Load control device for high-efficiency loads
First Claim
1. A load control device for controlling the amount of power delivered from an AC power source to an electrical load, the load control device comprising:
- a thyristor adapted to be coupled in series electrical connection between the AC power source and the electrical load for conducting a load current from the AC power source to the electrical load, the thyristor having a gate for conducting a gate current to render the thyristor conductive;
a first circuit coupled to the gate of the thyristor for conducting the gate current when the first circuit is conductive;
a second circuit coupled to conduct the load current when the thyristor is non-conductive; and
a control circuit operatively coupled to the first and second circuits for individually rendering the first and second circuits conductive and non-conductive, the control circuit configured to render the first circuit conductive to conduct the gate current to render the thyristor conductive at a firing time during a half cycle of the AC power source, the control circuit continuing to control the first circuit to be able to conduct the gate current again after the firing time;
wherein the control circuit is configured to render the first circuit non-conductive before the end of the half-cycle, such that the first circuit is not able to conduct the gate current through the gate of the thyristor and thereby allowing the thyristor to become non-conductive before the end of the half-cycle, the control circuit configured to control the second circuit to be conductive to conduct the load current after the thyristor becomes non-conductive.
1 Assignment
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Accused Products
Abstract
A two-wire load control device (such as, a dimmer switch) for controlling the amount of power delivered from an AC power source to an electrical load (such as, a high-efficiency lighting load) includes a thyristor coupled between the source and the load, a gate coupling circuit coupled between a first main load terminal and the gate of the thyristor, and a control circuit coupled to a control input of the gate coupling circuit. The control circuit generates a drive voltage for causing the gate coupling circuit to conduct a gate current to thus render the thyristor conductive at a firing time during a half cycle of the AC power source, and to allow the gate coupling circuit to conduct the gate current at any time from the firing time through approximately the remainder of the half cycle, where the gate coupling circuit conducts approximately no net average current to render and maintain the thyristor conductive.
77 Citations
20 Claims
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1. A load control device for controlling the amount of power delivered from an AC power source to an electrical load, the load control device comprising:
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a thyristor adapted to be coupled in series electrical connection between the AC power source and the electrical load for conducting a load current from the AC power source to the electrical load, the thyristor having a gate for conducting a gate current to render the thyristor conductive; a first circuit coupled to the gate of the thyristor for conducting the gate current when the first circuit is conductive; a second circuit coupled to conduct the load current when the thyristor is non-conductive; and a control circuit operatively coupled to the first and second circuits for individually rendering the first and second circuits conductive and non-conductive, the control circuit configured to render the first circuit conductive to conduct the gate current to render the thyristor conductive at a firing time during a half cycle of the AC power source, the control circuit continuing to control the first circuit to be able to conduct the gate current again after the firing time; wherein the control circuit is configured to render the first circuit non-conductive before the end of the half-cycle, such that the first circuit is not able to conduct the gate current through the gate of the thyristor and thereby allowing the thyristor to become non-conductive before the end of the half-cycle, the control circuit configured to control the second circuit to be conductive to conduct the load current after the thyristor becomes non-conductive. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A load control device for controlling the amount of power delivered from an AC power source to an electrical load, the load control device comprising:
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a thyristor adapted to be coupled in series electrical connection between the AC power source and the electrical load for conducting a load current from the AC power source to the electrical load, the thyristor having a gate for conducting a gate current to render the thyristor conductive; a semiconductor-switch circuit comprising a semiconductor switch coupled in parallel with the thyristor; and a control circuit operatively coupled to the gate of the thyristor for rendering the thyristor conductive at a firing time during a half cycle of the AC power source, the control circuit configured to maintain the thyristor conductive after the firing time and to allow the thyristor to become non-conductive before the end of the half cycle; wherein the control circuit is operatively coupled to the semiconductor switch of the semiconductor-switch circuit for rendering the semiconductor switch conductive and non-conductive, the control circuit configured to render the semiconductor switch conductive, such that the semiconductor switch is able to conduct the load current when the thyristor is non-conductive. - View Dependent Claims (17, 18, 19, 20)
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Specification