"stefanhanoi" wrote in
oups.com:

Other simple solutions?

Why not use one of the ICs that is already designed for this purpose? Sure
reduces your parts count to nearly zero, and the output is nicely regulated
by the IC's circuitry.

http://www.mouser.com/?handler=data....Ne=500&N=57960

cheap....as low as 48 cents. Mouser will sell you just one if you're
willing to pay the shipping....

Larry,
those DC/DC charge pumps obviously produce an output voltage that is
higher than the input voltage, or negative. But the output still has a
common ground (0V) with the input voltage. For the panel meters we need
a supply voltage that is within the range of the available voltage (12
to 24V available, 9V needed) (no need for those DC/DC charge pumps),
but that needs to be isolated/free flowing from the main/"primary"
power supply so that we can measure it, i.e. no common 0V/GND. I don't
see how the ICs that you show can do that. On the other side, I wonder
whether there are not really specialized ICs that do that.

Thanks,
Stefan