SCR DIMMING CIRCUIT AND METHOD
First Claim
1. A silicon-controlled rectifier (SCR) dimming circuit, comprising:
- a) an SCR rectifying circuit having an SCR element configured to receive an AC power supply, and to generate a lack-phase AC voltage;
b) a rectifier bridge coupled to said SCR rectifying circuit, wherein said rectifier bridge is configured to convert said lack-phase AC voltage to a lack-phase DC voltage, wherein said lack-phase DC voltage is configured to be filtered through a filter capacitor to generate a smooth DC voltage;
c) a conduction phase angle signal generator coupled to said rectifier bridge, wherein said conduction phase angle signal generator is configured to receive said lack-phase DC voltage, and to generate a controlling signal that indicates a conduction phase angle range of said SCR element; and
d) a dimming signal generator coupled to said conduction phase angle signal generator and being configured to compare said controlling signal and a slope reference signal to output a dimming signal, said dimming signal generator having a dimming phase angle range from a predetermined start-up phase angle to a cut-off phase angle, wherein said cut-off phase angle is determined by said filter capacitor and said AC power supply,e) wherein said slope reference signal is configured to indicate an average value at each phase angle of said AC power supply in a half cycle having a first reference corresponding to said start-up phase angle and a second reference corresponding to said cut-off phase angle,f) wherein when said controlling signal is equal to said first reference, a light-emitting diode (LED) load is configured to be controlled by said dimming signal to operate in a maximum luminance,g) wherein when said controlling signal is equal to said second reference, said LED load is configured to be controlled by said dimming signal to operate in a minimum luminance, andh) wherein when said controlling signal is between said first reference and said second reference, said LED load is configured to be controlled by said dimming signal to change linearly between said maximum luminance and said minimum luminance.
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Accused Products
Abstract
The present invention relates to a silicon-controlled rectifier (SCR) dimming circuit and method for regulating the luminance of a light-emitting diode (LED) load. In one embodiment, an SCR dimming circuit can include: an SCR rectifying circuit having an SCR element that receives an AC power supply, and generates a lack-phase AC voltage; a rectifier bridge that converts the lack-phase AC voltage to a lack-phase DC voltage, where the lack-phase DC voltage is filtered through a filter capacitor to generate a smooth DC voltage; a conduction phase angle signal generator that receives the lack-phase DC voltage and generates a controlling signal indicating a conduction phase angle range of the SCR element; and a dimming signal generator that compares the controlling signal and a slope reference signal to output a dimming signal to control the luminance of the LED load.
68 Citations
10 Claims
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1. A silicon-controlled rectifier (SCR) dimming circuit, comprising:
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a) an SCR rectifying circuit having an SCR element configured to receive an AC power supply, and to generate a lack-phase AC voltage; b) a rectifier bridge coupled to said SCR rectifying circuit, wherein said rectifier bridge is configured to convert said lack-phase AC voltage to a lack-phase DC voltage, wherein said lack-phase DC voltage is configured to be filtered through a filter capacitor to generate a smooth DC voltage; c) a conduction phase angle signal generator coupled to said rectifier bridge, wherein said conduction phase angle signal generator is configured to receive said lack-phase DC voltage, and to generate a controlling signal that indicates a conduction phase angle range of said SCR element; and d) a dimming signal generator coupled to said conduction phase angle signal generator and being configured to compare said controlling signal and a slope reference signal to output a dimming signal, said dimming signal generator having a dimming phase angle range from a predetermined start-up phase angle to a cut-off phase angle, wherein said cut-off phase angle is determined by said filter capacitor and said AC power supply, e) wherein said slope reference signal is configured to indicate an average value at each phase angle of said AC power supply in a half cycle having a first reference corresponding to said start-up phase angle and a second reference corresponding to said cut-off phase angle, f) wherein when said controlling signal is equal to said first reference, a light-emitting diode (LED) load is configured to be controlled by said dimming signal to operate in a maximum luminance, g) wherein when said controlling signal is equal to said second reference, said LED load is configured to be controlled by said dimming signal to operate in a minimum luminance, and h) wherein when said controlling signal is between said first reference and said second reference, said LED load is configured to be controlled by said dimming signal to change linearly between said maximum luminance and said minimum luminance. - View Dependent Claims (2, 3, 4, 5, 6, 10)
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7. A silicon-controlled rectifier (SCR) dimming method for regulating luminance of a light-emitting diode (LED) load, the method comprising:
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a) converting an external AC power supply to a lack-phase AC voltage; b) rectifying said lack-phase AC voltage to generate a lack-phase DC voltage; c) converting said lack-phase DC voltage to a controlling signal that indicates a conduction phase angle range of an SCR element; d) comparing said controlling signal and a slope reference signal to generate a dimming signal; e) controlling, by said dimming signal, said LED load to operate in a maximum luminance when said controlling signal is equal to a first reference of said slope reference signal; f) controlling, by said dimming signal, said LED load to operate in a minimum luminance when said controlling signal is equal to a second reference of said slope reference signal; and g) controlling, by said dimming signal, said LED load to change linearly when said controlling signal is between said first reference and said second reference of said slope reference signal. - View Dependent Claims (8, 9)
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Specification