Illumination light communication apparatus, illumination equipment, and illumination apparatus

An illumination light communication apparatus to be connected to a light source that emits illumination light due to a current from a constant current generation device flowing in the light source, and that modulates the illumination light of the light source, the illumination light communication apparatus comprising:

• a switch that is connected in series to the light source;
• a signal generator circuit that generates a binary communication signal which controls ON and OFF states of the switch to modulate the illumination light;
• a current suppression circuit that is connected in series to the light source and the switch, and that suppresses the current flowing in the light source so that a current setting value corresponding to a reference value is not exceeded;
• and
• a controller that can change an ON duty ratio of the switch through the communication signal, wherein
• the controller changes the ON duty ratio of the switch during a transition period in which a current flowing in the current suppression circuit changes.