Lpc2000

After messing with this one for years I finally went to Winstar and get 
mine on baord for free, however prior to that for digital control I used 
the MAX686, not a cheapest solution but solid, and not too expensive. 
The other cheap way might be to use an MC34063, they are only $1, but no 
digital control, or ON/OFF control without a bit of messing. I used an 
MC14051 ($0.38) and a variety of resistors to get numerous voltage steps.

Cheers

Al

Sean wrote:

>Sorry for the OT post, but I figure that since this is something common to 
>embedded projects you guys might have an elegant solution.
>
>I'm looking to create a contrast voltage (typ -13V 10mA) and a LCD Drive 
>voltage (min -23V 10mA), onboard I have +5V, +3.3V and Vin which is 
>typically +12V.  Ideally the contrast should be digitally controllable.
>
>The big part of the problem: it needs to be relatively cheap.
>
>I've been having a hard time trying to figure out the best way to do 
>this.  The best way that I can think of so far is going to be via voltage 
>multipliers.  I.e. take 3.3, invert and quadruple to get -13.2V for the 
>contrast, and then double again to get -26.4V for the LCD Drive.  I don't 
>know however if I can handle 10mA this way after octupling the voltage.
>
>I'm trying to stay away from switched regulators, as they can get expensive.
>
>Thanks for any suggestions that you may have.
>
>-- Sean
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>Yahoo! Groups Links
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