| 摘要 |
PROBLEM TO BE SOLVED: To enable brightness adjustment of an LED, enable brightness adjustment even when connected to a phase control type dimmer for an incandescent lamp, and inhibit a harmonic wave from being generated without using a power factor improvement function.SOLUTION: Time width since voltage in each wave of an undulating voltage obtained by rectifying an alternating current exceeds an operation lower limit value of an SWR control part to be operable until being an operation lower limit of the SWR control part to be inoperable is divided into two or more sections, a pulsating current is directly put into the SWR control part to gradually increase a current value such that the current value does not rapidly increase in each section of each wave and to gradually decrease the current value in the later section, an output voltage is acquired together with an input current with a few harmonic waves by repeating the control in each wave, the output voltage is used to generate an LED drive current, an LED is made to emit light by the LED drive current, section width or the number of sections in each pulsating current is controlled, and an alternating current output voltage subjected to phase control is inputted to thereby increase or decrease the inoperable time, increasing or decreasing an LED lighting time, which performs dimming. |
