| 摘要 |
PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device reduced in size and high in efficiency, capable of reducing switching loss of a switching element and equipped with: a DC power source; a step-down chopper connected to an output side of the DC power source and equipped with a switching element and an inductor; a smoothing capacitor connected to the output side of the step-down chopper; a discharge lamp connected in parallel to the capacitor; and an electricity controlling circuit for controlling electricity supplied to the discharge lamp by turning the switching element on/off at high frequency and controlling switching frequency. SOLUTION: In the case where the switching frequency is in a state of a steady state frequency with a lower frequency than the predetermined frequency, the switching element is controlled to turn on when the electric current flowing through the inductor is substantially zero while the switching element is turned off, and when the switching frequency is in a high frequency state which is higher than the predetermined frequency, an electric current controlling circuit for controlling the electrical current flowing through the inductor to be a discontinuing electric current having pauses in the electric current. COPYRIGHT: (C)2004,JPO |
