A RISC microcontroller based voltage regulator module with fuzzy logic controller for processor core in mobile systems

Designing digitally controller voltage regulation modules (VRM) for mobile computing devices requires careful selection of components, choosing of a proper circuit topology and finally adopting a control scheme that will produce response figures conforming to the requirements laid down by the target processor manufacturer. This process is complicated by several factors that lead to making tradeoffs between efficiency, voltage ripple and dynamic response. Passive and active components selection is made in conformity with the performance figures required by the target processor power requirements along with compatibility with the dynamic voltage scaling (DVS) scheme adapted by the processors under investigation. A Choice of a suitable intelligent control scheme must be made that would suffice the stability and dynamic response requirements of power supply specifications set by the design requirements of the target processor. This paper describes the design of Buck converter that has a fuzzy controller implemented using a RISC based microcontroller from Atmel Atmegaxx series along with a choice of hardware components that will ensure better efficiency while delivering good stability and a dynamic response that complies with the requirements of the target processor. System simulation was carried out using a model realized using Simulink\Matlab. Simulation results showed that the fuzzy controller has the capability of providing response characteristics that makes it comparable with PID controllers, more appropriate for implementation in an application requiring variable output voltage and more apt for implementation using microcontrollers.