Interface circuit for a light source

Patent metadata

Field	Value
Publication number	US-9301354-B2
Application number	US-201214008580-A
Country	US
Kind code	B2
Filing date	Mar 27, 2012
Priority date	Mar 30, 2011
Publication date	Mar 29, 2016
Grant date	Mar 29, 2016

Abstract

An interface circuit is disclosed for operating a light source from an electronic fluorescent driver. In one example, the interface circuit comprises
input terminals for connection to lamp connection terminals of the electronic fluorescent lamp driver, a first string interconnecting a first pair of input terminals, a second string interconnecting a second pair of input terminals, a third string interconnecting a first terminal of the first string and a second terminal of the second string and comprising a rectifier, output terminals of said rectifier being coupled during operation to the light source.

When a light source is operated making use of the interface circuit, a proper emulation of a fluorescent lamp is obtained.

First claim

The invention claimed is:

1. An interface circuit for operating a light source, equipped with
input terminals for connection to lamp connection terminals of an electronic fluorescent lamp driver,
a first string, conductively interconnecting a first pair of input terminals,
a second string, conductively interconnecting a second pair of input terminals,
a third string, conductively interconnecting a first terminal of the first string and a second terminal of the second string, wherein
the third string comprises a rectifier, output terminals of said rectifier being coupled, during operation, to the light source, and a first switching element for controlling the conductive state of the third string, such that the third string delivers a driving current to the light source when the first switching element is conductive,
a fourth string coupled to the third string and comprising a sensor circuit, having an output terminal coupled to a control electrode of the first switching element, for sensing the amplitude of a high frequency AC voltage between the first and the second terminal and for rendering the first switching element conductive when the amplitude of the high frequency AC voltage reaches a predetermined value.

2. The interface circuit as claimed in claim 1 , wherein the light source is a high pressure discharge lamp.

3. The interface circuit as claimed in claim 1 , wherein the light source is a LED-array.

4. The interface circuit as claimed in claim 1 , wherein the light source comprises an OLED.

5. The interface circuit as claimed in claim 1 , wherein the interface circuit comprises a DC-DC-converter coupled, during operation, between output terminals of the rectifier and the light source.

6. The interface circuit as claimed in claim 1 , wherein the interface circuit comprises a capacitor that, during operation, shunts the light source.

7. The interface circuit as claimed in claim 6 , wherein the interface circuit is equipped with a fifth string connected in parallel to the third string and comprising an impedance and a further switching element having its control electrode coupled to an output terminal of the sensor circuit.

8. The interface circuit as claimed in claim 6 , wherein the interface circuit is equipped with a fifth string coupled between output terminals of the rectifier comprised in the third string and comprising an impedance and a further switching element, wherein a control electrode of the further switching element is coupled to an output terminal of the sensor circuit.

9. The interface circuit as claimed in claim 6 , wherein the interface circuit is equipped with a fifth string coupled between input terminals of the rectifier comprised in the third string and comprising an impedance.

10. The interface circuit as claimed in claim 8 , wherein the impedance is a resistor.

11. The interface circuit as claimed in claim 8 , wherein the impedance is a capacitor.

12. A method of operating a light source, making use of an electronic fluorescent lamp driver, comprising the steps of
providing a first string coupled between a first pair of lamp connection terminals of the electronic fluorescent lamp driver,
providing a second string coupled between a second pair of lamp connection terminals of the fluorescent lamp driver,
providing a rectifier,
providing a third string coupled between a first terminal of the first string and a second terminal of the second string,
Including,
coupling the output terminals of said rectifier in the third string, during operation, to the light source, and a first switching element controlling the conductive state of the third string, such that the third string delivers a driving current to the light source when the first switching element is conductive,
providing a fourth string coupled to the third string for sensing a high frequency AC voltage between the first and the second string and rendering the first switching element conductive when the amplitude of the high frequency AC voltage reaches a predetermined value.

13. The method according to claim 12 , further comprising the steps of
providing a fifth string connected in parallel to the third string and comprising an impedance and a further switching element having its control electrode coupled to an output terminal of the sensor circuit, and
rendering the further switching element conductive when the sensed amplitude of the high frequency AC voltage reaches the predetermined value.

14. The method according to claim 12 , wherein the light source is one of the group formed by LED, OLED and high pressure discharge lamp.

15. An interface circuit for operating a light source, equipped with
input terminals for connection to lamp connection terminals of an electronic fluorescent lamp driver,
a first string, conductively interconnecting a first pair of input terminals,
a second string, conductively interconnecting a second pair of input terminals,
a third string, conductively interconnecting a first terminal of the first string and a second terminal of the second string, wherein the third string comprises a rectifier, output terminals of said rectifier being coupled, during operation, to the light source, and a first switching element for controlling the conductive state of the third string,
a fourth string coupled to the third string and comprising a sensor circuit, having an output terminal coupled to a control electrode of the first switching element, for sensing the amplitude of a high frequency AC voltage between the first and the second terminal and for rendering the first switching element conductive when the amplitude of the high frequency AC voltage reaches a predetermined value,
a capacitor that, during operation, shunts the light source, and
a fifth string connected in parallel to the third string and comprising an impedance and a further switching element having its control electrode coupled to an output terminal of the sensor circuit.

Assignees

• Loef Christoph
• Tao Haimin
• Koninkl Philips Nv

Inventors

• Loef Christoph
• Tao Haimin

Classifications

• H05B45/60

  Circuit arrangements for operating LEDs comprising organic material, e.g. for operating organic light-emitting diodes [OLED] or polymer light-emitting diodes [PLED] · CPC title

• H05B45/37 Primary

  Converter circuits · CPC title

• H05B33/0824

  Electricity · mapped topic

• H05B33/0809

  Electricity · mapped topic

• H05B33/0896

  Electricity · mapped topic