| 摘要 |
PROBLEM TO BE SOLVED: To provide a lighting device of a vehicular instrument, capable of preparing a desired drive signal for PWM control even without using a dedicated port. SOLUTION: The lighting device for the vehicular instrument having an illumination light source 6 of a display means for display vehicle information and a control means 1 for light adjusting control of the light source 6 is provided with a triangular wave generation means 2 to generate a triangular wave 2a synchronized with a pulse signal 11a generated from the control means 1, a reference voltage generation means 3 to generate a reference voltage 3a that can be changed by the control means 1, a comparison means 4 to compare the triangular wave 2a and the reference voltage 3a, generate a square wave having a duty ratio corresponding to the comparison result, and to output the square wave as the drive signal 4a, and a switch means 5 to switch power supply to the light source 6 according to the drive signal 4a from the comparison means 4. COPYRIGHT: (C)2009,JPO&INPIT
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