DIMMING SIGNAL TRANSMISSION CIRCUIT

PROBLEM TO BE SOLVED: To provide a dimming signal transmission circuit that has prevented a wrong dimming signal from being transmitted to the illumination apparatus at the initialization. SOLUTION: A dimming signal transmission circuit 10 is constituted by an dimming signal transmission control part 1 that transmits the dimming data read out from a shared memory through a shared bus 11 to a dimmer as a dimming signal by a serial transmission method, and an OR gate OR1 that outputs to the set terminal of the dimming signal transmission control part 1 by taking the logical sum output of the initialization signal S1 inputted through the noise elimination circuit 2 and the gate signal S2 generated by the dimming signal transmission control part 1. Since the dimming signal transmission control part 1 has the signal level of the gate signal S2 in H level during transmission of the dimming signal, the output of OR gate OR1 is kept compulsorily in H level and the signal level of the set terminal does not become L level. Hence transmission of the dimming signal is not stopped on the way.