Screen Orientation Aware DRAM Architecture for Mobile Video and Graphic Applications

Abstract

The state-of-the-art mobile image and graphic applications demand not only a lot of computing power, but also high-quality memory services. Moreover, depending on the screen orientations of mobile systems, image and graphic data can be accessed in a complicated manner. Since conventional dynamic random access memories (DRAMs) do not provide successive image and graphic pixels on the same column address, however, they achieve extremely poor throughput, long latency, and high power consumption in any screen orientation of mobile systems. This paper presents a novel DRAM efficient for both portrait and landscape screen orientations of mobile systems. We develop a simple, but effective two-transistor, one-capacitor memory cell that can be activated not only by a row activation command like a conventional DRAM memory cell, but also by a new column activation command. Next, the proposed DRAM architecture makes all the new memory cells on the same row address, or the same column address successively accessed. Finally, new DRAM commands and operations that are completely compatible with the conventional DRAMs are presented. Experimental results show that the proposed DRAM has 3.6% larger area, but achieves 5.8% higher memory utilization, and 14.8% shorter memory latency, on average. In addition, it consumes 4.4% less memory power than the conventional DRAM, on average.