Usb Protoboard power question

bambino

Hi Gang,
I want to power a protoboard from a standard computer power supply! Can I supply the board power with the 5 V line off of the computer power supply? I only need the 3.3 Volt rails, but will the low voltage give me problems with the· 5 volt regulator?

Leon

The 5V regulator won't work; it needs a minimum differential between the input and output. See the data sheet.

Leon

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Amateur radio callsign: G1HSM
Suzuki SV1000S motorcycle

Mike Green

Yes, you could power the Protoboard using an external +5V power supply. The 3.3V regulator is just as happy with the output of the 5V regulator as it would be with an external source of 5V.

Rayman

I did this before by connecting +5V where you're supposed to connect servos...

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My Prop Info&Apps: ·http://www.rayslogic.com/propeller/propeller.htm

bambino

Thanks again,
I would just connect the 12 volt line , but that would probably be too hot a circuit, and since I don't need the 5 volt rail anyway I hope this will work!

localroger

bambino, you can power the protoboard from a 12V regulated supply safely; the 5V regulator might start to get warm if you run it flat out, but you'll probably be OK if there are no hungry peripherals. But if you don't need the 5V you can do as Rayman suggests; on the protoboard the output of the 5V regulator feeds the 3.3V regulator, and you can connect regulated 5V directly to the OUTPUT of the 5V regulator, which is conveniently accessible at the servo jumper.

bambino

Yes, I do intend to use it a lot. In fact It will run perminantly. I like the servo connection idea, will probably use that.

Thanks again