This well-known integrated circuit LM2575, is a voltage regulator In switching and is delivered in 4 variants:

- three variants with fixed output voltage (LM2575-5, 12 or 15);

- a variant with adjustable output voltage (LM2575-ADJ);

The diagram shown can be used for any of the first three variants of the C.I. We will thus obtains voltage sources with the output voltage of

+5 \ ;, + 12V or + 15V. The first variant admits at the entrance voltages between 7 and + 35V, the second between 15 and + 35V and the last from 18 to + 35V. The simplicity of the circuit is noticeable. Is recommended that the two electrolytic capacitors are good quality, with the lowest possible losses and in no case with tantalum. The diode is an ultra-fast Schottky diode. BUT. it is provided with short-circuit protection and excessive heating. The maximum input voltage will not exceed 35V. The assembly can provide an output current of 1 A. Having the general advantage of stabilizers In switching, namely poor power dissipation, circuit integrated can be used without cooling radiator.

Using integrated circuits manufactured by National Semiconductor LM1575 or LM2575 a switching source with a 5V output can be made using very few electronic components. Using these circuits you can use an input voltage between 8 and 32 volts.

These 5V switching regulators require only a shock, a recovery diode and a pair of electrolytic capacitors.

The diode is type 1N5822 or BYW29 (Philips); any fast diode can be used; in any case; do not use an ordinary diode type 1N4001 or similar.

The shock is a ready-built 330 uH coil, which must be able to withstand currents of at least 1 A.

Construct the source with a common, star-shaped mass point, as shown in the diagram. The maximum current that can be discharged by the stabilizer is about 1 A.

Note: I am not the original author of this circuit.