Light modulation control unit, illumination system, and facility apparatus

An illumination system comprising:

• a light source circuit comprising a semiconductor light-emitting element;
• and
• a light modulation control unit configured to perform light modulation control on the light source circuit,
• the light modulation control unit comprising:
• a switching element configured to be electrically connected between the light source circuit and a DC power supply, the DC power supply being configured to output a DC voltage having a voltage value capable of causing the semiconductor light-emitting element to emit light;
• and
• a control circuit configured to control a switching operation of the switching element,
• the control circuit being configured to perform switching of the switching element with a duty ratio corresponding to a light modulation level such that the DC voltage that is outputted from the DC power supply is converted to a square wave voltage, and the square wave voltage is outputted to the light source circuit, and
• the square wave voltage having an amplitude equal to the voltage value of the DC voltage that is outputted from the DC power supply.

A facility apparatus comprising:

• a light source circuit comprising a semiconductor light-emitting element;
• a light modulation control unit configured to perform light modulation control on the light source circuit;
• and
• a facility apparatus body configured to hold the light source circuit and the light modulation control unit,
• the light modulation control unit comprising:
• a switching element configured to be electrically connected between the light source circuit and a DC power supply, the DC power supply being configured to output a DC voltage having a voltage value capable of causing the semiconductor light-emitting element to emit light;
• and
• a control circuit configured to control a switching operation of the switching element,
• the control circuit being configured to perform switching of the switching element with a duty ratio corresponding to a light modulation level such that the DC voltage that is outputted from the DC power supply is converted to a square wave voltage, and the square wave voltage is outputted to the light source circuit, and
• the square wave voltage having an amplitude equal to the voltage value of the DC voltage that is outputted from the DC power supply.