19results about "Positive-feedback-circuit arrangements" patented technology

The invention discloses a high-stability common-mode feedback circuit which is used for accurately adjusting the common-mode level of a differential amplifier. The circuit comprises an amplifying circuit module, a common-mode detection module and a substrate adjusting module, by introducing a substrate adjusting technology, the size of an amplifying tube is reduced, and the stability and bandwidth of common-mode feedback are remarkably improved. Wherein the common-mode detection module adopts a source follower structure and detects common-mode voltage of differential output in real time; the substrate adjusting module can greatly reduce the size of the common-mode adjusting transistor in the common-mode feedback amplifier by adjusting the body port voltage of the common-mode adjusting transistor in the common-mode feedback module and reducing the threshold voltage of the transistor and utilizing the back gate characteristic of the transistor, the parasitic capacitance of the common-mode adjusting transistor is reduced, and the performance of the common-mode feedback amplifier is improved. And meanwhile, the common-mode level stability in a wide input range is realized, and the method is suitable for scenes such as high-speed analog-to-digital converters and low-noise amplifiers which have strict requirements on the common-mode stability.

The invention provides an analog amplifier circuit based on capacitance feedback, which relates to the technical field of signal processing, and comprises a positive voltage local voltage stabilization module, an amplifier module, a bias module and a negative voltage local voltage stabilization module, the positive voltage local voltage stabilization module, the bias module and the negative voltage local voltage stabilization module are all connected with the amplifier module; the positive voltage local voltage stabilization module is used for providing a first stable power supply for the amplifier module; the amplifier module is used for receiving a to-be-amplified signal input externally, performing signal amplification on the to-be-amplified signal to obtain an amplified signal, and outputting the amplified signal; the signal amplification is realized based on a transistor and a feedback capacitor in the amplifier module; the bias module is used for providing first bias voltage for the amplifier module; the negative voltage local voltage stabilization module is used for providing a second stable power supply for the amplifier module. The driving requirement and energy consumption of the amplifier are reduced by adopting capacitance feedback, the energy efficiency of the amplifier circuit is improved, signal amplification is realized through the transistor, and the amplifier circuit with a small area is realized.

The utility model discloses a resistance value measuring circuit for an electromagnetic oil nozzle. The resistance value measuring circuit for the electromagnetic oil nozzle comprises a control chip and an acquisition and measurement circuit, the control chip is provided with two or more PB pin ends and AD pin ends; the collecting and measuring circuit is provided with an electric connecting end, a plurality of oil nozzle connecting ends and an operational amplifier module U1. According to the utility model, the control chip and the acquisition and measurement circuit are arranged, and the acquisition and measurement circuit is provided with two or more PB pin ends and AD pin ends, so that the electromagnetic oil nozzle resistance value measurement circuit is used for carrying out resistance detection on a plurality of electromagnetic oil nozzles, and repeated plugging of the electromagnetic oil nozzles is not needed; the steps are simplified, the detection and measurement efficiency is improved, the connected electromagnetic oil nozzles are controlled to be detected one by one, the consistency is ensured, and the resistance detection precision is improved.

The utility model provides a kind of sensor reference power supply of automobile air conditioner, automobile air conditioner and car, and this sensor reference power supply includes: the positive input pin of operational amplifier is connected with the one end of first resistance, and the other end of first resistance is connected with 5V power supply, the one end of first filter capacitor respectively;The negative input pin of operational amplifier is connected with the one end of second resistance, and the other end of second resistance is connected with the cathode of diode;The positive side power supply pin of operational amplifier is connected with 12V power supply, the one end of second filter capacitor respectively;The output pin of operational amplifier is connected with the one end of third resistance, and the other end of third resistance is connected with the anode of diode, the cathode of diode is connected with the other end of second resistance, the one end of inductance, the other end of inductance is connected with the one end of third filter capacitor.The utility model's scheme can effectively reduce material cost under the premise of not reducing reference power supply precision and reliability, increase market competitiveness for enterprise.

The application discloses a speed threshold device, wherein the speed threshold device comprises a speed acquisition module, a signal amplification module, a frequency-voltage conversion module and a threshold output module; the output end of the speed acquisition module is connected with the input end of the signal amplification module; the signal amplification module receives the output signal of the speed acquisition module and amplifies the output signal; the signal amplification module transmits the amplified signal to the frequency-voltage conversion module; the frequency-voltage conversion module is used for converting the frequency signal into a voltage signal; and the threshold output module is used for controlling the working state of the engine according to the voltage signal output by the frequency-voltage conversion module. The speed threshold device provided by the application adopts digital logic such as signal amplification and frequency-voltage conversion to process the speed threshold, finally realizes the control of the working state of the engine, and avoids the complicated authentication process of using programs to realize the speed threshold control.

This invention relates to a self-biased power amplifier circuit and a self-biased self-resonant power amplifier circuit, belonging to the field of radio frequency circuit technology. In this invention, the source of the power device is connected to a voltage divider module. The internal resistance of the power device and the voltage divider module divide the drain voltage. The voltage obtained across the voltage divider module serves as the source voltage. Since the gate of the power device is grounded, a negative voltage difference is formed between the gate and the source, providing voltage to the source of the power device and achieving self-biasing. Simultaneously, by designing a feedback resonant network composed of a fourth microstrip line, a coupling capacitor, a third microstrip line, an input capacitor, a first microstrip line, and a sixth microstrip line, the DC energy of the drain current is converted into a specific frequency radio frequency signal due to the feedback mechanism, even without an external periodic excitation signal. Part of this signal is coupled through the second and fourth microstrip lines and input to the feedback resonant network; the other part is output through the second microstrip line, the output capacitor, and the fifth microstrip line.

Disclosed in the present invention are a radio frequency power amplifier based on power detection feedback, a chip, and a communication terminal. The radio frequency power amplifier comprises multiple stages of amplifier circuits and at least one power detection feedback circuit; the input end of the power detection feedback circuit is connected to the output end of a current stage of amplifier circuit, and the output end of the power detection feedback circuit is connected to the input ends of the current stage of amplifier circuit and at least one stage of amplifier circuit located prior to the current stage of amplifier circuit. The power detection feedback circuit generates, according to the detected output power of the current stage of amplifier circuit, a control voltage varying inversely with the output power, so that the power detection feedback circuit outputs current varying positively with the control voltage. The quiescent operating current of the current stage of amplifier circuit and at least one stage of amplifier circuit located prior to the current stage of amplifier circuit is controlled by means of the current, so that the radio frequency power amplifier operates in a state in which the gain and the output power are stable.

Radio frequency transmitting and / or receiving integrated circuit comprising at least one radio frequency signal amplifier, said at least one amplifier being configured in operational mode to perform an amplification function of a radio frequency signal applied at the input, said amplifier being configured to perform an oscillator function in a self-test mode of the integrated circuit, to generate a radio frequency signal on at least one of the input or output of said amplifier, characterized in that the integrated circuit is configured to allow, in said self-test mode, the propagation of said radio frequency signal in at least one component of said radio frequency integrated circuit, distinct from said amplifier, and in that it also comprises a circuit for measuring a signal generated following propagation of said radio frequency signal in said component of said integrated circuit and representative of at least one characteristic of said component.Self-testing method for such an integrated circuit.

A transimpedance amplifier system (TIA) for stabilizing high gain and high frequency signals while minimizing parasitic capacitance effects on the transimpedance amplifier system. The TIA includes an operational amplifier having a first input terminal, a second input terminal, and an output terminal. The TIA also includes a signal generating device operatively connected with the first input terminal of the operational amplifier. The TIA also includes a T-network feedback architecture operatively connected with the operational amplifier at the first input terminal of the operational amplifier and the output terminal of the operational amplifier. The T-network feedback architecture has a first impedance network and a second impedance network. The T-network feedback architecture is configured to suppress parasitic capacitance from the transimpedance amplifier system.

The present application belongs to the technical field of analog circuit, and particularly relates to a programmable gain amplifier suitable for a high-precision ADC front end. The programmable gain amplifier of the present application adopts a whole differential structure, and comprises a whole differential amplifier. The amplifier completes the function of signal amplification, and has the characteristics of high gain and high linearity. The switches of the network of the switching feedback resistance and capacitance all adopt transmission gate switches, so as to reduce the channel charge injection effect of the switches and the nonlinearity of the on-resistance of the switches. The feedback network of the programmable gain amplifier changes the size of the feedback resistance and capacitance through the transmission gate and the resistance-capacitance combination, so as to realize the control of the gain. The input signal is amplified by the accurate amplification multiple, and meanwhile the size of the feedback resistance and capacitance is impedance-matched, so as to ensure that the-3dB bandwidth of the whole programmable gain amplifier remains basically unchanged, so that the working speed of the programmable gain amplifier under different gain conditions remains consistent, and the linearity is greatly improved.

Systems and methods that integrate a directional coupling function with directivity that does not have output loss are disclosed. For example, a power amplifier circuit arrangement includes an input terminal to receive an input signal; amplifier circuitry including a first amplifier stage, a second amplifier stage, and a virtual ground node, where an input of the first amplifier stage is coupled to the input terminal, an output of the first amplifier stage is coupled to an input of the second amplifier stage via the virtual ground node, and an output of the second amplifier stage is coupled to the input of the first amplifier stage via feedback circuitry; an output terminal coupled to the output of the second amplifier stage, the output terminal to output an amplified signal; and a directional coupler terminal coupled to the virtual ground node.

The invention discloses a coal mine underground drilling hydrological advanced network monitoring device and method. The device comprises a signal receiving circuit, a receiving control circuit, a monitoring calculation circuit and a signal transmission circuit. The signal receiving circuit is used for receiving electric signals according to set parameters and transmitting the received electric signals to the receiving control circuit, and the receiving control circuit preliminarily processes the received signals, controls operation of the whole circuit, guarantees transmission of the signals and transmits the preliminarily processed signals to the monitoring calculation circuit. The monitoring calculation circuit further conditions the received signal and transmits the conditioned signal to the signal transmission circuit, and the signal transmission circuit modulates the signal and then transmits the signal in an electric field mode. According to the invention, the drilling hydrological parameter condition can be monitored in real time, the accuracy of monitoring data can be ensured, and the anti-interference capability and the sensitivity of the received signal are improved, so that the development and the application of an underground coal mine exploration technology are promoted.

The application provides a fourth-order feedforward compensation operational amplifier and a design method thereof, and is based on a structural design of "mainly taking a fourth-order operational amplifier path, and sequentially feeding forward compensation from a higher first order to a lower first order in adjacent two-order operational amplifier paths", so that a gain and three zero points of a transfer function can be easily obtained, only a feedforward branch exists, no feedback branch exists, four poles can be obtained by node parameters, and a transfer function of the fourth-order feedforward compensation operational amplifier can be obtained according to the obtained direct current gain, the three zero points and the four poles, that is, the transfer function can be easily obtained based on the circuit structural design; based on the obtained transfer function and a gain requirement of a continuous-time band-pass sigma-delta modulator, a transconductance constraint relationship between each transconductance amplification unit can be deduced, each transconductance amplification unit is selected and designed according to the corresponding transconductance constraint relationship, and the formed fourth-order feedforward compensation operational amplifier can effectively meet the use requirement of the continuous-time band-pass sigma-delta modulator.

Reducing a spring softening effect on a capacitive sense element of an electromechanical sensor is presented herein. A system, such as a microphone or an accelerometer, comprises an electromechanical sensor and a voltage-to-voltage converter component. The electromechanical sensor comprises a capacitive sense element and a bias voltage component that applies a bias voltage to a sense electrode of the capacitive sense element. The voltage-to-voltage converter component couples a positive feedback voltage to the sense electrode to maintain a constant charge at the sense electrode to facilitate a reduction of charge flow in the electromechanical sensor representing a spring softening effect on the capacitive sense element. In an example, the spring softening effect on the sense element alters a resonant frequency of the sense element and a gain of the sense element. In another example, the charge flow corresponds to a parasitic capacitance that is electrically coupled to the sense electrode.

An electronic device may be provided with wireless circuitry that includes a transceiver. The transceiver may include a first signal path and a second signal path extending parallel to the first signal path. The first signal path may include a first chain of gain stages and a first inductive matching network. The second signal path may include a second chain of gain stages and a second inductive matching network. The first inductive matching network may be magnetically coupled to the second inductive matching network. The first and / or second signal path may include one or more crossovers that invert a polarity of the signals on the signal paths. The crossovers may help to mitigate the effects of the magnetic coupling between the first and second signal paths while allowing for minimal spatial separation between the signal paths.

The invention discloses a self-bias power amplification circuit and a self-resonance power amplification circuit based on self-bias, and belongs to the technical field of radio frequency circuits. The source electrode of the power device is connected with the voltage dividing module, the internal resistor of the power device and the voltage dividing module divide the voltage of the drain electrode, the voltage divided at the two ends of the voltage dividing module serves as the voltage of the source electrode, the grid electrode of the power device is grounded, negative voltage difference is formed between the grid electrode and the source electrode, the voltage is provided for the source electrode of the power device, and self-biasing is achieved. Meanwhile, by designing a feedback resonance network composed of a fourth microstrip line, a coupling capacitor, a third microstrip line, an input capacitor, a first microstrip line and a sixth microstrip line, under the condition that no external periodic excitation signal exists, direct-current energy of drain current is converted into a radio-frequency signal with a specific frequency due to a feedback mechanism, and the radio-frequency signal is converted into a radio-frequency signal with a specific frequency. One part is coupled with the fourth microstrip line through the second microstrip line and then serves as an input signal to be input to the feedback resonance network, and the other part is output through the second microstrip line, the output capacitor and the fifth microstrip line.

An amplifier circuit and a method for reducing output voltage overshoot in an amplifier circuit are disclosed. The amplifier circuit includes an amplifier and an output transistor. The amplifier circuit is coupled to an output node of the output transistor to provide an output voltage to a load device. The amplifier circuit also includes a slew rate control circuit coupled to a gate node of the output transistor and configured to control a voltage rise of the gate node of the output transistor during power up to reduce output voltage overshoot.

The invention discloses a decision feedback circuit for a receiving end of a high-speed serial circuit, the circuit comprises an even path structure and an odd path structure which have the same structure, and the even / odd path structure comprises an adder, a first slicer, a second slicer, a multiplexer, a first D flip-flop, a second D flip-flop, a third D flip-flop and a fourth D flip-flop; the output end of the first D trigger in the even path structure is connected with the control end of the multiplexer in the odd path structure; and the output end of the first D trigger in the odd path structure is also connected with the control end of the multiplexer in the even path structure. In addition, the output ends of the triggers in many odd-even paths are connected with the input end of the summator. Under the high-speed scene, the feedback signal loop margin can be met, and meanwhile the requirement for the clock rate is lowered.