| 摘要 |
PURPOSE:To obtain a synthesizing voltage having a small number of errors to a set value by inputting a differential input to a voltage and current converting circuit, supplying an inputted voltage to a power supply side through an arithmetic amplifier, and providing a feedback circuit in the arithmetic amplifier. CONSTITUTION:An input voltage Vr is supplied to an input terminal 13, and between input terminals 11, 12, a voltage Vd is supplied. The terminal 13 is connected to a positive input terminal of an arithmetic amplifier 1 and the terminals 11, 12 are respectively connected to bases of transistors Tr 28, 29. The Tr 28, 29 constitute a differential amplifier. A differential amplifying section by the Tr 28, 29 and resistances 26, 27 functions as a voltage and current converting circuit and transmits only a differential input component applied between the terminals 11, 12 to an output side. The amplifier 1 operates as a voltage follower and acts so as to make a connecting point of resistances have the same voltage as the terminal 13. According to the circuit costruction, respective voltages V1, V2 of output terminals 14, 15 are respectively represented by V1=Vr+Vd, V2=Vr-Vd, V1, V2 have no relation with respect to a direct current level of the terminals 11, 12 and an output having a small number of errors with respect to a set value can be obtained. |
