911 results about "Charge amplifier" patented technology

A system is disclosed for enhancing the stimulation signal bandwidth for a touch sensor panel and maintaining relatively uniform touch sensitivity over the touch sensor panel surface. In one embodiment, a bandwidth enhancement circuit is coupled in parallel to a sensor circuit. The sensor circuit includes a source of stimulating voltage, a drive line, a sense line, and a charge amplifier. The drive line and the sense line are coupled with each other by a mutual capacitance Csig. The bandwidth enhancement circuit can be a RC circuit coupled in parallel to the sensor circuit. The bandwidth enhancement circuit can be represented by two serially coupled resistors, each of which is also coupled to ground on one end, and two capacitors. In particular, one of the capacitors couples the bandwidth enhancement circuit to the drive line, and the other capacitor couples the bandwidth enhancement circuit to the sense line.

The present invention relates to a fingerprint sensor element, comprising a sensor electrode (11) formed in an upper conducting layer (M3), a lower electrode (17, 32) formed in a lower conducting layer (M2, P2) and at least one insulating layer (8, 9, 10, 22) between the upper conducting layer (M3) and the lower conducting layer (M2, P2). It further comprises a charge amplifier (13) having a negative (12) and a positive (14) input terminal and an output terminal (18). An upper side (11a) of the fingerprint sensor electrode (11) is arranged for facing a finger (5) and a lower side (11b) is arranged for facing the lower electrode (17), and the fingerprint sensor electrode (11) and the lower electrode (17) are arranged in such a way that a capacitance (Cref) is formed between them. The sensor electrode (11) is arranged for being connected to the negative input terminal (12) of the charge amplifier (13), and the lower electrode (17) is arranged for being connected to the output terminal (18) of the charge amplifier (13).

Various embodiments of methods and apparatus for an amplifier with wide output voltage swing are disclosed. The amplifier may include multiple output stages, each associated with a distinct supply voltage. Each output stage may contribute current to the output of the amplifier over a range of amplifier output voltages and these ranges may overlap. Each output stage may contribute current until the amplifier output voltage reaches the supply voltage associated with that output stage. The amplifier output may be as great as the largest supply voltage minus a drop equal to Rdson for an output transistor multiplied by the output current. In a CMOS implementation, this voltage drop may be approximately 0.15V. When the amplifier output voltage is close to the supply voltage associated with an output stage, both that output stage and the output stage associated with the next highest supply voltage may contribute to the amplifier output.

There is disclosed a multi-stage amplifier comprising: a first amplifier stage; a second amplifier stage; a first voltage supply stage arranged to provide a supply voltage to the first amplifier in dependence on an average power of a signal to be amplified; and a second voltage supply stage arranged to provide a supply voltage to the second amplifier in dependence on an instantaneous power of a signal to be amplified.

The invention relates to a dynamic characteristic parameter test device of a sliding guide rail junction surface, which can be simplified into a single degree of freedom system. The device comprises a base, an installation platform, a fixed guide rail, a wedge-shaped block, an inlaid strip, a sliding block, a plurality of piezoelectric type acceleration sensors, a vibration exciter, an elastic rope, an impedance head, a stand, a normal force applying bolt, a rubber ring, a charge amplifier, a data acquisition unit, a power amplifier and an electronic computer. Compared with the prior art, thedynamic characteristic parameter test device has the advantages that: the structure is compact, the test principle is distinct, dynamic characteristic parameters of the junction surface under different load states can be measured by adjusting the pretightening force of a normal force applying bolt, the vibration exciting force direction passes through the gravity of the sliding block during measurement so that vibration signals of the sliding block and the base can be measured simultaneously, the influence of the vibration signals of the base is eliminated when a frequency response function of a system is calculated, and the characteristics of high efficiency, high stability and high precision are achieved.

The invention realizes certainly detecting two or more positions on a touch panel that are touched at the same time. A drive circuit selects one from X lines, and supplies an alternating drive voltage to the selected line. A multiplexer selects a first sense line and a second sense line from Y lines that extend to cross the X lines. A charge amplifier outputs an output voltage corresponding to a difference between a first capacitance between the first sense line and the X line selected by the drive circuit and a second capacitance between the second sense line and the X line selected by the drive circuit. A touch position is then detected based on the output voltage of the charge amplifier.

The present invention relates to a capacitive fingerprint sensing device comprising a semiconductor substrate; and an array of sensing elements formed on the semiconductor substrate. Each of the sensing elements comprises a protective dielectric top layer; a sensing structure arranged underneath the top layer; and a charge amplifier connected to the sensing structure. The charge amplifier comprises a negative input connected to the sensing structure; a positive input; an output providing a sensing signal; a feedback capacitor; and a sense transistor having a gate constituting the negative input. The sense transistor is formed in an insulated well in the semiconductor substrate. The fingerprint sensing device further comprises excitation signal providing circuitry connected to the positive input of the charge amplifier and the well for changing electric potentials of the sensing structure and the well, to thereby reduce the influence of parasitic capacitances in the sensing element.

A test and analysis system of digital machine process-dynamics character comprises hardware prepared as arranging acceleration transducer at tail end of cutter, connecting hammer and said transducer to electric charge amplifier being connected to data collector and carrying out data transmission with computer by said collector; and software formed by man-machine interactive boundary and module of data collection, data play-back, hammering test, transmission function analysis, parameter identification, noise test and analysis.

The invention discloses a falling multifunctional measuring device for an impact test of soft composite materials, comprising an impact test unit. The device is also provided with a transient force and displacement testing unit which comprises a sensor supporting sleeve, a piezoelectric force sensor, a grating bar, a photoelectric sensor, a stabilized voltage supply, a charge amplifier and a signal amplifier. The testing unit can be arranged in the impact test unit in a detachable way; the piezoelectric force transducer is positioned in the sensor supporting sleeve, and the input end thereof is connected with the charge amplifier; the sensor supporting sleeve is arranged at the upper end of a hammer head; the grating bar and the sensor supporting sleeve are positioned at the same horizontal line; the grating bar can move synchronously with the hammer head and a base thereof is provided with the photoelectric sensor; the photoelectric sensor is positioned below the grating bar and the excitation voltage thereof is provided by the stabilized voltage supply; and the signal output end of the photoelectric sensor is connected with the signal amplifier. The device has simple structure, high integration level and low cost, and can provide testing data of composite materials in a small energy test.

A battery charger is provided. The charger includes an AC input for connection to a source of AC power and a plurality of DC outputs each being connectable to a battery bank. A user interface is provided for inputting battery information including battery voltage and battery type for each DC output. A main controller is in communication with the user interface and receives the battery information from the user interface. The main controller uses the battery information to provide independent charging instructions for each DC output. At least one power module is in communication with the main controller and receives the charging instructions from the main controller. The power module is configured to convert the AC power from the AC input to DC power and is selectively connectable with each of the plurality DC outputs. The power module is configured such that the charging instructions from the main controller direct the power module as to which DC output to connect and a charge voltage and a charge amps to be provided by the power module to that DC output.

A solid-state imaging device comprises: a plurality of pixels including a light-sensitive portion (2) for photoelectrically converting incident light, a transfer gate (10) for transferring a charge stored in the light-sensitive portion, a resettable detection capacitor (18) for storing the charge transferred from the transfer gate, and a selection switch (26) for outputting a charge of the detection capacitor according to a selection signal RWn; a charge amplifier (41) for converting the detection capacitor charge, which is outputted from the pixels, to a voltage; and a correlated double sampling circuit (86) for obtaining a voltage difference between a reset level and a detected level converted by the charge amplifier. According to the above device, a thermal noise is eliminated due to the correlated double sampling circuit. Further, a fixed pattern noise is not generated due to the pixel circuit structure.

The invention relates to a flexible film tactile sensor which is formed by an electroactive polymer film matrix, a carbon nanotube composite film electrode layer, an electrode lead, and a polyimide film protection layer. The carbon nanotube composite film is a multi-layer network-shaped film composed of a carbon nanotube and polymer electrolyte; an electrostatic induction self-assembly method is used to make a pair of compliant electrode layers on upper and lower surfaces of the electroactive polymer film matrix; a peripheral electrode anchor zone through a metal electrode lead is integrated with a charge amplifier as a whole to from a tactile sensor; and a microprocessor or a computer is used to realize signal acquisition, storage, display and processing. The flexible film tactile sensor can be closely adhered to the surface of the measured object so as to measure the tactile perception performance of the object, can be cut into any shape, and has the characteristics of being reliable, flexible, rapid in response, and the like.

The invention relates to a system and a method for measuring time-sharing quick steady-state sine sweep excitation frequency response function, which belong to the technical field of vibration tests. An excitation system adopts a vibration exciter and a power amplifier. A force sensor and a vibration sensor are adopted to measure an exciting force signal and a vibratory response signal of the system at the same time. A charge amplifier is adopted to condition and filter the signals. A data acquisition system connects a data acquisition card with a connecting terminal through a high-performance shielded cable and is connected with a general computer to acquire and send data. The generation of a sweep signal and the data processing, analysis, storage and display of an exciter response signal are achieved by adopting software based on the general computer. The system and the method achieve quick steady-state sine sweep excitation, the complete cycle sampling of the exciter response signal, and precise and reliable frequency response function curve. The test system is guided by computer programs and is finished automatically, the test method is precise and reliable, and the system and the method have important meaning on testing the dynamic properties of structural elements.

A variable-gain wide-dynamic-range amplifier including an amplifier module, a control unit, and an output current regulating circuit is provided. The amplifier module amplifies an input signal. The amplifier module includes several amplifier units coupled to each other in parallel. The gains of the amplifier units are different. The control unit enables at least one of the amplifier units according to a gain control signal. The at least one of the amplifier units which is enabled is for outputting a current signal in response to the input signal. The output regulating circuit is for receiving the current signal and outputting an output signal accordingly by regulating the magnitude of the current signal under the control of the control unit. Each of the amplifier units is coupled to the output current regulating circuit in series. The control unit is for controlling the output current regulating circuit according to the gain control signal.

The invention provides a health monitoring system for a concrete structure. The health monitoring system comprises a sensor subsystem, a data acquiring subsystem, a communication system and a monitoring center. The sensor subsystem comprises a piezoelectric intelligent aggregate sensor and other sensors, wherein the piezoelectric intelligent aggregate sensor is used for monitoring cracks of the concrete structure, a piezoelectric force sensor is used for acquiring impact load of the structure, and an acceleration sensor is used for obtaining structural vibration information. The data acquiring subsystem is mainly composed of a data acquisition card and ancillary facilities including a piezoelectric ceramic driving power supply, a charge amplifier and the like. A communication subsystem adopts a wired mode and is communicated with an upper computer in a mode that a transmission control protocol (TCP) / Internet protocol (IP) is built in Ethernet. The monitoring center mainly comprises a driving monitoring module, a driven monitoring module, an acceleration monitoring module and other software functional modules. The health monitoring system for the concrete structure is simple to operate, and strong in man-machine interaction, can be expanded according to actual requirements at a later stage, and is very suitable for health monitoring of the concrete structure in practical engineering.

The invention relates to a device and a method for detecting pipeline closed cracks based on the vibro-acoustic modulation technology and belongs to the pipeline nondestructive testing field. The device provided by the invention comprises a computer, a first function generator, a second function generator, a first power amplifier, a second power amplifier, a vibration exciter, an accelerometer, acharge amplifier, a first thickness concertina-type piezoelectric ceramic sheet array and a second thickness concertina-type piezoelectric ceramic sheet array, an anti-aliasing filter and a data collection card. The method provided by the invention comprises the following steps of: acquiring a pipeline first-order bending vibration inherent frequency by swept frequency excitation; taking the frequency as the one of low-frequency vibration in the vibro-acoustic modulation detection; simultaneously exciting low-frequency bending vibration and high-frequency supersonic waves into the pipeline, determining whether there exists closed cracks inside the pipeline by the existence of frequency components which equal high frequency supersonic wave frequency subtracts or adds low frequency bending vibration frequency in a received signal frequency spectrogram. The device provided by the invention is utilized to solve the problem that it is hard to detect closed cracks by traditional methods, and can be applied to detect closed cracks in industrial pipelines.

A resistive level-shifting biasing network is used with a capacitor in parallel to couple FET-based amplifier stages from DC to several GHz in a multi-stage amplifier. The output of the first amplifier stage is connected to the input of the second amplifier stage without a blocking capacitor or level-shifting diodes, allowing a portion of the drain current for the first amplifier stage to be supplied from the second amplifier stage. In a particular embodiment, a distributed amplifier achieved over 20 dB gain from DC to about 80 GHz using three traveling wave amplifier chips.

An electrostatic capacitance detection circuit includes a charge amplifier that has an operational amplifier in which a capacitor is provided on a feedback path, and into which a signal including detection of electric charge of an inter-electrode capacitor of a sensor electrode and electric charge due to an external noise, and a selection switch that can switch a direction of a capacitor that is connected to input and output terminals of the charge amplifier through a feedback path that switches the direction of the capacitor depending on a direction of electric charge flowing in from a detection-side electrode of the sensor electrode, due to a drive signal applied to the sensor electrode.

The invention relates to a capacitive micro-accelerometer which adopts the design of a bulk-silicon processed micro-mechanical structure and the design of an integrated circuit, which pertains to the field of MEMS micro-inertial instruments. The capacitive micro-accelerometer adopts two chips of a micro-mechanical sensor and a signal processing circuit for respective integration, the capacitive micro-accelerometer is carried out by the overall packaging and finally realizes an internal structure of the packaged system; the micro-mechanical sensor of the invention adopts a full-differential micro-mechanical structure sensitive element to be matched with a follow-up circuit; the signal processing circuit comprises a full-differential switched capacitor charge amplifier front-end circuit module with adjustable gain, a back-end cascade circuit module which is composed of a first-order switched capacitor low-pass filter and an instrument amplifier and an auxiliary circuit module which is composed of a reference voltage and bias current generating circuit, a self-test circuit and a clock generating circuit. The two-chip proposal of the system of the invention carries out the respective integration and overall packaging, thus simplifying the complexity of the system, reducing the processing cost and the difficulty and improving the performance and the yield.

The invention discloses a common-mode feedback circuit frequency compensation method of a dual-stage amplifier, which belongs to the analog integrated circuit design field. One common-mode feedback circuit is adopted in the dual-stage amplifier to reduce the area and the power consumption of the feedback circuit; the dual-stage amplifier adopts a fully-differential input / output structure; a differential output terminal is used for sampling the common-mode output level; a first-stage amplifying circuit thereof comprises a controllable biasing circuit; a common-mode feedback control signal controls the first-stage common-mode output level and the second-stage common-mode output level of the amplifier at the same time through the controllable biasing circuit; a feedback amplifier is realized by adopting a dual-stage operational amplifier with miller compensation. The left half plane zero point generated by the feedback amplifier in a loop circuit counteracts a certain left half plane pole in a prime amplifier, thereby forming a stable compensation loop circuit. The common-mode feedback circuit frequency compensation method has the advantages of less feedback circuit elements, lower feedback circuit power consumption, high low-frequency loop gain and better compensation phase margin.

The invention relates to the field of flow detection, as an advanced low power consumption two-wire system vortex-shedding meter, comprising a piezo-electric transducer, a differential charge amplifier, a voltage amplifier, a programmable amplifier, a low pass filter, a voltage follower, a band-pass filter set, a band-pass select switch circuit, a peak detection circuit, a wave shaping circuit, asinglechip, a human-computer interface circuit, a 4-20mA output and power management circuit, a constant flow source, a temperature sensor, a pressure sensor, a differential amplifier and a 16-bit analog-to-digital converter. Mini FFT spectral decomposition is used to be combined with the analog band-pass filter set to process signals of a vortex sensor and a multicycle frequency measurement method of precision is used, thereby having temperature and pressure compensating circuit and function, outputting 4-20mA direct current and having two-wire system work. The advanced low power consumptiontwo-wire system vortex-shedding meter has greatly improved measure ratio, measurement precision and capacity of resisting disturbance.

The invention relates to a flexible mechanical arm vibration reduction device and method based on a magneto-rheological technology, which belongs to the technical field of flexible mechanical arm vibration control. The vibration reduction device comprises a rigid-flexible coupled mechanical arm, a magneto-rheological elastomer vibration reduction device and a feedback control loop, wherein the rigid-flexible coupled mechanical arm comprises a rigid mechanical arm, a motor mounting plate, a servo motor, a harmonic reducer, a flexible mechanical arm mounting base and a flexible mechanical arm; the magneto-rheological elastomer vibration reduction device comprises an iron core, a guide rod, a fixed seat, a magneto-rheological elastomer, a permanent magnet and an electromagnetic coil; and the feedback control loop comprises two acceleration sensors, a charge-amplifier, a data acquisition system, a PC (Personal Computer) upper computer and a programmable power supply. The PC upper computer is used for regulating the supply voltage of two ends of the electromagnetic coil through the analyzing and processing the feedback signals of the two acceleration sensors so as to change the rigidness of the magneto-rheological elastomer, thereby meeting the resonance requirement in a system. The flexible mechanical arm vibration reduction device has the characteristics of obvious vibration reduction effect and less energy consumption and is suitable for large amplitude vibration reduction.

The invention discloses a GIS (Geographic Information System) fault diagnosis system and method based on vibration signal spectrum analysis, belonging to the field of GIS fault monitoring. The system comprises a vibration acceleration sensor, a charge amplifier, a data acquisition instrument and a PC (Personal Computer) all of which are successively connected together in series, wherein the vibration acceleration sensor comprises three vibration sensors which are fixed on the outer surface of a GIS box in the X-axis, Y-axis and Z-axis directions, respectively. The diagnosis method of the system comprises the following steps of: acquiring GIS vibration signals in the X-axis, Y-axis and Z-axis directions by means of the three vibration sensors; performing wavelet de-noising on the vibration signals intercepted by a full period and then performing spectrum analysis; calculating energy at 50 Hz and the sum of energy at 100 Hz, energy at 200 Hz and energy at 300 Hz respectively; comparing the calculated values with the normal state; and determining the GIS fault according to the result of comparison in combination with a threshold. The method is easy in engineering realization, obvious in feature and capable of effectively diagnosing the GIS fault.

The invention discloses a device and method for performing modal testing on an inflatable flexible film structure based on a hammering excitation method. A force hammer is used for knocking a marked excitation point of the inflatable flexible film structure so as to apply vibrational excitation, a force sensor installed on the force hammer receives force signals, and an acceleration sensor installed on the surface of the inflatable flexible film structure receives acceleration signals; after the force signals and the acceleration signals are amplified by a charge amplifier, a data acquisition instrument inputs received acceleration electrical signals and force electrical signals into a computer, the computer performs digital-to-analogue conversion on the signals and obtains a frequency response function matrix according to the force signals and the acceleration signals, and finally modal vibration shapes of all orders and related modal parameters of the structure are obtained through parameter identification. Thus, modal numerical simulation of the inflatable flexible film structure can be verified and provided with reference. The device is simple in structure, convenient to operate and wide in application range.

The invention relates to a test platform and method for simulating intelligent flexible space panel structure vibration active control. The test platform includes a mechanical clamping device, a vibration flexible plate, a signal generator, a high-performance DSP board, an oscillator, a computer, a display device, a vibrator, a plurality of charge amplifier, a plurality of low-pass filter, a plurality of piezoelectric power amplifier, a piezoelectric plate sensing network and a piezoelectric driving network. The invention which uses piezoelectric ceramic element as basic materials of sensor network and driver network, DSP measuring element as core of signal detection, arithmetic operation and output control signal, PC machine as test control platform and observing interface provides a test platform and test method based on analog piezoelectric intelligent flexible space panel structure vibration active control research.

The invention relates to a device for testing dynamic characteristic parameters of a fixed joint surface of a single-degree-of-freedom system. The device comprises a base, a lower experimental plate, an experimental sample wafer, an upper experimental plate, a piezoelectric acceleration transducer, a bolt, a bracket, a vibration exciter, an impedance head, a charge amplifier, a digital analyzer, a power amplifier, an electronic computer, a normal coupling bolt hole, a lower experimental plate coupling bolt, a tangential coupling bolt hole and a flexible rope. Compared with the prior art, the device has the remarkable advantages of compact structure and clear testing principle; the dynamic characteristic parameters of a normal contact surface and a tangential contact surface can be simultaneously measured; the dynamic characteristic parameters of the contact surfaces in different load states can be measured by adjusting the pre-tightening force of the coupling bolt of the upper experimental plate and the lower experimental plate; the excitation force passes through the center of gravity of the upper experimental plate during measurement; vibration signals of the upper experimental plate and the lower experimental plate are simultaneously measured; the influence of the vibration signal of the base is eliminated during the calculation of a frequency response function of the system; and the device has the characteristics of high efficiency, stability and accuracy.

A measuring circuit for a proximity sensor, comprising a charge amplifier in a floating voltage domain that is driven by a square waveform. The output signal is sampled synchronously with the voltage of the floating domain, and demodulated by measuring the voltage steps amplitude. This approach is compatible with a switched capacitor implementation and allows discriminating the capacity signal from the ambient noise; the latter can be evaluated independently.

The invention provides a system for monitoring loosening parts of a nuclear reactor and a coolant system, solving the problems of reliability, compatibility, stability and maintenance convenience andcomprising an accelerometer, a charge amplifier, signal conditioning equipment, loosening part detection equipment, alarm processing equipment, sound monitor equipment, data collection equipment, a display, loosening part monitor software and the like. The system adopts a PXI bus technology so as to enable every two modules to be synchronized; a signal conditioning module adopts an FPGA programmable technology; a DSP digital technology is adopted to discriminate a loosening part event; loosening part signal length effective value floating discrimination, time delay, channel recheck combination discrimination, alarm prohibition caused by alarm channel recheck, control rod motion or coolant low pressure, and the like ensure that the system has a strong wrong alarming resistance capacity; the data collection equipment collects data to replace tape records so as to ensure the integrity of event signal records; and event signal waveform display and data storage can carry out display back and secondary analysis on signals.