| 摘要 |
PROBLEM TO BE SOLVED: To reduce a production cost by constituting a lighting switch so as to be capable of controlling active shut off of a primary side of a lighting transformer. SOLUTION: Enable pulse of a lighting control part 20 having a specified duration time is applied to a switch T1, and the switch T1 is closed for a specified duration time based on the applied pulse. While closing, an intermediate circuit capacitor CZ acts as a DC voltage source, lighting current on the primary side flows to an earth through a series circuit of a choke L3, inductance SL1, primary winding L1, and the switch T1. Preferably, a capacitor C2 is connected to the secondary winding L2 of a lighting transformer TR, specified frequency and specified peak voltage are obtained, and a sine wave lighting pulse having relatively wide width is formed. Preferably, a crown circuit having a diode D2 and a Zener diode Z1 is installed, and used to limit voltage of the switch T1 and to demagnetize a lighting transformer by next lighting pulse. |
