AC LED DIMMER AND DIMMING METHOD THEREBY
First Claim
1. An alternating current (AC) light-emitting diode (LED) dimmer, comprising:
- a rectifier to receive AC voltage from an AC voltage source and to first full-wave rectify the AC voltage;
a voltage converter to receive the first full-wave rectified voltage from the rectifier, to generate a second full-wave rectified stepped-up voltage, and to generate a pulse enable signal;
a pulse width modulation controller to receive the second full-wave rectified stepped-up voltage and to generate a pulse width modulation signal to dim an AC LED in response to the pulse enable signal; and
a switch to drive the AC LED under control of the pulse width modulation signal.
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Abstract
The disclosure relates to an AC LED dimmer and dimming method thereof. The AC LED dimmer includes a rectifier receiving AC voltage from an AC voltage source and full-wave rectifying the AC voltage; a direct current (DC)/DC converter receiving the full-wave rectified voltage from the rectifier, generating a full-wave rectified stepped-up voltage, and generating a pulse enable signal; a pulse width modulation controller receiving the full-wave rectified stepped-up voltage and generating a pulse width modulation signal to dim an AC LED in response to the pulse enable signal; a switch driving the AC LED under control of the pulse width modulation signal, and an electromagnetic interference (EMI) filter to be connected between the AC voltage source and the switch to eliminate electromagnetic interference from the AC voltage source. Accordingly, the dimmer can perform an efficient and linear dimming function and suppress harmonics.
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Citations
17 Claims
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1. An alternating current (AC) light-emitting diode (LED) dimmer, comprising:
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a rectifier to receive AC voltage from an AC voltage source and to first full-wave rectify the AC voltage; a voltage converter to receive the first full-wave rectified voltage from the rectifier, to generate a second full-wave rectified stepped-up voltage, and to generate a pulse enable signal; a pulse width modulation controller to receive the second full-wave rectified stepped-up voltage and to generate a pulse width modulation signal to dim an AC LED in response to the pulse enable signal; and a switch to drive the AC LED under control of the pulse width modulation signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An alternating current (AC) light-emitting diode (LED) dimming method, comprising:
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receiving AC voltage and generating a pulse width modulation signal; driving an AC LED under control of the pulse width modulation signal; and dimming the AC LED by adjusting a duty cycle of the pulse width modulation signal. - View Dependent Claims (16)
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15. An alternating current (AC) light-emitting diode (LED) dimming method, comprising:
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receiving AC voltage and first full-wave rectifying the AC voltage to generate first full-wave rectified voltage; generating second full-wave rectified stepped-up voltage from the first full-wave rectified voltage, and generating a pulse enable signal; generating a pulse width modulation signal from the second full-wave rectified stepped-up voltage and in response to the pulse enable signal; switching bidirectionally according to the AC voltage under control of the pulse width modulation signal to drive an AC LED; and dimming the AC LED by adjusting a duty cycle of the pulse width modulation signal. - View Dependent Claims (17)
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Specification