| 摘要 |
<P>PROBLEM TO BE SOLVED: To automatically determine which of at least two kinds of light emitting element groups (for example, LED series circuits) is connected in one power supply circuit, and to drive the light emitting element group with a constant current value that the light emitting element group requires. <P>SOLUTION: In a power supply circuit 100, a microcomputer 151 previously stores correspondence between a lighting number and a dimming degree of an LED series circuit 851 and a current value of a constant current output from a power conversion circuit 120. The microcomputer 15 determines a lighting number of the LED series circuit 851 based upon a voltage detected by a voltage detection circuit 123 and applied from the power conversion circuit 120 to the LED series circuit 851 in a state in which the power conversion circuit 120 outputs a constant current of 15 mA, and makes the power conversion circuit 120 output a constant current having a current value corresponding to a combination of the lighting number and a dimming degree commanded by a dimmer 103. <P>COPYRIGHT: (C)2012,JPO&INPIT |
