RE: AW: [Lcd4linux-devel] USB based hd44780 units ...

[Luis.F.Correia <Lui...@se...>]

Hi Michael,

> -----Original Message-----
> From: Michael Reinelt [mailto:re...@eu...] 
> Sent: Thursday, January 26, 2006 10:54 AM
> To: lcd...@li...
> Subject: Re: AW: [Lcd4linux-devel] USB based hd44780 units ...
> 
> Hi Luis,
> 
> > there is a much more cheaper source for those DC-DC converters, old 
> > ethernet cards with the BNC connector, it is a big black 
> block, shown 
> > vertically with the letters YLC, in this link:
> 
> You are right, but (there's always a 'but' :-)
> 
> A 5V to negative converter would be better here (as there are 
> no 12V when powered by USB).
> 
> These convertes from ethernet cards are all quite large (at 
> least these that I've seen), while the converter I've been 
> using are really small (and may be mounted somewhere on the board)

You are also correct, but let's face it, a display that requires
negative voltages, is usually an old device which would certainly
require a lot more then the 500mA that the USB port supplies, 
therefore requiring a separate power source.

Nonetheless, the current DC-DC converters are indeed quite small
while also being effective.

Luis