| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a lighting control device of vehicular lighting fixture performing switching operation depending on a current boundary even if a circuit is simply constituted. <P>SOLUTION: A transistor 20 is turned on and off by output of a switching signal generating circuit 30. When the transistor 20 is turned on, the energy accumulated in a transformer T1 is released to a rectifying-smoothing circuit 14, and when the transistor 20 is turned off, and a non-current period is generated at secondary side of the transistor T1 during the process that a transistor 46 is turned off, and charging voltage of a capacitor C3 is increased, a capacitor C4 is charged in accordance with the length of the non-current period, current flows through a transistor 48 in accordance with the charging voltage, and the charging voltage of the capacitor 3 is increased. When the voltage of the capacitor 3 exceeds a standard voltage 60, the output of a comparator 58 becomes low level, and a cathode of a diode D5 is grounded, the switching signal is reversed from a low-level to a high-level, and an off-period of the switching signal is shortened. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
