried different setting, not solved the question.
    there must be something we missed.
  • 0 in reply to dsp999
    Prodigy 10 points

    Hellp dsp,

    have you solved the current issue, it seems I have met the same one.

    thanks.