Ultra-low-voltage adder circuit design for smart sensor nodes in electrical vehicle applications

Abstract

Arithmetic addition is a major and fundamental operation in digital signal processing

DSP algorithms. Adders are one of the key computing components in DSP core and

accelerator designs [ 1]. Thus, arithmetic adder is the key circuit components

contributing major computation energy and creating a bottleneck in circuit

performance in vehicle sensor node systems. It is therefore essential to design a good

adder circuit to improve the overall performance of sensor node systems.

In order to design an adder, different adder algorithms are considered so as to

determine the suitable adder algorithm. Algorithms such as Radix-2 Kogge-Stone

Adder, Radix-4 Kogge-Stone Adder and Brunt-Kung Adder are discussed and

compared. The conclusion drawn from the comparison is that the Radix-2

Kogge-Stone Adder is an ideal addition algorithm to calculate large bits addition.

After choosing the adder algorithm, the next issue is transistor-level schematic

implementation. The whole adder algorithm can be constructed with logic gates.

With the implementation of each logic gate in adder algorithm, the transistor-level

schematic for the whole adder structure can be built through simulation.

The simulation results were derived from Mentor Graphics Modelsim simulation and

Cadence Virtuoso simulation. Mentor Graphics Modelsim simulation is to testify the

logic feasibility of the adder algorithm while Cadence Virtuoso simulation is used to

test the time delay of the adder circuit as to calculate the power consumption of the

adder designed.

When the adder is designed and simulated, the adder is needed to taken into electrical

vehicle application. First, an algorithm called Sum of Absolute Difference which is

used to calculate the vehicle speed is proposed. The sensor node architecture is

designed. Since arithmetic adders are the key computing components in sensor node

system, the Radix-2 Kogge-Stone Adder designed in this dissertation can be used to

improve the overall performance of the system.