US 10,334,669 B2
LED arrangement and LED driving method
Shan Wang, Shanghai (CN); Chun Yang, Shanghai (CN); Zhi Quan Chen, Shanghai (CN); Gang Wang, Shanghai (CN); and Jie Fu, Shanghai (CN)
Assigned to SIGNIFY HOLDING B.V., Eindhoven (NL)
Filed by SIGNIFY HOLDING B.V., Eindhoven (NL)
Filed on Mar. 15, 2018, as Appl. No. 15/922,039.
Claims priority of application No. PCT/CN2017/076827 (WO), filed on May 15, 2017; and application No. 17172295 (EP), filed on May 22, 2017.
Prior Publication US 2018/0352621 A1, Dec. 6, 2018
Int. Cl. H05B 33/08 (2006.01); H05B 37/02 (2006.01); H05B 39/04 (2006.01); G05F 1/10 (2006.01); F21Y 115/10 (2016.01)
CPC H05B 33/0815 (2013.01) [G05F 1/10 (2013.01); H05B 33/083 (2013.01); H05B 33/0812 (2013.01); H05B 33/0848 (2013.01); H05B 39/044 (2013.01); F21Y 2115/10 (2016.08); Y02B 20/343 (2013.01)] 15 Claims
OG exemplary drawing
 
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.