LIGHTING APPARATUS WITH INDUCTOR CURRENT LIMITING FOR NOISE REDUCTION
First Claim
Patent Images
1. A lighting apparatus comprising:
- a lighting circuit; and
a driver circuit having an output coupled to the lighting circuit and an input configured to be coupled to a power source that provides a varying voltage waveform, the driver circuit comprising an electromagnetic interference (EMI) filter inductor configured to be coupled in series with the power source and a bypass circuit configured to conduct a bypass current to thereby divert current from the EMI filter inductor for a first state of a voltage across the EMI filter inductor to limit a current in the EMI filter inductor and to terminate conduction of the bypass current for a second state of the voltage across the EMI filter inductor.
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Abstract
A lighting apparatus includes a lighting circuit (e.g., an LED lighting circuit) and a driver circuit having an output coupled to the lighting circuit and an input configured to be coupled to a power source, such as a phase cut dimmer, that provides a varying voltage waveform. The driver circuit includes an electromagnetic interference (EMI) suppression inductor configured to be coupled in series with the power source and a bypass circuit configured to divert current from the EMI filter inductor to limit a current in the EMI filter inductor.
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Citations
29 Claims
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1. A lighting apparatus comprising:
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a lighting circuit; and a driver circuit having an output coupled to the lighting circuit and an input configured to be coupled to a power source that provides a varying voltage waveform, the driver circuit comprising an electromagnetic interference (EMI) filter inductor configured to be coupled in series with the power source and a bypass circuit configured to conduct a bypass current to thereby divert current from the EMI filter inductor for a first state of a voltage across the EMI filter inductor to limit a current in the EMI filter inductor and to terminate conduction of the bypass current for a second state of the voltage across the EMI filter inductor. - View Dependent Claims (2, 3, 5, 6, 10, 11, 12, 13)
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4. The lighting apparatus 3, wherein the bypass circuit is configured to limit a magnitude of the voltage across the EMI filter inductor to a value less than a saturation threshold of the EMI inductor and greater than a maximum magnitude of the voltage across the EMI filter inductor when the power source is applying a non-phase cut AC waveform to the input of the driver circuit.
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7. A lighting apparatus comprising:
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a lighting circuit; and a driver circuit having an output coupled to the lighting circuit and an input configured to be coupled to a power source that provides a varying voltage waveform, the driver circuit comprising an electromagnetic interference (EMI) filter inductor configured to be coupled in series with the power source and a bypass circuit configured to divert current from the EMI filter inductor to limit a current in the EMI filter inductor, wherein the bypass circuit comprises a transient voltage suppressor (TVS) coupled in parallel with the EMI filter inductor. - View Dependent Claims (8)
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9. A lighting apparatus comprising:
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a lighting circuit; and a driver circuit having an output coupled to the lighting circuit and an input configured to be coupled to a power source that provides a varying voltage waveform, the driver circuit comprising an electromagnetic interference (EMI) filter inductor configured to be coupled in series with the power source and a bypass circuit configured to divert current from the EMI filter inductor to limit a current in the EMI filter inductor, wherein the bypass circuit comprises a series combination of a TVS and a resistor coupled in parallel with the EMI filter inductor.
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14. A lighting apparatus comprising:
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a lighting circuit; and a driver circuit having an output coupled to the lighting circuit and an input configured to be coupled to a dimmer, the driver circuit comprising an inductor coupled to the input and an inductor current limiter circuit configured to initiate a diversion of current from the EMI filter inductor and thereby limit a current in the inductor responsive to a leading edge of a phase cut voltage applied to the input. - View Dependent Claims (15, 16, 17, 18, 19, 20, 29)
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21. A driver circuit for a lighting apparatus, the driver circuit comprising:
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an inductor configured to be coupled to an AC power source; a capacitor coupled to the power source via the inductor; and a bypass circuit configured to divert current away from the inductor responsive to an edge of a phase cut voltage produced by the AC power source. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28)
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Specification