Abstractapplied to a wide range of power circuits that includes the resonant type converters. The basic limitation in resonant The method of state-space averaging has been successfully converters is that these circuits have state variables that exapplied to pulse-width modulated power converters, but has hibit predominantly oscillatory behavior. This paper investiits limitations with switched circuits that do not satisfy a gates a more general averaging scheme that can, in principle, accomodate arbitrary types of waveforms. The method is small ripple" condition. This work considers a more general accomodate arbitrary types of waveforms The method is small ripple" condition. This work considers a more general based on a time-dependent Fourier series representation for a averaging procedure that encompasses state-space averaging "sliding window" of a given waveform. For example, for an and is potentially applicable to a much broader class of cir-arbitrary time-domain waveform x(o), the method considers cuits and systems. In particular, the technique is shown to the Fourier coefficients of x(s) for s E (t -T, t] at the time be effective on a number of examples including resonant type instant t. Simplifying approximations can be made by omitconverters.ting insignificant terms in this series. For instance, to recover the traditional state-space averaged model, one would retain only the DC coefficient in this averaging scheme.

Analysis methods are developed that fully determine a switched-capacitor (SC) dc-dc converter's steady-state performance through evaluation of its output impedance. This analysis method has been verified through simulation and experimentation. The simple formulation developed permits optimization of the capacitor sizes to meet a constraint such as a total capacitance or total energy storage limit, and also permits optimization of the switch sizes subject to constraints on total switch conductances or total switch volt-ampere (V-A) products. These optimizations then permit comparison among several switched-capacitor topologies, and comparisons of SC converters with conventional magnetic-based dc-dc converter circuits, in the context of various application settings. Significantly, the performance (based on conduction loss) of a ladder-type converter is found to be superior to that of a conventional magnetic-based converter for medium to high conversion ratios.

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Abstract-This paper discusses the presence of steady-state limit cycles in digitally controlled pulse-width modulation (PWM) converters, and suggests conditions on the control law and the quantization resolution for their elimination. It then introduces single-phase and multi-phase controlled digital dither as a means of increasing the effective resolution of digital PWM (DPWM) modules, allowing for the use of low resolution DPWM units in high regulation accuracy applications. Bounds on the number of bits of dither that can be used in a particular converter are derived. Finally, experimental results confirming the theoretical analysis are presented.

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