| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To realize at a low cost and with a simple structure a circuit in which the LED current can be changed in between high and low states and the imbalance of light output of each LED circuit is suppressed in either state of high output and low output in the LED lighting circuit of series and parallel connection, that is constructed of a plurality of LEDs. <P>SOLUTION: A current mirror circuit which makes almost the same the circuit current of the LED1 and the LED2 by the transistors Tr1, Tr2 and resistors R1, R2 constructed in parallel several pieces in the DC power source Vdc is constructed, and the current flowing in the above current mirror circuit is made a reference current that is nearly determined by the voltage of the DC power supply Vdc and the resistors R4, R5, R3, and this reference current is switched over by a switch SW. <P>COPYRIGHT: (C)2004,JPO</p> |
