| 摘要 |
<P>PROBLEM TO BE SOLVED: To determine automatically a light emitting element group (e.g. LED series circuits) connected in one power supply circuit from at least two types of light emitting element groups, and to drive the light emitting element group with a constant current value required by the light emitting element. <P>SOLUTION: In a power supply circuit 100, a microcomputer 151 prestores the correspondence of the number of lamps and the degree of dimming of an LED series circuit 851 and the current value of a constant current being output from a power conversion circuit 120. Based on a voltage being applied to the LED series circuit 851 from the power conversion circuit 120 and detected by a voltage detection circuit 123 while a constant current of 15 mA is output from the power conversion circuit 120, the microcomputer 151 determines the number of lamps of the LED series circuit 851, and makes the power conversion circuit 120 output a constant current of a current value corresponding to the combination of the number of lamps and a degree of dimming commanded from a dimmer 103. After determining the number of lamps, the microcomputer 151 determines the number of lamps again at a periodic timing and checks erroneous determination. <P>COPYRIGHT: (C)2013,JPO&INPIT |
