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Load control device for high-efficiency loads

  • US 10,447,171 B2
  • Filed: 11/12/2018
  • Issued: 10/15/2019
  • Est. Priority Date: 11/25/2009
  • Status: Active Grant
First Claim
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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:

  • 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 between the first and second main terminals;

    a gate coupling circuit electrically coupled to the first main terminal of the triac and arranged to conduct current through the gate terminal of the triac;

    a controllable switching circuit electrically coupled in series between the gate coupling circuit and the gate terminal of the triac and configured to conduct current through the gate terminal of the triac; and

    a control circuit configured to render the controllable switching circuit conductive and to control the gate coupling circuit to conduct a pulse of current through the gate terminal of the triac at a firing time during a present half-cycle of an AC mains voltage of the AC power source to render the triac conductive, the control circuit configured to control the firing time to adjust the intensity of the lighting load;

    wherein the control circuit is 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 triac after the firing time during the present half-cycle, the control circuit further configured to render the controllable switching circuit non-conductive before the end of the present half-cycle to prevent any further pulses of current from being thereafter conducted through the gate terminal of the triac during the present half-cycle.

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