A two-wire load control device (such as, a
dimmer switch) is operable to control the amount of power delivered from an
AC power source to an
electrical load (such as, a high-efficiency lighting load) and has substantially no minimum load requirement. The
dimmer switch includes a bidirectional
semiconductor switch, which is operable to be rendered conductive each half-cycle and to remain conductive independent of the magnitude of a load current conducted through
semiconductor switch. The
dimmer switch comprises a
control circuit that conducts a control current through the load in order to generate a gate drive
signal for rendering the bidirectional
semiconductor switch conductive and non-conductive each half-cycle. The
control circuit may provide a constant gate drive to the bidirectional semiconductor switch after the bidirectional semiconductor switch is rendered conductive each half-cycle. The bidirectional semiconductor switch may comprise, for example, a
triac or two field-effect transistors coupled in anti-series connection.