Softdevice - basic BLE advertising current consumption.

RE: Softdevice - basic BLE advertising current consumption.

Karl Ylvisaker — Wed, 02 Mar 2022 10:29:46 GMT

[quote user="Neeraj Dhekale"]Currently, I am measuring current from a multimeter.[/quote]

Multimeters measures with a lot of averaging, which is likely why you are seeing 50 µA.
As you can see from the sleep mode documentation the SYSTEM_ON sleep current should be much lower - but the advertising events will cause quite an increase in consumption.
If you input your advertising configuration into the online power profiler you can subtract that from from your current measurement to estimate what your sleep current is, roughly.

[quote user="Neeraj Dhekale"]Do you mean that nrf_pwr_mgmt is optional and it goes into SYSTEM_ON sleep mode automatically whenever it is idle like Low power mode in Zephyr does?[/quote]

This is not the case, if you have not implemented system on sleep the device will not sleep and thus the CPU will be active all the time. It is not the same as the low power mode in Zephyr.

[quote user="Neeraj Dhekale"]Anyways I need to test in it power profiler. I will give a more clear idea about the difference before/after using nrf_pwr_mgmt.[/quote]

I agree - this would be the best way to get an accurate picture of the consumption during the different stages of your program.

Best regards,
Karl

RE: Softdevice - basic BLE advertising current consumption.

Neeraj Dhekale — Wed, 02 Mar 2022 10:08:42 GMT

Hello Karl Ylvisaker

Currently, I am measuring current from a multimeter.

[quote userid="87869" url="~/f/nordic-q-a/85332/softdevice---basic-ble-advertising-current-consumption/355736#355736"]the device will setup and start advertising, and then go into SYSTEM_ON sleep whenever it is not handling an incoming event.[/quote][quote userid="87869" url="~/f/nordic-q-a/85332/softdevice---basic-ble-advertising-current-consumption/355736#355736"]~50 µA average sounds like you are entering the SYSTEM_ON sleep successfully[/quote]

Without implementing nrf_pwr_mgmt code I was getting the same ~50 µA current consumption. I was expecting it will be less than this. Do you mean that nrf_pwr_mgmt is optional and it goes into SYSTEM_ON sleep mode automatically whenever it is idle like Low power mode in Zephyr does?

Anyways I need to test in it power profiler. I will give a more clear idea about the difference before/after using nrf_pwr_mgmt.

Thanks and regards,

Neeraj Dhekale

RE: Softdevice - basic BLE advertising current consumption.

Karl Ylvisaker — Wed, 02 Mar 2022 09:07:37 GMT

Hello Neeraj Dhekale,

[quote user=""]Am I doing anything wrong? Is the above code is enough to achieve low power mode?[/quote]

No, this looks alright - the device will setup and start advertising, and then go into SYSTEM_ON sleep whenever it is not handling an incoming event.

[quote user=""]but after using nrf_pwr_mgmt I don't see any change in current consumption.[/quote]

You should see quite the increase in power consumption if you measure it without idle_state_handle() running in the main loop.

[quote user=""]I can see the current consumption is ~50uA but after using nrf_pwr_mgmt I don't see any change in current consumption.[/quote]

~50 µA average sounds like you are entering the SYSTEM_ON sleep successfully - the radio events (advertisings, scan requests, connection requests) will happen periodically and wake the CPU and Radio peripheral, which will add to your average consumption - keep in mind that I do not know how your advertising is configured. You could use the Online Power Profiler to estimate how your advertising configuration will affect the power consumption of your device.

How are you measuring your power consumption by the way, are you using an oscilloscope, Power Profiler Kit, or other instrument?

Best regards,
Karl