Design of a Low Power and High Speed Comparator using MUX based Full Adder Cell for Mobile Communications

Abstract

This paper presents an implementation of comparator (1-bit) circuit using a MUX-6T based adder cell. MUX-6T full adder cell is designed with a combination of multiplexing control input and Boolean identities. The proposed comparator design features higher computing speed and lower energy consumption due to the efficient MUX-6T adder cell. The design adopts multiplexing technique with control input to alleviate the threshold voltage loss problem which is commonly encountered in Pass Transistor Logic (PTL) design. The proposed design successfully embeds the buffering circuit in the full adder design which helps the cell to operate at lower supply voltage compared with the other related existing designs. It also enhances the speed of the cascaded operation significantly while maintaining the performance edge in energy consumption. In the proposed design, the transistor count is minimized. For performance comparison, the proposed MUX-6T comparator (1-bit) is compared with four existing full adders based comparators using BSIM4 model parameters. The simulations are performed for 65nm process models indicate that the proposed design has lowest energy consumption along with the performance edge in both speed and energy consumption. The variants namely area and power of the proposed comparator is also compared with the published author designs to validate its suitability for low power and high speed mobile communication applications.

Low Power 11T Adder Comparator Design

“…Due to the input nodes transients, the MCIT-7T adder cell based circuit consumes high power [12]. The large power consumption and low speed are the main drawbacks of the MUX-12T design [13]. It is due to buffering restoration unit at AB in the carry circuit.…”

Design Wallace Tree Multiplier Using Reversible Gates

“…Follow up with the previous explanation to understand how this complete adder works. There is a difference in operation when using the second multiplexer of a complete adder [16]. Below, carry bits are used as inputs to the second multiplexer.…”