Provided is a system for reducing power consumption in digitally addressable lighting interfaces (DALI), the system including a processor having at least one pin, a transistor coupled to the processor and a resistive network coupled to the processor and the resistive network.

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 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 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 arranged to conduct current through a gate terminal of the thyristor, and a control circuit configured to control the gate coupling circuit. The control circuit may control 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 bidirectional switch switched to conduct and interrupt a bidirectional current between a pair of input terminals. An input device receives a dimming level representing a value of light output of the load. A controller controls the bidirectional switch according to the dimming level. The controller controls the bidirectional switch to keep the bidirectional switch in an off-state from a start point of a half cycle of the AC voltage of the AC power supply to a first time point when a first time period therefrom elapses, and to turn the bidirectional switch to an on-state at the first time point. The controller turns the bidirectional switch to the off-state at a second time point when a second time period elapses from the first time point. The controller keeps the bidirectional switch in the off-state from the second time point to an end point of the half cycle.

A dimmable ballast circuit for a compact fluorescent lamp controls the intensity of a lamp tube in response to a phase-control voltage received from a dimmer switch. The ballast circuit comprises a phase-control-to-DC converter circuit that receives the phase-control voltage, which is characterized by a duty cycle defining a target intensity of the lamp tube, and generates a DC voltage representative of the duty cycle of the phase-control voltage. Changes in the duty cycle of the phase-control voltage that are below a threshold amount are filtered out by the converter circuit, while intentional changes in the duty cycle of the phase-control voltage are reflected in changes in the target intensity level and thereby the intensity level of the lamp tube.

A load control device for controlling power delivered from an AC power source to an electrical load may have a closed-loop gate drive circuit for controlling a semiconductor switch of a controllably conductive device. The controllably conductive device may be coupled in series between the source and the load. The gate drive circuit may generate a target signal in response to a control circuit. The gate drive circuit may shape the target signal over a period of time and may increase the target signal to a predetermined level after the period of time. The gate drive circuit may receive a feedback signal that indicates a magnitude of a load current conducted through the semiconductor switch. The gate drive circuit may generate a gate control signal in response to the target signal and the feedback signal, and render the semiconductor switch conductive and non-conductive in response to the gate control signal.

A dimmable ballast circuit for a compact fluorescent lamp controls the intensity of a lamp tube in response to a phase-control voltage received from a dimmer switch. The ballast circuit comprises a phase-control-to-DC converter circuit that receives the phase-control voltage, which is characterized by a duty cycle defining a target intensity of the lamp tube, and generates a DC voltage representative of the duty cycle of the phase-control voltage. Changes in the duty cycle of the phase-control voltage that are below a threshold amount are filtered out by the converter circuit, while intentional changes in the duty cycle of the phase-control voltage are reflected in changes in the target intensity level and thereby the intensity level of the lamp tube.

A bidirectional switch switched to conduct and interrupt a bidirectional current between a pair of input terminals. An input device receives a dimming level representing a value of light output of the load. A controller controls the bidirectional switch according to the dimming level. The controller controls the bidirectional switch to keep the bidirectional switch in an off-state from a start point of a half cycle of the AC voltage of the AC power supply to a first time point when a first time period therefrom elapses, and to turn the bidirectional switch to an on-state at the first time point. The controller turns the bidirectional switch to the off-state at a second time point when a second time period elapses from the first time point. The controller keeps the bidirectional switch in the off-state from the second time point to an end point of the half cycle.