Low Power Deep Sub Micron Cmos Logic

Low-Power Deep Sub-Micron CMOS Logic

1. 1 Power-dissipation trends in CMOS circuits Shrinking device geometry, growing chip area and increased data-processing speed performance are technological trends in the integrated circuit industry to enlarge chip functionality. Already in 1965 Gordon Moore predicted that the total number of devices on a chip would double every year until the 1970s and every 24 months in the 1980s. This prediction is widely known as "Moore's Law" and eventually culminated in the Semiconductor Industry Association (SIA) technology road map [1]. The SIA road map has been a guide for the in dustry leading them to continued wafer and die size growth, increased transistor density and operating frequencies, and defect density reduction. To mention a few numbers; the die size increased 7% per year, the smallest feature sizes decreased 30% and the operating frequencies doubled every two years. As a consequence of these trends both the number of transistors and the power dissi pation per unit area increase.In the near future the maximum power dissipation per unit area will be reached. Down-scaling of the supply voltage is not only the most effective way to reduce power dissipation in general it also is a necessary precondition to ensure device reliability by reducing electrical fields and device temperature, to prevent device degradation. A draw-back of this solution is an increased signal propa gation delay, which results in a lower data-processing speed performance.

Low Power Deep Sub-micron CMOS Logic

Power Management of Digital Circuits in Deep Sub-Micron CMOS Technologies

In the deep sub-micron regime, the power consumption has become one of the most important issues for competitive design of digital circuits. Due to dramatically increasing leakage currents, the power consumption does not take advantage of technology scaling as before. State-of-art power reduction techniques like the use of multiple supply and threshold voltages, transistor stack forcing and power gating are discussed with respect to implementation and power saving capability. Focus is given especially on technology dependencies, process variations and technology scaling. Design and implementation issues are discussed with respect to the trade-off between power reduction, performance degradation, and system level constraints. A complete top-down design flow is demonstrated for power gating techniques introducing new design methodologies for the switch sizing task and circuit blocks for data-retention and block activation. The leakage reduction ratio and the minimum power-down time are introduced as figures of merit to describe the power gating technique on system level and give a relation to physical circuit parameters. Power Management of Digital Circuits in Deep Sub-Micron CMOS Technologies mainly deals with circuit design but also addresses the interface between circuit and system level design on the one side and between circuit and physical design on the other side.