Lamp transformer for use with an electronic dimmer and method for use thereof for reducing acoustic noise
First Claim
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.
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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.
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Citations
20 Claims
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1. A method for reducing acoustic noise produced during use of a lamp dimmer, the method comprising:
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(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. - View Dependent Claims (2)
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3. A controller for reducing acoustic noise produced during use of a leading edge dimmer, the controller comprising:
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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. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12)
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.
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5. The controller according to claim 3, wherein the linear switch comprises a MOSFET.
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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.
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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.
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8. The controller according to claim 7, wherein the trailing edge controller comprises:
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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.
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9. The controller according to claim 8, wherein the switch is a bipolar junction transistor.
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10. The controller according to claim 6, wherein the switch capacitor control switch is a MOSFET.
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11. The controller according to claim 3, being integral with an electronic transformer.
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12. The controller according to claim 4, being integral with an electronic transformer.
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13. An electronic transformer including a controller for reducing acoustic noise produced during use of a leading edge dimmer, the controller comprising:
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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. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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.
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15. The transformer according to claim 13, wherein the linear switch comprises a MOSFET.
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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.
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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.
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18. The transformer according to claim 14, wherein the trailing edge controller comprises:
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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.
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19. The transformer according to claim 18, wherein the switch is a bipolar junction transistor.
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20. The transformer according to claim 16, wherein the switch capacitor control switch is a MOSFET.
Specification