36 results about "Input offset voltage" patented technology

The invention discloses a low-output-ripple ultralow-offset-voltage operational amplifier and a working method thereof. The low-output-ripple ultralow-offset-voltage operational amplifier comprises a first chopper circuit, a first-stage operational amplifier additionally provided with an offset voltage adjusting circuit, a second chopper circuit, a notch filter, a second-stage operational amplifier and a third-stage operational amplifier which are sequentially connected. The offset voltage adjusting circuit trims the input offset voltage of the first-stage operational amplifier to hundreds of microvolts and then outputs the offset voltage to the second chopper circuit; the first chopper circuit and the second chopper circuit are used for modulating the offset voltage of the first-stage operational amplifier to a chopping frequency, and then the ripple voltage at the chopping frequency is filtered by the notch filter; the first-stage operational amplifier is designed to be a high-gain amplifier so as to restrain input offset voltage errors caused by the second-stage operational amplifier and the third-stage operational amplifier. According to the invention, low output ripple voltage and ultralow input offset voltage can be realized only by using the wave trap with a small area.

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 present invention discloses a memristor simulator equivalent circuit, control method and electronic device, belonging to the technical field of circuit element simulators. The memristor simulator equivalent circuit provided by the present invention utilizes a combination of a multiplier and an operational amplifier to reproduce the characteristics of a memristor and replace the memristor for use. It not only supports long-term debugging and use, but also avoids the use of complex hardware circuit design and high device costs, and solves the problem of performance degradation under non-ideal conditions. By introducing an integrator composed of a second operational amplifier and an integrating capacitor, the dynamic characteristics of the memristor can be accurately simulated, ensuring the stability of the conductivity in the non-conducting state and reducing errors caused by the non-ideal characteristics of the operational amplifier (such as input offset voltage and input bias current); by providing a single-pole double-throw switch, the circuit can be flexibly switched between different operating modes, making it easy to adjust the circuit parameters according to actual application requirements, thereby optimizing the simulator performance.

The invention relates to the technical field of operational amplification circuits, in particular to an inverted operational amplification circuit for eliminating input offset voltage. The input resistor is used for receiving an input voltage; the operational amplifier is used for outputting the input voltage after inverting amplification; the output resistor part is connected between the output end of the operational amplifier and the input resistor in series, and the output resistor part is formed by connecting a plurality of output resistors in series; a plurality of current sources respectively connected to nodes between output resistors of the output resistor unit, the current sources compensating an output offset voltage caused by an input offset voltage of the operational amplifier; the digital code input part is used for adjusting the current value of the current source; wherein the voltage value of the output offset voltage is determined according to the respective current values of the plurality of current sources and the resistance value corresponding to the output resistance part. According to the invention, the offset of the output offset voltage caused by the input offset voltage of the operational amplifier and appearing at the output end is facilitated.

The invention provides a current proportion mirror image circuit and an electronic product. The current proportion mirror image circuit comprises a current mirror module composed of a first transistor, a second transistor, a third transistor, a first capacitor, an operational amplifier and a mode switching unit; wherein the first ends of the first and second transistors are connected with working voltage, the control ends are connected with driving voltage, and the second end of the third transistor is connected with a CS end; the mode switching unit is used for switching an input signal of the operational amplifier and a control end signal of the third transistor based on different working modes; the second end of the third transistor outputs detection current having a preset proportion with the load current, and the second end of the second transistor is connected with a load; and the offset compensation module is used for sampling and compensating the input offset voltage of the operational amplifier. The offset compensation module is constructed by utilizing a self-zero-setting technology, so that the input offset voltage of the operational amplifier in the current mirror module is reduced, and the detection precision of the current proportion mirror circuit is improved.

To provide an input circuit that can reduce an input offset voltage while suppressing a change in response of a semiconductor device, and a semiconductor device comprising such an input circuit.SOLUTION: An input circuit has a first differential transistor portion having a plurality of first transistors connected in parallel to each other, a second differential transistor portion having a plurality of second transistors connected in parallel to each other, and a cutoff selectable portion. An output circuit has a first current path portion and a second current path portion disposed in parallel to each other. A first terminal of each of the plurality of first transistors is connected to the first current path portion. A first terminal of each of the plurality of second transistors is connected to the second current path portion. The cutoff selectable portion is connected in series to at least one transistor among the plurality of first transistors and the plurality of second transistors. The cutoff selectable portion is selected to be in one of a state that allows a current to flow and a state that cuts off the current.SELECTED DRAWING: Figure 1

The present invention relates to a low-voltage operational amplifier for reducing system offset voltage, comprising a folded cascode input module (101), a CLASS_AB output stage control circuit (102), and an output stage module (103). The low-voltage operational amplifier solves the problems of large system offset voltage, inaccurate output stage quiescent current control, and wasted dynamic power consumption in existing low-voltage CLASS_AB operational amplifiers, improves the output stage quiescent current error caused by the channel length modulation effect, and simultaneously improves the current matching of the first stage cascode tube by adding a second stage cascode tube, effectively reducing the input offset voltage of the operational amplifier system. When a large external source / sink current exists, the CLASS_AB output stage control circuit (102) is current-limited to limit the internal maximum power consumption, thereby reducing both heat generation and useless power consumption, thereby broadening the application of the CLASS_AB output stage operational amplifier in low-voltage, high-precision circuit systems.

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 application relates to a full common-mode range offset voltage trimming operational amplifier, relates to integrated circuit technology, and comprises an operational amplifier circuit and a trimming circuit, characterized in that the trimming circuit comprises a first current source (101) to a seventh current source (107), and a fifteenth NMOS tube (M15) to a thirtieth PMOS tube (M30), a current output end of a sixth current source (106) is connected with a current input end of the seventh current source (107), and a gate is connected with a positive level input line. The application can correct the full common-mode range offset voltage of a rail-to-rail input operational amplifier to a target value, and the input offset voltage almost does not change with the change of a common-mode voltage, so that the linearity of the full common-mode range of the operational amplifier is improved.

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.

The present application relates to a method, device, computer equipment, computer-readable storage medium and computer program product for constructing a reliability prediction model of a bipolar operational amplifier. The method includes: conducting a constant stress accelerated life test on a transistor to obtain data on the variation relationship of the normalized β value with time duration, performing parameter fitting on the variation relationship data to obtain the acceleration degradation coefficient, time power coefficient and undetermined coefficient of the transistor, and establishing a degradation trajectory model of the transistor; establishing a circuit simulation model of a differential input structure, and obtaining, through orthogonal experiments, data on the influence of the normalized β value on the input offset voltage of the bipolar operational amplifier; establishing a mapping relationship between the normalized β value and the input offset voltage of the bipolar operational amplifier according to the influence data; and establishing a reliability prediction model of the bipolar operational amplifier by using the degradation trajectory model and the mapping relationship. The use of this method can improve the accuracy and efficiency of the reliability prediction of the bipolar operational amplifier.

The invention provides a low-cost switching power supply for high-precision electric energy metering and a control method thereof. A voltage output pin of a switching power supply chip is grounded through a first capacitor; an external low-voltage power supply is connected and charges the first capacitor through the first resistor and the first diode, and the maximum soft start current of the boost power supply circuit is limited to be less than 100mA by setting the resistance value of the first resistor; an external low-voltage power supply is connected to a power supply input pin of the switching power supply chip through a sampling resistor, the sampling resistor is connected with an in-phase input end and an inverted input end of a voltage comparator, and whether overcurrent occurs or not is judged according to high or low level signals output by the voltage comparator; the over-current protection threshold value of the USB power supply circuit is limited by setting the resistance tolerance level and the input offset voltage of the voltage comparator. By designing the soft start and overcurrent protection circuit, the USB power supply with surge current prevention and precise overcurrent protection functions is provided, and the effects of greatly reducing the cost, simplifying the circuit design and improving the circuit reliability are achieved.

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).

An enhanced auto-zero circuitry and technique for reducing the effective input offset voltage of an amplifier. The circuitry includes a multi-phase auto-zeroing amplifier circuitry including several capacitor and switch components and a switch controller circuit. The switch controller circuit is configured to provide control signals for controlling the switches, where during a first sub-phase of an auto-zero phase, multiple switches are turned on to store an amplifier input offset coarser compensation charge on the input capacitor, and where during a second sub-phase of the auto-zero phase, at least one switch is turned off before turning on another switch to store an amplifier input offset finer compensation charge on the input capacitor via the first auto-zero capacitor.

The present invention belongs to the technical field of operational amplifiers, and particularly relates to a fully differential low-offset high-gain operational amplifier. The present invention includes an operational amplifier core and a feedforward common-mode feedback. The operational amplifier core amplifies the differential signal, and the feedforward common-mode feedback circuit stabilizes the common-mode voltage of the input and output. The present invention uses a floating-biased common-gate circuit and a high-gain NPN transistor series resistor as a current mirror, which significantly improves the gain, reduces the input offset voltage, and at the same time has a high output swing and good stability, and is suitable for use in an analog front-end programmable gain circuit.

The embodiment of the invention provides a band-gap reference voltage source and a power supply chip, the band-gap reference voltage source comprises a band-gap reference module, a sampling and holding module and a voltage buffer module, under a sampling phase, the sampling and holding module obtains a reference sampling voltage equal to a reference voltage, and the voltage buffer module obtains an offset sampling voltage; the sampling holding module is used for holding the reference sampling voltage and eliminating the third input offset voltage and the fourth input offset voltage based on the target sampling voltage so as to output a buffer voltage equal to the reference sampling voltage, the sampling holding module keeps the reference sampling voltage equal to the reference voltage under the holding phase, and the voltage buffer module obtains the target sampling voltage; and the first input offset voltage, the second input offset voltage, the third input offset voltage and the fourth input offset voltage are offset based on the offset sampling voltage to output the buffer voltage, so that high precision and low power consumption of the voltage source can be realized, and the suppression capability of load interference can also be improved.

A high-precision current acquisition circuit provided by the present invention, the high-precision current acquisition circuit includes: a control module, a first acquisition module, a second acquisition module, and an operational amplifier module; the first acquisition module and the second acquisition module form a mirror acquisition current structure; the second acquisition module includes a second power transistor; the first acquisition module includes N first power transistors, and the sizes of the N first power transistors are different, so that the ratio K value of the size of each first power transistor to the size of the second power transistor is different; wherein, N is a positive integer, and N≥2; the control module is used to select any one of the N first power transistors as the selected power transistor; and is used to control the working states of the second power transistor and the selected power transistor; the control module adjusts the K value by switching different first power transistors as the selected power transistor, so as to weaken the acquisition error caused by the input offset voltage of the operational amplifier and improve the acquisition accuracy.

The invention relates to the technical field of operational amplifier circuits, in particular to an in-phase operational amplifier circuit for eliminating input offset voltage. The in-phase operational amplifier circuit comprises: an input port for receiving an input voltage; the reference resistor is used for setting input voltage gain; the output resistor part is connected between the output port and the input port and comprises a plurality of output resistors which are connected in series; a current applying unit for applying a current to the output resistor unit, the current applying unit including a plurality of current sources and connected to a node between the output resistors; the digital control code generating part is used for adjusting the magnitude of the current; wherein the output voltage of the output port minimizes a residual offset voltage in the output voltage by compensating for the input offset voltage and a voltage drop caused by the current application unit while maintaining an amplification gain for the input voltage. By adopting the embodiment of the invention, the offset of the output offset voltage caused by the input offset voltage of the operational amplifier and appearing at the output end is facilitated.

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 invention discloses a circuit for measuring input offset voltage, comprising: a first resistor R1, a first end of which is connected to a first voltage input end of an operational amplifier, and a second end of which is connected to a first end of a second switch; a second end of the second switch, a second end of which is connected to a voltage output end of the operational amplifier and to a first end of a third switch; a second end of the third switch, a second end of which is connected to the first end of the first switch and to an input end of an analog-to-digital converter ADC; and a second end of the first switch, a second end of which is connected to an output end of a DC voltage source.

To provide a differential circuit in which the input offset voltage and the temperature drift coefficient of the input offset voltage are both improved without deteriorating noise or frequency characteristics and without affecting the input voltage range.SOLUTION: A first current circuit 12 supplies current to a differential input pair 11. A first trimming circuit 13 includes trimming resistors R1 and R2. A second trimming circuit 14 includes trimming resistors R3 and R4. A second current circuit 15 supplies current to the trimming resistors R3 and R4. A current ITAIL supplied from the first current circuit 12 to the differential input pair 11 and currents IFD1 and IFD2 supplied from the second current circuit 15 to the trimming resistors R3 and R4 have different temperature dependencies.SELECTED DRAWING: Figure 1

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 present invention provides a dynamic latch comparator. The dynamic latch includes a latch circuit and a flag signal generation circuit. The latch circuit is specifically a double-input and double-output latch circuit. The dynamic latch further includes a first level decision circuit and a second level decision circuit for correspondingly buffering the two outputs of the latch circuit, and further includes a third level decision circuit for buffering the output of the flag signal generation circuit. The present invention solves the problem of excessive comparator input offset voltage during the quantization process, improves the gain of the comparator, reduces the input offset voltage, can drive a larger current, and reduces the influence of dynamic offset.

The invention provides a high-precision Delta Sigma analog-to-digital converter, which is applied to the technical field of analog-to-digital conversion and comprises an input end quantizer, a dual-channel sampling module, a modulator and a calibration digital filter, an analog input signal enters the dual-channel sampling module after passing through the input end quantizer and then enters the modulator for noise shaping so as to obtain a digital output signal, and the digital output signal is output to the calibration digital filter. On one hand, the digital output signal is accessed to the input end of the dual-channel sampling module for signal feedback, and on the other hand, the digital output signal is multiplied by corresponding calibration coefficients according to different stages of the control signal and then is filtered by the calibration digital filter, and after input offset voltage is removed from the filtered signal, the calibrated digital output signal can be obtained. According to the high-precision Delta Sigma analog-to-digital converter, the power supply voltage of a modulation loop is reduced under the condition that the amplitude of an input signal is not reduced, the power consumption of a modulator is reduced, and the problem of mismatch between different channels in a double-sampling technology is solved through calibration.

The invention relates to the technical field of electronics, in particular to a current detection circuit, a chip and electronic equipment. The current detection circuit comprises a power unit, a detection unit, a clamping operational amplifier, a compensation resistor unit and a compensation current module. The power unit is connected with the detection unit; the first input end of the clamping operational amplifier is connected with the power unit, the second input end of the clamping operational amplifier is connected with the first end of the compensation resistor unit, and the second end of the compensation resistor unit is connected with the detection unit; the compensation current module is connected with the first end of the compensation resistor unit. According to the embodiment of the invention, the compensation current module and the compensation resistor unit can provide the compensation voltage for the current detection circuit, so that the input offset voltage between the input ends of the clamping operational amplifier is offset, and the problem of power consumption dispersion caused by the input offset voltage is avoided.

The application provides a low-cost switching power supply for high-precision electric energy metering and a control method thereof, comprising that the voltage output pin of a switching power supply chip is grounded through a first capacitor; an external low-voltage power supply is connected to and charges the first capacitor through a first resistor and a first diode pair, and the maximum soft start current of a boost power supply circuit is limited to less than 100mA by setting the resistance value of the first resistor; the external low-voltage power supply is connected to the power input pin of the switching power supply chip through a sampling resistor, the sampling resistor is connected to the non-inverting input terminal and the inverting input terminal of a voltage comparator, and whether overcurrent occurs is judged according to the high or low level signal output by the voltage comparator; and the overcurrent protection threshold of a USB power supply circuit is limited by setting the resistance value tolerance level and the input offset voltage of the voltage comparator. The application provides the USB power supply with the functions of surge current prevention and accurate overcurrent protection by designing the soft start and overcurrent protection circuits, so that the cost is greatly reduced, the circuit design is simplified, and the circuit reliability is improved.