574 results about "TRIAC" patented technology

Exemplary embodiments provide an impedance matching circuit for providing variable power from a dimmer switch having a triac to a switching power supply couplable to solid-state lighting. An exemplary impedance matching circuit includes a first resistor coupled to receive a first current from the switching power supply; a second resistor; and a transistor coupled in series to the second resistor, with the transistor responsive to a gate voltage to modulate a second current through the second resistor in response to a detected level of the first current through the first resistor.

An exemplary embodiment provides a current regulator for controlling variable brightness levels for solid state lighting. The current regulator is couplable to a phase-modulating switch, such as a dimmer switch, which is coupled to an AC line voltage. An exemplary current regulator includes a rectifier; a switching power supply providing a first current; an impedance matching circuit; and a controller. The impedance matching circuit is adapted to provide a second current through the phase-modulating switch when a magnitude of the first current is below a first predetermined threshold, such as a holding current of a triac of the phase-modulating switch. The controller is adapted to determine a root-mean-square (RMS) voltage level provided by the phase-modulating switch from the AC line voltage and to determine a duty cycle for pulse-width current modulation by the switching power supply in response to the comparison of the RMS voltage level to a nominal voltage level.

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.

A thermostat is operable from battery, common-wire (“C-wire”), or furnace relay power. The thermostat includes a power source selector, such as a jumper wire, that is set when the thermostat is installed in a heating system. In a gas millivolt heating system, the thermostat operates off of battery power. In heating systems having a C-wire, a diode bridge converter converts alternating-current voltage to direct-current voltage to provide operating power to the thermostat. In heating systems without a C-wire and having sufficient furnace relay current, a triac converter in series with the furnace relay provides voltage spikes to the diode bridge converter to provide operating power to the thermostat when the furnace is on, and the diode bridge converts AC to DC voltage when the furnace is not on. The thermostat can also be used in cooling systems and heating, ventilation, and air-conditioning systems. Thus, the thermostat can be used in a wide variety of applications.

A provided smart switch called Occupant Counter Control Switch, or OCCS, basically comprises of a motion sensor PIR, a photo sensor, an amplifier with band-pass filter, a microprocessor, a digital display, and a relay or triac to drive electrical appliances such as lights. The PIR sensor detects heat from a human body moving across it and generates a distinctive signal that is, unique to each of the two directions, further processed by the microprocessor for counting and thereby controlling the relay. Installed at the entrance of a room replacing the regular switch (see FIG. 1), the OCCS counts up, displaying a digit great than zero, upon detecting a person entering the room and turns on the lights if sensing insufficient ambient light. OCCS constantly energizes the lights during the room is occupied and immediately switches them off upon counting down to zero when detecting the last person exiting the room.

A lighting system for operation with a dimmer circuit comprising a triac connected to a load. The load comprises a driver circuit for supplying current to a light source comprising one or more LEDs, the current being determined at least in part by an adjusted setpoint value. The system further comprises a setpoint filter circuit for obtaining a dimmer setpoint value determined at least in part by a setting of the dimmer circuit, and for generating an adjusted setpoint value. The sensitivity of the adjusted setpoint value to changes in the dimmer setpoint value is low at low values of the dimmer setpoint value.

A system and method includes a controller that is configured to coordinate (i) a low impedance path for a dimmer current, (ii) attaching a dimmer to a power converter system at the leading edge of a phase-cut, rectified input voltage, (iii), control of switch mode power conversion, and (iv) an inactive state to, for example, reduce the dimmer current while allowing a dimmer to function normally from cycle to cycle of an alternating current (AC) supply voltage. In at least one embodiment, the dimmer functions normally when the dimmer conducts at a correct phase angle indicated by a dimmer input setting and avoids prematurely resetting while conducting. In at least one embodiment, by coordinating functions (i), (ii), (iii), and (iv) the controller controls a power converter system that is compatible with a triac-based dimmer.

A circuit for powering high-efficiency lighting devices from a thyristor-controlled dimmer predicts a zero-crossing time of the AC power line supplying the dimmer and causes a glue impedance to be imposed at the output of the dimmer starting at the time of the zero-crossing, so that the timer in the dimmer will operate properly to generate the turn-on event at the correct time. At turn-on, a lower level of impedance is presented to absorb the energy associated with the turn-on event. A higher level of impedance may be presented after the energy is absorbed until all of the energy needed for the cycle is transferred. Then, a high impedance state is maintained until the next zero-crossing time. The impedance control may be provided by non-uniform operation of a power converter that supplies the lighting devices, or by a combination of non-uniform power converter operation and dissipative loading.

Enhanced active preload circuits for an LED driver implementing phase-angle dimming are disclosed. The enhanced active preload circuits may be used with any type of phase-angle control dimmer that either controls the leading edge or trailing edge of the line voltage cycle. In one example, the enhanced active preload circuitry may be used with an isolated or non-isolated LED driver converter having a Triac leading edge phase-angle control dimmer by directly sensing (e.g., by sensing the dimming level using an output/load voltage signal or output/load current signal) or indirectly sensing (e.g., by sensing a signal of output or bias winding) the Triac conduction angle. The enhanced active preload circuitry may advantageously improve performance of the LED driver by extending the dimming ratio at deep dimming and by adjusting the preload sinking current in response to a preload control signal.

A power supply circuit for operating high-efficiency lighting devices from a thyristor-controlled dimmer determines the dimming value, i.e., the dimmer duty factor by periodically probing the dimmer output. A minimum conductance is applied across the output of the dimmer during probing intervals that begin at the turn-on time of the dimmer and last until enough information has been gathered to correctly predict a next zero crossing of the AC line voltage that supplies the input of the dimmer. The dimming value is determined from the time interval between the predicted zero-crossing and a next turn-on time of the dimmer. The probing can be performed at intervals of an odd number of half-cycles of the AC line frequency so that a DC offset is not introduced within internal timing circuits of the dimmer. The AC line frequency can also be determined from a time interval between the predicted zero crossings.

Apparatus and associated methods relate to a diversion driver module that dynamically adds a diversion current to an LED current so that the summed current maintains a predetermined minimum holding current requirement of a phase-controlled dimmer supply. In an illustrative example, the diversion current may be a function of input AC line voltage and/or firing angle of the phase-controlled dimmer supply. The phase controlled device may include, for example, a triac. The triac may supply adjustable pulse-width current to dim the LED according to a phase control signal. The diversion driver module may include one or more heat dissipating components disposed in thermal communication with the lamp base. Some driver modules may be sufficiently compact and energy efficient to provide smooth dim-to-black performance while operating within acceptable temperature limits for reliable operation while contained in the base of a standard form factor lamp, such as an E12 full-glass lamp.

An LED dimming circuit suitable for thyristor dimmers, 50/60Hz AC sine wave waveforms are chopped by a triac (TRIAC), rectified by a bridge rectifier circuit (A), and separated by an isolation circuit ( U1) Take out the chopping waveform and send it to the single-chip control unit (MCU), the single-chip control unit (MCU) outputs the PWM waveform to the LED driver chip (LEDDRIVE), and the LED driver chip (LEDDRIVE) drives the light-emitting diodes (LED1, LED2) to emit light. It makes the LED lamp directly replace the incandescent lamp with the same perfect dimming effect, and the circuit is simple and the cost is low, which overcomes an important obstacle for the LED lamp to replace the incandescent lamp.

A bleeder circuit is provided in a switched mode power supply (SMPS) that provides a compensation current when the loop current drops below the holding current of the TRIAC to alleviate light flickering problem. Further, automatic power factor correction is also provided in embodiments of the invention, which enables the output current to be in phase with the input voltage. The power factor correction not only improves the efficiency of the power supply, it can also reduce the compensation current and the duration in which compensation current flows, thereby reducing the power loss in the bleeder circuit.

System controller and method for a lighting system. The system controller includes a first controller terminal configured to receive a first signal, and a second controller terminal configured to output a second signal to a diver component. The driver component is configured to receive a first current and provide one or more drive currents to one or more light emitting diodes in response to the second signal. Additionally, the system controller is configured to process information associated with the first signal, determine a first time period for the first signal to increase from a first threshold to a second threshold, and determine a second time period for the first signal to decrease from the second threshold to the first threshold.

A TRIAC/SCR-based energy savings device, system and method (1) wherein a predetermined amount of voltage below a nominal line voltage and/or below a nominal appliance voltage is saved, thereby conserving energy. Phase input connections (2) are provided for inputting analog signals into the device and system (1). A magnetic flux concentrator (3) senses the incoming analog signal (20) and a volts zero crossing point detector (5) determines the zero volts crossing point (21) of the signal (20). The positive half cycle (22) and negative half cycle (23) of the signal (20) are identified and routed to a digital signal processor (10) for processing the signal (20). The signal (20) is reduced by pulse width modulation and the reduced amount of energy is outputted, thereby yielding an energy savings for an end user.

The present disclosure discloses a bleeder circuit and a control method thereof, and an LED control circuit. The present disclosure is applied in an LED control circuit of TRIAC dimming, directly or indirectly detects cross-zero point of input voltage; after cross-zero point of the input voltage is delayed by a second time, the bleeder module works to generate bleeder current, and a time between turn-on time of the TRIAC and a time that a driving circuit input current achieves a predetermined value (maintaining current of TRIAC) is a first time. During the first time, the bleeder circuit generates losses; when the first time is greater than a predetermined value, the second time is prolonged; when the first time is smaller than the predetermined value, the second time is reduced, such that the first time is close to or equal to the predetermined value. By using the present disclosure, the second time, which is used as the delay time, is self-adaptively adjusted according to the first time and the predetermined value, and the bleeder power consumption is reduced and system efficiency is enhanced.