VLSI Design of a flexible-structure Sequential Mixed-signal Neural processor


Authors:  Jordi Madrenas, Eduard Alarcón, Jordi Cosp and J.Manuel Moreno


Journal/Conference: Proceedings of the 6th International Conference Mixed-Signal Design of Integrated Circuits and Systems (MIXDES'99), Kraków (Poland), June1999, pp. 259.

Abstract - A mixed-signal circuit that can emulate multi-layer perceptron neural networks is presented. The sequential processing provides a tradeoff between speed, power consumption and circuit area, allowing a flexible accommodation of different network structures. The design of the three most critical analog basic blocks of the processor is presented. a) Dynamic analog memories: A technique of switching error cancellation is proposed. b) Semialgorithmic DAC multipliers. They perform an analog-digital product., so the network parameters are stored in digital form. c) Sigmoid circuit. A winner-take-all based sigmoid circuit is used to fulfill the system requirements. The common-mode currents are cancelled by means of a common-mode feedback. Concerning the digital part, a general-purpose programmable digital control circuit with a high degree of circuit control flexibility is presented. Finally, the results and ongoing work are discussed.