Adaptive current limiter and dimmer system including the same
First Claim
1. An adaptive current limiter for use in a power conversion system having a dimmer circuit for turning off a cyclic signal during a portion of a phase thereof to form a phase-cut signal, comprising:
- a sense resistor including a first sense terminal coupled to a power supply terminal and a second sense terminal, the sense resistor to generate a sense voltage in response to a feedback current;
a current pass transistor including a first terminal for receiving an input current, a second terminal coupled to the second sense terminal, and a control terminal; and
a controller coupled to the sense resistor and to the control terminal, the controller for sensing a beginning of a turn-on phase of the phase-cut signal, and responsive to the sensing for limiting the feedback current conducted by the current pass transistor during the beginning of the turn-on phase of the phase-cut signal.
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Accused Products
Abstract
In an embodiment, an adaptive current limiter includes a sense element, a current pass element, and a controller. The sense element includes a first sense terminal coupled to a power supply terminal and a second sense terminal. The sense element generates a sense voltage in response to a feedback current. The current pass element includes a first terminal for receiving the feedback current, a second terminal coupled to the second sense terminal, and a control terminal. The controller is coupled to the sense element and to the control terminal for adjusting the feedback current conducted by the current pass element based on the sense voltage and a time-varying voltage signal.
22 Citations
20 Claims
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1. An adaptive current limiter for use in a power conversion system having a dimmer circuit for turning off a cyclic signal during a portion of a phase thereof to form a phase-cut signal, comprising:
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a sense resistor including a first sense terminal coupled to a power supply terminal and a second sense terminal, the sense resistor to generate a sense voltage in response to a feedback current; a current pass transistor including a first terminal for receiving an input current, a second terminal coupled to the second sense terminal, and a control terminal; and a controller coupled to the sense resistor and to the control terminal, the controller for sensing a beginning of a turn-on phase of the phase-cut signal, and responsive to the sensing for limiting the feedback current conducted by the current pass transistor during the beginning of the turn-on phase of the phase-cut signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A current limiter circuit for use in a power conversion system having a dimmer circuit for turning off a cyclic signal during a portion of a phase thereof to form a phase-cut signal, comprising:
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a current pass transistor including a first current electrode adapted to couple to a load circuit to receive a feedback current, a second current electrode, and a control electrode; a sense resistor including a first sense terminal adapted to couple to a power supply terminal and a second sense terminal coupled to the second current electrode of the current pass transistor, the sense resistor for generating a sense voltage proportional to the feedback current; and a controller coupled to the sense resistor and to the control electrode, the controller for sensing a beginning of a turn-on phase of the phase-cut signal and responsive to the sensing to controllably increase a current conducted by the current pass transistor at the beginning of the turn-on phase of the phase-cut signal. - View Dependent Claims (11, 12, 13, 14)
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15. A phase-cut dimmer system comprising:
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first and second supply terminals; a phase-cut dimmer circuit adapted to be coupled to an alternating current (AC) power supply for generating a phase-cut signal by turning off the AC power supply during a portion of a phase thereof; a full-wave rectifier coupled to the phase-cut dimmer circuit for generating a rectified version of the phase-cut signal, the full-wave rectifier coupled to the first and second supply terminals for providing a rectified power supply; an electromagnetic interference (EMI) filter coupled to the first and second supply terminals; and a current limiter circuit coupled to the second supply terminal and to the EMI filter, the current limiter circuit responsive to a feedback current to sense a beginning of a turn-on phase of a phase-cut signal and responsive to the sensing to adjust the feedback current at the beginning of the turn-on phase of the phase-cut signal. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification