current Reading on BLE_POWER_PROFILING APP

[nirmal@nordic]

Hi, Everyone,

I am trying to achieve minimum current level, I can possibly achieve, with continuous BLE transmission

so, I tried running BLE_POWER_PROFILING_APP given by Nordic as an Example.... Though , I Wanted to ask you what is the current reading that I should get when BLE is transmittitng ..??

I am getting something around 0.040 mA when BLE is transmitting with 1000 ms Interval and 180 Second Timeout period, and Radio Tx Power set to -12 dBm in Connectable adv mode...

Can I achieve Lower than this ???

Without changing Tx Power or Interval ????

I am running S130 with SDK v 11.0.0-2-alpha

Thank you...

[Stian Røed Hafskjold]

Well, this depends on several parameters. In addition to BLE interval and TX power as you mention, the voltage, DCDC on/off and BLE payload also affects the power consumption. And of course, advertising mode vs. connection mode gives different currents.

I can give you a couple of examples with expected current consumption for advertising and connection with different payload. I am assuming the voltage is 3V and TX power is -12dB.

      TX payload	DCDC off	DCDC on

Adv 1000 ms:
      8 Bytes	    21uA		15uA (11uA)
      31 Bytes	    25uA		18uA (14uA)

Con 1000 ms:
      0 Bytes	    20uA		13uA (6uA)
      27 Bytes	    22uA		15uA (8uA)

These numbers are for the nRF51. I included numbers for nRF52 in the parentheses for reference.

[nirmal@nordic]

Thank you Stian...

@stian

But I don't get current less than 0.037 mA in Advertising mode with Adv Interval of 1000ms and 31 Bytes data with DC-DC Enable using NRF51 DEV kit...

Can you suggest me something else I should check ???

I am more of interested in getting current to somewhat around 0.026 mA range, so that with 1000mAh battery, It can survive longer.... When I increase Adv interval to 2000 ms, current goes to 0.025 mA.. but I need Lower Adv interval ....

[Stian Røed Hafskjold]

So what equipment are you using to measure current? Are you using an external power supply, or the USB power? And what voltage are you using?

[nirmal@nordic]

Hi, @Stian,

Thank you once again for your support.

I am using FLUKE 289 Multimeter to measure current. To measure the current , I program the chip with BLE_POWER_PROFILING application. and restart Dev kit and remove usb cable. .... so it is using 3V battery....given in NRF51 Dev kit....

and when I put multimeter in series with P22 as per NRF user guide... I get 0.037 mA current with 1000ms adv interval transmitting 31 Bytes.

One more thing @Stian : What should be the value of APP_ADV_INTERVAL for 1000 ms advertisement interval ??

should it be 1000 or 1600(0x0640), as it gets multiplied by 0.625... It is little ambiguous...

[Stian Røed Hafskjold]

Can you put the chip in System OFF mode and measure the current? NRF_POWER->SYSTEMOFF=1

You should get around 1uA. Just to see if the accuracy of your equipment is good enough, and that you don't have any leakage currents going anywhere.

APP_ADV_INTERVAL should be set to 1000 if you are using the MSEC_TO_UNITS macro. Like this: MSEC_TO_UNITS(1000, UNIT_0_625_MS)