NTSC/PAL TFT Display - 3.5" Diagonal on 5V

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vmax192
 
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NTSC/PAL TFT Display - 3.5" Diagonal on 5V

Post by vmax192 »

Hello,

i'm referring to this product : http://www.adafruit.com/products/913 . Is someone managed to run this on 5V ? I know the spec says 6V minimum but is there a way/hack to run the screen at 5V ?

thanks by advance.

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adafruit2
 
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Re: NTSC/PAL TFT Display - 3.5" Diagonal on 5V

Post by adafruit2 »

its *probably* possible. the display and driver is a 3.3V device with an LT1117 regulator (1.2V dropout) so maybe there's an extra protection diode that's adding 0.7V or so to make it juuuust slightly too much dropout? so maybe the regulator just needs replacing with a lower dropout, or a diode can be removed (and be extra careful!).

However, we have no actual idea or tutorial on that. it's all guessing :)

We used our samples at 5V and it worked, but some other customers said it didnt so we updated the docs to say 6V min so it may actually work 'out of the box' at 5V

your mileage may vary!

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vmax192
 
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Re: NTSC/PAL TFT Display - 3.5" Diagonal on 5V

Post by vmax192 »

adafruit2 wrote:its *probably* possible. the display and driver is a 3.3V device with an LT1117 regulator (1.2V dropout) so maybe there's an extra protection diode that's adding 0.7V or so to make it juuuust slightly too much dropout? so maybe the regulator just needs replacing with a lower dropout, or a diode can be removed (and be extra careful!).

However, we have no actual idea or tutorial on that. it's all guessing :)

We used our samples at 5V and it worked, but some other customers said it didnt so we updated the docs to say 6V min so it may actually work 'out of the box' at 5V

your mileage may vary!
Ok Thank for the answer, i'll command one and i'll give feedback on wether or not it can be ran on 5v.

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vmax192
 
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Re: NTSC/PAL TFT Display - 3.5" Diagonal on 5V

Post by vmax192 »

On my project i have two regulated lines, one 5v and one 3.3v so maybe i'll be able to bypass the original regulator to avoid theses contraints. If anyone already tried that it would be nice to know.

Thanks by advance

(sorry for my aproximative english, it's not my natal language)

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vmax192
 
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Re: NTSC/PAL TFT Display - 3.5" Diagonal on 5V

Post by vmax192 »

Hi everyone,

quick update, i managed to run the board on 5v by applying 5v on the pin n°3 of the ams1117 regulator ! If anyone interested i'll post a picture of the hack i used

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adafruit_support_mike
 
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Re: NTSC/PAL TFT Display - 3.5" Diagonal on 5V

Post by adafruit_support_mike »

Glad to hear it's working for you!

Do post a photo please. It's always good to see a circuit that works.

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vmax192
 
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Re: NTSC/PAL TFT Display - 3.5" Diagonal on 5V

Post by vmax192 »

Image
Image

as you can see i bridged the 3.3v on the third pin of the ams1117. Power this pin in 5v and tada ! circuit is working.

Later in my project i completely removed the ams1117 since i already had 5v and 3.3v regulated lines.

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adafruit_support_mike
 
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Re: NTSC/PAL TFT Display - 3.5" Diagonal on 5V

Post by adafruit_support_mike »

Looking good!

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