Anthony Mullen

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8 years, 8 months ago.

POWER

Hi David I ordered the 3.3V display by accident but i just wanted to know do we use a seperate psu to power the display? I got 4SPI,resistive touch and 3.3V 4.3" display

Question relating to:

Last updated: 29 Mar 2020
Simple demo for the Raio RA8875 Based Display with a 4-wire SPI interface. LCD, RA8875, SPI, TFT, WQVGA

1 Answer

Paul Staron
8 years, 8 months ago.

You can change the solder jumpers on the display board to work at 5v. The data sheet indicates the jumper settings you need to change. I did this on my 8" display. You can also change the interface settings as well.

I believe the smaller displays may run from the LPC1768 5v regulator. 3.3v mode draws more current than the Mbed can supply.. However I would recommend to use a separate power supply. You can also power the Mbed from this as well.

Accepted Answer

Thanks Paul When you say 800mA is that the required current for the display alone as I read the model current is 230mA I'm not sure what model current is but I presumed it was the required current

posted by Anthony Mullen 11 Sep 2015

My display is the 8 inch size version, runs at about 350mA @ 5V. Yours will be as you say around 230mA depending on backlight level. The Mbed schematic indicates 460mA capability from the 5v pin here:

https://developer.mbed.org/media/uploads/chris/mbed-005.1.pdf

Should be okay but check it does not get hot as it does not have a heat sink. The Mbed runs using the 3.3v regulator.

posted by Paul Staron 11 Sep 2015