Baseline Power Consumption Benchmarking on nrf52dk

[federicoc]

Hello Nordic Forum,

I ran the Power Profiler Kit on an nRF52DK development board to establish a baseline power consumption.

The current firmware project is quite simple, and I have removed most of the GPIO, including UART, to minimize power consumption.

I have not enabled power management yet, as I am focusing on benchmarking the current power usage.

Currently, the kit reads about 23.25 mA while running in the main loop. Does this seem reasonable?

Would I expect to achieve a significant reduction in consumption if I enable Power Management, or would this only be beneficial when I add sensors that implement power management interfaces?

Thank you in advance for your knowledge and support.

Kind regards,

while (1) {

k_sleep(K_FOREVER);

}

CONFIG_CPP=y

CONFIG_GPIO=y

CONFIG_I2C=y

CONFIG_I2C_NRFX=y

CONFIG_CBPRINTF_FP_SUPPORT=y

CONFIG_DEBUG=y

CONFIG_PRINTK=y

CONFIG_LOG=y

[Vidar Berg]

Hello,

The RTOS scheduler enters the IDLE thread when there is no work to do and puts the chip into sleep mode (System ON). In this state, the system run current should be only a couple of microamps provided no peripherals are active during sleep that keep the HF clock running. This is also the floor current you should expect to measure with most SDK samples when UART is disabled (set CONFIG_SERIAL=n in your project configuration). With UART enabled for logging, you may measure around 600 uA.

Currently, the kit reads about 23.25 mA while running in the main loop. Does this seem reasonable?

This is way more than what you should expect to see. Unless you are using GPIO outputs to drive external loads, the chip itself should never draw this much current. Does your measurement setup match what I described in this post here: /f/nordic-q-a/120743/ble-advertising-power-benchmark/532498?

Best regards,

Vidar

[federicoc]

Thank you Vidar, 

after reviewing the post, I noticed that to measure the current in source meter mode I had to cut SB9 bridge and use two USB cables as detailed in 

https://docs.nordicsemi.com/bundle/ug_ppk2/page/UG/ppk/measure_current_source_meter.html.


Now I am measuring 9.14 nA of floor current, which seems more in line with your data, but very low considering that it should average at around 300 nA from specs

[Vidar Berg]

This is closer to expected results, but I am afraid the measurement is too low now to be valid. Did you use the same supply voltage as I did in the other post? It is important that it matches the VDD (~2.9V) on the board to avoid leakage from the USB supply.

[federicoc]

I agree Vidar, 

something is off, and probably is my nrf52DK.

My understanding is that I should be able to configure Source Measurement as displayed in this video (min 6: 13) and use the ppk as external power supply:
https://www.youtube.com/watch?v=B42lPvkUSoc

and/ following the following links:

https://docs.nordicsemi.com/bundle/ug_ppk2/page/UG/ppk/measure_current_source_meter.html

https://docs.nordicsemi.com/bundle/ug_nrf52832_dk/page/UG/dk/prepare_board.html

In Source Measurement, if is the ppk to supply voltage, I would need to solder SB12.

Now, in my case supplying the voltage to the ppk without the USB connected via the External Supply pins does not work even after soldering SB12.

It seems that the only way I get power to the chip is by connecting the USB from the nrf52dk to the PC. 

 

[Vidar Berg]

The configuration I showed is only supplying the nRF on chip on P22, and with this configuration, the USB should remain connected to supply the interface MCU and LEDs.

[federicoc]

Ok, so the configuration of board, ppk and wiring seems correct.
I still struggle to understand how with everything disabled in
prj.conf and overlay file and a code that only flashes an led on and off on the nrf52dk (pin 20), i read a current of 160uA when led is off.
Is there a sample that has everything turned off and power mode configured for the lowest possible consumption that I can use for reference?

Thank you

CONFIG_CPP=y

CONFIG_GPIO=y

CONFIG_SERIAL=n

CONFIG_PM_DEVICE=y

&uart0 {

status = "disabled";

};

&pwm0 {

status = "disabled";

};

&bprot {

status = "disabled";

};

&ccm {

status = "disabled";

};

&ecb {

status = "disabled";

};

&ficr {

status = "disabled";

};

&gpiote {

status = "okay";

};

&egu0 {

status = "disabled";

};

&power {

status = "disabled";

};

&reg {

status = "disabled";

};

&egu1 {

status = "disabled";

};

&egu2 {

status = "disabled";

};

&egu3 {

status = "disabled";

};

&egu4 {

status = "disabled";

};

&egu5 {

status = "disabled";

};

&rng {

status = "disabled";

};

&ppi {

status = "okay";

};

&nvic {

status = "disabled";

};

&clock {

status = "okay";

};

&uicr {

status = "disabled";

};

&mwu {

status = "disabled";

};

&wdt {

status = "disabled";

};