Xor-Dotting and Select-Dotting in DCS Logic
Original Publication Date: 1988-Jan-01
Included in the Prior Art Database: 2005-Feb-14
DCS is a differential cascode logic circuit also referred to as differential current switch logic illustrated in Fig. 1. It consists of a current source (transistor 11), a 2-level logic tree (transistors 1-6), emitter followers (transistors 7-8 for sending signals to upper inputs of other circuits), and level shifters (transistors 9-10 for sending signals from other circuits to lower inputs). (Image Omitted) Logic is performed in the logic tree. The lower level is controlled by a true/complement pair of signals, S and -, channeling current into the S (6) or the - (3) path. The upper left pair (1 and 2) is controlled by the pair of signals -/A, while the upper right pair (4 and 5) is controlled by -/B.