To provide a dimming control device for dimming-controlling a light source based on a set dimming rate, which can dimming-control the light source which is dimming-controlled by phase control by amplitude control based on the same set dimming rate as in the phase control.
The dimming control device 1a includes a zero cross detection part 11 which detects a zero cross; a setting part 13 which determines a dimming rate substantially equal to a set dimming rate based on a time difference between the zero cross and a phase trigger signal; a voltage control part 14 which generates a rectangular wave control voltage V2 the on-duty ratio of which is controlled based on the determined dimming rate; a voltage superimposition part 15 which superposes an alternating voltage V1 on the control voltage V2; and a filter part 16 which smoothes a superposed output voltage V3 and outputs a sine wave lighting voltage V4 to the light source 3 as a dimming control signal. According to this, since the dimming control signal in which the alternating voltage V1 is amplitude-controlled according to the set dimming rate is output, the light source 3 which is dimming-controlled by phase control can be dimming-controlled by amplitude control based on the same set dimming rate as in the phase control.
MATSUDA SHINJI
Katsumi Taguchi
Shinichi Mizuta