IMPROVEMENTS IN OR RELATING TO DIFFERENTIAL AMPLIFIERS

摘要

1286602 Transistor differential amplifiers SIEMENS AG 28 Aug 1970 [29 Aug 1969] 41439/70 Heading H3T A monolithic integrated circuit differential amplifier comprises a first pair of closely adjacent transistors T3, T4 of one conductivity type having collector loads consisting of a second pair of closely adjacent transistors T1, T2 which are lateral type and of opposite conductivity to the first pair, the second pair being controlled by an auxiliary differential amplifier comprising a further pair of transistors T5, T6 of the same conductivity as the first pair, the arrangement being such that differential inputs (at E1, E2) produce a single ended output UA. It is explained that with equal inputs the collector currents of T3, T4 must be equal and there is no current through load resistor RL, but without the auxiliary differential amplifier T5, T6 the symmetry would be upset by the base currents of T1, T2 (which would be connected to K1) unless the gain of T1, T2 were unobtainably high.