A MODULAR CURRENT-MODE HIGH-PRECISION WINNER-TAKE-ALL CIRCUIT

Traditional Winner-Take-All (WTA) circuits rely on the matching of an array of N transistors, where N is the number of inputs of the WTA [1] , [2]. This implies that when N increases, also increases the size of the WTA and the distance between the transistors that have to match, w hich yields to transistor matching degradation and loss of precision i n the overall WTA circuit performance. Furthermore, when multi-chip WT A's are required, transistor matching is even worse, and the performan ce is drastically degraded. In this paper we present a WTA circuit tec hnique, based on current mode principles, that does not rely on matchi ng of a transistor array. The operation of the circuit depends on curr ent transport and replication bg local current mirrors with a small nu mber of outputs. Thus N can increase and the precision is not degraded , not even if the WTA is disbrituted among several chips. Even more, t he different chips that constitute the WTA can be of different foundri es, and the precision of the WTA is not drastically degraded. Simulati on results on these facts are provided.