Stmicroelectronics S.r.l.

Simone Crespi

Davide Lena

LED strings cascaded to one another are driven by an electronic circuit that includes regulation modules and a brightness-compensation module. The regulation modules carry out in sequence a current-regulation phase, in which they regulate the current that flows in the corresponding LED strings. The regulation module includes: a compensation regulator coupled to a compensation LED string and to a capacitor and a generator that generates an electrical quantity indicating the luminous flux emitted by the LED strings and by the compensation LED string. The compensation regulator regulates a current that flows in the compensation LED string as a function of the electrical quantity, discharging the capacitor through the compensation LED string.

Electronic circuit for driving LED strings so as to reduce the light flicker

An electronic circuit drives a plurality of LED strings connected in series. The electronic circuit includes a regulation module corresponding to each LED string, with the regulation module connected to the cathode terminal of the corresponding LED string. Each regulation module is further coupled to receive a reference voltage in phase with a rectified a.c. voltage. The regulation modules execute in turn and in sequence a current-regulation phase as a function of a trend of the reference voltage. Each regulation module, when executing the current-regulation phase, functions to regulate the current that flows in the corresponding LED string and in any previous LED strings in the series connection so that the regulated current is proportional to the reference voltage.

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San Vero Milis, Italy

Simone Crespi