| 摘要 |
<p>PURPOSE:To make continuous dimming control by turning on and off an operational switch in the two-wire system. CONSTITUTION:An operational switch SW is installed in an AC power supply path to light fixture A, and a power shutoff sensing circuit 3 senses that the power is shut off with turn-off of the operational switch SW. A control part 4 counts the Off time of the operational switch SW from the output of the power shutoff sensing circuit 3. In the case the Off time of the switch SW remains within a specified period of time, a lighting circuit 2 is controlled according to the On time after the switch SW is turned on so that the light- output of a light source 1 is varied continuously. In the case the Off time exceeds the specified period of time, the lighting control of the light source 1 is conducted in a lighting control mode other than the continuous dimming control mode. The power supply path should serve also as a transmission line for the operating signal for the switch SW, and thereby continuous dimming control can be performed in the two wire system.</p> |
