US Patent No. 10,334,669

LED ARRANGEMENT AND LED DRIVING METHOD


Patent No. 10,334,669
Issue Date June 25, 2019
Title Led Arrangement And Led Driving Method
Inventorship Shan Wang, Shanghai (CN)
Chun Yang, Shanghai (CN)
Zhi Quan Chen, Shanghai (CN)
Gang Wang, Shanghai (CN)
Jie Fu, Shanghai (CN)
Assignee SIGNIFY HOLDING B.V., Eindhoven (NL)

Claim of US Patent No. 10,334,669

1. A lighting circuit comprising:an input adapted to receive a time-variable input voltage;
a first plurality of LEDs having a first forward voltage;
a second plurality of LEDs having a second forward voltage, the second forward voltage being at least double the first forward voltage;
a plurality of LED segments comprising at least a first LED segment and a last LED segment, wherein the first LED segment comprises more LEDs of the first plurality of LEDs than the second plurality of LEDs, wherein the last LED segment comprises more LEDs of the second plurality of LEDs than the first plurality of LEDs;
a switch network coupled to the plurality of LED segments,
wherein the switch network, including a plurality of switches elements respectively coupled to the plurality of LED segments, is adapted to:
switch only the first LED segment when an amplitude of the time-variable input voltage is below a first threshold, and
switch the first LED segment and the last LED segment in series when the amplitude of the time-variable input voltage is above a last threshold, such that a total forward voltage of the plurality of LED segments is selected in dependence on the amplitude of the time-variable input voltage.