Design Method of High Performance and Low Power Functional Units Considering Delay Variations

• WATANABE Kouichi

  Research Center for Advanced Science and Technology, the University of Tokyo

• IMAI Masashi

  Research Center for Advanced Science and Technology, the University of Tokyo

• KONDO Masaaki

  Research Center for Advanced Science and Technology, the University of Tokyo

• NAKAMURA Hiroshi

  Research Center for Advanced Science and Technology, the University of Tokyo

• NANYA Takashi

  Research Center for Advanced Science and Technology, the University of Tokyo

Abstract

As VLSI technology advances, delay variations will become more serious. Delay-insensitive asynchronous dual-rail circuits tolerate any delay variation, but their energy consumption is more than double that of the single-rail circuits because signal transitions occur every cycle in all bits regardless of the input bit pattern. However, in functional units, a significant number of input bits may not change from the previous input in many cases. In such a situation, calculation of these bits is not required. Thus, we propose a method, called unflip-bits control, makes use of the above situation, to reduce energy consumption. We evaluate the energy consumption and performance penalty for the method using HSPICE and the verilog-XL simulator, and compare the method with the conventional dual-rail circuit and a synchronous circuit. Our evaluation results reveal that the proposed asynchronous dual-rail circuit has a 12-60% lower energy consumption compared with a conventional asynchronous dual-rail circuit.

Journal

• IEICE transactions on fundamentals of electronics, communications and computer sciences

  IEICE transactions on fundamentals of electronics, communications and computer sciences 89 (12), 3519-3528, 2006-12-01

  The Institute of Electronics, Information and Communication Engineers

Keywords

• delay variation
• dual-rail asynchronous circuit
• functional unit
• unflip-bit control

Details

• CRID: 1571417127545052416
• NII Article ID: 110007537855
• NII Book ID: AA10826239
• ISSN: 09168508
• Text Lang: en
• Data Source:
  • CiNii Articles