| 摘要 |
PROBLEM TO BE SOLVED: To provide an LED lighting circuit which can solve circuit design restriction that an LED is susceptible to an excessive current, a reverse voltage, static electricity, a surge current, heat and the like and a forward voltage (Vf) has an individual difference with large deviations, and which is inexpensive and highly efficient in power with a long life. SOLUTION: Four sets of circuits each being formed by connecting a rectifier diode in series to a prestage of a circuit formed by connecting a capacitor in parallel with a multistage LED, are substituted for four diodes of a full wave rectifier bridge widely used in common, respectively, and a commercial AC power source is connected to a bridge input and a constant current source is connected to a bridge output. (1) An inductor is connected in series with a rectifier diode side of the capacitor to prevent an inrush current. (2) A small-capacity capacitor is connected in parallel with the constant current source to reduce a switching noise. (3) A high resistor is connected in parallel with an electrolytic capacitor for discharging when the power is off to prevent an electrical shock. (4) If there is a margin for a dynamic range of the constant current source, the multistage LED is connected in series with the constant current source to blink for use. COPYRIGHT: (C)2011,JPO&INPIT |
