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Analysis, design, practical consideration, and implementation of a microprocessor-based toggle-control lighting system are presented. The system is primarily configured with a power factor corrector (PFC), a square-wave voltage generator, a manually controlled toggle switch, and two relays. Toggling the toggle switch can select a different number of lamps in operation, resulting in a mutual dimming feature. A lighting system with this specific ballast gains the merits of lower system cost and more flexibilities in lighting fixture design, as compared to conventional systems. Index Terms - Ballast, fluorescent lamp.

This paper presents the analysis, design, and practical consideration of a single-stage electronic dimming ballast with unity power factor. The power stage of the ballast is derived from combining a buck-boost converter and a half-bridge series-resonant parallel-loaded inverter (SRPLI). With the plasma model of the lamp, the analysis of the ballast is carried out, from which the key equations used for dimming control are derived. Starting performance and dimming consideration are also addressed in the paper. In this dimming ballast, both pulsewidth modulation (PWM) and variable-frequency control strategies are employed. The discussed ballast with the controls can save a controller and a switch driver, reduce size and cost, and possibly increase system reliability over conventional two-stage systems in the applications with moderate power level. Simulated and experimental results of the ballast for an OSRAM T8 32-W lamp are used to verify the discussion. Index Terms - Electronic ballast, power factor correction, single stage.

Analysis, design, and practical consideration of a single-stage electronic ballast with dimming feature and unity power factor are presented in this paper. The proposed single-stage ballast is the combination of a boost converter and a half-bridge series-resonant parallel-loaded inverter. The boost semistage working in the discontinuous conduction mode functions as a power factor corrector and the inverter semistage operated above resonance are employed to ballast the lamp. Replacing the lamp with the plasma model, analysis of the ballast is fulfilled. The dimming feature is carried out by pulse-width modulation (PWM) and variable-frequency controls simultaneously. The proposed single-stage ballast is suitable for applications with moderate power level and low-line voltage while requiring a high-output voltage. It can save a controller, an active switch and its driver, reduce size, and possibly increase system reliability while requiring two additional diodes over a conventional two-stage system. A prototype was implemented to verify the theoretical discussion. The hardware measurements have shown that the desired performance can be achieved feasibly. Index Terms - Electronic dimming ballast, plasma model, power factor corrector.

A unified approach to developing single-stage power converters which can fulfill multiple functions is presented. Four synchronous switches corresponding to the four common node types of two active switches are introduced. The approach is then to replace the active switches in multistage converters (in cascade or cascade connection) with one or several of the synchronous switches and their degenerated versions to form a single-stage converter. Illustrations of using these switches to develop single-stage converters are presented. These are started with the development of the well-known single-stage switch-mode converters (SMCs), buck-boost, Cuk, sepic, and Zeta (also named dual sepic), from the basic converters, buck and boost. Then, synthesis and applications of other single-stage converters are addressed. Due to increased component stresses, the developed single-stage converters are primarily suitable for applications with moderate power levels.

Off-line applications with single-stage converters (SSC's) are presented in the paper. The approach used in synthesizing the SSC's is first described, and their applications are then introduced. In addition, viable control strategies for the SSC's are addressed. The developed SSC's can fulfill multifunctions, such as input power factor correction, fast output regulation and lamp ballasting, and possess the merits of compact size, simple driver design and high reliability. Prototypes of SSC's applied to an electronic dimming ballast and a dc regulator are built, which show high feasibility in such moderate power applications. Index Terms - Electronic ballast, off-line application, single-stage converter, synchronous switch.

A simple, but accurate, PSpice circuit model simulating the electrical characteristics of low-pressure gaseous discharge lamp operating at high frequency is proposed. The model is constructed from a two-parameter equation and is suitable for computer simulation and analytic derivation in a preliminary design of electronic dimming ballasts. Simulated and measured results are used to verify the theoretical discussion. Index Terms - Electronic dimming ballasts, low-pressure gaseous discharge lamps, PSpice circuit model.

This paper presents the analysis and design of a series-resonant parallel-loaded inverter applied to electronic dimming ballasts with bifrequency and fuzzy logic control. The analysis of the ballast is carried out in conjunction with the fluorescent lamp represented in a plasma model. The component values of the power stage, as well as two switching frequencies, according to the desired maximum and minimum power levels are, therefore, determined. The power levels in between are controlled by varying the ratio between two time intervals for which the two frequencies last, respectively. This mechanism is achieved by using a fuzzy logic controller (FLC). A ballast prototype with the FLC which is implemented on an 8-bit microprocessor with a reduced instruction set computer architecture has been built. Experimental measurements have shown the feasibility of the ballast with the proposed control strategy. Index Terms--Ballast, fuzzy control.

An alternative approach to synthesizing single-stage converters (SSC's) with power-factor-correction (PFC) feature is presented in this paper. The proposed approach is primarily based on the concept of dither effect, from which PFC cells composed of energy buffers and high-frequency dither signals are introduced. Properly selecting an eligible PFC cell and inserting it in between input rectifier and dc-link capacitor can yield an SSC which can improve the input power factor significantly. In this paper, principle and configuration of PFC cells are addressed; thus, quite a few families of SSC's can be synthesized from the derived PFC cells. With this approach, not only can the SSC's discussed in the literature be developed alternatively, but novel SSC's can be synthesized. Most of the SSC's have been proved in the literature to be feasible in applications with moderate power levels. Index Terms - Power-factor correction, power-factor-correction cell, single-stage converter.