US Patent No. 10,172,202

CIRCUIT ARRANGEMENT FOR CONTROLLING A LED UNIT AND METHOD OF OPERATING THE SAME


Patent No. 10,172,202
Issue Date January 01, 2019
Title Circuit Arrangement For Controlling A Led Unit And Method Of Operating The Same
Inventorship Dennis Johannes Antonius Claessens, Eindhoven (NL)
Jascha Van Pommeren, Utrecht (NL)
Jan Wojciech Obrebski, Eindhoven (NL)
Yi Wang, Delft (NL)
Philip Louis Zulma Vael, Temse (BE)
Sait Izmit, Utrecht (NL)
Assignee PHILIPS LIGHTING HOLDING B.V., Eindhoven (NL)

Claim of US Patent No. 10,172,202

1. A circuit arrangement for controlling the brightness of at least one LED unit, the circuit arrangement comprising:an input for receiving a phase-cut operating voltage having an amplitude from a power supply;
a signal processor, connected with said input and adapted to provide a dimming signal for said at least one LED unit from said phase-cut operating voltage, said signal processor being configured to operate at least in a noise suppression mode and a dimming mode; and
a control device, connected with said signal processor and configured to set the mode of said signal processor in dependence of the variation in said phase-cut operating voltage, and to determine said variation by comparing said amplitude of said phase-cut operating voltage with a reference signal to determine whether the amplitude of said phase-cut operating voltage exceeds a predetermined threshold value, wherein said control device comprises a switchable control circuit comprising a resistor in series with a diode arrangement of two parallel connected opposing diodes, to provide an alternative current path through the resistor so that a cut-off frequency of the signal processor is set to a second cut-off frequency;
wherein said reference signal corresponds to said dimming signal,
wherein the predetermined threshold value is at least as high as a forward voltage of one of the opposing diodes.