Anyone have a favorite and simple power supply design for 24 - 50 volts dc to 5

Don M

Looking for a simple (read low parts count) and compact design. Only needs to be capable of approx 1 amp max or less. I have looked at several switching type regulators but the stumbling block seems to be the upper input voltage limit (50v).

Leon

Nat Semi has some switchers that can accept up to 75V input.

Leon

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Amateur radio callsign: G1HSM

LilDi

Here is a good link for motors

http://www.robotmarketplace.com/products/motors_main.html

VIRAND

It can be done with two transistors, tapped coil (perhaps wound on a toroid core), two diodes, a capacitor,
and the voltage regulator of your choice. The simple circuit would convert 50VDC to 12VDC and is a step-down
multivibrator inverter, (the step up from battery to AC outlet version invented probably around 1960).

The coil is probably somewhat critical; if it has too little inductance then the transistors will lose their
magic smoke. The coil may be replaced by a 120 to 24 VAC transformer center-tapped on both sides,
but a coil able to oscillate at much higher frequency than 60Hz is lighter and more efficient.

This has not been tested. It should be tested at 50 V in series with a 40 watt light bulb, which limits the
current and should not light up except dimly when the output is intentionally shorted as a transistor heat test.
2N3055s may work. Resistors may be necessary as the base to collector cross-connections.
Use 2N2955s and reverse input polarity if you must have common negative ground,
or otherwise use a dual winding center-tapped transformer instead of a coil.

              ______________
              |         |         |
              _         |+12   _
              A        =        A  diodes,  output voltage in capacitor.
              |         |         |                
/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\     coil
|                       |                        |
|_____              (+50Vin)   _______|
\        \_________  _________/          /
  \ ||                 X                     ||/ C   X means wires crossing but not touching
    ||-------------/ \-----------------||          because C and B of both transistors 
  / ||                                    B  ||\ E      are cross connected.
/                                                  \
|                                                  |
|-------------------+--------------------
                          |
                       (0 V)  (-- side of 50V)

This is an experimental untested design, based very old technology,
and may not work as-is without some additional parts and careful adjustment.
I designed it spontaneously and would not expect it to work on the first try.
I do not recommend buying new parts for testing this design. Other power transistors can be tried.
Note that it is similar to a simple inverter circuit called "Joule Thief" but is being used in step-down mode.
The schematic is ascii because I do not have Propeller Font on this computer.

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I should be typing in Spin now.
Coming soon. My open Propeller Project Pages and favorite links index.

DonEduardo

I use the lm2576HV all the time. Works great. Bought some on ebay for pretty cheap, but locally they are kind of expensive I think >$5.00 but very low parts count.