| 摘要 |
PURPOSE:To obtain a desired illuminance power by turning on or off optionally a switching element of a current control circuit comprising plural series connection circuits each consisting of a switching element and a resistor connected in parallel so as to control a driving current of an LED. CONSTITUTION:A basic unit is formed by connecting circuits in series each comprising a switching element (103a-103h) and a resistor (104a-104h) connected in parallel. When a switching element 103 is turned on, an LED driving current flows to the switching element but does not flows to a resistor 104. Conversely when the switching element is turned off, since the resistance of the switching element 103 is sufficiently larger than the resistance of the resistor 104 connected in parallel, the LED driving current flows to the resistor 104. Thus, the LED driving current is controlled by optionally turning on or off the switching element 103 of the current control circuit. Thus, desired illuminance power is obtained. |
