David Minkler wrote:
> Hi Roman,
>
> I'd certainly be interested.  I have a 3 transistor voltage inverter
> (+5V to -15V) which I was considering posting (not nearly as elegant
> as your 2 transistor circuits but quite stable).  As you know, we
> frequently get requests on list for such circuits for LCD contrast and
> other (low current) purposes.  Perhaps we can adapt your 2 xstr boost
> circuit to voltage invert.
>
> Best regards,
>
> Dave Minkler


For most low current negative bias, including extended temperature LCD
units, we've being using this without any problem;


  any clock signal
    above 1kHz
        o
        |
       _|_
       \ /  Any inverter
        V
        o
        |
       _|_ 1nF
       ---
        |
        o----|<|----o----> -3V
        |           |
       _|_         _|_-
       \ /         === 1uF
       _V_          |
        |           |
       _|_         _|_
       GND         GND

        1N4148 x 2

/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
Wagner Lipnharski - UST Research Inc
Orlando FLorida - USA - www.ustr.net
/_/_/_/ Atmel AVR Consultant /_/_/_/

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