Design of high efficiency switching converters for mobile applications

Abstract

High power efficiency is a key design specification in mobile applications, mainly to increase battery life. To answer this need, switching converters are preferred in such applications to convert the battery voltage to voltage domains of various blocks. In this thesis, design improvements and novel solutions aiming to increase power efficiency and to enhance system performance for mobile platform switching converters are proposed for buck, boost, and buck-boost topologies. After a brief description of switching converter operation, a novel technique to improve power efficiency in buck converters is given, through optimized resistive and capacitive power losses of the output stage. Then, a charge recycling technique for single inductor dual output buck converters is described. Next, two improved control techniques for buck-boost converters based on hysteretic control and current mode control have been proposed. Finally, two novel techniques addressing the lock-out phenomenon occurring in boost and buck-boost converters are described. Simulation results show that the targeted performance improvements are achieved, thus demonstrating promising solutions for various future mobile platforms.