| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To set a voltage corresponding to the rated current of a load circuit as a reference voltage and control a load current within a range posing no adverse effects to a life characteristic and the like according to the reference voltage. <P>SOLUTION: A lighting system comprises: the load circuit connecting in series a lighting head 3, a switching element Q1 and a current detection resistor Rs; a reference voltage setting circuit 4 for holding as a reference voltage Vref a voltage Vs corresponding to a load current detected by the current detection resistor when a rated voltage is applied to the load circuit and the switching element is switched on; and a current control circuit 8 for controlling the switching element such that the detected voltage Vs has a constant relationship with the reference voltage Vref when a predetermined voltage is applied to the load circuit. The reference voltage setting circuit and the current control circuit cooperate in limiting the current flowing through the lighting head within a controlled range. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
