Does the NHD-0216SZW display have a boost supply that needs to be enabled?

dfishman

• March 13, 2020 16:42

It seems to me that the OLED readout is a little dim. I tried to find out if there is a boost circuit by looking at the components on the rear of the display PWB. There is a coil, diode and cap. The voltage across the cap is 4.3V and the input voltage to the module is 5V.
If there is supposed to be a boost circuit, it apparently isn't working or not enabled.

can someone shed some light on this?

thanks

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  dfishman

  • March 23, 2020 21:33

  Additional information.
  
  I asked about the OLED boost display since it appears that my display is rather dim.
  It turns out that Pin 3 of the 16 pin interface was connected to resistor to ground.
  Could this have caused damage to the boost circuit?

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  Alee_S

  • March 24, 2020 08:30

  Hi dfishman,
  
  There is a boost circuit on the PCB to properly drive the OLED glass voltage which would be driven by your input of 5V.
  Pin 3 is also labelled as a N/C, so it can either be left unconnected or tied to GND.
  
  Are you able to share any pictures of the display powered up and appearing dim? Is it a uniform dim appearance across the display or in certain areas compared to others? Can you also share an image of the back of the PCB?
  Have you just purchased this display and seeing these issues right from the start, or have these displays been in use for some time?
  
  Best,

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  dfishman

  • March 25, 2020 08:29

  Thank you for the note.
  
  I'm attaching pictures of the display and back of the PWB.
  The quality of the characters is very good, but it seems dimmer than when it was first plugged in. The display is about 3 weeks old.
  I added another picture with the display showing 2 lines. The brightness has definitely been reduced.
  
  Is that to be expected? Or is it proof that the boost circuit is not working.
  
  Also, i noted that resistor R1 looks slightly charred, as if it overheated. Also, C5 has only 4.3V across it.

  

  

   

  

   

  « Last Edit: March 27, 2020, 11:34:14 AM by dfishman »

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  Alee_S

  • March 27, 2020 15:33

  Hi dfishman,
  
  The display in general does look as bright as expected from a far perspective.
  But if you are comparing the brightness of each row compared to the next, the brightness of the pixels will vary depending on how many pixels in a certain row are being lit. This is due to the fact that these OLED displays use Passive Matrix OLED technology and may experience some drawbacks in proper voltage control of each pixel.
  
  Unfortunately we are not in the office currently due to the pandemic, so i cannot test a unit from stock in our lab and verify the expected voltage across the capacitor - just yet.
  
  Best,

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