38results about How to "Increase time constant" patented technology

The invention discloses a double-phase-locked loop circuit and a control method thereof. The double-phase-locked loop circuit comprises a phase / frequency detector, a charge pump, a frequency adjustment circuit and an N frequency divider. The frequency adjustment circuit comprises a coarse adjustment circuit, a fine adjustment circuit and a current-controlled oscillator, wherein the coarse adjustment circuit is used for coarse adjustment of frequency of output signals of phase-locked loops till approaching a target frequency; the fine adjustment circuit is used for fine adjustment of the frequency of the output signals of the phase-locked loops till the target frequency; and the current-controlled oscillator is coupled with the coarse adjustment circuit and the fine adjustment circuit and used for producing the output signals of the phase-locked loops, wherein the frequency of the output signals is the target frequency. The double-phase-locked loop circuit can effectively achieve the purpose of expanding the frequency adjustment range under the situation of keeping the loop bandwidth of the phase-locked loops smaller, realize the on-chip integration and further reduce the cost and the design complexity of the circuit.

The invention belongs to the technical field of radio frequency identification, and particularly relates to a rectifying and amplitude limiting circuit with multiple time constants, and a passive radio frequency tag containing the rectifying and amplitude limiting circuit. By applying different time constants on the control ends of two discharging paths of the rectifying and amplitude limiting circuit, namely that the analog control signals with adjusted voltage amplitude can be carried out at different switching speeds, so the switching between complete opening and complete closing of the two discharging paths is realized; the applicable discharging is carried out according to the size of charge amount at the antenna end and the energy level of the tag, so the demodulation level of the tag is improved, and the reading and writing distance of the tag is improved.

The invention provides a fully differential switch capacitor integrator. The fully differential switch capacitor integrator comprises an operational amplifier unit, a switch capacitor unit, a switch capacitor common-mode feedback unit, and a non-overlapping clock production unit, wherein the operational amplifier unit comprises an operational amplifier for providing predetermined gain and bandwidth; the switch capacitor unit comprises a switch capacitor integral unit bridged between the input end and output end of the operational amplifier, a serial branch comprising a MOS switch phi2 and a capacitor C1, wherein the capacitor C3 is connected with the above branch in parallel, and a MOS switch phi1 is further arranged between the MOS tube phi2 and the capacitor C1 to connect to a referencevoltage Vref, and partial positive feedback capacitor C2 connected to the output end of the opposite polarity of the operational amplifier; the switch capacitor common-mode feedback unit is arranged between the positive output end and the negative output end of the operational amplifier, and is a six-switch four-capacitor structure; the non-overlapping clock production unit produces a clock signalof the MOS switch. The fully differential switch capacitor integrator provided by the invention is insensitive to parasitic, and has efficient area utilization rate and greater time constant.

The invention discloses a drive circuit, display panels and a display device. The drive circuit comprises a drive circuit board; a plurality of gate drive chips which are connected with the drive circuit board; a connection line for connection of the drive circuit board and the gate drive chips; fanout lines connected between the gate drive chips and gate lines of the display panel, wherein the fanout lines connected with the same gate drive chip form a fanout area, and the fanout areas are arranged along a transmission direction of signals; and additional conductive film set in the fanout areas, wherein an effective area of the additional conductive film set in each fanout area is different, and the effective areas are reduced one by one starting from the first fanout area. According to the drive circuit, the display panels and the display device, the additional conductive film is added to the fanout areas to form a compensation capacitor, thereby increasing a time constant of signaldelay of a previous fanout area, so the time constant of the signal delay of each fanout area is equal, and the signals of each fanout area are output synchronously.

The invention discloses equipment for determining the proportion of gas in a gas mixture, comprising a measuring chamber, an ultrasonic wave source and an ultrasonic wave detector and a temperature sensor. The measuring chamber is provided with a chamber limiting structure containing a high heat conduction material, a gas inlet and a gas outlet, wherein the material is metal; the ultrasonic wave source and the ultrasonic wave detector are mounted to enable the ultrasonic wave source to transmit the ultrasonic wave to the ultrasonic wave detector through the measuring chamber; and the temperature sensor is mounted to enable the sensor to sense the temperature in the measuring chamber, wherein the measuring chamber has a tubular cavity with a radius r0 of 1-8mm so as the make the distance between gas in the measuring chamber and an inner wall of a tube, and the measuring chamber is designed so as to make the gas to be measured to tightly contact a rigid surface of an object with thermal inertia and good heat conduction, thus the heat can free move to a surrounding structure from the gas.

The invention provides a controller, a chip and a method for eliminating current ripples of an LED (Light-Emitting Diode) driving system. The controller is electrically connected with an output end of an LED load and a first sampling resistor; the controller is configured to sample a voltage at an output end of the LED load and voltages at two ends of the first sampling resistor, and generate a first voltage signal according the voltage at the output end of the LED load and the voltages at the two ends of the first sampling resistors; the controller is used for generating a control signal according to the first voltage signal and voltages at the two ends of the first sampling resistor to control a conducting state of a power tube which is electrically connected with the LED load, so that the voltage magnitude of the first voltage signals is equal to that of a reference voltage, and the current ripples of the LED load are eliminated. Through adoption of the controller, the chip and the method, the LED current ripples are eliminated in a whole dimming process, and LED flickering caused by low-frequency jittering is avoided.

The invention is an amplifying circuit, containing an amplifier which has a positive input end, a negative end, a positive output end and a negative output end; a first input impedance connected between the negative input end and a first input signal; a second input impedance connected between the positive input end and the first input signal; a third input impedance connected between the negative input end and a second input signal; a fourth input impedance connected between the positive input end and the second input signal; a first output impedance connected between the negative input end and the positive output end; a second output impedance connected between the negative input end and the negative output end; a third output impedance connected between the positive input end and the positive output end; and a fourth output impedance connected between the positive input end and the negative output end.

The invention discloses a soft starting device, which comprises a current source, a first transistor and a second transistor; wherein the first transistor is coupled with the current source and decides the conducted current magnitude of the first transistor according to a voltage, and the second transistor is also coupled with the current source and decides the conducted current magnitude of the second transistor according to a fixed bias voltage; wherein an initial voltage value of the initial voltage is less than the voltage value of the fixed bias voltage, but after the soft starting, the voltage value of the first voltage increases gradually until larger than the voltage value of the fixed bias voltage, thus leading the soft starting to be implemented smoothly.

The invention provides a method for measuring gas cluster ion beam mass spectra. Cluster ions form a pulsed ion beam through an electrostatic capacitor, the pulsed ion beam is sprayed to a Faraday cupconnected to a field effect transistor (FET) source follower, and an oscilloscope is used to measure signals generated by cluster ions of different masse respectively in the pulsed ion beam, and TOFmass spectra of the cluster ions are obtained by TOF mass spectrometry. The invention also provides a device for measuring gas cluster ion beam mass spectra based on the measuring method. The device includes the Faraday cup for receiving the pulsed ion beam, the FET source follower connected with the Faraday cup and the oscilloscope. According to the method, by taking a field effect transistor asthe source follower and adopting the special design of directly connecting the field effect transistor with the Faraday cup, a time constant of a detector is reduced, so that detector response sensitivity is effectively improved, the mass spectrum resolution is improved, and the perfect ion beam mass spectra are obtained.

The invention belongs to the technical field of safety guarantee of extra-high-voltage alternating-current power grid electrical equipment, and particularly to a direct-current magnetic bias real-timecalculation method for extra-high voltage transformer parallel winding series resistance compensation. The method comprises the following steps: constructing three-dimensional geometric models of three transformers and a direct-current magnetic bias calculation magnetic field model according to actual structural parameters of a main transformer, a voltage regulation transformer and a compensationtransformer of the extra-high voltage transformer; calculating a self-inductance value when different currents flow through each transformer winding and a mutual inductance value between the windings; in combination with an electrical connection relationship among the three transformers, establishing an overall direct-current magnetic bias equivalent circuit calculation model of the three transformers through series resistance compensation voltage; solving the direct-current magnetic bias circuit model by using a fourth-order Runge-Kutta method of inductance parameters; multiplying the instantaneous current value of the branch where the series resistor is located by the increased series resistor to perform voltage compensation; and calculating the voltage and current values of each transformer and carrying out FFT (Fast Fourier Transform) to obtain the voltage and current harmonic condition of each transformer under the direct current magnetic bias of the extra-high voltage transformer.

In a structure including a voltage control circuit 1 for changing a voltage control signal 14 to control an oscillation amplitude of a transistor Q1 for oscillation, thereby stabilizing a voltage of a secondary output 13, there are provided a load suppressing circuit 5 for restricting a lower limit of a load impedance of a secondary coil L2 to prevent the oscillation of the transistor for oscillation from being stopped when the secondary output 13 is short-circuited, and an intermittent control circuit 2 for repeating an operation for reducing a voltage of the voltage control signal 14 to stop the oscillation when detecting a short circuit of a load and for raising the voltage of the voltage control signal 14 to restart the oscillation after stopping the oscillation.

The invention discloses a wideband GIS electronic voltage transformer device and a measurement method. The device comprises a built-in measurement electrode module, a conditioning module, a sampling module and a control module, wherein a measurement electrode of the built-in measurement electrode module is arranged in a GIS hand hole, and the measurement electrode penetrates through a GIS shell through a wire to be connected with a forward input end of a wideband amplifier of the conditioning module; a conditioning resistor and a conditioning capacitor of the conditioning module are connectedin parallel between a negative input end and a negative output end of the wideband amplifier; the sampling module performs analog sampling and analog-digital conversion to obtain a digital output voltage; and the control module calculates a GIS primary voltage value according to a voltage division ratio and the digital output voltage. Through the device and the method, electrode size miniaturization is realized, measurement bandwidth is expanded, transient characteristics are improved, the voltage transformation ratio is easy to regulate, and it is not needed to set secondary voltage division.

A flux pump with a high temperature superconductor belongs to the flux pump field and comprises an iron yoke, magnetic poles, a temperature connector, a heater, independent windings, electric current connectors and a high temperature superconductive thin piece. A row of magnetic poles are arranged on both the upper surface and the lower surface of the frame-shaped iron yoke; an independent winding is wound around each magnetic pole; the high temperature superconductive thin piece is arranged between two rows of magnetic poles; a sensor is arranged on the high temperature superconductive thin sheet; electric current connectors are connected to ends of the high temperature superconductive thin piece; the temperature connector is connected to the iron yoke; and the heater is arranged in the flux pump and used for heating the high temperature superconductive thin piece. The invention has the advantages that: the work capacity can satisfy a magnet system with the resistance of a superconductive closed loop being within 100microohm, the work ripple within 10<minus6> is realized, and the flux pump can be applied to the superconductive magnetic resonance imaging system as well as the superconductive magnet systems with higher requirements for the stability of the magnetic field, such as a magnetic resonance spectrometer, and the like.

The invention discloses a lower limit frequency expansion system for a non-contact measurement capacitive sensor. The lower limit frequency expansion system comprises an SMD capacitive sensor, a frequency band expansion device, a measurement cable, an RC compensation match circuit and a measuring system output port. The SMD capacitive sensor senses a voltage signal of a transformer coil wire turn according to the capacitive voltage division principle, and converts the high voltage signal into a low voltage signal. The frequency band expansion device increases the input impedance of a measuring system to expand the lower limit frequency of the capacitive sensor. The RC compensation match circuit can improve the high frequency characteristic of the measuring system. The capacitive sensor with the expanded lower limit frequency can be used for measuring power frequency voltage and long wave tail impulse voltage inside a coil.

The invention discloses a membrane sealed pistonphone, comprising a cavity, a piston and a support base for supporting the cavity. The piston and the cavity are coaxial. One end of the cavity is an opening end. The other end of the cavity is equipped with an end plate. A mounting hole is arranged on the end plate. The piston is located at the opening end of the cavity. Sealing membrane seals the opening of the cavity to form a sound production cavity. The sealing membrane is elastic. The sound production end face of the piston fits the sealing membrane. A pressure balancing hole is arranged on the cavity. The pressure balancing hole is communicated with the outside world and the sound production cavity. The pressure balancing hole is arranged on the end plate. A mounting hole is used for mounting a calibrated sensor. The membrane sealed pistonphone has the advantages that the cavity is sealed by the sealing membrane to form the sound production cavity; the cavity is communicated with the air of the outside world only through the set pressure balancing hole; a static pressure balancing mechanism is realized; the aperture of the pressure balancing hole is very thin, so the sound production cavity has a relatively large time constant; and the lower limit working frequency of the pistonphone is greatly reduced.

The invention provides a permanent magnet synchronous motor traction system. During the application process in the rail transit field, when IGBT pulses need to be blocked and an inverter unit needs tobe powered off and enter idle running, a first three-phase contactor and a second three-phase contactor in a system reput-into-service unit are disconnected. When reput-into-service is required, thefirst three-phase contactor can be directly put into service if a permanent magnet synchronous motor is running at low speed, the reput-into-service is carried out, the second three-phase contactor does not operate, and a disconnecting state is maintained; and if the permanent magnet synchronous motor is running at a high speed, the second three-phase contactor can be directly put into service, amotor stator performs current limiting and voltage division by means of resistors serially connected with phases of the second three-phase contactor, or slow down the current rise rate by means of inductors serially connected with phases of the second three-phase contactor, and increases circuit time constant, thereby suppressing overcurrent or overvoltage faults caused by too fast rise of motor stator current and DC side bus voltage at the reput-into-service moment.

The invention discloses a trap filter which comprises a first integrating circuit, a unit gain anti-phase circuit and a second integrating circuit. An input terminal of the first integrating circuit is an input terminal of the trap filter, an output terminal of the second integrating circuit is an output terminal of the trap filter, a feedforward capacitor connects the input terminal with a feedback input terminal of the second integrating circuit, a feedback resistor and a feedback capacitor are in parallel connection between the output terminal and a feedback input terminal of the first integrating circuit, and a current control circuit connects the first integrating circuit with an anti-phase input terminal of an operational amplifier in the second integrating circuit. The invention also discloses a low pass filter, wherein an integrating circuit has a same structure of the above trap filter. An integrator has a large time constant, using a large resistor and a large capacitor can be avoided, and integration becomes simple.

The present invention relates to a humidifier (10) for use in a test chamber, a test chamber, particularly a climatic chamber, etc., and a method for conditioning air in a test space of a test chamber. The humidifier comprises a container (11) having a container interior (12) for receiving a water bath (13), a heating device (15) for controlling the temperature of the water bath temperature (14),and a water bath for the water bath a ventilation system (17) for generating an air bubble (18), the container opening (28) being formed in the container above the water bath to connect the interior of the container to the test space of the test chamber, the humidifier comprising a cooling device of the temperature control system (16).

A multi-redundant metal framework platinum resistor temperature sensing element specifically comprises a hollow metal framework which is provided with an Al2O3 insulation coating. One end of the metal framework is trumpet-shaped, and the periphery of the other end is provided with a plurality of silver lug plates uniformly distributed along the circumferential direction. Each silver lug plate is connected with a lead-out wire, and the periphery of the silver lug plates is wound with an alkali-free glass fiber rope. The metal framework is wound with a platinum wire. The periphery of the platinum wire and the alkali-free glass fiber rope is coated with a high-temperature-resistant insulation sealing coating. A manufacturing method comprises the following steps: a metal framework stamping step, a surface cleaning step, an Al2O3 insulation coating applying step, a platinum wire winding step, a debugging and spot-welding step, a binding step, and a sealing step. By applying air and fuel-lubricating oil temperature sensors assembled by the temperature sensing element of the invention, as a measured medium can flow through the inner and outer surfaces of the metal framework, the conduction area of the medium is increased greatly. Because the framework adopts a metal pipe structure, the thermal conduction coefficient is increased, the conduction thickness is decreased, and the sensor time constant is increased greatly.

This invention discloses a resistance field emission electron negative electrode part, which is characterized by that the electron negative electrode part is located with row electrode or line electrode and it sets resistance between the row and down electrode or line or down electrode. The feedback action of the resistance can stabilize the emission and when row electrode is loaded with negative voltage and the line electrode is loaded with positive voltage, the electron injects form down electrode to the transmission layer and is accelerated and achieves the upper electrode and the part of electrons passes the upper electrode and are emitted to the vacuum.

The invention relates to a thermal-insulating device of a thermal control system of an aerial camera. The thermal-insulating device comprises three stainless steel bolts and three thermal-insulating gaskets, which are symmetrically distributed along the axial direction, wherein a circular thermal-insulating pad is arranged between a first structure element and a second structure element; the thermal-insulating gaskets are arranged between an annular surface of each stainless steel bolt and a plane of the first structure element; the thermal-insulating gaskets, the first structure element, the thermal-insulating pad and the second structure element are fixedly connected through the stainless steel bolts; three symmetrically distributed bosses respectively extend from the first end face and the second end face of the thermal-insulating pad; the surfaces of three bosses at the first end face contact the plane of the first structure element; the surfaces of three bosses at the second end face contact the plane of the second structure element; a connection section of the stainless steel bolts penetrates through a through hole at the center of each boss; the boss structure is used for increasing the heat resistance and the contact heat resistance of the thermal-insulating pad; the heat of the first structure element is isolated through the thermal-insulating pad and the thermal-insulating gaskets; the heat is prevented from being directly transmitted to the second structure element from the first structure element; and the heat is also prevented from being conducted through the stainless steel bolts.

The invention discloses a switched capacitor biasing circuit capable of reducing the power consumption of an operational amplifier. The switched capacitor biasing circuit comprises a P type current source tube biasing unit SCP and an N type current source tube biasing unit SCN. The biasing circuit utilizes the capacitor divider to transmit input signals quickly; the interference caused by the clock feedthrough effect is small; different biasing voltages can be generated without complex front-end bias generation circuit, thus the chip area is saved; and no direct current path is needed, so that no additional power consumption is increased. The switched capacitor biasing circuit can be widely applied to any operational amplification circuit working under certain switching frequency, and help the operational amplifier to achieve relatively low power consumption and quick signal establishment.

The invention provides a reconfigurable composite waveform generation circuit. The reconfigurable composite waveform generation circuit comprises a constant-current charging module, a threshold setting module and a logic judgment module, in two branches of the constant-current charging module, one branch generates an output waveform signal, and the other branch controls the duration of a direct-current level; the threshold value setting module compares the input waveform signal voltage value, the direct current level and the preset threshold value of each key node, and outputs a mark signal to the input end of the logic judgment module; and the logic judgment module performs logic judgment according to a mark signal input by the threshold setting module, and outputs a switch control signal to be fed back to the two charging branches in the constant-current charging module. The analog circuit, the threshold setting module and the simple logic control unit are combined, output of direct-current level, sawtooth wave and direct-current and sawtooth wave time division multiplexing waveforms is achieved, hardware cost is low, software configuration is not needed, simple and continuous adjustment can be achieved, and flexibility is high.