The present invention discloses a high power factor phase-cut dimming power supply system, which includes an alternating current power supply, a phase cutting dimmer, a high power factor phase-cut dimming power supply, an LED lamp, or an LED light. The high power factor phase-cut dimming power supply includes an anti-interference circuit that corresponds to and adaptively connect with each other, an active power factor correction circuit, a power conversion circuit, a dimmer current maintaining circuit, a signal conversion circuit, a photoelectric coupler, a PWM signal amplifying circuit and a field effect transistor. The present invention provides a high power factor phase-cut dimming power supply. It has advantages of a high power factor, a load power without any limitation, a high efficiency, an output power as high as several hundred watts. It can be widely used in the field of high power factor phase-cut dimming power supply.

A load control device coupled between an AC power source and an electrical load may operate in a three-wire mode or a two-wire mode based on whether the load control device is connected to a neutral side of the AC power source. The load control device may further comprise first and second zero-cross detect circuits to be respectively used in the two-wire mode or the three-wire mode, and a neutral wire detect circuit configured to generate a neutral-wire detect signal indicating whether the load control device is connected to the neutral side of the AC power source. A control circuit of the load control device may determine whether the load control device should operate in the two-wire mode or in the three-wire mode in response to the neutral-wire detect signal.

A microcontroller receives a LINE SYNC signal and a dimmer control voltage input and controls output switch timing of an output FET switch to generate a reverse phase PWM dimming signal for supply to associated LED driver apparatus.

The present disclosure provides an LED dimming driver circuit, which includes: a TRIAC dimmer configured to adjust an inputted alternating voltage; and a RCC connected to the TRIAC dimmer and configured to adjust the alternating voltage from the TRIAC dimmer to provide a driving current for an LED load.

In accordance with embodiments of the present disclosure, a method and apparatus includes an input having a first input terminal and a second input terminal for receiving an input waveform. In one example, the apparatus includes a capacitor having a first capacitor terminal and a second capacitor terminal, wherein the first capacitor terminal is coupled to the first input terminal, and at least one light-emitting diode coupled in series with the capacitor between the second capacitor terminal and the second input terminal, such that the light-emitting diode generates light in conformity with at least one of an amplitude modulation and a frequency modulation of the input waveform.

A multiple location dimming system may include a smart dimmer (e.g., a main load control device) and one or more remote dimmers (e.g., accessory devices) for controlling the amount of power delivered to a lighting load. The multiple location dimming system may be installed in place of a multiple location switch system (e.g., having three, four, or more multi-way switches), and may not require a neutral connection at any of the control devices of the multiple location dimming system. The main load control device and the accessory devices of the multiple location dimming system may be configured to display a present intensity level of a lighting load on one or more visual indicators. The accessory devices may have the same or different user interfaces as the main load control device, and may provide additional functionality over that which the main load control device offers.

A flyback converter is provided with a first output associated with a first secondary winding, a primary side controller arranged to maintain the first output at a predetermined voltage level and a second output associated with a second secondary windings; an LED controller. A first secondary electronically controlled switch is responsive to the LED controller; a first LED luminaire arranged to provide a first illumination responsive to a power signal on the second output when the first secondary electronically controlled switch is in a closed state and not provide the first illumination when the first secondary electronically controlled switch is in the open state, wherein the turns ratio of the first secondary winding and the second secondary winding is such that power is delivered to the first output via the first unidirectional electronic valve only when the first secondary electronically controlled switch is switched to the open state.

The invention describes an analog bleeder control arrangement (1) realized for use between a power supply (4) and a load (3), which bleeder control arrangement (1) is realized to generate a bleeder activation signal (20_on) to activate a bleeder (20) arranged between the power supply (4) and the load (3), and wherein the bleeder activation signal (20_on) is generated only upon detection of a phase-cut edge (LE, FE) on a voltage input signal (U.sub.in). The invention further describes an LED lamp driver (2), realized to drive a lighting load (3) comprising a number of LED light sources (30) and comprising such a bleeder control arrangement (1). The invention also describes a lighting arrangement (6) comprising an LED lighting load (3); a driver circuit (2) realized to drive the lighting load (3); a bleeder (20) for providing compatibility between a dimmer (5) and the driver (2); and such a bleeder control arrangement (1) realized to activate the bleeder (20) only upon detection of a phase-cut edge (LE, FE) on a power supply input signal (U.sub.in).

An audio output circuit of a condenser microphone includes a condenser microphone unit, first and second impedance conversion circuits that receive a positive phase output signal and a reverse phase output signal from the condenser microphone unit, first and second output circuits that output an audio signal from the condenser microphone unit in a balanced line to a balanced output terminals upon receipt of outputs of the first and second impedance conversion circuits. First and second impedance conversion circuits respectively use FETs as source follower circuits and supply first and second impedance conversion outputs generated across source resistors to the first and second output circuits. A voltage regulating device that generates a constant voltage is connected in series to the source resistors. With this configuration, an audio output circuit of a condenser microphone is provided, which solves a problem of operation instability caused by variation of Idss's of the FETs.

The present disclosure provides an LED dimming driver circuit, which includes: a TRIAC dimmer configured to adjust an inputted alternating voltage; and a RCC connected to the TRIAC dimmer and configured to adjust the alternating voltage from the TRIAC dimmer to provide a driving current for an LED load.