450results about "Negative-feedback-circuit arrangements" patented technology

An amplifier circuit including a first amplifier having a first amplifier input and a first amplifier output and a transformer including a first transformer component having a first primary winding in series with the first amplifier output and a first secondary winding coupled to the first amplifier input. The first primary winding and the first secondary winding are arranged such that a portion of a first magnetic field generated by the first primary winding couples to the first secondary winding through a first magnetically coupled feedback loop. The transformer further includes a second transformer component having a second primary winding in series with an output of a second amplifier and a second secondary winding coupled to an input of the second amplifier input. A portion of a second magnetic field generated by the second primary winding couples to the second secondary winding through a second magnetically coupled feedback loop.

A system and method are used to maintain a variance in feedback factors of an amplifier between the first and second phases either below a threshold value or within a specified range. The system includes the amplifier and first through third capacitances. The amplifier is coupled between an input node and an output node that operates during first and second phases of operation. The first capacitance is coupled across the amplifier and between the input node and the output node during the first and second phases of operation. The second capacitance is coupled to the input node during the first phase of operation. The third capacitance is coupled to one of the input and output nodes during one or both of the first and second phases of operation.

Front end systems and related devices, integrated circuits, modules, and methods are disclosed. One such front end system includes a low noise amplifier in a receive path and a multi-mode power amplifier circuit in a transmit path. The low noise amplifier includes a first inductor, an amplification circuit, and a second inductor magnetically coupled to the first inductor to provide negative feedback to linearize the low noise amplifier. The multi-mode power amplifier circuit includes a stacked output stage including a transistor stack of two or more transistors. The multi-mode power amplifier circuit also includes a bias circuit configured to control a bias of at least one transistor of the transistor stack based on a mode of the multi-mode power amplifier circuit. Other embodiments of front end systems are disclosed, along with related devices, integrated circuits, modules, methods, and components thereof.

The invention discloses a multi-channel common-mode feedback high-gain amplification circuit. The circuit comprises a differential amplification module, an output end of which is connected with a load; the input end of the common-mode detection module is connected with the output end of the differential amplification module; the first input end of the error amplification module is connected with the output end of the common-mode detection module, and the second input end of the error amplification module receives reference voltage; and the multi-path feedback control module comprises at least two feedback branches which are connected in parallel, the input ends of the feedback branches are jointly connected with the output end of the error amplification module, the output ends of the feedback branches are respectively connected with different bias nodes in the differential amplification module, and the feedback branches have path impedance with gradient change. Through a dynamic division mechanism of a feedback branch, and in combination with a gain boosting unit and a hybrid compensation network, high-precision rapid establishment under a high-speed load is realized.

Front end systems and related devices, integrated circuits, modules, and methods are disclosed. One such front end system includes a low noise amplifier in a receive path and a multi-mode power amplifier circuit in a transmit path. The low noise amplifier includes a first inductor, an amplification circuit, and a second inductor magnetically coupled to the first inductor to provide negative feedback to linearize the low noise amplifier. The multi-mode power amplifier circuit includes a stacked output stage including a transistor stack of two or more transistors. The multi-mode power amplifier circuit also includes a bias circuit configured to control a bias of at least one transistor of the transistor stack based on a mode of the multi-mode power amplifier circuit. Other embodiments of front end systems are disclosed, along with related devices, integrated circuits, modules, methods, and components thereof.

A voltage generation circuit includes a voltage input terminal, a voltage output terminal, a first resistor having a first terminal electrically connected to the voltage input terminal, a second resistor having a third terminal electrically connected to the second terminal and a fourth terminal electrically connected to a ground potential, a first capacitor having a first capacitive terminal electrically connected to the voltage input terminal, a third resistor having a fifth terminal electrically connected to a second capacitive terminal, a fourth resistor having a seventh terminal electrically connected to a sixth terminal, and a first operational amplifier having a first inverting input terminal electrically connected to the sixth terminal, a first non-inverting input terminal electrically connected to the second terminal, and a first output terminal electrically connected to the voltage output terminal and an eighth terminal.

The invention discloses a high-linearity and high-power GaAs HBT (Heterojunction Bipolar Transistor) power amplifier with a power detection function. The high-linearity and high-power GaAs HBT power amplifier comprises a radio frequency path, a bias module and a power detection circuit, the radio frequency path is used for performing power amplification on a radio frequency signal, improving the stability and expanding the bandwidth by using a negative feedback network, and improving the overall linearity by second harmonic suppression; the bias circuit is used for providing bias voltage dynamically changing along with input power for the three-stage amplification circuit, so that the problems of linearity deterioration and current instability caused by a self-heating effect under high-power input of the GaAs HBT transistor are solved, and amplitude-amplitude distortion and amplitude-phase distortion of the power amplifier are improved; and the power detection circuit is used for outputting a direct-current voltage which is positively correlated with the output power so as to realize accurate control on the output power of the power amplifier. According to the invention, negative feedback, dynamic bias and harmonic suppression technologies are fully combined, and the overall linearity of the amplifier is effectively improved.

Circuits and methods for providing ESD protection, particularly for LNAs lacking a DC blocking input capacitor (“capless LNAs”). Novel circuitry provides both improved ESD protection and an improved Noise Figure compared to conventional designs. One embodiment includes an integrated circuit including a voltage source pin and a plurality of low-noise amplifiers lacking a respective DC blocking input capacitor, each of the plurality of low-noise amplifiers including: a voltage source terminal coupled to the voltage source pin, an input terminal configured to receive a signal to be amplified, an output terminal configured to output an amplified version of the received signal to be amplified, an ESD protection circuit coupled to the input terminal and to both the voltage source terminal and a reference potential, and a distributed ESD clamp coupled between the reference potential and a node located between the ESD protection circuit and the voltage source terminal.

The utility model relates to the technical field of satellite navigation, in particular to a satellite navigation anti-interference signal intensifier, which comprises a receiving antenna, a prefilter, a fixed amplification module and an automatic gain module which are sequentially connected, the output end of the fixed amplification module is further connected with a control module, and the control module comprises a peak value detection unit and a switch control unit. Two output ends of the switch control unit are connected with a control end of the automatic gain module, the peak detection unit is used for detecting a signal peak value, and the switch control unit controls the amplification factor of the automatic gain module based on the signal peak value output by the peak detection unit. According to the utility model, the prefilter is used for filtering interference signals, then the peak value detection unit is used for judging the magnitude of the signals, and then the switch control unit is used for selecting different resistors, so that the amplification factor of the automatic gain module is changed, the signals are enhanced, the final signals are in a proper range, subsequent signal processing is facilitated, and the practicability is higher.

The invention belongs to the technical field of integrated circuits, and particularly discloses a numerical control programmable gain amplifier chip, which adopts an SIP (Session Initiation Protocol) packaged operational amplifier, a digital potentiometer, an input end Vin and an output end Vout, and is characterized in that an alternating current signal is input from the Vin end and is connected to an inverted input end of the operational amplifier through a capacitor C1 and an input resistor R1; a positive power supply pin of the operational amplifier is connected with a power supply positive electrode VDD, a negative power supply pin is grounded, and a VDD / 2 direct current bias voltage is obtained by an in-phase input end through a precision resistance voltage dividing network and is accessed after low-pass filtering; the high end of the digital potentiometer is connected with the Vout end, the low end is connected with the inverting input end of the operational amplifier, and a feedback path is formed through a sliding end. The digital potentiometer and the operational amplifier are integrated, high integration and modularization of the programmable gain amplification circuit are achieved, and the problems that in a traditional discrete scheme, due to analog switch conduction resistance, gain precision is insufficient, reliability of a multi-element system is lowered, and the circuit size is large are solved.

A weak light signal data acquisition system for a laser confocal eyelid microscope comprises a photoelectric signal conversion amplification module, a data acquisition module, an upper computer program module and a signal modulation processing module. The photoelectric signal conversion and amplification module captures weak light signals with the wavelength of 200-900 nm through a high-sensitivity photoelectric detector, converts the weak light signals into electric signals and then amplifies the electric signals through a cross-group amplifier, so that the integrity and stability of the signals are ensured. The signal modulation circuit further improves the signal-to-noise ratio through an operational amplifier and an RC filter network, and eliminates the noise of a high-frequency system through the design of a wave trap. The data acquisition module acquires voltage signals, and the upper computer program module controls the data acquisition process in real time through graphical programming. And the signal modulation processing module filters, fits and arranges the digital signals, and optimizes the imaging quality. According to the system design, the definition and accuracy of laser confocal microscope imaging are effectively improved, and the requirement of ophthalmology medical high-precision imaging is met.

The invention belongs to the technical field of integrated circuit signal processing, and discloses a temperature compensation circuit for a logarithmic detector and the logarithmic detector thereof, and the temperature compensation circuit for the logarithmic detector comprises a first temperature compensation module, a second temperature compensation module and a third temperature compensation module. The first temperature compensation module is used for performing temperature compensation on the current summation module, the second temperature compensation module is used for performing temperature compensation on bias voltage and current of the limiting amplifier module, and the third temperature compensation module is used for performing temperature compensation on bias voltage and current of the rectifier module. The logarithmic detector temperature compensation circuit is suitable for performing temperature compensation on the current summation module, the limiting amplifier module and the rectifier module of the logarithmic detector, and the output precision and consistency of the logarithmic detector are improved.

The invention discloses a high-linearity low-noise amplifier based on harmonic suppression, relates to the field of communication and the technical field of electronic devices, and is used for solving the problem that the noise coefficient of an existing Darlington structure is large. Comprising a noise matching and input matching network, a linearity enhancement structure, a negative feedback structure and a pre-distortion structure. Wherein the linearity enhancement structure at least comprises a first amplification transistor and a second amplification transistor which are arranged in parallel, and is used for improving the linearity of the circuit through harmonic cancellation; the negative feedback structure is connected with the noise matching and input matching network and the pre-distortion structure and is used for expanding circuit bandwidth and optimizing output matching; the pre-distortion structure is used for stabilizing the bias voltage of the third amplification transistor. According to the invention, the linearity of the whole circuit is effectively improved, and the source microstrip lines of the two circuits are utilized to improve the minimum noise matching and improve the noise performance. Noise is reduced, linearity is improved, low-frequency gain is suppressed, and bandwidth of the whole circuit is improved.

Provided is a buffer circuit that can realize a wide dynamic range, a reduced area, and a reduced power consumption amount while maintaining low output impedance. The buffer circuit includes a first transistor, a current source, a second transistor, an output terminal, and first and second capacitors. The first transistor has a gate to which an input signal is input. The current source is connected to one terminal of the first transistor. The second transistor is connected to the other terminal of the first transistor. The output terminal is connected to the one terminal or the other terminal of the first transistor. The first and second capacitors are between the current source and the gate of the second transistor. The first transistor, the second transistor, and the first capacitor form a first feedback circuit. The first transistor, the current source, and the second capacitor form a second feedback circuit.

Provided are an audio playing module and an audio processing circuit thereof, and an electronic device, which belong to the technical field of electronics. In the audio processing circuit, by adding a feedback control circuit between a power circuit and an audio amplifier, the feedback control circuit can control, according to a change in the amplitude of an audio signal received by the audio amplifier, the power circuit to adjust a power supply voltage provided for the audio amplifier. Thus, when the amplitude of the audio signal changes, an appropriate power supply voltage can be matched for the audio amplifier by means of the feedback control circuit, thereby solving the problem of the audio playing module generating whistling when the amplitude of the audio signal changes, and thus optimizing the sound quality of played sounds.

A novel differential amplifier with a feedforward bias correction circuit, and a device. Common-mode voltage output of a differential amplifier is dynamically adjusted based on an input voltage by using a bias correction circuit. This can greatly reduce an input voltage error of the differential amplifier caused by an offset of the common-mode voltage output, so that a quite small input signal can be detected at high precision, assisting a common-mode regulation channel in tracking the common-mode voltage output, thereby reducing the offset of the common-mode voltage output and improving accuracy of the differential amplifier.

The invention relates to a buffer and an integrated circuit. The buffer includes: an operational amplifier; the first end of the voltage-voltage feedback network is coupled to the positive phase / negative phase input end of the operational amplifier; the first end of the isolation resistor is coupled to the output end of the buffer; the first group of switches and the second group of switches are controlled to be closed when the first capacitive load is driven, the second group of switches are disconnected when the second capacitive load is driven, and the first group of switches are disconnected and the second group of switches are closed when the second capacitive load is driven; in the first load, the output end of the operational amplifier is coupled to the output end of the buffer through at least one switch in the first group of switches, and the second end of the voltage-voltage feedback network is coupled to the output end of the buffer through at least one switch in the first group of switches. In the second load, the output end of the operational amplifier is coupled to the second end of the isolation resistor through at least one switch in the second group of switches, and the second end of the voltage-voltage feedback network is coupled to the output end of the operational amplifier through at least one switch in the second group of switches.

The invention relates to an inductance type position sensor, which comprises a micro-control unit, a rotor and a stator, and further comprises a signal amplification circuit used for amplifying an induction signal which is a differential signal; the low-frequency filtering circuit is used for receiving the amplified induction signal and carrying out high-pass filtering or band-pass filtering on the induction signal so as to filter a low-frequency signal; the demodulation circuit is used for receiving the induction signal filtered by the low-frequency filtering circuit and demodulating the induction signal into a low-frequency demodulation signal; the high-frequency filtering circuit is used for receiving the demodulation signal and carrying out low-pass filtering on the demodulation signal so as to filter a high-frequency signal; the micro-control unit receives the demodulation signal filtered by the high-frequency filtering circuit so as to convert the demodulation signal into position information.

The invention provides an error amplifier for peak current mode control and a converter system. The error amplifier comprises a transconductance amplifier, a voltage clamping module, a voltage-current converter, a slope compensation module, a current clamping module and a mirror image tube, the negative end of the transconductance amplifier is used for loading feedback voltage, and the positive end is used for loading reference voltage; the output end of the transconductance amplifier, the output end of the voltage clamping module and the input end of the voltage-current converter are electrically connected; the voltage-current converter generates error current; the slope compensation module is used for performing slope compensation on the error current to generate a compensated current; the output end of the slope compensation module, the output end of the current clamping module and the positive end of the high-side comparator are electrically connected with a second reference node; and the mirror image tube is used for loading the comparison voltage to the positive end of the high-side comparator. The error amplifier provided by the invention can realize more stable mode switching and more accurate current limiting control.

The invention discloses a switched capacitor circuit, a signal receiving chip and an Ethernet transceiver. The switched capacitor circuit comprises a first group of capacitors, a second group of capacitors, a third group of capacitors, a fully differential operational amplifier and a switch assembly. According to the technical scheme, on one hand, the switched capacitor circuit is controlled under the external clock signal to achieve the alternating process of the sampling phase state and the amplification phase state, a negative feedback loop is formed in the amplification phase state, and the frequency response and amplitude balance of the signal are ensured through the negative feedback loop. And on the other hand, compared with a traditional linear equalizer, the transfer function of the switched capacitor circuit in the technical scheme is only related to the capacitance ratio theoretically and is not easily influenced by process deviation, power supply voltage or temperature change, so that stable equalization frequency range and equalization strength are achieved, the stability of equalization capability is ensured, and the service life of the equalizer is prolonged. And the method is applied to an Ethernet receiving channel to omit CTLE, so that the structural design can be simplified.

The invention relates to the technical field of charge amplification, and discloses a charge amplification device and electronic equipment, and the charge amplification device comprises an input connection end which is used for connecting a signal source; an output connection; the input end of the integral amplification circuit is connected with the input connecting end, the output end of the integral amplification circuit is connected with the output connecting end, and the integral amplification circuit is used for carrying out integral processing on a current signal input by the signal source and outputting a voltage signal. A capacitance feedback loop of the integral amplification circuit is connected with a feedback capacitance network composed of a plurality of capacitors. The capacitance feedback loop of the integral amplification circuit in the charge amplification device adopts a feedback capacitance network as an equivalent feedback capacitor, the amplification gain of the charge amplification device is improved by more than two orders of magnitude, and the measurement sensitivity is greatly improved.

The utility model relates to the technical field of radio frequency and microwave, in particular to a linearization circuit of a power amplifier, which comprises the power amplifier used for amplifying an input signal and providing required output power; the bias circuit is used for providing bias voltage for the power amplifier and controlling the change characteristic of a quiescent operating point of the power amplifier along with the temperature and the power; the active feedback circuit comprises a first connection point P1, a second connection point P2 and a third connection point P3, the active feedback circuit effectively reduces nonlinear distortion of the power amplifier through a negative feedback mechanism, and the nonlinear distortion of the power amplifier is effectively reduced by adjusting a first resistor R5, a second resistor R4, a third resistor R1 and a fourth resistor R3. The feedback circuit can be controlled to work in a critical region of a saturation region and a linear region, so that the linearity of the power amplifier can be optimized.

The utility model relates to the technical field of electronics, in particular to a sensor signal processing circuit and a signal processing device. The signal processing circuit comprises a signal amplification circuit, a filter circuit, an analog-to-digital conversion circuit and a power supply circuit. The input end of the signal amplification circuit is used for receiving a sensor, the output end of the signal amplification circuit is connected with the input end of the filter circuit, and the output end of the filter circuit is connected with the input end of the analog-to-digital conversion circuit; the output end of the power supply circuit is connected with power supply terminals of the signal amplification circuit, the filter circuit and the analog-to-digital conversion circuit. Firstly, a signal amplification circuit is adopted to amplify an analog voltage signal output by an ultrasonic sensor, then a filter circuit is adopted to filter the amplified analog voltage signal, and finally an analog-to-digital conversion circuit is adopted to convert the filtered analog signal into a digital signal which can be directly read by a microprocessor. And the application scene of the ultrasonic sensor is expanded.

The invention relates to an amplifier circuit (1) for broadband and low-noise amplification of a capacitive current source, preferably a thermoelectric sensor, comprising: a signal input (3) which can be connected to the capacitive current source in a node K1; the invention relates to an amplifier (1) for amplifying an input voltage, comprising an input stage (A1), which is connected to a node K1 at an input (7) of the input stage (A1) and has a node K2 at an output (9) of the input stage (A1), the input stage (A1) being designed to amplify the input voltage by at least three times, the input stage (A1) being designed to provide a high-ohm input resistance at the input of the input stage (A1), the input stage (A1) is designed to provide a stable and load-independent voltage at the output of the input stage (A1); the invention relates to a power amplifier comprising a first amplifier (A1) and a second amplifier (A3), an amplifier cascade (11) having at least a first amplifier and a second amplifier (A2, A3), each having an input (13, 17) and an output (15, 19), the output (15) of the first amplifier (A2) being connected in a node K3 to the input (17) of the second amplifier (A3), the input (13) of the first amplifier (A2) being connected to a node K2, the output (15, 19) being connected in a node K3 to the input (17) of the second amplifier (A3). An output (19) of the second amplifier (A3) is connected to a node K4, the amplifier cascade (11) being arranged to produce a high signal gain with a low phase shift over a wide frequency range; a feedback network (F1), which is connected to the input (7) of the input stage (A1) in a node K1 and to the output (19) of the second amplifier (A3) in a node K4, said feedback network (F1) being designed to provide a high-ohm feedback resistance with a parasitic capacitance of less than 0.5 pF, the feedback network (F1) is arranged to provide a negative feedback to a structure comprising the input stage (A1) and the amplifier cascade (11), and a signal output (21) connected to a node K5, which is connected to or corresponds to a node K4. The invention also relates to a sensor system.

The invention relates to the technical field of guide rail meter testing, in particular to a proportional operational amplifier circuit for simulating Rogowski coil signal output and a testing device, which comprises a current sampling loop for converting input current into voltage analog signal output, and a proportional amplification loop connected with the output end of the current sampling loop, and the analog module is used for amplifying an input voltage analog signal by an amplification coefficient K and then outputting the amplified voltage analog signal, and the amplification coefficient K is matched with the sensitivity coefficient S of the Rogowski coil to be simulated. Through the collaborative design of the high-precision current transformer and the proportional operational amplifier circuit, the primary side test current is reduced to below 50A, and meanwhile, a voltage signal which is equal to a Rogowski coil in proportion is accurately generated through the proportional operational amplifier circuit. According to the design scheme, the final test effect can be achieved by applying the current of 0.04-50A, the test environment is safer compared with the test environment with the large current of 500A, and the service life of the test bench body is protected.

The invention relates to the field of digital amplifiers, in particular to a system and method for improving feedback and stability in digital amplifiers. The system comprises a signal acquisition module, a feedback signal processing module, an adaptive adjustment module, a comparison and control module and a digital amplifier main body module, the signal acquisition module accurately acquires an output signal; the feedback signal processing module filters and amplifies output information and compensates delay, amplitude attenuation and environmental factors; the adaptive adjustment module adjusts equipment feedback parameters in real time through a fuzzy control algorithm and a neural network model; the comparison and control module adjusts the input signal according to the error signal, and the digital amplifier body outputs the amplified signal. The invention not only can greatly improve the precision of feedback signals and enhance the stability of the amplifier under various working conditions, but also can effectively improve the quality of transmission signals, reduce distortion and noise, improve the reliability of the system and prolong the service life of the system, and has a good application prospect.

A signal processing device comprises an amplifier, a first switch assembly, a second switch assembly and a microcontroller. The first switch assembly is configured to receive a first signal; the second switch assembly is configured to receive a second signal; when the microcontroller is configured to turn on the first switch assembly, the first switch assembly is configured to transmit the first signal to the amplifier; when the microcontroller is configured to turn on the second switch assembly, the second switch assembly is configured to transmit the second signal to the amplifier.

In an embodiment, a method includes connecting a first subset of a set of stages of a power amplifier to a supply voltage, connecting a second subset of the set of stages to a reference voltage different than the supply voltage, switching a third subset of the set of stages according to a switching frequency, assigning numbers of stages in the first subset, the second subset, and the third subset based on a power requirement of the power amplifier, and amplifying a transmit signal using the first subset, the second subset, and the third subset to generate an amplified transmit signal.

An amplifier device may include a signal input for receiving a reference signal and amplifier circuitry. The amplifier device has a feed-forward signal path providing a feed-forward signal. First signal combining circuitry is configured to generate an error signal representative of a difference between the reference signal and a signal proportional to an amplified signal. Signal processing circuitry is configured to process the error signal to obtain a first signal. Second signal combining circuitry is configured to combine the first signal and the feed-forward signal to obtain a combined signal which is applied to an input of the amplifier circuitry. The signal processing circuitry has a limiter coupled to a loop filter. The limiter is configured to limit an amplitude of a second signal to a predetermined value thereby obtaining a limited signal. The loop filter is configured to obtain the first signal based on the limited signal.

An acoustic apparatus includes a class-D amplifier including a current feedback circuit, and a speaker system including a voice coil driven by the class-D amplifier. The speaker system is configured such that, in a case where the speaker system is driven by an ordinary amplifier having a first output resistance lower than a second output impedance of the class-D amplifier, a Q factor of the speaker system falls below a predetermined lower limit of an ordinary Q factor range of an ordinary speaker system. The current feedback circuit is configured to increase the second output impedance of the class-D amplifier by feeding a current flowing to the voice coil back to an input of the class-D amplifier so as to increase a Q factor as the acoustic apparatus higher than the predetermined lower limit of the ordinary Q factor range and within the ordinary Q factor range.