Reduce power consumption in LC3 driver.

[ChiragBhavsar]

Hi,

We are using the LC3 driver in our product.

We measured the current consumption with and without the LC3 driver.

When the LC3 driver is enabled, the current is 4.36 mA, while without the LC3 driver it is 3.43 mA.

How can we reduce this current?

Is there any macro or configuration available to optimise power consumption?

[Elfving]

Hi,

First of all, I feel forced to show for instance this, so that you know that there is a lot one could do in regards to power saving.

I can check if the relevant team has any suggestions, but first: Are you using NCS and SDC? What are you using when not using the LC3? Are you seeing any difference between different bitrates etc?

Regards,

Elfving

[ChiragBhavsar]

We tested current consumption by enabling and disabling LC3.

Our setup:

• Board: nRF5340 DK

• SDK: NCS v2.6.2

• Microphone: MMICT5837-00-012

• Interface: PDM

During mono audio capture over PDM, we observed a current draw of about 1.5 mA.

My questions are:

1. Is there any way to reduce this current consumption further?

2. How much current does the PDM peripheral itself typically draw in mono mode on the nRF5340 (excluding microphone current)?

[Elfving]

Could you expand a bit more how you are testing this? What are you doing in the scenarios when you are not using the LC3?

Regards,

Elfving

[ChiragBhavsar]

we just read the microphone data using PDM interface,we did not encode the data using the LC3

[Elfving]

ChiragBhavsar said:

we just read the microphone data using PDM interface,we did not encode the data using the LC3

Ah okay. I also see you've opened a new case here. When it comes to lowering the consumption of the LC3 codec I think using the different bitrates I mentioned earlier is the only go-to strategy.

When it comes to the PDM consumption, could you try the suggestion from my colleague there; trying this on a newer NCS version?

Regards,

Elfving

[Elfving]

Or what is the problem here exactly, the power (current) or total energy used? Bit and sample rate being reduced would atleast reduce encoding time ->More CPU idle time -> reduced power consumption. Though this would mainly come from the use of the I2S peripheral, and if you need to use I2S all the time, you may not observe too large overall difference from reducing encoding time.

Regards,

Elfving