Series-coupled emitter coupled logic (ECL) circuit having a plurality of independently controllable current paths in a lower plane

摘要

Emitter-coupled logic (ECL) circuit employs differential amplifiers arranged in upper and lower planes and selectively controlled by respective groups of input signals. Each differential amplifier of the upper plane has the emitters of its transistors connected to the collector of a transistor in one branch of the differential amplifier of the lower plane. Additional parallel connected transistors provide an OR function of several input signals in the upper plane for each of the differential amplifiers of that plane and the input signals of the lower plane are applied to each differential amplifier of the upper plane, with the exception of the input signal associated with the branch of the lower plane differential amplifier associated with a particular upper plane differential amplifier.