Patent attributes
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 comprising two MOS-gated transistors, and a control circuit. The control circuit generates first and second drive voltages for individually controlling the MOS-gated transistors, and controls the gate coupling circuit to cause the MOS-gated transistors to conduct a pulse of current through a gate terminal of the thyristor to render the thyristor conductive at a firing time during a present half cycle of the AC power source, and to allow the MOS-gated transistors to conduct at least one other pulse of current through the gate terminal after the firing time during the present half cycle.
