Lamp transformer for use with an electronic dimmer and method for use thereof for reducing acoustic noise

• US 20030127994A1
• Filed: 10/23/2002
• Published: 07/10/2003
• Est. Priority Date: 01/10/2002
• Status: Active Grant

• Current Assignee: Savant Technologies, LLC (Savant Systems, LLC)
• Original Assignee: Lightech Electronic Industries Ltd. (Savant Systems, LLC)
• Inventors: Patchornik, Joshua, Barak, Shaul
• Granted Patent: US 6,713,974 B2
• Time in Patent Office: Days
• US Class Current: 315/291
• CPC Class Codes: H02M 1/44 Circuits or arrangements for compensating for electromagnetic interference in converters or inverters
• CPC Class Codes: H02M 5/293 using semiconductor devices only
• CPC Class Codes: H05B 39/048 with reverse phase control
• CPC Class Codes: H05B 39/08 by shifting phase of trigger voltage applied to gas-filled controlling tubes also in controlled semiconductor devices in converters H02M5/00; with regulation G05F1/44
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

A controller for reducing acoustic noise produced during use of a leading edge dimmer, includes a leading edge controller responsive to an input voltage fed thereto for producing a control signal upon detection of a leading edge, and a linear switch coupled to the leading edge controller and responsive to the control signal for linearly switching the input voltage so that a rate of rise of the leading edge is decreased. A trailing-edge controller may be coupled to a leading-trailing edge detector and responsive to detection of a trailing edge dimmer for disabling the leading edge controller and decreasing a rate of decline of the trailing edge of the input voltage.

Claims

1. A method for reducing acoustic noise produced during use of a lamp dimmer, the method comprising:

(a) detecting that a dimmer is present, and if so;

i) detecting whether the dimmer is a leading edge dimmer or a trailing edge dimmer,

ii) if the dimmer is a leading edge dimmer, reducing the rate of rise of the leading edge, and

iii) if the dimmer is a trailing edge dimmer, reducing the rate of fall of the trailing edge.

2. The method according to claim 1 being carried out within an electronic transformer coupled to a lamp for reducing acoustic noise produced by a dimmer when present.

3. A controller for reducing acoustic noise produced during use of a leading edge dimmer, the controller comprising:

a leading edge controller responsive to an input voltage fed thereto for producing a control signal upon detection of a leading edge, and

a linear switch coupled to the leading edge controller and responsive to the control signal for linearly switching the input voltage so that a rate of rise of the leading edge is decreased.

4. The controller according to claim 3 being further adapted for reducing acoustic noise produced during use of a trailing edge dimmer, and further comprising:

a leading-trailing edge detector responsive to an input voltage fed thereto for detecting whether the input voltage results from a leading edge dimmer or a trailing edge dimmer, and

a trailing edge controller coupled to the leading-trailing edge detector and responsive to detection of a trailing edge dimmer for disabling the leading edge controller and decreasing a rate of decline of the trailing edge of the input voltage;

said leading edge controller being coupled to the leading-trailing edge detector and responsive to detection of a leading edge dimmer for disabling the trailing edge controller.

5. The controller according to claim 3, wherein the linear switch comprises a MOSFET.

6. The controller according to claim 3, wherein the trailing edge controller comprises a switch capacitor control switch for coupling a switch capacitor to an output of the controller.

7. The controller according to claim 6, wherein the leading-trailing edge detector includes a trailing edge detector comprising a resistor, rectifier diode and capacitor whose voltage is proportional to the negative slope of the trailing edge.

8. The controller according to claim 7, wherein the trailing edge controller comprises:

a DC voltage source for charging a capacitor coupled to the switch capacitor control switch, and

a switch connected across the capacitor;

whereby when the voltage of the trailing edge is sufficiently negative, the switch is open circuit and the voltage across the capacitor causes the switch capacitor control switch to conduct.

9. The controller according to claim 8, wherein the switch is a bipolar junction transistor.

10. The controller according to claim 6, wherein the switch capacitor control switch is a MOSFET.

11. The controller according to claim 3, being integral with an electronic transformer.

12. The controller according to claim 4, being integral with an electronic transformer.

13. An electronic transformer including a controller for reducing acoustic noise produced during use of a leading edge dimmer, the controller comprising:

a leading edge controller responsive to an input voltage fed thereto for producing a control signal upon detection of a leading edge, and

a linear switch coupled to the leading edge controller and responsive to the control signal for linearly switching the input voltage so that a rate of rise of the leading edge is decreased.

14. The electronic transformer according to claim 13, wherein the controller is further adapted for reducing acoustic noise produced during use of a trailing edge dimmer, and comprises:

a leading-trailing edge detector responsive to an input voltage fed thereto for detecting whether the input voltage results from a leading edge dimmer or a trailing edge dimmer, and

a trailing edge controller coupled to the leading-trailing edge detector and responsive to detection of a trailing edge dimmer for disabling the leading edge controller and decreasing a rate of decline of the trailing edge of the input voltage;

said leading edge controller being coupled to the leading-trailing edge detector and responsive to detection of a leading edge dimmer for disabling the trailing edge controller.

15. The transformer according to claim 13, wherein the linear switch comprises a MOSFET.

16. The transformer according to claim 14, wherein the trailing edge controller comprises a switch capacitor control switch for coupling a switch capacitor to an output of the controller.

17. The transformer according to claim 14, wherein the leading-trailing edge detector includes a trailing edge detector comprising a resistor, rectifier diode and capacitor whose voltage is proportional to the negative slope of the trailing edge.

18. The transformer according to claim 14, wherein the trailing edge controller comprises:

a DC voltage source for charging a capacitor coupled to the switch capacitor control switch, and

a switch connected across the capacitor;

whereby when the voltage of the trailing edge is sufficiently negative, the switch is open circuit and the voltage across the capacitor causes the switch capacitor control switch to conduct.

19. The transformer according to claim 18, wherein the switch is a bipolar junction transistor.

20. The transformer according to claim 16, wherein the switch capacitor control switch is a MOSFET.