電気測定器の信号入力回路

Signal input circuit for electric measurement apparatus

Abstract

【課題】 直流領域から交流領域にかけてほぼ一定のゲインを示す低雑音・低バイアス電流・低オフセットの信号入力回路を提供する。 【解決手段】 少なくとも一方がボルテージフォロワの非反転型の第1オペアンプA21と第2オペアンプA22とをCR時定数回路を介して接続してなり、第1オペアンプA21に測定信号が入力されるオフセット補償回路20と、第1,第2オペアンプA21,A22からの出力信号を受けて動作する一対のFET1,FET2を有する差動増幅回路10と、差動増幅回路10に接続された出力用第3オペアンプA1とを含み、一方のFET1のゲートを第1オペアンプA21の非反転入力端子に接続し、他方のFET2のゲートを第2オペアンプA22の非反転入力端子に接続する。 【選択図】 図1
PROBLEM TO BE SOLVED: To provide a signal input circuit with low noise, low bias current and low offset, the gain of which is almost constant from a DC region to an AC region. SOLUTION: The signal input circuit for electric measurement apparatuses includes: an offset compensation circuit 20 wherein first and second operational amplifiers OA21, OA22 at least either of which employs a noninverting type of voltage follower are connected via a CR time constant circuit and a measurement signal is given to the first operational amplifier A21; a differential amplifier circuit 10 including a pair of FETs 1, 2 activated by receiving output signals from the first and second operational amplifiers A21, A22; and an output purpose third operational amplifier A1 connected to the differential amplifier circuit 10, and configured such that the gate of the one FET 1 is connected to the noninverting input terminal of the first operational amplifier A21, and the gate of the one FET 2 is connected to the noninverting input terminal of the second operational amplifier A22. COPYRIGHT: (C)2005,JPO&NCIPI

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Cited By (2)

    Publication numberPublication dateAssigneeTitle
    JP-2016038219-AMarch 22, 2016アルプス・グリーンデバイス株式会社, Alps Green Devices Co Ltd電流センサ
    WO-2007017483-A1February 15, 2007Siemens AktiengesellschaftElectronic circuit