CIRCUIT FOR CONVERTING A TEMPERATURE DEPENDENT INPUT SIGNAL TO A TEMPERATURE INDEPENDENT OUTPUT SIGNAL

摘要

A bridge circuit for combination with a variable resistance sensor whose resistance may vary as a function of a sensed variable and also as a function of a parasitic variable such as, for example, temperature. The bridge circuit includes at least one variable resistance which varies as a function of the parasitic parameter and is relatively insensitive to the sensed parameter. The bridge circuit comprises a first leg incorporating the sensor resistor having a tap junction whose voltage varies as a function of the sensed parameter and of the parasitic parameter, a second leg including the parasitic parameter responsive resistance and having a voltage tap whose voltage varies only as a function of the parasitic parameter and a third leg interconnecting the first and second leg voltage taps and having a signal tap whose voltage varies only as a function of the sensed parameter. In a preferred embodiment, a resistance type exhaust gas sensor whose resistance varies as a function of the partial pressure of oxygen in the exhaust system of an internal combustion engine and also as a function of the temperature of the environment of the exhaust system is compensated by the circuit of the present invention to remove temperature dependency effects.