RLC circuit

About: RLC circuit is a research topic. Over the lifetime, 14490 publications have been published within this topic receiving 142697 citations.

Wireless power transmitter

Abstract: An example wireless power transmitter is configured for wirelessly transmitting a signal to a power receiving apparatus including a first resonance circuit and a load circuit. The first resonance circuit includes a power receiving coil and a first capacitor. The example wireless power transmitter includes a power supply that has a variable oscillation frequency and generates a signal having the oscillation frequency; a second resonance circuit that transmits the signal to the power receiving apparatus; a measuring unit that measures a signal reflection coefficient, the signal reflection coefficient being determined based on magnitude of the signal and magnitude of a signal reflected on the second resonance circuit to the power supply; and a controller that detects a value of the oscillation frequency making the signal reflection coefficient smaller than or equal to a threshold value, and calculates an electromagnetic coupling coefficient between the power transmission coil and the power receiving coil based on the detected value.

A Line Power-Supply for LED Lighting using Piezoelectric Transformers in Class-E Topology

Abstract: An up to 5 Watts wide range power supply LED driver demonstrator with a piezoelectric transformer (PT) has been built to show the static and dynamic behavior as an off-line power supply The target of the power converter controller using a PT, with 23 mm thickness and 17 mm diameter at frequency of 155-175 kHz, designed in a resonant circuit of class-E topology, is to maintain a constant output current of 290 mA/DC with variable output voltage drop at wide input voltage range of 85-250 V/AC Also, the ZVS (zero-voltage-switching) condition is achieved over the full operation range The used 1200 V fieldstop IGBT (1A-Type) shows losses around 200 mW over the full operating range for constant output current The paper shows the regulation method for off-line power supplies using PT in class-E topology in constant current mode regulation (CCMR) The regulation algorithm has been programmed in C language operated by a 32-bit DSP (TMS320F2812) Besides, in the class-E application, the duty cycle of the switching frequency needs to be controlled in order to achieve the ZVS during the operation at different load and input condition This goal is achievable only by phase locked loop (PLL) feedback in a satisfying way To solve this problem, the idea of PT with an auxiliary tap has been applied The application is suited for low size LED line adapters, to be integrated in bulb sockets The results are applicable for any controller design of resonant PT step-down topologies The several suited optimum control concept is investigated in this paper, considering the circuit expense being minimized

Solid state RF oscillator-detector for flow cytometer

Abstract: A junction field effect transistor (JFET) RF oscillator-detector circuit generates an RF signal for an apparatus for conducting electrical measurements of particles contained in a carrier fluid passing through an aperture in a cytometer flow cell The JFET oscillator includes a plurality of parallel-coupled JFETs having respectively different VDS vs IDS characteristics, that are biased to operate at square law detection regions of their respective VDS vs IDS characteristics One JFET operates in Class C mode, while the other operates in Class AB mode An RF resonant circuit is electrically coupled to the JFETs and to the measurement cell, and is operative to establish the frequency of an RF field applied to the measurement cell An RF load change detection circuit is coupled to the RF resonator circuit and is operative to detect an RF load change associated with a modification of the RF field as a result of a particle within the measurement cell aperture

Wireless communication circuit

Abstract: The invention includes a wireless communication circuit and a method of communicating with wireless signals that feature a tank circuit having an inductor connected in parallel with a capacitor circuit. The capacitor circuit includes a pair of capacitors coupled in series. Each of the capacitors is connected in common to ground and has a capacitive value associated. A feedback network is connected to selectively bias the tank circuit to produce a signal having an amplitude. The amplitude of the signal is a function of a ratio of the capacitive values associated with the capacitor circuit. The frequency of the signal is defined by the inductor and the capacitor circuit. The tank circuit is multifunctional in that it may be biased to function as a transmitter and a receiver.

Novel circuit designs and control techniques for high frequency electronic ballasts for high intensity discharge lamps

Abstract: The present invention provides an electronic ballast for a high intensity discharge lamp such as a metal halide lamp. The ballast includes an inverter and a resonant circuit with an ignition capacitor between the resonant circuit and the lamp. The ignition capacitor serves to provide the necessary start-up energy and also serves to provide a low impedance discharge path. A single ignition capacitor may be sufficient, but if a long cable is used to connect the lamp to the ballast, then two ignition capacitors in parallel at opposite ends of the cable may be used. The ballast further provides means for monitoring and controlling lamp power by monitoring a nominally constant dc link voltage, and means for detecting short-circuit and open circuit conditions. A retrial mechanism is provided in the event of the lamp failing to ignite that includes a temporary disabling of the inverter in order to keep the rms lamp voltage low.