Integrable conversion circuit for converting input voltage to output

Abstract

An integrable conversion circuit for linearly converting an input voltage applied to the circuit with the high potential of a DC power source taken as a reference to an output current or voltage with high accuracy. The circuit includes first and second PNP transistors whose bases are connected to each other. The first transistor has its base and collector connected together. The emitter of the first transistor is connected to one end of a first input resistor, and an input voltage source is connected between the other end of the first input resistor and the high potential supply terminal of a DC power source. A second resistor is connected between the emitter of the second transistor and the high potential supply terminal of the DC power source. First and second constant current sources, which provide equal constant currents, are connected between the collector of the first transistor and a low potential supply terminal of the DC power source and between the collector of the second transistor and the low potential supply terminal, respectively. A third transistor of NPN-type has its collector connected to the connection point between the emitter of the second transistor and a second input resistor, and its base connected to the connection point between the collector of second transistor and the second constant current source. An output current proportional to the input voltage is drawn from the emitter of third transistor.