Low-Cost Ripple Regulator Power Supply
Original Publication Date: 1986-Jan-01
Included in the Prior Art Database: 2005-Mar-08
A technique is described whereby an inexpensive power supply with good regulation provides a single output voltage without the need for a transformer. The circuit functions as a ripple regulator with series pass regulation. When primary input voltage 10 is applied, as shown in the figure, inductor 11 is provided to limit the surge current. Half wave rectifier 12 rectifies the waveform while resistor 13 limits the average current. Resistor 14 raises the gate voltage of power field-effect transistor (FET) 15 so that it is biased on. As the voltage at 16 rises due to the charging of capacitor 17, the voltage at 18 also rises. However, the rise in voltage at 18 is limited due to zener 19. Therefore, the output voltage 20 equals the voltage at 18 minus the voltage drop across transistor 27.