Digitally Controlled Low-Power Hybrid SMPS

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Switch-mode power supplies (SMPS) are highly efficient power processing devices providing regulated voltage or current for virtually all electric devices today. Dc-dc and ac-dc low-power (LP) SMPS, processing power from a fraction of watt to several hundreds of watts are widely used in computers, communication devices, portable electronics, and numerous other applications. For example, in modern cell phones more than 20 different SMPS supply various functional blocks. In those applications, the LP SMPS are among the largest contributors to the overall volume and the weight of the device. As such, they are one of the main obstacles in further minimization of the devices. Most of this volume, by far, is taken by the inductors and capacitors of the SMPS. The size of these reactive components is dictated by topological limitations and requirements for high power processing efficiency. The existing LP SMPS almost exclusively rely on fairly basic 2-switch and 4-switch power stage topologies, such as buck, boost, and their simple derivations. These topologies put stringent physical limits on the possibilities for the minimization of reactive components and for efficiency improvements. The dominance of these fairly rudimentary topologies is a direct consequence of the traditional use analog controllers in LP SMPS. The analog solution provide simple and cost-effective implementation but are ill-suited for the regulation of advanced converter topologies with a larger number of switches or/and operating modes, which provide more possibilities for volume reduction and efficiency improvements. This is mostly due to very limited ability of inflexible analog controllers to implement multi-mode control laws required for regulation of more advanced topologies. The ultimate goal of this research is to develop new topological and complementary control solutions that will overcome existing physical limitations and allow further minimization of the LP SMPS. To achieve the main goal, the new generation of supplies, named hybrid SMPS, will combine several different power transfer and processing techniques, which are usually used separately, inside a single power converter structure.