static power during advertising with nRF52832

[Reza papi]

Hi everyone,

I am using nRF52832 DK to transmit data to another development kit. During advertising, I measure the current with PPK II and see that the DK draws a static current of nearly 8mA. I expect to current goes down to a few micro amp between each advertisement but it did not happen. After transmitting data the DK goes to idle mode and draws only 7 uA which I believe is reasonable. Could you please help me with this issue?

This is the measured current during advertising.

 

The second photo shows the measured current during idle mode.

Thank you, guys.

[Simonr]

Hi

Are you running the PPK 2 in Source or Ampere mode here? Can you show me how the PPK and nRF52 DK are connected? From the IDLE mode it seems correct, even though some of those noise spikes are very high. 

The base current of ~7mA is very high indeed, so either there must be something incorrect with your setup, or the radio is running constantly in your application. What application do you have running on the nRF52832 DK? Is it based on any of the projects in either of our SDKs?

Best regards,

Simon

[Reza papi]

Hi Simonr,

I am using PPK 2 in Amper mode. I modified the BLE UART code to transmit an array of data every 1 minute. So there is an RTC timer in the application that every minute causes an interruption and turns on the radio to send the packet of data. the code works to transmit the packet for the first time but when RTC wakes nRF up to send for the second time there is some error with it. But the power consumption that I showed was for the first transmission.

Here is my test setup. For the measurement, I cut SB9 and short SB11 with a screwdriver during measurement. Thank you

  

[Simonr]

Hi

I'm not sure how great of an idea it is to use a screwdriver for shorting like that. Can you also test to see if you get the same current consumption by powering the DK "normally" with a micro USB? Ampere mode is recommended, and seems to be connected correctly. You can remove the bottom GND cable that you've connected to the + side on the External supply header though, as it serves no purpose.

As you can see the floor current of the basic ble_app_uart example shouldn't draw much more than 1.2mA by default, and there should still be room for improving the current consumption I think. Please check out my colleague's guide on current consumption here, which you can check out to see if there is something you can do to your example project.

Best regards,

Simon

[Reza papi]

Hi,

Thank you for your reply. I change the code and now it seems the power consumption is reasonable. Am I right?

but still, there are some spikes as you can see in the photo during advertising mode up to 18mA.

I have not activated DC/DC regulator in the code. I see some posts in the forum that suggest to active it to further reduce the current consumption. Could you please explain how this helps to minimize power consumption?

[Simonr]

Hi

The current consumption seems much more reasonable now indeed. Glad to seee that. The spikes you're seeing are caused by the PPK when it switches to a smaller measurement resistor because of the sudden current increase. Unfortunately, the firmware doesn't filter these out as well as we would like. These won't affect the average current consumption, so it's not anything to worry about, but it will make measuring the max. current consumption harder to determine.

Best regards,

Simon