14 results about "Chopper amplifier" patented technology

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).

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.

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.

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 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.