Richard Redl

Optimizing the load transient response of the buck converter

The optimized gain of the voltage-error amplifier and current-mode control provide instantaneous transient response and small DC shift of the output voltage for step changes in the load current. This paper analyzes the system, determines the best compensation, provides design guidelines for buck converters powering Pentium(R) II processors and presents results of simulations and experiments.

An economical single-phase passive power-factor-corrected rectifier: topology, operation, extensions, and design for compliance

This paper describes a novel passive power-factor correction circuit that ensures the compliance of the capacitively filtered single-phase rectifier with the EN61000-3-2 norm at a cost much lower than the known solutions. The circuit can be used to about 300 W. The additional components are a small inductor, a small capacitor and a diode.

Reducing distortion in peak-current-controlled boost power-factor correctors

At light load and/or high line, the peak-current-controlled boost power-factor corrector has considerable distortion. In this paper, the authors determine the line-current waveform and the distortion of the corrector, the shape of the ideal reference signal, and discuss and analyze three distortion-reducing methods. The distortion-reducing methods are: (1) adding a variable DC offset to the sinusoidal reference; (2) predistorting the sinusoidal reference with a nonlinear network; and (3) converting the peak-current-control scheme into a simplified average-current-control scheme. The paper presents analyses, practical considerations, and experimental results.

A new high-frequency and high-efficiency electronic ballast for HID lamps: topology, analysis, design, and experimental results

A new high-frequency and high-efficiency electronic ballast for high-intensity discharge (HID) lamps is presented. The ballast features an integral resonant ignitor, high efficiency, power regulation, and optional hot strike and fast warm-up capabilities. The ballast can operate virtually any lamp without acoustic arc resonance. The paper presents the topology, operation, analysis, design considerations, and experimental results obtained from a 70 W prototype.

Switched-noise filter for the buck converter using the output ripple as the PWM ramp

Buck converters using the output ripple as the PWM ramp have low circuit complexity and fast transient response but are sensitive to external noise due to the small ripple amplitude. This paper proposes the switched noise filter to reduce the noise sensitivity

Insulated-gate-transistor drivers for soft-switching converters, synchronous rectifiers, and ZVS/ZCS active snubbers

A new family of ICs for driving insulated-gate transistors is introduced. Three members of the family are designed for soft-switching converters and converters with synchronous rectifiers; two members are designed for converters with zero-voltage-switching or zero-current switching active snubbers. Due to their low stand-by current and a unique first-pulse wake-up feature, all ICs are suitable for operation in self-biased power supplies. The ICs also have a dual-function pin for high-speed cycle-by-cycle current limiting or for selecting a low-current stand-by state. The authors give functional descriptions, block schematics with waveforms, and application examples.<<ETX>>

Power Management Solutions for Desktop and Mobile CPUS

This paper focuses on the power management solutions for desktop and mobile CPUs, with special emphasis on the control aspects and the related control IC requirements and architectures for VRM applications. The paper discusses the following topics: power converter topologies, load transient response, the ADOPTTM voltage positioning technology, maintaining high efficiency over a wide loadcurrent range, current and thermal balancing, current-sense solutions, protection functions, functional block schematics of VRM control ICs, and challenges for the IC designers.