Negative impedance converter

About: Negative impedance converter is a research topic. Over the lifetime, 5801 publications have been published within this topic receiving 87636 citations.

Impedance measurement circuit

Abstract: A protection circuit for a defibrillator that prevents a defibrillator pulse from being generated if the impedance between the defibrillator's electrode leads is not characteristic of the impedance between a pair of defibrillator electrodes properly connected to the defibrillator. The impedance measuring circuit applies a current to the electrode leads and the resulting voltage is measured to provide an indication of the electrode's impedance. The current is applied between the electrodes at about 33 kHz to approximate the impedance between a pair of defibrillator electrodes during a defibrillation pulse. The output of the measurement circuit is converted to an 8 bit word by an analog-to-digital converter and read by a microprocessor which compares the measured impedance to various impedance values in order to either generate an enable signal for the defibrillator or display messages indicative of open or short circuited electrode leads or a patient monitoring electrode connected to the electrode leads. The impedance measurement circuit operates in either of two ranges which are selected by the microprocessor on the basis of the measured impedance values.

Circuit for supplying electric load such as fan or storage battery of vehicle from solar generator

Abstract: A power supply circuit for an electric load (2) like a fan or battery in a car driven off a solar generator (1) has impedance matching between the solar generator and a DC converter (6) in front of the load. There is a control member (18) which can short out the converter depending on the value of at least one operational parameter during a regime when the converter losses are expected to be higher than the losses caused by the mismatch if the load is coupled directly to the solar generator. The converter is a pulse-width modulated (PWM) step-down converter. It has a switching transistor between input and output and another across the output terminals.

Impedance simulating circuit for transmission lines

Abstract: A circuit for simulating the presence of positive or negative impedances in shunt or in series with a transmission line. A voltage generating circuit generates an impedance simulating voltage and introduces that voltage in series with the transmission line. A current generating circuit generates an impedance simulating current and introduces that current in shunt with the transmission line. Current feedback circuitry controls the voltage generating circuitry in accordance with the amplitude of the signal current in the transmission line to simulate either a positive or negative series impedance. Voltage feedback circuitry controls the current generating circuitry in accordance with the signal voltage across the transmission line to simulate either a positive or negative shunt impedance. Circuitry is also provided to afford these simulated impedances in the presence of echo suppressing and impedance matching characteristics.

Differential to single-ended converter

Abstract: A differential to single-ended converter includes a voltage-to-current converter that converts differential voltage input signals to differential current signals which differ by a difference current. A current mirror mirrors the first differential current signal. A substantially constant DC voltage level is established. A resistor conducts any difference in current between the mirrored current and the second differential current signal and translates this difference current to a single-ended voltage output signal. An input buffer provides the differential voltage input signals to the voltage-to-current converters.

DC-DC converter and storage apparatus

Abstract: A DC-DC converter includes N capacitors having identical capacitances, initially coupled in series, and supplied with an external power supply voltage to be charged thereby, and an circuit for coupling the N capacitors in parallel and varying a duty ratio of a charging timing, so as to vary an internal power supply voltage which is output from the DC-DC converter.