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current and power measurement for nrf51822 (using evaluation kit)

Hello all, I want to do current measurement for nrf51822 which is flashed with my own ble application which uses some custom services. As mentioned in evaluation kit user guide i cut the SB8(solder bridge) and measured the current using multimeter. But i couldn't get meaningful readings(0 mA). Also my device disconnects as soon as it connects with peer client. Does anyone has any idea how to measure current?

Can i use power_profiling application of nrf6310 for PCA10001 for current and power measurement with some modifications?

There is similar question regarding current measurement. I also had a doubt whether it is normal that after cutting SB8 our chip is still working when connected to USB port?

  • Is it necessary to disable leds in order to measure current and power accurately(I want measure power consumption in advertising mode and at the time of data transmission )

  • Hi

    You can easily run the power profiling example on your evaluation kit even though it is made for the development kit. The only thing you need to do is to remap buttons and leds to the evaluation board. Do that by defining BOARD_PCA10001 in KEIL constant definitions, instead of the BOARD_NRF6310 constant, see the following image.

    C:\fakepath\Capture - Define the constant for the development kit in Keil Target Options.JPG

    On my multimeter, which does not have auto-range feature, I need to set it to measure mA range when I startup the program, as the chip draws a few milliamperes during startup, then when I enter low power state, it will show 0.00mA as the current is in the uA range. Then I must configure the meter to measure microamperes, then I will get a reading.

    Measure current consumption with a multimeter during advertising can be tricky as the advertising is periodic, creating spikes in the current consumption, and the multimeter might not display a definite reading. It would be better to have a oscilloscope to see an image instance of the current consumption. I have however successfully measured current consumption between advertising events with a multimeter, just by making the advertising interval long enough (a few seconds) so the multimeter has a chance to stabilize and display a reading between advertising events.

    There are also a few simple examples here to measure current consumption, that is perhaps interesting for you to try.

    Each led consumes around 0.5mA when lid, so disable all leds when measure current.

  • Thanks a lot Stefan! I am using method1(from eval-it user guide) for current measurement. As mentioned in my question after cutting SB8 i am still getting 0mA or 0uA. Is the current measurement is possible when my board is powered with USB or should I use battery and then measure the current? Please help!

  • The current measurements should work, independent if your supply to the board is via USB, external power supply or battery. Are you sure the SB8 solder-bridge is fully cut? What version of the evaluation board do you have?