414 results about "Instrumentation amplifier" patented technology

A multidrop network of multichannel, addressable sensing modules (ASM's), to be embedded within a composite structure, remotely powered, and interrogated by a personal computer through a non-contacting inductive link. Each ASM contains a microprocessor with non-volatile memory, multiplexer, programmable gain and filter instrumentation amplifier, and sigma delta analog to digital converter (all housed in two thin surface mount packages). An embedded mothernode includes circuitry for power and data reception (into the structure), and data transmission (back out of the structure). The external interrogation system communicates into the network of ASM's by modulating the AC waveform that delivers power to the embedded electronics. Once addressed, each ASM powers up its programmable (gain & filter) sensing channels (3 full differential or 5 pseudo differential) and data conversion elements. Sensed data are pulse code modulated, including error checking, which serially modulate an RF carrier for wireless transmission out of the composite to the interrogating computer. These advanced, micro-miniature sensing networks may be applied to a wide variety of military, medical, & civil structures.

A thermocouple measuring circuit for sensing a temperature at a measuring point is provided. The thermocouple measurement circuit (12) includes a thermocouple input for sensing a temperature at a measuring point, a compensation circuit (14) for compensating thermocouple effects of junctions of the thermocouple, and an instrumentation amplifier (16) for summing an output of the thermocouple and an output of the compensation circuit and outputting a voltage indicative of the temperature sensed, wherein the output of the compensation circuit is a reference voltage for the output of the instrumentation amplifier. Various embodiments of the thermocouple measurement circuit may be employed in electrosurgical generators for controlling output power dependent on temperature conditions.

A thermocouple measuring circuit for sensing a temperature at a measuring point is provided. The thermocouple measurement circuit (12) includes a thermocouple input for sensing a temperature at a measuring point, a compensation circuit (14) for compensating thermocouple effects of junctions of the thermocouple, and an instrumentation amplifier (16) for summing an output of the thermocouple and an output of the compensation circuit and outputting a voltage indicative of the temperature sensed, wherein the output of the compensation circuit is a reference voltage for the output of the instrumentation amplifier. Various embodiments of the thermocouple measurement circuit may be employed in electrosurgical generators for controlling output power dependent on temperature conditions.

A patient monitor for determining a probability that a patient has acute cardiac ischemia including an input device connectable to a patient to acquire electrocardiogram (ECG) signals from the patient, an instrumentation amplifier connected to the input terminal to combine the signals and to generate at least one ECG lead, and an analysis module. The analysis module is operable to continuously read the ECG lead, to analyze a portion of the ECG lead for a period of time, and to calculate a probability that the patient has acute cardiac ischemia based at least in part on the analyzed portion of the ECG lead.

A scalable cable management system comprises an electronics module with a microcontroller; a plurality of drive modules and a releasably engaged cable cartridge for each drive module. Each cable cartridge houses a lead wire cable spool with an electrical slip ring connected to the wire. Stationary electrical contacts pickup signals from the slip ring for use by the electronics module. A device such as an electric or spring-driven motor, with a gear train and an optional clutch, controllably rotate the cable spool. A cleaning assembly cleans portions of the lead wire as it is extended or retracted. The microcontroller receives strain signals representative of tension on a lead wire from cable strain gauge. The electronics module may also include a defibrillator protection sub-system, a crossbar transfer switch, an instrumentation amplifier and a communications unit. Test terminals are also provided for assessing integrity of each lead wire.

Chopper stabilized amplifiers combining low clock noise and linear frequency characteristics. The chopper stabilized amplifiers are used in offset correction circuitry, with the output of the chopper stabilized amplifiers being integrated by an integrator. The integrator operates on alternate cycles, with a sample and hold circuit sampling the integrator output when the integrator is not integrating, with the output of the sample and hold being coupled to the main amplification path to cancel offset after at least some amplification is achieved. Autozeroing of amplifiers in the offset correction circuitry is also disclosed. The invention is applicable to operational amplifiers and instrumentation amplifiers.

Chopper chopper-stabilized instrumentation and operational amplifiers having ultra low offset. The instrumentation amplifiers use current-feedback, and include, in addition to a main chopper amplifier chain, a chopper stabilized loop for correcting for the offset of the input amplifiers for the input signal and for receiving the feedback of the output voltage sense signal. Additional loops, which may include offset compensation and autozeroing loops, may be added to compensate for offsets in the chopper stabilized loop for correcting for the offset of the input amplifiers. Similar compensation is disclosed for decreasing the offset in operational amplifiers.

An electrophysiological sensor, weak electrical signal conditioning circuit and method for controlling the circuit as provided. The sensor includes rigid filiform conducting nanostructures connected to a conducting substrate and operable to penetrate an organic tissue. The circuit includes an instrumentation amplifier with an input connected to a first electrode in contact with a first area of a medium, and a second input; a voltage generating device connected to an electrode in contact with a second area of the medium for applying a continuous reference signal to it; a compensator, electrically insulated from the device, for compensating the direct current offsets of a weak electrical signal received by the first electrode, generating a signal with a reference voltage with a value which can be modified by a control system, and supplying it to the second input. A method is also provided for controlling the circuit.

An implantable apparatus for sensing biological signals from an animal includes at least two electrodes disposed at locations to sense the biological signals. The electrode locations may be internal or external to the animal. Insulated conductors couple the electrodes via a passive network of filters to an instrumentation amplifier that has an internal voltage reference. Thus a sensed biological signal is filtered and amplified to provide an amplified differential signal. A signal analysis module processes amplified differential signal to determine at least one physiological parameter of the animal. The signal analysis module may include a first derivative zero detector for signal transition detection and feature detection and analysis. The apparatus may also comprise a signal presentation module to display amplified signals and physiological parameters associated with those signals.

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.

An apparatus and method make use of a single shunt and two or more instrumentation amplifiers, switchably measuring voltages at the shunt. This permits current measurement. At times each instrumentation amplifier has its input shorted, which permits zeroing out many sources of offset in the signal path of that amplifier. Dynamic range is several orders of magnitude better than known current measurement approaches, permitting coulometry.

A wholly implantable non-natural heart for humans is a double pump configuration provided with two auricles and two ventricles. Both the said auricles and ventricles are driven by solenoid actuators interacting with high energy magnets; the auricles and ventricles which are hollow chambers are provided with one-way valves in the usual manner, for the purpose of effectively and rhythmically moving blood to and from the said chambers; power generation for driving said solenoid actuators, as well as an electronic control unit is accomplished by a power generating module which could be a simple battery, a miniature spring-driven generator, a mems generator or a redundant self-sustaining generator or a combination of all of the above; the self-sustaining generator has been proposed and designed to power this present artificial heart and will be presented in a separate patent application in the near future as a follow up to this present one; the aforementioned electronic control unit is preferably configured to amplify the signals from the power generating unit as well as utilizing input / output signals from temperature and pressure sensors embedded in the heart to vary contractile force and frequency of beats, based on bodily requirements, thereby mimicking some functions of the natural heart; the electronic unit is also preferably provided with a translator chip that converts signals from the cardiac / vargus trunks (sympathetic and parasympathetic nerves) via electrodes into clear electric currents for varying actuator outputs; the heart would be implanted in the normal position in the chest, atop the diaphragm, while the electronic control unit and the power generation module would preferably be implanted behind the breastbone and lower abdomen respectively; all components of the present invention are amenable to current mass production techniques and miniaturization for the purpose of fitting into individuals of various sizes; as is clearly shown in FIG. 1, this present invention is an integral three-tiered configuration constituted of pumping unit I, the power generating unit II and the controller III. Also, as aforementioned, additional signals from the embedded temperature and pressure sensors, as well as nerve connecting electrodes are used to manipulate instantaneous outputs. The said electrodes are in the form of cuffs and are to be implanted on the vargus nerves (sympathetic and parasympathetic); Texas Instruments (TI) manufactures reliable operational and instrumentation amplifiers which can detect condition, and amplify nerve signals. The VCO in the controller uses the signals to manipulate instantaneous outputs of the actuating solenoids.

The invention discloses a multi-channel data acquisition device for a submarine pipeline magnetic flux leakage internal detector. The multi-channel data acquisition device comprises a hall sensor, a multi-path switch, an instrument amplifier, an analog-to-digital (AD) conversion module, a field programmable gate array (FPGA), a digital signal processor (DSP) and a secure digital memory (SD) card, wherein the multi-path switch has a two-stage series structure; the multi-channel data acquisition device is provided with heat insulation cotton so as to adapt to a specific high-temperature and high-corrosion environment of a submarine pipeline; the hall sensor converts the magnetic induction density into voltage; the voltage is switched by the multi-path switch, so that a signal is transmitted to the instrument amplifier; the instrument amplifier amplifies a weak signal; the AD conversion module sets sampling for eight times through software, performs analog-to-digital conversion, and transmits a digital value to the FPGA after the conversion; and the DSP receives FPGA cached data, digitally filters and compresses the cached data, and finally stores the data into the SD card. Due to a dual central processing unit (CPU) structure consisting of the FPGA and the DSP, a large amount of data can be stored and processed; the device has the characteristics of high speed, multiple channels, high resolution and the like; furthermore, pipeline transportation safety is guaranteed; and early maintenance is facilitated.

The invention relates to a giant magnetoresistive effect current sensor using an amorphous alloy magnetic ring structure, and belongs to the technical field of power system measurement. In the current sensor, a wire to be measured passes through an amorphous alloy magnetic ring; and a direct current magnetic biasing coil is wound on the amorphous alloy magnetic ring and is powered by a direct current constant current source. A plurality of layers of giant magnetoresistive effect chips are arranged in an air gap of the amorphous alloy magnetic ring. Positive output ends and negative output ends of the chips are connected with the in-phase input end and the inverted input end of an instrument amplifier respectively; and an output end of the instrument amplifier is connected with an in-phase input end of an operational amplifier. A voltage following resistor is connected in parallel between an inverted input end and an output end of the operational amplifier; the output end of the operational amplifier is connected with an input end of an analog / digital converter; and an output end of the analog / digital converter is connected with a nixie tube display. The current sensor has the advantages of small size, low cost, low energy consumption, wide frequency response, high sensitivity, stabile characteristic and the like, and meets the requirements of environmental friendliness, energy conservation and large-scale distributed monitoring in a novel intelligent power grid.

The invention relates to the technology of cutting force measurement, in particular to an on-line measurement cutter system of the cutting force of an embedded thin film strain gage transducer. The problems that an existing force measurement instrument is large in size, low in measurement precision and sensitivity, complex in structure and high in manufacturing cost are solved. The on-line measurement cutter system of the cutting force of the embedded thin film strain gage transducer comprises a signal collecting part and a signal processing part. The signal collecting part comprises a cutter rod, a blade, a positioning screw, a pressing plate, a fastening bolt, the thin film strain gage transducer, a wiring terminal, a fastening screw and a connecting line. The signal processing part comprises a voltage feedback operational amplifier, an instrumentation amplifier and a PC. The blade is mounted on the left side face of the front portion of the cutter rod in a fastening mode through the positioning screw, and the thin film strain gage transducer is fixedly mounted in the middle of the side face of the cutter rod. The on-line measurement cutter system of the cutting force of the embedded thin film strain gage transducer is suitable for measuring the cutting force in the metal cutting machining process.

This disclosure describes a chopper stabilized instrumentation amplifier. The amplifier is configured to achieve stable measurements at low frequency with very low power consumption. The instrumentation amplifier uses a differential architecture and a mixer amplifier to substantially eliminate noise and offset from an output signal produced by the amplifier. Dynamic limitations, i.e., glitching, that result from chopper stabilization at low power are substantially eliminated through a combination of chopping at low impedance nodes within the mixer amplifier and feedback. The signal path of the amplifier operates as a continuous time system, providing minimal aliasing of noise or external signals entering the signal pathway at the chop frequency or its harmonics. The amplifier can be used in a low power system, such as an implantable medical device, to provide a stable, low-noise output signal.

The invention provides a wide-range broadband current sensor base on a tunnel magnetic resistance effect, and belongs to the field of sensing measurement. The sensor comprises an open magnet ring, current sensing chips, a compensation coil, a sampling resistor, an instrument amplifier, a zeroing circuit, a current output module and a power supply module; the current sensing chips include a high-sensitivity TMR sensing chip and a low-sensitivity TMR sensing chip, and are provided with two current measuring output points; the open magnet ring sleeves a current carrying lead, so that the current carrying lead penetrates through an inner hole of the open magnet ring; the compensation coil is wound around the open magnet ring; the high-sensitivity TMR sensing chip is arranged in an open air gap position of the open magnet ring; the low-sensitivity TMR sensing chip is arranged outside the open magnet ring; the high-sensitivity TMR sensing chip with other composition parts forms a closed loop structure; and the low-sensitivity TMR sensing chip, the instrument amplifier and the zeroing circuit form an open loop structure. The current sensor has the advantages of being wide in measuring range, wide in frequency band, small in size, high in precision, low in cost, free of intrusion and convenient to install and maintain.

Frequency stabilization of chopper-stabilized amplifiers using multipath hybrid double-nested Miller compensation. The compensation may provide a desired 6 dB / oct roll off for both instrumentation amplifiers and operational amplifiers. Various embodiments are disclosed.

Fast-settling capacitive-coupled amplifiers are disclosed. The amplifiers use two Capacitive Coupled paths embedded in a Multipath Hybrid Nested Miller Compensation topology. One path is a direct high frequency path and the other path is a slower stabilization path. This combination results in a flat frequency response to and through the chopper frequency, and a fast settling response. Various exemplary embodiments are disclosed, including operational amplifier and instrumentation amplifier configurations.

An overcurrent detection circuit includes a current detection resistor that generates a voltage in proportion to current flowing through a switching element and a comparator that compares the voltage detected via the current detection resistor and a reference voltage generated by a reference voltage generation circuit to thereby detect overcurrent flowing through the switching element. In particular, the reference voltage generation circuit includes: a first resistance voltage dividing circuit that resistance-divides a standard voltage by connecting, in series, two types of resistors having different temperature characteristics; a second resistance voltage dividing circuit that resistance-divides the standard voltage by connecting, in series, resistors having the same temperature characteristics; and an instrumentation amplifier that generates the reference voltage according to the difference between the divided output voltages of the first and second resistance voltage dividing circuits.

The invention relates to a sensor signal amplifying and conditioning circuit which comprises an instrument amplifier, a same-phase scale amplifier and a voltage follower, wherein the input end of the instrument amplifier is connected with a differential input signal; the voltage follower inputs the reference voltage into the reference voltage end of the instrument amplifier; the output signal of the instrument amplifier is accessed to the same-phase input end of the same-phase scale amplifier; the reverse-phase input end of the same-phase scale amplifier is used as a gain adjusting end; and the output end of the same-phase scale amplifier is used as the output end of the whole sensor signal amplifying and conditioning circuit. The invention is used for amplifying the small differential signal sent by the sensor and converting the differential signal into the single-end signal output to the reference end. By arranging the external resistor, the invention can realize zero-point and gain adjustment, extend the application range, and complete the impedance matching through the voltage follower.

The invention belongs to the technical field of automatic gain control of a radio frequency receiver and specifically relates to a radio frequency power detection circuit. The radio frequency power detection circuit comprises a programmable gain amplifier, a half wave rectifier, an instrumentation amplifier and a six-bit digital to analog converter. The programmable gain amplifier is controlled by two-bit digital logic, a gain step is 3-decibel, and a gain range is 9-decibel; the half wave rectifier is connected with the rear of the programmable gain amplifier, a detection for an input power in a fixed range is completed by the half wave rectifier, and the power range is a working range of the rectifier; signals with different power can be amplified to the working range of a rectifier by an optional gain of an amplifier; and finally the instrumentation amplifier is used for amplifying a direct-current output of the half wave rectifier. The rectifier and the instrumentation amplifier can generate output offset voltages caused by a device mismatch, due to offset direct-current voltages, output voltages of a power detection circuit exceed a measuring range of an analog to digital converter, and a six-bit current type full binary digital to analog converter is used for performing an offset pre-distortion for the circuit.

Low-noise, low-power, low drift offset correction in operational and instrumentation amplifiers and amplifiers using the same are disclosed. The amplifiers disclosed use different combinations of chopping and auto-zero techniques. Also disclosed are amplifiers using on-off switches to affect the chopping and auto-zeroing, with unique circuits for driving the switches on the differential input to provide boot-strapped switch controls. Other features are disclosed.

The invention relates to a high-resolution, wide-measurement range and low-cost digital display temperature detection system and a digital display temperature detection method. The digital display temperature detection system consists of a sensor probe, an analogue voltage signal acquisition circuit, an instrumentation amplifier, an analogue / digital converter, a processor, a drive chip and a digital display. The digital display temperature detection method comprises the following steps of: calling a signal acquisition module to perform voltage value sampling; calling an extreme value eliminating, filtering and averaging module to solve an average value; calling a table searching and temperature value converting module to convert the voltage value into a temperature value; calling a temperature value numerical system conversion module to convert a binary temperature value into a decimal temperature value; and calling a scanning drive module to perform dynamic scanning display. By the system and the method, the resolution of 0.1 DEG C and the measurement range of -15 to +80 DEG C are realized; and the problem that the conventional temperature gauge difficultly balances high resolution, wide measurement range and low cost is solved.

The invention discloses a circuit for detecting dynamic weak capacitance of a micro electro mechanical system (MEMS) device, which is mainly applied to change detection of dynamic weak capacitance in a capacitive MEMS device. The circuit comprises a driving signal generation circuit, a capacitance to voltage (C / V) converting unit, a primary sampling and holding unit, a secondary sampling and holding unit and a signal processing unit. The driving signal generation circuit performs self-oscillation to generate a sine wave signal with fixed amplitude and frequency, and provides a detection pumping signal for the C / V converting unit; the C / V converting unit converts the weak capacitance variation into voltage, and a sine wave signal which can be processed by the subsequent stage of a samplingand holding circuit is output by an instrument amplifier; and the primary sampling and holding unit detects a positive peak point of the input sine wave, and when the positive peak point is detected,the output signal keeps the voltage of the positive peak point and half sine wave cycle is kept unchanged, the latter half cycle changes along with the input signal, and the output signal is used as a signal to be detected of the secondary sampling and holding unit.

The invention discloses a fully differential force balance mode MEMS acceleration sensor signal processing circuit comprising a fully differential switched capacitor circuit, a sampling and holding circuit, an instrument amplifier, a multiphase clock circuit and a reference source circuit. The fully differential switched capacitor circuit detects the MEMS change capacitance and outputs differential signals to be connected with the instrument amplifier through the sampling and holding circuit, and the differential signals are converted into single-end output signals through the instrument amplifier. According to the acceleration sensor signal processing circuit, high-precision and low-noise voltage output can be realized; and the designed acceleration sensor signal processing circuit works in a force balance second-order simulation closed-loop system and can convert the output voltage of the front-end detection circuit into electrostatic force to be fed back to the intermediate pole plate so that the mass block is maintained to vibrate near the balance position, and thus the circuit has high sensitivity.

This invention presents a method and apparatus for measuring the resistance across a fuel cell stack, a fuel cell array, or an individual fuel cell. The invention employs a fixed load circuit to switch a fixed resistance or to connect a fixed load current to the stack or array. When the load is turned on, the stack voltage is read, then the load is turned off and the stack voltage is read again to determine the voltage jump. A change in resistance is calculated that is related to cell hydration. In accordance with another aspect of the invention, the stack includes a programmable DC-DC switch under PWM microprocessor control. The DC-DC converter is used to switch the load on and off and the voltage jump is read using a sample and hold methodology with an optional instrumentation amplifier and a Kalman filter to determine accurate results for resistance with no additional hardware. The resistance measurements are used to identify and evaluate cell hydration.

The invention discloses an underwater data recorder system low in power consumption and belongs to the technical field of underwater sound communication. The data recorder system can collect underwater sound signals and store the signals into a storage module in the data recorder system, can be used in the deep sea environment conveniently and is low in power consumption. The data recorder system specifically comprises an underwater sound signal collecting module, a pre-amplifier, a filter, a pressure sensor, an instrument amplifier, a controller, the storage module and a power source. The underwater sound signal collecting module is used for collecting the underwater sound signals, the collected underwater sound signals are amplified and filtered, then the controller carries out A / D conversion on the underwater sound signals, and the underwater sound signals are written into the storage module through a set format. The pressure sensor is used for collecting pressure data of the working environment of a data recorder so as to obtain the actual depth of underwater working of the data recorder. The system reduces the power consumption of the data recorder by managing the work mode and the work procedure of the data recorder with the lower power consumption, and therefore the data recorder can work independently underwater for a long time.