POWERING HIGH-EFFICIENCY LIGHTING DEVICES FROM A TRIAC-BASED DIMMER
First Claim
1. A circuit for powering one or more lighting devices from an output of a thyristor-switched dimmer circuit, comprising:
- a power converter having an input for coupling to the output of the thyristor-switched dimmer circuit and at least one output for supplying energy to the one or more lighting devices;
a control circuit having an input coupled to the output of the zero-crossing predicting circuit for determining an active time period for which the power converter transfers energy from the output of the thyristor-switched dimmer circuit, wherein subsequent to the active time period, a high impedance level is presented to the output of the thyristor-switched dimmer circuit during an idle period;
a zero-crossing predicting circuit for calculating a zero-cross time of a voltage of an AC power source coupled to an input of the thyristor-switched dimmer circuit; and
a timer coupled to the zero-crossing predicting circuit for triggering application of a glue impedance level to the output of the thyristor-switched dimmer circuit to terminate the idle period at a time substantially equal to the zero-cross time.
4 Assignments
0 Petitions
Accused Products
Abstract
A circuit for powering high-efficiency lighting devices from a thyristor-controlled dimmer predicts a zero-crossing time of the AC power line supplying the dimmer and causes a glue impedance to be imposed at the output of the dimmer starting at the time of the zero-crossing, so that the timer in the dimmer will operate properly to generate the turn-on event at the correct time. At turn-on, a lower level of impedance is presented to absorb the energy associated with the turn-on event. A higher level of impedance may be presented after the energy is absorbed until all of the energy needed for the cycle is transferred. Then, a high impedance state is maintained until the next zero-crossing time. The impedance control may be provided by non-uniform operation of a power converter that supplies the lighting devices, or by a combination of non-uniform power converter operation and dissipative loading.
70 Citations
30 Claims
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1. A circuit for powering one or more lighting devices from an output of a thyristor-switched dimmer circuit, comprising:
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a power converter having an input for coupling to the output of the thyristor-switched dimmer circuit and at least one output for supplying energy to the one or more lighting devices; a control circuit having an input coupled to the output of the zero-crossing predicting circuit for determining an active time period for which the power converter transfers energy from the output of the thyristor-switched dimmer circuit, wherein subsequent to the active time period, a high impedance level is presented to the output of the thyristor-switched dimmer circuit during an idle period; a zero-crossing predicting circuit for calculating a zero-cross time of a voltage of an AC power source coupled to an input of the thyristor-switched dimmer circuit; and a timer coupled to the zero-crossing predicting circuit for triggering application of a glue impedance level to the output of the thyristor-switched dimmer circuit to terminate the idle period at a time substantially equal to the zero-cross time. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of powering one or more lighting devices from an output of a thyristor-switched dimmer circuit, comprising:
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supplying energy to the one or more lighting devices by converting energy drawn from the output of the thyristor-switched dimmer circuit; determining an active time period for which the power converter transfers energy from the output of the thyristor-switched dimmer circuit; controlling an impedance presented to the output of the thyristor-switched dimmer circuit such that a higher impedance is presented to the output of the output of the thyristor-switched dimmer circuit during an idle period immediately subsequent to the active time period; predicting a zero-cross time of a voltage of an AC power source coupled to an input of the thyristor-switched dimmer circuit; and responsive to the predicting, applying a glue impedance level to the output of the thyristor-switched dimmer circuit to terminate the idle period at a time substantially equal to the zero-cross time. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. An integrated circuit for operating a circuit that powers one or more lighting devices from an output of a thyristor-switched dimmer circuit, comprising:
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a power converter control circuit having an input for coupling to the output of the thyristor-switched dimmer circuit and an output for controlling a power converter for supplying the one or more lighting devices from the output of the thyristor-switched dimmer circuit; an impedance control circuit having an input coupled to the output of the zero-crossing predicting circuit for determining an active time period for which the power converter transfers energy from the output of the thyristor-switched dimmer circuit, wherein subsequent to the active time period, a high impedance level is presented to the output of the thyristor-switched dimmer circuit during an idle period; a zero-crossing predicting circuit for calculating a zero-cross time of a voltage of an AC power source coupled to an input of the thyristor-switched dimmer circuit; and a timer coupled to the zero-crossing predicting circuit for triggering application of a glue impedance level to the output of the thyristor-switched dimmer circuit to terminate the idle period at a time substantially equal to the zero-cross time. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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22. A circuit for powering one or more lighting devices from an output of a thyristor-switched dimmer circuit, comprising:
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a power converter having an input for coupling to the output of the thyristor-switched dimmer circuit; a zero-crossing determining circuit for determining a zero-cross time of a voltage of an AC power source coupled to an input of the thyristor-switched dimmer circuit; and a control circuit having an input coupled to the output of the zero-crossing determining circuit for controlling operation of the power converter such that a greater amount of current is drawn from the thyristor-switched dimmer circuit through the power converter commencing at a first time substantially equal to a turn-on time of the thyristor-switched dimmer circuit than a lesser non-zero amount of current that is transferred commencing at a second time subsequent to the first time and prior to a next zero-cross time of the voltage of the AC power source. - View Dependent Claims (23, 24)
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25. A method of powering one or more lighting devices from an output of a thyristor-switched dimmer circuit, comprising:
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determining a zero-cross time of a voltage of an AC power source coupled to an input of the thyristor-switched dimmer circuit; supplying energy to the one or more lighting devices by converting energy drawn from the output of the thyristor-switched dimmer circuit using a power converter; and controlling the power converter such that a greater amount of current is drawn from the thyristor-switched dimmer circuit through the power converter commencing at a first time substantially equal to a turn-on time of the thyristor-switched dimmer circuit than a lesser non-zero amount of current that is transferred commencing at a second time subsequent to the first time and prior to a next zero-cross time of the voltage of the AC power source. - View Dependent Claims (26, 27)
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28. An integrated circuit for operating a circuit that powers one or more lighting devices from an output of a thyristor-switched dimmer circuit, comprising:
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a zero-crossing determining circuit for determining a zero-cross time of a voltage of an AC power source coupled to an input of the thyristor-switched dimmer circuit; and a power converter control circuit having an input for coupling to the output of the thyristor-switched dimmer circuit and an output for controlling a power converter for supplying the one or more lighting devices from the output of the thyristor-switched dimmer circuit, wherein the power converter control circuit controls operation of the power converter such that a greater amount of current is drawn from the thyristor-switched dimmer circuit through the power converter commencing at a first time substantially equal to a turn-on time of the thyristor-switched dimmer circuit than a lesser non-zero amount of current that is transferred commencing at a second time subsequent to the first time and prior to a next zero-cross time of the voltage of the AC power source. - View Dependent Claims (29, 30)
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Specification