Efficient lighting circuit for led assemblies

Patent metadata

Field	Value
Publication number	US-2016353535-A1
Application number	US-201615161328-A
Country	US
Kind code	A1
Filing date	May 23, 2016
Priority date	May 28, 2015
Publication date	Dec 1, 2016
Grant date	—

Abstract

A lighting circuit and a method of operating a lighting circuit are described. A rectifier 14 has an input for an alternating voltage V. At least a first and a second LED assembly 20, 22 are connected to be supplied with electrical power from the rectifier 14 . The first LED assembly 20 is electrically connected to a first output 26 of the rectifier 14 and electrically connected in series with an input 36 of a switching converter circuit. The second LED assembly 22 is electrically connected to an output 48 of the switching converter circuit 44 . A control assembly 30 is connected to a tap 46 in the series connection for controlling operation of the first LED assembly 20.

First claim

1 . Lighting circuit, including
a rectifier with an input for an alternating voltage, and at least a first and a second LED assembly connected to be supplied with electrical power from said rectifier, wherein said first LED assembly is electrically connected in series with a first output of said rectifier, said first LED assembly being further electrically connected in series with an input of a switching converter circuit, and said second LED assembly is electrically connected to an output of said switching converter circuit, and wherein a control assembly for controlling operation of said first LED assembly is connected to a tap in said series connection.

2 . Lighting circuit according to claim 1 , wherein
said control assembly comprises a switching element controllable at least in a conducting and non-conducting state, said switching element being connected to bypass said first LED assembly in said conducting state.

3 . Lighting circuit according to claim 1 , wherein
said control assembly comprises a controllable current source connected between said tap and a return path to a second output of said rectifier.

4 . Lighting circuit according to claim 1 , wherein
said switching converter circuit comprises at least a reactive element, a controllable switching element and a control circuit for controlling said controllable switching element to repeatedly alternate between a conducting and a non-conducting state.

5 . Lighting circuit according to claim 1 , wherein
at least a third LED assembly is electrically connected in said series connection between said first output of said rectifier and said input of said switching converter, and wherein a control assembly for controlling operation of said third LED assembly is connected to a tap in said series connection.

6 . Lighting circuit according to claim 1 , wherein
said switching converter circuit comprises at least two input terminals, wherein a capacitor is connected between said two input terminals.

7 . Lighting circuit according to claim 6 , wherein
said capacitor is electrically connected in series at least to said first LED assembly.

8 . Lighting circuit according to claim 1 , wherein
at least one of said LED assemblies comprises multiple LED elements electrically connected in series, in parallel, or in a series/parallel connection.

9 . Lighting circuit according to claim 1 , wherein
a stabilizing capacitor is electrically connected in parallel with at least one of said LED assemblies.

10 . Lighting circuit according to claim 1 , wherein
said second LED assembly is electrically connected in series with said first LED assembly.

11 . Lighting circuit according to claim 1 , wherein
said second LED assembly is electrically connected between said first LED assembly and an input of said switching converter circuit.

12 . Lighting circuit according to claim 1 , wherein
a current source is electrically connected in series to said first LED assembly.

13 . Method of operating a lighting circuit, comprising
supplying a rectifier with an alternating voltage to supply electrical power from said rectifier to at least a first and a second LED assembly, wherein said first LED assembly is electrically connected in series with a first output of said rectifier, said first LED assembly being electrically connected in series with an input of a switching converter circuit, and wherein said second LED assembly is electrically connected to an output of said switching converter circuit, and wherein a control assembly for controlling operation of said first LED assembly is connected to a tap in said series connection.

Assignees

• Philips Lighting Holding Bv

Inventors

• Arulandu Kumar
• Linnartz Johan-Paul Marie Gerard
• De Mol Eugen Jacob
• Malyna Dmytro Viktorovych
• Kahlman Henricus Marius Joseph Maria

Classifications

• H05B45/37

  Converter circuits · CPC title

• H05B45/48 Primary

  having LEDs organised in strings and incorporating parallel shunting devices · CPC title

• H05B33/0815 Primary

  Electricity · mapped topic

• H05B44/00

  Circuit arrangements for operating electroluminescent light sources (for operating light emitting diodes H05B45/00) · CPC title

• H05B45/375

  using buck topology · CPC title