System and method for driving light emitting diodes
First Claim
1. A system for driving light emitting diodes (LED), the system comprising:
- an alternating current (AC) driven LED unit, the AC driven LED unit comprising a first LED and a second LED, the first LED and the second LED being coupled in reverse parallel;
an alternating current voltage regulator coupled between an AC voltage source and the AC driven LED unit; and
a controller coupled to the AC voltage regulator, the controller configured to monitor AC voltage fluctuations of the AC voltage source and a regulated AC voltage supplied to the AC driven LED unit, and transmit control signals to the AC voltage regulator according to a monitored result,wherein the AC voltage regulator is operable to receive an AC voltage originating from the AC voltage source, and the AC voltage regulator is operable to regulate the AC voltage from the AC voltage source in response to the control signals transmitted from the controller, and to apply the regulated AC voltage to the AC driven LED unit, allowing the first LED and the second LED to emit light according to the regulated AC voltage;
the controller is configured to monitor the AC voltage source for voltage fluctuation of the AC voltage from the AC voltage source and generate a first control signal to control the AC voltage regulator to maintain the regulated AC voltage from the AC voltage regulator supplied to the AC driven LED unit at a predetermined level; and
the controller is configured to monitor the AC driven LED unit to monitor a voltage fluctuation of the regulated AC voltage from the AC voltage regulator and generate a second control signal to control the AC voltage regulator to maintain the regulated AC voltage at the predetermined level.
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Accused Products
Abstract
A system having an alternating current (AC) driven LED unit, an AC voltage regulator, and a controller is provided. The AC driven LED unit includes a first LED and a second LED coupled in reverse parallel. The AC voltage regulator is operable to receive AC voltage originating from an AC voltage source, regulate the AC voltage according to control signals from the controller, and apply regulated AC voltage to the AC driven LED unit, so as to enable the first LED and the second LED to emit light according to the regulated AC voltage. In addition, a method is provided for driving the LED by regulating the AC voltage. By regulating the AC voltage using the AC voltage regulator, benefits of restraining voltage fluctuations, reducing THD, improving power factor, providing dimming control, and mitigating flicker phenomenon can be achieved.
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Citations
20 Claims
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1. A system for driving light emitting diodes (LED), the system comprising:
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an alternating current (AC) driven LED unit, the AC driven LED unit comprising a first LED and a second LED, the first LED and the second LED being coupled in reverse parallel; an alternating current voltage regulator coupled between an AC voltage source and the AC driven LED unit; and a controller coupled to the AC voltage regulator, the controller configured to monitor AC voltage fluctuations of the AC voltage source and a regulated AC voltage supplied to the AC driven LED unit, and transmit control signals to the AC voltage regulator according to a monitored result, wherein the AC voltage regulator is operable to receive an AC voltage originating from the AC voltage source, and the AC voltage regulator is operable to regulate the AC voltage from the AC voltage source in response to the control signals transmitted from the controller, and to apply the regulated AC voltage to the AC driven LED unit, allowing the first LED and the second LED to emit light according to the regulated AC voltage; the controller is configured to monitor the AC voltage source for voltage fluctuation of the AC voltage from the AC voltage source and generate a first control signal to control the AC voltage regulator to maintain the regulated AC voltage from the AC voltage regulator supplied to the AC driven LED unit at a predetermined level; and the controller is configured to monitor the AC driven LED unit to monitor a voltage fluctuation of the regulated AC voltage from the AC voltage regulator and generate a second control signal to control the AC voltage regulator to maintain the regulated AC voltage at the predetermined level. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A system for driving an alternating current (AC) driven LED unit with an AC voltage originating from an AC voltage source, the AC driven LED unit having a first LED and a second LED arranged in reverse parallel, the system comprising:
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an alternating current (AC) voltage regulator, the AC voltage regulator being operable to receive the AC voltage originating from the AC voltage source, and to modulate the received AC voltage with pulse signals, a voltage level of the modulated AC voltage being adjusted by varying a duty cycle of the pulse signals to achieve a first dimming control of the first LED and the second LED; a phase-cut dimming circuit coupled to the AC voltage regulator, the phase-cut dimming circuit being operable to change a conduction angle of the received AC voltage to achieve a second dimming control of the first LED and the second LED; and a controller, the controller configured to receive a first feedback control signal from the AC voltage source indicating a voltage fluctuation of the AC voltage from the AC voltage source and generate a first control signal to the AC voltage regulator to maintain the modulated AC voltage at a predetermined level; the controller configured to receive a second feedback control signal from the AC driven LED unit indicating a voltage fluctuation of the regulated AC voltage from the AC voltage regulator and generate a second control signal to the AC voltage regulator to maintain the modulated AC voltage at the predetermined level. - View Dependent Claims (13)
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14. A method for driving an alternating current (AC) driven light emitting diodes (LED) unit, the AC driven LED unit comprising a first LED and a second LED, the first LED and the second LED being coupled in reverse parallel, the method comprising:
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receiving an AC voltage originating from an AC voltage source and generating a regulated AC voltage from an AC voltage regulator; using a controller to monitor fluctuations of the received AC voltage and the regulated AC voltage; applying the regulated AC voltage to the AC driven LED unit to drive the first LED and the second LED to emit light; wherein monitoring fluctuations of the received AC voltage and the regulated AC voltage by the controller comprises; receiving a first feedback control signal from the AC voltage source indicating a voltage fluctuation of the AC voltage from the AC voltage source and generating a first control signal to the AC voltage regulator to maintain the regulated AC voltage from the AC voltage regulator at a predetermined level; and receiving a second feedback control signal from the AC driven LED unit to monitor a voltage fluctuation of the regulated AC voltage and generating a second control signal to the AC voltage regulator to maintain the regulated AC voltage at the predetermined level. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification