Input-output characteristic measuring method of the analog circuit including an input-output characteristic measuring apparatus and an operational amplifier of an analog circuit including an operational amplifier

摘要

PPROBLEM TO BE SOLVED: To readily obtain an adjusted value (value of resistance) for adjusting the offset and gain of output signal of operational amplifier, and based on the adjusted value, to be deletable an adjusting circuit element (resistor), prepared preliminarily so as to make the offset and the gain concerned as the target value. PSOLUTION: A plurality of known voltages VF are impressed on a circuit 302 to be measured through a power source for measurement 304, and, on this occasion, the output voltage VSBLEV_M/SBof a level converter (operational amplifier) 120, the output voltage VSBCTI/SBof a PWM/analog transducer 90a, and the supply voltage VSBcc/SB1 supplying offset current of the level converter 120 are measured with the first to the third voltage-measuring sections 306 to 308. An operation section 310 derives the input/output characteristics of the level converter 120 and input/output characteristics subsequent to the output side of the level converter 120 side from each of the correlation relations of these measured values, and the adjusted value is determined so as to make the offset and the gain of the level converter 120 as the target value. PCOPYRIGHT: (C)2008,JPO&INPIT