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.
NTSC/PAL TFT Display - 3.5" Diagonal on 5V
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- adafruit2
- Posts: 22148
- Joined: Fri Mar 11, 2005 7:36 pm
Re: NTSC/PAL TFT Display - 3.5" Diagonal on 5V
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!
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!
- vmax192
- Posts: 5
- Joined: Wed Oct 01, 2014 5:16 am
Re: NTSC/PAL TFT Display - 3.5" Diagonal on 5V
Ok Thank for the answer, i'll command one and i'll give feedback on wether or not it can be ran on 5v.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!
- vmax192
- Posts: 5
- Joined: Wed Oct 01, 2014 5:16 am
Re: NTSC/PAL TFT Display - 3.5" Diagonal on 5V
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)
Thanks by advance
(sorry for my aproximative english, it's not my natal language)
- vmax192
- Posts: 5
- Joined: Wed Oct 01, 2014 5:16 am
Re: NTSC/PAL TFT Display - 3.5" Diagonal on 5V
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
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
- adafruit_support_mike
- Posts: 67446
- Joined: Thu Feb 11, 2010 2:51 pm
Re: NTSC/PAL TFT Display - 3.5" Diagonal on 5V
Glad to hear it's working for you!
Do post a photo please. It's always good to see a circuit that works.
Do post a photo please. It's always good to see a circuit that works.
- vmax192
- Posts: 5
- Joined: Wed Oct 01, 2014 5:16 am
- adafruit_support_mike
- Posts: 67446
- Joined: Thu Feb 11, 2010 2:51 pm
Re: NTSC/PAL TFT Display - 3.5" Diagonal on 5V
Looking good!
Forum rules
Talk about Adafruit Raspberry Pi® accessories! Please do not ask for Linux support, this is for Adafruit products only! For Raspberry Pi help please visit: http://www.raspberrypi.org/phpBB3/
Talk about Adafruit Raspberry Pi® accessories! Please do not ask for Linux support, this is for Adafruit products only! For Raspberry Pi help please visit: http://www.raspberrypi.org/phpBB3/