Current-mode CMOS-based multiple-radix adder circuit using minimum-redundantly represented positive-digit value

We discuss a new current-mode CMOS based parallel processing adder circuit for multiple-radix number. In this paper, a new current-mode addition algorithm for multiple-radix number with the minimum, positive redundant code representation is proposed, where only one positive redundant sign “r” which is the same value as that of the radix exists. Furthermore, to realize the new addition circuitry, we propose a newly designed CMOS based threshold detector with which it is possible to control the threshold current value. We constructed a new multiple-radix adder circuit which is CMOS transistor-oriented and works in the current mode operation. The adder circuit is more compact when the value of radix becomes higher than existing circuits. The operation characteristics of the adder circuit is simulated by using the general circuit simulation software, SPICE. The SPICE model parameters of the enhancement type PMOS and NMOS transistors are based on 0.8 μm MOSIS CMOS technology. We confirm the performance of the circuit and evaluate it in terms of the circuit size and the processing speed