622results about "Negative-feedback-circuit arrangements" patented technology

Signal processing is applied to a digital input audio signal. An analog audio output signal is provided based on the digital input audio signal via a switching converter circuit driven by a PWM signal. The analog audio output signal is sensed to generate an analog feedback signal. The applied signal processing includes: producing a digital error signal indicative of a difference between the digital input audio signal and a digital word signal; applying digital-to-analog conversion to the digital error signal to produce an analog replica of the digital error signal; producing an analog difference signal indicative of a difference between the analog replica of the digital error signal and the analog feedback signal; applying analog-to-digital conversion to the analog difference signal to produce the digital word signal; applying digital filtering to the digital word signal to produce a filtered digital word signal that generates the PWM signal.

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.

A device includes a signal path including a plurality of inverters connected in series, which comprises a first inverter having a first input and a having first output, a second inverter having a second input coupled to the first output of the first inverter and having a second output, and a third inverter having a third input coupled to the second output of the second inverter and having a third output. The device also includes a first feedback path connecting the second output of the second inverter to the first input of the first inverter, the first feedback path including a fourth inverter and a second feedback path connecting the third output of the third inverter to the second input of the second inverter, the second feedback path including a fifth inverter.

The utility model discloses a detection circuit based on power system transistor driving, which comprises a signal input circuit and a direct current bias circuit, the signal input circuit and the direct current bias circuit are both electrically connected with a differential reduction circuit, the differential reduction circuit is electrically connected with an isolation operational amplifier module, and the isolation operational amplifier module is electrically connected with a differential proportion circuit. The differential proportion circuit is electrically connected with the comparator; the differential proportion circuit and the comparator are electrically connected with an MCU. The direct current bias circuit, the differential reduction circuit, the isolation operational amplifier module, the differential proportion circuit and the MCU are all electrically connected with the DCDC isolation system. The sampling isolation voltage operational amplifier ensures that the system is safe and reliable; single power supply sampling is adopted, the cost is reduced, expansion is facilitated, and the detection cost can be greatly reduced when a system needs to detect driving circuits of multiple transistors at the same time; reference voltage is added to the in-phase end through operational amplifier following, and noise interference is reduced.

The invention discloses a differential closed-loop negative feedback amplification circuit based on JFET geminate transistors, a low-noise amplifier is used for measuring weak voltage signals, discrete JFET field-effect transistors are used for forming an input stage of the low-noise amplifier, noise interference is reduced, meanwhile, extremely high input impedance can be provided by using the characteristic that the grid current of the JFET field-effect transistors is basically zero, and the differential closed-loop negative feedback amplification circuit based on the JFET geminate transistors is obtained. Mirror current is provided for a pair of JFET field effect transistors in the low-noise amplifier module through a current mirror of the low-noise amplifier, a closed-loop feedback structure of the low-noise amplifier can save one path of input for the JFET field effect transistors, so that the amplifying circuit can realize dual-channel input, and a dual-channel input structure can enable an accessed signal to be a differential signal, so that common-mode interference is effectively inhibited, and the reliability of the amplifying circuit is improved. Overall closed-loop negative feedback can achieve high gain stability, reduce nonlinear distortion, increase input impedance, reduce output impedance and improve the performance of the amplifier, and solves the problem of precise amplification and measurement of weak voltage signals in the aviation electromagnetic field.

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.

The invention relates to the technical field of wireless communication, and provides a power amplifier and a radio frequency front-end module, and the power amplifier comprises an input matching circuit, a first-stage amplifier, a second-stage amplifier, an inter-stage matching circuit and a third-stage amplifier which are electrically connected in sequence; the first current unit, the second current unit and the third current unit respectively provide bias current for the input end of the first-stage amplifier, the input end of the second-stage amplifier and the input end of the third-stage amplifier; the first-stage amplifier comprises a first triode, a first resistor, a first capacitor and a first inductor, the base electrode of the first triode serves as the input end of the first-stage amplifier, the emitter electrode of the first triode is connected with the first resistor in series and then grounded, and the collector electrode of the first triode is connected with the first end of the first inductor and the first end of the first capacitor; the second end of the first capacitor serves as the output end of the first-stage amplifier. The power amplifier disclosed by the invention can be used for reducing the output nonlinear noise under the condition of meeting high gain.

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.

An amplifier circuit includes a first operational amplifier (op amp) and a two-terminal synthesis resistor connected across a non-inverting input of the first op amp and an output of the first op amp. The two-terminal synthesis resistor includes a second op amp. The two-terminal synthesis resistor includes a current mirror having a first transistor, a second transistor, and a common node connected to the first transistor, the second transistor, and an output of the second op amp. The two-terminal synthesis resistor includes a resistor having a first side configured to be a first terminal of the two-terminal synthesis resistor, and a second side connected to an inverting input of the second op amp, and the first transistor. The two-terminal synthesis resistor includes a second terminal of the two-terminal synthesis resistor connected to the second transistor, and a non-inverting input of the second op amp.

A biasing circuit for biasing an output transistor in a radio frequency (RF) amplifier includes a first field-effect transistor (FET) monolithically integrated with the output transistor, the first FET being connected to the output transistor in a current mirror configuration, such that a gate-to-source voltage of the first FET is the same as a gate-to-source voltage of the output transistor, and a drain current in the first FET is matched to a drain current in the output transistor and scaled proportionally according to a size of the first FET relative to a size of the output transistor. The biasing circuit further includes a voltage divider integrated with the first FET and connected to a current source, the voltage divider being configured to generate a voltage that is substantially independent of process, voltage and / or temperature variations for controlling the drain current in the first FET.

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.

When a current-to-voltage converter is used at low temperatures, the frequency band of measurable small currents is limited. Stray capacitance of a coaxial cable that takes out an output voltage of the current-to-voltage converter from inside to outside a cooling device narrows the operating frequency band of the current-to-voltage converter. The current-to-voltage converter of the present disclosure uses elements exclusively optimized for low-temperature operation (e.g., HEMTs) as electronic elements for current-to-voltage conversion. This configuration realizes current-to-voltage conversion characteristics with significantly more excellent sensitivity than that of the conventional technique even when the current-to-voltage converter is operated at a low temperature of 150K or less or in cryogenic temperature conditions close to absolute zero. Further, a source follower circuit is added to an output stage of the current-to-voltage conversion circuit to isolate the effect of stray capacitance added to the output side of the current-to-voltage conversion circuit and achieve a wider bandwidth.

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.

An operational amplifier-based hysteresis comparator and a chip are provided. The hysteresis comparator includes: an input stage and an amplification stage. The input stage includes: a first input branch and a second input branch, where the first input branch generates a first current based on the first voltage, and the second input branch generates a second current based on the second voltage. The first current is connected with a first input terminal of the amplification stage, and the second current is connected with a second input terminal of the amplification stage. An output terminal of the amplification stage outputs a first level when the first current is greater than the second current, and outputs a second level when the first current is less than the second current. The present disclosure changes the hysteresis voltage generation mode, thereby reducing the instability caused by positive feedback.

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.