Profiling Current/Voltage/Temperature

[Pranay Kotasthane]

Hi All,

I wanted to profile a use case in terms of the current/voltage/
temperature. I have the panda build for android installed on the
board. I wanted to run a MP3 on the android OS and then measure the
following:

1. The current drawn from the power supply when the MP3 is playing.
Can I get an instantaneous value for this?

2. The voltage drop at all the three power supplies: IVA,MPU and CORE.

3. The temperature profile for the die as the MP3 is being played.

Is it possible to accomplish any of the above on Pandaboard. Kindly
suggest.

Thanks

[David Anders]

http://elinux.org/PandaBoard_Power_Measurements

On Jun 6, 1:24 am, Pranay Kotasthane <pranay.kotasth...@gmail.com>
wrote:

[Pranay Kotasthane]

Thanks David for the help.

I was looking for something more elementary. As I have Android running
on the pandaboard are there some files created on the fly that I can
read out to report the current/voltage drop etc.

For example I found that a file /sys/bus/platform/omap_hwtemp.0/
temperature keeps getting updated with the die temerature. But I could
not locate something similar for the voltage and current measurements

-Pranay

> > Thanks- Hide quoted text -
>
> - Show quoted text -

[David Anders]

Pranay,

i am afraid that is about as elementry as it gets for doing power/voltage monitoring on the panda....

Dave


On Thursday, June 7, 2012 5:36:07 AM UTC-5, Pranay Kotasthane wrote:

Thanks David for the help.

[David Anders]

VJ,

yes this is possible. i recommend using a INA219.

have a look at this short article that describes the difference
between low and high side current sensing:

http://www.eetimes.com/design/analog-design/4010355/Understand-low-side-vs-high-side-current-sensing

Dave


On Jul 12, 10:29 am, jvi...@gmail.com wrote:
> Hi Dave,
>
> Thanks for the article write-up. I am curious if it is possible to measure
> the power consumed by the A9 processor on the other side of the regulator.
> We want to eliminate the regulator inefficiency in our measurements, and
> simply look at the core power draw. This involves putting the sense
> resistor after the L23 inductor and C213 capacitor. Have you tried this? Is
> this even feasible on the pandaboard?
>
> vj.

[Aaron Carroll]

Hi VJ,

I've done that for a bunch of the SMPS outputs and it works great. 20
mohm
is about right for the higher power outputs, like MPU, CORE, etc.


-- Aaron

On 13 July, 01:29, jvi...@gmail.com wrote:
> Hi Dave,
>
> Thanks for the article write-up. I am curious if it is possible to measure
> the power consumed by the A9 processor on the other side of the regulator.
> We want to eliminate the regulator inefficiency in our measurements, and
> simply look at the core power draw. This involves putting the sense
> resistor after the L23 inductor and C213 capacitor. Have you tried this? Is
> this even feasible on the pandaboard?
>
> vj.
>
>
>
>
>
>
>
> On Thursday, June 7, 2012 11:02:32 AM UTC-5, David Anders wrote:
>

[Kiran Chandramohan]

Hello David,

Is it possible to make the measurements for current/power without inserting a sense resistor ? The vector fabrics article does not talk about inserting a sense resister. From what i have understood it talks about measuring power using the resistance of the inductors.

http://www.vectorfabrics.com/blog/item/power_consumption_omap4430_pandaboard

From the article what i see is that the power of only the A9s(using L18), IVA system(using L21) and the GPU(using L13) can be measured . The IVA consists of M3, DSP processors and other hardware accelerators. Is it possible to measure power consumption of the M3 processors on board separately from the DSP and other IVA accelerators ?

--Kiran