Improving Accuracy of the Current Mirrors for High-Resolution Applications

This paper proposes a reliable approach to remove mismatch of the current sources in the current-mode DACs. Specifically, design of a novel dynamic single-stage current-mode comparator with an offset cancellation mechanism based on the bulk-controlled technique, is presented. The study focuses on the application of this concept to a 4-bit current-mode DAC for the sake of simplicity. Simulation results through HSPICE in a standard 0.18
$\mu \mathrm{m}$
CMOS technology prove that not only the proposed structure is capable to provide high-resolution currents for applying on the current-mode DACs, but also generates more accurate currents for high resolution applications such as image sensors and analog to digital converters. Notably, the total power consumption of the proposed structure is 140
$\mu \mathrm{W}$
with the power supply of 1.8 V. Furthermore, the proposed offset cancellation circuit demonstrates a settling time of 1.6
$\mu \mathrm{s}$
and occupies a compact active area of
$30\times 34\mu \mathrm{m}^{2}$
, make it suitable to integration with highly compact circuits as well as practical implementations.