| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a dimmer capable of preventing the flicker of a light source in the case of the fluctuations in a power supply voltage from an external power supply due to an instantaneous power failure. <P>SOLUTION: A dimmer comprises: a triac Q1 with a self-holding function, which is connected in series with a commercial power AC1 and a lighting device 1 of which the light source is a light-emitting diode 10A; a phase detection circuit 21 which outputs a synchronizing signal when a power supply voltage of the commercial power AC1 reaches a predetermined voltage value V1; and a control circuit 22 which generates a trigger signal for causing the triac Q1 to be turned on/off so as to change a conduction angle of the triac Q1. The control circuit 22 generates the trigger signal on the basis of the rising edge of the synchronizing signal, and stops the generation of the trigger signal when an interval between the rising edges of the synchronizing signal falls outside a reference range. <P>COPYRIGHT: (C)2013,JPO&INPIT |
