Register Guidelines E-Books Search Today's Posts Mark Forums Read

Go Back   MobileRead Forums > E-Book Readers > Sony Reader > Sony Reader Dev Corner

Notices

Reply
 
Thread Tools Search this Thread
Old 01-26-2007, 06:53 AM   #1
rothe957
Ingenieur
rothe957 is on a distinguished road
 
rothe957's Avatar
 
Posts: 8
Karma: 65
Join Date: Nov 2006
Location: Berlin - Germany
Device: Sony PRS-500 / Hiebook / SonyEricsson P910i
Lightbulb PRS-500 power consumption measurements

I charged my PRS-500 today using a lab power supply.
The battery was empty (reader came up, said "LOW BATTERY", then "NO BATTERY", then shut off immediately).
After I found out that USB charging won't work without driver,
I used plan B: a power plug from a universal adapter set and a lab power supply. I set it to 5.20V, turned output on and the reader started charging right away at about 560mA. Now, about 2 hours later, current is down to 140mA.
I then switched the reader on, it showed the "starting up..." screen.
During startup it consumed about 140mA more than when it was off (and only charging).
As long as the unit is just sitting there and no buttons get pressed, there is little or no additional current consumption (less than 5mA, maybe zero; the accuracy of the ampmeter in the lab power supply does not allow for more precise measurements, sorry).
A page turn causes a short (<2s) increase in current consumption, with a peak of about 220mA.

So much for the raw data.

Now a few ballpark figure calculations just for fun:
Lets assume a page turn consumes 180mA for 2 seconds. This means 360mAs or 0.1mAh per page turn. Judging from the physical battery cell size, it has a capacity somewhere in the 800mAh range. At 0.1mAh per page turn, you would get 8000 page turns out of a full charge in a perfect world. Well, pretty close to the 7500 claimed by Sony, considering that these are just ballpark figures..

^_^
rothe957 is offline   Reply With Quote
Old 01-26-2007, 08:28 AM   #2
Alexander Turcic
Fully Converged
Alexander Turcic ought to be getting tired of karma fortunes by now.Alexander Turcic ought to be getting tired of karma fortunes by now.Alexander Turcic ought to be getting tired of karma fortunes by now.Alexander Turcic ought to be getting tired of karma fortunes by now.Alexander Turcic ought to be getting tired of karma fortunes by now.Alexander Turcic ought to be getting tired of karma fortunes by now.Alexander Turcic ought to be getting tired of karma fortunes by now.Alexander Turcic ought to be getting tired of karma fortunes by now.Alexander Turcic ought to be getting tired of karma fortunes by now.Alexander Turcic ought to be getting tired of karma fortunes by now.Alexander Turcic ought to be getting tired of karma fortunes by now.
 
Alexander Turcic's Avatar
 
Posts: 17,107
Karma: 10995944
Join Date: Oct 2002
Location: Switzerland
Device: Sony PRS-650 / Nexus 7 / Kindle PW
VERY interesting work!

It would be cool if you could test power consumption with books stored in internal memory vs. books stored in external memory such as an SD card. We have numerous reports that the latter uses considerably more power per page turn.
Alexander Turcic is offline   Reply With Quote
 
Enthusiast
Old 01-26-2007, 10:12 AM   #3
rothe957
Ingenieur
rothe957 is on a distinguished road
 
rothe957's Avatar
 
Posts: 8
Karma: 65
Join Date: Nov 2006
Location: Berlin - Germany
Device: Sony PRS-500 / Hiebook / SonyEricsson P910i
Quote:
Originally Posted by Alexander Turcic
It would be cool if you could test power consumption with books stored in internal memory vs. books stored in external memory such as an SD card. We have numerous reports that the latter uses considerably more power per page turn.
The measurements were taken with books in internal memory, no memory card inserted.
Hmm, unfortunately, I don't have a SD card or MemoryStick here now. I'll be able to test it next week thursday or friday.
From what I know about the usual current consumption of SD cards, I estimate a memory card would raise the page turn current by about 40-60mA.

Some more info: When charging was complete, current consumption from the lab power supply with a book page on the display was shown as zero (lab ps ampmeter, not sure if it was really zero, lets say: below 1mA). Page turn current peaked at about 220mA (drawn from external power supply, no mem card).
Varying the external supply voltage from 4.8V...5.2V didn't make a difference in current consumption.

^_^

Last edited by rothe957; 01-26-2007 at 10:15 AM.
rothe957 is offline   Reply With Quote
Old 01-26-2007, 11:18 AM   #4
NatCh
Gizmologist
NatCh ought to be getting tired of karma fortunes by now.NatCh ought to be getting tired of karma fortunes by now.NatCh ought to be getting tired of karma fortunes by now.NatCh ought to be getting tired of karma fortunes by now.NatCh ought to be getting tired of karma fortunes by now.NatCh ought to be getting tired of karma fortunes by now.NatCh ought to be getting tired of karma fortunes by now.NatCh ought to be getting tired of karma fortunes by now.NatCh ought to be getting tired of karma fortunes by now.NatCh ought to be getting tired of karma fortunes by now.NatCh ought to be getting tired of karma fortunes by now.
 
NatCh's Avatar
 
Posts: 11,605
Karma: 926222
Join Date: Jan 2006
Location: Republic of Texas Embassy at Jackson, TN
Device: Nook STGR
Very nice analysis, rothe957, very nice, indeed.
NatCh is offline   Reply With Quote
Old 01-26-2007, 11:21 AM   #5
TadW
Uebermensch
TadW ought to be getting tired of karma fortunes by now.TadW ought to be getting tired of karma fortunes by now.TadW ought to be getting tired of karma fortunes by now.TadW ought to be getting tired of karma fortunes by now.TadW ought to be getting tired of karma fortunes by now.TadW ought to be getting tired of karma fortunes by now.TadW ought to be getting tired of karma fortunes by now.TadW ought to be getting tired of karma fortunes by now.TadW ought to be getting tired of karma fortunes by now.TadW ought to be getting tired of karma fortunes by now.TadW ought to be getting tired of karma fortunes by now.
 
TadW's Avatar
 
Posts: 2,582
Karma: 1094606
Join Date: Jul 2003
Location: Italy
Device: Kindle
Quote:
Originally Posted by rothe957
Some more info: When charging was complete, current consumption from the lab power supply with a book page on the display was shown as zero (lab ps ampmeter, not sure if it was really zero, lets say: below 1mA). Page turn current peaked at about 220mA (drawn from external power supply, no mem card).
I guess page turn also varies depending on the complexity of the content.

Nice work, rothe!
TadW is offline   Reply With Quote
Old 01-26-2007, 11:22 AM   #6
Azayzel
Cache Ninja!
Azayzel ought to be getting tired of karma fortunes by now.Azayzel ought to be getting tired of karma fortunes by now.Azayzel ought to be getting tired of karma fortunes by now.Azayzel ought to be getting tired of karma fortunes by now.Azayzel ought to be getting tired of karma fortunes by now.Azayzel ought to be getting tired of karma fortunes by now.Azayzel ought to be getting tired of karma fortunes by now.Azayzel ought to be getting tired of karma fortunes by now.Azayzel ought to be getting tired of karma fortunes by now.Azayzel ought to be getting tired of karma fortunes by now.Azayzel ought to be getting tired of karma fortunes by now.
 
Azayzel's Avatar
 
Posts: 643
Karma: 1002300
Join Date: Jan 2007
Location: Tokyo, Japan
Device: PRS-500, HTC Shift, iPod Touch, iPaq 4150, TC1100, Panasonic WordsGear
This is a cool experiment, especially to give real-world numbers to corporate marketing claims. I too, would be interested in the power consumption using and SD card; hopefully you can find locally for ~$10 or so to test it out (could always pull one out of your digital camera or old-school MP3 player ;-) )

Thanks for informing us, 8k pages is friggin cool!
Azayzel is offline   Reply With Quote
Old 01-26-2007, 11:58 AM   #7
kovidgoyal
creator of calibre
kovidgoyal ought to be getting tired of karma fortunes by now.kovidgoyal ought to be getting tired of karma fortunes by now.kovidgoyal ought to be getting tired of karma fortunes by now.kovidgoyal ought to be getting tired of karma fortunes by now.kovidgoyal ought to be getting tired of karma fortunes by now.kovidgoyal ought to be getting tired of karma fortunes by now.kovidgoyal ought to be getting tired of karma fortunes by now.kovidgoyal ought to be getting tired of karma fortunes by now.kovidgoyal ought to be getting tired of karma fortunes by now.kovidgoyal ought to be getting tired of karma fortunes by now.kovidgoyal ought to be getting tired of karma fortunes by now.
 
kovidgoyal's Avatar
 
Posts: 25,916
Karma: 5035037
Join Date: Oct 2006
Location: Mumbai, India
Device: Various
You can charge it from USB without the driver. Just use linux and libprs500.
kovidgoyal is online now   Reply With Quote
Old 01-26-2007, 05:59 PM   #8
rothe957
Ingenieur
rothe957 is on a distinguished road
 
rothe957's Avatar
 
Posts: 8
Karma: 65
Join Date: Nov 2006
Location: Berlin - Germany
Device: Sony PRS-500 / Hiebook / SonyEricsson P910i
Quote:
Originally Posted by kovidgoyal
You can charge it from USB without the driver. Just use linux and libprs500.
Well, I admit that I consider installing the driver the easier way.
Compared to installing Linux and then getting and installing libprs500.
I have a few linux machines in my office/workshop, but these are all embedded non-x86 devices without USB.
No, as tempting as it sounds - I think I stick to the lab power supply, and try to remember to bring the Sony driver CD next time.

^_^
rothe957 is offline   Reply With Quote
Old 01-30-2007, 03:25 AM   #9
rothe957
Ingenieur
rothe957 is on a distinguished road
 
rothe957's Avatar
 
Posts: 8
Karma: 65
Join Date: Nov 2006
Location: Berlin - Germany
Device: Sony PRS-500 / Hiebook / SonyEricsson P910i
Lightbulb More detailed measurements

Well, I added a current sense resistor (1 Ohm) to the setup, and connected a scope.
X axis is time, 1 second per grid. Y axis is current, 100mA per grid.
The small "1->" marks the zero current line.
Screenshots were done the lotech way, with a camera.

First some measurements with files in internal memory:

Turning the reader on then off again, Baen RTF file, internal memory:


Page turn, Baen RTF file, internal memory:


Page turn, PDF file ('1984'), internal memory:



Next with files on SDcard (Sandisk 1GB):

Page turn, Baen RTF file, SDcard:


Another page turn, Baen RTF file, SDcard:


Page turn, PDF file (Atmel datasheet, with graphics), SDcard:



And another test set with a Sony MSmicro (512MB) with MS adapter:

Page turn, Baen RTF file, MSmicro:


Another page turn, Baen RTF file, MSmicro:


yet another page turn, Baen RTF file, MSmicro:


Page turn, PDF file (Atmel datasheet, with graphics), MSmicro:


RTF formatting + update of wait symbol, Baen RTF file, MSmicro:


Conclusions, anyone?

^_^
rothe957 is offline   Reply With Quote
Old 01-30-2007, 07:10 AM   #10
dstampe
dstampe
dstampe began at the beginning.
 
Posts: 50
Karma: 17
Join Date: Jan 2007
Location: Canada
Device: Sony PRS-500
The big spike followed by high consumption and noise is what I would expect from the eInk circuitry. This probably has a high-voltage DC-to-DC converter, followed by a matrix of drivers for row and column lines in the display.

This shows a big spike of current draw as it starts up and charges all its capacitors. Then the variable load producing the noise is a combination of this supply and the variable capacitive load as different lines in the eInk display are charged and discharged, Obviously this is a big user of power.

There seem to be 3 load levels. One is fairly low, probably the CPU coming out of sleep mode. The second appears to correspond to display preparation, as it's much longer for the PDF file display. Not sure if this is CPU use, display buffer being powered up, or flash memory access. The highest level seems to be when the eInk power supply is being used.

When used with external flash, the second level of current draw takes longer before the page display, so this second level probably does indicate internal or external flash memory access. (External flash access also appears to be much slower). Also, the CPU stays active for several seconds longer after a page update. So using external flash memory will shorten battery life by up to 40%, I would expect. Of cource, it looks like viewing complex PDF files is even more expensive.

Last edited by dstampe; 01-30-2007 at 07:14 AM.
dstampe is offline   Reply With Quote
Old 01-30-2007, 07:39 AM   #11
TadW
Uebermensch
TadW ought to be getting tired of karma fortunes by now.TadW ought to be getting tired of karma fortunes by now.TadW ought to be getting tired of karma fortunes by now.TadW ought to be getting tired of karma fortunes by now.TadW ought to be getting tired of karma fortunes by now.TadW ought to be getting tired of karma fortunes by now.TadW ought to be getting tired of karma fortunes by now.TadW ought to be getting tired of karma fortunes by now.TadW ought to be getting tired of karma fortunes by now.TadW ought to be getting tired of karma fortunes by now.TadW ought to be getting tired of karma fortunes by now.
 
TadW's Avatar
 
Posts: 2,582
Karma: 1094606
Join Date: Jul 2003
Location: Italy
Device: Kindle
So it's generally true to say that RTF is better than PDF in terms of battery life?
TadW is offline   Reply With Quote
Old 01-30-2007, 07:50 AM   #12
Azayzel
Cache Ninja!
Azayzel ought to be getting tired of karma fortunes by now.Azayzel ought to be getting tired of karma fortunes by now.Azayzel ought to be getting tired of karma fortunes by now.Azayzel ought to be getting tired of karma fortunes by now.Azayzel ought to be getting tired of karma fortunes by now.Azayzel ought to be getting tired of karma fortunes by now.Azayzel ought to be getting tired of karma fortunes by now.Azayzel ought to be getting tired of karma fortunes by now.Azayzel ought to be getting tired of karma fortunes by now.Azayzel ought to be getting tired of karma fortunes by now.Azayzel ought to be getting tired of karma fortunes by now.
 
Azayzel's Avatar
 
Posts: 643
Karma: 1002300
Join Date: Jan 2007
Location: Tokyo, Japan
Device: PRS-500, HTC Shift, iPod Touch, iPaq 4150, TC1100, Panasonic WordsGear
Hmm, wonder about the the BBeB format; especially for say a PDF that was converted using tools fromt this website? I'll post something you can test with here after it finishes transcoding. Didn't have any small PDF's already converted that I could u/l so you could test actual PDF vs. (hopefully) improved LRF. That is, of course, if you don't mind running the test with the samples I've provided.

Note: It's a freely available eZine converted from the distributed PDF to LRF using PDFRasterfarian v2.1.4.

Edit: Here are the files, thanks for posting your data!
Attached Files
File Type: rar INSECURE-Mag-1.(LRF).rar (1.94 MB, 229 views)
File Type: rar INSECURE-Mag-1.(PDF).part1.rar (4.77 MB, 231 views)
File Type: rar INSECURE-Mag-1.(PDF).part2.rar (1.15 MB, 209 views)

Last edited by Azayzel; 01-30-2007 at 08:00 AM. Reason: Here are the files mentioned previously.
Azayzel is offline   Reply With Quote
Old 01-30-2007, 07:57 AM   #13
rothe957
Ingenieur
rothe957 is on a distinguished road
 
rothe957's Avatar
 
Posts: 8
Karma: 65
Join Date: Nov 2006
Location: Berlin - Germany
Device: Sony PRS-500 / Hiebook / SonyEricsson P910i
Quote:
Originally Posted by Azayzel
That is, of course, if you don't mind running the test with the samples I've provided.
I'll see what i can do. It might be a while until I have access to the scope again, though. Please be patient.

Quote:
Originally Posted by TadW
So it's generally true to say that RTF is better than PDF in terms of battery life?
I think it depends more on complexity. RTF is formatted text only. Formatted text in a PDF (see '1984' example) doesn't seem much different in terms of rendering time. A complex PDF with graphics etc. takes longer to render and thus needs more power per page turn.


^_^
rothe957 is offline   Reply With Quote
Old 01-30-2007, 08:48 AM   #14
scotty1024
Banned
scotty1024 is no ebook tyro.scotty1024 is no ebook tyro.scotty1024 is no ebook tyro.scotty1024 is no ebook tyro.scotty1024 is no ebook tyro.scotty1024 is no ebook tyro.scotty1024 is no ebook tyro.scotty1024 is no ebook tyro.scotty1024 is no ebook tyro.scotty1024 is no ebook tyro.
 
Posts: 1,300
Karma: 1479
Join Date: Jul 2006
Location: Peoples Republic of Washington
Device: Reader / iPhone / Librie / Kindle
Quote:
Originally Posted by dstampe
This shows a big spike of current draw as it starts up and charges all its capacitors. Then the variable load producing the noise is a combination of this supply and the variable capacitive load as different lines in the eInk display are charged and discharged, Obviously this is a big user of power.
I agree on all points but one: that spike is the inductor in the eink DC-DC convertor being charged.
scotty1024 is offline   Reply With Quote
Old 01-30-2007, 04:56 PM   #15
dstampe
dstampe
dstampe began at the beginning.
 
Posts: 50
Karma: 17
Join Date: Jan 2007
Location: Canada
Device: Sony PRS-500
Quote:
Originally Posted by scotty1024
I agree on all points but one: that spike is the inductor in the eink DC-DC convertor being charged.
I guess it depends on the power supply design. When I'm designing circuitry like this, I tend to go overboard on capacitors for the output of the power supply to reduce EMI and improve requlation, so it can take a LOT of current at startup to charge these. On the other hand, most DC-DC boost converters for applications like this where size and weight are an issue would use very high frequencies (>500 KHz) and extremely small inductors, so these might not store much energy.

Anyway, I presume Sony took some care to get high efficiency from the converter, so most of the load can be assumed to be unavoidable given the voltage requirements and capacitance of the eInk display. Hopefully the evolution of these displays will reduce the voltage and increase the contrast as well.

It also looks like the display uses less than 40% of the total for most updates, so this may already be at the point of diminishing returns, Less time spend running the CPU and reading the flash would seem more likel;y to pay dividends.
dstampe is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
PRS-600 e-Ink Power Consumption bakura82 Sony Reader 12 03-01-2010 10:19 PM
PRS-500 upgrade power AprilHare Sony Reader 26 02-09-2010 10:47 PM
Power for Sony 500 ebook Cecily Introduce Yourself 2 09-28-2009 10:08 AM
PRS-700 and PRS-505 Review and Comparison from a PRS-500 owner geekmeetsworld Sony Reader 5 03-01-2009 03:34 PM
Power consumption woes dyspepsic Sony Reader 43 06-14-2007 03:37 PM


All times are GMT -4. The time now is 08:03 AM.


MobileRead.com is a privately owned, operated and funded community.