WO2023040699A1 - Signal amplification circuit and chip - Google Patents
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- WO2023040699A1 WO2023040699A1 PCT/CN2022/117138 CN2022117138W WO2023040699A1 WO 2023040699 A1 WO2023040699 A1 WO 2023040699A1 CN 2022117138 W CN2022117138 W CN 2022117138W WO 2023040699 A1 WO2023040699 A1 WO 2023040699A1
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/68—Combinations of amplifiers, e.g. multi-channel amplifiers for stereophonics
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03G—CONTROL OF AMPLIFICATION
- H03G3/00—Gain control in amplifiers or frequency changers
- H03G3/20—Automatic control
- H03G3/30—Automatic control in amplifiers having semiconductor devices
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
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- the electrodermal signal is very weak, it is difficult to be identified without amplification processing, and various vital signs and activities of the human body will produce different electrodermal signals, which can be easily identified after processing, and then use these processing in the future
- the obtained data can be used in various applications.
- it can be applied to the field of bioelectric signal collection, such as the medical field and the field of wearable electronic devices.
- An object of the embodiments of the present disclosure is to provide a new technical solution for a signal amplifying circuit and a chip.
- a beneficial effect of the embodiment of the present disclosure is that this embodiment adopts a first-stage amplifying circuit with an instrumentation amplifier and a second-stage amplifying circuit with an operational amplifier, and utilizes the characteristics of high input impedance and high common-mode rejection ratio of the instrumentation amplifier to be able to It has a better signal amplification effect.
- Fig. 2 is the circuit structure of the primary amplifier circuit provided by the present embodiment
- Fig. 4 is a circuit diagram of the first filtering circuit provided by the present embodiment.
- Fig. 5 is the circuit diagram of the secondary amplification circuit provided by the present embodiment.
- FIG. 6 is a reference diagram of the magnification factor relationship of the secondary amplifier circuit provided in this embodiment.
- the present embodiment provides a kind of signal amplifying circuit, comprises: one-stage amplifying circuit 101, two-stage amplifying circuit 102 and signal conversion circuit 103, one-stage amplifying circuit 101 is provided with first signal input terminal J1, second signal The input terminal J2, the first signal input terminal J1 and the second signal input terminal J2 are used for collecting detection signals.
- the primary amplification circuit 101 is used for primary amplification of the received detection signal
- the secondary amplification circuit 102 is used for secondary amplification of the received detection signal
- the signal conversion circuit is used for performing secondary amplification according to the amplified secondary amplified signal. Algorithm operation, and then identify the information that needs to be identified in the electrodermal signal.
- the first signal input terminal J1 and the second signal input terminal J2 can be two metal electrodes, and the metal electrodes corresponding to the first signal input terminal J1 and the second signal input terminal J2 are placed close to the skin to form a circuit to realize electrodermal signal delivery and collection.
- the primary amplification circuit 101 receives the detection signal, and after performing primary amplification on the received detection signal, outputs the signal after the primary amplification to the secondary amplification circuit 102, and the secondary amplification circuit 102 amplifies the signal after the primary amplification. Perform secondary amplification and output to the signal conversion circuit 103.
- the signal conversion circuit 103 performs algorithmic calculations based on the secondary amplified signal, and then recognizes the information that needs to be recognized in the electrodermal signal.
- the signal conversion circuit 103 includes an analog-to-digital converter ADC, the first end of the analog-to-digital converter ADC is used to receive the secondary amplified signal, and the second end of the analog-to-digital converter ADC is used to convert the received secondary After the amplified signal undergoes analog-to-digital conversion, the digital signal of the secondary amplified signal is output.
- ADC analog-to-digital converter ADC
- the circuit in this embodiment is designed for small signal circuits, therefore, the frequency of the circuit detection signal is less than 1 KHz.
- the detection signal can be a low-frequency small signal on the skin surface, which can be generated by the veins on the skin surface or the micro-current of the skin itself.
- the amplitude of the electrical signal on the skin surface is in the range of 0-5mV, generally It is about 1mV.
- the instrumentation amplifier superimposes the differential voltage signals VF1 and VF2 with the reference voltage VMID respectively, and combines the gain Q1 to obtain the amplified single-ended signal V1, which is the third terminal output V1 of the instrumentation amplifier, and completes the first stage enlarge.
- the signal strength is relatively weak, generally 1mV, and the instrumentation amplifier has a poor recognition effect on the input signal. Therefore, a differential voltage greater than the skin signal is used
- the signal transmits the skin signal, for example, the skin signal is transmitted by using differential voltage signals VF1 and VF2, and the voltage value of VF1 and VF2 may be 5mV.
- the differential voltage signal can also resist signal interference except the input signals of the first signal input terminal J1 and the second signal input terminal J2.
- the gain of the instrumentation amplifier is Q1
- the reference voltage VMID can be determined according to the performance of the instrumentation amplifier, for example, the reference voltage VMID is 2.5V. Since the input signals of the first signal input terminal J1 and the second signal input terminal J2 are analog signals, the reference voltage VMID of 2.5V is used as the carrier to realize the instrumentation amplifier to amplify the skin signal to obtain an amplified single-ended signal V1.
- the gain of the instrumentation amplifier is adjusted through the first gain adjustment circuit.
- the first gain adjustment circuit includes a first gain control terminal INA-A0, a second gain control terminal INA-A1 and a third gain control terminal INA- A2, the first gain control terminal, the second gain control terminal and the third gain control terminal are connected to the instrumentation amplifier through different connection pins of the instrumentation amplifier. For example, different pins A0, A1, A2 of the instrumentation amplifier in Fig. 2 are respectively connected to INA-A0, INA-A1, INA-A2.
- the amplification factor Q1 of the primary amplifier circuit is adjusted.
- the relationship between the level configuration of the first gain control terminal INA-A0, the second gain control terminal INA-A1 and the third gain control terminal INA-A2 and the amplification factor of the first-stage amplifier circuit is referred to FIG. 3 .
- the primary amplifying circuit 101 is also provided with a voltage dividing resistor and a filter capacitor, such as the voltage dividing resistor R17 in FIG. Capacitor C1 is connected to the power supply VS terminal of the instrumentation amplifier.
- the circuit further includes a first filter circuit 104 for filtering the primary amplified signal, the first terminal of the first filter circuit 104 is connected to the third terminal of the instrumentation amplifier U1A The second end of the first filter circuit 104 is connected to the first end of the operational amplifier U1B.
- FIG. 5 is a circuit diagram of the secondary amplifying circuit 102, the secondary amplifying circuit 102 includes an operational amplifier U1B, and the first end of the operational amplifier U1B is used to receive the filtered primary amplified signal V2, and perform the operation
- the amplifier U1B is used to generate a second-stage amplified signal according to the first-stage amplified signal, and the second terminal of the operational amplifier is used to output the second-stage amplified signal V3.
- the secondary amplifier circuit 102 also includes a second gain adjustment circuit 106, the first end of the second gain adjustment circuit 106 is connected to the second end of the operational amplifier, and the second end of the second gain adjustment circuit 106 is connected to the operational amplifier.
- the third terminal of the amplifier is connected to the second end of the operational amplifier.
- the second gain adjustment circuit includes a first resistor R7, a switch circuit U2, a second resistor R5 and a third resistor R8, and the second resistor R5 and the third resistor R8 are respectively connected to switches on different branches of the switch circuit U2
- the switch circuit U2 has two different branches, each branch is provided with a switch, then the second resistor R5 is connected to the switch on one branch of the switch circuit U2, and the third resistor R8 is connected to the switch circuit A switch on the other branch of U2.
- the switch circuit U2 has two different branches, each branch is provided with a switch, then the second resistor R5 is connected to the switch on one branch of the switch circuit U2, and the third resistor R8 is connected to the switch circuit A switch on the other branch of U2.
- the switch circuit U2 is provided with a first switch component COM1 and a second switch component COM2, and the first switch component COM1 and the second switch component COM2 are respectively located on switch components on different branches.
- the first end is at the same potential as the first end of the second switch COM2, the second end of the first switch COM1 is connected to the second resistor R5, and the second end of the second switch COM2 is connected to the third resistor R8.
- the first resistor R7 is connected in parallel with the circuit formed by the switch circuit U2, the second resistor R5 and the third resistor R8.
- the second gain adjustment circuit is also connected with a reference voltage VMID for providing a reference voltage for the second gain adjustment circuit, wherein the second gain adjustment circuit is also provided with a filter capacitor C5, and the filter capacitor C5 is connected in parallel with the first resistor R7 .
- the output signal V2 of the band-pass filter is input to the terminal of the operational amplifier U1B, and after two stages of amplification, the amplification factor Q2 is determined by the primary amplification factor Q1, the switch circuit U2 and peripheral circuits.
- the input terminal of the switch circuit includes a first gain control terminal BIO_LF_GAINS1 and a second gain control terminal BIO_LF_GAINS2.
- the first gain control terminal and the second gain control terminal are used to input high and low levels.
- the level of BIO_LF_GAINS1 and the second gain control terminal BIO_LF_GAINS2 controls the on-off of the first switching element COM1 and the second switching element COM2, thereby controlling the total resistance in the access circuit to adjust the amplification factor Q2 of the secondary amplifier circuit , to obtain two-stage amplifier circuits with different magnifications.
- FIG. 6 for the amplification factor of the secondary amplifier circuit.
- the secondary amplifier circuit when the first gain control terminal BIO_LF_GAINS1 and the second gain control terminal BIO_LF_GAINS2 are both at low levels, the secondary amplifier circuit’s amplification factor Q2 is equal to 182Q1; when BIO_LF_GAINS1 is High level, when BIO_LF_GAINS2 is low level, Q2 is equal to 76Q1; when BIO_LF_GAINS1 is low level, when BIO_LF_GAINS2 is high level, Q2 is equal to 56Q1; when both BIO_LF_GAINS1 and BIO_LF_GAINS2 are high level, Q2 is equal to 39Q1.
- the circuit also includes a second filter circuit 105 for filtering the secondary amplified signal, the first end of the second filter circuit 105 is connected to the second end of the operational amplifier, and the second end of the second filter circuit 105 The second terminal is connected with the first terminal of the analog-to-digital converter.
- the second filter circuit is a low-pass filter composed of a sixth resistor R28 and a third filter capacitor C18, one end of the sixth resistor is connected to the signal output terminal of the operational amplifier, and the third filter capacitor is connected to The first side of the analog-to-digital converter.
- the input voltage of the low-pass filter is V3, and the output voltage is V4.
- the signal conversion circuit includes an analog-to-digital converter, the first end of the analog-to-digital converter U5 is used to receive the secondary amplified signal, and the first end of the analog-to-digital converter is used to output a digital signal based on the secondary amplified signal .
- the digital signal can be input to the main control chip through the communication bus interface, and the algorithm operation is performed, and then the information that needs to be identified can be identified such as the electrodermal signal.
- the signal conversion circuit further includes a voltage input terminal for providing a DC voltage and an AC voltage to the analog-to-digital converter, wherein the AC voltage input terminal ANA is connected to the AC pin AVDD of the analog-to-digital converter, and the DC voltage input terminal V1P8 It is connected to the DC pin DVDD of the analog-to-digital converter, and the AC voltage input terminal ANA is also connected to the driving terminal REF of the analog-to-digital converter.
- a driving resistor R27 and a voltage dividing resistor R30 are provided on the driving circuit between the AC voltage input terminal ANA and the driving terminal REF of the analog-to-digital converter.
- the AC voltage input terminal ANA is connected with filter capacitors C15 and C16, and the DC voltage input terminal V1P8 is connected with a filter capacitor C17.
- This embodiment adopts a primary amplifying circuit with an instrumentation amplifier and a secondary amplifying circuit with an operational amplifier, and utilizes the characteristics of high input impedance and high common-mode rejection ratio of the instrumentation amplifier to have a better signal amplification effect; and a The respective gains of the first-stage amplifier circuit and the first-stage amplifier circuit can be adjusted, making it more flexible to use.
- This embodiment utilizes the characteristics of high input impedance and high common-mode rejection ratio of the instrumentation amplifier to have a better signal amplification effect, and the primary amplifier circuit and the secondary amplifier circuit are packaged in one chip, which can be used in circuit design. Save space.
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Abstract
A signal amplification circuit and a chip, relating to the technical field of signal processing, and comprising: a first-stage amplification circuit (101), a second-stage amplification circuit (102) and a signal conversion circuit (103). The first-stage amplification circuit (101) comprises a first signal input terminal (J1), a second signal input terminal (J2) and an instrumentation amplifier (U1A); the first signal input terminal (J1) and the second signal input terminal (J2) are respectively connected to a first terminal and a second terminal of the instrumentation amplifier (U1A); the first signal input terminal (J1) and the second signal input terminal (J2) are configured to acquire a detection signal; the instrumentation amplifier (U1A) is configured to generate a first-level amplified signal according to the detection signal; the second-stage amplification circuit (102) comprises an operational amplifier (U1B); a first end of the operational amplifier (U1B) is configured to receive the first-stage amplified signal; the operational amplifier (U1B) is configured to generate a second-stage amplified signal according to the first-stage amplified signal; the signal conversion circuit (103) comprises an analog-to-digital converter (ADC); a first end of the analog-to-digital converter (ADC) is configured to receive the second-stage amplified signal; a second end of the analog-to-digital converter (ADC) is configured to output a digital signal on the basis of the second-stage amplified signal.
Description
本公开实施例涉及信号处理技术领域,更具体地,涉及一种信号放大电路和芯片。Embodiments of the present disclosure relate to the technical field of signal processing, and more specifically, to a signal amplification circuit and a chip.
发明背景Background of the invention
由于皮肤电信号很微弱,不经过放大处理很难被识别出来,而人体的各种生命体征和活动都会产生不同的皮肤电信号,通过处理后就可以被很容易识别出来,进而利用这些处理以后得到的数据进行各种应用,对于低频小信号的采集、放大电路可应用于采集生物电信号领域,比如医学领域,可穿戴电子设备领域等。Because the electrodermal signal is very weak, it is difficult to be identified without amplification processing, and various vital signs and activities of the human body will produce different electrodermal signals, which can be easily identified after processing, and then use these processing in the future The obtained data can be used in various applications. For the acquisition and amplification of low-frequency small signals, it can be applied to the field of bioelectric signal collection, such as the medical field and the field of wearable electronic devices.
但是现有的放大电路对于小信号的放大过程中,存在输入偏移高,对于共模电压下的检测信号放大效果不理想的问题。However, in the process of amplifying small signals in the existing amplifying circuit, there is a problem that the input offset is high, and the amplifying effect of the detection signal under the common mode voltage is not ideal.
发明内容Contents of the invention
本公开实施例的一个目的是提供一种信号放大电路和芯片的新的技术方案。An object of the embodiments of the present disclosure is to provide a new technical solution for a signal amplifying circuit and a chip.
根据本公开的第一方面,提供了一种信号放大电路,包括:一级放大电路、二级放大电路和信号转换电路,一级放大电路包括第一信号输入端、第二信号输入端和仪表放大器,第一信号输入端和第二信号输入端分别连接至仪表放大器的第一端和第二端,第一信号输入端和第二信号输入端用于采集检测信号,仪表放大器用于根据检测信号生成一级放大信号;二级放大电路包括运算放大器,运算放大器的第一端用于接收一级放大信号,运算放大器用于根据一级放大信号生成二级放大信号,运算放大器的第二端用于输出二级放大信号;信号转换电路包括模拟数字转换器,模拟数字转换器的第一端用于接收二级放大信号,模拟数字转换器的第一端用于输出基于二级放大信号的数字信号。According to the first aspect of the present disclosure, a signal amplifying circuit is provided, including: a primary amplifying circuit, a secondary amplifying circuit and a signal conversion circuit, the primary amplifying circuit includes a first signal input terminal, a second signal input terminal and an instrument amplifier, the first signal input end and the second signal input end are respectively connected to the first end and the second end of the instrumentation amplifier, the first signal input end and the second signal input end are used for collecting detection signals, and the instrumentation amplifier is used for detecting The signal generates a primary amplified signal; the secondary amplifying circuit includes an operational amplifier, the first end of the operational amplifier is used to receive the primary amplified signal, the operational amplifier is used to generate a secondary amplified signal according to the primary amplified signal, and the second end of the operational amplifier Used to output the secondary amplified signal; the signal conversion circuit includes an analog-to-digital converter, the first end of the analog-to-digital converter is used to receive the secondary amplified signal, and the first end of the analog-to-digital converter is used to output the signal based on the secondary amplified signal Digital signal.
根据本公开的第二方面,还提供了一种芯片,包括:电路板和信号放大电路,信号放大电路设置在电路板上,信号放大电路包括第一方面的信号放大电路;其中,信号放大电路包括依次连接的一级放大电路、二级放大电路和信号转换电路。According to the second aspect of the present disclosure, there is also provided a chip, including: a circuit board and a signal amplifying circuit, the signal amplifying circuit is arranged on the circuit board, and the signal amplifying circuit includes the signal amplifying circuit of the first aspect; wherein, the signal amplifying circuit It includes a primary amplifying circuit, a secondary amplifying circuit and a signal conversion circuit connected in sequence.
本公开实施例的一个有益效果在于,本实施例采用具有仪表放大器的一级放大电路,以及具有运算放大器的二级放大电路,利用仪表放大器的高输入阻抗和高共模抑制比的特性,能够具有更好的信号放大效果。A beneficial effect of the embodiment of the present disclosure is that this embodiment adopts a first-stage amplifying circuit with an instrumentation amplifier and a second-stage amplifying circuit with an operational amplifier, and utilizes the characteristics of high input impedance and high common-mode rejection ratio of the instrumentation amplifier to be able to It has a better signal amplification effect.
通过以下参照附图对本公开的示例性实施例的详细描述,本公开实施例的其它特征及其优点将会变得清楚。Other features and advantages of embodiments of the present disclosure will become apparent through the following detailed description of exemplary embodiments of the present disclosure with reference to the accompanying drawings.
附图简要说明Brief description of the drawings
被结合在说明书中并构成说明书的一部分的附图示出了本公开的实施例,并且连同其说明一起用于解释本公开实施例的原理。The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and, together with the description, serve to explain principles of the embodiments of the disclosure.
图1为本实施例提供一种信号放大电路;Fig. 1 provides a kind of signal amplifying circuit for the present embodiment;
图2是本实施例提供的一级放大电路的电路结构;Fig. 2 is the circuit structure of the primary amplifier circuit provided by the present embodiment;
图3是本实施例提供的一级放大电路的放大倍数与管脚配置的关系图;FIG. 3 is a relationship diagram between the magnification factor and the pin configuration of the primary amplifier circuit provided by this embodiment;
图4是本实施例提供的第一滤波电路的电路图;Fig. 4 is a circuit diagram of the first filtering circuit provided by the present embodiment;
图5是本实施例提供的二级放大电路的电路图;Fig. 5 is the circuit diagram of the secondary amplification circuit provided by the present embodiment;
图6是本实施例提供的二级放大电路的放大倍数关系参考图;FIG. 6 is a reference diagram of the magnification factor relationship of the secondary amplifier circuit provided in this embodiment;
图7是本实施例提供的第二滤波电路和信号转换电路的电路图。FIG. 7 is a circuit diagram of a second filter circuit and a signal conversion circuit provided in this embodiment.
现在将参照附图来详细描述本公开的各种示例性实施例。应注意到:除非另外具体说明,否则在这些实施例中阐述的部件和步骤的相对布置、数字表达式和数值不限制本发明的范围。Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangements of components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.
以下对至少一个示例性实施例的描述实际上仅仅是说明性的,决不作为对本发明及其应用或使用的任何限制。The following description of at least one exemplary embodiment is merely illustrative in nature and in no way taken as limiting the invention, its application or uses.
对于相关领域普通技术人员已知的技术、方法和设备可能不作详细讨论,但在适当情况下,所述技术、方法和设备应当被视为说明书的一部分。Techniques, methods and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such techniques, methods and devices should be considered part of the description.
在这里示出和讨论的所有例子中,任何具体值应被解释为仅仅是示例性的,而不是作为限制。因此,示例性实施例的其它例子可以具有不同的值。In all examples shown and discussed herein, any specific values should be construed as exemplary only, and not as limitations. Therefore, other instances of the exemplary embodiment may have different values.
应注意到:相似的标号和字母在下面的附图中表示类似项,因此,一旦某一项在一个附图中被定义,则在随后的附图中不需要对其进行进一步讨论。It should be noted that like numerals and letters denote like items in the following figures, therefore, once an item is defined in one figure, it does not require further discussion in subsequent figures.
参考图1,本实施例提供一种信号放大电路,包括:一级放大电路101、 二级放大电路102和信号转换电路103,一级放大电路101设置有第一信号输入端J1、第二信号输入端J2,第一信号输入端J1和第二信号输入端J2用于采集检测信号。一级放大电路101用于对接收到的检测信号进行一级放大,二级放大电路102用于对接收到的检测信号进行二级放大,信号转换电路用于根据放大后的二级放大信号进行算法运算,进而识别出皮肤电信号内需要识别的信息。With reference to Fig. 1, the present embodiment provides a kind of signal amplifying circuit, comprises: one-stage amplifying circuit 101, two-stage amplifying circuit 102 and signal conversion circuit 103, one-stage amplifying circuit 101 is provided with first signal input terminal J1, second signal The input terminal J2, the first signal input terminal J1 and the second signal input terminal J2 are used for collecting detection signals. The primary amplification circuit 101 is used for primary amplification of the received detection signal, the secondary amplification circuit 102 is used for secondary amplification of the received detection signal, and the signal conversion circuit is used for performing secondary amplification according to the amplified secondary amplified signal. Algorithm operation, and then identify the information that needs to be identified in the electrodermal signal.
第一信号输入端J1和第二信号输入端J2可以是两个金属电极,通过将第一信号输入端J1和第二信号输入端J2对应的金属电极紧贴皮肤形成回路,以实现皮肤电信号的传递和采集。一级放大电路101接收该检测信号,并对接收到的检测信号进行一级放大后,输出一级放大后的信号至二级放大电路102,二级放大电路102再对一级放大后的信号进行二级放大,并输出至信号转换电路103,信号转换电路103根据二级放大后的信号进行算法运算,进而识别出皮肤电信号内需要识别的信息。The first signal input terminal J1 and the second signal input terminal J2 can be two metal electrodes, and the metal electrodes corresponding to the first signal input terminal J1 and the second signal input terminal J2 are placed close to the skin to form a circuit to realize electrodermal signal delivery and collection. The primary amplification circuit 101 receives the detection signal, and after performing primary amplification on the received detection signal, outputs the signal after the primary amplification to the secondary amplification circuit 102, and the secondary amplification circuit 102 amplifies the signal after the primary amplification. Perform secondary amplification and output to the signal conversion circuit 103. The signal conversion circuit 103 performs algorithmic calculations based on the secondary amplified signal, and then recognizes the information that needs to be recognized in the electrodermal signal.
本实施例中,一级放大电路101包括第一信号输入端J1、第二信号输入端J2和仪表放大器U1A,第一信号输入端J1和第二信号输入端J2分别连接至仪表放大器U1A的第一端和第二端,第一信号输入端J1和第二信号输入端J2用于采集检测信号,仪表放大器U1A用于根据检测信号生成一级放大信号。In this embodiment, the primary amplifying circuit 101 includes a first signal input terminal J1, a second signal input terminal J2 and an instrumentation amplifier U1A, and the first signal input terminal J1 and the second signal input terminal J2 are respectively connected to the first signal input terminal of the instrumentation amplifier U1A. The first terminal and the second terminal, the first signal input terminal J1 and the second signal input terminal J2 are used to collect detection signals, and the instrumentation amplifier U1A is used to generate a first-stage amplified signal according to the detection signals.
本实施例中,二级放大电路102包括运算放大器U1B,运算放大器U1B的第一端用于接收一级放大信号,运算放大器的第二端用于输出二级放大信号,运算放大器U1B用于根据一级放大信号生成二级放大信号。In this embodiment, the secondary amplifying circuit 102 includes an operational amplifier U1B, the first terminal of the operational amplifier U1B is used to receive the primary amplified signal, the second terminal of the operational amplifier is used to output the secondary amplified signal, and the operational amplifier U1B is used to The first-stage amplified signal generates a second-stage amplified signal.
本实施例中,信号转换电路103包括模拟数字转换器ADC,模拟数字转换器ADC的第一端用于接收二级放大信号,模拟数字转换器ADC的第二端用于将接收到的二级放大信号进行模数转换后,输出二级放大信号的数字信号。In this embodiment, the signal conversion circuit 103 includes an analog-to-digital converter ADC, the first end of the analog-to-digital converter ADC is used to receive the secondary amplified signal, and the second end of the analog-to-digital converter ADC is used to convert the received secondary After the amplified signal undergoes analog-to-digital conversion, the digital signal of the secondary amplified signal is output.
本实施例通过连续设置的一级放大电路101和二级放大电路102对检测信号进行两级放大,能够具有更好的信号放大效果。In this embodiment, the detection signal is amplified in two stages through the successively arranged primary amplifier circuit 101 and secondary amplifier circuit 102 , which can have a better signal amplification effect.
需要说明的是,本实施例中的电路是针对小信号电路设计,因此,电路检测信号的频率小于1KHz。It should be noted that the circuit in this embodiment is designed for small signal circuits, therefore, the frequency of the circuit detection signal is less than 1 KHz.
本实施例中,检测信号可以是皮肤表面的低频小信号,该低频小信号可以由皮肤表面的静脉血管或皮肤本身的微电流产生,皮肤表面的电信号幅值在0~5mV范围内,一般为1mV左右。In this embodiment, the detection signal can be a low-frequency small signal on the skin surface, which can be generated by the veins on the skin surface or the micro-current of the skin itself. The amplitude of the electrical signal on the skin surface is in the range of 0-5mV, generally It is about 1mV.
本实施例中,由于仪表放大器具有超高输入阻抗,极其良好的共模抑制比, 低输入偏移,低输出阻抗,因此能放大在共模电压下的信号。In this embodiment, since the instrumentation amplifier has ultra-high input impedance, extremely good common-mode rejection ratio, low input offset, and low output impedance, it can amplify signals under common-mode voltage.
参考图2,本实施例中,一级放大电路101还包括第一差分信号输入端VF1、第二差分信号输入端VF2、参考电压输入端VMID和第一增益调节电路,第一差分信号输入端VF1连接仪表放大器U1A的第一端,第二差分信号输入端VF2连接仪表放大器U1A的第二端,其中,仪表放大器U1A的第一端连接第一信号输入端,仪表放大器U1A的第二端连接第二信号输入端,也就是说,仪表放大器U1A的第一端和第二端为仪表放大器的信号输入端,仪表放大器的第三端为仪表放大器的信号输出端。Referring to Fig. 2, in the present embodiment, the primary amplifying circuit 101 also includes a first differential signal input terminal VF1, a second differential signal input terminal VF2, a reference voltage input terminal VMID and a first gain adjustment circuit, the first differential signal input terminal VF1 is connected to the first terminal of the instrumentation amplifier U1A, and the second differential signal input terminal VF2 is connected to the second terminal of the instrumentation amplifier U1A, wherein, the first terminal of the instrumentation amplifier U1A is connected to the first signal input terminal, and the second terminal of the instrumentation amplifier U1A is connected to The second signal input terminal, that is, the first terminal and the second terminal of the instrumentation amplifier U1A are the signal input terminals of the instrumentation amplifier, and the third terminal of the instrumentation amplifier is the signal output terminal of the instrumentation amplifier.
本实施例中,第一增益调节电路用于配置仪表放大器的增益,第一增益调节电路和参考电压输入端均通过连接管脚连接至仪表放大器,以使仪表放大器根据第一差分信号输入端VF1和第二差分信号输入端VF2输入的差分电压、仪表放大器的增益、参考电压输入端输入的参考电压对检测信号进行放大。In this embodiment, the first gain adjustment circuit is used to configure the gain of the instrumentation amplifier. Both the first gain adjustment circuit and the reference voltage input terminal are connected to the instrumentation amplifier through connecting pins, so that the instrumentation amplifier can The detection signal is amplified by the differential voltage input from the second differential signal input terminal VF2, the gain of the instrumentation amplifier, and the reference voltage input from the reference voltage input terminal.
本实施例中,仪表放大器将差分电压信号VF1和VF2分别与参考电压VMID叠加,并结合增益Q1,得到放大后的单端信号V1,也就是仪表放大器的第三端输出V1,完成第一级放大。In this embodiment, the instrumentation amplifier superimposes the differential voltage signals VF1 and VF2 with the reference voltage VMID respectively, and combines the gain Q1 to obtain the amplified single-ended signal V1, which is the third terminal output V1 of the instrumentation amplifier, and completes the first stage enlarge.
由于第一信号输入端J1和第二信号输入端J2的输入信号为皮肤信号,信号强度较弱,一般为1mV,仪表放大器对输入信号的识别效果较差,因此,采用大于皮肤信号的差分电压信号对皮肤信号进行传输,例如,采用差分电压信号VF1和VF2对皮肤信号进行传输,VF1和VF2的电压值可以为5mV。其中,差分电压信号还可以抵抗除了第一信号输入端J1和第二信号输入端J2的输入信号之外的信号干扰。Since the input signals of the first signal input terminal J1 and the second signal input terminal J2 are skin signals, the signal strength is relatively weak, generally 1mV, and the instrumentation amplifier has a poor recognition effect on the input signal. Therefore, a differential voltage greater than the skin signal is used The signal transmits the skin signal, for example, the skin signal is transmitted by using differential voltage signals VF1 and VF2, and the voltage value of VF1 and VF2 may be 5mV. Wherein, the differential voltage signal can also resist signal interference except the input signals of the first signal input terminal J1 and the second signal input terminal J2.
在一个例子中,仪表放大器的增益为Q1,参考电压VMID可以根据仪表放大器的性能来确定,例如,参考电压VMID为2.5V。由于第一信号输入端J1和第二信号输入端J2的输入信号为模拟信号,因此,利用2.5V的参考电压VMID作为载波,以实现仪表放大器对皮肤信号进行放大,得到放大后的单端信号V1。In an example, the gain of the instrumentation amplifier is Q1, and the reference voltage VMID can be determined according to the performance of the instrumentation amplifier, for example, the reference voltage VMID is 2.5V. Since the input signals of the first signal input terminal J1 and the second signal input terminal J2 are analog signals, the reference voltage VMID of 2.5V is used as the carrier to realize the instrumentation amplifier to amplify the skin signal to obtain an amplified single-ended signal V1.
本实施例中,通过第一增益调节电路对仪表放大器的增益进行调节,第一增益调节电路包括第一增益控制端INA-A0、第二增益控制端INA-A1和第三增益控制端INA-A2,第一增益控制端、第二增益控制端和第三增益控制端通过仪表放大器的不同的连接管脚连接至仪表放大器。例如,图2中仪表放大器的不同的管脚A0、A1、A2分别连接至INA-A0、INA-A1、INA-A2。In this embodiment, the gain of the instrumentation amplifier is adjusted through the first gain adjustment circuit. The first gain adjustment circuit includes a first gain control terminal INA-A0, a second gain control terminal INA-A1 and a third gain control terminal INA- A2, the first gain control terminal, the second gain control terminal and the third gain control terminal are connected to the instrumentation amplifier through different connection pins of the instrumentation amplifier. For example, different pins A0, A1, A2 of the instrumentation amplifier in Fig. 2 are respectively connected to INA-A0, INA-A1, INA-A2.
本实施例中,通过调节第一增益控制端INA-A0、第二增益控制端INA-A1和第三增益控制端INA-A2的电平高低,以调节一级放大电路的放大倍数Q1。其中,第一增益控制端INA-A0、第二增益控制端INA-A1和第三增益控制端INA-A2的电平高低配置与一级放大电路的放大倍数的关系参考图3,由图3可知,当INA-A0、INA-A1和INA-A2的电平均为低电平时,Q1为1;当INA-A0、INA-A1均为低电平,INA-A2为高电平时,Q1为2;当INA-A0为低电平,INA-A1为高电平,INA-A2为低电平时,Q1为4;当INA-A0为低电平,INA-A1为高电平,INA-A2为高电平时,Q1为8;当INA-A0为高电平,INA-A1为低电平,INA-A2为低电平时,Q1为16;当INA-A0为高电平,INA-A1为低电平,INA-A2为高电平时,Q1为32;当INA-A0为高电平,INA-A1为高电平,INA-A2为低电平时,Q1为64;当INA-A0为高电平,INA-A1为高电平,INA-A2为高电平时,Q1为128。In this embodiment, by adjusting the levels of the first gain control terminal INA-A0, the second gain control terminal INA-A1 and the third gain control terminal INA-A2, the amplification factor Q1 of the primary amplifier circuit is adjusted. Among them, the relationship between the level configuration of the first gain control terminal INA-A0, the second gain control terminal INA-A1 and the third gain control terminal INA-A2 and the amplification factor of the first-stage amplifier circuit is referred to FIG. 3 . It can be seen that when the levels of INA-A0, INA-A1 and INA-A2 are all low, Q1 is 1; when INA-A0 and INA-A1 are both low and INA-A2 is high, Q1 is 2; When INA-A0 is low level, INA-A1 is high level, and INA-A2 is low level, Q1 is 4; when INA-A0 is low level, INA-A1 is high level, INA- When A2 is high level, Q1 is 8; when INA-A0 is high level, INA-A1 is low level, and INA-A2 is low level, Q1 is 16; when INA-A0 is high level, INA- When A1 is low level and INA-A2 is high level, Q1 is 32; when INA-A0 is high level, INA-A1 is high level, and INA-A2 is low level, Q1 is 64; when INA- When A0 is high level, INA-A1 is high level, and INA-A2 is high level, Q1 is 128.
本实施例中,一级放大电路101还设置有分压电阻和滤波电容,例如图2中的分压电阻R17,滤波电容C1,分压电阻R17与仪表放大器的片选信号CS端连接,滤波电容C1与仪表放大器的供电VS端连接。In this embodiment, the primary amplifying circuit 101 is also provided with a voltage dividing resistor and a filter capacitor, such as the voltage dividing resistor R17 in FIG. Capacitor C1 is connected to the power supply VS terminal of the instrumentation amplifier.
本实施例中,参考电压输入端用于输入VMID,参考电压输入端连接至仪表放大器的引脚9。In this embodiment, the reference voltage input terminal is used to input VMID, and the reference voltage input terminal is connected to pin 9 of the instrumentation amplifier.
本实施例中,第一差分信号输入端VF1与仪表放大器U1A的第一端之间、第二差分信号输入端VF2与仪表放大器U1A的第二端之间均设置有匹配电阻。匹配电阻的数量可以为2个。例如图2中的电阻R3、R4、R9、R10,其中,R3和R9串联在第一差分信号输入端VF1与仪表放大器U1A的第一端之间,R4和R10串联在第二差分信号输入端VF2与仪表放大器U1A的第二端之间,匹配电阻用于匹配线路阻抗。In this embodiment, matching resistors are provided between the first differential signal input terminal VF1 and the first terminal of the instrumentation amplifier U1A, and between the second differential signal input terminal VF2 and the second terminal of the instrumentation amplifier U1A. The number of matching resistors may be two. For example, resistors R3, R4, R9, and R10 in Figure 2, wherein R3 and R9 are connected in series between the first differential signal input terminal VF1 and the first terminal of the instrumentation amplifier U1A, and R4 and R10 are connected in series between the second differential signal input terminal Between VF2 and the second terminal of the instrumentation amplifier U1A, a matching resistor is used to match the line impedance.
本实施例中,为了滤掉有用带宽以外的杂波信号,电路还包括对一级放大信号进行滤波的第一滤波电路104,第一滤波电路104的第一端与仪表放大器U1A的第三端连接,第一滤波电路104的第二端与运算放大器U1B的第一端连接。In this embodiment, in order to filter out the clutter signals beyond the useful bandwidth, the circuit further includes a first filter circuit 104 for filtering the primary amplified signal, the first terminal of the first filter circuit 104 is connected to the third terminal of the instrumentation amplifier U1A The second end of the first filter circuit 104 is connected to the first end of the operational amplifier U1B.
参考图4,图4为第一滤波电路的电路图,第一滤波电路为带通滤波电路,该电路中的输入为一级放大电路的输出V1,带通滤波电路包括第一滤波电容C3、第四电阻R1、第五电阻R2和第二滤波电容C2,其中,第一滤波电容C3 连接在带通滤波电路的信号输入端,带通滤波电路的信号输入端用于接收一级放大电路的输出信号V1,第二滤波电容C2的第一端与带通滤波电路的参考电压输入端VMID连接,第二滤波电容C2的第二端与带通滤波电路的信号输出端连接,第五电阻R2连接在第一滤波电容C3和第二滤波电容C2之间,第一阻抗R1的一端设置在参考电压端与第二滤波电容C2之间,第四电阻R1的另一端设置在第一滤波电容C3和第五电阻R2之间。经过第一滤波电路对一级放大电路的输出信号V1进行滤波,输出V2。With reference to Fig. 4, Fig. 4 is the circuit diagram of the first filter circuit, the first filter circuit is a band-pass filter circuit, the input in this circuit is the output V1 of the first stage amplifier circuit, the band-pass filter circuit comprises the first filter capacitor C3, the first Four resistors R1, the fifth resistor R2 and the second filter capacitor C2, wherein the first filter capacitor C3 is connected to the signal input end of the band-pass filter circuit, and the signal input end of the band-pass filter circuit is used to receive the output of the primary amplifier circuit Signal V1, the first terminal of the second filter capacitor C2 is connected to the reference voltage input terminal VMID of the band-pass filter circuit, the second terminal of the second filter capacitor C2 is connected to the signal output terminal of the band-pass filter circuit, and the fifth resistor R2 is connected to Between the first filter capacitor C3 and the second filter capacitor C2, one end of the first impedance R1 is set between the reference voltage terminal and the second filter capacitor C2, and the other end of the fourth resistor R1 is set between the first filter capacitor C3 and the second filter capacitor C2. between the fifth resistor R2. The output signal V1 of the primary amplifier circuit is filtered by the first filter circuit to output V2.
本实施例中,参考图5,图5为二级放大电路102的电路图,二级放大电路102包括运算放大器U1B,运算放大器U1B的第一端用于接收过滤后的一级放大信号V2,运算放大器U1B用于根据一级放大信号生成二级放大信号,运算放大器的第二端用于输出二级放大信号V3。In this embodiment, referring to FIG. 5, FIG. 5 is a circuit diagram of the secondary amplifying circuit 102, the secondary amplifying circuit 102 includes an operational amplifier U1B, and the first end of the operational amplifier U1B is used to receive the filtered primary amplified signal V2, and perform the operation The amplifier U1B is used to generate a second-stage amplified signal according to the first-stage amplified signal, and the second terminal of the operational amplifier is used to output the second-stage amplified signal V3.
本实施例中,二级放大电路102还包括第二增益调节电路106,第二增益调节电路106的第一端与运算放大器的第二端连接,第二增益调节电路106的第二端连接运算放大器的第三端。In this embodiment, the secondary amplifier circuit 102 also includes a second gain adjustment circuit 106, the first end of the second gain adjustment circuit 106 is connected to the second end of the operational amplifier, and the second end of the second gain adjustment circuit 106 is connected to the operational amplifier. The third terminal of the amplifier.
参考图5,第二增益调节电路包括第一电阻R7、开关电路U2、第二电阻R5和第三电阻R8,第二电阻R5和第三电阻R8分别连接至开关电路U2的不同支路上的开关件,例如,开关电路U2具有2个不同支路,每一支路上设置有一开关件,则,第二电阻R5连接至开关电路U2的一支路上的开关件,第三电阻R8连接至开关电路U2的另一支路上的开关件。例如图5所示,开关电路U2内设置有第一开关件COM1和第二开关件COM2,第一开关件COM1和第二开关件COM2分别位不同支路上的开关件,第一开关件COM1的第一端和第二开关件COM2的第一端同电位,第一开关件COM1的第二端连接第二电阻R5,所述第二开关件COM2的第二端连接第三电阻R8。Referring to FIG. 5, the second gain adjustment circuit includes a first resistor R7, a switch circuit U2, a second resistor R5 and a third resistor R8, and the second resistor R5 and the third resistor R8 are respectively connected to switches on different branches of the switch circuit U2 For example, the switch circuit U2 has two different branches, each branch is provided with a switch, then the second resistor R5 is connected to the switch on one branch of the switch circuit U2, and the third resistor R8 is connected to the switch circuit A switch on the other branch of U2. For example, as shown in FIG. 5 , the switch circuit U2 is provided with a first switch component COM1 and a second switch component COM2, and the first switch component COM1 and the second switch component COM2 are respectively located on switch components on different branches. The first end is at the same potential as the first end of the second switch COM2, the second end of the first switch COM1 is connected to the second resistor R5, and the second end of the second switch COM2 is connected to the third resistor R8.
本实施例中,第一电阻R7与开关电路U2、第二电阻R5和第三电阻R8形成的电路并联。In this embodiment, the first resistor R7 is connected in parallel with the circuit formed by the switch circuit U2, the second resistor R5 and the third resistor R8.
参考图5,第二增益调节电路还连接有参考电压VMID,用于为第二增益调节电路提供参考电压,其中第二增益调节电路还设置有滤波电容C5,滤波电容C5与第一电阻R7并联。Referring to FIG. 5, the second gain adjustment circuit is also connected with a reference voltage VMID for providing a reference voltage for the second gain adjustment circuit, wherein the second gain adjustment circuit is also provided with a filter capacitor C5, and the filter capacitor C5 is connected in parallel with the first resistor R7 .
本实施例中,带通滤波器输出信号V2输入到运算放大器U1B端,经过二级放大,放大倍数Q2由一级放大倍数Q1,开关电路U2及外围电路决定。In this embodiment, the output signal V2 of the band-pass filter is input to the terminal of the operational amplifier U1B, and after two stages of amplification, the amplification factor Q2 is determined by the primary amplification factor Q1, the switch circuit U2 and peripheral circuits.
本实施例中,开关电路的输入端包括第一增益控制端BIO_LF_GAINS1和第二增益控制端BIO_LF_GAINS2,第一增益控制端和第二增益控制端用于输入高低电平,通过控制第一增益控制端BIO_LF_GAINS1和第二增益控制端BIO_LF_GAINS2的电平来控制第一开关件COM1和第二开关件COM2的开关通断,从而控制接入电路中的总阻值,以调节二级放大电路的放大倍数Q2,得到不同放大倍数的二级放大电路。二级放大电路的放大倍数参考图6,由图6可知,当第一增益控制端BIO_LF_GAINS1和第二增益控制端BIO_LF_GAINS2均为低电平时,二级放大电路的放大倍数Q2等于182Q1;当BIO_LF_GAINS1为高电平,BIO_LF_GAINS2为低电平时,Q2等于76Q1;当BIO_LF_GAINS1为低电平,BIO_LF_GAINS2为高电平时,Q2等于56Q1;当BIO_LF_GAINS1和BIO_LF_GAINS2均为高电平时,Q2等于39Q1。In this embodiment, the input terminal of the switch circuit includes a first gain control terminal BIO_LF_GAINS1 and a second gain control terminal BIO_LF_GAINS2. The first gain control terminal and the second gain control terminal are used to input high and low levels. By controlling the first gain control terminal The level of BIO_LF_GAINS1 and the second gain control terminal BIO_LF_GAINS2 controls the on-off of the first switching element COM1 and the second switching element COM2, thereby controlling the total resistance in the access circuit to adjust the amplification factor Q2 of the secondary amplifier circuit , to obtain two-stage amplifier circuits with different magnifications. Refer to Figure 6 for the amplification factor of the secondary amplifier circuit. It can be seen from Figure 6 that when the first gain control terminal BIO_LF_GAINS1 and the second gain control terminal BIO_LF_GAINS2 are both at low levels, the secondary amplifier circuit’s amplification factor Q2 is equal to 182Q1; when BIO_LF_GAINS1 is High level, when BIO_LF_GAINS2 is low level, Q2 is equal to 76Q1; when BIO_LF_GAINS1 is low level, when BIO_LF_GAINS2 is high level, Q2 is equal to 56Q1; when both BIO_LF_GAINS1 and BIO_LF_GAINS2 are high level, Q2 is equal to 39Q1.
本实施例中,参考图7,电路还包括对二级放大信号进行滤波的第二滤波电路105,第二滤波电路105的第一端与运算放大器的第二端连接,第二滤波电路105的第二端与模拟数字转换器的第一端连接。In this embodiment, with reference to Fig. 7, the circuit also includes a second filter circuit 105 for filtering the secondary amplified signal, the first end of the second filter circuit 105 is connected to the second end of the operational amplifier, and the second end of the second filter circuit 105 The second terminal is connected with the first terminal of the analog-to-digital converter.
在一个可行的例子中,第二滤波电路为由第六电阻R28和第三滤波电容C18组成的低通滤波器,第六电阻的一端连接至运算放大器的信号输出端,第三滤波电容连接至模拟数字转换器的第一端。低通滤波器输入电压为V3,输出电压为V4。In a feasible example, the second filter circuit is a low-pass filter composed of a sixth resistor R28 and a third filter capacitor C18, one end of the sixth resistor is connected to the signal output terminal of the operational amplifier, and the third filter capacitor is connected to The first side of the analog-to-digital converter. The input voltage of the low-pass filter is V3, and the output voltage is V4.
本实施例中,信号转换电路包括模拟数字转换器,模拟数字转换器U5的第一端用于接收二级放大信号,模拟数字转换器的第一端用于输出基于二级放大信号的数字信号。在一个可行的例子中。该数字信号可以经过通信总线接口输入到主控芯片,进行算法运算,进而识别出皮肤电信号类需要识别的信息。In this embodiment, the signal conversion circuit includes an analog-to-digital converter, the first end of the analog-to-digital converter U5 is used to receive the secondary amplified signal, and the first end of the analog-to-digital converter is used to output a digital signal based on the secondary amplified signal . In a working example. The digital signal can be input to the main control chip through the communication bus interface, and the algorithm operation is performed, and then the information that needs to be identified can be identified such as the electrodermal signal.
参考图7,信号转换电路还包括用于为模拟数字转换器提供直流电压和交流电压的电压输入端,其中交流电压输入端ANA连接至模拟数字转换器的交流管脚AVDD,直流电压输入端V1P8连接至模拟数字转换器的直流管脚DVDD,交流电压输入端ANA还连接至模拟数字转换器的驱动端REF。其中,交流电压输入端ANA与模拟数字转换器的驱动端REF之间的驱动电路上设置有驱动电阻R27以及分压电阻R30。交流电压输入端ANA连接有滤波电容C15和C16,直流电压输入端V1P8连接有滤波电容C17。Referring to FIG. 7, the signal conversion circuit further includes a voltage input terminal for providing a DC voltage and an AC voltage to the analog-to-digital converter, wherein the AC voltage input terminal ANA is connected to the AC pin AVDD of the analog-to-digital converter, and the DC voltage input terminal V1P8 It is connected to the DC pin DVDD of the analog-to-digital converter, and the AC voltage input terminal ANA is also connected to the driving terminal REF of the analog-to-digital converter. Wherein, a driving resistor R27 and a voltage dividing resistor R30 are provided on the driving circuit between the AC voltage input terminal ANA and the driving terminal REF of the analog-to-digital converter. The AC voltage input terminal ANA is connected with filter capacitors C15 and C16, and the DC voltage input terminal V1P8 is connected with a filter capacitor C17.
本实施例采用具有仪表放大器的一级放大电路,以及具有运算放大器的二 级放大电路,利用仪表放大器的高输入阻抗和高共模抑制比的特性,能够具有更好的信号放大效果;且一级放大电路和一级放大电路各自的增益都可以调节,使用起来更灵活。This embodiment adopts a primary amplifying circuit with an instrumentation amplifier and a secondary amplifying circuit with an operational amplifier, and utilizes the characteristics of high input impedance and high common-mode rejection ratio of the instrumentation amplifier to have a better signal amplification effect; and a The respective gains of the first-stage amplifier circuit and the first-stage amplifier circuit can be adjusted, making it more flexible to use.
本实施例还提供一种芯片,包括:电路板和信号放大电路,信号放大电路为本实施例提供的信号放大电路,信号放大电路包括依次连接的一级放大电路、二级放大电路和信号转换电路,信号放大电路设置在电路板上。This embodiment also provides a chip, including: a circuit board and a signal amplifying circuit, the signal amplifying circuit is the signal amplifying circuit provided in this embodiment, and the signal amplifying circuit includes a first-stage amplifying circuit, a second-stage amplifying circuit and a signal conversion circuit connected in sequence circuit, and the signal amplifying circuit is arranged on the circuit board.
本实施例利用仪表放大器的高输入阻抗和高共模抑制比的特性,能够具有更好的信号放大效果,并将一级放大电路和二级放大电路封装在一个芯片里,在电路设计上能够更省空间。This embodiment utilizes the characteristics of high input impedance and high common-mode rejection ratio of the instrumentation amplifier to have a better signal amplification effect, and the primary amplifier circuit and the secondary amplifier circuit are packaged in one chip, which can be used in circuit design. Save space.
以上已经描述了本发明的各实施例,上述说明是示例性的,并非穷尽性的,并且也不限于所披露的各实施例。在不偏离所说明的各实施例的范围和精神的情况下,对于本技术领域的普通技术人员来说许多修改和变更都是显而易见的。本文中所用术语的选择,旨在最好地解释各实施例的原理、实际应用或对市场中的技术改进,或者使本技术领域的其它普通技术人员能理解本文披露的各实施例。Having described various embodiments of the present invention, the foregoing description is illustrative, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and alterations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principle of each embodiment, practical application or technical improvement in the market, or to enable other ordinary skilled in the art to understand each embodiment disclosed herein.
Claims (11)
- 一种信号放大电路,其中,包括:一级放大电路、二级放大电路和信号转换电路,A signal amplifying circuit, including: a primary amplifying circuit, a secondary amplifying circuit and a signal conversion circuit,所述一级放大电路包括第一信号输入端、第二信号输入端和仪表放大器,所述第一信号输入端和第二信号输入端分别连接至所述仪表放大器的第一端和第二端,所述第一信号输入端和第二信号输入端用于采集检测信号,所述仪表放大器用于根据所述检测信号生成一级放大信号;The primary amplifying circuit includes a first signal input terminal, a second signal input terminal and an instrumentation amplifier, and the first signal input terminal and the second signal input terminal are respectively connected to the first terminal and the second terminal of the instrumentation amplifier , the first signal input terminal and the second signal input terminal are used to collect a detection signal, and the instrumentation amplifier is used to generate a first-stage amplified signal according to the detection signal;所述二级放大电路包括运算放大器,所述运算放大器的第一端用于接收所述一级放大信号,所述运算放大器用于根据所述一级放大信号生成二级放大信号,所述运算放大器的第二端用于输出所述二级放大信号;The secondary amplifying circuit includes an operational amplifier, the first end of which is used to receive the primary amplified signal, and the operational amplifier is used to generate a secondary amplified signal according to the primary amplified signal. The second end of the amplifier is used to output the secondary amplified signal;所述信号转换电路包括模拟数字转换器,所述模拟数字转换器的第一端用于接收所述二级放大信号,所述模拟数字转换器的第一端用于输出基于所述二级放大信号的数字信号。The signal conversion circuit includes an analog-to-digital converter, the first end of the analog-to-digital converter is used to receive the secondary amplified signal, and the first end of the analog-to-digital converter is used to output Signal digital signal.
- 根据权利要求1所述的信号放大电路,其中,所述一级放大电路还包括第一差分信号输入端、第二差分信号输入端、参考电压输入端和第一增益调节电路,The signal amplifying circuit according to claim 1, wherein the first stage amplifying circuit further comprises a first differential signal input terminal, a second differential signal input terminal, a reference voltage input terminal and a first gain adjustment circuit,所述第一差分信号输入端连接所述仪表放大器的第一端,所述第二差分信号输入端连接所述仪表放大器的第二端,所述第一增益调节电路用于配置所述仪表放大器的增益,所述第一增益调节电路和所述参考电压输入端均通过连接管脚连接至所述仪表放大器,以使所述仪表放大器根据仪表放大器的增益、所述第一差分信号输入端和第二差分信号输入端输入的差分电压、参考电压输入端输入的参考电压对所述检测信号进行放大。The first differential signal input terminal is connected to the first terminal of the instrumentation amplifier, the second differential signal input terminal is connected to the second terminal of the instrumentation amplifier, and the first gain adjustment circuit is used to configure the instrumentation amplifier The gain of the first gain adjustment circuit and the reference voltage input terminal are both connected to the instrumentation amplifier through connecting pins, so that the instrumentation amplifier can use the gain of the instrumentation amplifier, the first differential signal input terminal and The differential voltage input from the second differential signal input terminal and the reference voltage input from the reference voltage input terminal amplify the detection signal.
- 根据权利要求2所述的信号放大电路,其中,所述第一增益调节电路包括第一增益控制端、第二增益控制端和第三增益控制端,所述第一增益控制端、第二增益控制端和第三增益控制端通过不同的连接管脚连接至所述仪表放大器,通过调节所述第一增益控制端、第二增益控制端和第三增益控制端的电平高低,以调节所述一级放大电路的放大倍数。The signal amplifying circuit according to claim 2, wherein the first gain adjustment circuit comprises a first gain control terminal, a second gain control terminal and a third gain control terminal, the first gain control terminal, the second gain The control terminal and the third gain control terminal are connected to the instrumentation amplifier through different connection pins, and the levels of the first gain control terminal, the second gain control terminal and the third gain control terminal are adjusted to adjust the The magnification of the primary amplifier circuit.
- 根据权利要求1所述的信号放大电路,其中,所述二级放大电路还包括第二增益调节电路,The signal amplifying circuit according to claim 1, wherein the secondary amplifying circuit further comprises a second gain adjusting circuit,所述第二增益调节电路的第一端与所述运算放大器的第二端连接,所述第二增益调节电路的第二端连接所述运算放大器的第三端。The first end of the second gain adjustment circuit is connected to the second end of the operational amplifier, and the second end of the second gain adjustment circuit is connected to the third end of the operational amplifier.
- 根据权利要求4所述的信号放大电路,其中,The signal amplifying circuit according to claim 4, wherein,所述第二增益调节电路包括第一电阻、开关电路、第二电阻和第三电阻,所述第二电阻和第三电阻分别连接至所述开关电路的不同支路上的开关件,所述第一电阻与所述开关电路、第二电阻和第三电阻形成的电路并联。The second gain adjustment circuit includes a first resistor, a switch circuit, a second resistor and a third resistor, the second resistor and the third resistor are respectively connected to switching elements on different branches of the switch circuit, the first A resistor is connected in parallel with the circuit formed by the switch circuit, the second resistor and the third resistor.
- 根据权利要求5所述的信号放大电路,其中,所述开关电路的输入端包括第一增益控制端和第二增益控制端,所述第一增益控制端和所述第二增益控制端用于输入高电平或低电平,以调节所述开关电路的开关件的关断和导通,得到不同放大倍数的二级放大电路。The signal amplifying circuit according to claim 5, wherein the input terminal of the switch circuit includes a first gain control terminal and a second gain control terminal, and the first gain control terminal and the second gain control terminal are used for Input a high level or a low level to adjust the switching off and on of the switch element of the switching circuit to obtain a secondary amplification circuit with different amplification factors.
- 根据权利要求1所述的信号放大电路,其中,所述电路还包括对所述一级放大信号进行滤波的第一滤波电路,The signal amplifying circuit according to claim 1, wherein the circuit further comprises a first filtering circuit for filtering the first-stage amplified signal,所述第一滤波电路的第一端与所述仪表放大器的第三端连接,所述第一滤波电路的第二端与所述运算放大器的第一端连接,其中,所述仪表放大器的第三端为所述仪表放大器的信号输出端。The first end of the first filter circuit is connected to the third end of the instrumentation amplifier, the second end of the first filter circuit is connected to the first end of the operational amplifier, wherein the first end of the instrumentation amplifier The three terminals are signal output terminals of the instrumentation amplifier.
- 根据权利要求1所述的信号放大电路,其中,所述第一滤波电路为带通滤波电路,具体包括:第一滤波电容、第四电阻、第五电阻和第二滤波电容,The signal amplifying circuit according to claim 1, wherein the first filter circuit is a band-pass filter circuit, specifically comprising: a first filter capacitor, a fourth resistor, a fifth resistor, and a second filter capacitor,所述第一滤波电容连接在所述带通滤波电路的信号输入端,第二滤波电容的第一端与所述带通滤波电路的参考电压输入端连接,所述第二滤波电容的第二端与所述带通滤波电路的信号输出端连接,所述第五电阻连接在第一滤波电容和第二滤波电容之间,所述第五电阻的一端设置在所述参考电压端与第二滤波电容之间,所述第四电阻的另一端设置在所述第一滤波电容和所述第五电阻之间。The first filter capacitor is connected to the signal input end of the band-pass filter circuit, the first end of the second filter capacitor is connected to the reference voltage input end of the band-pass filter circuit, and the second filter capacitor of the second terminal is connected to the signal output terminal of the bandpass filter circuit, the fifth resistor is connected between the first filter capacitor and the second filter capacitor, and one end of the fifth resistor is set between the reference voltage terminal and the second filter capacitor. Between the filter capacitors, the other end of the fourth resistor is arranged between the first filter capacitor and the fifth resistor.
- 根据权利要求1所述的信号放大电路,其中,所述电路还包括对所述二级放大信号进行滤波的第二滤波电路,The signal amplifying circuit according to claim 1, wherein the circuit further comprises a second filter circuit for filtering the secondary amplified signal,所述第二滤波电路的第一端与所述运算放大器的第二端连接,所述第二滤波电路的第二端与所述模拟数字转换器的第一端连接。The first terminal of the second filter circuit is connected to the second terminal of the operational amplifier, and the second terminal of the second filter circuit is connected to the first terminal of the analog-to-digital converter.
- 根据权利要求1所述的信号放大电路,其中,第二滤波电路为低通滤波电路,具体包括:第六电阻和第三滤波电容,The signal amplifying circuit according to claim 1, wherein the second filter circuit is a low-pass filter circuit, specifically comprising: a sixth resistor and a third filter capacitor,所述第六电阻的一端连接至所述运算放大器的信号输出端,所述第三滤波电容连接至所述模拟数字转换器的第一端。One end of the sixth resistor is connected to the signal output end of the operational amplifier, and the third filter capacitor is connected to the first end of the analog-to-digital converter.
- 一种芯片,其中,包括:电路板和信号放大电路,A chip, including: a circuit board and a signal amplification circuit,所述信号放大电路设置在所述电路板上,所述信号放大电路包括权利要求1-10中任一项所述的信号放大电路;The signal amplifying circuit is arranged on the circuit board, and the signal amplifying circuit comprises the signal amplifying circuit according to any one of claims 1-10;其中,所述信号放大电路包括依次连接的一级放大电路、二级放大电路和信号转换电路。Wherein, the signal amplifying circuit includes a primary amplifying circuit, a secondary amplifying circuit and a signal converting circuit connected in sequence.
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