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 gate coupling circuit coupled to conduct the gate current through the gate of the thyristor; and
a control circuit operable to control 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 of the AC power source, the control circuit continuing to control the gate coupling circuit, such that the gate coupling circuit is able to conduct the gate current through the first current path again after the firing time;
wherein the gate current is not able to be conducted through the gate of the thyristor from a transition time before the end of the half-cycle until approximately the end of the half-cycle, the load current able to be conducted from the AC power source to the electrical load through a second current path after the transition time until approximately the end of the half-cycle.
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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.
84 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 gate coupling circuit coupled to conduct the gate current through the gate of the thyristor; and a control circuit operable to control 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 of the AC power source, the control circuit continuing to control the gate coupling circuit, such that the gate coupling circuit is able to conduct the gate current through the first current path again after the firing time; wherein the gate current is not able to be conducted through the gate of the thyristor from a transition time before the end of the half-cycle until approximately the end of the half-cycle, the load current able to be conducted from the AC power source to the electrical load through a second current path after the transition time until approximately the end of the half-cycle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. 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 having first and second main load terminals 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 gate coupling circuit coupled between the first main load terminal and the gate of the thyristor to conduct the gate current through the gate of the thyristor; a controllable switching circuit coupled in parallel electrical connection with the thyristor; and a control circuit operatively coupled to the gate coupling circuit and the controllable switching circuit, the control circuit operable to render the gate coupling 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 render the gate coupling circuit conductive, such that the gate coupling circuit is able to conduct the gate current again after the firing time; wherein the control circuit renders the gate current coupling circuit non-conductive at a transition time after the firing time and before the end of the half-cycle, the control circuit rendering the controllable switching circuit conductive at approximately the transition time, such that the controllable switching circuit is able to conduct the load current after the transition time until approximately the end of the half-cycle. - View Dependent Claims (18, 19, 20)
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Specification