Abstract: The invention provides an apparatus and a method for controlling the power output of a fluorescent lamp in order to provide dimming control. The fluorescent lamp is driven by an electronic ballast, for example a half-bridge resonant inverter, and the electronic ballast is switched at a constant frequency and with a constant duty-cycle, but with a variable DC voltage power input. Dimming control is provided by variation of the DC voltage power supply. The variable DC supply may be obtained from an AC source followed by a power factor corrected AC-DC variable converter, or a DC source followed by a variable DC—DC converter.

Abstract: The present invention provides an apparatus and method for determining the characteristic(s) of a discharge lamp (f rto example a fluorescent lamp or a high-intensity discharge lamp) operated by a high-frequency electronic ballast including a resonant tank comprising an inductor and a capacitor, wherein said characteristic(s) are selected from the group consisting of lamp input voltage, lamp resistance and lamp power, comprising means for measuring the inductor voltage and/or current, and means for determining said characteristic(s) from the measured inductor voltage and/or current. More generally, the present invention provides techniques for determining a number of parameters of a power converter circuit simply from easuring an inductir voltage or inductor current.

Abstract: The invention provides an apparatus and a method for controlling the power output of a fluorescent lamp in order to provide dimming control. The fluorescent lamp is driven by an electronic ballast, for example a half-bridge resonant inverter, and the electronic ballast is switched at a constant frequency and with a constant duty-cycle, but with a variable DC voltage power input. Dimming control is provided by variation of the DC voltage power supply. The variable DC supply may be obtained from an AC source followed by a power factor corrected AC-DC variable converter, or a DC source followed by a variable DC-DC converter.

Abstract: A bidirectional switched-capacitor power converter has a first step-up mode and a second step-down mode. The converter includes a capacitor in which in both modes is charged during a first switch topology and then discharged during a second switch topology. Two converters operating out of phase may be disposed in parallel to enable continuous power conversion.