Load control device for high-efficiency loads
First Claim
1. A load control device for controlling power delivered from an AC power source to an electrical load, the load control device comprising:
- a thyristor adapted to be electrically coupled between the AC power source and the electrical load, the thyristor having first and second main terminals through which current can be conducted to energize the electrical load and a gate terminal through which current can be conducted to render the thyristor conductive;
a first current path electrically coupled between the first main terminal of the thyristor and the gate terminal of the thyristor to conduct current through the gate terminal of the thyristor;
a control circuit configured to control the first current path to conduct a pulse of current through the gate terminal of the thyristor to render the thyristor conductive at a firing time during a present half-cycle of the AC power source, the control circuit being 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 thyristor again after the firing time until a transition time before the end of the present half-cycle; and
a second current path electrically coupled between the first and second terminals of the thyristor to conduct current through the electrical load between the transition time and the end of the present half-cycle.
2 Assignments
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 first current path for conducting current through a gate terminal of the thyristor, and a control circuit for controlling the first current path to conduct a pulse of current through the gate terminal to render the thyristor conductive at a firing time during a half cycle. The first current path is able to conduct at least one other pulse of current through the gate terminal again after the firing time until, a transition time before the end of the half-cycle, but prevented from conducting pulses of current after the transition time until the end of the half-cycle. The load control device may comprise a second current path for conducting current through the electrical load between the transition time and the end of the half-cycle.
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Citations
24 Claims
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1. A load control device for controlling 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 electrically coupled between the AC power source and the electrical load, the thyristor having first and second main terminals through which current can be conducted to energize the electrical load and a gate terminal through which current can be conducted to render the thyristor conductive; a first current path electrically coupled between the first main terminal of the thyristor and the gate terminal of the thyristor to conduct current through the gate terminal of the thyristor; a control circuit configured to control the first current path to conduct a pulse of current through the gate terminal of the thyristor to render the thyristor conductive at a firing time during a present half-cycle of the AC power source, the control circuit being 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 thyristor again after the firing time until a transition time before the end of the present half-cycle; and a second current path electrically coupled between the first and second terminals of the thyristor to conduct current through the electrical load between the transition 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)
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19. A load control device for controlling 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 electrically coupled between the AC power source and the electrical load, the thyristor having first and second main terminals through which current can be conducted to energize the electrical load and a gate terminal through which current can be conducted to render the thyristor conductive; a gate coupling circuit electrically coupled between the first main terminal and the gate terminal of the thyristor to conduct current through the gate terminal of the thyristor; a controllable switching circuit electrically coupled in parallel with the first and second main terminals of the thyristor; and a control circuit configured to render the gate coupling circuit conductive to conduct a pulse of current through the gate terminal of the thyristor to render the thyristor conductive at a firing time during a present half-cycle of the AC power source, the control circuit configured to control the gate coupling circuit to allow the gate coupling circuit to conduct at least one other pulse of current through the gate terminal of the thyristor again after the firing time until a transition time before the end of the present half-cycle; wherein the control circuit is configured to render the gate coupling circuit non-conductive between approximately the transition time and the end of the present half-cycle, the control circuit being configured to render the controllable switching circuit conductive to conduct current through the electrical load between approximately the transition time and the end of the present half-cycle. - View Dependent Claims (20, 21, 22, 23, 24)
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Specification