Multichannel lighting unit and driver for supplying current to light sources in multichannel lighting unit

Patent metadata

Field	Value
Publication number	US-9345079-B2
Application number	US-201314105615-A
Country	US
Kind code	B2
Filing date	Dec 13, 2013
Priority date	Aug 25, 2009
Publication date	May 17, 2016
Grant date	May 17, 2016

Abstract

A lighting unit includes at least two channels of light sources, and a driver for the light sources. The driver includes a DC/DC converter and a control arrangement for controlling the current supplied to at least one of the two channels in response to a control signal produced by the DC/DC converter. Beneficially, a feedback loop controls a switching device in the DC/DC converter to maintain the light level produced by the light sources at a desired level regardless of changes in the supply voltage arid the load.

First claim

The invention claimed is:

1. An apparatus, comprising:
a first channel of first light emitting devices (LEDs);
a second channel of second LEDs , at least one of the second LEDs having at least one of a different color and a different color temperature than at least one of the first LEDs; and

a driver for driving the first and second channels of LEDs, the driver including:
a first stage converter configured to receive a first DC voltage and to output a second DC voltage,
a second stage converter configured to receive the second DC voltage and to generate an output voltage that causes a first current to flow through the first channel of LEDs and a second current to flow through the second channel of LEDs,
a current control device configured to control the second current flowing through to the second channel of LEDs in response to a control signal, and
a feedback device configured to sample at least one of the first current and the second current and in response thereto to control a switching operation of the second stage converter.

2. The apparatus of claim 1 , wherein the first stage converter comprises a flyback converter, the second stage converter comprises a buck converter, and the current control device comprises a pulse width modulator.

3. The apparatus of claim 2 , wherein the control signal for controlling the second current flowing through the second channel of LEDs is produced from an inductor winding in one of the flyback converter and the buck converter.

4. The apparatus of claim 2 , wherein the inductor winding from which the control signal is generated is a primary winding of a transformer in the flyback converter.

5. The apparatus of claim 2 , wherein the inductor winding from which the control signal is generated is a secondary winding of a transformer in the flyback converter.

6. The apparatus of claim 2 , wherein the inductor winding from which the control signal is generated is an inductor winding of the buck converter.

7. The apparatus of claim 1 , wherein at least one of the first LEDs emits a white light, and wherein at least one of the second LEDs emits a non-white colored light.

8. The apparatus of claim 1 , wherein the first channel of first LEDs is connected in series with the second channel of second LEDs.

9. The apparatus of claim 1 , wherein the first channel of first LEDS are connected in series with each other and the second channel of second LEDs are connected in search with each other.

10. The apparatus of claim 1 , further comprising a temperature sensor configured to sense a temperature of at least one of the first and second LEDs, and in response thereto to generate a feedback signal for adjusting the output voltage.

11. The apparatus of claim 1 , further comprising a light sensor configured to sense light produced by the first and second LEDs, and, in response thereto, to generate a feedback signal for adjusting the output voltage.

12. An apparatus, comprising:
a plurality of light sources comprising first to Nth channels, each channel having at least one of a different color and a different color temperature than all of the light sources in each of the other channels;
a driver for driving the plurality of light sources, the driver including:
a DC/DC converter configured to receive a DC voltage and to output a desired voltage level for driving the first to the N channels of light sources;
a control device configured to receive a current control signal derived from the output of the DC/DC converter and in response control current through one or more of the first through Nth channels of light sources.

13. The apparatus of claim 12 , wherein the plurality of light sources comprises a first group of light sources connected in series with each other arid a second group of light sources connected in series with each other, at least one of the light sources of the second group having at least one of a different color and a different color temperature than at least one of the light sources of the first group.

14. The apparatus of claim 13 , wherein the control device configured to control the second current flowing through to the second group of light sources in response to a control signal, wherein the control signal for controlling the second current flowing through the second group of light sources is produced by the DC/DC converter.

15. The apparatus of claim 12 , wherein the control device comprises a pulse width modulator that controls the second current flowing through the second group of light sources by shunting the second current across one or more of the second light sources in response to the control signal.

16. The apparatus of claim 12 , wherein the DC/DC converter includes a flyback converter, and wherein the control signal for controlling the second current flowing through the second group of light sources is produced by a winding of a transformer in the flyback converter.

17. The apparatus of claim 12 , wherein the second group of light sources have one of a different color and a different color temperature than the first group of light sources.

18. The apparatus of claim 12 , wherein the DC/DC converter includes a buck converter, and wherein the control signal for controlling the second current flowing through the second group of light sources is produced by an inductor winding in the buck converter.

19. The apparatus of claim 12 , wherein the driver further comprises a feedback device configured to sample at least one of the first current and the second current and in response thereto to control a switching operation of the DC/DC converter.

20. The apparatus of claim 12 , wherein the driver further comprises a sensor configured to sense one of a temperature and light emitted by at least one of the first and second light sources, and in response thereto to generate a feedback signal for adjusting the output voltage of the DC/DC converter.

Assignees

• Koninkl Philips Nv

Inventors

• Moss Timothy B

Classifications

• H05B45/10

  Controlling the intensity of the light · CPC title

• H05B45/20 Primary

  Controlling the colour of the light · CPC title

• H05B45/37

  Converter circuits · CPC title

• H05B33/0851

  Electricity · mapped topic

• H05B33/0815 Primary

  Electricity · mapped topic