Logic system and circuit of ECL type - for logic linking of input signals, has two branches supplied by two constant current sources

摘要

The constant current sources have the same output currents, and the circuit has two branches. The branches consist of differential switching amplifiers connected in series with emitter coupled transistors. They are alternately made conducting or blocked in accordance with control signals applied to the differential amplifiers. A load resistor is provided for at least one transistor in each branch. It carries no current only if the AND conditions is satisfied for all input signals. Each input signal is operative simultaneously in all branches of the amplifiers connected in series, so that when the AND condition is not satisfied in all paths leading to the common load resistor, only one path is made conducting.