FAULT WARNING IN ELECTRONIC SENSORS

摘要

An output stage for an electronic sensor including two transistors connected in series to a junction therebetween to form a push/pull arrangement relative to a pair of supply lines provided with fixed supply voltages that are different for each line that are connected with different ones of the two transistors. The junction between the two transistors being connected to a sensor output line. Each of the transistors is driven by a respective drive line from an amplifier which receives an input signal corresponding to a sensor input signal. A fault detecting circuit is provided which includes circuitry to detect an open circuit fault condition in either of the two fixed voltage supply lines to disconnect the signal drive line leading to the associated one of the two transistors which is connected to the respective supply line that has been detected to have an open circuit fault. This disconnecting of the drive line from the associated transistor prevents back feed from the sensor output line from being coupled back to through the transistor and its drive line to the electronic sensor.