Patent ID: 6570343
Filing Date: 2003-05-27
Classification: H02M,H05B,Y02B,Y10S

Abstract:
A device for turning on light comprising:a dimmer which receives a commercial AC (alternating current) voltage and outputs an AC voltage having a controlled conduction phase angle; DC (direct current) voltage generating means for generating a DC voltage from the AC voltage output from the dimmer; a first resonance circuit which includes a first capacitor connected in parallel with a discharge tube to be lighted and whose resonance frequency is determined according to an equivalent impedance of the discharge tube; switching means for switching the DC voltage generated by the DC voltage generating means to generate a high-frequency current and for supplying the high-frequency current to the discharge tube via the first resonance circuit; wherein a switching operation of the switching means is controlled by a phase of a resonance current flowing through the first resonance circuit such that the switching means does not act as a capacitive impedance to the dimmer; and wherein the dimmer adjusts a conduction phase angle of the AC voltage output from the dimmer, thereby changing the DC voltage generated by the DC voltage generating means, thereby changing a frequency of the high-frequency current generated by the switching means and supplied to the discharge tube via the first resonance circuit, thereby changing a current flowing through the discharge tube, thereby changing a brightness of the discharge tube.