Laszlo Huber

Single-stage, single-switch, isolated power supply technique with input-current shaping and fast output-voltage regulation for universal input-voltage-range applications

A new single-stage, single-switch, input-current shaping (S/sup 4/ICS) technique which combines the boost-like input-current shaper with a continuous-conduction-mode DC/DC output stage is described. In this technique, the boost inductor can operate in both the discontinuous and continuous conduction modes. Due to the ability to keep a relatively low voltage (<450 Vdc) on the energy-storage capacitor, this technique is suitable for the universal line voltage applications. The voltage on the energy-storage capacitor is kept within the desirable range by the addition of two transformer windings. The principle of operation of the S/sup 4/ICS circuit with forward DC/DC converter is presented. Experimental results obtained on a 100-W (5-V/20-A) prototype circuit are also given.

Performance Evaluation of Bridgeless PFC Boost Rectifiers

In this paper, a systematic review of bridgeless power factor correction (PFC) boost rectifiers, also called dual boost PFC rectifiers, is presented. Performance comparison between the conventional PFC boost rectifier and a representative member of the bridgeless PFC boost rectifier family is performed. Loss analysis and experimental efficiency evaluation for both CCM and DCM/CCM boundary operations are provided.

Design-oriented analysis and performance evaluation of clamped-current-boost input-current shaper for universal-input-voltage range

In cost-sensitive off-line applications, compliance with the existing line-current harmonic standards can be achieved by employing clamped-current-boost (CCB) input-current shapers (ICSs). In this paper, a thorough analysis of the CCB ICS is presented, and a complete design-oriented mathematical model is derived. The design equations are given in closed forms so that they can be easily computed by any standard mathematical software. The model is verified experimentally on a 100 W universal-input-voltage-range ICS.

Single-stage single-switch input-current-shaping technique with fast-output-voltage regulation

A new single-stage single-switch input-current-shaping (S/sup 4/ICS) technique, which combines the boost-like input-current shaper with a continuous-conduction-mode (CCM) DC/DC output stage, is described. In this technique, the boost inductor can operate in both the discontinuous conduction mode (DCM) and CCM. Due to the ability to keep a relatively low voltage (<450 V/sub DC/) on the energy-storage capacitor, this technique is suitable for the universal line-voltage applications. The voltage on the energy-storage capacitor is kept within the desirable range by the addition of two transformer windings. The principle of operation of the S/sup 4/ICS circuit with a forward DC/DC converter is presented. Experimental results obtained on a 100 W (5 V/20 A) prototype circuit are also given.

1.8-MHz, 48-V Resonant VRM: Analysis, Design, and Performance Evaluation

A detailed analysis of operation and a basic design procedure for a new high-frequency (HF) resonant-converter technology with phase-shifted regulation is presented. The new HF resonant technology has a good potential to be a cost-effective solution for the voltage regulation modules (VRMs) for the next generations of microprocessor systems. The new HF resonant technology is employed in the development of a 1.8-MHz, 48-V, 130-W (0.95–1.7 V, 100A) VRM. Experimental results are provided.

Implementation of open-loop control for interleaved DCM/CCM boundary boost PFC converters

This paper is focused on the implementation of the open-loop control method for interleaved DCM/CCM boundary boost PFC converters where the slave converter is synchronized to the turn-on instant of the master converter and both converters operate with current-mode control. It is shown that this method is the only open-loop control method that provides a stable operation. Implementations of the master-slave synchronization circuit in both analog and digital technology are described. Experimental results obtained on a 400-W, universal input, 400-V output prototype circuit with two interleaved DCM/CCM boundary boost PFC converters controlled by an integrated control circuit currently being developed are provided.

Design-Oriented Analysis and Performance Evaluation of Buck PFC Front-End

In universal-line ac/dc converters that require PFC, maintaining a high efficiency across the entire load range poses a major challenge. Typically, a boost PFC front-end exhibits 1-3% lower efficiency at 100-V line compared to that at 230-V line. It is shown in this paper that a buck PFC front end with an output voltage in the 80-V range can maintain a high-efficiency across the entire line range. A thorough analysis of the buck PFC converter operation and performance along with design optimization guidelines are presented. Experimental results obtained on a 90-W notebook adapter are provided.

Forward converter with current-doubler rectifier: analysis, design, and evaluation results

Complete steady-state analysis of a forward power converter with a current-doubler rectifier is provided. The advantages and disadvantages of this topology, as compared to the conventional forward power converter, are discussed. Step-by-step design guidelines are also outlined. Finally, experimental evaluation results obtained on a 3.3 V, 50 A DC/DC power converter prototype for the 40-60 V input-voltage range are presented.

Corona Discharge Surface Treater Without High Voltage Transformer

A corona discharge generator for surface treatment without the use of a step-up transformer with a high-voltage secondary is presented. The oil bath for high-voltage components is eliminated and still a reasonable volume, efficiency, and reliability of the generator are obtained. The voltage multiplication is achieved by an LC series resonant circuit. The resonant circuit is driven by a bridge type voltage-source resonant inverter. First, feasibility of the proposed method is proved by calculations. Closed form design expressions for key components of the electronic generator are provided. Second, a prototype of the electronic generator is built and efficiency measurements are performed. For power measurement, Lissajous figures and direct averaging of the instantaneous voltage-current product are used. The overall efficiency achieved is in the range between 80% and 90%.

Evaluation of AC VRM topologies for high-frequency power distribution systems

In this paper it is shown that the regulated series resonant rectifier (SRR) and series-parallel resonant rectifier (SPRR) with variable resonant capacitance are good candidates for AC voltage regulator modules (VRMs) in high-frequency power distribution systems with a sinusoidal AC bus. Control characteristics of the SRR and SPRR are derived using the sinusoidal approximation method. The effect of the transformer magnetizing inductance is also investigated. Experimental results obtained on a 5 V/8.5 A SRR with variable resonant capacitance designed for a 28 V/sub rms/, 1 MHz sinusoidal AC bus are provided.