Test Asynchronous FIR Filter Design

Test Asynchronous FIR Filter Design Presenter: Po-Chun Hsieh Advisor:Tzi-Dar Chiueh Date: 2003/12/1

Outline • Low Power Issue of Asynchronous Circuits • Test FIR Design - Logic circuits - Multiplier - FIR Architecture • Future work • Conclusion • Reference

Low Power Issue of Asynchronous Circuits • No global clock • Functions work only when needed • Dynamic Logic and Domino Logic

Asynchronous FIR filter and other Asynchronous Modules • Every component of FIR works in each evaluation • For other modules, functions work only when needed

Low power Filter • Logic circuits • Multiplier • FIR Architecture

Computation Units • 4-phase handshaking is easier to design • Req in is low  clean the content  “done” is low • Req in is high evaluate “done” is high

Dynamic Logic and Domino Logic • Match the requirements for Computation Unit • No spontaneous transitions, low power • Drawbacks • Must be Monotonous Inputs • Completion Detection Methods

Problem of Bounded delay method • How to design delay element ?

Problem of activity-monitoring completion-detection (AMCD) method (1/2) • Test the transitions at important points • Used in Single-rail CMOS Logic [1]

Problem of activity-monitoring completion-detection (AMCD) method (2/2) • When used in dynamic (domino) logic, maybe it will never pull down the signal [2]

Differential Cascode Voltage Switch Logic (DCVSL) • Dual-rail Domino Logic gate • Drawbacks: Area、Power consumption • Completion detection method only add in the output cascode stages

Low power Logic gate • Single-rail bounded-delay dynamic (domino) logic gates are very low power, but have two problems • Before finding solutions, choose to use DCVSL

Asynchronous Multiplier • Multiplier is the most important part in a FIR filter • Sign and Magnitude [5]

Data Dependent Carry Save Adder Array (1/2) • MD: Multiplicand; MR: Multiplier; PP: Partial Product [3]

Data Dependent Carry Save Adder Array (2/2) • 4X4 Carry Save Adder array • By probability, only turn on 50% adders [4]

Partially work by DCVSL Logic • If MR(n)=“1” ( MR(n).t=“1”; MR(n).f=“0”; ) then the adder cell works • If MR(n)=“0” ( MR(n).t=“0”; MR(n).f=“1”; ) then the adder cell will not work

FIR Architecture • H: Handshake Circuit; h(0)~h(N): coefficients

Future Work • Test the designed FIR module • Search for low power FIR architecture and Multiplier • Try to find solutions to the problems of single-rail dynamic (domino) logic

Conclusion • Unlike other kinds of Asynchronous circuits, every component of FIR works every time. • Choose FIR architecture, Multiplier, and Implement Circuits to make FIR low power.

Reference [1] Grass, E. and S. Jones, "Activity-monitoring completion-detection (AMCD): a new approach to achieve self-timing", Electronics Letters, vol. 32, no. 2, pp. 86-88, January 1996 [2] Bartlett, V.A. and E. Grass, "Completion-detection technique for dynamic logic,"Electronics Letters, vol. 33, no. 22, pp. 1850-1852, October 1997. [3]Bartlett, V. A. and E. Grass, “A Self-Timed Multiplier using Condutional Evaluation", Proc. PATMOS'98, 8th International Workshop on Power, Timing, Modelling, Optimization and Simulation, Lyngby, Denmark, pp.429-438, October 1998 [4] D.Kearney and N.W.Bergmnn, “Bundled Data A syncheonous Multipliers with Data Dependent Computation Times”,Proc. ASYNC’97, 2nd Int.Symp. On Advanced Research in Asynchronous Circuits and Systems,pp. 186-197,1997 [5] Bartlett, V. A. and E. Grass, “A Low-Power Asynchronous VLSI FIR Filter", Proc. ARVLSI'01, 19th Conference on Advanced Research in VLSI, Salt Lake City, Utah, USA, March 2001.

Test Asynchronous FIR Filter Design