23 results about "Chopper amplifier" patented technology

The present invention belongs to the field of measurement and discloses a Hall sensor circuit comprising a Hall sensor, a rotary switch circuit connected to the Hall sensor, and a ripple-eliminating chopper amplifier connected to the rotary switch circuit; the ripple-eliminating chopper amplifier comprises a first amplifier and a second amplifier connected in series, and also comprises a first negative feedback circuit; the first negative feedback circuit comprises a ripple-eliminating loop and a transconductance amplifier connected to the ripple-eliminating loop, the output of the transconductance amplifier being connected to the input of the second amplifier; the ripple-eliminating loop comprises a chopper and an integrator, wherein the chopper input is coupled to the output of the second amplifier, the chopper output is coupled to the input of the integrator, and the output of the integrator is coupled to the transconductance amplifier. The above technical solution achieves high bandwidth, fast response speed, high measurement accuracy, low noise, and low offset voltage.

The present disclosure relates to chopper amplifier circuits featuring inherent chopper ripple suppression. A chopper amplifier circuit includes a modulator circuit tuned to a chopper frequency, and configured, in accordance with the chopper frequency, to convert a voltage into an AC voltage; an amplifier circuit having inverting and non-inverting inputs for the AC voltage, and having inverting and non-inverting outputs for an amplified AC voltage; a demodulator circuit tuned to the chopper frequency, and configured to convert the amplified AC voltage into an amplified DC voltage, the inverting output being coupled, via a first capacitance in a first signal path, to a first input of the demodulator circuit, the non-inverting output being coupled, via a second capacitance in a second signal path, to a second input of the demodulator circuit; and a discharge resistor circuit coupled on an output side of both capacitances between the first and second signal paths.

The invention discloses a novel wide-range high-precision temperature sensor circuit based on a BJT architecture. The novel wide-range high-precision temperature sensor circuit comprises a temperature sensing core circuit, a bias current generating circuit, a chopping amplifier, a starting circuit and an SAR ADC reading circuit. A cascode current mirror is adopted in the bias current generating circuit, and the DEM technology is adopted in the temperature sensing front-end circuit to reduce mismatch. In order to reduce the influence caused by the offset voltage and 1 / f noise of the operational amplifier, compared with the traditional chopping operational amplifier, the novel chopping technology is used for the operational amplifier to further reduce the offset voltage and noise. Meanwhile, limited current gain compensation, second-order curvature compensation and circuit gain detection are innovatively introduced to reduce errors. Compared with the prior art, the structure design of the temperature sensor with higher precision can be better realized while the noise is low, the range is large, and the stability is high. In addition, the temperature sensor based on the BJT architecture can be applied to the fields of aerospace, smart agriculture, wearable electronics, smart home and the like, and the application range is wide.

This invention relates to a chopper amplifier, comprising a clock generator module, an input chopper module, an amplifier module, and an output chopper module. The clock generator module includes a zero-crossover aligned clock circuit, which outputs an intermediate clock based on the differential input signal and detects the zero-crossover point, aligning the edge of the intermediate clock to the zero-crossover point to generate an aligned chopper clock. The output chopper module is connected to a self-filling circuit, which, in conjunction with the chopper clock, samples the differential output voltage during the chopper steady-state phase and, during the chopper transition phase, forms a short circuit between the differential output nodes, causing the current polarity of the amplifier module to internally reverse, while simultaneously performing self-filling. By utilizing zero-crossover aligned chopper technology and / or self-filling technology, intermodulation distortion caused by chopping is suppressed or eliminated mechanistically without increasing power consumption or noise, significantly improving the linearity and usable input frequency range of the chopper amplifier.

This invention discloses a noise suppression circuit for a quartz vibrating beam accelerometer. It employs a chopper-AGC closed-loop oscillation circuit to achieve stable driving of the quartz vibrating beam. The circuit includes a chopper amplifier, an AGC automatic control gain module, and a follower amplifier. The electrical signal generated during beam vibration is amplified by the chopper amplifier and low-frequency noise is filtered out, resulting in a noise-reduced signal. This noise-reduced signal is then stabilized by the AGC automatic control gain module and amplified and phase-compensated by the follower amplifier before being fed back to the quartz vibrating beam accelerometer head, forming a stable closed-loop drive. This invention uses chopper modulation technology to modulate the noise signal and input signal to different frequency bands, and uses filtering to separate the noise signal and input signal. This method effectively improves the zero-bias stability and noise performance of the QVBA system.

Provided is an amplifier that stably obtains an effective chopper amplifier gain with respect to a closed-loop gain setting, and that has good correction convenience. The amplifier includes: an input terminal; a chopper circuit capable of switching between a direct connection state and a cross connection state; a first resistor and a third resistor; a variable resistor; a first operational amplifier having an input end connected to the output end, a control end receiving a supplied control signal, and an input end connected to one end of the first resistor and one end of the variable resistor; a second operational amplifier having an input end connected to the output end, a control end receiving a supplied control signal, and an input end connected to one end of the third resistor and the other end of the variable resistor; and an output terminal configured so that the first operational amplifier and the second operational amplifier can switch their gain bandwidths on the basis of the control signal.

Embodiments of the present disclosure relate to a chopper amplifier circuit and a method for operating a chopper amplifier circuit. The present disclosure relates to a chopper amplifier circuit with inherent chopper ripple rejection.

The present application relates to a kind of variable gain chopper amplifier for biological signal sensing system, belong to the field of analog integrated circuit design, including two chopping switches S1 and S2, bias circuit, gain control module, cascode module and filter.First, power supply and bias circuit provide stable power supply voltage and static working point for the whole circuit, then modulate useful signal to chopping frequency through chopping switch S1, signal is converted into a certain amount of current after voltage through gain control module, and then current is converted into amplified ac voltage signal through cascode module, signal is modulated back to baseband through chopping switch S2, finally, high-frequency part is filtered out through low-pass filter, and the amplified low-frequency useful signal is obtained.The present application not only effectively reduces the low-frequency noise of operational amplifier by chopping principle, suppresses the imbalance of amplifier, and realizes the function of variable gain, is suitable for wide input dynamic range low-frequency biological signal processing.

This application discloses a circuit and its control method for enhancing the input impedance of a chopper amplifier. The circuit includes an OTA operational amplifier module, a chopper module, an input capacitor, a feedback capacitor, a peak detector, a valley detector, a subtractor, a comparator integrator, and a variable capacitor. The method includes: acquiring a differential input signal and performing chopping and amplification processing to obtain an output signal; performing peak detection processing to obtain positive and negative peak voltages; performing subtraction calculations to obtain the peak-to-peak value of the OTA signal; performing integration and ripple filtering processing to obtain a DC voltage signal with amplitude information; converting it into a DC current signal with amplitude information, and performing current compensation on the differential input signal through a positive feedback loop. The embodiments of this application can accurately compensate for on-chip parasitic capacitances, thereby avoiding current draw from the signal source and enhancing the input impedance of the chopper capacitor-coupled instrumentation amplifier. This application can be widely applied in the field of analog integrated circuit design technology.

A high-voltage chopper-stabilized amplifier can include two paths to compensate for non-ideal electrical parameters. A first path, leading to a primary input of the amplifier, may include a first mux interface circuit to limit voltages at the primary input of the amplifier. A second path, leading to an auxiliary input of the amplifier, may include a chopper amplifier circuit. Despite the first mux interface circuit, a slew condition on the first path may excite a current in the second path that can negatively affect the signal source. Accordingly, the disclosed amplifier further includes a second mux interface circuit that can decouple the second path while a slew condition. The second mux interface circuit is driven by a window floating comparator, which is supplied according to the voltages on primary input. A settling enhancer circuit keeps, during slew condition, certain nodes on the second path at a reference voltage.

Amplifier with programmable gain (“PGA”) (100), comprising: a differential amplifier (A1) with one input pair (102, 104) and one output pair (106, 108), a pair of input capacitors (C IN , C IP ) with output terminals, each connected to inputs (102, 104) of the differential amplifier (A1), a pair of feedback capacitors (C FN , C FP ), which are each connected between the outputs of the differential amplifier (A1) and corresponding inputs of the differential amplifier (A1), a first chopper circuit (110) which is configured to connect the input capacitors (C IN , C IP ) to connect to the corresponding input terminals of the PGA (100), a second chopper circuit (120) configured to connect the output terminals (106, 108) of the differential amplifier (A1) to corresponding output terminals (VON, VOP) of the PGA (100), a first voltage source (V ICM ), which is configured to be connected to input terminals (102, 104) of the differential amplifier (A1) via corresponding sample switches, the corresponding sample switches being configured to close in response to a first control signal (CO) and the first voltage source (V ICM ) has a voltage that is set to a common-mode voltage of the differential amplifier (A1), and wherein the amplifier (A1) provides a second voltage source (V CMA ) which is configured with input terminals of the input capacitors (C IN , C IP) to be connected via appropriate scanning switches, the appropriate scanning switches being configured to close in response to a second control signal (COB) and the second voltage source (V CMA ) has a voltage that is set to a common-mode signal of signals to be input into the PGA (100).

The invention discloses a switch biasing circuit of a chopping amplifier, and belongs to the technical field of integrated circuits, VH and VL are respectively generated through an NMOS (N-channel metal oxide semiconductor) chopping switch gate voltage biasing circuit and a substrate biasing circuit, and the VH and the VL are respectively connected with the power supply end and the grounding end of a first phase inverter and the grounding end of a second phase inverter; the input end of the first phase inverter inputs a clock signal CLK, the output end of the first phase inverter is connected with the grid electrode of the NMOS chopping switch through the second phase inverter, the VL is connected with the substrate of the NMOS chopping switch, the source electrode of the NMOS chopping switch is connected with the in-phase end input voltage VINP of the chopping amplifier, and the drain electrode of the NMOS chopping switch is connected with an internal circuit of the chopping amplifier. According to the invention, the grid voltage of the NMOS chopper switch is biased through bootstrap of the input voltage, the substrate of the NMOS chopper switch is biased through subtraction of the bootstrap voltage, and the precision of the grid voltage and the substrate voltage of the NMOS chopper switch is ensured through a precision current bias technology.

A chopper circuit for a multipath chopper amplifier is described. The chopper circuit comprises a first chopper device in a first circuit path, wherein the first chopper device is configured to be controlled by a first clock signal, which has a first frequency; and a second chopper device in a second circuit path, parallel to the first circuit path, wherein the second chopper device is configured to be controlled by a second clock signal, which has a second frequency, wherein the first frequency is greater than the second frequency. Furthermore, a corresponding method of chopping an input signal is described.

The invention discloses a successive approximation type ripple suppression loop applied to a second-stage chopping amplifier, and the loop comprises a high-pass filtering module which is used for eliminating a DC offset component in an output signal of the second-stage chopping amplifier, and obtaining a high-frequency ripple signal; the demodulation module is used for modulating the high-frequency ripple signal into a low-frequency offset signal; the comparison module is used for quantizing the low-frequency offset signal into a digital level signal; the successive approximation logic module is used for carrying out logic judgment according to the digital level signal and generating a binary control code; and the compensation current source array module is used for performing current compensation on the first-stage chopping amplifier according to the binary control code. By means of the innovative circuit structure and working principle, the defects of an existing two-stage chopping amplifier ripple suppression technology are effectively overcome, the technical purposes of high ripple suppression ratio, low power consumption and high stability are achieved, and the two-stage chopping amplifier ripple suppression circuit is an effective means for suppressing two-stage chopping amplifier circuit ripples and has extremely high practical value and popularization prospects.

An integrated biopotential chopper amplifier with improved input impedance provided by the present invention reduces the size of the input pair transistors of the fully differential differential amplifier located between the chopper switches and the input capacitors, so as to reduce the equivalent input capacitance. Different from the traditional equivalent input capacitance which is mainly determined by the input capacitance, the equivalent input capacitance of the present invention is determined by the gate parasitic capacitance of the input pair transistors of the DDA structure. Therefore, the equivalent input capacitance can be reduced exponentially to the fF level, thereby greatly increasing the equivalent input impedance of the amplifier.

The present application discloses a PIR signal conditioning circuit, which includes a bias module, a chopper amplifier module, an analog-to-digital converter, a Fourier transform module, and a decision module. The bias module is configured to obtain an induction signal from a PIR sensor and a bias control word from the Fourier transform module, remove at least part of the DC component in the induction signal according to the bias control word, and output a bias waveform. The chopper amplifier module is configured to amplify the bias waveform to obtain a chopped waveform. The analog-to-digital converter is configured to sample the chopped waveform to obtain a sampled waveform in the digital domain. The Fourier transform module is configured to transform the sampled waveform into the frequency domain to obtain a detection waveform, output the zero-frequency component and non-zero frequency component in the detection waveform, and the zero-frequency component is used to determine the bias control word. The decision module is configured to determine whether there is a detection target according to the non-zero frequency component. The present application can improve the sensitivity of target detection based on PIR signals.

The invention discloses a low-voltage low-temperature-drift band-gap reference voltage source circuit. The circuit comprises a starting circuit, a band gap core circuit and a high-order temperature compensation circuit. In a low-voltage band gap core based on a Banba structure, offset voltage is actively eliminated through a chopping amplifier so as to suppress process deviation; meanwhile, a positive temperature coefficient voltage signal generated by the core loop is multiplexed and input into a high-order temperature compensation module, a nonlinear second-order compensation current activated only in an extreme temperature interval is generated, and the current is accurately injected into a specific node of an output resistance network. According to the compensation module, through a temperature coefficient current extractor and two adjusting channels with temperature selectivity, efficient and low-overhead offset of a bipolar transistor VBE high-order nonlinear temperature item is realized. According to the circuit, the static power consumption and the chip area are hardly increased while the temperature drift coefficient is remarkably reduced, and the circuit has excellent process deviation suppression capability.

The invention provides a frequency-locked loop based on a switched capacitor and a microcontroller, and the frequency-locked loop comprises a first current module which provides a first current; the switched capacitor module is connected in series with the first current module and cooperates with the first current to provide a first voltage. The voltage module provides a second voltage; the chopping amplifier outputs an amplified signal based on the first voltage and the second voltage; the voltage-controlled oscillator outputs a square wave signal according to the amplified signal; the non-overlapping clock generation module generates a first clock signal and a second clock signal under the action of the square wave signal; the switched capacitor filter is connected in series between the chopping amplifier and the voltage-controlled oscillator; under the condition that the second voltage is smaller than the first voltage, the amplification signal output by the chopping amplifier is reduced, the switched capacitor filter filters ripples in the square wave signal under the action of the first clock signal and the second clock signal, and the voltage-controlled oscillator outputs the square wave signal with reduced frequency, so that the equivalent impedance of the switched capacitor module is increased; the first voltage is equal to the second voltage.

A chopper amplifier circuit includes a modulator circuit tuned to a chopper frequency, the modulator circuit being configured, in accordance with the chopper frequency, to convert a voltage into an AC voltage; an amplifier circuit having an inverting input and a non-inverting input for the AC voltage, and having an inverting output and a non-inverting output for providing an amplified AC voltage; and a demodulator circuit tuned to the chopper frequency, the demodulator circuit being configured to convert the amplified AC voltage into an amplified DC voltage. The demodulator circuit is configured to, during different switching phases, couple each of the inverting and non-inverting outputs of the amplifier circuit, both directly and capacitively, to each inverting and non-inverting input of a summing circuit.

Described embodiments include an apparatus with a first amplifier having first inputs and first outputs. A second amplifier has second inputs and a second output. A first chopper circuit is coupled between third inputs and the first inputs. A second chopper circuit is coupled between the first outputs and the second inputs. A balanced filter is coupled to the second inputs.

The invention discloses a precise chopping instrument amplifier realized by utilizing automatic zero calibration. The precise chopping instrument amplifier comprises an automatic zero calibration module, a chopping modulation and demodulation module and a precise operational amplifier module. The whole circuit structure is a chopping stabilized amplifier. Before the amplifier works, the input of a high-frequency path and the input of a low-frequency path are short-circuited, and an output voltage value is fed back to the IDAC through automatic zero calibration logic, so that random mismatch caused by production and system mismatch existing in the circuit are eliminated, and residual input offset voltage after chopping is effectively eliminated; the precision of the amplifier is improved, and the area of the circuit is reduced. The method is suitable for high-precision measurement application.

The invention provides a voltage follower circuit, which is used for a chopping amplifier and comprises a first control voltage generation circuit used for receiving a differential input signal of the chopping amplifier and generating a first control voltage based on a direct current common mode voltage component in the differential input signal; the second control voltage generation circuit is used for receiving the differential input signal and generating a second control voltage based on a direct-current common-mode voltage component in the differential input signal; the first control voltage is configured to be power supply voltage of a two-phase non-overlapping clock generation circuit and a second control voltage generation circuit of the chopping amplifier; the second control voltage is configured to be the ground potential of the two-phase non-overlapping clock generation circuit and the chopper switch of the chopper amplifier; the first control voltage and the second control voltage act together, so that the gate-source voltage and the gate-substrate voltage of an MOS transistor in the chopper switch can change along with the common-mode voltage of the differential input signal to maintain a constant voltage difference value.

The invention relates to a dual self-zero-setting-chopping amplifier circuit. The dual self-zero-setting-chopping amplifier circuit comprises an input chopper, an input self-zero-setting module, a transconductance amplifier, an output chopper and an output self-zero-setting module, wherein the input chopper modulates an input differential signal to a chopping frequency; the input self-zeroing module suppresses the offset voltage of the transconductance amplifier to complete coarse self-zeroing operation; the transconductance amplifier amplifies an input differential signal; the output chopper modulates the noise and offset voltage of the transconductance amplifier to a chopping frequency, and modulates the amplified input differential signal back to a baseband; the output self-zeroing module receives an output signal of the output chopper and forms a feedback loop with the transconductance amplifier to finish fine self-zeroing operation; under the control of a clock signal CK0, the switches Sg1 and Sg2 provide common-mode voltage signals for the input ends INPP and INNP of the transconductance amplifier in the pre-charging stage.