Thomson Licensing

Didier Ploquin

Philippe Marchand

Gérard Morizot

Philippe Machand

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.

Display apparatus

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.

Sustain device for plasma panel

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.

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Parthenay de Bretagne, France

Didier Ploquin