131 results about "Common mode feedback" patented technology

The invention provides a common-mode feedback circuit and a differential amplifier thereof, the common-mode feedback circuit comprises a sampling circuit and an amplifier circuit, the sampling circuit comprises a first input end, a second input end and a first output end, the first input end receives a first differential signal Voutp, and the second input end receives a second differential signal Voutn; the level shift module comprises a third input end, a fourth input end and a second output end, receives a common-mode signal VCMS and a reference common-mode signal VOCM output by the sampling circuit, and adjusts the common mode of the common-mode signal VCMS and the reference common-mode signal VOCM to enable the second output end to output a common-mode feedback signal VCMFB processed by the level shift module; the amplifier circuit receives a common mode feedback signal VCMFB. After the technical scheme is adopted, the same speed as that of a differential loop can be realized, the current of a main operational amplifier can be multiplexed, the power consumption of a common-mode loop is far lower than that of a main loop, and meanwhile, the common-mode level can be randomly adjusted.

The invention provides a fully differential operational amplifier circuit and an operational amplifier. The fully differential operational amplifier circuit comprises an input stage circuit, a gain stage circuit and a common-mode feedback circuit, the input stage circuit is used for processing a differential input voltage signal, converting the differential input voltage signal into a differential current signal and transmitting the differential current signal to the gain stage circuit; the gain stage circuit is used for performing gain processing on the differential current signal and outputting a target differential voltage signal; the common-mode feedback circuit is used for detecting the common-mode voltage of the target differential voltage signal, generating a common-mode feedback signal and transmitting the common-mode feedback signal to the gain-stage circuit to stabilize the common-mode voltage; wherein the gain stage circuit comprises a gain enhancement circuit, and the gain enhancement circuit is used for increasing the output impedance of the gain stage circuit. According to the chopping operational amplifier, the input stage circuit, the gain stage circuit, the common mode feedback circuit and the gain enhancement circuit are combined, so that the precision and the sensitivity of the chopping operational amplifier are improved.

This disclosure describes an apparatus that enables rapid transitions during microwave-assisted magnetic recording (MAMR) of storage media. In various aspects, the apparatus incorporates a driver circuit configured to provide a controlled bias current through separate source and sink output terminals, which respond to feedback signals. An MAMR sensor connects between the source and sink output terminals and generates microwave fields when receiving the controlled bias current from the driver circuit. A common-mode feedback (CMFB) loop connects to the source and sink output terminals, detects common-mode voltage (CMV), and delivers feedback signals to the driver circuit to maintain CMV regulation of the MAMR sensor. A differential voltage regulation loop connects to the source and sink output terminals, providing feedback signals that maintain the MAMR sensor voltage differential at a reference value. The apparatus controls the magnetic recording process of the MAMR sensor with rapid transition times.

The invention discloses an amplitude-adjustable attenuation circuit network for differential signal transmission. The amplitude-adjustable attenuation circuit network is composed of an attenuator I and an attenuator II. Wherein a common-mode feedback circuit is arranged between the attenuator I and the attenuator II. The attenuator I is introduced into an anti-ESD impact module which is composed of an input end back-to-back diode and used for resisting ESD impact. Differential signals at the input end of the attenuator I are subjected to voltage division through fixed resistors RS1 and RS1 < n > and binary weight adjustable resistors RS2 and RS2 < n >, the attenuator II is connected to a transmission channel in parallel, and the differential signals are subjected to further differential mode attenuation through binary weight adjustable capacitors CSp and CSn. The attenuation circuit network dynamically switches attenuation paths through an MOS tube switch matrix, respectively supports attenuation amounts from-1dB to-6dB and from-0.3 dB to-7dB, realizes high stepping precision, finally realizes synchronous attenuation for common-mode and differential-mode voltages, retains differential-mode attenuation of common-mode levels, and optimizes low-frequency amplitude attenuation and high-frequency signal integrity at the same time.

The invention relates to a low-power-consumption high-performance D-type power amplifier modulation method and circuit and a D-type audio power amplifier, and the method comprises the steps: separating a pair of BD mode modulated signals outputted by a PWM modulation module in the D-type audio power amplifier circuit into a common mode component and a differential mode component, and outputting the common mode component and the differential mode component; feeding back the common-mode component and the differential-mode component to a differential input end through a common-mode feedback link and a differential-mode feedback link respectively; wherein the common-mode component and the common-mode feedback link are completely arranged in the chip; the differential mode component and the differential mode feedback link are realized by a power MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) integrated inside the chip or an external power MOSFET; and outputting the differential mode component to a to-be-driven object through the power output stage. According to the method, after two feedback links are separated, in a zero-input mute state, no common-mode signal is sent to an output stage for amplification, and power consumption is not caused at the output stage, so that the overall efficiency is greatly improved; and meanwhile, static bottom noise is almost eliminated.

A power amplifier using multi-path common-mode feedback loops for radio frequency linearization is disclosed. In one aspect, a complementary metal oxide semiconductor (CMOS) power amplifier containing cascoded n-type field effect transistors (NFETs) and cascoded p-type FETs (PFETs) may have a common-mode feedback network and provides bias voltages that are dynamically varying with the signal power to keep the output common-mode fixed around a half-supply level, while the small-signal and large-signal transconductances of the FET's are kept balanced. A further feedback network may be associated with the supply voltage to assist in providing a symmetrical supply signal. The symmetrical supply signal allows for supply variations without introducing distortion for the power amplifier stage.

The application provides a common-source common-gate amplifier, comprising a signal input module, which is used for generating an input signal according to a power supply voltage; a cross-coupling module, which is electrically connected with the signal input module and is used for forming internal positive feedback according to an output signal; a first biasing module, which is electrically connected with the cross-coupling module; a first branch module, which is electrically connected with the first biasing module; a second biasing module, which is electrically connected with the cross-coupling module; a second branch module, which is electrically connected with the second biasing module; wherein the first biasing module and the second biasing module are used for providing biasing after an input common-mode feedback voltage, the first branch module and the second branch module are used for providing large-swing output biasing, and the first branch module and the second branch module are respectively electrically connected with the signal input module, and the signal input module is further used for outputting branch signals to the first branch module and the second branch module. The application improves the voltage swing, the gain and the bandwidth of the circuit under the single-stage amplifier structure.

This application provides an operational amplifier that increases the stability and settling speed of a common-mode feedback circuit. The operational amplifier includes N stages of amplifiers connected in series and M common-mode feedback circuits, where N and M are integers, N≥3, and N≥M>1. An ith common-mode feedback circuit in the M common-mode feedback circuits is configured to: detect a common-mode output voltage of a (j+b)th stage of amplifier, and regulate an electrical parameter of at least one of the jth stage of amplifier to the (j+b)th stage of amplifier, to stabilize the common-mode output voltage of the (j+b)th stage of amplifier. An Mth common-mode feedback circuit is configured to detect and stabilize a common-mode output voltage of an Nth stage of amplifier. Herein i, j, and b are integers, M≥i≥1, N≥j≥1, i≥j, j+b≤N, and b≥0.

This application provides a buffer and chip. The buffer includes a first conversion circuit, a second conversion circuit, and a common-mode feedback circuit. The first conversion circuit outputs a first output signal based on a first input signal, a first bias voltage, and a first substrate bias voltage of a first main input transistor. The first substrate bias voltage includes an initial and an adjusted first substrate bias voltage. The second conversion circuit outputs a second output signal based on a second input signal, the first bias voltage, and a second substrate bias voltage of a second main input transistor. The second substrate bias voltage includes an initial and an adjusted second substrate bias voltage. The common-mode feedback circuit generates a common-mode signal based on the first and second output signals. Based on the common-mode signal and a target voltage value, it generates and adjusts the first and second substrate bias voltages based on the feedback signal. Because the common-mode feedback circuit adjusts the substrate voltage of the main input transistor, it maintains the stability of the common-mode signal, thereby improving the linearity and stability of the buffer.

The invention provides a gain programmable analog front-end circuit with common-mode adjustment. The circuit comprises a programmable gain amplification module, an output buffer module and a common-mode feedback module, the output of the programmable gain amplification module is connected with the input of the output buffer module, and the programmable gain amplification module is used for adjusting the input voltage gain; the outputs of the two ends of the output buffer module are used for driving a post-stage load and are connected with the common-mode feedback module; and the common-mode feedback module is connected with the programmable gain amplification module and the output of the output buffer module and is used for adjusting the common-mode voltage output by the output buffer module in real time according to requirements and adjusting the common-mode voltage to a required range. According to the analog front-end circuit, gain adjustment can be realized, a post-stage load can be driven, the common-mode voltage can be adjusted in real time according to requirements, and the output common-mode voltage can be adjusted to a required low-voltage range under the conditions that extra power consumption is not increased and original VGA current and input common mode are not changed.

This invention relates to the field of high-resolution time measurement systems and integrated circuit technology, providing a time measurement circuit with a two-dimensional address-modulated TOT pulse, comprising: a common-gate transimpedance amplifier, a high-speed high-gain comparator, a current-mode logic output stage, a common-mode feedback threshold setting circuit, and a two-dimensional address-modulated TOT pulse circuit; the address modulation pulse circuit includes an address modulation pulse width circuit and an address modulation pulse amplitude circuit, wherein the address modulation pulse width circuit includes: multiple sets of first modulation units, multiple sets of second modulation units, multiple inverters, and multiple bits of first digital code; the address modulation pulse amplitude circuit includes: multiple sets of third modulation units and multiple bits of second digital code. This invention allows a single TOT signal to simultaneously carry time information, energy information, and address information, reducing wiring, improving reliability, and increasing integration density.

The invention provides an operational amplifier and a layout structure thereof. The layout structure comprises a first layout area, a second layout area and a third layout area which are sequentially arranged along a first direction, a first compensation capacitor array area and a second compensation capacitor array area are respectively arranged in the first layout area and the third layout area; a differential pair transistor region, a first common-mode feedback region, a first load region, a second load region, a second common-mode feedback region and an amplifying circuit output region which are sequentially arranged along a second direction are arranged in the second layout region, and the first chopping region and the second chopping region are arranged on two sides of the first load region or the second load region along the first direction; the first chopping region is close to the first layout region, and the second chopping region is close to the third layout region. According to the method, the layout design work of the differential pair in the simulation layout design can be effectively and quickly realized, the process dependence is reduced, the structure of the differential pair can be strictly controlled, and the high symmetry is ensured.

A high-speed CMOS LVDS transmitter disclosed by the present invention comprises a digital unit and an analog unit, the digital unit is used for generating a differential signal and a pre-emphasis signal, the analog unit is used for realizing analog differential output, and the digital unit comprises a level shift circuit module, a single-end-to-double-end circuit module and a pre-emphasis control signal module. The simulation unit comprises a current bias circuit module, an LVDS transmitter core circuit module and a common-mode feedback circuit module, the LVDS transmitter is simple in structure and ingenious in design, the speed and quality of signal transmission can be guaranteed, meanwhile, power consumption and production cost are reduced, the LVDS transmitter has great significance in development of the domestic high-speed transmission technology, the application prospect is wide, and the application range is wide. Popularization and application are facilitated.

This invention relates to the field of communication technology and discloses a circuit and electronic device for driving a passive mixer for up-conversion. The common-mode voltage of the differential signal is adjusted through a common-mode feedback adjustment network, and the adjusted voltage flows to a common-mode voltage control circuit. A drive control circuit outputs a drive control signal based on the differential signal to power the passive mixer. The common-mode voltage control circuit outputs a voltage control signal based on the adjusted voltage and a reference voltage, ensuring the common-mode voltage is regulated by the common-mode feedback adjustment network. Therefore, implementing this invention enables precise driving of the passive mixer through the processing of the differential signal by the drive control circuit. This is beneficial for improving the mixing gain of the passive mixer through drive control based on the drive control circuit, and it can improve the stability of the differential signal by setting up the common-mode feedback adjustment network and the common-mode voltage control circuit, thereby reducing the impact on the noise, bandwidth, and linearity of the mixing system.

This invention provides a transmitter circuit for a CAN bus, relating to the field of CAN bus communication. The circuit includes: a common-mode feedback circuit for generating first and second gate voltages; a slew rate control circuit comprising a CANH terminal circuit for receiving the first gate voltage and a CANL terminal circuit for receiving the second gate voltage, each terminal circuit including multiple sequentially connected delay units and power transistors, the delay units controlling the gate voltage of the power transistors stage by stage to alternately switch the power transistors; and a port positive and negative high-voltage protection circuit, respectively connected between the output terminals of the CANH and CANL terminal circuits and the bus port, for protecting against positive and negative high voltages on the bus and suppressing parasitic effects. The beneficial effects are: by controlling the switching of the power transistors stage by stage through the delay units, the current surge rate is reduced, and electromagnetic radiation is reduced; by stabilizing the gate voltage and balancing the output current through common-mode feedback, signal symmetry is improved and common-mode interference is suppressed.

The invention discloses a fully differential amplifier circuit with rail-to-rail output. The fully differential amplifier circuit comprises a main amplifier circuit, a first-stage common-mode feedback circuit, a second-stage common-mode feedback circuit and a voltage regulation circuit. The main amplifier circuit comprises a first-stage main amplifier and a second-stage main amplifier which are cascaded; the first-stage common-mode feedback circuit comprises an amplifier Af1, a first input end of the amplifier Af1 is connected to the first-stage differential output end, a second input end of the amplifier Af1 is connected with a first reference voltage end, and the amplifier Af1 compares common-mode voltage output by the first-stage main amplifier with first reference voltage VREF1 and feeds back error quantity to the first-stage main amplifier; the second-stage common-mode feedback circuit comprises an amplifier Af2; the input end of the voltage adjusting circuit is connected with the output end of the amplifier Af2, and the output end of the voltage adjusting circuit provides adjustable first reference voltage for the first reference voltage end. According to the circuit, it can be guaranteed that the output common-mode level is fast and stable, and rail-to-rail output is achieved.

The invention discloses a bipolar voltage-time converter based on phase inverter threshold detection. The bipolar voltage-time converter is characterized in that a differential sampling circuit is connected with a sign bit comparator and a bipolar voltage-time conversion circuit; the sign bit comparator is used for receiving the differential sampling voltage output by the differential sampling circuit and judging the polarity of an input differential analog signal, and is connected with the bipolar voltage-time conversion circuit to output a sign bit signal and a polarity control signal; the bipolar voltage-time conversion circuit is used for charging or discharging the differential sampling voltage under the control of the polarity control signal to generate two paths of voltage ramp signals with opposite polarities, and is connected with the common-mode feedback circuit and the inverter threshold detection circuit; the common-mode feedback circuit is used for detecting a common-mode level of the differential sampling voltage or two paths of voltage ramp signals; the threshold voltage of the inverter threshold detection circuit is configured to be a predetermined common-mode level, and is used for detecting a crossover event of the two voltage ramp signals at the predetermined common-mode level and outputting a threshold detection signal.

The present disclosure describes aspects of a differential current-mode (iMode) driver for microwave-assisted magnetic recording (MAMR) application in hard-disk drives. In some aspects, an iMode driver circuitry employs a driver circuit coupled to power supply connections. The driver circuit is configured to provide a controlled differential bias current and includes separate source and sink output terminals. A MAMR sensor couples between the source and sink output terminals, through which the MAMR sensor receives the controlled differential bias current provided by the driver circuit. The MAMR sensor, which has a field-entry terminal and a field-exit terminal, generates microwave fields for the recording process. A common-mode feedback (CMFB) loop couples to the field-entry and field-exit terminals of the MAMR sensor, forming a feedback pathway with the driver circuit. This CMFB loop detects common-mode voltage (CMV) and adjusts the controlled differential bias current to maintain CMV regulation of the MAMR sensor.

In some aspects, the disclosure is directed to methods and systems for an amplifier having common mode feedback inputs. The inputs are coupled to various points within an amplifier wherein a first set of directly coupled common mode feedback inputs join the amplifier one or more nodes, and a second set of capacitively coupled common mode feedback inputs are joined to the amplifier at one or more different nodes.

The present invention discloses a common-mode feedback circuit, control method, and operational amplifier, relating to the field of circuit design technology. The common-mode feedback circuit includes: a common-mode sensing and error amplification subcircuit and a current summing subcircuit for providing a common-mode feedback voltage; the current summing subcircuit is coupled to the common-mode sensing and error amplification subcircuit; the common-mode sensing and error amplification subcircuit includes two sets of differential amplifier input transistors with opposite polarity, each set of differential amplifier input transistors including two pairs of transistors with the same polarity, one transistor in each pair of transistors being controlled by a differential output signal, and the other transistor being controlled by a common-mode signal. The control method described above applies to the common-mode feedback circuit. The operational amplifier described above includes the common-mode feedback circuit.

The invention relates to the technical field of analog-to-digital conversion, and discloses a ring amplifier and an analog-to-digital converter, the ring amplifier comprises a cascade phase inverter and two short-circuit phase inverters, and each stage of phase inverter of the cascade phase inverter comprises two single-stage phase inverters; each of the short-circuit phase inverter and the single-stage phase inverter comprises two complementary MOS (Metal Oxide Semiconductor) tubes; the grid electrodes of the two MOS tubes of the short-circuit inverter are in short circuit with the drain electrodes of the two MOS tubes of the short-circuit inverter; the control voltage and the input voltage of the ring amplifier are accessed to the first-stage inverter in the cascaded inverters, and the control voltage is the output voltage of a common-mode feedback circuit of the ring amplifier; and the drain electrode of the output-stage phase inverter in the cascaded phase inverters is used as the differential output end of the ring amplifier. The short-circuit inverter is used for replacing a resistor in the related technology, so that dead-zone voltage is effectively avoided, and the ring amplifier can output stable differential signals.

A common-mode feedback circuit for a fully differential amplifier comprises first (MB), second (MTP), and third (MTN) transistors, each having a respective drain, source, gate, and back-gate terminals. The drain terminal of the first transistor (MB) and the gate terminals of the first, second, and third transistors (MB, MTP, MTN) are connected together at a bias current terminal. The drain terminals of the second and third transistors are connected together at a tail current terminal. The source terminals of the first, second, and third transistors are connected together. The back-gate terminal of the first transistor (MB) is arranged to receive a common-mode reference voltage input (VCM), the back-gate terminal of the second transistor (MTP) is arranged to receive a positive output voltage (VP) from the fully differential amplifier, and the back-gate terminal of the third transistor (MTN) is arranged to receive a negative output voltage (VN) from the fully differential amplifier.

An operational amplifier includes a first stage of the current-reuse type; and a second stage of the rail-to-rail type, cascaded with respect to the first stage. The first stage comprises a first feedback assembly configured to define a first common mode feedback loop. The second stage comprises a second feedback assembly configured to define a second common mode feedback loop. The first and second common mode feedback loops, of the first and second stages, respectively, are independent of each other.

A signal amplifying circuit includes an amplifier and a common mode feedback circuit. The amplifier generates first and second outputs. The common mode feedback circuit receives the first and second outputs, and controls an output common mode voltage of the first and second outputs to a first reference voltage. The common mode feedback circuit includes an output common mode voltage detection circuit, a pull-up circuit and a pull-down circuit. The output common mode voltage detection circuit generates first and second control signals according to the output common mode voltage. The pull-up circuit with a first conduction degree controlled by the first control signal controls the output common mode voltage to be positively correlated with the first conduction degree. The pull-down circuit with a second conduction degree controlled by the second control signal controls the output common mode voltage to be negatively correlated with the second conduction degree.

The embodiment of the utility model provides a fully-differential amplification circuit, a chip and electronic equipment, the fully-differential amplification circuit comprises a fully-differential amplification module and a common-mode feedback module, and the common-mode feedback module comprises a voltage acquisition unit, a piezoelectric conversion unit, a mirror image unit and a feedback output unit. A feedback loop of common-mode voltage is realized through the voltage acquisition unit, the piezoelectric conversion unit, the mirror image unit and the feedback output unit, and the feedback loop is prevented from using a voltage comparator, so that the use number of transistors in the feedback loop is reduced, and the cost and the occupied area are further reduced.

The invention discloses an analog front-end chip for ultrasonic imaging digital beam forming. The circuit comprises a low noise amplifier (LNA) and an analog-to-digital converter (ADC). The noise amplifier LNA comprises a programmable gain amplifier PGA and an output stage amplifier; the main structure of the PGA is a pseudo-differential capacitance feedback amplifier, and the function of time gain compensation TGC is achieved by changing the proportion of input capacitance and output capacitance. The output-stage amplifier is a two-stage amplifier, and the first-stage operational transconductance amplifier OTA is of an Inver-Based structure; the OTA at the second stage adopts a class-AB structure; the OTA of the first stage and the OTA of the second stage use independent common-mode feedback; a closed-loop structure of the output-stage amplifier is realized by adopting a split capacitor structure; according to the invention, digital-to-analog conversion of a single channel is realized by adopting the SAR ADC, and the analog front end for ultrasound with a high dynamic range and a high signal-to-noise ratio is realized with relatively small power consumption and area.

The application provides a common-mode feedback circuit with a level conversion function, comprising an amplifier output stage, a resistive common-mode feedback circuit and an amplifier common-mode feedback circuit, the amplifier output stage comprising a first current source I1, a second current source I2, a tail current source I3, input pair tubes M1 and M2 and a common-mode adjusting tube M3, the resistive common-mode feedback circuit comprising a first resistor R1 and a second resistor R2, and the amplifier common-mode feedback circuit comprising a third resistor R3, a fourth resistor R4 and a first operational amplifier AMP1, V OP and V ON The input ports of the resistive common-mode feedback circuit and the amplifier common-mode feedback circuit are commonly connected, for detecting the common-mode voltage and adjusting the common-mode adjusting tube at the same time. The scheme introduces the fast response advantage of the amplifier feedback on the basis of the resistive feedback, realizes the accurate control and dynamic adjustment of the common-mode level, and makes the output common-mode voltage be flexibly set by integrating the level conversion function in the feedback loop, so that the transient response speed of the system is significantly improved.

A system may include a pulse-width modulation mode path configured to drive a load at an output of the system in a first mode of operation, a linear mode path configured to drive the load in a second mode of operation, a common mode control feedback loop configured to set a value of a common mode output signal at the output in the second mode of operation, and an auxiliary circuit coupled to the common mode feedback control loop and configured to maintain a state of the common mode feedback control loop during the first mode of operation as the state was or will be during the second mode of operation.

The present application relates to a kind of earphone type brain electricity collection front-end anti-interference system, including electrode acquisition unit, static electricity protection unit, front-end pollution suppression unit, input anti-interference filter unit, analog front-end acquisition unit, common mode feedback / bias drive unit, power supply and reference stable unit, common ground layout unit, interference monitoring unit and anti-interference control unit.The earphone type brain electricity collection front-end anti-interference system, method, device, processor and its computer readable storage medium of the present application are used, the interference of two different sources of transient impact and chronic leakage can be more accurately governed, the common mode rejection ratio can be improved, baseline drift caused by wearing state change, high impedance contact and human coupling can be reduced, overall noise can be reduced, and data stability and availability can be improved in brain electricity collection and wireless communication concurrent scene.

The present invention provides an anti-common-mode voltage lockout circuit for a fully differential operational amplifier, comprising: a two-stage operational amplifier main circuit, a common-mode feedback circuit, and an anti-lockout circuit; the anti-lockout circuit comprises a first MOS transistor, a second MOS transistor, a third MOS transistor, and a resistor, the gate of the first MOS transistor being connected to the input of the common-mode feedback circuit, the drain of the first MOS transistor, the gate of the second MOS transistor, and the gate of the third MOS transistor being connected to the resistor, and the drain of the second MOS transistor and the drain of the third MOS transistor being connected to the output of the first stage circuit of the operational amplifier of the two-stage operational amplifier main circuit. The present invention has a simple circuit structure, consumes few resources, quickly releases lockout, has little impact on the performance of the operational amplifier itself, and is suitable for a wide range of scenarios.