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.

A power control device is provided for adjusting the input power to a device. The power control device includes an input, an output, and two or more output levels. A device such as an electrical device, appliance, or tool is attached to the output of the power control device. Further, a switch couples the input of the power control device to a power source. Thereby, the output level of the power control device can be adjusted by turning on and turning off the power source within a period of time.

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 coupled between a first main load terminal and the gate of the thyristor, and a control circuit coupled to a control input of the gate coupling circuit. The control circuit generates a drive voltage for causing the gate coupling circuit to conduct a gate current to thus render the thyristor conductive at a firing time during a half cycle of the AC power source, and to allow the gate coupling circuit to conduct the gate current at any time from the firing time through approximately the remainder of the half cycle, where the gate coupling circuit conducts approximately no net average current to render and maintain the thyristor conductive.

A light-emitting diode driving module includes an LED driving circuit to activate light-emitting diodes driven by a modified rectified voltage, and to adjust driving currents conducted to driving nodes to the light emitting diodes; a driving current controller to receive a dimming signal indicative of a degree of modulation of the rectified voltage, and to control currents conducted to the driving nodes depending on the dimming signal; and a current blocking circuit to block the currents of the driving nodes when a dimming level of the dimming signal decreases lower than a first threshold value, and unblock the currents of the driving nodes when the dimming level increases above a second threshold value higher than the first threshold value.

A method for generating a stable direct current signal, a silicon controlled switch dimming method and device, the silicon controlled switch dimming method comprising: adjusting a phase angle of a silicon controlled switch and outputting an alternating current signal related to the phase angle of the silicon controlled switch (S101); rectifying the alternating current signal (S102); converting the rectified electric signal into a steady direct current signal one-to-one corresponding to the phase angle of the silicon controlled switch, and the stable direct current signal decreases as the phase angle of a silicon controlled switch increases (S103); controlling turning on or off of an output current regulating circuit according to the magnitude of the stable direct current signal so as to control the plurality of serially connected LED lamp groups to be turned all on or all off (S104). The generated stable DC signal one-to-one corresponds to the phase angle of the silicon controlled switch and decreases with the increase of the phase angle of the silicon controlled switch. The stable direct current signal can control work status of the plurality of LED lamp groups connected in series, thereby making the plurality of LED lamp groups connected in series be turned all on or all off.

A bidirectional switch is switched so as to conduct and interrupt a bidirectional current between a pair of input terminals. A power supply is electrically connected between the pair of input terminals and produces control power by electric power from an AC power supply. A controller receives the control power from the power supply to be activated. The controller causes the bidirectional switch to be in an off-state from a start point of a half cycle of AC voltage to a first time point when first time elapses. The controller causes the bidirectional switch to be in an on-state from the first time point to a second time point when second time according to the dimming level elapses. The controller causes the bidirectional switch to be in an off-state from the second time point to an end point of the half cycle.

A bidirectional switch is switched so as to conduct and interrupt a bidirectional current between a pair of input terminals. A power supply is electrically connected between the pair of input terminals and produces control power by electric power from an AC power supply. A controller receives the control power from the power supply to be activated. The controller causes the bidirectional switch to be in an off-state from a start point of a half cycle of AC voltage to a first time point when a first time period elapses. The controller causes the bidirectional switch to be in an on-state from the first time point to a second time point when a second time period according to the dimming level elapses. The controller causes the bidirectional switch to be in an off-state from the second time point to an end point of the half cycle.

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 coupled between a first main load terminal and the gate of the thyristor, and a control circuit coupled to a control input of the gate coupling circuit. The control circuit generates a drive voltage for causing the gate coupling circuit to conduct a gate current to thus render the thyristor conductive at a firing time during a half cycle of the AC power source, and to allow the gate coupling circuit to conduct the gate current at any time from the firing time through approximately the remainder of the half cycle, where the gate coupling circuit conducts approximately no net average current to render and maintain the thyristor conductive.

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 coupled between a first main load terminal and the gate of the thyristor, and a control circuit coupled to a control input of the gate coupling circuit. The control circuit generates a drive voltage for causing the gate coupling circuit to conduct a gate current to thus render the thyristor conductive at a firing time during a half cycle of the AC power source, and to allow the gate coupling circuit to conduct the gate current at any time from the firing time through approximately the remainder of the half cycle, where the gate coupling circuit conducts approximately no net average current to render and maintain the thyristor conductive.

A light-emitting diode driving module includes an LED driving circuit to activate light-emitting diodes driven by a modified rectified voltage, and to adjust driving currents conducted to driving nodes to the light emitting diodes; a driving current controller to receive a dimming signal indicative of a degree of modulation of the rectified voltage, and to control currents conducted to the driving nodes depending on the dimming signal; and a current blocking circuit to block the currents of the driving nodes when a dimming level of the dimming signal decreases lower than a first threshold value, and unblock the currents of the driving nodes when the dimming level increases above a second threshold value higher than the first threshold value.