Ballast compatibility buffer circuit for LED lamps
First Claim
1. A light-emitting diode (LED) tube including a ballast compatible buffer circuit for interfacing with a ballast circuit and for driving a light-emitting diode LED load, the LED tube comprising:
- an LED driver circuit which includes;
first and second input terminals coupled to receive an ac input signal from the ballast circuit;
an input rectifier circuit coupled to receive the ac input signal and output a rectified voltage signal;
a switching regulator having an input side coupled to receive the rectified voltage signal, and an output side coupled to the LED load, the switching regulator including a regulator switch controlled by a controller that regulates transfer of energy to the LED load through an energy transfer element; and
the ballast compatible buffer circuit which includes;
first circuitry for detecting a high-frequency signal of the ballast circuit, the first circuitry generating a bypass control signal responsive to the high-frequency signal;
a bypass switching device coupled to the output side of the switching regulator, responsive to the bypass control signal the bypass switching device being activated to bypass the high-frequency signal away from the energy transfer element.
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Accused Products
Abstract
A light-emitting diode (LED) tube including a ballast compatible buffer circuit for interfacing with a ballast circuit and for driving a light-emitting diode LED tube. The LED tube includes an LED driver circuit with first and second input terminals coupled to receive an ac input signal from the ballast circuit, an input rectifier circuit coupled to receive the ac input signal and output a rectified voltage signal, a switching regulator including a regulator switch controlled by a controller that regulates transfer of energy to the LED load through an energy transfer element and the ballast compatible buffer circuit.
5 Citations
19 Claims
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1. A light-emitting diode (LED) tube including a ballast compatible buffer circuit for interfacing with a ballast circuit and for driving a light-emitting diode LED load, the LED tube comprising:
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an LED driver circuit which includes; first and second input terminals coupled to receive an ac input signal from the ballast circuit; an input rectifier circuit coupled to receive the ac input signal and output a rectified voltage signal; a switching regulator having an input side coupled to receive the rectified voltage signal, and an output side coupled to the LED load, the switching regulator including a regulator switch controlled by a controller that regulates transfer of energy to the LED load through an energy transfer element; and the ballast compatible buffer circuit which includes; first circuitry for detecting a high-frequency signal of the ballast circuit, the first circuitry generating a bypass control signal responsive to the high-frequency signal; a bypass switching device coupled to the output side of the switching regulator, responsive to the bypass control signal the bypass switching device being activated to bypass the high-frequency signal away from the energy transfer element. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A light-emitting diode (LED) tube for interfacing with a ballast circuit and for driving a light-emitting diode LED load, the LED tube comprising:
an LED driver circuit which includes; first and second input terminals coupled to receive an ac input signal from the ballast circuit; an input rectifier circuit coupled to receive the ac input signal and output a rectified voltage signal; a switching regulator having an input side coupled to receive the rectified voltage signal, and output side that outputs a regulated output signal to the LED load, the output side including an energy transfer element that regulates transfer of energy to the LED load; and a ballast compatible buffer circuit connected directly across the first and second input terminals, the ballast compatible buffer circuit including first circuitry for bypassing a high-frequency signal produced by the ballast circuit to a ground return line. - View Dependent Claims (16, 17, 18)
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19. A method of operation for a ballast compatible buffer circuit for use in a light-emitting diode (LED) driver interfacing with an electronic ballast circuit that generates high-frequency signals, the method comprising:
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filtering the high-frequency signals to generate a control signal therefrom; and applying the control signal to a bypass switching device, thereby causing the bypass switching device to close a direct bypassing path for the high frequency signals from an output of the LED driver to an ac input return line.
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Specification