| 摘要 |
PROBLEM TO BE SOLVED: To obtain a circuit capable of self-adjusting the output impedance of a circuit by inputting a driver output signal, an output impedance part output signal and first/second reference voltages and outputting a control signal so as to set output impedance, based on the driver output signal and the control signal. SOLUTION: When the output voltage of an input impedance control circuit part 401 becomes higher than reference voltage Vref+, a level detection part 402 executes negative feedback control so as to raise the output impedance of the part 401. Thus, the output of the part 401 can be controlled to be equal to the reference voltage Vref+ while driving a load 102. Since reflected waveform returning after being fully reflected by a digital receiver farthest from a digital driver circuit 101 becomes voltage of about 2.Vref+ in the output of the circuit 101, the part 402 easily detect it to control the output impedance.
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