No Backlighting

Peter Cyriax

• December 17, 2015 09:07

Hi,

I'm planning to run a Hight Brightness display via a NHD-4.3-480272MF-34 controller using a 12v battery power source. That means I'd have to jump through all sorts of hoops to get  24 v  for the backlighting.

So what happens it I just ignore the backlighting?

1. Will the display still work?
2. Will I simply get a black background?
3. Provided I use bright colours for the foreground colours will the display still be readable?


Thanks



Peter

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  Saurabh_B

  • December 17, 2015 10:07

  Peter,
  
  You will not be able to see anything on the display without the backlight. For TFT displays the backlight is a requirement.
  
  The NHD-4.3-480272MF-34 controller board does have a voltage booster circuit, but the original circuit was designed to operate with the NHD-4.3-480272EF-ATXL# (Standard brightness display)
  
  There is an option to power the backlight using your current board, but it will require some modification to the controller board.
  
  1. You will need to replace the LED Driver on the controller board. This will be labeled U2, it is located right above the 40 pos FFC Connector for the display.
      I recommend using a FAN5333BSX
  
  2. You will need to swap the resistor on R45 with another resistor that is roughly ~7.8 Ω.
  
  The LED driver will be able to produce the required voltage after these changes are made with a 3.3V input.
  
  

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  Peter Cyriax

  • December 17, 2015 11:07

  Hi Saurabh,
  
  That looks quite straightforward in principal, though where my old fingures are ateady enough for such a delicate operation is another matter. We'll see - thanks.
  
  
  
  
  
  Peter

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  Peter Cyriax

  • December 18, 2015 11:07

  Hi,
  
  
  In the short term, just to get things up and running, I can rig up any voltage I want (within reason), and I'd much prefer that route until I have the controller + display actually working.
  
  So:
   1. Can an unmodified  NHD-4.3-480272MF-34 control a NHD-4.3-480272EF-ASXN#-T or NHD-4.3-480272EF-ASXV# display (I have one of each)?
   2. If so, what do I have to do to make it work? Possibly apply a different voltage to pin the of the J3 connector?
   3. If not, do you have an alternative controller that can (without user modification) controll these screens
  
  Also... what power rating is required for the 7.8 Ohm resistor?
  
  
  Thanks
  
  
  
  Peter

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  Paul_B

  • December 18, 2015 13:07

  Hi Peter,
  
  Please see the information below:
  
  Digi-Key Part Number   RHM7.87CICT-ND
  7.87 OHM  1/8W 0805
  
  Hope this helps!

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  Peter Cyriax

  • December 18, 2015 14:07

  Hi Paul,
  
  
  Thanks... I've ordered that.
  
  
  But I'm still very worried that I may damage the controller while trying to replace those components.
  
  Do you make a controller that will drive these High Brightness/Sunlight readable sisplays without user modificataion?
  
  
  
  Cheers
  
  
  
  
  Peter

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  Paul_B

  • December 21, 2015 14:07

  Morning Peter,
  
  We are in the process of offering a controller board which will support our Sunlight Readable and Premium 4.3" TFT displays. This will be available to our customers in a couple weeks.
  
  In the short term, just to get things up and running you can make the modifications listed above or hold off until these new controller boards are released  

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  Peter Cyriax

  • December 28, 2015 14:07

  Hi,
  
  Sounds like good news. In the meantime I've ordered the components to try to make those modes.
  
  
  Happy Christmas
  
  
  Peter

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