A low-power, high-resolution WTA utilizing translinear-loop pre-amplifier

Abstract

This paper proposes a low-power, high-resolution Winner-Take-All (WTA) circuit basing on transistors in subthreshold operation. The WTA adapts a tree structure to reduce the effect of process variations. In addition to the traditional way of using positive feedback to improve the comparison performance, we propose to use translinear loop to amplify the difference between two inputs before comparison to achieve high resolution. The circuit has been fabricated with TSMC 0.35μm 2P4M process. The WTA operates with input current as low as a few nano amperes and resolution as high as 0.1%. Measurement results show that the circuit has a non-negligible offset. Discussions on the source of the offset with a proposed solution are also given. © 2010 IEEE.