13 results about "Input offset voltage" patented technology

The invention discloses a foreground calibration circuit for an input offset voltage of an SAR ADC comparator. The foreground calibration circuit comprises a power supply input circuit, an input geminate transistor circuit, a latch comparator, an SAR successive approximation register and a Res DAC resistance voltage division type digital-to-analog converter. The output end of the power input circuit is electrically connected with the power end of the input geminate transistor circuit; an analog input signal VIN and a reference voltage signal VREF are input into the input end of the input geminate transistor circuit, and the output end of the input geminate transistor circuit is electrically connected with two input ends of the latch comparator; the two output ends of the latch comparator are electrically connected with the input end of the SAR successive approximation register, and the output end of the SAR successive approximation register is electrically connected with the input end of the Res DAC resistance voltage division type digital-to-analog converter; the output end of the Res DAC resistance voltage division type digital-to-analog converter outputs a CALIP signal and a CALIN signal to a grid electrode of an adjusting tube in the input geminate transistor circuit, so that the adjusting tube generates compensation current to compensate the current difference of two input geminate transistors in the input geminate transistor circuit, and offset voltage is calibrated.

The invention relates to an audio decoding output stage circuit and audio equipment, the audio decoding output stage circuit comprises an I / V conversion module and a low-pass filtering module, and the I / V conversion module comprises a conversion circuit, a crossed diamond amplification circuit, an overcurrent protection circuit and a Roche network circuit; the conversion circuit comprises a JFET (Junction Field Effect Transistor) audio operational amplifier chip and an I / V (Input / Output) conversion resistor and is used for converting an input current into an analog voltage signal; the crossed diamond amplifying circuit can reduce the input offset voltage; the over-current protection circuit can carry out over-current protection; the rowbell network circuit can prevent high-frequency self-oscillation of the power output stage; and the low-pass filtering module comprises a filtering circuit and an ultrahigh frequency filtering circuit arranged at the output end of the audio decoding output stage circuit. The scheme can bring high-performance sound performance, and has the advantages of lower distortion, higher conversion rate, low output impedance and large pushing current.

This application relates to the field of operational amplifier circuit technology, and more particularly to an inverting operational amplifier circuit for eliminating input offset voltage. It includes an input resistor for receiving an input voltage; an operational amplifier for inverting and amplifying the input voltage; an output resistor section connected in series between the output terminal of the operational amplifier and the input resistor, the output resistor section being composed of multiple output resistors connected in series; multiple current sources connected to nodes between the various output resistors of the output resistor section, the current sources being used to compensate for the output offset voltage caused by the input offset voltage of the operational amplifier; and a digital code input section for adjusting the current values ​​of the current sources; wherein the voltage value of the output offset voltage is determined based on the current values ​​of the multiple current sources and the corresponding resistance values ​​of the output resistor section. Using this application is advantageous for canceling the output offset voltage caused by the input offset voltage of the operational amplifier and appearing at the output terminal.

This invention discloses a bandgap reference circuit structure, belonging to the field of integrated circuit design technology. The circuit structure includes a bandgap reference core circuit, a chopper-equipped operational amplifier (op-amp), a bandgap reference startup circuit, a temperature-to-absolute-temperature (PTAT) bias current source, and a current source startup circuit. By optimizing the bandgap reference core circuit architecture, combining chopper technology to eliminate the effects of offset voltage and device mismatch, and with the matching startup circuit and low-voltage-adaptive bias current source, the reference voltage is essentially independent of the op-amp input offset voltage, improving circuit symmetry performance and load dynamic response speed. Furthermore, in most common complementary metal-oxide-semiconductor (CMOS) processes, it only requires a power supply voltage of 2V or higher to operate stably, significantly improving the accuracy and stability of the reference voltage.

The invention relates to the technical field of analog integrated circuits, in particular to a high-precision temperature sensor temperature-sensing front-end circuit based on a chopping technology, and aims to solve the problems of low-frequency 1 / f noise, operational amplifier input offset voltage drift, band-gap reference temperature drift, limited output driving capability and the like existing at the front end of a traditional temperature sensor. The front-end circuit comprises a chopping band-gap reference source circuit, a chopping buffer circuit and a two-phase non-overlapping clock generation circuit, wherein the chopping band-gap reference source circuit adopts a parasitic bipolar PNP transistor with an emitter junction area ratio of 8: 1 as a temperature sensing device, and a high-gain chopping folded cascode operational amplifier is embedded in the chopping band-gap reference source circuit; and stable positive temperature coefficient voltage and low-temperature drift reference voltage are generated. Noise and maladjustment are inhibited from the system architecture level, the temperature measurement precision can reach the sub-degree centigrade level, the loading capacity is high, the method is achieved based on the standard CMOS technology, a special technology and complex temperature calibration are not needed, and the method has the advantages of being low in cost, high in stability and large-scale integration.

The invention provides an operational amplifier and a chip, and belongs to the technical field of operational amplifiers. The operational amplifier comprises an operational amplification circuit, an offset correction circuit and a control circuit, wherein the control circuit controls the operational amplification circuit and the offset correction circuit to work in a periodic mode. In each working period, the control circuit controls the operational amplifier circuit to generate an output voltage according to the input voltage and the first common-mode voltage; meanwhile, the control circuit controls the offset correction circuit to carry out zero clearing on the offset voltage of the offset correction circuit and carries out zero clearing on the target offset voltage under the action of the output voltage and the second common-mode voltage, and the target offset voltage is a part of the first offset voltage corresponding to the operational amplifier circuit. According to the operational amplifier, loop oscillation can be effectively suppressed and corrected, the output overshoot of the operational amplifier circuit can be remarkably reduced, the residual offset voltage of the operational amplifier circuit can be weakened cycle by cycle, and the input offset voltage of the operational amplifier circuit continuously approaches zero.

This invention provides a low-dropout linear regulator, including a base regulator circuit, a switching unit, and a load. One end of the load is connected to the output terminal of the base regulator circuit, and the other end of the load is connected to load ground. The switching unit is connected to the base regulator circuit. The switching unit is used to store an offset voltage and a reference voltage at a first input terminal of the base regulator circuit, and then swap the functions of the first and second input terminals of the base regulator circuit to cancel the offset voltage at the first input terminal, thereby reducing the impact of the input offset voltage. This invention also provides a control method for the low-dropout linear regulator.

The invention provides a multi-amplifier circuit. The first amplifier (1) amplifies and outputs two input differential voltages. The second amplifier (2) amplifies and outputs the differential voltages of the two inputs. Each of the first amplifier (1) and the second amplifier (2) includes a first differential input circuit (D1), a second differential input circuit (D2), and a current adjustment unit (30). The first differential input circuit (D1) includes a transistor pair that amplifies and outputs a differential voltage of two inputs. The second differential input circuit (D2) includes a transistor pair that amplifies and outputs a differential voltage input to the two differential input circuits (D1). The differential input circuits (D1, D2) have asymmetric structures that each generate input offset voltages that are positively and negatively opposite to each other. A monitor amplifier (51) amplifies and outputs a differential voltage between an input to the first amplifier (1) and an input to the second amplifier (2). The current adjustment unit (30) adjusts the current ratio of the currents flowing into the differential input circuits (D1, D2) in response to the output of the monitor amplifier (51).

A Correlated Double Sampling (CDS) integrating circuit and a data converter, the CDS circuit includes a CDS integration module and a level shifting module. The CDS integration module is configured to sample a first input signal and an Operational Amplifier (Opamp) input offset voltage to a sampling capacitor during a first phase; and sample a second input signal and the Opamp input offset voltage to the sampling capacitor during a second phase, and transfer a charge difference generated on the sampling capacitor to an integrating capacitor. The level shifting module is configured to sample an output signal and a common-mode voltage to a level shifting capacitor during a first stage of the first phase and the second phase, and shift a potential of an Opamp output voltage towards the common-mode voltage through the level shifting capacitor in a second stage of the second phase.

The present disclosure provides a low-noise misalignment calibration comparator and a successive approximation register type analog-to-digital converter, and relates to the technical field of circuits. The circuit comprises a differential input module configured to receive a differential input signal and convert the differential input signal into a differential voltage signal; a latch amplification module having an input end connected to an output end of the differential input module and configured to amplify the differential voltage signal and generate a digital output signal; a misalignment calibration module having an output end connected to a compensation end of the differential input module and configured to dynamically adjust a compensation current to offset an input misalignment voltage of the comparator; and a logic control module having an input end connected to an output end of the latch amplification module and an output end connected to a control end of the misalignment calibration module, and configured to control a working state of the misalignment calibration module bit by bit according to the digital output signal. Through the closed-loop cooperation of the misalignment calibration module and the logic control module, the present disclosure dynamically adjusts the compensation current, effectively offsets the input misalignment voltage of the comparator, and improves the signal decision accuracy.

The application belongs to the field of integrated circuits and analog electronic technology, and particularly relates to an adjustable gain isolated current detection amplifier, which comprises an input module, a programmable gain differential switched capacitor amplifier, an analog-to-digital converter (ADC), a capacitive isolation transmission module, a digital-to-analog converter (DAC) and a filtering and buffering module; the output end of the input module is connected with the input end of the programmable gain differential switched capacitor amplifier, the output end of the programmable gain differential switched capacitor amplifier is connected with the input end of the ADC, the output end of the ADC is connected with the input end of the capacitive isolation transmission module, the output end of the capacitive isolation transmission module is connected with the input end of the DAC, and the output end of the DAC is connected with the input end of the filtering and buffering module; the chopper modulation / demodulation circuit integrated in the switched capacitor amplifier of the application can suppress the input offset voltage and 1 / f noise of the switched capacitor amplifier, and ensure the basic precision of current detection.

An operational amplification device, comprising: an operational amplifier, and a calibration circuit, a first input terminal and a second input terminal of the operational amplifier are shorted; the calibration circuit comprises: a detection circuit, which outputs a detection result based on an output voltage of the operational amplifier; a control circuit, an input terminal of which is coupled with an output terminal of the detection circuit, which outputs a first calibration signal when the detection result is a positive offset voltage, and / or, outputs a second calibration signal when the detection result is a negative offset voltage; and a compensation circuit, which, in response to receiving the first calibration signal, compensates the operational amplifier to reduce the positive offset voltage, and / or, in response to receiving the second calibration signal, compensates the operational amplifier to increase the negative offset voltage. The above scheme eliminates the input offset voltage without affecting the signal-to-noise ratio and bandwidth of the operational amplifier.

This application discloses a circuit and method for adjusting the offset voltage of an operational amplifier. The circuit includes a differential input module with a first input branch and a second input branch, respectively for receiving a non-inverting input signal and an inverting input signal; an input adjustment module connected to both the first and second input branches, used to introduce adjustable adjustment voltages into the first and second input branches to adjust the equivalent input potentials of the first and second input branches; and a bias current generation module for generating a bias current and providing operating current to the input adjustment module. The adjustment voltages introduced by the input adjustment module into the first and second input branches are both formed based on a reference node A. By selecting an adjustment state, the equivalent input potentials of the first and second input branches are made consistent, thereby compensating for the input offset voltage of the operational amplifier.