Output impedance

About: Output impedance is a research topic. Over the lifetime, 11185 publications have been published within this topic receiving 134949 citations.

Equivalent circuit modeling of LLC resonant converter

Abstract: LLC resonant converter is widely used in industry. However, up to now, no simple and accurate small-signal equivalent circuit model is available. This paper proposes an equivalent circuit model of LLC resonant converter. The simple equivalent circuit model is derived based on modification and simplification of extended describing function method. The model can well predicts the small-signal behaviors observed in LLC resonant converter, whenever switching frequency is below, close to or above the resonant frequency. For the first time, analytical expressions for control to output voltage, input to output voltage, input impedance and output impedance are provided to aid close loop feedback design. Simplis simulation and experimental results are presented to prove the accuracy of the model.

Electrical Impedance: Principles, Measurement, and Applications

Abstract: Basics Two-terminal circuit elements Resistors, capacitors, inductors Phasors Impedance and admittance Power and RMS value Beyond two-terminal networks Impedance and linear response theory Impedance as an electromagnetic quantity The graphical representation of electrical impedance Density quantities Frequency ranges Impedance definitions n-terminal definitions n-terminal-pair definitions Change of definition Cable effects Devices and appliances of interest in impedance measurement Generators Voltage and current measurement Voltage and current ratio devices Cables and connectors Shielding Common practice methods I-V method Two-voltage methods Three-voltage method Bridges Transformer bridges Beyond 2T definition of impedance standards The LCR meter Calibration Resonance methods Mutual inductance measured as self-inductance Network analysis Going digital Sampling Direct digital synthesis Digital signal analysis Digital impedance bridges Sampling impedance meters Some applications of impedance measurement Measurement of electromagnetic properties of materials Sensor reading Semiconductor device characterization Biological measurements Metrology: traceability and uncertainty Traceability Uncertainty Metrology: standards Impedance standards Inductance standards Capacitance standards Synthesized impedance standards Cryogenic standards Standards of phase angle, time constant, etc Open and short standards High-frequency and microwave standards Metrology: realization and reproduction The International System of Units Realization of impedance units Reproduction of the ohm Counting electrons The future of SI Appendices SI Harmonic electromagnetic fields CODATA recommended values Reactance Chart Nomenclature Bibliography Index

Optimum Design of Asymmetrical Multisection Two-Way Power Dividers With Arbitrary Power Division and Impedance Matching

Abstract: A general analysis and design procedure is developed for the asymmetrical multisection power divider with arbitrary power division ratio and arbitrary specifications of input and output impedance matching over any desired frequency bandwidth. The even- and odd-mode analysis, which was previously applied to the design of multisection Gysel power dividers, required that the unequal power division ratios be accompanied with appropriately proportional output impedances. This requirement is relaxed here. The equivalent circuits are first obtained for the divider and then their scattering parameters are determined. Some error functions are then constructed by the method of least squares. Their minimization determines the geometrical dimensions of the optimum divider. An approximate method based on the even and odd modes is developed for its initial design of the divider. Two examples of single- and double-section dividers are designed. Their frequency responses of isolation and transmission coefficients are obtained by the proposed method, HFSS software, fabrication, and measurement. They agree within the approximate assumptions. A two-section and two-way power divider is designed and fabricated by the proposed method for the case of unequal port impedances in the L-band. The measured isolation between the outputs is better than -22 dB in 44% of the band.

Grounded capacitor current mode single resistance-controlled oscillator using single modified current differencing transconductance amplifier

Abstract: This study proposes a current mode canonical single resistance-controlled oscillator (SRCO) circuit based on a single modified current differencing transconductance amplifier. The circuit employs grounded capacitors and provides a current output with high output impedance. The proposed circuit also enables orthogonal control of frequency and oscillation condition. The performance of the proposed SRCO is verified by means of simulation program with integrated circuit emphasis (SPICE) simulations, on-chip experiments and measurements.