Low-Power and High-Speed Advantages of DRAM-Logic Integration for Multimedia Systems

Takao WATANABE  Ryo FUJITA  Kazumasa YANAGISAWA  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E80-C   No.12   pp.1523-1531
Publication Date: 1997/12/25
Online ISSN: 
DOI: 
Print ISSN: 0916-8516
Type of Manuscript: INVITED PAPER (Special Issue on Low-Power and High-Speed LSI Technologies)
Category: 
Keyword: 
DRAM-integrated chip,  embedded DRAM,  computer graphics,  main memory,  

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Summary: 
The advantages of DRAM-logic integration were demonstrated through a comparison with a conventional separate-chip architecture. Although the available DRAM capacity is restricted by chip size, the integration provides a high throughput and low I/O-power dissipation due to a large number of on-chip I/O lines with small load capacitance. These features result in smaller chip counts as well as lower power dissipation for systems requiring high data throughput and having relatively small memory capacity. The chip count and I/O-power dissipation were formulated for multimedia systems. For the 3-D computer graphics system with a frame of 12801024 pixels requiring a 60-Mbit memory capacity and a 4.8-Gbyte/s throughput, DRAM-logic integration enabled a 1/12 smaller chip count and 1/10 smaller I/O-power dissipation. For the 200-MIPS hand-held portable computing system that had a 16-Mbit memory capacity and required a 416-Mbyte/s throughput, DRAM-logic integration enabled a 1/4 smaller chip count and 1/17 smaller I/O-power dissipation. In addition, innovative architectures that enhance the advantages of DRAM-logic integration were discussed. Pipeline access for a DRAM macro having a cascaded multi-bank structure, an on-chip cache DRAM, and parallel processing with a reduced supply voltage were introduced.