Load control device for high-efficiency loads
First Claim
1. A dimmer switch for controlling an amount of power delivered from an AC power source to a lighting load for controlling an intensity of the lighting load, the dimmer switch comprising:
- a triac adapted to be electrically coupled between the AC power source and the lighting load, the triac having first and second main terminals through which current can be conducted to energize the lighting load and a gate terminal through which current can be conducted to render the triac conductive;
a first current path electrically coupled between the first main terminal of the triac and the gate terminal of the triac to conduct current through the gate terminal of the triac;
a control circuit configured to control the first current path to conduct a pulse of current through the gate terminal of the triac to render the triac conductive at a firing time during a present half-cycle of an AC mains voltage of the AC power source, the control circuit configured to control the first current path to allow the first current path to conduct at least one other pulse of current through the gate terminal of the triac again after the firing time until a second time before the end of the present half-cycle, the control circuit configured to control the firing time to adjust the intensity of the lighting load; and
a second current path electrically coupled between the first and second terminals of the triac to conduct current through the lighting load between the second time and the end of the present half-cycle.
1 Assignment
0 Petitions
Accused Products
Abstract
A load control device for controlling the power delivered from an AC power source to an electrical load includes a thyristor, a gate coupling circuit for conducting a gate current through a gate of the thyristor, and a control circuit for controlling the gate coupling circuit to conduct the gate current through a first current path to render the thyristor conductive at a firing time during a half cycle. The gate coupling circuit is able to conduct the gate current through the first current path again after the firing time, but the gate current is not able to be conducted through the gate from a transition time before the end of the half-cycle until approximately the end of the half-cycle. The load current is able to be conducted through a second current path to the electrical load after the transition time until approximately the end of the half-cycle.
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Citations
20 Claims
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1. A dimmer switch for controlling an amount of power delivered from an AC power source to a lighting load for controlling an intensity of the lighting load, the dimmer switch comprising:
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a triac adapted to be electrically coupled between the AC power source and the lighting load, the triac having first and second main terminals through which current can be conducted to energize the lighting load and a gate terminal through which current can be conducted to render the triac conductive; a first current path electrically coupled between the first main terminal of the triac and the gate terminal of the triac to conduct current through the gate terminal of the triac; a control circuit configured to control the first current path to conduct a pulse of current through the gate terminal of the triac to render the triac conductive at a firing time during a present half-cycle of an AC mains voltage of the AC power source, the control circuit configured to control the first current path to allow the first current path to conduct at least one other pulse of current through the gate terminal of the triac again after the firing time until a second time before the end of the present half-cycle, the control circuit configured to control the firing time to adjust the intensity of the lighting load; and a second current path electrically coupled between the first and second terminals of the triac to conduct current through the lighting load between the second time and the end of the present half-cycle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A dimmer switch for controlling an amount of power delivered from an AC power source to a lighting load for controlling an intensity of the lighting load, the dimmer switch comprising:
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a triac adapted to be electrically coupled between the AC power source and the lighting load, the triac having first and second main terminals through which current can be conducted to energize the lighting load and a gate terminal through which current can be conducted to render the triac conductive; a first current path electrically coupled between the first main terminal of the triac and the gate terminal of the triac to conduct current through the gate terminal of the triac; a second current path electrically coupled between the first and second terminals of the triac; and a control circuit configured to control the first current path to conduct a pulse of current through the gate terminal of the triac to render the triac conductive at a firing time during a present half-cycle of an AC mains voltage of the AC power source, the control circuit configured to control the first current path to allow the first current path to conduct at least one other pulse of current through the gate terminal of the triac between the firing time and a second time that occurs before the end of the present half-cycle, the control circuit configured to control the firing time to adjust the intensity of the lighting load; wherein the control circuit is configured to prevent the first current path from conducting pulses of current through the gate terminal of the triac between the second time and the end of the present half-cycle to allow the triac to become non-conductive and remain non-conductive until the end of the present half-cycle, the second current path being configured to conduct current through the lighting load if the triac becomes non-conductive and remains non-conductive during the present half-cycle.
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Specification