This document surveys power optimization techniques for low-power VLSI circuits in deep submicron CMOS technology, emphasizing the importance of managing leakage power which can comprise up to 50% of total power consumption. It discusses various optimization methods across different abstraction levels, including system, algorithm, architecture, gate, and transistor levels, highlighting strategies such as voltage scaling, transistor stacking, and dual Vdd configurations. The paper concludes with an overview of specific techniques to reduce both static and dynamic power dissipation in modern VLSI designs.