Abstract: A circuit for controlling illumination means in a display includes illumination means arranged in a series-connection that are supplied with an essentially constant current. For individually controlling the illumination means, switches are provided for bypassing individual illumination means, maintaining the essentially constant current in the series-connection. The switches are floating with respect to a ground potential. A coupling means is thus provided for proper control of the switches. In a development of the invention a floating local power supply is provided with each illumination means and switch for operating the switch. The local power supply is, in one embodiment, powered by the control signal that is used for controlling the bypass switch. In another embodiment provision is made for supplying power to the floating local power supply. A driving method according to the embodiments of the circuit is also described.

Abstract: The present invention concerns a device for generating a rectangular sustain voltage between the line scanning electrodes and the line common electrodes of luminous cells in a plasma panel. The device includes a first sustain amplifier connected to the line scanning electrode of the cells to produce the transitions of the first sustain voltage signal, and a second sustain amplifier connected to the line common electrode of the cells to produce the transitions of the second sustain voltage signal. It also includes an insulated voltage supply circuit which is connected directly to the line scanning electrodes and to the line common electrodes of the cells in order to hold the end-of-transition voltage on said line scanning electrodes and said line common electrodes.

Abstract: A circuit for controlling illumination means in a display includes illumination means arranged in a series-connection that are supplied with an essentially constant current. For individually controlling the illumination means, switches are provided for bypassing individual illumination means, maintaining the essentially constant current in the series-connection. The switches are floating with respect to a ground potential. A coupling means is thus provided for proper control of the switches. In a development of the invention a floating local power supply is provided with each illumination means and switch for operating the switch. The local power supply is, in one embodiment, powered by the control signal that is used for controlling the bypass switch. In another embodiment provision is made for supplying power to the floating local power supply. A driving method according to the embodiments of the circuit is also described.

Abstract: The present invention concerns a device for generating a rectangular sustain voltage between the line scanning electrodes and the line common electrodes of luminous cells in a plasma panel. The device includes a first sustain amplifier connected to the line scanning electrode of the cells to produce the transitions of the first sustain voltage signal, and a second sustain amplifier connected to the line common electrode of the cells to produce the transitions of the second sustain voltage signal. It also includes an insulated voltage supply circuit which is connected directly to the line scanning electrodes and to the line common electrodes of the cells in order to hold the end-of-transition voltage on said line scanning electrodes and said line common electrodes.

Abstract: The switched mode power supply comprises an inductor, a switching transistor coupled in series with the inductor, and a rectifier circuit. The rectifier circuit comprises a switch coupled with the inductor for a rectification of an output voltage and a control circuit operating in a monostable mode. The switch is operated in particular in a synchronous mode with the same switching frequency as the switching transistor. The rectifier circuit can be used advantageously with a switched mode power supply having a push-pull half-bridge configuration and operating as a resonant converter or a quasi-resonant converter with soft switching for an application within a plasma television set.

Abstract: In a display device images are reproduced by controlling the amount of light provided by a light source by means of light modulators for individual pixels. Subsequent images are synchronised to each other by synchronisation signals regularly occurring at intervals corresponding to first time periods. The backlight is controlled to emit light during fractions of second time periods or whole second time periods which are equal to or shorter than first time periods. Several of the second time periods may be nested and evenly distributed within the first time period. The signals for driving the backlight are preferably generated in synchronism with the horizontal pixel clock. Each of the fractions of second time periods or whole second time periods during which light is emitted is divided into a number of elementary steps, wherein each elementary step corresponds to a number of pixel clock periods.

Abstract: The present invention relates to a DC voltage converter with soft switching of the type with half-bridge arrangement at the primary side and of quasi-resonant half-wave type at the secondary side. This converter comprises a single transformer and can generate a plurality of regulated voltages at output. It furthermore comprises a resonant circuit for creating a half-wave resonant current in the secondary winding and charging a first load capacitor so as to produce a first DC voltage. It furthermore comprises an inductive circuit connected between said secondary winding and a second load capacitor able to generate a current so as to charge the second load capacitor during a part of the half-wave of the resonant current flowing in the secondary winding and thus produce a second DC voltage.

Abstract: The present invention relates to a DC voltage converter with soft switching of the type with half-bridge arrangement at the primary side and of quasi-resonant half-wave type at the secondary side. This converter comprises a single transformer and can generate a plurality of regulated voltages at output. It furthermore comprises a resonant circuit for creating a half-wave resonant current in the secondary winding and charging a first load capacitor so as to produce a first DC voltage. It furthermore comprises an inductive circuit connected between said secondary winding and a second load capacitor able to generate a current so as to charge the second load capacitor during a part of the half-wave of the resonant current flowing in the secondary winding and thus produce a second DC voltage.

Abstract: The present invention relates to a DC/DC converter of half-bridge type with soft switching comprising a transformer. The primary of the converter is of the type with half-bridge arrangement and is linked to an input voltage source by way of two switches and the secondary is of half-wave type and is linked to a load by means of an inductance. Means are provided for alternately controlling the two switches, at fixed frequency, by pulse width modulation. To reduce the number of components of the converter, a capacitor of small value is arranged in series with said primary winding, which capacitor referred back to the secondary is designed to resonate with said inductance. The inductance is the transformer's leakage inductance seen from the secondary. The switches are advantageously switched while the current in said inductance is not zero.

Abstract: The present invention relates to an amplifier designed to generate a rectangular voltage signal with soft switching on a capacitive load, comprising a half-bridge structure consisting of two switches, which is connected between a supply terminal and a reference terminal, the mid-point of said structure being connected to said capacitive load, and a soft-switching circuit with energy recovery. To limit the conduction losses in the amplifier, the soft-switching circuit with energy recovery comprises no active component, such as a diode or transistor. According to the invention, it is formed only from an inductive elements connected in series with a capacitive element between the terminals of said capacitive load. Advantageously, the inductive element comprises a saturable inductor in order to limit the conduction losses of the amplifier.

Abstract: The invention relates to a continuous voltage converter with soft switching, comprising a transformer (Np, Ns) whose primary is particularly of the type with a half-bridge mounting and is adapted to be connected to a source of input voltage (Ve) by means of two electronic switches (INT1, INT2) and whose secondary, of the mono-alternating type, is adapted to be connected to a load by means of an inductance in series (L2) and means (1 to 3, G1, G2) to control alternatingly the two switches, at fixed frequency, according to a regulation by modification of the pulse width as a function of the output voltage (Vo), so as to provide to said primary a switching at zero voltage, said converter being characterized in that said secondary comprises moreover a resonant circuit (L1, C1) so as to provide for said secondary a quasi-resonant switching at zero current.