| 摘要 |
PURPOSE:To always control accurately the quantity of energization to the load by always controlling the energization of the laod on the basis of the monitor voltage detected at a fixed point. CONSTITUTION:A microcomputer 12 delivers a trigger signal 18 of a semiconductor switching element 16 which controls the phase of an AC power supply to be applied to a halogen lamp 15. Tht is, the phase control is carried out for a voltage waveform for monitor which underwent the full-wave rectification by the phase control trigger signal of the lamp 15. As a result, the output voltage similar to the effective voltage to be applied to the lamp 15 is delivered to an integration circuit 17. The voltage 17 integrates the output of a generating circuit 14 for waveform of halogen lamp lighting voltage and supplies the integrated output to the A/D terminal of the computer 12 in the form of the monitor voltage. The computer 12 gives the phase control to the energization of the lamp 15 by the zero-cross signal to be applied to a terminal INT as well as the monitor voltage fetched in the prescribed timing and given to the A/D terminal. |
