A novel soft switching crossing current resonant converter (XCRC)

Unlike other resonate or soft-switching converter, this novel topology employs only two switches and a very simply control method. The inherent constant power protection feature is another merit. No special resonate chip is needed to control the circuit. By adding two diode parallel with the dividing capacitors and selecting the capacitors for a small value that will fully charge and discharge in one cycle, one can obtain the zero voltage switching characteristic and control the output voltage regulation by frequency modulation. An industrial standard PWM chip can be easily modified to a VCO as the control element.published_or_final_versio

A novel soft-switching double modulation converter (DMC)

This paper introduces a new and simple power converter topology by which both the amplitude and the duty cycle are modulated to achieve soft switching characteristic in a standard half bridge configuration. This novel double modulation power converter (DMC) is able to provide zero voltage switching and nonpulsating input ripple current. Constant switching frequency, simple control and gate drive circuit makes the DMC an ideal power converter to fill the low to medium power application gap in which the soft switching phase modulation method is costly to apply. The DMC is also applicable to full bridge circuits for higher power output. An offline 1 MHz 50 W DMC is built which demonstrates the high efficiency and the compactness of the power converter.published_or_final_versio

A novel high frequency current-driven synchronous rectifier applicable to most switching topologies

A novel current-driven synchronous rectifier is presented in this paper. With the help of current sensing energy recovery circuit, the proposed current-driven synchronous rectifier can operate at high switching frequency with high efficiency. Compared with those voltage-driven synchronous rectification solutions, this current-driven synchronous rectifier has several outstanding characteristics. It can be easily applied to most switching topologies like an ideal diode. Constant gate drive voltage can be obtained regardless of line and load fluctuation. This makes it desirable in high input range application. Converters designed with this synchronous rectifier are also capable of being connected in parallel without taking the risk of reverse power sinking. Principle of operation is given in the paper. A series of experiments verify the analysis and demonstrate the merits.published_or_final_versio

Practical solutions to the design of current-driven synchronous rectifier with energy recovery from current sensing

Current-driven synchronous rectifier with current sensing energy recovery has been proved to be suitable for almost all high frequency switching topologies. The synchronous rectifier can be driven on and off automatically according to the current direction. In fact it can be taken as an active diode with very low power dissipation. Some theoretical analysis and experimental results have been shown in the previous work. This paper presents an extended analysis to some practical considerations when applying this current-driven synchronous rectifier in switching converter design.published_or_final_versio

A single phase voltage regulator module (VRM) with stepping inductance for fast transient response

A single-phase fast transient converter topology with stepping inductance is proposed. The stepping inductance method is implemented by replacing the conventional inductor in a buck converter by two inductors connecting in series. One has large inductance and the other has small inductance. The inductor with small inductance will take over the output inductor during transient load change and speed up dynamic response. In steady state, the large inductance takes over and keeps a substantially small ripple current and minimizes root mean square loss. It is a low cost method applicable to converters with an output inductor. A hardware prototype of a 1.5-V dc-dc buck converter put under a 100-A transient load change has been experimented upon to demonstrate the merit of this approach. It also serves as a voltage regulator module and powers up a modern PC computer system. © 2007 IEEE.published_or_final_versio

Current-driven synchronous rectification technique for flyback topology

For low voltage, high current application, synchronous rectification technique can help improve efficiency in a flyback converter. This paper investigates some technical challenges within a synchronous rectification flyback converter. One of the major problems is that the discontinuous current mode (DCM) operation is not achievable with a control-driven or self-driven synchronous rectifier. Continuous current mode operation may introduce excessive RMS current and circulation energy at light load or high line condition. To solve this problem, we propose to use an energy recovery current-driven synchronous rectifier for flyback topology. Analysis and experiments demonstrate the performance of this approach.published_or_final_versio

Analysis of buck-boost converter inductor loss using a simpleonline B-H curve tracer

A simple method to plot online B-H curves and calculate the core loss of the inductor in a conventional buck-boost power converter is developed. In order to obtain a reliable loss data, measurement error and phase shift error are analyzed and then quantified. A new method to minimize measurement error is given. A new core loss model in terms of switching duty cycle is presented. This model predicts variation of core loss of an inductor operating in various conditions in a switching converter. This inductor model can be generalized to inductors in other switching converter topologies.published_or_final_versio

General impedance synthesis using simple switching converters

A general impedance synthesizer using a minimum number of switching converters is studied in this paper. We begin with showing that any impedance can be synthesized by a circuit consisting of only two simple power converters, one storage element (e.g., capacitor), and one dissipative element (e.g., resistor) or power source. The implementation of such a circuit for synthesizing any desired impedance can be performed by (i) programming the input current given the input voltage such that the desired impedance function is achieved; (ii) controlling the amount of power dissipation (generation) in the dissipative element (source) so as to match the required active power of the impedance to be synthesized. Then, the instantaneous power will automatically be balanced by the storage element. Such impedance synthesizers find a lot of applications in power electronics. For instance, a resistance synthesizer can be used for power factor correction (PFC), a programmable capacitor or inductor synthesizer (comprising of small high-frequency converters) can be used for control applications.published_or_final_versio

A Constant Power Battery Charger Circuit with Inherent Soft Switching and PFC

A battery charger circuit is proposed which operates as a constant power source by means of discontinuous operation of the two half bridge dividing capacitors. Its input characteristic is resistive and input harmonic current content can meet international regulation. Soft switching is also accomplished by paralleling two diodes across two dividing capacitors. A 12 V 65 W prototype was built to demonstrate the merit of this topology.link_to_subscribed_fulltex

Electro-Magnetic Interference (EMI) Due to Non Conducted Coupling Paths in Switching Mode Converter

A simplified model which takes into account minimum coupling paths (MCP) for a switching mode power converter is presented. A minimum number of coupling capacitors are found which connect between all three terminals of a LISN and nodes of a converter circuit. Simulation that shows both inductive and capacitive coupling mechanisms may contribute substantial noise at the input.link_to_subscribed_fulltex