Integrated circuit two terminal temperature transducer

Abstract

An integrated circuit two terminal temperature transducer providing an accurate current output that is linearly related to absolute temperature over an extended temperature range. The circuit is of the type using first and second transistors having conductive areas of different sizes, and control transistors for supplying equal currents through the first and second transistors to operate them at different current densities, and a resistor responsive to the base-to-emitter voltages of the first and second transistors for developing currents therethrough proportional to absolute temperature. Improved accuracy over an extended temperature range is provided in a two terminal device by means of a third transistor coupled to the first and second transistors to generate another controlled current varying linearly with absolute temperature to be combined with the currents through the first and second transistors to form an output current. Bias currents used by control transistors are directed through the third transistor to compel the bias currents to become components of the controlled current. Similarly, the integrated circuit substrate is connected to direct the substrate leakage current through the third transistor to compel the leakage current to become a component of the output current. Accordingly, bias current and substrate leakage current do not erroneously affect the output current.