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USB-RS232 Converter Provide Backlight Power 634

jhaislet

New member
Hi, Will the USB-RS232 provide backlight power for a 634? I am wanting to externally mount the 634, and would perfer not to run a 5v power lead from my computer. Would it be ok to use a 5v wall transformer that outputs 2.5A? Or can you not go above 1.0A with the 634 Backlit? Thanks.
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USB LCD Displays - Graphic and Character LCDs with a Keypad

tellis100

New member
Current is different than voltage. The display will only draw what it needs. You could supply 10A to it without hurting it.

You should be able to run the backlight from the USB port. According to the 634 specs the backlight current is 525mA. Most all internal USB ports only supply 500mA. You might have better luck running through a USB hub that is self powered.
 
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jhaislet

New member
Thanks for the clarification on the current draw. Here's what I did on Saturday. I took an old USB cable, and cut the square end off, and spliced the 5v and ground with the LCD. The LCD now gets its power from my powered USB hub. The LCD looks just as bright as if it was plugged into the PSU. Also, the power block for the USB hub is rated at 2.5A @ 5v, so I would imagine it has enough current to continuously power the LCD. Now all I need to do is get the serial-LCD converter, and the entire LCD will be able to run off two USB ports.
 
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