公开(公告)号：JPH04315043A

公开(公告)日：1992-11-06

申请号：JP34448791

申请日：1991-12-26

Applicant: MARELLI AUTRONICA

Inventor： CHIESARIIO CHIANCHI ,  FURANKO SARERUUNO

IPC: F02B77/08 ,  F02D41/14 ,  F02D41/24 ,  G01N27/406 ,  G01N27/409 ,  H03F3/45

Abstract: PURPOSE: To obtain an interface circuit for single power supply oxygen sensor having small pin count and requiring no external calibration by providing a voltage/current converter having one input terminal to be connected with a sensor, and an amplifier to be connected with the output part of the converter. CONSTITUTION: An interface circuit IC comprises a voltage/current converter V/I having two input terminals A, B to be connected with an oxygen sensor S, and an amplifier TDA to be connected with the output part of the converter V/I. The converter V/I is a differential circuit having two output terminals producing current signals Ii of same magnitude but opposite polarity at the operation. The magnitude Vi/Ri is proportional to the voltage Vi between the input terminals A, B of the converter V/I. The amplifier TDA is a high gain Rm drift-free differential amplifier having two input parts being connected with the output part of the converter V/I, and two output terminals producing a potential difference Vd proportional to the magnitude of output current from the converter V/I in operating.