Search

Sub-harmonic pulse injection-locked oscillators are becoming attractive candidates for the design of clock multipliers and as building blocks of phase-locked loops. Unfortunately, due to the large amplitude of the injected signals, these circuits cannot be analyzed with conventional methods and very-time-consuming simulations are needed to determine their phase noise performance. Phase-noise simulations are particularly critical when the ratio N between the output and the injection frequency gets large. To address the above issue, this paper provides an efficient computation flow to derive the phase noise of pulse injection-locked oscillators. The flow simply requires the computation of the phase-domain response and the phase noise of the free-running oscillator. An analytical expression, herewith demonstrated and compared against commercial simulation tools, allows calculating the phase noise of the injection-locked oscillator for any frequency ratio N. [ABSTRACT FROM AUTHOR]

This paper presents new design procedure for a general class-E power amplifier, here referred to as quasi-class-E, with finite dc-feed inductance and switch on-resistance and variable duty cycle under variable voltage switching (VVS), and variable derivative voltage switching (VDS), taking into account the switch breakdown voltage. It is shown that for non-zero switch on-resistance in class-E power amplifier, zero voltage switching (ZVS) and zero derivative switching (ZDS) conditions do not necessarily result in maximum efficiency. Hence, by assuming VVS and VDS, new design equations are derived. The new equations can be solved with a simple and fast numerical method in MATLAB. The theoretical results show efficiency improvement for quasi-class-E power amplifier compared to conventional designs. Circuit simulations confirm the validity of the theoretical results. [ABSTRACT FROM AUTHOR]

This paper presents a design-oriented analytical approach for predicting fast-scale instability in power electronics converters under voltage-mode control strategy. This approach is based on the use of the ripple amplitude of the feedback control voltage as an index for predicting subharmonic oscillations in these systems. First, the work revisits the stability analysis technique based on the nonlinear discrete-time model, demonstrating that the ripple amplitude can be included within the expression of the Jacobian matrix of this model, hence giving a mathematical support to extend the ripple index to more complex topologies. A simple but representative buck converter under voltage-mode control is used to illustrate the approach. Using the ripple-based index, closed-form expressions of stability boundaries are derived. Unlike other available results obtained from existing methods, the stability boundary, in this work is expressed analytically in terms of both power stage and controller design parameters. Moreover, one can determine how these parameters are involved in the closed form expressions and, furthermore, how each parameter affects the stability of the system. The approach is validated by numerical simulations from the state equations and also experimentally within a wide range of the design parameter space. [ABSTRACT FROM PUBLISHER]