Power consumption for NRF52832 SoftDevice v3.0.0

[kenearl]

Hi,

My apology if this question has been answered. I wonder if >2mA current draw for an APP with the following design considered normal consumption?

1. Custom GATT profile
2. Device Information Service profile
3. Advertising at 375ms
4. Power_manage() => Verified that the device goes to lp mode since my current draw was much higher when I commented out this function.
5. 3 additional software timer enabled
6. Power cycled to get out of debugging mode
7. Compilation optimised (-O3) and "Optimise for Time"

I still have other peripherals, e.g. SPI, TWI, GPIOTE, UART, which I have disabled for now to check the base current consumption with BLE on.

[Stian Røed Hafskjold]

Hi,

No, >2mA is not normal for this application. You can check the power calculator to see what is expected: devzone.nordicsemi.com/.../ 375ms advertising with full payload should give about 39µA.

In order to debug this we need some more information.

• How are you measuring current? P22 on DK, custom board, equipment etc.
• If you can post a hex file of your project I can do some measurements here.
• Have you tried just programming a unmodified example from the SDK to see if the current consumption is looking OK?
• Have you tried to put the chip to system OFF to get the base current/DC offset?

[kenearl]

Hi Stian,

Thanks for the info and feedbacks. The power profiler is a neat tool.

Please find my reply to your questions.

1. I am measuring it via the current measurement pins on the PCA10040 DK. Just to clarify with you, since the pins connect VDD to VDD_nrf, it only measures the current consumption on the nordic MCU right? If I attach other devices on the VDD, would it affect the measurement?
2. I haven't had the chance to get to my lab but I will pass it to you asap for testing. Thanks!
3. I have not test current consumption using an unmodified example but I did put the device to system OFF to get the base current which is in uA range but I can't remember the exact value atm.

[kenearl]

Hi Stian,

I have PM you the link to download my hex file. Thanks.

Also, I have performed some new testings on the DK version v1.1.0. Turns out that during my previous test, my colleague has handed me a damaged much older version of the DK. Anyway, the new current consumption is now around ~200uA, still not quite the 39uA you have mentioned. Perhaps you could look at my hex file for more info.

Appreciate your kind assistance, and if you could clarify my doubts in my previous comment. It would be great too!

[Stian Røed Hafskjold]

The current plot looks pretty normal. I get 270µA in average. This consists of:

• Base current of 1µA. Which is System On IDLE (power_manage())
• An application timer (RTC) that wakes up the chip every 1ms. I don't know what the chip is doing every 1ms, but this consumes about 220 µA in average. I guess this is what you see on your measurements.
• The BLE event consumes 50µA in average. I can see that you are not enabling DCDC. Enabling this (if you have DCDC components) will probably reduce the current to about 30-40µA depending on payload.

[kenearl]

Very much appreciate your help. Good to know it's normal to get 270uA. Also I woke the MCU up at 1ms to count the uptime in ms. Good to know that would result in ~220uA. Thank you.