I have been trying to build a Raspberry Pi laptop, and I found an issue where my screen required power at all times to run , so I decided to plug the screen in to the USB port in the Raspberry Pi. Unfortunately, this meant that the screen was not receiving enough power from the Raspberry Pi to run. The screen I am using requires 12 volts. Here’s a link to where I bought the screen: https://www.aliexpress.com/item/10-1-inch-Raspberry-Pi-Screen-1024X600-HD-Digital-LCD-Monitor-Display-HDMI-VGA-2-AV/32282336030.html?src=google&albslr=220934139&isdl=y&aff_short_key=UneMJZVf&source=%7Bifdyn:dyn%7D%7Bifpla:pla%7D%7Bifdbm:DBM&albch=DID%7D&src=google&albch=shopping&acnt=494-037-6276&isdl=y&albcp=913263744&albag=48828809226&slnk=&trgt=388120373908&plac=&crea=en32282336030&netw=g&device=t&mtctp=&aff_platform=google&gclid=EAIaIQobChMItJX_8aLa2wIV1CMrCh2HGwZbEAkYECABEgKkqvD_BwE&gclsrc=aw.ds Does anyone know how to fix this? Thanks
2 Answers
Short answer: no way.
Long answer: USB ports can only output 5 Volts.
It's true that your screen came with (citing the product page you linked)
1 * USB to 3.5 DC Power Cable
but that cable is useless for a 12-Volt device like your screen.
To me, it looks like they threw the cable in just to "complete" their offering someway, without paying any attention to whether that piece was suitable for use with the screen or not.
Unfortunately there is no place on a Raspberry Pi from where you can draw 12 Volts. Even if there was one, there's another problem:
- the declared current absorption of your screen is 1 to 2 Amperes;
- at 12 Volts, this means that the power required to run the screen is 12 to 24 Watts (P = V × I)
- this is well beyond the power fed to the Raspberry Pi by its own power supply (5V × 2.5A = 12.5W)
- even if you used a more powerful power supply for the rasPi, one capable of providing enough power for both the board and the screen, the current passing through the Micro USB connector would probably overheat it to the point of damaging your board.
I'm afraid the only way to make the screen work is using a separate 12V power supply capable of sustaining a 2A load. A quick search for 12V 2A power supply on Amazon (or any other suitable e-commerce site) should give you some decent choices.
The USB ports on the Raspberry Pi are 5 Volts. You cannot increase that voltage.
You would need a separate 12 Volt power supply to the screen.
