| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce loss in a transistor provided on the path of a current supplied to a semiconductor light source. <P>SOLUTION: The semiconductor light source lighting circuit 100 comprises an N channel field effect transistor M1 and a current detection resistor RS provided in series on the path of a current supplied to a semiconductor light source 10, and a control circuit which controls the N channel field effect transistor M1 so that the difference between a voltage generated in the current detection resistor RS and a reference voltage Vref is reduced. A bypass resistor RB is provided to form a bypath By of a current supplied to the semiconductor light source 10 having one end that is a second connection node N2 of the N channel field effect transistor M1 and the semiconductor light source 10. <P>COPYRIGHT: (C)2012,JPO&INPIT |
