Frequency-analog sensor for physical magnitudes - has integrated injection logic oscillator, with injection current control integrated measuring resistor

摘要

The sensor is partic. intended for detaching a pressure, a temp., a force, or a light intensity. It has an oscillator circuit and a measuring resistor as a feeler, influencing the frequency of the oscillator circuit output signal, the resistor being changed by the detected physical magnitude. The oscillator (24) is of a ring type, produced in integrated injection logic technique. The measuring resistor (21) is so monolithically integrated with the ring oscillator on a semiconductor chio (15) that the injection current of the oscillator is controlled by the resistor. Pref. the latter is of temp.-dependent type. In order to form such a resistor thesemiconductor chip may be doped with an impurity of specified concentration, affecting an m- or p-conductivity, this doping being restricted to a certain region of the chip. A photoresistor may be thus formed.