Output impedance

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

High-Performance Bridge Modular Switched-Capacitor Converter With Small Component Requirement Based on Output Impedance Analysis for Low Loss

Abstract: In this paper, a novel multilevel bridge modular switched-capacitor converter is proposed for the application in high voltage gain. Compared with the conventional switched-capacitor converters, it utilizes fewer components (switching device and capacitor) to obtain the same voltage conversion, as well as some advantages including low total power device rating, output capacitor requirement, and low output voltage ripple. In order to illustrate its superiority, an output impedance analysis method is developed, which can comprehensively evaluate a two-phase switched-capacitor converter's steady-state performance by judging its output impedance. The simple formulation developed not only permits optimization of the capacitor sizes to meet several constraints such as a total capacitance or total energy storage limit, but also permits optimization of the switch sizes subject to constraints on total switch conductance or total switch volt-ampere products. Consequently, the output impedance under the optimizations has contributed to the comparison of the latest switched-capacitor converters. As a result, the performance (based on conduction loss) of the proposed converter is proved to be optimum in fast-switching-limit impedance and does well in slow-switching-limit output impedance as well. Simulation and experimental results have validated the principle and properties of this converter and the analysis method.

Harmonic termination of power amplifiers using BAW filter output matching circuits

Abstract: A system, apparatus and method for providing filtering functionality and impedance transformation within a BAW resonator network are disclosed. In particular, a BAW resonator network is designed to provide bandpass capability and a transformation between its input impedance and output impedance. By effectively integrating impedance matching functionality within the BAW resonator network, discrete impedance matching elements previously required within a system may be removed or reduced in size. As a result, matching networks and their associated component costs, insertion losses, and board size contributions may be reduced. Harmonic termination may be provided within the BAW resonator network or a prematch stage to improve efficiency of a power amplifier.

Low-Voltage Wilson Current Mirrors in CMOS

Abstract: In this paper, we describe three simple low-voltage CMOS analogs of the Wilson current mirror that function well at all current levels, ranging from weak inversion to strong inversion. Each of these current mirrors can operate on a low power-supply voltage of a diode drop plus two saturation voltages and features a wide output-voltage swing with a cascode-type incremental output impedance. Two of the circuits requires an input voltage of a diode drop plus a saturation voltage while the third one features a low input voltage of a saturation voltage. We present experimental results from versions of these three current mirrors that were fabricated in a 0.5-mum CMOS process through MOSIS, comparing them with CMOS implementations of the conventional Wilson and super-Wilson current mirrors.

Animal shock collar with low impedance transformer

Abstract: A remote receiver unit is for use in an animal behavior modification system that applies an electrical shock to an animal. The remote receiver unit has an electrical shock device including two electrodes configured for contacting the animal, a source of alternating current voltage, and an electrical transformer with a primary coil and a secondary coil. The primary coil is electrically connected to the source of alternating current voltage. The secondary coil is electrically connected to at least one of the two electrodes. The transformer has an output impedance of less than 900 ohms. A receiver circuit is electrically connected to the shock device. The receiver circuit is configured for activating the shock device in response to a received signal.

The Control Strategy for the Grid-Connected Inverter Through Impedance Reshaping in q -Axis and its Stability Analysis Under a Weak Grid

Abstract: The grid-connected inverter is the vital energy conversion device in renewable energy power generation. With the increasing installed capacity of renewable energy, the grid presents characteristics of weak grids with large grid impedance. In general, the inverter often obtains grid synchronization information by the phase-locked loop (PLL) and to suppress the background harmonic and amplitude disturbance of grid voltage, the grid voltage feedforward (GVF) control is also needed. However, previous researches revealed that the PLL and the GVF would shape the quadrature-axis ( $\boldsymbol {q}$ -axis) output impedance of the inverter into a negative resistance in the low-frequency band, and this would be responsible for the instability of the inverter under a weak grid. To resolve this instability issue, this article proposes an impedance controller for reshaping the $\boldsymbol {q}$ -axis impedance into a positive resistance in the low-frequency band, which eliminates the negative effect introduced by the PLL and the GVF; therefore, the inverter will operate under very weak grids. Moreover, the proposed control strategy is only for $\boldsymbol {q}$ -axis impedance reshaping, and it does not affect the output characteristics of $\boldsymbol {d}$ -axis, thus ensuring the ability of the inverter to suppress background harmonics and amplitude disturbance of the grid voltage. The conclusions are verified by experimental results.