What uses most power in Ebook-reader aps.?

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posted
15 years ago

Sat, Jul 26, 2008 4:40 PM

I've had this pocket calculator to 10 to 20 years: marked "2 penlight..for over 22,00 hours of continuous use, -- auto shut off".

It's use for a few minutes, about 10 times a year. I replace the AAs approx after 2 years. I think it's got a [originally Fairchild of '70] F8 u-proc. inside.

Q. It must be [partially] live all the time, to read the on-key, or can a single CMOS gate acheive this ?

Q. In general what takes the most power in a Ebook-reader which could display approx. 80 * 20 text chars ?

Q what technology display uses the least power for this pixel count ?

== TIA.

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posted
15 years ago

Sat, Jul 26, 2008 5:08 PM

My 20 year old Sharp calculator still runs on its original 2 coin cells...

The circuit doesn't have to be active (scanning the keyboard), one could devise a circuit that doesn't use any power until the "on" key is pressed

I guess that depends on the e-book reader, how many times you change pages...etc.

ePaper or eInkt only use power when the contents are changed. Also quality wise these display technologies are impressive, it is very much like reading text from real paper. Unfortunately changing the contents is rather slow (about half a second).

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posted
15 years ago

Sun, Jul 27, 2008 5:34 AM

Dombo wrote:-

OK.

I don't think you can have an open-circuit across the power rails, unless you consider a solidstate switch as being OC, since we can't use relays. But why not just use a plain toggle switch !?

Yes ePaper or eInkt are apparently used for Ebooks. Is it expensive/reliable compared to normal black & white LCD ? How much power does normal black & white LCD use when static and when re-writing ?

Thanks,

== Chris Glur.