Help in finding LCD display

Discussion in 'Embedded Systems and Microcontrollers' started by hemnath, Feb 22, 2013.

  1. hemnath

    Thread Starter New Member

    Dec 12, 2012
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    I'm designing a system where it consumes 3mA. I have to put something on the display. But the problem is, i cannot feed so much current.
    Is there any LCD with backlight that consumes less than 1 mA?
    I have searched a lot, but could not find any. If any one have come across. Please help.

    Thanks in advance :)
     
  2. takao21203

    Distinguished Member

    Apr 28, 2012
    3,577
    463
    Yes a static LCD with a pulsed high efficiency LED. What do you need to display?

    Less than 1mA is not much, but enough to pulse a high-efficiency LED at low currents.

    You may need to remove the reflector, or to use a diffusor. Green has the best efficiency. Not a french green 20mA LED, you need a clear ocean green LED. these have 18000 mcd at 20mA, still enough for a small LCD at 1mA average or even less.

    With an active LCD, I see little chance.
     
  3. hemnath

    Thread Starter New Member

    Dec 12, 2012
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    you mean Static LCD means, 3 1/2 digit LCD .. like that?
    I want to display "80.00 BAR" in display. With the static LCD, only numbers can be display. I want to display numbers with string.
    Or Is there any LED which consumes less than 1mA. So that i can keep a led on top of the "LCD without backlight display" to make the characters visible even in dark.
     
  4. takao21203

    Distinguished Member

    Apr 28, 2012
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    Yes as I say a 18000 mcd ocean green LED will be good for 1mA.

    There are more static LCDs, some even alphanumeric starburst, some small 3 digit, etc. Can be custom made as well.

    The LCD bias for character LCD is is no way optimized for ultra low current I think.

    What's your system voltage?
     
  5. hemnath

    Thread Starter New Member

    Dec 12, 2012
    20
    0
    My System voltage will be around +5V.
    Can you send me the link where can i find the datasheet for 18000 mcd ocean green LED?

    I have surfed but could not find. I got only " 5mm 10,000 mcd super bright ocean green LED" and i looked into that datasheet, Forward current is 25mA, which is very large in my case.

    Please help!!!
     
  6. takao21203

    Distinguished Member

    Apr 28, 2012
    3,577
    463
    Still bright enough. You don't have to run them at 25 mA.

    Or if you use a controller, you can modulate them so you don't waste so much in the resistor.

    You can also try to run your LCD at lower voltage. The backplane needs a little more voltage if you for instance run it at 3v, and the interface is much slower.

    If you only use 3v you even need a charge pump (not exactly power saving).
     
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