| 摘要 |
PROBLEM TO BE SOLVED: To enable a device which electrically drives an electric load the internal resistance of which varies (increases) immediately after starting energization to surely suppress the noise which is produced immediately after starting energization of the electric load. SOLUTION: A driver for a lamp 2 is provided with an FET 6 for controlling current provided in the conducting route from the anode side of a battery 4 to the lamp 2, a resistor 8 for detecting current provided on the upstream side of the FET 6, and a trapezoidal wave generating circuit 10 which generates such a trapezoidal wave that gradually increases from a ground potential to a reference voltage when the lamp 2 is turned on and gradually decreases from the reference voltage to the ground potential when the lamp 2 is turned off. A load current control circuit 20 controls the FET 6 so that the detected voltage value of a load current from the resistor 8 may become equal to that of trapezoidal wave signals. The load current flowing to the lamp 2 changes in a trapezoidal wave-like state when the lamp 2 is turned on and off and, therefore, the noise which is produced when the load current flowing to the lamp 2 rises can be suppressed by preventing the abrupt rise of the current when the lamp 2 is turned on.
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