Patent ID: 7952295

Claim:
An illuminating device comprising: a constant-current power supply whose output current can be variably set by a PWM control; a light emitting module including paired main terminals that can be connected to the constant-current power supply and one or more light sources connected between these paired main terminals, and that is attached removably to the constant-current power supply; an information output unit that is provided in the light emitting module that includes a resistor connected between the main terminals of the light emitting module and that outputs connection information of the light emitting module by at least either of the main terminals of the light emitting module; and a control unit that recognizes a current that flows to the resistor due to a voltage generated in an OFF period of the PWM control of the constant-current power supply between the main terminals of the light emitting module the connection information outputted from this information output unit of the light emitting module connected to the constant-current power supply and varies the output current of the constant-current power supply according to the connection information.