An impedance adjustment circuit varies an impedance of a transistor, thereby adjusting an impedance of a current path. A second control circuit controls a drive circuit to turn on or off at least one switch device of the switch devices while the impedance adjustment circuit is increasing the impedance of the current path. The impedance adjustment circuit adjusts the impedance of the current path to the minimum value after the drive circuit switches the at least one switch device from off to on or from on to off.

An impedance adjustment circuit varies an impedance of a transistor, thereby adjusting an impedance of a current path. A second control circuit controls a drive circuit to turn on or off at least one switch device of the switch devices while the impedance adjustment circuit is increasing the impedance of the current path. The impedance adjustment circuit adjusts the impedance of the current path to the minimum value after the drive circuit switches the at least one switch device from off to on or from on to off.

A light emitting diode driver (LED) circuit and method are provided. The light emitting diode driver circuit includes an LED array; a LED driving circuit configured to supply current to the LED array through switching operations of a plurality of switches; and a driving controller configured to control the plurality of switches to supply current, corresponding to a dimming signal, to the LED array using a clock signal of a preset frequency. The driving controller may be further configured to control the plurality of switches to alternately perform switching operations.

A light emitting diode driver (LED) circuit and method are provided. The light emitting diode driver circuit includes an LED array; a LED driving circuit configured to supply current to the LED array through switching operations of a plurality of switches; and a driving controller configured to control the plurality of switches to supply current, corresponding to a dimming signal, to the LED array using a clock signal of a preset frequency. The driving controller may be further configured to control the plurality of switches to alternately perform switching operations.

A filament for a light bulb includes a tube and a filament material within the tube, wherein the filament material is configured to be in a liquid state while the light bulb is in use.

A filament for a light bulb includes a tube and a filament material within the tube, wherein the filament material is configured to be in a liquid state while the light bulb is in use.

There is set forth herein a dimmer circuit for controlling delivery of input line voltage to a load. The dimmer circuit can include a switch coupling an input line voltage terminal to a load terminal. The dimmer circuit can be operative to provide one or more switch firing control scheme for latching the switch.

There is set forth herein a dimmer circuit for controlling delivery of input line voltage to a load. The dimmer circuit can include a switch coupling an input line voltage terminal to a load terminal. The dimmer circuit can be operative to provide one or more switch firing control scheme for latching the switch.

There is set forth herein a dimmer circuit for controlling delivery of input line voltage to a load. The dimmer circuit can include a switch coupling an input line voltage terminal to a load terminal. The dimmer circuit can be operative to provide one or more switch firing control scheme for latching the switch.

A zero-crossing detection circuit for a trailing edge phase control dimmer circuit for controlling alternating current (AC) power to a load, wherein the circuit includes: a switching circuit for controlling delivery of AC power to the load by conducting power to the load in an ON state and not conducting power to the load in an OFF state; a switching control circuit for controlling turn-OFF and turn-ON of the switching circuit at each cycle of the AC; and a rectifier for rectifying the AC power in the non-conduction period to generate rectified dimmer voltage to be provided to the dimmer circuit, wherein the zero-crossing detection circuit includes a current sink circuit; wherein the current sink circuit has a low impedance at low instantaneous AC voltages; a comparator circuit configured to detect zero crossings of a first threshold value of the rectified dimmer voltage.