An Asynchronous digital, Hysteretic Controller for an Automotive Application DC-DC Buck Converter

Abstract

This paper presents the analysis and the implementation details of using an asynchronous finite state machine (AFSM) as a controller for a voltage mode DC-DC BUCK converter used in automotive applications. The performance of the proposed Buck converter was analyzed using pre-silicon simulation results. The most notable aspects/parameters are highlighted by comparison with other implementations. The system has $\approx 180 ns$ reaction time and less than $1\mu s$ settle time with a $\pm 27\%$ output ripple variation over temperature and process. The ripple is fairly constant with the $Vo\ DC$ level that brings a 0.33% to 1.3% variation from 5V to 1.2V. The new controller concept offers more flexibility in choosing the external passive components. The proposed circuit was implemented in an 130nm BCD automotive technology.