QSB power

[TedMichon]

Does anyone have experience getting the power consumption of the QSB down?

Our application does not need any of the audio or video functionality.

At the LINUX prompt the board draws 380 to 500 mA from the 5V main supply. Thats about 2W to 2.5W.

The Freescale app note says that LINUX can draw about 160 mW while playing an MP3 file from SD,

Is there some low power demo code I can run and/or does anyone have experiene reducing the power consumption of the QSB?

Thanks.

-Ted

[DominicS]

Are you using ethernet? if not turn that off by removing ip=dhcp in uboot parameters.

Also, I would check if any update processes are running in the background, to pull kernel packages.

[PhilEndecott]

> turn off these leds? A soldering iron, surely....

[FernandoGinezd1]

I'm facing the same situation.
My system needs to be in standby (operating by batteries) during some days, and the power consuption is about 360mA (too high). Is there any command (or a driver to access the PMIC) to turn off these leds?
Thanks in advance!

[TedMichon]

Thanks Phil. As soon as we have some success building the kernel, we will remove the video as you suggest.

-Ted

[PhilEndecott]

(If your system is using a TV mode, rather than VGA, then it does cable detection, so simply removing the cable is enough to turn off at least the output drivers.)

[PhilEndecott]

To disable video, remove the video=mxc*** and tve stuff from the kernel command line.

[TedMichon]

If I knew how to disable these systems, then I would do so and then read the current. I'm just a hardware guy on this project.

(I was hoping someone had made some measurements and/or computations already.)

-Ted

[PhilEndecott]

> I'm more interested in what happens when the video and > audio stuff is disabled OK, try that then. What difference do you see?

[TedMichon]

OK, I now understand that cpufreq-info is LINUX command that will provide the current frequency/power trade off info, but I'm more interested in what happens when the video and audio stuff is disabled or removed and when the power supplies are designed more efficiently than in the QSB. How close can I get the 2W that the QSB boots up to in LINUX down to the 160 mW listed in the App note for just processing MP3 video from an SD card. That's a BIG gap!

-Ted

[TedMichon]

OK, I'm new to this. What is cpureq-info?

-Ted

[PhilEndecott]

What does cpufreq-info show?

[TedMichon]

Looks like there is 8 x (5.0-1.4)/470 x 5 = 306 mW just in the LEDs alone.

-Ted