Easii Ic

Aledia

David Gras

Olivier Valorge

Frédéric Mercier

Nicolas Joubert

Thomas Peysson

An optoelectronic circuit for receiving a variable voltage containing alternating increasing and decreasing phases. The optoelectronic circuit includes assemblies of light-emitting diodes mounted in series; a current source connected to each assembly by a switch; for each switch, a first comparison module for comparing the current passing through the switch with a current threshold; a second comparison module for comparing a voltage representing the voltage at the terminals of the current source with a voltage threshold; and a control module connected to the first and second comparison modules and designed to control the opening and closing of the switches, during each increasing phase and each decreasing phase, according to signals supplied by the first and second comparison modules.

Optoelectronic circuit with light-emitting diodes

The invention relates to an optoelectronic circuit intended to receive, between a first node and a second node, a variable voltage, the optoelectronic circuit including: a plurality of light-emitting diodes series-assembled between the first node and a third node; a first current limitation/regulation circuit assembled between the third node and the second node; a switching circuit coupling the third node to at least certain light-emitting diodes of the plurality of light-emitting diodes; a capacitor including first and second plates; a first diode having its cathode connected to the second plate and having its anode coupled to the second node; and a second diode having its anode connected to the second plate and having its cathode coupled to the third node or to a second current limitation/regulation circuit.

Optoelectronic circuit comprising light-emitting diodes

An optoelectronic circuit intended to receive a variable voltage containing an alternation of rising and falling phases. The optoelectronic circuit includes assemblies of series-assembled light-emitting diodes, a node coupled to each assembly by a conduction circuit having its electric conductance varying according to a control signal and a control circuit coupled to each conduction circuit and capable of supplying each control signal based on the comparison of a first voltage at said node with at least a second voltage. The control circuit includes a difference amplifier and as many output stages as there are conduction circuits, the control circuit being capable of controlling the first voltage with the second voltage offset by a third voltage, different for each output stage.

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Echirolles, France

David Gras