Power sensitivity—a new method to estimate power dissipation considering uncertain specifications of primary inputs

ABSTRACT

Power dissipation in CMOS circuits heavily depends on the signal properties of the primary inputs. Due to uncertainties in specification of such properties, the average power should be specified between a maximum and a minimum possible value. Due to the complex nature of the problem, it is practically impossible to use traditional power estimation techniques to determine such bounds. We present a novel approach to accurately estimate the maximum and minimum bounds for average power using a technique which calculates the sensitivities of average power dissipation to primary input signal properties. The sensitivities are calculated using a novel statistical technique and can be obtained as a by-product of average power estimation using a Monte Carlo based approach. The signal properties are specified in terms of signal probability (probability of a signal being logic ONE) and signal activity (probability of signal switching). Results show that the maximum and minimum average power dissipation can vary widely if the primary input probabilities and activities are not specified accurately.

REFERENCES

• 1: R.Burch, F.Najm, P.Yang and T.Trick, "A Monte Carlo Approach for Power Estimation", IEEE Trans. VLSI Systems, Vol.1, No. 1, pp. 63-71, March, 1993.
• 2: Z. Chen, K. Roy, and T.-L. Chou, "Sensitivity of Power Dissipation to Uncertainties in Primary Input Specification," Custom Integrated Circuits Conference, pp. 487-490, 1997.
• 3: Tan-Li Chou , Kaushik Roy , Sharat Prasad, Estimation of circuit activity considering signal correlations and simultaneous switching, Proceedings of the 1994 IEEE/ACM international conference on Computer-aided design, p.300-303, November 06-10, 1994, San Jose, California, United States
• 4: A. Ghosh , S. Devadas , K. Keutzer , J. White, Estimation of average switching activity in combinational and sequential circuits, Proceedings of the 29th ACM/IEEE conference on Design automation, p.253-259, June 08-12, 1992, Anaheim, California, United States
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INDEX TERMS

Primary Classification:
  B. Hardware
  B.7 INTEGRATED CIRCUITS
      B.7.1 Types and Design Styles
          Subjects: Memory technologies

Additional Classification:
  C. Computer Systems Organization
  C.3 SPECIAL-PURPOSE AND APPLICATION-BASED SYSTEMS
      Subjects: Signal processing systems

  F. Theory of Computation
  F.1 COMPUTATION BY ABSTRACT DEVICES
      F.1.2 Modes of Computation
          Subjects: Probabilistic computation

  I. Computing Methodologies
  I.5 PATTERN RECOGNITION
      I.5.4 Applications
          Subjects: Signal processing

General Terms:
Design, Experimentation, Measurement, Performance, Theory

Keywords:
CMOS circuits, CMOS logic circuits, Monte Carlo based approach, logic CAD, maximum bounds, minimum bounds, power dissipation estimation, power estimation, power sensitivity, primary inputs, signal probability, signal properties, signal switching, statistical technique, uncertain specifications