DIAGNOSING CIRCUIT AND METHOD TO DETERMINE ELECTRIC CURRENT FLOWING IN SENSOR BY AMPEROMETRIC TITRATION

摘要

PURPOSE: To provide a diagnosing circuit to determine an electric current flowing in a sensor by amperometric titration. ;CONSTITUTION: A diagnosing circuit is provided with an electric current source (V+) 46 to flow a direct current to a sensor 41, a switching means 45 to selectively operate its electric current source, a comparing means 42 to generate a control signal D by comparing an electric potential difference between both ends of the sensor with reference voltage, a control means 44 to control the swiching means 45 in response to its control signal D and timing means 48 and 49 to supply an output signal 50 to show an average value of an electric current flowing in the sensor 41 by measuring accumulative time when a swiching signal Q has a first logical level during a selected time interval.;COPYRIGHT: (C)1995,JPO