Output impedance

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

A new, improved CMOS realization of CDTA and its filter applications

Abstract: This paper presents a high-performance current differencing transconductance amplifier (CDTA), a re- cently reported active element, especially suitable for analog signal processing applications. A high linearity CMOS configuration for a CDTA is made up of high linearity input and output stages. The proposed CDTA provides high output impedance at port X and excellent input/output current tracking. A biquad filter cir- cuit was chosen as an application example in order to demonstrate the performance of the CDTA. PSpice simulation results using a TSMC 0.35-μ m CMOS process model were included to verify the expected values.

A superconducting thermal switch with ultrahigh impedance for interfacing superconductors to semiconductors.

Abstract: A number of current approaches to quantum and neuromorphic computing use superconductors as the basis of their platform or as a measurement component, and will need to operate at cryogenic temperatures. Semiconductor systems are typically proposed as a top-level control in these architectures, with low-temperature passive components and intermediary superconducting electronics acting as the direct interface to the lowest-temperature stages. The architectures, therefore, require a low-power superconductor/semiconductor interface, which is not currently available. Here we report a superconducting switch that is capable of translating low-voltage superconducting inputs directly into semiconductor-compatible (above 1,000 mV) outputs at kelvin-scale temperatures (1 K or 4 K). To illustrate the capabilities in interfacing superconductors and semiconductors, we use it to drive a light-emitting diode in a photonic integrated circuit, generating photons at 1 K from a low-voltage input and detecting them with an on-chip superconducting single-photon detector. We also characterize our device’s timing response (less than 300 ps turn-on, 15 ns turn-off), output impedance (greater than 1 MΩ) and energy requirements (0.18 fJ m−2, 3.24 mV nW−1). A superconducting switch that is capable of translating low-voltage superconducting inputs directly into semiconductor-compatible outputs at kelvin-scale temperatures could provide a superconductor-to-semiconductor logical interface for future quantum and neuromorphic computing architectures.

Noninvasive Online Parametric Identification of Three-Phase AC Power Impedances to Assess the Stability of Grid-Tied Power Electronic Inverters in LV Networks

Abstract: This paper presents a noninvasive online parametric identification of three-phase ac power impedances to assess small-signal stability of grid-tied inverter systems by using well-known impedance-ratio-based stability criteria. The identification technique is integrated into the control of an existing grid-tied inverter for the estimation of wide bandwidth ac grid impedances, on top of its original power conversion function. This is accomplished in practice by injecting a short-time small-signal pseudorandom binary sequence (PRBS), a digital approximation of white noise which is wide bandwidth in nature, on the inverter control loop so that all frequencies of interest at the impedance measurement point can be excited at once. Then, digital processing is performed in the integrated control platform where the parametric ac grid impedance is extracted from the measurement of voltage and current over the length of PRBS injection. Moreover, a procedure on how to identify the output impedance of the inverter is deployed so that the parametric source and load impedances can be used to verify the system stability by means of the generalized Nyquist stability criterion. The technique is validated via hardware-in-the-loop real-time simulation. This paper focuses on the identification of balanced three-phase ac impedances in dq reference frame and a dq diagonal-dominant stability analysis which is typical of low-voltage distribution grids.

High frequency surgical generator comprising an additional transformer

Abstract: An HF surgical appliance comprising an HF generator having an output circuit, which contains an output transformer and has an output impedance. Output terminals, to which an HF surgical instrument can be connected, are provided, said instrument supplying a high-frequency current with a specific frequency into tissue to treat the same. An additional output circuit containing an additional transformer, which is connected between the output circuit and the output terminals to reduce the output impedance is also provided. In this way, the HF surgical appliance can be operated with a high power output even on loads having low impedance.

Current mode allpass/notch and bandpass filter using single CCII

Abstract: A current mode second-order allpass notch and bandpass filter using a single CCII, two grounded capacitors and four resistors is proposed. The allpass and notch output current signals, taken out through port z of a CCII and having high output impedance, can be obtained by tuning a resistor in the proposed network. The resonance angular frequency and quality factor of the new network have the advantages of low passive sensitivities and are insensitive to the current tracking error of the nonideal CCII.