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Miniature 5v Line Powered Isolated
Supply July 20, 2009
Often a circuit requires a 5v DC supply to power some logic circuits. The
conventional method is to use an AC wall adapter. But, many systems, which bring
AC power onto a circuit board, need a small AC to DC power supply right on the circuit
board. The circuit below provides such a supply. It uses a classic series
capacitor charge pump which acts as a current limiting device. A full wave
rectifier, a filter capacitor and a zener diode provide an off-the-shelf isolated DC
to DC converter with a 24v DC input. The miniature converter from CUI generates
a regulated +5v output, rated at 100ma. By doubling the size of the capacitor C1
the circuit can be pushed to produce 200ma of output current. Also, the same
front end circuit can be used with other CUI converters. They sell 3.3v, 12v and
15v supplies as well as the 5v unit shown.
Click
on Drawing Below to view PDF version of Schematic
