TW201326830A - Bio-potential sensing circuit and method - Google Patents
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本發明係關於生物電訊號感測電路及方法，特別是關於可適應不同電極類型的生物電訊號感測電路及方法。The present invention relates to a bioelectric signal sensing circuit and method, and more particularly to a bioelectric signal sensing circuit and method that can accommodate different electrode types.
隨著醫療科技發展的日新月異，對於醫療用品需求量與品質要求大增，使得醫療保健的生醫感測用品在未來具有相當之成長空間。目前常用之生理訊號量測與使用的電極形態包括：濕式電極，例如醫院的心電圖與肌電圖之量測使用，以濕的凝膠或食鹽水與皮膚接觸，其電極阻抗值最低(約為100Ω~5kΩ)，其訊號量測方法以差動式放大電路加上右腳反饋(Driven Right Leg,DRL)作雜訊消除；乾式電極，例如不銹鋼電極或氯化銀電極，與皮膚做直接接觸，因其阻抗值較高(約為1kΩ~20kΩ)，以差動式放大電路作為量測電路；電容式電極，具有非接觸感測之特性，常使用軟式塑膠電極或織物電極與金屬薄片，在絕緣隔離下與皮膚做近距離接觸感測(無實質電性接觸)，因其電極為絕緣隔離所以阻抗值很高(約為100Ω~100MΩ、10pF~100nF)，其訊號量測方法主要以電容中和電路加上後端差動式放大電路為主。先前技術中，低阻抗電極(濕式電極)的感測電路無法套用高阻抗電極(乾式電極、電容式電極)，高阻抗電極(乾式電極、電容式電極)亦無法套用低阻抗電極(濕式電極)的感測電路。再者，於實際應用中，電極的阻抗值常因測量環境的變化改變。例如以乾式電極量測一運動員之心律，一開始運動員的皮膚乾燥，電極的阻抗較高，但當運動員開始流汗後，會使得電極端的等效阻抗降低。因此，勢必需要一種可以適應各種類電極與各種量測環境的生物電訊號感測電路。With the rapid development of medical technology, the demand for medical products and the demand for quality have increased greatly, which makes the medical and health sensing products of medical care have considerable room for growth in the future. Currently used physiological signal measurement and electrode forms used include: wet electrodes, such as hospital electrocardiogram and electromyography measurement, with wet gel or saline contact with the skin, the electrode impedance is the lowest (about 100Ω~5kΩ), the signal measurement method uses differential amplifier circuit plus Driven Right Leg (DRL) for noise cancellation; dry electrode, such as stainless steel electrode or silver chloride electrode, directly with the skin Contact, because of its high impedance value (about 1kΩ~20kΩ), with differential amplifier circuit as measurement circuit; capacitive electrode with non-contact sensing characteristics, often using soft plastic electrode or fabric electrode and foil In close contact with the skin under insulation isolation (no substantial electrical contact), because the electrodes are insulated and isolated, the impedance is very high (about 100Ω~100MΩ, 10pF~100nF), and the signal measurement method is mainly The capacitor neutralization circuit plus the back-end differential amplifier circuit is mainly used. In the prior art, the sensing circuit of the low-impedance electrode (wet electrode) cannot apply the high-impedance electrode (dry electrode, capacitive electrode), and the high-impedance electrode (dry electrode, capacitive electrode) cannot apply the low-impedance electrode (wet type) Sensing circuit of the electrode). Furthermore, in practical applications, the impedance value of the electrode often changes due to changes in the measurement environment. For example, an athlete's heart rhythm is measured by a dry electrode. At first, the athlete's skin is dry and the impedance of the electrode is high, but when the athlete starts to sweat, the equivalent impedance of the electrode end is lowered. Therefore, there is a need for a bioelectric signal sensing circuit that can accommodate various types of electrodes and various measurement environments.
有鑑於此，本發明提出一種生物電訊號感測電路，包括一第一電極，接收一第一生物訊號；該第一生物訊號包括一第一生理特徵以及一第一雜訊；一第一電容，一端與一第一電極電性連接；一第一控制單元，一端與該第一電容之另一端電性連接，另一端電性連接至一參考電位節點；一第二電極，接收一第二生物訊號；該第二生物訊號包括一第二生理特徵以及一第二雜訊；一第二電容，一端與一第二電極電性連接；一第二控制單元，一端與該第二電容之另一端電性連接，另一端電性連接至該參考電位節點；一輸入平衡單元，分別與該第一電容之該另一端以及該第二電容之該另一端耦合，並根據該第一生物訊號以及該第二生物訊號，產生一第一控制訊號及/或一第二控制訊號，分別控制該第一控制單元及/或該第二控制單元，以使該第一雜訊及該第二雜訊之振幅相等；一差動放大器，輸入端分別與該第一電容之該另一端以及該第二電容之該另一端耦合，以接收該第一生物訊號以及該第二生物訊號並產生一輸出訊號。In view of the above, the present invention provides a bioelectric signal sensing circuit including a first electrode for receiving a first biosignal; the first biosignal includes a first physiological characteristic and a first noise; and a first capacitor One end is electrically connected to a first electrode; a first control unit has one end electrically connected to the other end of the first capacitor, the other end is electrically connected to a reference potential node; and a second electrode receives a second The second biological signal includes a second physiological characteristic and a second noise; a second capacitor is electrically connected at one end to a second electrode; and a second control unit is coupled to the second capacitor One end is electrically connected, and the other end is electrically connected to the reference potential node; an input balancing unit is respectively coupled to the other end of the first capacitor and the other end of the second capacitor, and according to the first biological signal and The second biosignal generates a first control signal and/or a second control signal to respectively control the first control unit and/or the second control unit to make the first noise and the second miscellaneous The amplitudes are equal; a differential amplifier is coupled to the other end of the first capacitor and the other end of the second capacitor to receive the first biosignal and the second biosignal and generate an output signal .
本發明另提出一種量測生物電訊號的方法，包括分別量測一第一生物訊號以及一第二生物訊號，其中該第一生物訊號以及該第二生物訊號分別包括一第一雜訊以及一第二雜訊；判別該第一雜訊以及該第二雜訊的振幅是否相等；若第一雜訊之振幅大於第二雜訊之振幅時，縮小該第一雜訊之振幅或放大該第二雜訊之振幅；若第一電極雜訊之振幅小於第二電極雜訊之振幅時，放大該第一雜訊之振幅或縮小該第二雜訊之振幅；重複以上步驟直至該第一電極以及該第二電極的雜訊振幅相等；以及差動放大接收自該第一電極以及該第二電極的生理訊號。The present invention further provides a method for measuring a bioelectric signal, comprising separately measuring a first biosignal and a second biosignal, wherein the first biosignal and the second biosignal respectively comprise a first noise and a first Second noise; determining whether the amplitude of the first noise and the second noise are equal; if the amplitude of the first noise is greater than the amplitude of the second noise, reducing the amplitude of the first noise or amplifying the first The amplitude of the second noise; if the amplitude of the first electrode noise is smaller than the amplitude of the second electrode noise, amplifying the amplitude of the first noise or reducing the amplitude of the second noise; repeating the above steps until the first electrode And the noise amplitude of the second electrode is equal; and differentially amplifying the physiological signals received from the first electrode and the second electrode.
第1圖為本發明之一實施例中，生物電訊號感測電路100的結構示意圖。首先參見第1圖，生物電訊號感測電路100包括第一電極P1以及第二電極P2。部分實施例中，第一電極P1以及第二電極P2可以是乾式電極，濕式電極，或是電容式電極，但不僅限於此。第一電極P1以及第二電極P2可以為相同類型的電極或是不同類型的電極。FIG. 1 is a schematic structural view of a bioelectric signal sensing circuit 100 according to an embodiment of the present invention. Referring first to FIG. 1, the bioelectric signal sensing circuit 100 includes a first electrode P1 and a second electrode P2. In some embodiments, the first electrode P1 and the second electrode P2 may be dry electrodes, wet electrodes, or capacitive electrodes, but are not limited thereto. The first electrode P1 and the second electrode P2 may be the same type of electrodes or different types of electrodes.
第一電極P1以及第二電極P2與欲測量的生物體或生物組織接觸，以分別取得第一生物電訊號S1以及第二生物電訊號S2，如第2A及2B圖所示。第一生物電訊號S1以及第二生物電訊號S2為生物的肌肉組織、神經系統、器官或細胞所產生的電壓資訊。於部分實施例中，第一生物電訊號S1以及第二生物電訊號S2可以是腦電波(EEG)、皮膚電位反應(GSR)、心電訊號(ECG)、肌電訊號(EMG)，或是心律變化(HRV)等，但不僅限於此。第一生物電訊號S1以及第二生物電訊號S2分別包括第一及第二生物電位V1、V2，第一及第二雜訊Q1、Q2，以及第一及第二生理特徵R1、R2。第一及第二生物電位V1、V2以及第一及第二雜訊Q1、Q2係為生物本身的環境電位及背景雜訊，第一及第二生理特徵R1、R2則為生物的肌肉組織、神經系統、器官或細胞所產生的電壓變化。The first electrode P1 and the second electrode P2 are in contact with the living organism or biological tissue to be measured to obtain the first bioelectric signal S1 and the second bioelectric signal S2, respectively, as shown in FIGS. 2A and 2B. The first bioelectric signal S1 and the second bioelectric signal S2 are voltage information generated by the muscle tissue, nervous system, organ or cell of the living being. In some embodiments, the first bioelectric signal S1 and the second bioelectric signal S2 may be an electroencephalogram (EEG), a skin potential response (GSR), an electrocardiogram (ECG), an electromyography (EMG), or Heart rate changes (HRV), etc., but are not limited to this. The first bioelectric signal S1 and the second bioelectric signal S2 respectively include first and second biopotentials V1, V2, first and second noises Q1, Q2, and first and second physiological features R1, R2. The first and second biopotentials V1, V2 and the first and second noises Q1, Q2 are the environmental potential and background noise of the organism itself, and the first and second physiological features R1, R2 are the muscle tissue of the living being, Changes in voltage produced by the nervous system, organs or cells.
接著參見第1圖，生物電訊號感測電路100包括第一電容C1以及第二電容C2，一端分別耦接於第一電極P1以及第二電極P2，以接收第一生物電訊號S1以及第二生物電訊號S2。第一電容C1以及第二電容C2一般具有較高之電容值(例如大於1μF)，用於耦合前端生理訊號及使直流部分的生物電位V1及V2被過濾，而第一及第二生理特徵R1、R2與第一及第二雜訊Q1、Q2得以通過。第一電容C1以及第二電容C2之另一端分別輸出第一生物電訊號S1’以及第二生物電訊號S2’，其中第一生物電訊號S1’與電極所接收的第一生物電訊號S1差別僅在於直流部分的生物電位V1已被消除；第二生物電訊號S2’與電極所接收的第二生物電訊號S2差別僅在於直流部分的生物電位V2已被消除。Referring to FIG. 1 , the bioelectric signal sensing circuit 100 includes a first capacitor C1 and a second capacitor C2. One end is coupled to the first electrode P1 and the second electrode P2 to receive the first bioelectric signal S1 and the second. Bioelectric signal S2. The first capacitor C1 and the second capacitor C2 generally have a higher capacitance value (for example, greater than 1 μF) for coupling the front end physiological signals and filtering the biopotentials V1 and V2 of the direct current portion, and the first and second physiological characteristics R1 And R2 and the first and second noises Q1 and Q2 are passed. The other ends of the first capacitor C1 and the second capacitor C2 respectively output the first bioelectric signal S1' and the second bioelectric signal S2', wherein the first bioelectric signal S1' is different from the first bioelectric signal S1 received by the electrode. Only the biopotential V1 of the DC portion has been eliminated; the second bioelectric signal S2' differs from the second bioelectric signal S2 received by the electrode only in that the biopotential V2 of the DC portion has been eliminated.
如第1圖所示，生物電訊號感測電路100更包括第一控制單元M1以及第二控制單元M2，電壓隨耦器AMP1及AMP2。第一控制單元M1以及第二控制單元M2之一端分別與第一電容C1以及第二電容C2之另一端電性耦接，另一端則電性耦接至一參考電位節點GND；電壓隨耦器AMP1及AMP2之輸入端分別耦接於第一電容C1以及第二電容C2之另一端，作為微弱輸入訊號之阻抗轉換，以將第一生物電訊號S1’以及第二生物電訊號S2’傳遞至電壓隨耦器AMP1及AMP2之輸出端。電壓隨耦器AMP1及AMP2之輸出端更分別連接至節點n1及n2。於部分實施例中，第一電容C1以及第二電容C2之另一端更與一具有阻抗匹配及靜電放電保護功能之電路(包括二極體D1及D2)電性連接，將靜電放電產生的額外電壓導入參考電位節點GND，避免生物電訊號感測電路100受損。於部分實施例中，當第一電極P1或第二電極P2為電容型電極時，更分別具有一外環L1及L2(以虛線標示於第1圖)，分別電性連接至節點n1及n2，以與感測電極之電位保持著很低的電壓差，這樣能讓微小訊號容易脫離既有之電容電壓差的門檻進入電壓隨耦器AMP1及AMP2。於部分實施例中，電壓隨耦器AMP1及AMP2的回饋線路更包括串聯如電阻、電容等被動元件，為求圖式簡明，並未繪示於第1圖。As shown in FIG. 1, the bioelectric signal sensing circuit 100 further includes a first control unit M1 and a second control unit M2, voltage followers AMP1 and AMP2. One end of the first control unit M1 and the second control unit M2 are electrically coupled to the other ends of the first capacitor C1 and the second capacitor C2, respectively, and the other end is electrically coupled to a reference potential node GND; the voltage follower The input terminals of the AMP1 and the AMP2 are respectively coupled to the other ends of the first capacitor C1 and the second capacitor C2, and are used as impedance conversion of the weak input signal to transmit the first bioelectric signal S1' and the second bioelectric signal S2' to The output of the voltage follower AMP1 and AMP2. The outputs of the voltage followers AMP1 and AMP2 are connected to nodes n1 and n2, respectively. In some embodiments, the other ends of the first capacitor C1 and the second capacitor C2 are electrically connected to a circuit having impedance matching and electrostatic discharge protection functions (including the diodes D1 and D2) to add an extra electrostatic discharge. The voltage is introduced into the reference potential node GND to prevent damage to the bioelectric signal sensing circuit 100. In some embodiments, when the first electrode P1 or the second electrode P2 is a capacitive electrode, there are respectively an outer ring L1 and L2 (shown in FIG. 1 by dashed lines), which are electrically connected to the nodes n1 and n2, respectively. To maintain a very low voltage difference with the potential of the sensing electrode, this allows the tiny signal to easily escape from the threshold of the existing capacitor voltage into the voltage followers AMP1 and AMP2. In some embodiments, the feedback circuits of the voltage followers AMP1 and AMP2 further include passive components such as resistors and capacitors in series, which are not shown in FIG. 1 for the sake of simplicity.
生物電訊號感測電路100更包括輸入平衡單元10，具有輸入端a1及a2，分別連接至節點n1’與n2’。節點n1’與n2’更分別與節點n1及n2電性耦接，以接收來自電壓隨耦器AMP1及AMP2之輸出端的第一生物電訊號S1’以及第二生物電訊號S2’。於部分實施例中，節點n1與n1’，以及節點n2與n2’之間更存在有電阻、電容等被動元件或主動式濾波器等主動元件。為求圖式簡明，該些被動元件並未繪示於第1圖；平衡單元10更包括輸出端f1及f2，分別與第一控制單元M1以及第二控制單元M2耦接。輸入平衡單元10自輸入端a1及a2讀取第一生物電訊號S1’以及第二生物電訊號S2’加以分析，並根據分析結果從輸出端f1及f2輸出第一控制電壓以及/或第二控制電壓，以分別調整第一控制單元M1及/或第二控制單元M2的電阻值，使第一生物電訊號S1以及第二生物電訊號S2的雜訊振幅得以平衡。於一較佳實施例中，輸入平衡單元10於待測生物組織未產生第一及第二生理特徵R1、R2時(例如肌肉放鬆未產生肌電訊號時)，輸入端a1及a2所讀取的第一生物電訊號S1’以及第二生物電訊號S2’即為第一雜訊Q1及第二雜訊Q2。於部分實施例中，輸入平衡單元10更透過一反饋電路DRL及一第三電極P3，將平衡後之第一雜訊Q1及第二雜訊Q2以相反相位右腳反饋(Driven Right Leg)至人體，以消除雜訊之影響。The bioelectric signal sensing circuit 100 further includes an input balancing unit 10 having input terminals a1 and a2 connected to nodes n1' and n2', respectively. The nodes n1' and n2' are electrically coupled to the nodes n1 and n2, respectively, to receive the first bioelectric signal S1' and the second bioelectric signal S2' from the outputs of the voltage followers AMP1 and AMP2. In some embodiments, between the nodes n1 and n1', and between the nodes n2 and n2', there are active elements such as passive components such as resistors and capacitors or active filters. For the sake of simplicity, the passive components are not shown in FIG. 1; the balancing unit 10 further includes output terminals f1 and f2 coupled to the first control unit M1 and the second control unit M2, respectively. The input balancing unit 10 reads the first bioelectric signal S1' and the second bioelectric signal S2' from the input terminals a1 and a2 for analysis, and outputs the first control voltage and/or the second from the output terminals f1 and f2 according to the analysis result. The voltage is controlled to adjust the resistance values of the first control unit M1 and/or the second control unit M2, respectively, so that the noise amplitudes of the first bioelectric signal S1 and the second bioelectric signal S2 are balanced. In a preferred embodiment, the input balancing unit 10 reads the first and second physiological features R1 and R2 when the biological tissue to be tested does not generate (for example, muscle relaxation does not produce myoelectric signals), and the input terminals a1 and a2 read The first bioelectric signal S1' and the second bioelectric signal S2' are the first noise Q1 and the second noise Q2. In some embodiments, the input balancing unit 10 further transmits the balanced first noise Q1 and the second noise Q2 to the opposite phase by the feedback circuit DRL and the third electrode P3. The human body to eliminate the effects of noise.
如第1圖所示，於本實施例中，第一控制單元M1以及第二控制單元M2為場效電晶體(FET)，分別具有第一閘極以及第二閘極。因此下文中亦將第一控制單元M1以及第二控制單元M2稱為第一電晶體M1及第二電晶體M2；輸入平衡單元10的輸出端f1及f2分別電性耦合至第一電晶體M1以及第二電晶體M2的第一閘極以及第二閘極，並輸出第一控制電壓及/或第二控制電壓，以控制第一閘極及/或第二閘極，調整第一控制單元M1及/或第二控制單元M2的電阻值。於其他部分實施例中，第一控制單元M1以及第二控制單元M2可以是任何種類的電壓控制阻抗可變元件，根據輸出端f1及f2的輸出電訊號，調整第一控制單元M1及/或第二控制單元M2的電阻值。As shown in FIG. 1, in the embodiment, the first control unit M1 and the second control unit M2 are field effect transistors (FETs) having a first gate and a second gate, respectively. Therefore, the first control unit M1 and the second control unit M2 are hereinafter referred to as a first transistor M1 and a second transistor M2; the output terminals f1 and f2 of the input balancing unit 10 are electrically coupled to the first transistor M1, respectively. And the first gate and the second gate of the second transistor M2, and outputting the first control voltage and/or the second control voltage to control the first gate and/or the second gate to adjust the first control unit The resistance value of M1 and/or the second control unit M2. In other embodiments, the first control unit M1 and the second control unit M2 may be any type of voltage-controlled impedance variable element, and the first control unit M1 is adjusted according to the output signals of the output terminals f1 and f2. The resistance value of the second control unit M2.
生物電訊號感測電路100更包括一差動放大器DIF，其輸入端分別與輸入端a1及a2、第一電容C1以及第二電容C2之另一端電性耦合，將雜訊振幅平衡後的第一生物電訊號S1’以及第二生物電訊號S2’做差動處理後產生一輸出訊號，自輸出端OUT輸出。The bioelectric signal sensing circuit 100 further includes a differential amplifier DIF, and the input ends thereof are electrically coupled to the other ends of the input terminals a1 and a2, the first capacitor C1 and the second capacitor C2, respectively, and the noise amplitude is balanced. A bioelectric signal S1' and a second bioelectric signal S2' are differentially processed to generate an output signal, which is output from the output terminal OUT.
第3圖則揭露第1圖之實施例中，輸入平衡單元10之生物電訊號平衡方法流程圖。首先於步驟12，輸入平衡單元10的輸入端a1及a2分別接收來自第一及第二電極P1及P2的第一及第二雜訊Q1、Q2。接著進行步驟14，輸入平衡單元10判別第一及第二雜訊Q1、Q2的振幅w1及w2(顯示於第2圖)是否相同，若相同，則直接進入步驟16，完成平衡；若不相同，則進行步驟18，比較振幅w1及w2的大小。Figure 3 is a flow chart showing the bioelectric signal balancing method of the input balancing unit 10 in the embodiment of Fig. 1. First, in step 12, the input terminals a1 and a2 of the input balancing unit 10 receive the first and second noises Q1 and Q2 from the first and second electrodes P1 and P2, respectively. Next, in step 14, the input balancing unit 10 determines whether the amplitudes w1 and w2 (shown in FIG. 2) of the first and second noises Q1 and Q2 are the same. If they are the same, the process proceeds directly to step 16 to complete the balance; Then, proceed to step 18 to compare the magnitudes of the amplitudes w1 and w2.
若振幅w1小於振幅w2，則進行步驟20，輸入平衡單元10提高輸出端f2的第二控制電壓，使第二電晶體M2的閘極較為開啟，減少第二電晶體M2的電阻值。此時第一電容C2之另一端之第一生理特徵R2與第一雜訊Q2會一同縮小；輸入平衡單元10亦可降低輸出端f1的第一控制電壓，使第一電晶體M1的閘極較為關閉，增加第一電晶體M1的電阻值。此時第一電容C1之另一端之第一生理特徵R1與第一雜訊Q1會一同放大。於部分實施例中，輸入平衡單元10可同時提高輸出端f2的第二控制電壓並降低輸出端f1的第一控制電壓，以縮小第一生理特徵R2與第一雜訊Q2並同時放大第一生理特徵R1與第一雜訊Q1。接著重複執行步驟12，直至第一及第二雜訊Q1、Q2的振幅w1及w2相同，完成兩者的雜訊振幅平衡。If the amplitude w1 is smaller than the amplitude w2, the step 20 is performed, and the input balancing unit 10 increases the second control voltage of the output terminal f2 to open the gate of the second transistor M2, thereby reducing the resistance value of the second transistor M2. At this time, the first physiological characteristic R2 of the other end of the first capacitor C2 is reduced together with the first noise Q2; the input balancing unit 10 can also lower the first control voltage of the output terminal f1 to make the gate of the first transistor M1 Closed, increasing the resistance of the first transistor M1. At this time, the first physiological characteristic R1 of the other end of the first capacitor C1 is amplified together with the first noise Q1. In some embodiments, the input balancing unit 10 can simultaneously increase the second control voltage of the output terminal f2 and reduce the first control voltage of the output terminal f1 to reduce the first physiological characteristic R2 and the first noise Q2 and simultaneously amplify the first Physiological feature R1 and first noise Q1. Then, step 12 is repeated until the amplitudes w1 and w2 of the first and second noises Q1 and Q2 are the same, and the noise amplitude balance between the two is completed.
若振幅w1大於振幅w2，則進行步驟22，輸入平衡單元10降低輸出端f2的第二控制電壓，使第二電晶體M2的閘極較為關閉，提高第二電晶體M2的電阻值。此時第二電容C2之另一端之第二生理特徵R2與第二雜訊Q2會一同放大；輸入平衡單元10亦可提高輸出端f1的第一控制電壓，使第一電晶體M1的閘極較為開啟，降低第一電晶體M1的電阻值。此時第一電容C1之另一端之第一生理特徵R1與第一雜訊Q1會一同縮小。於部分實施例中，輸入平衡單元10可同時降低輸出端f2的第二控制電壓並提高輸出端f1的第一控制電壓，以放大第二生理特徵R2與第二雜訊Q2並同時縮小第一生理特徵R1與第一雜訊Q1。接著重複執行步驟12，直至第一及第二雜訊Q1、Q2的振幅w1及w2相同，完成兩者的雜訊振幅平衡。If the amplitude w1 is greater than the amplitude w2, the step 22 is performed, and the input balancing unit 10 lowers the second control voltage of the output terminal f2 to close the gate of the second transistor M2, thereby increasing the resistance value of the second transistor M2. At this time, the second physiological characteristic R2 of the other end of the second capacitor C2 is amplified together with the second noise Q2; the input balancing unit 10 can also increase the first control voltage of the output terminal f1 to make the gate of the first transistor M1 It is turned on to lower the resistance value of the first transistor M1. At this time, the first physiological characteristic R1 of the other end of the first capacitor C1 is reduced together with the first noise Q1. In some embodiments, the input balancing unit 10 can simultaneously reduce the second control voltage of the output terminal f2 and increase the first control voltage of the output terminal f1 to amplify the second physiological characteristic R2 and the second noise Q2 and simultaneously reduce the first Physiological feature R1 and first noise Q1. Then, step 12 is repeated until the amplitudes w1 and w2 of the first and second noises Q1 and Q2 are the same, and the noise amplitude balance between the two is completed.
本發明提供之生物電訊號感測電路，可以適應各種類電極，包括乾式電極，濕式電極，以及電容式電極；並可以接受量測環境的變化對電極阻抗所造成的影響，增加感測電路的適用範圍及時機，提高其與不同量測需求的整合度及泛用性。The bioelectric signal sensing circuit provided by the invention can adapt to various types of electrodes, including dry electrodes, wet electrodes, and capacitive electrodes; and can accept the influence of changes in the measurement environment on the impedance of the electrodes, and increase the sensing circuit. The scope of application is timely and the integration and versatility of different measurement requirements are improved.
10．．．輸入平衡單元10. . . Input balance unit
100．．．生物電訊號感測電路100. . . Bioelectric signal sensing circuit
12、14、16、18、20、22．．．步驟12, 14, 16, 18, 20, 22. . . step
a1．．．第一輸入端A1. . . First input
a2．．．第二輸入端A2. . . Second input
AMP1、AMP2．．．電壓隨耦器AMP1, AMP2. . . Voltage follower
C1．．．第一電容C1. . . First capacitor
C2．．．第二電容C2. . . Second capacitor
D1．．．二極體D1. . . Dipole
D2．．．二極體D2. . . Dipole
DRL．．．右腳反饋電路DRL. . . Right foot feedback circuit
f1、f2．．．輸出端F1, f2. . . Output
GND．．．參考電位節點GND. . . Reference potential node
L1、L2．．．外環L1, L2. . . Outer ring
M1．．．第一控制單元M1. . . First control unit
M2．．．第二控制單元M2. . . Second control unit
n1、n1’、n2、n2’．．．節點N1, n1', n2, n2'. . . node
OUT．．．輸出端OUT. . . Output
P1-P3．．．電極P1-P3. . . electrode
Q1、Q2．．．第一及第二雜訊Q1, Q2. . . First and second noise
R1、R2．．．第一及第二生理特徵R1, R2. . . First and second physiological characteristics
S1、S1’．．．第一生物電訊號S1, S1’. . . First bioelectric signal
S2、S2’．．．第二生物電訊號S2, S2’. . . Second bioelectric signal
w1、w2．．．第一及第二雜訊振福W1, w2. . . First and second noises
V1、V2．．．第一及第二生理電位V1, V2. . . First and second physiological potentials
第1圖為本發明之一實施例中，生物電訊號感測電路100的結構示意圖；1 is a schematic structural diagram of a bioelectric signal sensing circuit 100 according to an embodiment of the present invention;
第2a圖為本發明之一實施例中，生物電訊號S1之波形示意圖；2a is a schematic diagram showing the waveform of the bioelectric signal S1 in an embodiment of the present invention;
第2b圖為本發明之一實施例中，生物電訊號S2之波形示意圖；2b is a schematic diagram showing the waveform of the bioelectric signal S2 in an embodiment of the present invention;
第3圖為本發明第1圖之實施例中輸入平衡單元10之平衡方法流程圖。Figure 3 is a flow chart showing the method of balancing the input balancing unit 10 in the embodiment of Figure 1 of the present invention.
10．．．輸入平衡單元10. . . Input balance unit
100．．．生物電訊號感測電路100. . . Bioelectric signal sensing circuit
a1．．．第一輸入端A1. . . First input
a2．．．第二輸入端A2. . . Second input
AMP1、AMP2．．．電壓隨耦器AMP1, AMP2. . . Voltage follower
C1．．．第一電容C1. . . First capacitor
C2．．．第二電容C2. . . Second capacitor
D1．．．二極體D1. . . Dipole
D2．．．二極體D2. . . Dipole
DRL．．．右腳反饋電路DRL. . . Right foot feedback circuit
f1、f2．．．輸出端F1, f2. . . Output
GND．．．參考電位節點GND. . . Reference potential node
L1、L2．．．外環L1, L2. . . Outer ring
M1．．．第一控制單元M1. . . First control unit
M2．．．第二控制單元M2. . . Second control unit
n1、n1’、n2、n2’．．．節點N1, n1', n2, n2'. . . node
OUT．．．輸出端OUT. . . Output
P1-P3．．．電極P1-P3. . . electrode
S1、S1’．．．第一生物電訊號S1, S1’. . . First bioelectric signal
S2、S2’．．．第二生物電訊號S2, S2’. . . Second bioelectric signal
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