Light control apparatus for light emitting device and illumination system

A light control apparatus for a white LED light-emitting device, comprising:

• a driving current supply unit which supplies an AC current as a driving current via a pair of terminals to the white LED light-emitting device including a set of LED elements having mutually different light emission wavelength regions connected in parallel while providing opposite polarities and the pair of terminals provided to supply the driving current to the set of LED elements;
• an individual amount defining unit which defines a positive driving current amount and a negative driving current amount respectively to be supplied to the white LED light-emitting device in a positive half cycle and a negative half cycle included in one cycle of the AC current respectively;
• and
• an operation unit which is provided to impart, to the individual amount defining unit, an operation amount for adjusting the positive driving current amount and the negative driving current amount defined by the individual amount defining unit,
• wherein the individual amount defining unit includes:
• a triac which controls supply start and supply stop of the positive and negative driving currents, which respectively correspond to the positive and negative driving current amounts, with respect to the white LED light-emitting device;
• a trigger generating unit which imparts, to the triac, a supply start trigger for the positive driving current and a supply start trigger for the negative driving current;
• and
• two time constant circuits in which a portion disposed on one side from a movable point possessed by a variable resistor is a resistor a for determining a time constant A for allowing the trigger generating unit to generate the supply start trigger for the positive driving current and a portion disposed on the other side from the movable point is a resistor b for determining a time constant B for generating the supply start trigger for the negative driving current;
• and
• the operation unit includes a first adjusting unit for adjusting a position of the movable point of the variable resistor depending on an operation.

A light control apparatus for a white LED light-emitting device, comprising:

• a driving current supply unit which supplies an AC current as a driving current via a pair of terminals to the white LED light-emitting device including a set of LED elements having mutually different light emission wavelength regions connected in parallel while providing opposite polarities and the pair of terminals provided to supply the driving current to the set of LED elements;
• an individual amount defining unit which defines a positive driving current amount and a negative driving current amount respectively to be supplied to the white LED light-emitting device in a positive half cycle and a negative half cycle included in one cycle of the AC current respectively;
• and
• an operation unit which is provided to impart, to the individual amount defining unit, an operation amount for adjusting the positive driving current amount and the negative driving current amount defined by the individual amount defining unit,
• wherein:
• the individual amount defining unit includes an integration circuit which generates a triangular wave voltage having a period equal to that of an AC voltage of the AC current, a non-inverting input terminal into which the triangular wave voltage generated by the integration circuit is inputted, an inverting input terminal into which a voltage obtained by divining, by a variable resistor, a DC voltage provided by rectifying the AC voltage is inputted as a reference voltage for defining a slice level of the triangular wave voltage, and a comparator which outputs positive and negative rectangular wave voltages as a result of comparison between voltages inputted from the non-inverting input terminal and the inverting input terminal respectively;
• the driving current supply unit supplies a positive driving current, which corresponds to the positive driving current amount, to the white LED light-emitting device in a period of time in which the positive voltage is outputted from the comparator, while the driving current supply unit supplies a negative driving current, which corresponds to the negative driving current amount, to the white LED light-emitting device in a period of time in which the negative voltage is supplied from the comparator;
• and
• the operation unit adjusts a resistance value of the variable resistor in accordance with an operation.