660 results about "DIAC" patented technology

The invention discloses an LED drive circuit with dimming function and a lamp. The LED drive circuit comprises a TRIAC dimmer; the TRIAC dimmer receives an alternating-current input voltage and generates a cut phase voltage signal; the cut phase voltage signal is rectified by a rectifying module and then coupled to a dimming signal generator; and a power factor correcting controller receives an output signal of the dimming signal generator, reflects a feedback signal of LED brightness, and outputs a switching control signal to control the on and off of a switching tube so as to drive an LED. The dimming of the LED is implemented by adjusting a conduction angle of the TRIAC dimmer.

A quasi-phase active preload circuit to be coupled at the output of a non-isolated LED driver converter having a pre-stage phase-angle control dimmer circuit, such as a commonly used leading-edge control Triac dimmer, is disclosed. The quasi-phase active preload circuit may include a preload resistor coupled to a current-controlled current source configured to draw a sinking current through the preload resistor based on a peak detect signal. The peak detect signal may be, in one example, representative of a leading-edge peak voltage of an output of the Triac dimmer circuit, which may be representative of a conduction angle of the Triac dimmer circuit. During normal operating conditions, no sinking current is drawn through the preload resistor. During low dimming conditions, a sinking current that is responsive to the peak detect signal is drawn through the preload resistor. During deep dimming or when used with a leaky Triac dimmer, a maximum sinking current may be drawn through the preload resistor by the current-controlled current source.

The invention relates to a voltage-stabilization electricity-saving device, and particularly relates to an undisturbed switching mechanism of the voltage-stabilization electricity-saving device. The undisturbed switching mechanism comprises a power source, a compensation transformer connected with the power source and a voltage-regulating transformer connected in series between the power source and the compensation transformer. The undisturbed switching mechanism further comprises a load connected in parallel at the two ends of the compensation transformer, and a bidirectional thyristor mechanism connected in series with the compensation transformer. The undisturbed switching mechanism is characterized in that the undisturbed switching mechanism further comprises a series circuit formed by a resistor and a bidirectional thyristor, wherein the series circuit is connected in parallel to the secondary coil of the compensation transformer. Compared with the prior art, the undisturbed switching mechanism in the invention solves the problem of strong impact generated during thyristor switching, and obvious noise cannot be generated during switching, so that the stability of the system is greatly improved, the service life of the thyristor is prolonged, and the capacity of the intelligent voltage-stabilization electricity-saving device can be greatly increased when the thyristors with same capacity and withstand voltage level are adopted.

A two terminal arc suppressor for protecting switch, relay or contactor contacts and the like comprises a two terminal module adapted to be attached in parallel with the contacts to be protected and including a circuit for deriving an operating voltage upon the transitioning of the switch, relay or contactor contacts from a closed to an open disposition, the power being rectified and the resulting DC signal used to trigger a power triac switch via an optoisolator circuit whereby arc suppression pulses are generated for short predetermined intervals only at a transition of the mechanical switch, relay or contactor contacts from an closed to an open transition and, again, at an open to a close transition during contact bounce conditions.

A light-adjusting and current-limiting control circuit for a lamp includes a sampling circuit formed of a manganese-copper line or a current transformer, a power circuit provided with resistors, capacitors, diodes, a Varistor and a zener diode, a signal adjusting circuit composed of diodes, resistors, a varistor, triacs and capacitors, and a control output circuit having a thyristor, diodes, a relay and an LED. The control output circuit can be replaced with a light-adjusting input circuit, a chip processor control circuit, a zero-crossing detection circuit and a two-way silicon controlled rectifier control output circuit 5. Thus, the invention has a low cost, a small size and an excellent precision, compared to conventional ones.

Disclosed herein is a dimmer switch having a broad range of control with a relatively simple circuit having a number of safety features. The circuit employs a triac and diac to selectively conduct an AC power wave. A variable phase shift network having an improved range of control governs the firing angle of the diac. The variable phase shift network includes a first and second series R-C circuits coupled by a bridge resistor.

An electromagnetic interference (EMI) filter is provided to attenuate potentially damaging high frequency electromagnetic interference from interfering with the operation of a hermetically sealed implantable medical device. In one embodiment, the EMI filter is joined to a bypass unit that is configured to provide an energy path for the delivery of an energy pulse. The bypass unit, in one embodiment, may include a non-linear device in parallel with an impedance component. The non-linear device can be a DIAC, a MOSFET, or any other non-linear semiconductor array. The EMI filter may be located within the header assembly, the feedthrough assembly, or located proximate to a pulse generator along the energy delivery path.

A triac controller includes a triac driver that provides a triac control signal suitable for connection to a gate terminal of a triac, such that, when in a power-on condition, the control signal carries at least a first firing pulse during each half period of the alternating current power supply. A soft start subcircuit and a zero crossing detector directs the triac driver to produce the first firing pulse at a first firing pulse delay time after the zero crossing time. During a soft start operation the first firing pulse delay time varies monotonically with each successive half period from an initial delay time to a final delay time. An auto-retriggering subcircuit causes the triac driver to produce a second firing pulse at a predetermined retriggering delay time from an end of the first firing pulse if the triac is not in an on conduction state after the end of the first firing pulse during a same half period. The auto-retriggering subcircuit causes the triac driver to produce retriggering firing pulses periodically for so long as the triac is not in the on conduction state during the same half period; however, it is inhibited from causing the triac driver to produce retriggering firing pulses during a predetermined retriggering mask period at an end of the same half period. The soft start subcircuit includes a table specifying a plurality of predetermined first firing pulse delay values. A set signal is used to determine an index into the table. The plurality of predetermined first firing delay values is monotonically organized with respect to the index into the table, and a programmable rate variable determines a rate of change of the first firing delay values during a soft start operation.

The invention discloses a bidirectional triode thyristor for electrostatic discharge protection of a radio frequency integrated circuit, comprising a P-type substrate on which a P trap, a first N trap and a second N trap are arranged, wherein the first N trap and the second N trap are arranged at two sides of the P trap; a first N<+> injection region, a first P<+> injection region and a third N<+> injection region which are isolated by a shallow ditch are sequentially arranged above the first N trap from the outside to the inside, wherein the third N<+> injection region crosses the junction of the first N trap and the P trap; a second N<+> injection region, a second P<+> injection region and a fourth N<+> injection region which are isolated by a shallow ditch are sequentially arranged above the second N trap from the outside to the inside, wherein the fourth N<+> injection region crosses the junction of the second N trap and the P trap; and the surface of the P trap arranged between the third N<+> injection region and the fourth N<+> injection region is covered with gate oxide and polysilicon gates which are stacked in sequence from bottom to top. By utilizing the source-drain punchthrough of an NMOS (N-Channel Metal Oxide Semiconductor) to assist in triggering, the bidirectional triode thyristor provided by the invention has small starting voltage and parasitic capacitance and strong robustness and can provide bidirectional ESD (Electro-Static Discharge) protection.

The invention relates to a method and a device for fluorescent lamp two-wire system dimming control. A user end microprocessor receives a user request signal to ensure that the change in a circuit is impeded, thereby a large chamfer voltage waveform signal is formed on an alternating wire within a period of time and forms a dimming control signal after being subjected to waveform conversion of an electronic ballast and signal detection processing. The device is formed by connecting a user control end and an electronic ballast end through alternating current wires. The user control end comprises a dimming control signal input circuit, an impedance switching circuit and a bidirectional control silicon circuit; and the electronic ballast end comprises a rectifying circuit, a power factor correction circuit and an inverter circuit which are sequentially connected, and a waveform conversion circuit, a waveform recognition and digital/analogue conversion circuit and a lower-pass filter circuit. The invention forms the large chamfer voltage waveform signal only in short time for regulation and control operation and only maintains a smaller initial chamfer in other time, therefore, the power factor of the ballast can be maintained above 0.95 and the total current harmonic distortion can be improved to be less than 20 percent.

The invention discloses a self-adaptive PID (proportion integration differentiation) temperature control method, which comprises the following steps of: step 1, collecting a temperature in real time; step 2, calculating a heating speed in real time; step 3, adjusting a PID parameter according to the real-time heating speed; step 4, carrying out PID arithmetic; and step 5, converting the result of the PID arithmetic into continuous control on a time quantum, and directly controlling the switching on and the switching off of the working current of a heater strip by using a bidirectional silicon controlled rectifier. The technical effects of the self-adaptive PID temperature control method lie in that the heating speed is calculated in a heating process; a control parameter is adjusted dynamically, so that the heating process is more stable; the algorithm is subjected to multiple tests on a plurality of different instruments at different ambient temperatures; results show that an appointed temperature can be stably achieved in a heating way; an overshoot phenomenon cannot appear in the heating process; and the precision meets a system requirement.

An apparatus including an electrostatic discharge (ESD) protection structure with a diac in which substancially similar ESD protection is provided for both positive and negative ESD voltages appearing at the circuit electrode sought to be protected.

A protected capacitor system/method implementing enhanced transient over-voltage suppression is disclosed. The system/method incorporates one or more surge suppression devices (SSDs) proximally located and in parallel with a capacitor structure to produce an overall protected capacitor structure having enhanced reliability and simultaneous ability to resist transient overvoltage conditions. The SSDs are formed from series combinations of transient voltage surge suppressors (TVSs) (metal oxide varistor (MOV), diode for alternating current (DIAC), and/or silicon diode for alternating current (SIDAC)) and corresponding shunt diode rectifiers (SDRs) and placed in parallel across a capacitor structure to locally suppress voltage transients across the capacitor structure in excess of the voltage rating of the capacitor structure. The parallel shunting TVB/SDR pairs may be integrated into a printed circuit board (PCB) assembly that is externally attached to the capacitor structure or encapsulated in an enclosure incorporating the capacitor structure.

The present invention relates to a contactless enegy-saving starter which is characterized in that: the device includes a PTC thermosensitive resistor Rp, a three-end bidirectional controllable silicon T, a photocoupler U, a sensor L and a rectifying bridge D. In the present invention, a photocoupler U is used to trigger the three-end bidirectional controllable silicon T, thus, the situation that the controllable silicon is not conducted and stopped absolutely because of the un-synchrony of the phase of the triggered control signal and the started loop is avoided, and the reliability is improved greatly. Thus, not only the successful stating of the electric motor is assured, and the started loop is broke absolutely because the bidirectional controllable silicon is stopped absolutely after the starting is achieved. The energy consumption by the thermosensitive resistor Rp is eliminated because there is no current flowing through the PTC thermosensitive resistor Rp.

A tunable voltage isolation ground to ground ESD clamp is provided. The clamp includes a dual-direction silicon controlled rectifier (SCR) and trigger elements. The SCR is coupled between first and second grounds. The trigger elements are also coupled between the first and second grounds. Moreover, the trigger elements are configured to provide a trigger current to the dual-direction silicon controlled rectifier when a desired voltage between the first and second grounds is reached.

The invention provides a control circuit and method for a discharge circuit, a chip and a driving system and method. The control method comprises the steps of controlling the delay conduction time ofthe discharge circuit in the next period according to the obtained current period light modulator conduction time, the expected conduction time and the preset time different threshold, and generatingan enable signal used for dynamically adjusting the discharge circuit according to the delay conduction time. By controlling the enable signal of the discharge circuit, a bidirectional silicon controlled rectifier of the light modulator is enabled to trigger the conduction by being delayed to the expected conduction time, so that the power consumption of the discharge circuit is reduced, and the reliability of a driving system of the light modulator is improved.