The continuous scaling of very-large-scale integration technologies and the exponential growth of portable and high-performance computing systems have intensified the demand for digital arithmetic circuits that simultaneously achieve high speed, low power consumption, and robust reliability. Among these circuits, compressors play a pivotal role in arithmetic units such as multipliers, accumulators, and digital signal processors, where they significantly influence overall system performance and energy efficiency. This research article presents an in-depth theoretical and analytical investigation into low-power compressor architectures, focusing on 3-2, 4-2, and higher-order compressors as reported in foundational and contemporary literature. Drawing strictly from established references, this work synthesizes design philosophies based on CMOS logic, pass-transistor logic, XOR–XNOR gate optimization, multithreshold voltage schemes, and reduced transistor-count full adder structures. Rather than summarizing existing designs, the article elaborates extensively on the underlying principles that govern power dissipation, propagation delay, signal integrity, and scalability in compressor circuits. Methodological aspects are discussed from a conceptual design-analysis perspective, emphasizing transistor-level trade-offs without relying on equations or visual representations. The results section interprets reported outcomes in a descriptive manner, highlighting consistent trends across technologies and logic styles. The discussion critically evaluates limitations in prior approaches, such as voltage swing degradation and process variability sensitivity, while also exploring future design directions aligned with deep submicron and nanoscale technologies. The study concludes that low-power compressor optimization is not a single-technique problem but rather a holistic integration of logic style selection, threshold voltage engineering, and gate-level innovation. This article contributes a unified theoretical framework that can guide future compressor design for energy-efficient high-speed arithmetic systems.
