LM317 Low-Cost 3A Switching Regulator

A switching voltage regulator circuit shown in the schematic diagram here can be a low cost solution for your high efficiency requirement electronic circuit design. Unlike other switching regulator circuit that uses special purpose integrated circuit (IC), this circuit uses a standard linear regulator LM317 IC. LM317 regulator IC provide a stable internal voltage reference, and provide the adjustment method. This wide-range output voltage adjustment make it suitable for general purpose power supply in lab application. Here is the schematic diagram of the circuit:

A good capacitor, low equivalent series resistance (ESR) is ideally used for C1 and C4, so you can use a tantalum capacitor for them. A standard electrolytic capacitor can be used but use at least 10 times higher value to compensate, 1000uf for C4 and 470uF for C1. Use 50V rated capacitors for C1 and C4. [Circuit’s schematic diagram source: seekic.com]