| 摘要 |
PURPOSE:To provide possibility of dimming a halogen lamp with a dimming device and prevent oscillation of an oscillator from stopping even though DC voltage is missing for a short time. CONSTITUTION:A DC voltage is supplied to an oscillator 11 via No.1 time constant circuit TK1 having No.1 time constant tau1 and No.2 time constant circuit TK2 having No.2 time constant tau2 which is longer than tau1. MOS-FETs 13, 14 are turned on and off alternately, and are connected with a halogen lamp 19 via an output transformer 15. The No.1 time constant tau1 is set below the time width of trigger pulses emitted by a dimming device, while the No.2 time constant tau2 is set to a value not causing stop of the oscillation of the oscillator 11 even though the DC voltage is missing for a short time. When DC voltage is impressed between DC voltage input terminals T1, T2, the time constant circuits TK1, TK2 shall be actuated in the sequence as named. |
