Amplifier and chip for suppressing noise

Abstract

The utility model provides a noise suppression amplifier which comprises a first instrument amplifier, a second instrument amplifier, a first filter and a second filter, the first instrument amplifier is electrically connected with the second instrument amplifier, and the second instrument amplifier is electrically connected with the first filter; and the second filter is arranged in the first instrument amplifier or the second instrument amplifier. On one hand, the second filter can perform primary filtering on the signal input into the second instrument amplifier, so that noise in the output signal of the second instrument amplifier is effectively reduced. And on the other hand, the signal input by the second instrument amplifier is filtered into the stable low-noise signal by the first-stage filter, so that the bandwidth of the first filter can be relatively large to ensure that the driving capability of the second instrument amplifier meets the design requirement.

Description

Technical Field

[0001] This application relates to the field of integrated circuit technology, and particularly to an amplifier and a chip for suppressing noise. Background Art

[0002] An instrumentation amplifier (INA), an improvement of a differential amplifier, has an input buffer and does not require input impedance matching, making the amplifier suitable for measurement and electronic instruments. In an instrumentation amplifier, noise sources are generated by the input terminal voltage, the output terminal voltage, and the gain resistors. Since the magnitude of the noise directly affects the accuracy of the acquisition by the instrumentation amplifier, the noise of the instrumentation amplifier needs to meet the preset ideal output noise during the design process. Therefore, how to suppress redundant noise of the instrumentation amplifier has become an urgent problem to be solved. Summary of the Utility Model

[0003] Embodiments of this application provide an amplifier for suppressing noise, which solves the technical problem that it is difficult to filter out the noise of the output signal when the filter bandwidth is too wide while ensuring the driving ability of the amplifier.

[0004] In a first aspect, some embodiments of this application provide an amplifier for suppressing noise, which includes a first instrumentation amplifier, a second instrumentation amplifier, a first filter, and a second filter. Among them, the first instrumentation amplifier is electrically connected to the second instrumentation amplifier, and the second instrumentation amplifier is electrically connected to the first filter; the second filter is disposed inside the first instrumentation amplifier or the second instrumentation amplifier.

[0005] In this way, on the one hand, the above-mentioned second filter can perform primary filtering on the signal input to the second instrumentation amplifier, suppress the noise of the output signal of the second instrumentation amplifier, and avoid the noise in the output signal of the first instrumentation amplifier being amplified and superimposed on the output signal of the second instrumentation amplifier, effectively reducing the noise in the output signal of the second instrumentation amplifier. On the other hand, the above-mentioned first filter can also perform secondary filtering on the signal output by the second instrumentation amplifier. Since the primary filtering filters the signal input to the second instrumentation amplifier into a stable low-noise signal, the bandwidth of the above-mentioned first filter can be relatively large to ensure that the driving ability of the second instrumentation amplifier meets the design requirements.

[0006] In some embodiments, the first instrumentation amplifier includes a first operational amplifier, a second operational amplifier, a compensation capacitor, and at least two gain resistors. Among them, the inverting connection terminal of the first operational amplifier and the inverting connection terminal of the second operational amplifier are connected in series through the compensation capacitor; at least two gain resistors are connected in series between the output terminal of the first operational amplifier and the output terminal of the second operational amplifier.

[0007] It can be understood that the above compensation capacitor can be used to compensate the voltage signal values output by the first operational amplifier and the second operational amplifier.

[0008] In some embodiments, the first instrumentation amplifier further includes a first chopper and a second chopper. The first chopper includes a first chopping switch, and the second chopper includes a second chopping switch. Among them, the first chopping switch is disposed at the input end of the first operational amplifier; the second chopping switch is disposed at the input end of the second operational amplifier.

[0009] It can be understood that the implementation of the above chopping technology can generate high-frequency noise.

[0010] In some embodiments, the second instrumentation amplifier is electrically connected to a first filter, including: the first filter is disposed at the output end of the second instrumentation amplifier.

[0011] In some embodiments, the second instrumentation amplifier further includes a third operational amplifier and at least two gain resistors, wherein the at least two gain resistors are connected in parallel with the operational amplifier feedback point and the output end of the third operational amplifier.

[0012] In some embodiments, the second instrumentation amplifier further includes a first input resistor and a second input resistor, wherein,

[0013] The first input resistor is connected in series between the second filter and the non-inverting input terminal of the third operational amplifier; the second input resistor is connected in series between the second filter and the inverting input terminal of the third operational amplifier.

[0014] In this way, the second filter can filter the signal input to the third operational amplifier, reducing the noise of the non-inverting output signal and the inverting output signal output by the third operational amplifier.

[0015] In some embodiments, the second filter includes a first filter resistor, a second filter resistor, and a filter capacitor. Among them, the first filter resistor is connected to the output end of the first operational amplifier; the second filter resistor is connected to the output end of the second operational amplifier; the first filter resistor is connected in series with the second filter resistor through the filter capacitor, and moreover, the first filter resistor is connected in series with the first input resistor, and the second filter resistor is connected in series with the second input resistor.

[0016] In some embodiments, the resistance values of the first filter resistor and the second filter resistor are equal, and the resistance values of the first input resistor and the second input resistor are equal.

[0017] In some embodiments, the sum of the resistance values of the first filter resistor and the first input resistor is equal to the sum of the resistance values of the second filter resistor and the second input resistor.

[0018] In some embodiments, the sum of the resistance values of the first filter resistor and the first input resistor is equal to the preset input resistance value of the second operational amplifier, and the sum of the resistance values of the second filter resistor and the second input resistor is equal to the preset input resistance value of the second operational amplifier.

[0019] In some embodiments, the capacitance value of the filter capacitor is greater than or equal to 30 pF.

[0020] In some embodiments, the capacitance value of the filter capacitor is greater than or equal to 30 pF and less than or equal to 40 pF.

[0021] A higher capacitance value of the filter capacitor is beneficial to isolating the operational amplifier feedback point VX of the second operational amplifier from the filter capacitor, thereby improving the loop stability of the second instrumentation amplifier.

[0022] In some embodiments, the first instrumentation amplifier includes a first gain resistor, a second gain resistor, and a third gain resistor, wherein the resistance values of the first gain resistor and the third gain resistor are equal.

[0023] Thus, the first gain resistor, the second gain resistor, and the third gain resistor can be used to determine the gain parameters of the first instrumentation amplifier. The equal resistance values of the first gain resistor and the third gain resistor can also ensure that the first instrumentation amplifier generates common-mode rejection, effectively suppressing common-mode signal interference, which is beneficial to forming an ideal differential output signal and suppressing common-mode signals.

[0024] In some embodiments, the first instrumentation amplifier includes any two of the first gain resistor, the second gain resistor, and the third gain resistor

[0025] In some embodiments, the second instrumentation amplifier includes a fourth gain resistor and a fifth gain resistor, wherein the fourth gain resistor includes a variable resistor, the fifth gain resistor includes a variable resistor, and the resistance value of the fourth gain resistor is equal to the resistance value of the fifth gain resistor.

[0026] Thus, common-mode signal interference can be effectively suppressed, which is beneficial to forming an ideal differential output signal and suppressing common-mode signals.

[0027] In a second aspect, the present application further provides a chip, which includes the amplifier according to any one of the first aspects above. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Shows a schematic connection structure diagram of an amplifier for suppressing noise;

[0029] Figure 2 Shows a schematic diagram of the device composition of an amplifier for suppressing noise in some embodiments of the present application;

[0030] Figure 3The schematic diagram of the internal circuit structure of each device of an amplifier for suppressing noise in some embodiments of the present application is shown;

[0031] Figure 4 The schematic diagram of splitting the input resistance of an operational amplifier in some embodiments of the present application is shown;

[0032] Figure 5 The block diagram of a system on chip (SoC) provided according to some embodiments of the present application is shown. Detailed implementation manners

[0033] To facilitate the understanding of the technical solutions provided in the embodiments of the present application, the meanings of some related field terms involved in the embodiments of the present application are explained below.

[0034] (1) Noise

[0035] Noise is an irregular signal, such as electromagnetic noise, thermal noise, radio transmission noise, laser noise, optical fiber communication noise, noise in the picture when a camera takes a picture, etc.

[0036] (2) Operational amplifier (OP AMP)

[0037] An operational amplifier is a circuit unit with a very high amplification factor. In an actual circuit, it is usually combined with a feedback network to form a certain functional module together. It is an amplifier with a special coupling circuit and feedback. Its output signal can be the result of mathematical operations such as addition, subtraction, differentiation, and integration of the input signal. Since it was early applied in analog computers to implement mathematical operations, it got the name "operational amplifier".

[0038] (3) Gain

[0039] Gain can be understood as the amplification factor. In electronics, it is usually the ratio of the signal output to the signal input of a system. In some embodiments, for example, the amplifier gain can be used to represent the power amplification factor of the amplifier, and can be represented by the common logarithm of the ratio of the output power to the input power.

[0040] (4) Chopper stabilization (CHS)

[0041] The principle of chopping technology is as follows: The input signal is modulated to a high frequency by the first chopper. The input signal modulated to a high frequency, the DC offset, and the input 1 / f noise are amplified by the amplifier at the same time. Then, the amplified input signal is restored by the second chopper, while the DC offset and the 1 / f noise are modulated to a high frequency. Therefore, the implementation of chopping technology can generate high-frequency noise. Furthermore, when applying the above chopping technology, there is a need to filter out the noise and offset modulated to a high frequency.

[0042] (5) Low-pass filter (LF)

[0043] A low-pass filter is an electronic filtering device that can pass signals below the cut-off frequency and filter out signals above the cut-off frequency. In some embodiments, a resistor-capacitor (RC) low-pass filter can be constructed by connecting a resistor in series with the signal path and a capacitor in parallel with the load to produce a resistor-capacitor low-pass response.

[0044] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions provided by the embodiments of the present application will be described in detail below in conjunction with the accompanying drawings of the specification and specific implementation manners.

[0045] Figure 1 A schematic connection structure diagram of an amplifier 10 for suppressing noise is shown. The amplifier 10 includes a first instrumentation amplifier 100, a second instrumentation amplifier 200, and a filter 300. The above-mentioned first instrumentation amplifier 100 (hereinafter referred to as PGA100) receives the common-mode input voltage VIP and the differential input voltage VIN. PGA 100 amplifies VIP to obtain the first common-mode output voltage VOP1, and PGA 100 amplifies VIN to obtain the second differential output voltage VON1. PGA 100 inputs the first common-mode output voltage VOP1 and the second differential output voltage VON1 to the second instrumentation amplifier 200 (hereinafter referred to as PGA 200).

[0046] It can be understood that the above-mentioned PGA 200 amplifies the first output voltage VOP1, and after filtering by the filter 300, the third output voltage VON is obtained. And, PGA 200 amplifies the second output voltage VON1, and after filtering by the filter 300, the fourth output voltage VOP is obtained. Furthermore, the first output voltage VOP1 and the second output voltage VON1 output by PGA 100 can be smoothed and filtered by PGA 200 and the filter 300 to reduce the noise generated by PGA 100 amplifying the input voltage.

[0047] It can be understood that the noise generated in the PGA 100 will be amplified by the PGA 200 and superimposed on the output voltage. Therefore, the PGA 200 can filter the noise in the output voltage through the filter 300. However, when the resistance value set in the filter is relatively high, the processing speed of the PGA 200 cannot reach the expected value. For example, under a fixed capacitive load, due to the high resistance value of the filter 300, the bandwidth of the filter 300 is low. This will cause the accuracy of the PGA 200 not to reach the preset accuracy within the preset time, and at this time, the driving ability of the PGA 200 is insufficient. Therefore, in order to ensure the driving ability of the PGA 200, the bandwidth of the filter 300 needs to be widened, making the noise of the output signal larger.

[0048] In order to solve the technical problem that it is difficult to filter the noise of the output signal when the filter bandwidth is too wide while ensuring the driving ability of the amplifier, the present application proposes an amplifier for suppressing noise. The amplifier includes a first instrumentation amplifier, a second instrumentation amplifier, a first filter, and a second filter. Among them, the second filter is disposed inside the first instrumentation amplifier or the second instrumentation amplifier and is used for filtering the output signal of the first instrumentation amplifier; the first filter is used for filtering the output signal of the second instrumentation amplifier. Thus, on the one hand, the above-mentioned second filter can perform primary filtering on the signal input to the second instrumentation amplifier, suppress the noise of the output signal of the second instrumentation amplifier, and prevent the noise in the output signal of the first instrumentation amplifier from being amplified and superimposed on the output signal of the second instrumentation amplifier, effectively reducing the noise in the output signal of the second instrumentation amplifier. On the other hand, the above-mentioned first filter can also perform secondary filtering on the signal output by the second instrumentation amplifier. Since the primary filtering filters the signal input to the second instrumentation amplifier into a stable low-noise signal, the bandwidth of the above-mentioned first filter can be relatively large to ensure that the driving ability of the second instrumentation amplifier meets the design requirements.

[0049] The following will describe in detail an amplifier for suppressing noise in some embodiments of the present application with reference to the relevant drawings.

[0050] Figure 2 The schematic diagram of the device composition of an amplifier for suppressing noise in some embodiments of the present application is shown.

[0051] Referring to Figure 2 , the above-mentioned amplifier 20 for suppressing noise may include a first instrumentation amplifier 100 (or PGA 100), a second instrumentation amplifier 200 (or PGA 200), and a first filter 300. Among them, the first instrumentation amplifier 100 is electrically connected to the second instrumentation amplifier 200, and the second instrumentation amplifier 200 is electrically connected to the first filter 300. The first filter 300 is used for filtering the output signal of the second instrumentation amplifier 200.

[0052] The second instrumentation amplifier 200 further includes a second filter 201, which is disposed at the input end of the second instrumentation amplifier 200 and is used for performing primary filtering on the first non-inverting output voltage VOP1 and the first inverting output voltage VON2 output from the first instrumentation amplifier 100 to the second instrumentation amplifier 200. In some other embodiments, the second filter 201 may also be disposed at the output end of the first instrumentation amplifier 100 for performing primary filtering on the first non-inverting output voltage VOP1 and the first inverting output voltage VON2 output from the first instrumentation amplifier 100, and this is not limited herein.

[0053] In this way, an increase in the noise of the input signal output by the second instrumentation amplifier can be suppressed, and the noise in the output signal of the first instrumentation amplifier can be prevented from being amplified and superimposed on the output signal of the second instrumentation amplifier.

[0054] Next, in conjunction with Figure 3 the internal circuit structures of the components of an amplifier 20 for suppressing noise in some embodiments of the present application will be described in detail.

[0055] Referring to Figure 3 , the amplifier 20 includes a first instrumentation amplifier 100 and a second instrumentation amplifier 200.

[0056] Exemplarily, the first instrumentation amplifier 100 includes a first operational amplifier 101, a second operational amplifier 102, a compensation capacitor 103, a first gain resistor 104, a second gain resistor 105, and a third gain resistor 106. Among them, the above-mentioned first operational amplifier 101 and second operational amplifier 102 can be regarded as buffers, and the first gain resistor 104, the second gain resistor 105, and the third gain resistor 106 are connected in series for calculating the gain of the first instrumentation amplifier 100. The total resistance formed by the series connection of the above-mentioned gain resistors is disposed between the output end of the first operational amplifier 101 and the output end of the second operational amplifier 102. In some other embodiments, the first instrumentation amplifier 100 may also include two gain resistors, for example, any two of the first gain resistor 104, the second gain resistor 105, and the third gain resistor 106.

[0057] That is to say, the first instrumentation amplifier 100 may include at least two gain resistors, and the at least two gain resistors are connected in series between the output end of the first operational amplifier and the output end of the second operational amplifier.

[0058] In some embodiments, a first non-inverting input voltage VIP is input to the non-inverting input terminal of the first operational amplifier 101, a first inverting input voltage VIN is input to the inverting input terminal of the first operational amplifier 101, and a compensation capacitor 103 is connected in series between the inverting input terminal of the first operational amplifier 101 and the inverting input terminal of the second operational amplifier 102. A first gain resistor 104, a second gain resistor 105, and a third gain resistor 106 are connected in series between the output terminal of the first operational amplifier 101 and the output terminal of the second operational amplifier 102.

[0059] It can be understood that, in order to ensure the operational stability of the entire amplifier, it is necessary to make the first non-inverting output voltage VOP1 output by the first operational amplifier 101 the same as the first inverting output voltage VON1. Therefore, the above compensation capacitor 101 can be used to perform phase compensation on the first non-inverting output voltage VOP1 and the first inverting output voltage VON1.

[0060] It can be understood that the above first gain resistor 104, second gain resistor 105, and third gain resistor 106 can be used to determine the gain parameters of the first instrumentation amplifier 100. For example, the gain parameters of the first instrumentation amplifier 100 are:

[0061]

[0062] In some embodiments, the resistance values of the above first gain resistor 104 and third gain resistor 106 are equal to ensure that the first instrumentation amplifier 100 generates common-mode rejection, effectively suppresses common-mode signal interference, and is beneficial to forming an ideal differential output signal and suppressing common-mode signals.

[0063] In some embodiments, chopper technology can be used at the input terminals of the first operational amplifier 101 and the second operational amplifier 102 to improve the noise reduction effect. For example, referring to Figure 3 , the first chopper can include a first chopper switch 107, and the chopper switch 107 can be disposed at the input terminal of the first operational amplifier 101; the second chopper can include a second chopper switch 108, and the second chopper switch 108 can be disposed at the input terminal of the second operational amplifier 102. It can be understood that the principle of chopping is as follows: the input signal is modulated to a high frequency by the first chopper, and the input signal modulated to the high frequency, the DC offset, and the input 1 / f noise are simultaneously amplified by the amplifier. Then, the amplified input signal is restored by the second chopper, while the DC offset and the 1 / f noise are modulated to a high frequency. Therefore, the implementation of chopper technology can generate high-frequency noise.

[0064] For example, a chopping clock signal CLK_CHOP is input between a first operational amplifier 101 and a second operational amplifier 102. The chopping clock signal CLK_CHOP is the clock signal required for the operation of the above-mentioned first chopper and second chopper. The chopping clock signal CLK_CHOP can be a square wave signal, including two indication signals of a high level and a low level. Referring to the figure Subsequently, the first operational amplifier 101 and the second operational amplifier 102 can synchronously perform commutation switching on the input voltage signal through the above-mentioned chopping clock signal CLK_CHOP, and can mark a single commutation switching process by performing a high-low level exchange on the chopping signals of the non-inverting input terminal and the inverting input terminal, so as to realize the phase switching of the output signals at the output terminals of the first operational amplifier 101 and the second operational amplifier 102. Then, the signal output by the first instrumentation amplifier 100 will include high-frequency noise with the same frequency as the chopping clock signal CLK_CHOP. That is to say, the first non-inverting output voltage V0P1 and the first inverting output voltage VON1 include high-frequency noise. Furthermore, when applying the above-mentioned chopping technology, there is a need to filter out the noise and offset modulated to high frequencies. Thus, the amplitude of the noise included in the first non-inverting output voltage VOP1 output by the first operational amplifier 101 and the first inverting output voltage VON1 output by the second operational amplifier 102 will be amplified to a relatively large value, such as 2 megahertz, so as to facilitate filtering by a low-pass filter and facilitate subsequent noise reduction processing.

[0065] Continuing to refer to Figure 3 , the second instrumentation amplifier 200 includes a fourth gain resistor 204, a fifth gain resistor 205, and a third operational amplifier 206.

[0066] Among them, the fourth gain resistor 204 and the fifth gain resistor 205 can be used to determine the gain parameter of the second instrumentation amplifier 200. For example, the gain parameter of the second instrumentation amplifier 200 can be:

[0067] In some embodiments, the fourth gain resistor 204 and the fifth gain resistor 205 can be adjustable resistors, so that the gain of the second instrumentation amplifier 200 can be freely adjusted based on the amplification requirement.

[0068] In some embodiments, the resistance values of the fourth gain resistor 204 and the fifth gain resistor 205 are equal.

[0069] It can be understood that the specific resistance values of the fourth gain resistor 204 and the fifth gain resistor 205 can be specifically set based on the specific gain of the second instrumentation amplifier 200, and the number of the above gain resistors can also be specifically set based on the specific gain of the second instrumentation amplifier 200, which is not limited herein. For example, in some other embodiments, the second instrumentation amplifier 200 may also include more than two gain resistors.

[0070] It can be understood that at least two gain resistors included in the second instrumentation amplifier 200 may be connected in parallel with the operational amplifier feedback point VX and the output terminal (VOP or VON) of the third operational amplifier.

[0071] Continuing to refer to the Figure 3 above, the second instrumentation amplifier 200 further includes a second filter 201, a first input resistor 012, and a second input resistor 014. The second filter 201 and the first input resistor 012 are connected in series to the non-inverting input terminal of the third operational amplifier 206, and the second filter 201 and the second input resistor 014 are connected in series to the inverting input terminal of the third operational amplifier 206. In this way, the second filter 201 can filter the signal input to the third operational amplifier 206, reducing the noise of the non-inverting output signal and the inverting output signal output by the third operational amplifier 206. As described above, the second filter 201 may also be provided, for example, at the output terminal within the first instrumentation amplifier 101, which is not limited herein.

[0072] In some embodiments, the second filter 201 further includes a first filter resistor 011, a second filter resistor 013, and a filter capacitor 015. Among them, the first filter resistor 011 is connected to the output terminal of the first operational amplifier 101, and the second filter resistor 013 is connected to the output terminal of the second operational amplifier. The filter capacitor 015 is connected in series between the first filter resistor 011 and the second filter resistor 013, or rather, the first filter resistor 011 is connected in series with the second filter resistor 013 through the filter capacitor 015, forming a resistor-capacitor filter, which can be used for low-pass filtering of the signal input to the third operational amplifier 206. Moreover, the first filter resistor 011 is connected in series with the first input resistor 012, and the second filter resistor 013 is connected in series with the second input resistor 014.

[0073] It can be understood that the above low-pass filtering process includes but is not limited to smoothing filtering.

[0074] In some embodiments, the capacitance value of the above-mentioned filtering capacitor 015 can be greater than a preset threshold. For example, it can be greater than or equal to 30 picofarads (pF), or for another example, it can be greater than or equal to 30 pF and less than or equal to 40 pF. Since the capacitance value of the filtering capacitor 015 is relatively high, the above-mentioned first input resistor 012 and second input resistor 014 can isolate the operational amplifier feedback point VX of the second operational amplifier from the filtering capacitor 015, thereby improving the loop stability of the second instrumentation amplifier 200.

[0075] It can be understood that the above-mentioned preset threshold can be freely set according to the actual usage requirements of the amplifier, and no limitation is made here.

[0076] In some embodiments, the resistance values of the first filtering resistor 011 and the second filtering resistor 013 are equal, the resistance values of the first input resistor 012 and the second input resistor 014 are equal, and the resistance values of the fourth gain resistor 204 and the fifth gain resistor 205 are equal. Thereby effectively suppressing the common-mode signal interference, which is beneficial to forming an ideal differential output signal and suppressing the common-mode signal.

[0077] It can be understood that the sum of the resistance values of the first filtering resistor 011 and the first input resistor 012 is equal to the sum of the resistance values of the second filtering resistor 013 and the second input resistor 014. In still other embodiments, the resistance values of the first filtering resistor 011 and the first input resistor 012 can also be equal, and the resistance values of the second filtering resistor 013 and the second input resistor 014 can also be equal, and no limitation is made here. In this way, the first filtering resistor 011 and the first input resistor 012 can be equivalent to an input resistor with a resistance value twice that of the first filtering resistor 011, and the second filtering resistor 013 and the second input resistor 014 can be equivalent to an input resistor with a resistance value twice that of the second filtering resistor 013.

[0078] It can be understood that the sum of the resistance values of the above-mentioned first filtering resistor and the first input resistor can be equal to the preset input resistance value of the second operational amplifier, and the sum of the resistance values of the second filtering resistor and the second input resistor can be equal to the preset input resistance value of the second operational amplifier.

[0079] Reference Figure 4 , R1 and R2 in X can be the original input resistors of the second instrumentation amplifier 200. If the input resistor at the non-inverting input terminal of the operational amplifier in X is split into two resistors with a resistance value of and the input resistor at the inverting input terminal of the operational amplifier in X is split into two resistors with a resistance value of The resistors can be split, and the split input resistors in Y are respectively connected to the non-inverting input terminal and the inverting input terminal of the operational amplifier. It can be understood that performing the above splitting process on the input resistors will not affect the original gain of the second instrumentation amplifier 200. Therefore, the sum of the resistance values of the first filter resistor 011 and the first input resistor 012 can be made equal to the resistance value of the input resistor of the second instrumentation amplifier 200, and the sum of the resistance values of the second filter resistor 013 and the second input resistor 014 can be made equal to the resistance value of the input resistor of the second instrumentation amplifier 200. Thus, the second filter 201 can be constructed without affecting the original gain of the second instrumentation amplifier 200. Moreover, the first input resistor 012 and the second input resistor 014 can isolate the operational amplifier feedback point VX of the second operational amplifier from the filter capacitor 015, thereby improving the loop stability of the second instrumentation amplifier 200.

[0080] In some embodiments, the above second filter 201 can be constructed by leveraging the position of the original input resistor of the second instrumentation amplifier 200 to reduce the area occupied by the second filter 201 on the chip wafer, thereby effectively reducing the chip manufacturing cost.

[0081] In some embodiments, an amplifier for suppressing noise described above can be disposed on a chip, such as a system on chip (SoC).

[0082] The following combines Figure 5 to provide a detailed description of a system on chip (SoC) according to some embodiments of the present application.

[0083] Figure 5 FIG. shows a block diagram of a system on chip (SoC) according to some embodiments of the present application. In Figure 5 , similar components have the same reference numerals. Additionally, the dashed boxes are optional features of a more advanced SoC. In Figure 5 , the SoC 500 includes: an interconnect unit 550, which is coupled to a processor 515; a system agent unit 570; a bus controller unit 580; an integrated memory controller unit 540; one or a group of coprocessors 520, which may include integrated graphics logic, an image processor, an audio processor, and a video processor; an SRAM unit 530; a direct memory access (DMA) unit 560. In one embodiment, the coprocessor 520 includes a dedicated processor, such as, for example, a network or communication processor, a compression engine, a GPGPU, a high-throughput MIC processor, or an embedded processor, etc.

[0084] Embodiments of the mechanisms disclosed in this application may be implemented in hardware, software, firmware, or a combination of these implementation methods. Embodiments of this application may be implemented as a computer program or program code executed on a programmable system, which includes at least one processor, a storage system (including volatile and non-volatile memories and / or storage elements), at least one input device, and at least one output device.

[0085] The program code may be applied to the input instructions to perform the various functions described in this application and generate output information. The output information may be applied to one or more output devices in a known manner. For the purposes of this application, a processing system includes any system having a processor such as, for example, a digital signal processor (DSP), a microcontroller, an application specific integrated circuit (ASIC), or a microprocessor.

[0086] The program code may be implemented in a high-level procedural language or an object-oriented programming language in order to communicate with the processing system. When necessary, the program code may also be implemented in assembly language or machine language. In fact, the mechanisms described in this application are not limited to the scope of any specific programming language. In any case, the language may be a compiled language or an interpreted language.

[0087] In some cases, the disclosed embodiments may be implemented in hardware, firmware, software, or any combination thereof. The disclosed embodiments may also be implemented as instructions carried or stored on one or more transient or non-transient machine-readable (e.g., computer-readable) storage media, which may be read and executed by one or more processors. For example, the instructions may be distributed via a network or via other computer-readable media. Thus, machine-readable media may include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computer), including but not limited to, floppy disks, optical disks, optical discs, compact disc read-only memories (CD-ROMs), magneto-optical discs, read only memory (ROM), random access memory (RAM), erasable programmable read only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic or optical cards, flash memory, or tangible machine-readable memories for transmitting information (e.g., carrier waves, infrared signals, digital signals, etc.) in electrical, optical, acoustic, or other forms via the Internet. Thus, machine-readable media include any type of machine-readable media suitable for storing or transmitting electronic instructions or information in a form readable by a machine (e.g., a computer).

[0088] In the drawings, some structural or method features may be shown in a particular arrangement and / or order. However, it should be understood that such a particular arrangement and / or ordering may not be required. Rather, in some embodiments, these features may be arranged in a manner and / or order different from that shown in the illustrative drawings. Additionally, the inclusion of a structural or method feature in a particular figure does not imply that such a feature is required in all embodiments, and in some embodiments, these features may not be included or may be combined with other features.

[0089] It should be noted that each unit / module mentioned in the device embodiments of this application is a logical unit / module. Physically, a logical unit / module may be a physical unit / module, a part of a physical unit / module, or may be implemented as a combination of multiple physical units / module. The physical implementation manner of these logical units / module themselves is not the most important. The combination of the functions implemented by these logical units / module is the key to solving the technical problems proposed in this application. In addition, to highlight the innovative part of this application, the above device embodiments of this application do not introduce units / modules that are not closely related to solving the technical problems proposed in this application, which does not mean that there are no other units / modules in the above device embodiments.

[0090] It should be noted that in the examples and description of this patent, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising one" does not exclude the presence of additional identical elements in the process, method, article or device comprising such element.

[0091] Although this application has been illustrated and described by reference to certain embodiments thereof, those of ordinary skill in the art should understand that various changes may be made thereto in form and detail without departing from the spirit and scope of this application.

Claims

1. A noise suppression amplifier, characterized in that: The amplifier includes a first instrumentation amplifier, a second instrumentation amplifier, a first filter, and a second filter, wherein: The first instrument amplifier is electrically connected to the second instrument amplifier, and the second instrument amplifier is electrically connected to the first filter; The second filter is arranged inside the first instrument amplifier or the second instrument amplifier.

2. The amplifier according to claim 1, characterized in that The first instrumentation amplifier includes a first operational amplifier, a second operational amplifier, a compensation capacitor and at least two gain resistors, wherein: The inverting connection terminal of the first operational amplifier and the inverting connection terminal of the second operational amplifier are connected in series via the compensation capacitor; The at least two gain resistors are arranged in series between the output terminal of the first operational amplifier and the output terminal of the second operational amplifier.

3. The amplifier according to claim 2, characterized in that The first instrumentation amplifier further includes a first chopper and a second chopper, the first chopper includes a first chopper switch, the second chopper includes a second chopper switch, wherein, The first chopper switch is arranged at the input end of the first operational amplifier; The second chopping switch is arranged at the input end of the second operational amplifier.

4. The amplifier according to claim 1, characterized in that The second instrument amplifier is electrically connected to the first filter, and includes: The first filter is arranged at the output end of the second instrument amplifier.

5. The amplifier according to claim 2, characterized in that The second instrumentation amplifier further includes a third operational amplifier and at least two gain resistors, wherein: The at least two gain resistors are connected in parallel with an operational amplifier feedback point and an output terminal of the third operational amplifier.

6. The amplifier according to claim 5, characterized in that The second instrumentation amplifier further includes a first input resistor and a second input resistor, wherein: The first input resistor is connected in series between the second filter and the non-inverting input terminal of the third operational amplifier; The second input resistor is connected in series between the second filter and the inverting input terminal of the third operational amplifier.

7. The amplifier according to claim 6, characterized in that The second filter comprises a first filter resistor, a second filter resistor and a filter capacitor, wherein: The first filter resistor is connected to the output end of the first operational amplifier; The second filter resistor is connected to the output end of the second operational amplifier; The first filter resistor is connected in series with the second filter resistor via the filter capacitor, and the first filter resistor is connected in series with the first input resistor, and the second filter resistor is connected in series with the second input resistor.

8. The amplifier according to claim 7, characterized in that The resistance values ​​of the first filter resistor and the second filter resistor are equal, and the resistance values ​​of the first input resistor and the second input resistor are equal.

9. The amplifier according to claim 6, characterized in that The sum of the resistance values ​​of the first filter resistor and the first input resistor is equal to the sum of the resistance values ​​of the second filter resistor and the second input resistor.

10. The amplifier according to claim 9, characterized in that The sum of the resistance values ​​of the first filter resistor and the first input resistor is equal to the preset input resistance value of the second operational amplifier, and the sum of the resistance values ​​of the second filter resistor and the second input resistor is equal to the preset input resistance value of the second operational amplifier.

11. The amplifier according to claim 5, characterized in that The capacitance of the filter capacitor is greater than or equal to 30pF.

12. The amplifier according to claim 11, characterized in that The capacitance of the filter capacitor is greater than or equal to 30 pF and less than or equal to 40 pF.

13. The amplifier according to claim 2, characterized in that The first instrument amplifier includes a first gain resistor, a second gain resistor and a third gain resistor, wherein: The resistance value of the first gain resistor is equal to the resistance value of the third gain resistor.

14. The amplifier according to claim 2, characterized in that The first instrumentation amplifier includes any two resistors among a first gain resistor, a second gain resistor and a third gain resistor.

15. The amplifier according to claim 5, characterized in that The second instrumentation amplifier includes a fourth gain resistor and a fifth gain resistor, wherein the fourth gain resistor includes an adjustable resistor, the fifth gain resistor includes an adjustable resistor, and, The resistance value of the fourth gain resistor is equal to the resistance value of the fifth gain resistor.

16. A chip, characterized in that: The chip comprises the amplifier according to any one of claims 1 to 15.

Images