Patent attributes
A 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 (such as, a triac) coupled between the source and the load, a gate coupling circuit coupled to conduct current through a gate terminal of the thyristor, a controllable switching circuit coupled between the gate coupling circuit and the gate terminal of the thyristor, and a control circuit configured to control the gate coupling circuit and the controllable switching circuit. The control circuit may cause the gate coupling circuit to conduct a pulse of current through the gate terminal to render the thyristor conductive at a firing time during a present half cycle of the AC power source, and allow the gate coupling circuit to conduct at least one other pulse of current after the firing time during the present half cycle.
