USB Power

**GRUNT** · 02-20-2004, 07:51 AM

Extracted a 3 port USB powered HUB from an old monitor.

It requires 6.3v.

What is the best way to drop 12v to 6.3v or up 5v to 6.3v
Don't think it will require much amps!

The power supply it used, input is 240v and dose not work.

I have two max788 could I use them?
If yes what is the eased way to connect them?

Thanks for your help.

**droswell** · 02-21-2004, 07:07 AM

http://www.radioshack.com/product.as...%5Fid=276-1778

It even has schematics on the back- or at least it used to. If it doen't, let me know. I can throw a design together for you.

Just keep in mind I think you can only get ~1A from it, and that's with a heatsink.

**GRUNT** · 02-21-2004, 12:19 PM

Thanks Droswell,

Found this link that shows how to use them.
If I understand, When you adjust the resistance on pin (1) this adjusts the output voltage.
With 12v input, min output=1,25v and max output=12v-1,25v.
1,25v=Reference Voltage of the LM317T

http://www.bit-tech.net/article/32/