Feasibility Study of a High Temperature Dc-dc Converter Employing V2 Control Architecture

Abstract

This body of work demonstrates the feasibility of implementing the V2 control architecture in SOS in the design of a step-down DC-DC converter for high temperature (200C) applications. A model for the step-down DC-DC converter employing V2 control architecture has been developed in Orcad Pspice. The SPICE model also includes the implementation of soft-start, under-voltage lockout, over-current protection and 100% duty cycle comparator. The model takes into consideration the design issues involved with variation with temperature and is shown to work from room temperature to around 200C. The developed model is utilized to suggest the minimum performance metrics of the individual building block components in the design of the DC-DC converter over the room temperature to 200C temperature range. This study includes a detailed analysis of the workings of the V2 architecture along with the design equations involved. The effects of temperature variation on analog and digital circuit components have been discussed in detail along with the impact of processes variations on the individual circuit components in the design of the feedback. Various circuit topologies for both the OTA and comparators are reviewed and suggested implementations provided. A selection criterion for appropriate circuit topologies best suited to meet the V2 architecture performance metrics has also been provided. Finally an iterative design algorithm has been developed for the design of a step-down DC-DC converter employing V2 feedback mechanism. The algorithm is documented in a step-by-step procedure starting with DC-DC performance specifications of individual component or block behavior design variables are in turn specified resulting in the design of the specified DC-DC converter.