| 摘要 |
PROBLEM TO BE SOLVED: To provide a power supply capable of controlling input electric power and supplying a load with the electric power required. SOLUTION: A commercial power supply Vs is full-wave rectified by a rectifying circuit DB to obtain a ripple power supply. A discharge lamp La is provided as a load. One end of an inductor L0 is connected to the positive pole of the current output end of the rectifier circuit DB, and the other end to the connection point of switching elements Q1, Q2, which are turned on and off by control signals S1 to S4 from a control circuit. This control circuit has a steady-state control mode in which the switching elements Q1, Q4, Q2, Q3 arranged at the diagonal positions are turned on simultaneously, and those Q1, Q2, Q3, Q4 connected in series are each turned on and off alternately and an input power control mode in which the 'on-off' of only the switching element Q2 is stopped intermittently to control input electric power. |
