436 results about "Variable capacitor" patented technology

A ground detection system for an aircraft based on capacitive sensing. The system comprises an electrode mounted to an aircraft landing gear. As the aircraft landing gear approaches the ground, the electrode and the ground together form a variable capacitor having a capacitance that depends on a distance of the electrode from the ground. Signal processing electronics are used to measure the capacitance and, on the basis of the measured capacitance, determine a distance of the aircraft from the ground.

A low-phase noise class-D voltage-controlled oscillator based on a broadband harmonic shaping technology comprises a head resonance unit, an LC resonance unit composed of a first inductance unit, a second inductance unit and a first capacitance unit, a negative resistance unit, a variable capacitance unit, an array capacitance unit and an output unit. The output end of the head resonance unit is connected with one end of the first inductance unit, the other end of the first inductance unit is connected with one end of the negative resistance unit, the other end of the negative resistance unit is connected with the first capacitor unit, the first capacitor unit is connected with the variable capacitor unit, and the variable capacitor unit is connected with one end of the array capacitor unit. The other end of the array capacitor unit is connected with one end of the second inductor unit, the other end of the second inductor unit is grounded, two input ends of the output unit are connected with the variable capacitor unit, and two output ends of the output unit serve as output ports of the voltage-controlled oscillator.

Disclosed are a micro-electromechanical system (MEMS) structure and an MEMS microphone comprising same. The MEMS structure comprises a back plate; and a diaphragm located on one side of the back plate, wherein the diaphragm and the back plate forms a variable capacitor, the diaphragm comprises multiple first through holes and air release structures respectively corresponding to the first through holes, and the diaphragm further comprises one or more second through holes penetrating through the diaphragm.

The present disclosure provides to a stretchable display device and a stretchable panel driving circuit, the display device including a stretchable display panel, a gate driving circuit configured to supply gate signals to pixels through gate lines, a data driving circuit, at least one stretch detection circuit group including at least one delay cell and at least one stretch variable capacitor disposed in a non-display area of the display panel, and configured to detect a delay time caused by stretch, a compensation control signal generator configured to generate a compensation control signal based on the delay time, and a timing controller configured to output a compensated signal based on the compensation control signal.

The invention discloses a pressure or pre-tightening force monitoring intelligent gasket using an etching circuit, and the gasket comprises a pressed region disposed in the inner periphery, and the pressed region is provided with a variable capacitor whose capacitance value is in an expressible relationship with the pressure; the non-compression area is arranged on the periphery and provided with a metal substrate, and a frequency conversion circuit, a resonance circuit and a radio frequency antenna are etched on the metal substrate; the resonant circuit and a variable capacitor form an LC parallel resonant circuit based on an inductance element, the capacitance value of the capacitor is changed through the change of pressure or pre-tightening force borne by the variable capacitor, so that resonant signals with different resonant frequencies are generated, and the resonant signals are transmitted by a radio frequency antenna after being subjected to frequency conversion through a nonlinear electronic component of a frequency conversion circuit. Therefore, pressure or pre-tightening force monitoring of the to-be-measured bolt is realized. The intelligent gasket, especially the antenna circuit structure, is simplified, the circuit and the antenna obtained through the etching technology are low in power consumption and stable in signal, and the intelligent gasket has the advantages of being convenient to deploy, long in service life, easy to maintain and the like.

The invention provides a delay circuit applied to a time-interleaved analog-to-digital converter, the circuit comprises a first delay module, a second delay module and a delay selector, the first delay module is composed of multiple stages of delay units connected in series, each stage comprises a fixed inductor connected in series and a variable capacitor connected in parallel, and is used for providing large-range adjustable delay; the second delay module is connected to the output end of the first delay module and comprises a parallel combination of an adjustable constant current source and a programmable capacitor array, high-precision delay adjustment is achieved, the minimum adjustment step length of the second delay module is smaller than that of the first delay module, and multiple input ends of the delay selector are connected with output nodes of all stages of delay units respectively. The selection module is used for selecting coarse delay signals in different stages; the circuit realizes low-noise coarse delay adjustment through the inductance-capacitance network, completes high-precision fine delay adjustment by using current-capacitance combination, and has the advantages of wide delay range, high adjustment precision, low noise, good stability and the like.

The invention discloses an automatic impedance range calibration method for a radio frequency matcher, which comprises the following steps of: driving a variable capacitor of a standard matcher according with a design standard to scan and record impedance data under the connection mode that the input end is connected with a standard load and the output end is connected with a network analyzer and the specific configuration of the network analyzer; establishing a standard impedance range database; performing equivalent impedance scanning on the matcher to be calibrated in the same connection mode, and recording data; comparing the impedance data of the matcher to be calibrated with the standard database to determine an effective working interval of the capacitor; and finally, writing the effective interval as a limit into the control configuration of the matcher to be calibrated, and limiting the capacitance adjustment range of the matcher to be calibrated during normal operation. The automatic calibration system comprises a standard impedance measurement unit, an automatic control and data processing unit and a calibration execution unit. And the whole calibration process is controlled by a program, manual intervention is not needed, and the production efficiency is remarkably improved.

The invention discloses an MEMS (Micro Electro Mechanical System) chip, a preparation method of the MEMS chip, a micro electro mechanical system gas sensor and a gas detection device. The MEMS chip comprises a first pole plate and a second pole plate, a cavity is formed between the first pole plate and the second pole plate, a dielectric substance in the cavity is gas, the first pole plate is provided with a first vent hole, the cavity is communicated with the outside through the first vent hole, and the second pole plate is provided with a second vent hole. The mechanical resonant frequency of the first polar plate is far greater than the frequency of sending voltage excitation to the MEMS chip by an ASIC (Application Specific Integrated Circuit) chip, or both the mechanical resonant frequency of the first polar plate and the frequency of sending voltage excitation to the MEMS chip by the ASIC chip are 60 kHz to 100 kHz; the first pole plate and the second pole plate form a variable capacitor, and the dielectric substance of the variable capacitor is gas, so that the sensitivity of the MEMS gas sensor using the MEMS chip can be improved.

The embodiment of the invention discloses a photovoltaic system and a parallel operation circulating current suppression method thereof, the photovoltaic system comprises a plurality of power converters connected in parallel, each power converter comprises an inversion module, an output filter, a detection circuit and a controller, and the output filter comprises a variable inductor and / or a variable capacitor. The variable inductor comprises a first winding connected with the first switching circuit in series, and the controller can control the first switching circuit to be switched on or switched off according to the current value, detected by the detection circuit, flowing through the output filter so as to change the inductance value of the variable inductor. The variable capacitor is connected in series with the second switching circuit between the neutral line and the alternating current bus, and the controller can control the second switching circuit to be switched on or switched off according to the current value which is detected by the detection circuit and flows through the output filter so as to change the state that the variable capacitor is connected to the alternating current bus. By changing the inductance value and / or the capacitance value, the position of the resonant frequency point of the output filter can be changed, so that the parallel operation circulating current is inhibited.

Embodiments of the present disclosure provide a system for fast impedance tuning. The system includes a radio frequency (RF) generator to generate power, a plasma chamber to receive the power from the RF generator and a RF matching network inserted between the RF generator and the plasma chamber configured to match a plasma load impedance to a RF generator impedance using a solid state based variable capacitor. The RF matching network includes a bias circuit that applies a reverse bias to the solid state based variable capacitor to control a capacitance value of the solid state based variable capacitor. The plasma load impedance is matched with the RF generator impedance when pulsed voltage, multi-level pulsing, or RF match ignition tuning is applied.

A plasma processing apparatus includes a vacuum container and a plasma source that generates plasma in the vacuum container. The plasma source includes an antenna, an RF power supply connected to one end of the antenna and configured to supply an RF power to the antenna, and a variable capacitor connected to the other end of the antenna and having a variable capacitance.

The invention relates to the technical field of network analyzers, and aims to solve the technical problem of low radio frequency power output precision. In order to solve the technical problem, the invention provides a temperature compensation pre-detection high-precision amplitude stabilization method and a network analyzer. The method comprises the following steps: detecting the temperature of the output end of a radio frequency main circuit; after the collected temperature value is calculated, the detection circuit outputs a compensation voltage value, meanwhile, reference voltage is output to the detection circuit, and after the compensation voltage value, the reference voltage and the voltage value of the detection circuit are summed, a correction voltage value is output; and the variable voltage carries out amplitude stabilization on the correction voltage value according to the acquired temperature value. The system also comprises a radio frequency main circuit, a detection circuit, an amplitude stabilizing circuit, a temperature detection circuit and a control assembly. The temperature detection circuit is provided with a temperature sensor; and an acquired temperature adjusting module of the control assembly is electrically connected with the temperature sensor and the variable capacitor respectively. The radio frequency power output precision is greatly improved.

A capacitance measurement circuit includes a charge to voltage converter (CVC) that includes at least one first variable capacitor, an excitation signal generation circuit, a differential amplifier, a first switch circuit, and at least one second variable capacitor, wherein a parasitic capacitance from a sensing capacitance sensed by a capacitance sensor is reduced by the at least one first variable capacitor. The excitation signal generation circuit is arranged to generate and connect a first excitation signal to the capacitance sensor, and generate and connect a second excitation signal to the at least one first variable capacitor, wherein the first excitation signal and the second excitation signal are out-of-phase, and a voltage amplitude of the first excitation signal is different from a voltage amplitude of the second excitation signal. The inverting input terminal of the differential amplifier is arranged to receive the sensing capacitance from the capacitance sensor.

Early warning systems and methods for determining capacitor failures are described. One of the methods includes controlling a motor to further control a variable capacitor that is coupled to the motor to facilitate achieving a hard stop position or a home position of the variable capacitor for multiple times. Each time the motor is controlled to facilitate achieving the home position or the hard stop position, a number of steps that are taken by the motor are recorded. The numbers of steps are compared with each other to determine whether the variable capacitor has failed.

The utility model discloses a connecting structure of a variable capacitor, which comprises a mounting bracket, a bearing and a joint, and is characterized in that the mounting bracket adopts an integrated structure and is used for being fixedly connected between a driving motor of the variable capacitor and an outer shell; the bearing is embedded in the mounting bracket and is used for bearing the screw rod of the variable capacitor; and the joint is arranged in the mounting bracket and is used for fixedly connecting the output shaft of the driving motor with the screw rod. The connecting structure of the variable capacitor is simple and reasonable, the coaxiality between the output shaft of the driving motor and the screw rod is effectively improved, and the capacitance value control precision of the capacitor is improved; the volume and the manufacturing cost of the capacitor and the impedance matcher are greatly reduced; and the user requirements are met.

An oscillator circuit, a corresponding radar sensor, a vehicle, and an operating method are disclosed. An oscillator includes a tunable resonant circuit having an inductor and a variable capacitor coupled between a first node and a second node, and a set of capacitors selectively coupled between the first node and the second node. An input control node receiving an input control signal is coupled to the variable capacitor and the set of capacitors. The tunable resonant circuit is tunable based on the input control signal. A biasing circuit biases the tunable resonant circuit to generate a variable frequency output signal between the first node and the second node. A voltage divider generates a set of different voltage thresholds, and a set of comparator circuits having hysteresis compares the input control signal with the set of different voltage thresholds to generate a set of control signals. The capacitors in the set of capacitors are selectively coupled between the first node and the second node according to the control signals in the set of control signals.

The invention relates to the technical field of radio frequency integrated circuits, and discloses a low-noise voltage-controlled oscillator circuit which comprises a source electrode following low-noise bias circuit with digital calibration, a source electrode following low-noise bias circuit with digital calibration, a source electrode following low-noise bias circuit with digital calibration and a source electrode following low-noise bias circuit with digital calibration, the cross-coupled amplifier array is composed of a plurality of units, and the source electrode of the cross-coupled amplifier array suppresses low-frequency noise through a resistance-capacitance feedback network and receives a digital amplitude calibration signal so as to dynamically adjust the number of working units and stabilize the output amplitude; the amplitude self-calibration loop consists of digital logic and a peak detector; the switched capacitor unit array is provided with stable direct-current bias; and a wide linear variable capacitor array driven by the stepped bias voltage. Through deep fusion of digital and analog technologies, the phase noise is remarkably reduced, the linear tuning range is widened, the amplitude stability is ensured, the power consumption is reduced, and the method is particularly suitable for a high-performance radio frequency communication chip of the Internet of Things.

A plasma processing apparatus includes a chamber, a bias power supply to supply a pulsed bias DC signal, a substrate support to support a substrate and an edge ring in the chamber, and an electrical path. The substrate support has an electrostatic chuck that includes a first region to hold the substrate and a second region provided around the first region and to hold the edge ring, and is formed from a dielectric, a first bias electrode inside the first region, a second bias electrode inside the second region, a base to support the electrostatic chuck, and a first impedance adjustment mechanism to have a first variable capacitor connected between the second bias electrode and the base.

The invention relates to the technical field of radio frequency integrated circuits, and discloses a dynamic bias C-type voltage-controlled oscillator based on a CMOS (complementary metal oxide semiconductor) process, the voltage-controlled oscillator adopts a C-type structure, a cross-coupled network adds two resistors and a capacitor on the basis of a cross-coupled transistor, a circuit works in the C type by adjusting bias voltage at a resistor end, and the voltage-controlled oscillator works in the C type. The C-type voltage-controlled oscillator, a tail current source, a variable capacitance network, a switched capacitor array and a fixed LC resonance network form a core structure of the C-type voltage-controlled oscillator capable of numerical control tuning and voltage-controlled tuning, so as to determine the working frequency of the circuit and realize numerical control and voltage-controlled tuning functions; and the operational amplifiers with two bandwidth modes are introduced, so that the problem of difficult oscillation starting is solved, and the oscillation starting speed and the phase noise performance in a stable state are considered at the same time.

A display apparatus including a sensor includes: a pixel group including a predetermined number of pixels, each of which includes a pixel circuit and a light-emitting device electrically connected to the pixel circuit; and a sensing pixel including a sensing circuit and a sensing electrode connected to the sensing circuit, where the sensing electrode forms a variable capacitor with respect to a finger, and the sensing circuit is arranged around the pixel circuit of the pixel group.

In one embodiment, an RF impedance matching circuit includes at least one electronically variable capacitor (EVC) comprising discrete fixed capacitors. Each fixed capacitor has a corresponding switching circuit for switching in and out the fixed capacitor to alter a total capacitance of the EVC. Each switching circuit includes a diode operably coupled to the fixed capacitor to cause the switching in and out of the fixed capacitor, the diode being a PIN diode or an NIP diode. Each switching circuit further includes a driver circuit operably coupled to the diode, and a resonant filter positioned between the driver circuit and the diode. The resonant filter includes an inductor and a capacitor coupled in parallel.

The invention discloses an ultra-wideband voltage-controlled oscillator circuit, relates to the technical field of semiconductor integrated circuits, and is used for solving the problems of electromagnetic interference risk, narrow frequency regulation range and relatively high power consumption of a voltage-controlled oscillator in the prior art. Comprising a switched capacitor array, a transformer load switch inductor, a variable capacitor and a cross coupling tube, two ends of the transformer load switch inductor are respectively connected with two ends of the switch capacitor array, and the transformer load switch inductor is connected with the switch capacitor array in parallel; the two ends of the switched capacitor array are respectively connected with a variable capacitor, and the variable capacitors are connected with the cross coupling tube. By adopting the 8-shaped transformer load switch inductor, the output frequency regulation range of the single-core voltage-controlled oscillator is expanded, and the problem of serious frequency disturbance caused by electromagnetic interference to an external circuit module is solved. Compared with other single-core LCVCOs, the multi-core multi-mode LCVCOs have a wider frequency regulation range, and compared with other multi-core multi-mode LCVCOs, the multi-core multi-mode LCVCOs have a smaller area and lower power consumption.

The invention discloses an impedance matching method and system for chip testing, electronic equipment and a medium, and relates to the technical field of data processing. The method comprises the following steps: establishing electrical connection between a test probe and a to-be-tested chip test point, and sending a preset detection signal; acquiring incident power and reflection power of the detection signal; calculating a first signal reflection coefficient based on the incident power and the reflection power, and determining an impedance deviation value and an adjustment direction according to a difference value between the first signal reflection coefficient and a preset standard reflection coefficient; determining a parameter adjustment step length according to the impedance deviation value; sequentially adjusting a variable resistor, a variable capacitor and a variable inductor in the impedance matching network according to the step length and the adjusting direction; detecting a second signal reflection coefficient when the impedance real part and imaginary part of the variable element reach the target range; and judging whether the second signal reflection coefficient converges to a preset range, and if yes, taking the current matching network parameter as an impedance matching result. By implementing the technical scheme provided by the invention, the impedance matching accuracy of the chip test can be improved.

A capacitance measuring circuit includes a charge-to-voltage converter including at least one first variable capacitor, an excitation signal generating circuit, a differential circuit, a first switching circuit, and at least one second variable capacitor. Wherein a parasitic capacitance value in a sensing capacitance value sensed by a capacitance sensor is reduced by at least one first variable capacitance. The excitation signal generating circuit is used for generating and connecting a first excitation signal to the capacitive sensor and generating and connecting a second excitation signal to the at least one first variable capacitor, the first excitation signal and the second excitation signal are opposite in phase, and the voltage amplitude of the first excitation signal is different from that of the second excitation signal. The inverted input end of the differential amplifier is used for receiving a sensing capacitance value from the capacitance sensor.

In one embodiment, an RF impedance matching circuit is disclosed. The matching circuit is coupled between a plasma chamber and an RF source. The matching circuit includes a first electronically variable capacitor (EVC) having a first variable capacitance, a terminal of the first EVC being operably coupled to the RF input, and a second EVC having a second variable capacitance, a terminal of the second EVC being operably coupled to the RF output. A control circuit determines, based on a first parameter, a first capacitance value for the first EVC and a second capacitance value for the second EVC. The control circuit then generates a control signal to alter the first and second variable capacitances accordingly. The alteration of the capacitances, while the frequency of the RF source is not altered, causes RF power reflected back to the RF source to decrease.

A complementary metal oxide semiconductor (CMOS)-to-current mode logic (CML) converter for converting a CMOS input signal into a CML output signal, including: a low-pass filter comprising a fixed resistor and a first fixed capacitor, and a swing width control circuit configured to adjust a swing width of a voltage swing of the CML output signal based on a common mode level, wherein the swing width control circuit includes: a second fixed capacitor; and a variable capacitor comprising a capacitor array.

The invention provides a Class C inductance-capacitance voltage-controlled oscillator with a wide tuning range, which belongs to the technical field of voltage-controlled oscillators and is composed of an LC resonance circuit and a negative resistance area circuit which are connected in parallel. The LC resonant circuit comprises an on-chip symmetrical spiral inductor, a switched capacitor array, a first variable capacitance tube CV1 and a second variable capacitance tube CV2; the negative resistance area circuit comprises a tail current tube M, a first filter capacitor C1, a second filter capacitor C2, a first cross coupling triode Q0, a second cross coupling triode Q1, a first resistor R0, a second resistor R1, a first filter inductor L3 and a second filter inductor L4; the negative resistance area circuit is connected with the LC resonance circuit; through the switched capacitor array and the two variable capacitance tubes which are matched with each other, the wide tuning range frequency output is realized, and through improving the structure of the switched capacitor array, the anti-interference performance is enhanced, and the phase noise is optimized at the same time.

The invention relates to the field of integrated circuits, in particular to a multi-injection locking annular traveling wave oscillator, a Doppler radar based on the annular traveling wave oscillator and physiological feature detection equipment based on the annular traveling wave oscillator. Comprising 16 inductive elements. Four variable capacitors and four mirror image injection circuits. The inductive elements are sequentially connected end to end. And every two adjacent inductive elements form a phase shift channel and are sequentially distributed in four orthogonal directions. And the two phase shift channels in each direction are parallel to each other and are positioned on the inner side and the outer side of the same layer of the layout. The phase shift channels on the inner and outer sides in adjacent directions are alternately connected, and the wires between the phase shift channels are distributed on the upper and lower layers in the layout at equal intervals. The mirror image injection circuit and the variable capacitor are connected between the two phase shift channels in each direction and output injection signals with the phase difference of 180 degrees to the phase shift channels. According to the invention, the problems of limited injection locking range, high noise and insufficient phase uniformity of the existing oscillator for the Doppler radar are solved.

The utility model relates to the technical field of radio frequency power supplies, in particular to a radio frequency matcher, which comprises a radio frequency input end, a radio frequency output end, a first variable capacitor, a second variable capacitor and an adjustable inductor with a tap, the radio frequency input end is electrically connected to a tap of the adjustable inductor, one end of the adjustable inductor is electrically connected with the first variable capacitor and is connected with the shell through the first variable capacitor, and the other end of the adjustable inductor is electrically connected with the second variable capacitor and the radio frequency output end in sequence. According to the radio frequency matcher, the radio frequency input end is connected to the tap of the adjustable inductor, the adjustable inductor serves as a grounding inductor and a series inductor at the same time to be connected into the matching circuit, one adjustable inductor is used for replacing two inductors in the prior art, the number of the inductors is reduced, and the internal structural layout of the radio frequency matcher is better facilitated. The taps are arranged on the adjustable inductor, and the inductance value of the matching circuit is adjusted by connecting different taps to the radio frequency input end.

In a microelectromechanical system (MEMS) sensor, movement of a component such as a proof mass due to a force of interest is sensed capacitively. A capacitance-to-voltage (C2V) converter receives a capacitance signal from the sensor and outputs a signal that includes an offset in addition to a signal of interest. The output signal is analyzed to identify the offset portion of the output signal and to modify values one or more variable capacitors coupled to the C2V input reduce the offset portion of the output signal.