| 摘要 |
PROBLEM TO BE SOLVED: To provide an instrument circuit for a vehicle capable of reducing a processing load of an instrument side control means despite of two external signal wires for operating a sensor side circuit. SOLUTION: This instrument circuit for the vehicle is equipped with the sensor side circuit 10 including a Hall element 12 (residual amount sensor), and an instrument side circuit 20 including a power source supply line Lm2 and a microcomputer 21 (instrument control means). A pull-up resistance R0 (voltage variable element) is interposed on the power source supply line Lm2, and an output voltage VS of a battery B to which a voltage drop amount caused by the pull-up resistance R0 is added is taken into the microcomputer 21, and then taken into the sensor side circuit 10 through a wire harness Lo1. The sensor side circuit 10 is provided with a comparator circuit 14 and a current control circuit 15 (control circuit) for controlling the voltage drop amount caused by the pull-up resistance R0 so that a voltage difference between a sensor output voltage corresponding to an analog signal of the Hall element 12 and the output voltage VS of the battery B becomes below a prescribed value. COPYRIGHT: (C)2009,JPO&INPIT
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