Supply voltage for KZW series OLED

MustardMan

• August 23, 2017 02:33

Hi,
Searched but found no answers to my question:

I am designing for a KZW series "5" version because the "3" version is almost impossible to actually buy. The "5" datasheet states the supply voltage range as 4.8 to 5.3 volts, nominal 5.0 volts.
However, the reseller (Digikey in this instance) states the displays will operate from 3v to 5.3 volts...
>> so who is right?
>> have newhavendisplay updated their design but not updated the datasheet (with their last update in March this year!!)?

I am doing a new design to replace an LCD. Reliability is king, and the LCD would fail at high temperature. I *do not* wish to just go with a 3.3 volt supply and *hope it works*. I need to design this thing to always work!!

The (old) LCD is a 5v part, but the micro drives signals at 3v3. The specs for the LCD state this is fine... but not so with the OLED (0.8 x Vcc) for Vih. Thats 4 volts for Vih...

To design properly I either need to drop the supply to 3.3 : but will the display work at this voltage?; or
Level translate the logic signals to the display and run the whole thing at 5v.

As per usual, I'm really under the pump to deliver a design.

Many thanks for taking the time to read, and even better if you can respond.

PS: the "CW" 2.8 volt displays are also available, but the suppliers' (both Digikey and Mouser) stock is worryingly low.

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  Saurabh_B

  • August 23, 2017 10:50

  Hello,
  The standard character OLED displays can be powered via 3.3V, however please note that the brightness of the OLED panels will be dimmer than what is optimal.
  
  You would need to apply 3.3V to the VDD, and have a logic voltage of 3.3V as well.

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  MustardMan

  • August 23, 2017 17:14

  Thanks for the quick reply!
  
  I'll consult with the project manager to see what sort of brightness is required (eg: daylight, but in the shade).
  
  Are there any datasheets that illustrate how the brightness changes from 5v to 3v3?
  
  Cheers,
  MM

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  Saurabh_B

  • August 24, 2017 08:38

  Unfortunately we do not have datasheets on the change in brightness.
  However we can see that its half to 2/3 as bright as a 5V, this would also be dependent on the color.

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  MustardMan

  • August 24, 2017 16:28

  Thanks, that is excellent information.
  
  According to the project manager, this thing is usually located outside, but in a shaded area, and occasionally used in direct sun. Shading by hand is acceptable for the user.
  
  I will design my device to use the existing 5v supply and use a level translator to step up the logic drive from the microprocessor.
  
  I have a couple on order and will trial them before committing.
  
  Again, appreciate your time for the replies.
  MM

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  Saurabh_B

  • August 25, 2017 08:09

  Awesome, please let us know how the project works.

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