Experimental results on the current-mode WTA-MAX circuit with multi-chip capability

This paper presents experimental results on the current-mode WTA-MAX circuit with multi-chip capability. The circuit technique used is based on current replication, transport and comparison. Traditional techniques rely on the matching of an array of N transistors, where N is the number of system inputs. This implies that when N increases, the size of the circuit and the distance between transistors also increases, resulting in transistor matching degradation and loss of precision in the overall system performance. Furthermore, when multi-chip systems are required, the transistor matching is even worse and performance is drastically degraded. The circuit presented in this paper does not rely on the proper matching of N transistors; but on the precise replication of currents, performed by current mirrors with a limited number of outputs. Thus N can increase without degrading the precision, even if the system is distributed among several chips. Also, the different chips constituting the system can be of different foundries without degrading the overall system precision. Experimental results are presented that attest these facts