The Design of Current Memory Elements Based on the Mathematical Tool of Linear Algebra
The fundamentals of the design of memory elements (ME) for storing current digital signals are considered. A non-traditional methodology for the synthesis of MEs based on the mathematical tool of linear algebra is proposed. Linear equations and CMOS circuitry of the main types of current MEs are presented. It is shown that the logic elements (LE) suitable for constructing two-valued MEs are schemes realizing linear analogues of the “Sheffer stroke” operations (2OR-NOT), “dual stroke” (2AND-NOT), “inhibition on x2”, “implication from x1 to x2”, “modulo 2 sums” or “logical equivalence operations”, which are synthesized using truncated difference and comparison logic-arithmetic operations. It is established that the comparison operation requires larger element costs for circuit implementation, than a “truncated difference” operation, but it has better accuracy characteristics. In this case, the circuits of the LE of one type can differ in the directions of the input and output currents (“sink” or “source”). It is recommended to use the considered LEs as the basic components of twovalued current trigger circuits. Besides, the linear analogues of the “dual stroke” and “inhibition on x<sub>2</sub>” operations, which are recommended for use in the construction of two-valued MEs has the simplest circuit realization. Schematic implementations of “comparison” and “Sheffer stroke”, “dual stroke”, “inhibition on x2” operations based on differential stages (DS) and special "folded" cascodes, performing the function of converting the input current quanta into the differential voltage of the DC are investigated. The main area of application of the considered current memory elements is the processing of sensor signals with current output, as well as specialized digital information processing devices in which the application of traditional potential LEs is difficult, or is associated with a deterioration in reliability in severe operating conditions. Microchips with the considered principle of operation are not currently produced.