DEVICE OF FORMING DRIVING VOLTAGE AMPLITUDE MODULATED IN A SHAPE OF SINUSOIDAL WAVE, LIGHTING APPARATUS, AND FORMING METHOD OF DRIVING VOLTAGE FOR WHICH AMPLITUDE MODULATION IS CARRIED OUT IN A SHAPE OF SINUSOIDAL WAVE

摘要

PROBLEM TO BE SOLVED: To provide a device of forming a driving voltage for which an amplitude modulation is carried out in a shape of a sinusoidal wave and make it possible to adjust a modulation depth arbitrarily and without going through stages.

SOLUTION: A first switch is driven at every clock of a first signal in a clock of an amplitude modulation frequency and a second switch is driven at every clock of a second signal which is time-offset against the first signal and is shorter than the first signal, and an LC circuit acts as a filter for a signal which arises at a contact point between the switches when the switches are driven and passes a direct current voltage component and a sinusoidal wave component of a signal having a basic frequency of the clock and eliminates mainly harmonics.

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