281 results about "Opto-isolator" patented technology

A power converter employing a control system configured to make multiple functional use of a circuit node therein and method of operating the same. In one embodiment, the power converter includes a power train including at least one power switch. The power converter also includes a control system including an opto-isolator circuit, including a resistor, configured to receive an output signal from the power converter and provide a feedback signal to a feedback node for the control system to provide a switch control signal for the at least one power switch. The control system also includes a current source configured to produce multiple voltage levels at the feedback node in accordance with the resistor, thereby enabling multiple functional uses of the feedback node.

A power converter with reduced power dissipation at light loads and method of operating the same. In one embodiment, the power converter includes an opto-isolator circuit configured to produce an output signal dependent on an output characteristic of the power converter. The power converter also includes a controller configured to control the output characteristic to a first regulated value when the output signal is greater than or equal to a threshold level, and control the output characteristic to a second regulated value less than the first regulated value when the output signal is less than the threshold level.

A zone selective interlocking system for electronic trip circuit breakers includes a plurality of downstream terminals, each downstream terminal connecting with at least one of a plurality of downstream electronic trip circuit breakers having input terminals. A restraint input circuit module, including a voltage comparator, is connected to the input terminals of each of the downstream electronic trip circuit breakers and the input terminals are shorted together providing a self-restraint signal for each downstream electronic trip circuit breaker at the occurrence of a downstream fault condition. The system also includes a plurality of upstream terminals, each upstream terminal connecting with at least one of a plurality of upstream electronic trip circuit breakers having input terminals. The restraint input circuit module is connected to the input terminals of each of the upstream electronic trip circuit breakers for receiving a signal indicative of the downstream fault condition and wherein the restraint input circuit module is self-sourcing. An output circuit module including an opto-isolator is connected to each of the upstream electronic trip circuit breakers and each of the downstream electronic trip circuit breakers for providing galvanic isolation between circuit breakers in a restrained mode and circuit breakers in an unrestrained mode.

The invention discloses a distributed sensing system based on a weak Bragg reflection structure. The distributed sensing system comprises a SG-DBR (Screen Grid-Distributed Bragg Reflector) tunable laser (1), an electrooptic modulator (4), an opto-isolator (5), an optical circulator (6), and weak Bragg reflection cycle structural optical fibers (7), which are connected in turn; wherein the SG-DBR tunable laser (1) is controlled by a wavelength tuning control circuit (2), the electrooptic modulator (4) is controlled by an impulse function generator (3), a photo-detector (8) is connected with the optical circulator (6), control signals outputted by the wavelength tuning control circuit (2) and the electrooptic modulator (4) and electric signals outputted by the photo-detector (8) enter a data acquisition card (9) jointly, and are processed and then transmitted to a data processing device (10). The distributed sensing system realizes the long-distance distributed sensing alarm for parameters such as temperature, stress and vibration, and has the characteristics of higher detection sensitivity and positioning precision, easiness for realization, lower cost and reliability for operation.

The invention discloses a high bandwidth tunable double-passband microwave photon filter, belongs to the field of microwave photonics, and relates to the high bandwidth tunable double-passband microwave photon filter based on high non-linear optical fiber excited brillouin scattering effects and multiple pumping signals. The filter consists of a first laser, a first phase modulator, an opto-isolator, a vector network analyzer, a high non-linear optical fiber, a second laser, a strength modulator, a microwave signal source, a second phase regulator, a pulse code generator, an erbium-doped optical fiber amplifier, an optical circulator and a photoelectric detector. The filter is based on phase modulation and excited brillouin scattering effects caused by two pumping signals, and thus double-passband output of the microwave photon filter is achieved. By changing the frequency of the two pumping signals, the frequency of two passband centers can be randomly modulated within a certain frequency range. Through binary phase shift keying modulation on the pumping signals, the bandwidth of the pumping signals can be changed, and thus adjustment on the output bandwidth of the filter is achieved.

The invention provides a high non-linear optical fiber excited Brillouin scattering effect and amplitude ratio based microwave frequency measurement method and device and belongs to the technical field of microwave photonics. The device provided by the invention is composed of a tunable laser, a coupler, a phase modulator, a strength modulator, a vector network analyzer, an opto-isolator, a high non-linear optical fiber, a circulator, an erbium-doped optical fiber amplifier, a microwave signal source, a DC voltage stabilizing power source and a photoelectric detector. The frequency range of to-be-detected microwave signals can be enlarged through increasing bandwidths of the strength modulator and the phase modulator and enlarging the scanning range of the vector network analyzer and measurement precision can be improved through reducing noise in optical links and increasing the magnitude of energy transfer of excited Brillouin scattering effect. According to the invention, an amplitude ratio function curve is constructed based on the high non-linear optical fiber excited Brillouin scattering effect and a frequency value of to-be-detected microwave signals is obtained through the amplitude ratio function curve. Therefore, the measurement precision is improved.

A short circuit detector for a fieldbus network which includes power / data wires that are typically positive and negative, respectively, and a shield conductor connected to a ground includes first and second high-impedance semiconductor circuits coupled between each of the leads and the shield conductors. Both circuits may either have a dedicated alarm indicator which indicates the presence of a short circuit between that conductor and the shield and / or may be coupled together to an alarm circuit which activates an alarm whenever a short circuit exists between either of the power / data leads and the shield conductor. The alarm circuit may have a ground which is isolated from the shield ground and may thus employ an isolation device such as an opto-isolator.

A circuit and method is disclosed for measuring the resistance of a resistive sensor, such as a PTC or NTC temperature sensor used for monitoring the temperature of the windings of an electric motor. The measurement circuit is based on an electronic circuit in which conductors from a sensor located in the object to be monitored are connected to an amplifier circuit in a feedback configuration that reduces the DC level supplied to the voltage divider when the sensor resistance increases. The measured signal is amplified and, using a comparator to compare it with the output voltage of a sawtooth generator, a continuous PWM (Pulse Width Modulation) signal is generated and transmitted in digital format to a SELV electronic circuit, for example through an opto-isolator. The essentially logarithmic signal amplification makes it possible to reliably distinguish between a short circuit in the sensor circuit and low values of sensor resistance.

A fly-back AC-DC power converter has a constant-current control loop that senses the primary output current in a transformer to control the secondary output without an expensive opto-isolator. A primary-side control circuit can use either a Quasi-Resonant (QR) or a Pulse-Width-Modulation (PWM) control loop to switch primary current through the transformer on and off. A feedback voltage is compared to a primary-side voltage sensed from the primary current loop to turn the switch on and off. A multiplier loop generates the feedback voltage using a multiplier. A level-shift inverter and a low-pass filter act as the multiplier by multiplying an off duty cycle of the switch by the feedback voltage to generate a filtered voltage. A high-gain error amp compares the filtered voltage to a reference voltage to generate the feedback voltage. The multiplier produces a simple relationship between the secondary current and the reference voltage, yielding simplified current control.

An all-optical true random number generator with a Tbps code rate comprises an all-optical true random number entropy source and an all-optical quantizer, wherein the all-optical true random number entropy source adopts an rational harmonic mode-locked Er-doped fiber ring laser, actually a ring-shaped cavity formed by a lithium niobate electro-optic modulator, an optical band pass filter I, an erbium-doped fiber amplifier, an opto-isolator and an optical coupler which are connected through fiber; and the all-optical quantizer is a quantum dot quarter wave phase-shift distributed feedback type laser. The generator provided by the invention solves the problems that the code rate is too low and untunable in the prior art, has a Tbps-level code rate, is in direct compatible with an optical network, and meets the safety requirements of modern high-speed secure communication.

Light emitters using nanotubes and methods of making same. A light emitter includes a nanotube article in electrical communication with a first and a second contact, a substrate having a predefined region with a relatively low thermal conductivity said region in predefined physical relation to said nanotube article; and a stimulus circuit in electrical communication with the first and second contacts. The stimulus circuit provides electrical stimulation sufficient to induce light emission from the nanotube article in the proximity of the predefined region. The predefined region is a channel formed in the substrate or a region of material with relatively low thermal conductivity. The light emitter can be integrated with semiconductor circuits including CMOS circuits. The light emitter can be integrated into optical driver circuits (on- and off-chip drivers) and opto-isolators.

An interface circuit for a lamp ballast includes first and second input power lines, L1 and L2, with first and second respective switches, and a neutral power line N, all coupled to a diode bridge. Closing one of the first or second input power lines L1 or L2 causes a photodiode in an opto-isolator coupled to the diode bridge to turn ON, which in turn causes a MOSFET in a control circuit to be in an open state. When in the open state, a first resistor coupled to the source of the MOSFET is included in the control circuit and causes a lamp attached thereto to operate in a dimmed state. When both input power line switches are closed, L1 and L2 are both coupled to the diode bridge and thereby cause the phototransistor to be in an OFF state, which causes the MOSFET to close, thereby including a second resistor, coupled to the drain of the MOSFET, in the control circuit in parallel with the first resistor. This in turn causes the lamp to operate at full intensity.

An optical amplifier of the invention comprises first and second optical amplification sections connected in a cascade manner between an input terminal and an output terminal. Optical isolators which block C-band ASE travelling in an opposite direction to L-band signal light, are inserted on the amplification medium of each of the optical amplification sections. A constant gain control section calculates the number of wavelengths based on the input power of signal light, and controls the pumping light power of each optical amplification section at a constant slope with respect to the number of wavelengths, so that the respective gains in the optical amplification sections corresponding to the number of wavelengths each become constant. As a result, it is possible to maintain flat gain wavelength characteristics even when receiving input of WDM light where the number of wavelengths varies rapidly over a wide range.

An apparatus for monitoring battery voltage and temperature includes a host controller and acquisition boards, and every acquisition board for the battery includes a voltage acquisition module, a temperature acquisition module, a host control chip MCU, A / D convertor module, an opto-isolator module, a CAN bus communication module and two external connection ports CN1, CN2. The input end of the AD transformation module is connected with the output end of the voltage acquisition module and the temperature acquisition module, and the output end of the A / D convertor module is connected with the opto-isolator module via a SPI bus, and the I / O port of the SPI bus module in the main control chip MCU is connected with the opto-couple isolation module, and the host control chip MCU is connected with the CAN bus communication module of the host controller via the CAN bus communication module, and the acquisition boards are connected via a socket piece in turn. The present invention is simple in structure, convenient in operation, high in data precision and high in the consistency and interchangeability of each acquisition board. Furthermore, the present invention utilizes opto-isolator module to isolate the high-voltage battery with the host controller circuit, so as to avoid the problem of common mode interference.

The invention relates to an active detecting type fiber grating cable tunnel security and protection monitoring system. The active detecting type fiber grating cable tunnel security and protection monitoring system consists of a pump light source, a first coupler, a hydrophone, a low-frequency vibration sensor, an opto-isolator, a second coupler, a non-equilibrium Mach-Zehnder interferometer, a wavelength selector, a photoelectric detector, a piezoelectric transducer (PZT) driver, a digital acquisition device, a program gain control (PGC) phase demodulator and a computer provided with an alarm information managing platform. The active detecting type fiber grating cable tunnel security and protection monitoring system has the advantages of adopting a fiber grating sensor technology, being anti-electromagnetic-interference, electrically insulating, corrosion-resisting, good in safety, long in service life and easy to network, achieving remote distributed measurement and the like, has high sensitivity of an interference type demodulating system, can monitor sound inside and outside a cable tunnel and vibration produced by invaded people, reduces false alarm rate, improves identification on alarm events and operation safety supervision level of a power system and provides a safe and effective management mode for a power transmission system.

A visible light strengthened super continuous spectrum laser system with an all-optical-fiber structure comprises an optical fiber mode-locked laser, a single mode fiber amplifier, an opto-isolator, a double cladding fiber amplifier, a nonlinear photonic crystal fiber. The single mode fiber amplifier is connected with the output of the optical fiber mode-locked laser through an optical fiber; the opto-isolator is connected with the output of the single mode fiber amplifier through the optical fiber; the double cladding fiber amplifier is connected with the output of the opto-isolator through the optical fiber; and an output end of the double cladding fiber amplifier is connected with an input end of the nonlinear photonic crystal fiber through a pulling optical fiber. The system of the invention solves the technical problems that the high-power laser coupling device of the background art has huge volume, low coupling efficiency and limited spectral region. The system has the advantages of simple structure, small volume, high coupling efficiency, reliable engineering, capability of covering the visible light wave band and the like.

The invention discloses a system and a method for monitoring side-mode suppression ratio and channel stability of a tunable laser and relates to the device and the method for monitoring the dominant frequency and side-mode power of the laser through a sampling etalon to judge spectral quality and channel stability of the laser so as to carry out effective control. The monitoring system disclosed by the invention mainly comprises the tunable laser composed of a gain medium, a coupling optical part, a fixed lattice filter, a tunable filter and a reflective optical part, a beam collimation lens, an opto-isolator, a beam splitter component, an F-P (fabry-Perot) etalon, an optical detector, a coupling output lens, a controller, etc. Through a plurality filters outside a laser cavity and a photoelectric detection structure, wavelength lock is carried out; the spectral quality is evaluated; the tunable filter is timely adjusted and controlled; the lasing wavelength is stabilized in the required channel all the time, and good enough spectral quality is achieved. The monitoring system is suitable for online spectral quality monitoring in work of the laser and possible drift correction resulting from switching of the filter inside the cavity.

An automated AC line filter and surge suppression apparatus 100 having an inductive current sense loop (ICSL) circuit 10 for sensing inductive current at a load and controlling the application of AC line filter 112 to an AC power line to the load. Current sensor 12 in series with the input line senses inductive load current. A first bridge rectifier 14 rectifies the sensed load current to a proportionate DC voltage, which triggers a switch 24. The output of switch 24 is fed into an opto-isolator 26, which in turn controls second switch 28. Switch 28 connects or disconnects AC line filter 112 from the system according to a predetermined sensed inductive current at the load. MOVs 102 and capacitive elements 104 provide continuous surge suppression protection to the load.

The invention discloses a laser marking galvanometer scanning system based on machine vision. The laser marking galvanometer scanning system comprises an image processing system, a laser galvanometer scanning system and a motion control system and specifically comprises a light source, a camera lens, a CCD (Charge Coupled Device) camera, an image capture card, an image processing software, a fiber laser, an opto-isolator, a laser beam-expanding lens, an XY scanning galvanometer, an F-theta lens, a monitor, a communication / input output unit and a three-dimensional adjusting bracket. The laser marking galvanometer scanning system utilizes the machine vision to acquire the position of the workpiece from the view field of the camera, to finish the information capture and the signal conversion and to perform coordinate conversion and direction conversion on the marking document, so that the marking position on the subsequent workpiece is consistent with the position of the first workpiece. Meanwhile, the marking depth can be online measured and the information is supplied for the online feedback control on the laser marking. Compared with the traditional marking positioning, the laser marking galvanometer scanning system has the advantages that different fixtures need not be prepared for different workpieces, the purpose of positioning the workpiece is achieved by only training the machine vision for identifying different patterns, the real-time online detection for the marking quality is performed, the cost is lowered, the general automation is easily realized and the processing precision is further increased and ensured.

The invention discloses a laser line width measuring system and method based on an electro-optic modulator and an adjustable radio source. The system comprises a to-be-measured laser, an opto-isolator, a 2*2 optical fiber coupler, an integrated photoelectric detector, a spectrum analyzer and a frequency shift fiber ring. The frequency shift fiber ring is connected between an output port D and an input port C of the 2*2 optical fiber coupler and at least comprises a frequency shifting device and an optical fiber delay line, wherein the frequency shifting device is composed of the electro-optic modulator and the adjustable radio source. The adjustable radio source is used for providing radio driving signals with the adjustable frequency shifting amount for the electro-optic modulator, and the frequency shifting amount can be adjusted in real time by controlling the modulation frequency injected into the electro-optic modulator by the adjustable radio source. The frequency shifting amount can be increased, the adjustable band width range is enlarged to 10 GHz, and the line width measurement limit reaches 1 Hz.

A two-port isolator includes a microwave ferrite member, first and second center electrodes that intersect with each other on the ferrite member with isolation therebetween, a permanent magnet that applies a DC magnetic field to the ferrite member, and a multilayer substrate having center-electrode-connecting electrodes and first and second matching capacitors. The ferrite member, the first and second center electrodes, the permanent magnet, and the multilayer substrate are accommodated in a housing that includes a magnetic cap and a case having a magnetic metal plate molded thereonto. The second matching capacitor has a higher Q factor than the first matching capacitor.

An optical connector includes a printed circuit board (PCB), an optical-electric coupling element, and a jumper detachably attached to the optical-electric coupling element. The optical-electric coupling element is positioned on the PCB. The optical-electric coupling element includes at least two first coupling lenses and a sloped surface. The optical-electric coupling element defines a stepped receiving cavity in its sidewall. A bottom surface of the stepped receiving cavity forms at least two second coupling lenses. The jumper is detachably inserted into the stepped receiving cavity, and the jumper has at least two receiving holes receiving at least two optical fibers. Each optical fiber is optically aligned with a respective second coupling lens. Each second coupling lens is optically aligned with a respective first coupling lens via the sloped surface.

A circuit and method is disclosed for measuring the resistance of a resistive sensor, such as a PTC or NTC temperature sensor used for monitoring the temperature of the windings of an electric motor. The measurement circuit is based on an electronic circuit in which conductors from a sensor located in the object to be monitored are connected to an amplifier circuit in a feedback configuration that reduces the DC level supplied to the voltage divider when the sensor resistance increases. The measured signal is amplified and, using a comparator to compare it with the output voltage of a sawtooth generator, a continuous PWM (Pulse Width Modulation) signal is generated and transmitted in digital format to a SELV electronic circuit, for example through an opto-isolator. The essentially logarithmic signal amplification makes it possible to reliably distinguish between a short circuit in the sensor circuit and low values of sensor resistance.

A home automation module having an externally powered communications port. The module includes an automation microprocessor for controlling the module, a communications port for enabling the module to draw power in limited quantities from an external source, a receiver / transmitter section, a power line carrier (PLC) coupler for enabling the transfer of signals between the module and a main while electrically isolating the module from the main, a zero-crossing detector for monitoring the phase of the power on the main while maintaining substantial electrical isolation of the module from the main, and a boost regulator for enabling the module to derive sufficient power from the communications port to drive the PLC coupler during signal transmissions from the module to the main. The detector maintains substantial electrical isolation through an opto-isolator. The boost regulator stores up power over time so that sufficient power will be available when the demand is made.

A fan motor speed control system for controlling the fan motor speed of an air conditioning system includes a power output circuit including a power triac which is turned on and off by an opto-isolator connected to a pulse generator circuit for varying an AC voltage waveform imposed on the fan motor. The pulse generator circuit is connected to heating and cooling ramp circuits and a minimum speed circuit to provide a variable voltage signal imposed on the pulse generator circuit corresponding to the temperature difference sensed by a return air sensor and a heating or cooling sensor or by separate heating and cooling sensors disposed adjacent respective heating and cooling heat exchangers of the air conditioning system. An adjustable minimum speed circuit and a cutoff circuit are provided to control motor minimum speed or motor shutoff when a predetermined minimum speed is reached to prevent motor bearing failure or overheating. Sensor protection circuits in the control system operate to drive the motor to full speed if any of the temperature sensors experience an open or short circuit condition. The control system circuit maximizes air conditioning system efficiency by capturing additional heating or cooling effect, reduces noise associated with motor startup and shutdown, and reduces rapid change in the sensed temperature in the air conditioned space during motor startup and shutdown.

The invention provides a correlation sampling based laser multi-pulse ranging system, relating to a laser ranging system. The correlation sampling based laser multi-pulse ranging system is provided with a clock control circuit module, a laser pulse transmitting module, a laser pulse receiving module and a time information processing module, wherein the clock control circuit module is provided with two clock signal output ends and is provided with a local oscillator, a first frequency divider, a second frequency divider, a first mono-stability trigger and a second mono-stability trigger; the laser pulse transmitting module is provided with a pulse driving circuit, a semiconductor laser, an opto-isolator and a collimating lens; the laser pulse receiving module is provided with an avalanche photodiode, a pre-filtering amplifying circuit, an opto-isolator and a focusing lens; and the time information processing module is provided with a first sample holding circuit and a second sample holding circuit. A sampling signal is subjected to frequency doubling, the sampling time of transmitting pulse and receiving pulse is reduced, the ranging speed is increased, the measurement precision is improved, and the correlation sampling based laser multi-pulse ranging system can solve the problem of low precision in a short-range laser ranging mode.