Transistor circuit capable of deliver- ing, independently of the load, an output current proportional to the difference between two voltages

Claim 1

A CIRCUIT ARRANGEMENT FOR SUPPLYING AN OUTPUT CURRENT TO A LOAD CIRCUIT WHICH IS PROPORTIONAL TO THE DIFFERENCE BETWEEN FIRST AND SECOND INPUT VOLTAGES, SAID CURRENT BEING SUBSTANTIALLY INDEPENDENT OF LOAD IMPEDANCE VARIATIONS WITHIN PREDETERMINED LIMITS, SAID CIRCUIT COMPRISING COMPARISON MEANS HAVING FIRST AND SECOND INPUT MEANS AND AN OUTPUT CIRCUIT FOR DERIVING A DEVIATION SIGNAL, MEANS FOR SUPPLYING SAID FIRST AND SECOND VOLTAGES TO SAID FIRST AND SECOND INPUT MEANS, RESPECTIVELY, COMPENSATOR MEANS HAVING AN OUTPUT CIRCUIT AND AN INPUT CIRCUIT COUPLED TO SAID COMPARISON MEANS OUTPUT CIRCUIT AND RESPONSIVE TO SAID DEVIATION SIGNAL FOR PRODUCING AN OUTPUT CURRENT IN SAID COMPENSATOR MEANS OUTPUT CIRCUIT, MEANS FOR CONNECTING SAID LOAD CIRCUIT IN SERIES BETWEEN SAID COMPENSATE MEANS OUTPUT CIRCUIT AND ONE OF SAID INPUT MEANS THEREBY TO SUPPLY A CORRECTION SIGNAL TO SAID COMPARISON MEANS, MEANS FOR SUPPLYING A FLOATING SUPPLY VOLTAGE TO SAID COMPENSATOR MEANS CONTROLLED BY SAID DEVIATION SIGNAL, SAID SUPPLYING MEANS COMPRISING A DIRECT CURRENT SOURCE OF SUPPLY VOLTAGE COUPLED TO SAID COMPENSATOR MEANS, FIRST AND SECOND TRANSISTORS CONNECTED IN SERIES ACROSS SAID VOLTAGE SOURCE TO PROVICE A COMMON EMITTERCOLLECTOR PATH AND A COMMON JUNCTION THEREBETWEEN AND EACH HAVING A CONTROL ELECTRODE, MEANS FOR COUPLING SAID DEVIATION SIGNAL FROM THE OUTPUT CIRCUIT OF SAID COMPARISON MEANS TO THE CONTROL ELECTRODES OF SAID FIRST AND SECONF TRANSISTORS, AND MEANS FOR CONNECTING THE COMMON JUNCTION IN THE SAID COMMON EMITTER-COLLECTOR PATH OF SAID FIRST AND SECOND TRANSISTORS TO A FIXED POTENTIAL.