UNIVERSAL DIMMING METHOD AND SYSTEM

• US 20100181935A1
• Filed: 07/01/2008
• Published: 07/22/2010
• Est. Priority Date: 07/25/2007
• Status: Active Grant

• Current Assignee: Philips Lighting BV (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Wu, Mingliang
• Granted Patent: US 8,324,827 B2
• Time in Patent Office: Days
• US Class Current: 315/307
• CPC Class Codes: H05B 41/3921 with possibility of light intensity variations

Abstract

A universal line voltage dimming method and system, with a control circuit for an electronic ballast operable to receive ballast input power and an outboard dedicated dimming signal including a power sensing circuit (27) generating a sensed power signal (52) in response to the ballast input power (20); an on-time converter (50) generating an on-time signal (54) in response to the sensed power signal (52); a dedicated dimming interface (122) operable to generate a dedicated dimming signal (124) in response to the outboard dedicated dimming signal (120); and a microprocessor (56) operable to generate a dimming control signal (58) in response to at least one of the on-time signal (54) and the dedicated dimming signal (120). The on-time signal (54) determines the dimming control signal (58) when mains power is phase cut power.

Claims

1. A control circuit for an electronic ballast operable to receive ballast input power and to receive an outboard dedicated dimming signal comprising:

a power sensing circuit 27, the power sensing circuit 27 generating a sensed power signal 52 in response to the ballast input power 20;

an on-time converter 50, the on-time converter 50 generating an on-time signal 54 in response to the sensed power signal 52;

a dedicated dimming interface 122, the dedicated dimming interface 122 being operable to generate a dedicated dimming signal 124 in response to the outboard dedicated dimming signal 120; and

a microprocessor 56, the microprocessor 56 being operable to generate a dimming control signal 58 in response to at least one of the on-time signal 54 and the dedicated dimming signal 120;

wherein the on-time signal 54 determines the dimming control signal 58 when mains power is phase cut power.

2. The circuit of claim 1 wherein the dedicated dimming signal 120 determines the dimming control signal 58 when mains power is not phase cut power.

3. The circuit of claim 1 wherein the dedicated dimming interface 122 is operable to receive the outboard dedicated dimming signal 120 from a dimmer selected from the group consisting of a 0-10V dimmer, a PWM dimmer, and a DALI dimmer.

4. The circuit of claim 1 further comprising a plurality of dedicated dimming interfaces 122 operable to generate a plurality of dedicated dimming signals 124 in response to a plurality of outboard dedicated dimming signals 120, the plurality of dedicated dimming signals 124 being received at the microprocessor 56.

5. The circuit of claim 1 further comprising:

a line voltage detector 60, the line voltage detector 60 generating a line voltage signal 62 in response to the sensed power signal 52; and

a capacitance circuit 66, the capacitance circuit 66 being responsive to a capacitance selector signal 64 to adjust capacitance of a boost/power factor controller 32;

wherein the microprocessor 56 is responsive to the line voltage signal 62 and generates the capacitance selector signal 64.

6. A lamp control method for an electronic ballast comprising:

sensing ballast input power;

determining whether the ballast input power is phase cut power 202;

implementing in-line dimmer control when the ballast input power is phase cut power 204;

determining whether a first dedicated dimmer is present when the ballast input power is not phase cut power 206; and

implementing first dedicated dimmer control when the first dedicated dimmer is present 208.

7. The method of claim 6 further comprising implementing in-line dimmer control when the first dedicated dimmer is not present.

8. The method of claim 6 further comprising:

determining whether a second dedicated dimmer is present when the first dedicated dimmer is not present 210; and

implementing second dedicated dimmer control when the second dedicated dimmer is present 212.

9. The method of claim 8 further comprising:

determining whether a third dedicated dimmer is present when the first dedicated dimmer is not present 214; and

implementing third dedicated dimmer control when the third dedicated dimmer is present 216.

10. The method of claim 6 wherein the determining whether the ballast input power is phase cut power 202 comprises determining whether the ballast input power has a phase parameter indicating that the ballast input power is phase cut power.

11. The method of claim 10 wherein the phase parameter is selected from the group consisting of phase angle and on-time.

12. The method of claim 6 wherein the determining whether the ballast input power is phase cut power 202 comprises determining whether voltage of the ballast input power is non-zero above a predetermined phase angle.

13. The method of claim 6 wherein the determining whether the ballast input power is phase cut power 202 comprises determining whether on-time of the ballast input power is less than a predetermined on-time.

14. The method of claim 6 further comprising:

determining line voltage for the sensed ballast input power; and

adjusting boost/power factor controller capacitance in response to the line voltage.

15. A lamp control system comprising:

means for sensing ballast input power;

means for determining whether the ballast input power is phase cut power;

means for implementing in-line dimmer control when the ballast input power is phase cut power;

means for determining whether a first dedicated dimmer is present when the ballast input power is not phase cut power; and

means for implementing first dedicated dimmer control when the first dedicated dimmer is present.

16. The system of claim 15 further comprising implementing in-line dimmer control when the first dedicated dimmer is not present.

17. The system of claim 15 further comprising:

means for determining whether a second dedicated dimmer is present when the first dedicated dimmer is not present; and

means for implementing second dedicated dimmer control when the second dedicated dimmer is present.

18. The system of claim 17 further comprising:

means for determining whether a third dedicated dimmer is present when the first dedicated dimmer is not present; and

means for implementing third dedicated dimmer control when the third dedicated dimmer is present.

19. The system of claim 15 wherein the means for determining whether the ballast input power is phase cut power comprises means for determining whether the ballast input power has a phase parameter indicating that the ballast input power is phase cut power.

20. The system of claim 19 wherein the phase parameter is selected from the group consisting of phase angle and on-time.

21. The system of claim 15 wherein the means for determining whether the ballast input power is phase cut power comprises means for determining whether voltage of the ballast input power is non-zero above a predetermined phase angle.

22. The system of claim 15 wherein the means for determining whether the ballast input power is phase cut power comprises means for determining whether on-time of the ballast input power is less than a predetermined on-time.

23. The system of claim 15 further comprising:

means for determining line voltage for the sensed ballast input power; and

means for adjusting boost/power factor controller capacitance in response to the line voltage.