Osram Gmbh

Osram S.p.a. - Societa' Riunite Osram Edison Clerici

Enrico Raniero

Paolo De Anna

Francesco Angelin

Felix Franck

Valerio Michielan

Daniele Luccato

A current sensing circuit for sensing an intermittent current having a Zero Current Period includes: an amperometric transformer having a primary winding for the current to be sensed to flow therethrough and a secondary winding, a sensing resistor coupled to the secondary winding of the transformer, an offset capacitor coupled with sensing resistor between the sensing resistor and ground, and a switch element acting across the coupling of the sensing resistor and the offset capacitor, the switch element being electrically conductive during the zero current period or a fraction thereof.

Current sensing circuit and corresponding method

An electronic converter comprising an input comprising two terminals for receiving a first power signal, and an output comprising two terminals for providing a second power signal. On the primary side, the converter comprises a half-bridge, a transformer and a first capacitor. Specifically, the first capacitor and the primary winding of the transformer are connected in series between the intermediate point of the half-bridge and an input terminal. On the secondary side, the converter comprises a diode, a second capacitor and an inductor. The second capacitor and the secondary winding of the transformer are connected in series between the cathode and anode of the diode, and the inductor and the output are connected in series between the cathode and the anode of the diode. The electronic converter comprises a third capacitor and at least one electronic switch adapted to selectively connect the third capacitor in parallel with the second capacitor.

Electronic converter and related method of operating an electronic converter

A lighting system includes an electronic converter, a lighting module and a switching stage. The electronic converter includes a transformer, a rectifier circuit and an output filter circuit. A capacitance is connected between the primary winding and the secondary winding. The lighting module includes a chain of LEDs and a current regulator, wherein the chain of LEDs is mounted onto a substrate of a metallic material, so that a parasitic capacitance is present between the lighting module and the substrate of a metallic material. The switching stage includes a field-effect transistor interposed in the negative line which connects the lighting module to the electronic converter, and a control unit configured to drive the gate terminal of the transistor as a function of a dimming signal. The switching stage includes a diode connected to negative output terminal of the switching stage and to positive output terminal of the switching stage.

Lighting system, related electronic converter and method of designing a lighting system

The lighting system includes a voltage source for generating a constant direct current adapted to supply lighting modules, a number n of electronic switches, a current sensor connected in series with the voltage source to detect a measurement signal indicative of the current provided by the voltage source, and a control unit. The control unit generates the drive signals for the electronic switches. It varies the drive signals, such that: in a first instant, all lighting modules are connected to the voltage source; and during a sequence of instants, each time a different set of lighting modules is connected to the voltage source. It then determines the current flowing through all lighting modules as a function of the measurement signal detected in the first instant, and determines the currents which flow through the various lighting modules as a function of the measurement signals detected during the sequence of instants.

Lighting system and related method of operating a lighting system

An arrangement for driving a light source, including a plurality of LED strings by means of a current generator, wherein each said LED string forms a respective current mesh with said current generator, includes: at least one inductor acting on said current meshes, in each of said current meshes, an electronic switch having a first, working node towards the LED string and a second, reference node opposed to the LED string. All the reference nodes of all the electronic switches are connected together, and the working node of each electronic switch is connected to the work node of at least another one of the electronic switches via at least one current averaging capacitor. The electronic switches can be selectively rendered conductive, each one at a respective time interval, thereby selectively distributing the current of the current generator over the LED strings.

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Codiverno di Vigonza, Italy

Enrico Raniero