| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a frequency synchronization method of a discharge tube lighting device capable of synchronizing oscillation frequencies with synchronous pulse signals. <P>SOLUTION: The device is provided with an oscillating means 11a generating a triangular wave signal of a first frequency with the same inclination in charge and discharge of an oscillation capacitor and putting on/off a plurality of switching elements by a first positive and negative current pulse, and a pulse current generating means 20 converting the synchronous pulse signals with an output connected with the oscillation capacitor for synchronizing the oscillating frequencies into a second positive and negative current pulse of a second frequency synchronized with the frequency of the synchronous pulse signal and with the same pulse width as an absolute value of current at a duty ratio of 50%. The oscillating means generates triangular wave signals by superposing the second positive and negative current pulse on the first positive and negative current pulse, when the synchronous pulse signals are inputted, so that, different inclination periods of the triangular wave signals are adjusted by a phase difference of the both pulses to have the oscillation frequency of the triangular wave signals synchronized with the second frequency of the second positive and negative current pulse. <P>COPYRIGHT: (C)2010,JPO&INPIT |
