Voltage regulator (VR) design optimization is subjective. This dissertation addresses optimality conditions related to conventional and new topologies. It is argued that VR optimization is a tradeoff between cost and efficiency. While transient performance is critical to the feasibility of a design, it should be regarded as a constraint and not a variable in the optimization problem. New concepts, Cost-per-Watt and efficiency norms, are proposed that provide metrics to compare the optimality of competing VR solutions, such as new multiphase buck topologies that use coupled inductor output filters and extended duty ratio mechanisms. The conclusion of this dissertation is that the Coupled Inductor Extended Duty Ratio Buck Converter is the most advantageous VR topology. It is as efficient as a conventional multiphase buck but much less expensive. The new topology is a feasible all ceramic output capacitor solution, since it requires 1/3 the amount of capacitance as a typical multiphase buck. This dissertation also describes problems and solutions for using multi-winding coupled inductors in multiphase buck output filters. A new losses DCR inductor current sense scheme is proposed for multi-winding coupled inductors that accurately captures both the transient and steady state behaviors. It is also shown that multi-winding coupled inductors can demonstrate instability for large coupling coefficients. Stability conditions for designing multi-winding coupled inductors are provided. Lastly, modeling and control of VRs is addressed. Large signal models for conventional and extended duty ratio buck converters are proposed that accurately capture the dynamics during large load changes and changes in the duty ratio. The dissertation also describes the multi-objective VR control problem. Voltage regulation, load line regulation, and current balancing can be achieved using the proposed control frameworks, which decouple three control objectives. Overall, this dissertation provides significant contributions, from topologies to control, for state of the art microprocessor voltage regulators.Input voltage division and output current division are advantageous circuit techniques in a VR architecture. The switched capacitors of the extended duty ratio converter divide the input voltage. In many VRs the input voltage is at least 12V;anbsp;...
|Title||:||Voltage Regulator Optimization Using Multi-winding Coupled Inductors and Extended Duty Ratio Mechanisms|
|Author||:||Bradley S. Oraw|
|Publisher||:||ProQuest - 2008|