1226522 A7 B7 五、發明説明（1) 【技術領域】 本發明是關於，電位固定裝置、電位固定方法及電容 測定裝置，特別是關於，用以固定第1電容與第2電容間 的連接線的電位的電位固定裝置、電位固定方法及包含這 種電位固定裝置的電容測定裝置。 【技術背景】 傳統上有一種習用的電容測定裝置，用以測定電容式 麥克風等，各種頻率會使其靜電容量改變的電容。第6圖 是表示以往的電容測定裝置的一個例子的電路圖。如第6 圖所示，以往的電容測定裝置具備有：運算放大器1 1 2、交 流電壓產生器1 1 3、被測定電容1 1 4、及當作回授阻抗的回 授電阻1 1 6。回授電阻1 1 6與被測定電容1 1 4是經由信號線 117連接在一起。在運算放大器112的一方端子連接有信號 線1 1 7。而與被測定電容1 1 4的連接在信號線1 1 7的一側相 反的一側的電極，連接有交流電壓產生器1 1 3的一方端子 。而交流電壓產生器1 1 3的另一方端子則接地。 在此，被測定電容1 14所具有的靜電電容C s，會因接 受到的物理量（加速度、壓力、氣體、光、音波等）而變化。 而交流電壓產生器1 1 3是用以產生，在測定容量時施加在 被測定電容1 1 4的動作信號V in。 第6圖所示的傳統電容測定裝置的電容測定動作是， 當從交流電壓產生器1 13產生動作信號（電壓：V in)時，該 動作信號的電壓V in加在被測定電容1 1 4的兩端。藉此， 本紙張尺度適用中國國家標準（CNS ) Α4規格（21〇Χ297公釐） (請先閱讀背面之注意事項再填寫本頁) -J— I J1 ·1226522 A7 B7 V. Description of the invention (1) [Technical field] The present invention relates to a potential fixing device, a potential fixing method, and a capacitance measuring device, and more particularly, to fixing a connection line between a first capacitor and a second capacitor. Potential fixing device, potential fixing method, and capacitance measuring device including the potential fixing device. [Technical Background] Conventionally, there is a conventional capacitance measuring device for measuring the capacitance of a condenser microphone, etc., at various frequencies whose capacitance will change. Fig. 6 is a circuit diagram showing an example of a conventional capacitance measuring device. As shown in Fig. 6, a conventional capacitance measuring device includes an operational amplifier 1 1 2, an AC voltage generator 1 1 3, a measured capacitance 1 1 4 and a feedback resistance 1 1 6 as a feedback impedance. The feedback resistance 1 1 6 and the measured capacitance 1 1 4 are connected via a signal line 117. A signal line 1 1 7 is connected to one terminal of the operational amplifier 112. On the other side of the electrode connected to the capacitor 1 1 4 to be measured on the opposite side to the signal line 1 1 7, one terminal of the AC voltage generator 1 1 3 is connected. The other terminal of the AC voltage generator 1 1 3 is grounded. Here, the capacitance C s included in the measured capacitance 114 varies depending on the physical quantity (acceleration, pressure, gas, light, sound wave, etc.) received. The AC voltage generator 1 1 3 is used to generate an operation signal V in which is applied to the measured capacitance 1 1 4 when measuring the capacity. The capacitance measurement operation of the conventional capacitance measurement device shown in FIG. 6 is that when an operation signal (voltage: V in) is generated from the AC voltage generator 1 13, the voltage V in of the operation signal is added to the capacitance to be measured 1 1 4 Both ends. As a result, this paper size applies the Chinese National Standard (CNS) Α4 specification (21〇 × 297 mm) (Please read the precautions on the back before filling this page) -J— I J1 ·
、1T 經濟部智慧財產局員工消費合作社印製 -4- 1226522 A7 ___B7 ' 五、發明説明（2) (請先閲讀背面之注意事項再填寫本頁) 在被測定電容114有電流流通。這時，運算放大器H2的 輸入阻抗在理想狀態時是無限大，因此，流通於被測定電 容1 1 4的電流將全部流過回授電阻1丨6。藉此，可以從信號 輸出端子1 1 8輸出，對應被測定電容1 1 4的靜電電容C s的 輸出電壓V out。而依據此檢測信號的輸出電壓v out進行 各種信號處理，便可以獲得靜電電容Cs。 第6圖所示的傳統的電容測定裝置，其回授阻抗使用 回授電阻1 1 6，因 此，信號輸出端子1 1 8的輸出電壓V out會具有，如下 式（1)所示的頻率特性。 V out = -Rf((Cd + AC · sin ω c t) · 6； in · cos 6； in t + AC · ω c · cos ω c t · sino in t〕V i ............(1) 篸照上式（1 )，Vi是從交流電壓產生器1 1 3送出的信號 V in的振幅，in是 經濟部智慧財產局員工消費合作社印製 動作信號V i η的角速度。而C d是被測定電容1 14的 標準電容値，AC及ω c分別是被測定電容1 1 4中，電容變 化分的電容値及角速度。在上述式（1)，電容變化分的角速 度ω c含有與電容變化分的電容値AC成比例的項目。因此 ，輸出電壓V out與電容變化分的頻率（ω c/2 π = f c)成比 例，因而具有頻率特性。因此，必須在後級重行配設處理 電路，使其不具頻率特性。其結果，會使電路規模變大。 因而有人建議回授阻抗不用電阻，而改以電容器構成 本紙張尺度適用中國國家標準（CNS ) A4規格（210X297公釐） -5- 1226522 Α7 Β7 經濟部智慧財產局員工消費合作社印製 五、發明説明（3) 的技術。第7圖便是表示這種電容測定裝置的電路圖。參 照第7圖，此電容測定裝置的回授阻抗以回授電容1 1 5構 成。此電路的輸出電壓V out以下式（2)表示。 V out =〔（ C d + AC · sin ω c t) /C f〕V in ............(2) 如上述式（2)所示，以回授電容11 5(電容値：C f)構成 回授阻抗，靜電電容Cs所儲存的電荷與回授電容115的電 容値C f所儲存的電荷會相等，因此可以使信號線1 1 7的電 荷量保持一定値。藉此，輸出電壓V out不含與角速度ω c 成比例的項目。因此，電路輸出沒有對電容變化頻率的依 存性，不必在後級爲使其不據頻率特性，而重行配設的處 理電路。其結果，可以防止電路規模變大。 然而，如第7圖所示的技術，以回授電容1 15構成回 授阻抗時，位於回授電容1 1 5與被測定電容1 1 4間的信號 線1 1 7不會有直流電流流通，信號線1 1 7成爲浮動狀態。 因此，信號線1 1 7的電位變不穩定，電路輸出對電源電壓 成飽和狀態等，電路會無法正常動作。 爲了防止上述不妥，也可以如第7圖所示，在信號線 1 1 7與GND的間連接電阻1 1 9，藉此固定信號線1 1 7的電 位。 然而，如上述，若藉由電阻1 1 9固定電位，在測定電 容時，有時會在電阻119流通電流。這時，信號線117的 電荷量會發生變化，因而有電容測定裝置的靈敏度降低的 (請先閲讀背面之注意事項再填寫本頁) -J— I J— · 『裝· 訂 本紙張尺度適用中國國家標準（CNS ) A4規格（210X297公釐） -6- 1226522 A7 B7_ 五、發明説明（4) 問題點。因此，很難正確進行電容測定。 (請先閲讀背面之注意事項再填寫本頁) 而在被測定電容1 14施加V in時’縱使以遮蔽線（未圖 示）被覆信號線1 1 7，同時，藉由假想短路使該遮蔽線與信 號線1 1 7成爲同電位，再將遮蔽線與信號線1 1 7接至GND ，在現實的運算放大器1 1 2，信號線1 1 7不會變成Gnd， 稍有信號V in會存在於信號線1 1 7上。因此，在遮蔽線與 信號線1 1 7間生成雜散電容，而因爲此雜散電容的影響， 使得很難正確進行電容測定。 本發明是爲了解決上述課題而完成者，本發明的一個 目的在提供，能夠防止第1電容與第2電容間的連接線的 電荷量發生變化的電位固定裝置。 本發明的另一目的在提供，固定第1電容與第2電容 間的連接線的電位時，仍不會降低靈敏度，能夠進行正確 的電容測定的電容測定裝置。 本發明的再一目的在提供，能夠防止第1電容與第2 電容間的連接線的電荷量變化的電位固定方法。 經濟部智慧財產局員工消費合作社印製 【發明的揭示】 本發明的一個局面的電位固定裝置，是用以固定第j 電容，與直接連接在該第J電容的第2電容的兩個電容間 的連接線的電位的電位固定裝置，備有，至少有兩個高阻 抗’並能夠保持第1電容與第2電容的合計總電荷量，同 時’將兩個電谷間的連接線的電位維持在一定値的電壓供 應手段。而該電壓供應手段的輸出端子是連接在兩個電容 本紙張尺度適用中國國家標準（CNS ) A4規格（210X297公釐） ' - 1226522 A7 B7 五、發明説明（5) (請先閲讀背面之注意事項再填寫本頁) 間的連接線。再者，本發明的高阻抗除了高電阻外，也可 以使用二極體的逆偏壓特性，或電晶體的截斷狀態，藉此 加以實現。 在上述一個局面的電位固定裝置，可以藉由配設，能 夠保持第1電容與第2電容的合計總電荷量，並將兩個電 容間的連接線的電位維持在一定値的電壓供應手段，同時 ，將該電壓供應手段的輸出端子連接在兩個電容間的連接 線，藉此防止第1電容與第2電容間的連接線的電荷量發 生變化。並且，在電壓供應手段至少含兩個高阻抗，藉此 高阻抗，可以有效防止流通於兩個電容間的連接線的電流 的一部分流進電壓供應手段。如此也可以防止第1電容與 第2電容間的連接線的電荷量發生變化。如此，由於可以 防止第1電容與第2電容間的連接線的電荷量發生變化， 因此，例如在電容測定裝置，固定第1電容與第2電容間 的連接線的電位時，電容測定裝置的靈敏度也不會降低。 其結果，可以進行正確的電容測定。 經濟部智慧財產局員工消費合作社印製 本發明的其他局面的電位固定裝置，是用以固定第1 電容，與直接連接在第1電容的第2電容的兩個電容間的 連接線的電位的電位固定裝置，備有，至少有兩個高阻抗 ，同時，輸出與施加在連接線的動作信號的電位相等電位 的電壓供應手段。而該電壓供應手段的輸出端子是連接在 兩個電容間的連接線。 上述其他局面的電位固定裝置，因爲配設有可以輸出 與施加在第1電容與第2電容的連接線的動作信號的電位 本紙張尺度適用中國國家標準（CNS ) A4規格（210X297公釐） -8- 1226522 A7 B7 五、發明説明（6) (請先閲讀背面之注意事項再填寫本頁) 相等電位的電壓供應手段，同時，將該電壓供應手段的輸 出端子連接在第1電容與第2電容間的連接線，因此，在 第1電容與第2電容的連接線不會有電流出入，可以防止 連接線的合計總電荷量發生變化。並且，在電壓供應手段 至少含有兩個高阻抗，藉此高阻抗可以有效防止流通於連 接線的電流的一部分流進電壓供應手段側。藉此也可以防 止連接線的合計總電荷量發生變化。如此，由於可以能防 止第1電容與第2電容間的連接線的電荷量發生變化，因 此，例如在電容測定裝置，固定第1電容與第2電容間的 連接線的電位時，電容測定裝置的靈敏度也不會降低。其 結果，可以進行正確的電容測定。 經濟部智慧財產局員工消費合作社印製 在上述一個局面或其他局面的電位固定裝置，最好是 ，在電壓供應手段包含：第1高電阻；直接連接在第1高 電阻的第2高電阻；輸出由第1高電阻與第2高電阻分壓 的電位的電壓分壓手段。再者，本發明的「高電阻」，在 對象電容是lpF程度，數百MHz以上時是數ΜΩ以上，對 象電容是1 pF程度，數百KHz〜1 MHz程度時是數百ΜΩ 以上。亦即，「高電阻」表示，具有較之第1電容與第2 電容的阻抗成分充分大的相對高的電阻値的電阻。如此， 將電壓供應手段構成爲包含可輸出由第1高電阻與第2高 電阻分壓的電位的電壓分壓手段，即可藉由適宜選擇第1 高電阻及第2高電阻的電阻値，很容易調節電壓供應手段 的輸出電位。 在上述一個局面或其他局面的電位固定裝置，最好是 本紙張尺度適用中國國家標準（CNS ) A4規格（210 X297公釐） ' -9 - 1226522 A7 _________ B7 _ _ . 五、發明説明（7) (請先閲讀背面之注意事項再填寫本頁) ’在電壓供應手段包含··放大器、規定電壓施加手段、第i 高電阻、第2高電阻、及輸出端子，放大器連接有第丨高 電阻的一方端子，第1高電阻的另一方端子與第2高電阻 的一方端子連接在一起，第1高電阻的另一方端子與第2 高電阻的一方端子之間，連接有輸出端子，第2高電組的 另一方端子與規定電壓施加手段連接在一起。如此構成時 ’決定放大器的放大度、第1高電阻與第2高電阻的電阻 値、規定電壓施加手段的電壓値，便可很容易將電壓供應 手段的輸出端子的電位控制成，與施加在第1電容與第2 電容的連接線的動作信號的電位相等的電位。 本發明的再一其他局面的包含電位固定裝置的電容測 定裝置，電位固定裝置進一步含有第1運算放大器，第1 電容是被測定電容，兩個電容間的連接線是信號線，第1 運算放大器的輸入端子連接在該信號線。 經濟部智慧財產局員工消費合作社印製 上述再一其他局面的電容測定裝置，是構成爲包含具 有上述任一架構的電位固定裝置，同時，使該電位固定裝 置的第1電容爲被測定電容，同時使兩個電容間的連接線 爲信號線，藉此使信號線沒有電流的出入，因而可以防止 連接線的合計總電荷量發生變化。藉此，在電容測定裝置 ，固定第1電容與第2電容間的連接線的電荷時，電容測 定裝置的靈敏度也不會降低。其結果，可以進行正確的電 容測定。 在上述再一其他局面的包含電位固定裝置的電容測定 裝置，最好是，電位固定裝置進一步含有第2運算放大器 本紙張尺度適用中國國家標準（CNS)A4規格（210x297公釐) ~" 1226522 A7 _ B7_ * 五、發明説明（8) ，該第2運算放大器的輸出端子連接在第2電容。如此構 成時，可以將第2運算放大器當作電流源使用。 (請先閱讀背面之注意事項再填寫本頁) 本發明的另一局面的電位固定方法，是用以固定第1 電容，與直接連接在第1電容的第2電容的兩個電容間的 連接線的電位的電位固定方法，以使用至少兩個高電阻分 壓的電位作爲輸出電位，將輸出電位施加在兩個電容間的 連接線，且將該輸出電位固定在連接線沒有電流出入之輸 出電位。 經濟部智慧財產局員工消費合作社印製 上述另一局面的電位固定方法在固定兩個電容間的連 接線的電位時，將施加在兩個電容間的連接線的電位，固 定在該連接線沒有電流出入的輸出電位，藉此可以防止第1 電容與第2電容間的連接線的合計總電荷量發生變化。同 時是以至少兩個尚阻抗分壓的輸出電位固定電壓，藉此尚 阻抗可以有效防止流通於連接線的電流的一部分流進電壓 供應手段側。藉此也可以防止第1電容與第2電容的連接 線的合計總電荷量發生變化。如此，由於可以能防止第1 電容與第2電容間的連接線的電荷量發生變化，因此，例 如在電容測定裝置，固定第1電容與第2電容間的連接線 的電位時，電容測定裝置的靈敏度也不會降低。其結果， 可以進行正確的電容測定。 本發明的另一其他局面的電位固定方法，是用以固定 第1電容，與直接連接在第1電容的第2電容的兩個電容 間的連接線的電位的電位固定方法，以使用至少兩個高電 阻分壓的電位作爲輸出電位，將輸出電位施加在兩個電容 本紙張尺度適用中國國家標準（CNS ) A4規格（210X297公釐） -11 - 1226522 A7 B7 五、發明説明（9) 間的連接線，且將該輸出電位設定在施加於兩個電容間的 連接線的動作電壓的電位相等。 (請先閲讀背面之注意事項再填寫本頁) 在上述另一其他局面的電位固定方法在固定第1電容 與第2電容間的連接線的電位時，將施加於該連接線的輸 出電位設定成與施加在兩個電容間的連接線的動作信號的 電位相等，藉此可以防止兩個電容間的連接線的合計總電 荷量發生變化。並且，藉由使用至少兩個高阻抗分壓的輸 出電位固定電位，因此可以藉由該高阻抗有效防止流通於 連接線的電流的一部分流進高阻抗側。藉此也可以防止連 接線的合計總電荷量發生變化。如此，因爲可以防止兩個 電容間的連接線的電荷量發生變化，因此，例如在電容測 定裝置，固定第1電容與第2電容間的連接線的電位時， 電容測定裝置的靈敏度也不會降低。其結果，可以進行正 確的電容測定。 上述另一局面或另一其他局面的電位固定方法，最好 是，將第1電容與第2電容中的任一方當作被測定電容使 用。如此構成時，便可以很容易進行電容測定。 經濟部智慧財產局員工消費合作社印製 【實施發明的最佳形態】 茲參照附圖說明本發明的實施形態如下。 (第1實施形態） 第1圖是表示本發明第1實施形態的包含電位固定裝 置的電容測定裝置的電路圖，第2圖是表示第1圖所示第1 實施形態的電位固定裝置所含放大器的內部架構的一個例 本紙張尺度適用中國國家標準（CNS〉A4規格（210X297公釐） -12- 1226522 A7 _____B7 _ 五、發明説明（1C) 子的電路圖。 首先，參照第1圖及第2圖，說明第1實施形態的包 含電位固定裝置的電容測定裝置的架構。此第1實施形態 的電容測定裝置備有：運算放大電路12、交流電壓產生器 13、靜電電容Cs、被測定電容14、具有電容値C f的當作 回授阻抗用的固定電容15。再者，運算放大電路12是本發 明的「第1運算放大器」的一個例子。而，被測定電容14 是本發明的「第1電容」或「第2電容」的一個例子，固 定電容15是本發明的「第1電容」或「第2電容」的一個 例子。 被測定電容14與固定電容15以信號線17連接在一起 。信號線17連接在運算放大電路12的一方端子。再者， 此ig 5虎線1 7是本發明的「連接線」的一*個例子。而，跟被 測定電容1 4的連接在信號線17的一側相反的電極，連接 有交流電壓產生器1 3的一方端子。而，跟固定電容15的 連接在信號線17的一側相反的電極，連接在信號輸出端子 1 8。同時，交流電壓產生器1 3的另一端在本實施形態是接 地，但也可以連接在DC成分。再者，被測定電容14是依 接受到的物理量（加速度、壓力、氣體、光、音波等）而改變 其所具有的靜電電容Cs。而，交流電壓產生器13是用以產 生，測定電容時施加在被測定電容1 4的動作信號v in。 在此，第1實施形態的電容測定裝置，是使用備有電 壓供應電路1的電位固定裝置固定信號線1 7的電位。再者 ，電壓供應電路1是本發明的「電壓供應手段」的一個例 1紙張尺度適用中國國家標準（〇灿）八4規格（210、/297公釐） ' -13- (請先閲讀背面之注意事項再填寫本頁) 訂 經濟部智慧財產局員工消費合作社印製 1226522 A7 ___B7 五、發明説明（11) (請先閲讀背面之注意事項再填寫本頁) 子。電壓供應電路1含有：具有放大度A的放大器2;具 有電阻値Ral的第1高電阻3 ;具有電阻値Ra2的第2高 電阻4。第1高電阻3的Ral及第2高電阻4的Ra2均具 有1 ΜΩ以上的電阻値。再者，此電阻値是由使用的頻率及 檢出電容所求得，只要是具有較其特性阻抗相對高很多的 値即可。 而在放大器2的輸入側連接有，跟交流電壓產生器i 3 不同的別的交流電壓產生器（別的電源）7。放大器2的輸出 側，則連接在第1高電阻3的一方端子。第1高電阻3的 另一方端子與第2局電阻4的一方端子之間，連接有輸出 端子5。其電壓供應電路1的輸出端子5在點p，連接於信 5虎線1 7。弟2局電阻4的另一'端設有端子6。此端子6施 加有規定的電位V s。此端子6是本發明的「規定電壓施加 手段」的一個例子。同時，從輸出端子5輸出，由第1高 電阻3與第2高電阻4的電阻分割所分壓的電壓v a。 經濟部智慧財產局員工消費合作社印製 同時，放大器2是具有例如第2圖所示的架構。亦即 ，放大器2含有：運算放大電路21;具有電阻値R1的電 阻22;具有電阻値R2的電阻23。運算放大電路21的非反 轉輸入端子連接有交流電壓產生器7(參照第1圖）。而運算 放大電路21的輸出端子與反轉輸入端子的間連接有電阻22 。同時，運算放大電路21的輸出端子與反轉輸入端子間連 接有電阻22。同時，運算放大電路21的反轉輸入端子與 GND的間連接有電阻23。如此構成，便可很容易獲得放大 度 A = (R 1 + R 2)/ R 2的放大器2。 本紙張尺度適用中國國家標準（CNS〉A4規格（210X297公釐） -14 - 1226522 A7 B7 五、發明説明（ (請先閲讀背面之注意事項再填寫本頁) 第1實施形態的電容測定裝置的電位固定方法是，決 定放大器2的放大度a '第1高電阻3的電阻値Ra 1、第2 高電阻4的電阻値Ra2及端子6的電壓Vs，使流通信號線 1 7的動作信號的電壓V in，與電壓供應電路1的輸出端子 5的電壓Va相等。再者，放大器2的放大度A可以藉由適 宜選擇第2圖所示的電阻22及23的電阻値R 1及R 2，很 容易調節。 第1圖所示的第1實施形態的電容測定裝置的電容測 定動作是，從交流電壓產生器13產生動作信號（電壓·· V in )後，該動作信號的電壓V in加在被測定電容1 4的兩端。 藉此，在被測定電容14有電流流通。這時，運算放大電路 1 2的輸入阻抗在理想狀態時是無限大，因此，流通於被測 定電容1 4的電流將全部流過固定電容1 5。藉此，從信號輸 出端子1 8輸出對應被測定電容1 4的靜電電容C s的輸出電 壓V out。而，依據此檢測信號的輸出電壓V out進行各種 信號處理，便可以獲得被測定電容1 4的靜電電容C s。 經濟部智慧財產局員工消費合作社印製 第1實施形態是如上述，配設有，可在連接被測定電 容1 4與固定電容1 5的信號線1 7施加電位固定用的交流電 壓的電壓供應電路1，同時，將該電壓供應電路1的輸出端 子5的電位設定成，與施加在信號線1 7的動作信號的電位 V in相等，藉此使信號線1 7沒有電流出入，因此可以防止 信號線1 7的電荷量發生變化。 並且，由於在電壓供應手段1包含高阻抗的第1高電 阻3及第2高電阻4，藉此高阻抗可以有效防止流通於連接 本紙張尺度適用中國國家標準（CNS ) A4規格（210X297公釐） -15- 1226522 A7 __________ B7 五、發明説明（ 線1 7的電流的一部分流進電壓洪應手段1側。藉此也可以 防止連接線1 7的電荷量發生變化。 (請先閱讀背面之注意事項再填寫本頁) 第1實施形態是如上述，對信號線1 7不會注入或流出 電荷，因此可以防止信號線1 7的合計總電荷量發生變化。 在此說明，被測定電容1 4與固定電容1 5的合計總電 荷量。如第1圖所示，從交流電壓產生器1 3送出的動作信 號（電壓：V i η)維持一定大小，因此，加在被測定電容J 4 的電壓V s也是一定大小。但是，被測定電容1 4是電容檢 測部，因此，被測定電容14的電容値C s會變化。被測定 電容14的電容値C s的變化，成爲被測定電容14的電荷 量Q s的變化。第1實施形態是如上述，對信號線17沒有 注入或流出電荷，因此，儲存在固定電容15的電荷量Q f ，與儲存在被測定電容1 4的電荷量Q s的和是一定。因此 ，被測定電容1 4的電荷量Q s的增減，顯現成爲固定電容 1 5的電荷量Q f的減增。 經濟部智慧財產局員工消費合作社印製 固定電容1 5的電荷量Q f的變化（減增）因固定電容1 5 的電容値C f 一定，因此，顯現成爲固定電容1 5的電壓値 V f的變化（減增）。而，加在該固定電容15的電壓V f的 輸出，則從信號輸出端子1 8成爲V out而輸出。 亦即，在第1實施形態的電容測定裝置，在被測定電 容14的電容値C s與固定電容15的電容値C f之間有電荷 的送受，但如上述，對信號線1 7沒有注入或流出電荷，因 此，被測定電容14與固定電容15的合計總電荷量是一定 。藉此可以，一面將被測定電容1 4與固定電容1 5的合計 本紙張尺度適用中國國家標準（CNS ) A4規格（210X297公釐） -16- 1226522 A7 B7 五、發明説明（ (請先閲讀背面之注意事項再填寫本頁) 總電荷量保持一定，同時以電壓供應電路1對信號線1 7供 給固定的電位。因此，固定連接被測定電容1 4與固定電容 1 5的信號線1 7的電位時，電容測定裝置的靈敏度也不會降 低。其結果，可以進行正確的電容測定。 (第2實施形態） 第3圖是表示本發明第2實施形態的包含電位固定裝 置的電容測定裝置的電路圖。參照第3圖，本第2實施形 態的電壓供應電路1是，在上述第1實施形態的架構，於 放大器2的輸入側連接可對信號線1 7施加動作信號v in的 交流電壓產生器1 3以取代交流電壓產生器7時的例子。再 者，第2實施形態的其他架構與上述第1實施形態相同。 第2實施形態是如上述，在放大器2的輸入側連接用 以對信號線1 7施加動作信號V in的交流電壓產生器1 3， 藉此可能省略第1實施形態的交流電壓產生器7，可以較第 1實施形態簡化電路架構。 經濟部智慧財產局員工消費合作社印製 同時，第2實施形態是跟上述第1實施形態同樣，藉 由調節放大器2的放大度A、第1高電阻3的電阻値Ral、 第2高電阻4的電阻値Ra2及端子6的電壓Vs，可以很容 易將電壓供應電路1的輸出端子5的電壓V a設定成，與 信號線17的動作信號的電壓V in相等。具體上是，使第2 圖所示的放大器2的電阻22及23的電阻値成爲R1 = R2， 藉此使放大器2的放大度A成爲A = 2，使Vs = 〇V、Ral =Ra2，便可以很容易使電壓供應電路1的輸出端子5的電 本紙張尺度適用中國國家標準（CNS ) A4規格（210X297公釐） -17- 1226522 A 7 _ B7_ 五、發明説明（β 壓Va成爲Va = Vin。 如此，由於將電壓供應電路1的輸出端子5的電壓V a 設定成，與信號線1 7的動作信號的電壓V in相等，因此與 上述第1實施形態同樣，信號線1 7沒有電流的出入，可以 有效防止信號線1 7的電荷量發生變化。其結果，在電容測 定裝置固定連信號線1 7的電位時，電容測定裝置的靈敏度 也不會降低，可以進行正確的電容測定。 (第3實施形態） 第4圖是表示本發明第3實施形態的包含電位固定裝 置的電容測定裝置的電路圖。 首先，參照第4圖，說明第3實施形態的包含電位固 定裝置的電容測定裝置的架構。本第3實施形態備有：成 爲電流源的運算放大電路1 1、在假想短路狀態的運算放大 電路1 2、交流電壓產生器1 3、被測定電容1 4、固定電容 15。再者，運算放大電路11是本發明的「第2運算放大電 路」的一個例子。被測定電容14與固定電容1 5由信號線 1 7連接在一起。信號線1 7連接在運算放大電路1 2的一方 的輸入端子。而，交流電壓產生器13是連接在運算放大電 路1 2的另一方的輸入端子。 在此，第3實施形態是使用備有電壓供應電路1的電 位固定裝置，固定信號線1 7的電位。再者，電壓供應電路 1的架構及所含的放大器2的架構與上述第1實施形態相同 。亦即，電壓供應電路1含有：具有放大度A的放大器2 本紙張尺度適用中國國家標準（CNS ) A4規格（210X297公釐） (請先閱讀背面之注意事項再填寫本頁) 衣· 訂 經濟部智慧財產局員工消費合作社印製 -18- 1226522 A7 B7 五、發明説明（10 (請先閲讀背面之注意事項再填寫本頁) 、第1高電阻3、第2高電阻4。在放大器2的輸入側連接 有跟交流電壓產生器1 3不同的別的交流電壓產生器7。放 大器2的輸出側，則連接有第1高電阻3的一方端子。第1 高電阻3的另一方端子，設有電壓供應電路1的輸出端子5 。該電壓供應電路1的輸出端子5連接於信號線17。第2 高電阻4的另一端設有端子6。此端子6施加有規定的電位 Vs。同時，從輸出端子5輸出，由第1高電阻3與第2高 電阻4的電阻分割而分壓的電壓V a。 第3實施形態的電容測定裝置的電位固定方法是，決 定放大器2的放大度A、第1高電阻3的電阻値Ra 1、第2 高電阻4的電阻値Ra2及端子6的電壓Vs，使流通於信號 線1 7的動作信號的電壓V in，與電壓供應電路1的輸出端 子5的電壓V a相等。 經濟部智慧財產局員工消費合作社印製 第4圖所示的第3實施形態的電容測定裝置的電容測 定動作是，由於運算放大電路12是在假想短路的狀態，從 交流電壓產生器13產生的電壓V in(動作信號）便加在信號 線1 7。藉此，在被測定電容14的兩端有電流流通。而從信 號輸出端子1 8輸出對應被測定電容14的靜電電容C s的 輸出電壓V out。對此輸出電壓V out施以各種信號處理， 便可以獲得被測定電容1 4的靜電電容C s。 第3實施形態是如上述，配設有用以在連接被測定電 容14與固定電容1 5的連接線1 7施加固定電位用的交流電 壓的電壓供應電路1，同時，將該電壓供應電路1的輸出端 子5的電位設定成，與與施加在信號線1 7的動作信號的電 本紙張尺度適用中國國家標準（CNS ) A4規格（210 X 297公釐） -19- 1226522 A7 B7 五、發明説明（ (請先閲讀背面之注意事項再填寫本頁) 位v in相等，因此，信號線1 7不會有電流出入，可以防止 信號線1 7的電荷量發生變化。並且，在電壓供應電路1含 有高阻抗的第1高電阻3及第2高電阻4，藉此高阻抗可以 有效防止流通於信號線17的電流的一部分流進電壓供應電 路1側。藉此也可以防止信號線1 7的電荷量發生變化。其 結果，第3實施形態的電容測定裝置，在固定連接被測定 電容1 4與固定電容1 5的信號線1 7的電位時，電容測定裝 置的靈敏度也不會降低，可以進行正確的電容測定。 (第4實施形態） 第5圖是表示本發明第4實施形態的包含電位固定裝 置的電容測定裝置的電路圖。參照第5圖，本第4實施形 態的電壓供應電路1是，在上述第3實施形態的架構，於 放大器2的輸入側連接用以對信號線1 7施加動作信號V in 的交流電壓產生器1 3，取代交流電壓產生器7時的例子。 再者，第4實施形態的其他架構與上述第3實施形態相同 〇 經濟部智慧財產局員工消費合作社印製 第4實施形態是如上述，在放大器2的輸入側連接用 以對信號線1 7施加動作信號V in的交流電壓產生器1 3， 藉此可以省略第3實施形態的交流電壓產生器7，可以較第 3實施形態簡化電路架構。 同時，第4實施形態是跟上述第3實施形態同樣，藉 由調節放大器2的放大度A、第1高電阻3的電阻値Ral、 第2高電阻4的電阻値Ra2及端子6的電壓Vs，可以很容 本紙張尺度適用中國國家標準（CNS ) A4規格（210X297公釐） -20- 1226522 A7 ___ B7_ 五、發明説明（1$ (請先閲讀背面之注意事項再填寫本頁) 易將電壓供應電路1的輸出端子5的電壓V a設定成，與 信號線17的動作信號的電壓V in相等。具體上是，使第2 圖所示的放大器2的電阻22及23的電阻値成爲R1 = R2， 藉此使放大器2的放大度A成爲A = 2，是Vs = OV、Ral =Ra2，便可以很容易使電壓供應電路1的輸出端子5的電 壓Va，與信號線1 7的動作信號的V in同電位。 如此，由於將電壓供應電路1的輸出端子5的電壓V a 設定成，與信號線1 7的動作信號的電壓V in相等，因而與 上述第3實施形態同樣，信號線1 7沒有電流出入，可以有 效防止信號線1 7的電荷量發生變化。其結果，在電容測定 裝置固定連信號線17的電位時，電容測定裝置的靈敏度也 不會降低，可以進行正確的電容測定。舉例言之，C s = 2〇 pF、C f = 1 pF、放大器的放大度A = 2、Vin是500 KHz 而數十 mV rms的輸入時，若Ral = Ra2 = 1 ΜΩ，C s的電 壓靈敏度是 -16 dB，但Ral = Ra2 = 100 ΜΩ時，則成爲 - 5 dB，獲得約10 dB的改善。 經濟部智慧財產局員工消費合作社印製 再者，對本次揭示的實施形態應暸解，所有各點均是 例示，並非加上限制。本發明的範圍是如申請專利範圍所 示，不是上述實施形態的說明，而且是包含與申請專利範 圍均等的意義及範圍內的所有變更。 例如，上述實施形態，電壓供應電路1的高阻抗是使 用第1高電阻3及第2高電阻4，但本發明並不限定如此’ 高阻抗也可以利用，例如二極體的逆偏壓特性，或使用電 晶體的截斷狀態等。 本紙張尺度適用中國國家標準（CNS ) A4規格（210 X 297公釐） -21 - 1226522 A7 B7 五、發明説明（1$ (請先閱讀背面之注意事項再填寫本頁) 而上述實施形態，是對具有如第1圖、第3圖、第4 圖及第5圖所示的電路架構的電容測定裝置進行說明，但 本發明並非限定如此，也同樣可以適用於具有其他電路架 構的電容測定裝置。 同時，上述實施形態是說明，固定電容測定裝置的連 接被測定電容14與固定電容15的信號線17的電位時，但 本發明並不限定如此，也可以同時廣泛適用在，固定包含 直接連接第1電容與第2電容的電路架構的電容測定裝置 以外的裝置的電位時。 如以上所述，依據本發明時，固定第1電容與第2電 容間的連接線的電位時，可以防止第1電容與第2電容間 的連接線的電荷量發生變化。其結果，例如在電容測定裝 置，固定第1電容與第2電容間的連接線的電位時，電容 測定裝置的靈敏度不會降低，可以進行正確的電容測定。 【在產業上利用的可能性】 經濟部智慧財產局員工消費合作社印製 如以上所述，本發明的電位固定裝置、電位固定方法 及電容測定裝置，作爲檢測靜電電容的電路及裝置十分有 用，特別是適合作爲電容型麥克風等，各種頻率時靜電電 容量會改變的電容型感測器的檢測電路及檢測裝置。 【圖式的簡單說明】 第1圖是表示本發明第1實施形態的包含電位固定裝 置的電容測定裝置的電路圖。 本紙張尺度適用中國國家標準（CNS ) A4規格（210 X297公釐） -22- 1226522 A7 B7 五、發明説明（2〇 第2圖是表示第1圖所示第1實施形態的電位固定裝 置所含放大器的內部架構的一個例子的電路圖。 (請先閲讀背面之注意事項再填寫本頁) 第3圖是表示本發明第2實施形態的包含電位固定裝 置的電容測定裝置的電路圖。 第4圖是表示本發明第3實施形態的包含電位固定裝 置的電容測定裝置的電路圖。 第5圖是表示本發明第4實施形態的包含電位固定裝 置的電容測定裝置的電路圖。 第6圖是表示傳統的回授阻抗使用電阻時的電容測定 裝置的電路圖。 第7圖是表示第6圖的回授阻抗使用電容時的電容測 定裝置的電路圖。 【圖號說明】 1 :電壓供應電路 2 =放大器 3 :第1高電阻 經濟部智慧財產局員工消費合作社印製 4 :第2高電阻 5 :輸出端子 6 :端子 7 :交流電壓產生器 12 :運算放大電路 1 3 :交流電壓產生器 1 4 :被測定電容 本紙張尺度適用中國國家標準（CNS ) A4規格（210X297公釐） -23- 1226522 A7 B7 五、發明説明（21) 1 5 :固定電容 1 7 :信號線 1 8 :信號輸出端子 2 1 :運算放大電路 2 2、2 3 :電阻 112 :運算放大器 1 1 3 :交流電壓產生器 1 1 4 :被測定電容 115 :回授電容 1 1 6 :回授電阻 1 1 7 :信號線 1 1 8 :信號輸出端子 1 1 9 :電阻 (請先閲讀背面之注意事項再填寫本頁) 經濟部智慧財產局員工消費合作社印製 本紙張尺度適用中國國家標準（CNS ) A4規格（210><297公釐） -24-1. Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs -4- 1226522 A7 ___B7 'V. Description of the invention (2) (Please read the precautions on the back before filling this page) There is a current flowing in the capacitor 114 to be measured. At this time, the input impedance of the operational amplifier H2 is infinite in the ideal state. Therefore, all the current flowing through the measured capacitance 1 1 4 flows through the feedback resistor 1 丨 6. Thereby, the output voltage V out corresponding to the capacitance C s of the measured capacitance 1 1 4 can be output from the signal output terminal 1 1 8. By performing various signal processing based on the output voltage v out of this detection signal, the electrostatic capacitance Cs can be obtained. The conventional capacitance measuring device shown in FIG. 6 uses a feedback resistance 1 1 6 as a feedback resistance. Therefore, the output voltage V out of the signal output terminal 1 1 8 has a frequency characteristic as shown in the following formula (1). . V out = -Rf ((Cd + AC · sin ω c t) · 6; in · cos 6; in t + AC · ω c · cos ω c t · sino in t] V i. . . . . . . . . . . . (1) According to the above formula (1), Vi is the amplitude of the signal V in sent from the AC voltage generator 1 1 3, and in is the angular velocity of the motion signal V i η printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs. C d is the standard capacitance 値 of the measured capacitance 1 14, and AC and ω c are the capacitance 値 and the angular velocity of the capacitance variation of the measured capacitance 1 1 4, respectively. In the above formula (1), the angular velocity ωc of the capacitance change component includes an item proportional to the capacitance 値 AC of the capacitance change component. Therefore, the output voltage V out is proportional to the frequency (ω c / 2 π = f c) of the capacitance variation, and therefore has a frequency characteristic. Therefore, it is necessary to reconfigure the processing circuit in the subsequent stage so that it does not have frequency characteristics. As a result, the circuit scale becomes large. Therefore, some people suggest that the feedback impedance should not use resistors. Instead, use capacitors to form the paper. This paper applies the Chinese National Standard (CNS) A4 specification (210X297 mm) -5- 1226522 Α7 Β7 Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs Explain the technique of (3). Fig. 7 is a circuit diagram showing such a capacitance measuring device. Referring to Fig. 7, the feedback impedance of the capacitance measuring device is constituted by the feedback capacitance 1 1 5. The output voltage V out of this circuit is expressed by the following formula (2). V out = 〔(C d + AC · sin ω c t) / C f〕 V in. . . . . . . . . . . . (2) As shown in the above formula (2), the feedback impedance is formed by the feedback capacitance 115 (capacitance 値: C f). The charge stored in the electrostatic capacitance Cs and the capacitance 値 C f stored in the feedback capacitance 115 The charges will be equal, so the amount of charge on the signal line 1 1 7 can be kept constant. Thereby, the output voltage V out does not include an item proportional to the angular velocity ω c. Therefore, the output of the circuit does not have a dependency on the frequency of the capacitance change, and it is not necessary to reconfigure the processing circuit in the subsequent stage so that it does not depend on the frequency characteristics. As a result, the circuit scale can be prevented from increasing. However, in the technique shown in FIG. 7, when the feedback impedance is formed by the feedback capacitor 1 15, no direct current flows through the signal line 1 1 7 between the feedback capacitor 1 1 5 and the measured capacitor 1 1 4. The signal line 1 1 7 becomes a floating state. Therefore, the potential of the signal line 1 17 becomes unstable, and the circuit output becomes saturated with the power supply voltage, etc., and the circuit cannot operate normally. In order to prevent the above-mentioned problems, a resistor 1 1 9 may be connected between the signal line 1 1 7 and GND as shown in FIG. 7 to thereby fix the potential of the signal line 1 1 7. However, as described above, when the potential is fixed by the resistor 1 1 9, a current may sometimes flow through the resistor 119 when the capacitance is measured. At this time, the amount of charge on the signal line 117 will change, so the sensitivity of the capacitance measuring device will decrease (please read the precautions on the back before filling this page) -J— IJ— Standard (CNS) A4 specification (210X297 mm) -6- 1226522 A7 B7_ 5. Description of the invention (4) Problem points. Therefore, it is difficult to accurately perform capacitance measurement. (Please read the precautions on the back before filling in this page.) When V in is applied to the measured capacitor 1 14 'cover the signal line 1 1 7 with a shield line (not shown), and at the same time, shield it with an imaginary short circuit. The line and signal line 1 1 7 become the same potential, and then the shield line and the signal line 1 1 7 are connected to GND. In the actual operational amplifier 1 1 2, the signal line 1 1 7 will not become Gnd. A slight signal V in will Exist on the signal line 1 1 7. Therefore, stray capacitance is generated between the shielded line and the signal line 1 1. However, due to the influence of this stray capacitance, it is difficult to accurately perform capacitance measurement. The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to provide a potential fixing device capable of preventing a change in the amount of charge of a connection line between a first capacitor and a second capacitor. Another object of the present invention is to provide a capacitance measuring device capable of performing accurate capacitance measurement without reducing the sensitivity when the potential of the connection line between the first capacitor and the second capacitor is fixed. Still another object of the present invention is to provide a potential fixing method capable of preventing a change in the amount of charge in a connection line between a first capacitor and a second capacitor. Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs [Disclosure of the Invention] A potential fixing device of the present invention is used to fix the j-th capacitor and two capacitors directly connected to the second capacitor of the j-th capacitor The potential fixing device for the potential of the connection line is provided with at least two high impedances, and can maintain the total amount of charge of the first capacitor and the second capacitor, and at the same time, 'maintain the potential of the connection line between the two electric valleys at Certainly rampant means of voltage supply. The output terminal of the voltage supply means is connected to two capacitors. The paper size is applicable to the Chinese National Standard (CNS) A4 specification (210X297 mm) '-1226522 A7 B7 V. Description of the invention (5) (Please read the note on the back first Matters then fill in this page). Furthermore, the high impedance of the present invention can be realized by using the reverse bias characteristic of the diode or the cut-off state of the transistor in addition to the high resistance. In the above situation, the potential fixing device can be configured to maintain the total charge of the first capacitor and the second capacitor, and maintain the potential of the connection line between the two capacitors at a certain voltage supply means. At the same time, the output terminal of the voltage supply means is connected to a connection line between the two capacitors, thereby preventing a change in the amount of charge in the connection line between the first capacitor and the second capacitor. In addition, the voltage supply means includes at least two high impedances. This high impedance can effectively prevent a part of the current flowing through the connection line between the two capacitors from flowing into the voltage supply means. This also prevents a change in the amount of charge on the connection line between the first capacitor and the second capacitor. In this way, since the amount of charge on the connection line between the first capacitor and the second capacitor can be prevented from changing, for example, when the potential of the connection line between the first capacitor and the second capacitor is fixed in the capacitance measurement device, The sensitivity will not decrease. As a result, accurate capacitance measurement can be performed. The potential fixation device of the other aspect of the present invention printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs is used to fix the potential of the connection line between the first capacitor and the two capacitors directly connected to the second capacitor of the first capacitor. The potential fixing device is provided with a voltage supply means having at least two high impedances and outputting a potential equal to the potential of the operation signal applied to the connection line. The output terminal of this voltage supply means is a connection line connected between two capacitors. The potential fixation devices in the other situations mentioned above are equipped with potentials that can output and apply the action signal to the connection line of the first capacitor and the second capacitor. This paper is in accordance with the Chinese National Standard (CNS) A4 specification (210X297 mm)- 8- 1226522 A7 B7 V. Description of the invention (6) (Please read the precautions on the back before filling in this page) Means for voltage supply of equal potential, meanwhile, connect the output terminals of this voltage supply means to the first capacitor and the second capacitor The connection line between the capacitors prevents current from flowing in and out of the connection line between the first capacitor and the second capacitor, which can prevent the total charge amount of the connection line from changing. In addition, the voltage supply means includes at least two high impedances, whereby the high impedance can effectively prevent a part of the current flowing through the connection line from flowing into the voltage supply means. This also prevents changes in the total amount of charge on the connection line. In this way, it is possible to prevent the charge amount of the connection line between the first capacitor and the second capacitor from being changed. Therefore, for example, when the potential of the connection line between the first capacitor and the second capacitor is fixed in the capacitance measurement device, the capacitance measurement device The sensitivity will not decrease. As a result, accurate capacitance measurement can be performed. The consumer cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs printed the potential fixation device in one of the above situations or other situations. Preferably, the voltage supply means includes: the first high resistance; the second high resistance directly connected to the first high resistance; A voltage dividing means for outputting a potential divided by a first high resistance and a second high resistance. Furthermore, the "high resistance" of the present invention has a target capacitance of about lpF, a few megaohms or more at a frequency of several hundred MHz or more, a target capacitance of about 1 pF, or a few hundred megaohms at a frequency of several hundred KHz to 1 MHz. That is, "high resistance" means a resistance having a relatively high resistance 値 which is sufficiently larger than the impedance component of the first capacitor and the second capacitor. In this way, if the voltage supply means is configured to include a voltage dividing means that can output a potential divided by the first high resistance and the second high resistance, the resistance of the first high resistance and the second high resistance can be appropriately selected. It is easy to adjust the output potential of the voltage supply means. In the above situation or other situations, the potential fixing device is best. This paper size is applicable to the Chinese National Standard (CNS) A4 specification (210 X297 mm) '-9-1226522 A7 _________ B7 _ _. V. Description of the invention (7) (Please read the precautions on the back before filling out this page) 'Voltage supply means include amplifiers, prescribed voltage application means, i-th high resistance, second high-resistance, and output terminals, amplifiers One terminal of the first high resistance is connected, the other terminal of the first high resistance is connected to the one terminal of the second high resistance, and the other terminal of the first high resistance and one terminal of the second high resistance are connected. There is an output terminal, and the other terminal of the second high-voltage group is connected to a predetermined voltage application means. In this configuration, 'determining the amplifier's amplification, the resistance of the first high resistance and the second high resistance, and the voltage of the predetermined voltage application means, the potential of the output terminal of the voltage supply means can be easily controlled and applied to The potential of the operation signal of the connection line between the first capacitor and the second capacitor is equal to the potential. In another aspect of the present invention, a capacitance measuring device including a potential fixing device, the potential fixing device further includes a first operational amplifier, the first capacitance is a measured capacitance, a connection line between the two capacitors is a signal line, and the first operational amplifier The input terminals are connected to this signal line. The capacitance measuring device printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs in still another aspect is configured to include a potential fixing device having any of the above-mentioned structures, and the first capacitance of the potential fixing device is the measured capacitance. At the same time, the connection line between the two capacitors is a signal line, so that the signal line has no current flowing in and out, so that the total charge amount of the connection line can be prevented from changing. Thereby, when the capacitance of the capacitance measuring device is fixed, the sensitivity of the capacitance measuring device is not lowered when the charge on the connection line between the first capacitor and the second capacitor is fixed. As a result, accurate capacitance measurement can be performed. In still another aspect of the above-mentioned capacitance measuring device including a potential fixing device, it is preferable that the potential fixing device further includes a second operational amplifier. A7 _ B7_ * 5. Description of the invention (8), the output terminal of the second operational amplifier is connected to the second capacitor. In this configuration, the second operational amplifier can be used as a current source. (Please read the precautions on the back before filling this page.) Another potential fixation method of the present invention is to fix the first capacitor and the two capacitors directly connected to the second capacitor of the first capacitor. A method for fixing the potential of a line by using at least two high-resistance divided voltage potentials as output potentials, applying the output potential to a connection line between two capacitors, and fixing the output potential to an output where no current flows in and out of the connection line Potential. The Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs printed the above-mentioned potential fixation method in another situation. When fixing the potential of the connection line between the two capacitors, the potential of the connection line applied between the two capacitors is fixed on the connection line. The output potential of the current flowing in and out can prevent the total total charge amount of the connection line between the first capacitor and the second capacitor from changing. At the same time, the voltage is fixed by at least two output potentials that are divided by the impedance, so that the impedance can effectively prevent a part of the current flowing through the connection line from flowing into the voltage supply means. This also prevents a change in the total amount of charge in the total connection line between the first capacitor and the second capacitor. In this way, it is possible to prevent a change in the amount of charge on the connection line between the first capacitor and the second capacitor. Therefore, for example, in a capacitance measurement device, the potential of the connection line between the first capacitor and the second capacitor is fixed. The sensitivity will not decrease. As a result, accurate capacitance measurement can be performed. In another aspect of the present invention, the potential fixing method is a potential fixing method for fixing the potential of a connection line between the first capacitor and the two capacitors directly connected to the second capacitor of the first capacitor, using at least two A high-resistance divided potential is used as the output potential, and the output potential is applied to two capacitors. The paper size is applicable to the Chinese National Standard (CNS) A4 specification (210X297 mm) -11-1226522 A7 B7 V. Description of the invention (9) And the output potential is set equal to the potential of the operating voltage applied to the connection line between the two capacitors. (Please read the precautions on the back before filling this page.) In the other potential fixation method described above, when fixing the potential of the connection line between the first capacitor and the second capacitor, set the output potential applied to the connection line. It is equal to the potential of the operation signal applied to the connection line between the two capacitors, thereby preventing a change in the total total charge amount of the connection line between the two capacitors. In addition, since the potential is fixed by using at least two high-impedance output potentials, it is possible to effectively prevent a part of the current flowing through the connection line from flowing into the high-impedance side by the high impedance. This also prevents the total amount of charge in the connection from changing. In this way, since the amount of charge on the connection line between the two capacitors can be prevented from changing, for example, when the potential of the connection line between the first capacitor and the second capacitor is fixed in the capacitance measuring device, the sensitivity of the capacitance measuring device does not change. reduce. As a result, accurate capacitance measurement can be performed. In the other aspect or the potential fixing method of the other aspect, it is preferable that either one of the first capacitor and the second capacitor be used as the capacitor to be measured. With this structure, capacitance measurement can be easily performed. Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs [Best Mode for Carrying Out the Invention] The following describes embodiments of the present invention with reference to the drawings. (First Embodiment) FIG. 1 is a circuit diagram showing a capacitance measuring device including a potential fixing device according to a first embodiment of the present invention, and FIG. 2 is a diagram showing an amplifier included in the potential fixing device according to the first embodiment shown in FIG. An example of the internal structure of the paper This paper scale is applicable to the Chinese national standard (CNS> A4 specification (210X297 mm) -12- 1226522 A7 _____B7 _ V. Circuit description of the invention description (1C). First, refer to Figure 1 and 2 The figure illustrates the structure of a capacitance measuring device including a potential fixing device according to the first embodiment. The capacitance measuring device according to the first embodiment includes an operational amplifier circuit 12, an AC voltage generator 13, an electrostatic capacitance Cs, and a capacitance to be measured 14. A fixed capacitor 15 for feedback impedance having a capacitance 当作 C f. The operational amplifier circuit 12 is an example of the "first operational amplifier" of the present invention. The measured capacitance 14 is the "capacitor of the present invention" An example of the "first capacitor" or "second capacitor", and the fixed capacitor 15 is an example of the "first capacitor" or "second capacitor" of the present invention. The measured capacitor 14 and the fixed capacitor 15 The signal line 17 is connected together. The signal line 17 is connected to one terminal of the operational amplifier circuit 12. In addition, the ig 5 tiger line 17 is an example of the "connection line" of the present invention. Furthermore, it is related to the capacitance to be measured. 14 The electrode connected to the opposite side of the signal line 17 is connected to one terminal of the AC voltage generator 13. The electrode connected to the fixed capacitor 15 opposite to the side of the signal line 17 is connected to the signal output Terminals 18. At the same time, the other end of the AC voltage generator 13 is grounded in this embodiment, but it can also be connected to a DC component. Furthermore, the capacitor 14 to be measured is based on the received physical quantities (acceleration, pressure, gas, Light, sound waves, etc.) to change its electrostatic capacitance Cs. The AC voltage generator 13 is used to generate an operation signal v in that is applied to the measured capacitance 14 during capacitance measurement. Here, the first embodiment The capacitance measuring device is used to fix the potential of the signal line 17 using a potential fixing device provided with a voltage supply circuit 1. The voltage supply circuit 1 is an example 1 of the "voltage supply means" of the present invention. Applicable to China National Standard (〇 Chan) 8 4 specifications (210, / 297 mm) '-13- (Please read the precautions on the back before filling this page) Order printed by the Intellectual Property Bureau Staff Consumer Cooperatives of the Ministry of Economic Affairs 1226522 A7 ___B7 V. Description of the invention (11) (Please read the notes on the back before filling this page). The voltage supply circuit 1 contains: amplifier 2 with amplification A; first high resistance 3 with resistance 値 Ral; with resistance 値The second high resistance 4 of Ra2. The Ral of the first high resistance 3 and the Ra2 of the second high resistance 4 both have a resistance of 1 MΩ or more. Furthermore, this resistance 値 is obtained from the frequency used and the detection capacitance. As long as it has a much higher impedance than its characteristic impedance. On the input side of the amplifier 2, another AC voltage generator (other power source) 7 different from the AC voltage generator i 3 is connected. The output side of the amplifier 2 is connected to one terminal of the first high resistance 3. An output terminal 5 is connected between the other terminal of the first high resistance 3 and one terminal of the second station resistance 4. The output terminal 5 of the voltage supply circuit 1 is connected to the letter 5 tiger wire 17 at a point p. A second terminal 6 of the second resistor 4 is provided with a terminal 6. A predetermined potential V s is applied to this terminal 6. This terminal 6 is an example of the "predetermined voltage applying means" of the present invention. At the same time, a voltage v a divided by the resistance division of the first high resistance 3 and the second high resistance 4 is output from the output terminal 5. Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs At the same time, the amplifier 2 has a structure as shown in FIG. 2 for example. That is, the amplifier 2 includes: an operational amplifier circuit 21; a resistor 22 having a resistance 値 R1; and a resistor 23 having a resistance 値 R2. An AC voltage generator 7 is connected to the non-inverting input terminal of the operational amplifier circuit 21 (see Fig. 1). A resistor 22 is connected between the output terminal of the operational amplifier circuit 21 and the inverting input terminal. At the same time, a resistor 22 is connected between the output terminal of the operational amplifier circuit 21 and the inverting input terminal. At the same time, a resistor 23 is connected between the inverting input terminal of the operational amplifier circuit 21 and GND. With this structure, it is easy to obtain the amplifier 2 with an amplification degree A = (R 1 + R 2) / R 2. This paper size applies Chinese national standard (CNS> A4 specification (210X297mm) -14-1226522 A7 B7 V. Description of the invention ((Please read the precautions on the back before filling this page)) The method of fixing the potential is to determine the amplification a of the amplifier 2 'resistance 値 Ra 1 of the first high resistance 3, resistance 値 Ra 2 of the second high resistance 4, 値 Ra2, and the voltage Vs of the terminal 6 so that the operation signal of the signal line 17 is passed The voltage V in is equal to the voltage Va of the output terminal 5 of the voltage supply circuit 1. In addition, the amplification degree A of the amplifier 2 can be appropriately selected by the resistors 値 R 1 and R 2 of the resistors 22 and 23 shown in FIG. 2. The capacitance measurement operation of the capacitance measurement device according to the first embodiment shown in FIG. 1 is to generate an operation signal (voltage ·· V in) from the AC voltage generator 13 and the voltage V in of the operation signal is It is added to both ends of the capacitance to be measured 14. By this, a current flows through the capacitance to be measured 14. At this time, the input impedance of the operational amplifier circuit 12 is infinite in an ideal state, and therefore, it flows through the capacitance to be measured 1 4 The current will all flow through the solid The fixed capacitance 15 is used to output the output voltage V out corresponding to the electrostatic capacitance C s of the measured capacitance 14 from the signal output terminal 18. By performing various signal processing based on the output voltage V out of the detection signal, Obtain the electrostatic capacitance C s of the measured capacitance 14. Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs. The first embodiment is as described above. It is provided with a signal line that connects the measured capacitance 14 to the fixed capacitance 15. 17 The voltage supply circuit 1 that applies an AC voltage for potential fixation and sets the potential of the output terminal 5 of the voltage supply circuit 1 to be equal to the potential V in of the operation signal applied to the signal line 17 Since no current flows in and out of the signal line 17, it is possible to prevent a change in the charge amount of the signal line 17. Also, since the voltage supply means 1 includes the first high resistance 3 and the second high resistance 4 with high impedance, the high impedance Can effectively prevent the circulation of this paper. Applicable Chinese National Standard (CNS) A4 specification (210X297 mm) -15- 1226522 A7 __________ B7 V. Description of the invention (a part of the current of line 17) The voltage flooding means 1 side. This can also prevent the charge of the connection line 17 from changing. (Please read the precautions on the back before filling this page.) The first embodiment is as described above for the signal line 1 7 Since no charge is injected or discharged, the total charge of the signal line 17 can be prevented from changing. Here, the total charge of the measured capacitor 14 and the fixed capacitor 15 can be prevented. As shown in FIG. 1, from The operation signal (voltage: V i η) sent from the AC voltage generator 13 is maintained at a certain level. Therefore, the voltage V s applied to the capacitor J 4 to be measured is also a certain amount. However, since the capacitance to be measured 14 is a capacitance detection section, the capacitance 値 C s of the capacitance 14 to be measured changes. A change in the capacitance 値 C s of the capacitor 14 to be measured becomes a change in the charge amount Q s of the capacitor 14 to be measured. In the first embodiment, as described above, no charge is injected or discharged to the signal line 17, and therefore, the sum of the amount of charge Qf stored in the fixed capacitor 15 and the amount of charge Qs stored in the capacitor 14 to be measured is constant. Therefore, an increase or decrease in the charge amount Q s of the capacitor 14 to be measured appears as a decrease or increase in the charge amount Q f of the fixed capacitor 15. The change (decrease) in the amount of charge Q f of the fixed capacitor 15 printed by the employee's consumer cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs is constant because the capacitance 値 C f of the fixed capacitor 15 is constant, so it appears as a voltage 成为 V f of the fixed capacitor 15. Change (decrease or increase). The output of the voltage V f applied to the fixed capacitor 15 becomes V out from the signal output terminal 18 and is output. That is, in the capacitance measuring device of the first embodiment, there is a charge transmission and reception between the capacitance 値 C s of the capacitance 14 to be measured and the capacitance 値 C f of the fixed capacitance 15, but as described above, no signal is injected into the signal line 17. Since the electric charge flows out, the total amount of electric charges in the measured capacitor 14 and the fixed capacitor 15 is constant. With this, the total of the measured capacitors 1 4 and fixed capacitors 15 can be used. The paper size is applicable to China National Standard (CNS) A4 specifications (210X297 mm) -16- 1226522 A7 B7 V. Description of the invention ((Please read first Note on the back, please fill in this page again.) The total charge is kept constant, and at the same time, a fixed potential is supplied to the signal line 17 by the voltage supply circuit 1. Therefore, the signal line 1 4 of the measured capacitance 14 and the fixed capacitance 15 are fixedly connected. The capacitance of the capacitance measuring device does not decrease even when the potential is equal to the potential. As a result, accurate capacitance measurement can be performed. (Second Embodiment) Fig. 3 shows a capacitance measuring device including a potential fixing device according to a second embodiment of the present invention. Referring to FIG. 3, the voltage supply circuit 1 of the second embodiment is an AC voltage of the structure of the first embodiment, which is connected to the input side of the amplifier 2 and can apply an operation signal v in to the signal line 17 The generator 13 is an example when the AC voltage generator 7 is replaced. The other structure of the second embodiment is the same as that of the first embodiment. The second embodiment is as described above. An input side of the amplifier 2 is connected to an AC voltage generator 13 for applying an operation signal V in to the signal line 17, thereby making it possible to omit the AC voltage generator 7 of the first embodiment and simplify the circuit structure compared to the first embodiment. Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs, the second embodiment is the same as the first embodiment described above. By adjusting the amplification degree A of the amplifier 2, the resistance 値 Ral of the first high resistance 3, and the second high resistance The resistance 値 Ra2 of 4 and the voltage Vs of the terminal 6 can easily set the voltage V a of the output terminal 5 of the voltage supply circuit 1 to be equal to the voltage V in of the operation signal of the signal line 17. Specifically, the first 2 The resistance 値 of the resistors 22 and 23 of the amplifier 2 shown in the figure becomes R1 = R2, so that the amplification degree A of the amplifier 2 becomes A = 2, and Vs = 〇V and Ral = Ra2, and the voltage can be easily adjusted. The paper size of the output terminal 5 of the supply circuit 1 applies the Chinese National Standard (CNS) A4 specification (210X297 mm) -17-1226522 A 7 _ B7_ V. Description of the invention (β pressure Va becomes Va = Vin. So, because The output of the voltage supply circuit 1 The voltage V a of the terminal 5 is set to be equal to the voltage V in of the operation signal of the signal line 17. Therefore, similar to the first embodiment, the signal line 17 has no current flowing in and out, and the charge of the signal line 17 can be effectively prevented. As a result, even when the capacitance of the capacitance measuring device is fixed to the potential of the signal line 17, the sensitivity of the capacitance measuring device is not reduced, and accurate capacitance measurement can be performed. (Third Embodiment) Fig. 4 shows this A circuit diagram of a capacitance measuring device including a potential fixing device according to a third embodiment of the invention. First, the structure of a capacitance measuring device including a potential fixing device according to a third embodiment will be described with reference to Fig. 4. The third embodiment includes an operational amplifier circuit 1 which is a current source, an operational amplifier circuit 1 in a virtual short-circuit state, an AC voltage generator 1, a measured capacitor 1, a fixed capacitor 15, and the like. The operational amplifier circuit 11 is an example of the "second operational amplifier circuit" of the present invention. The measured capacitance 14 and the fixed capacitance 15 are connected by a signal line 17. The signal line 17 is connected to one input terminal of the operational amplifier circuit 12. The AC voltage generator 13 is an input terminal connected to the other side of the operational amplifier circuit 12. Here, the third embodiment uses a potential fixing device provided with a voltage supply circuit 1 to fix the potential of the signal line 17. The structure of the voltage supply circuit 1 and the structure of the included amplifier 2 are the same as those of the first embodiment. That is, the voltage supply circuit 1 contains: Amplifier 2 with magnification A. This paper size applies the Chinese National Standard (CNS) A4 specification (210X297 mm) (please read the precautions on the back before filling this page). Printed by the Consumer Cooperatives of the Ministry of Intellectual Property Bureau -18-1226522 A7 B7 V. Description of the invention (10 (Please read the precautions on the back before filling this page), 1st high resistance 3, 2nd high resistance 4. In amplifier 2 The input side is connected to another AC voltage generator 7 different from the AC voltage generator 13. The output side of the amplifier 2 is connected to one terminal of the first high resistance 3. The other terminal of the first high resistance 3, An output terminal 5 of the voltage supply circuit 1 is provided. The output terminal 5 of the voltage supply circuit 1 is connected to the signal line 17. The other end of the second high resistance 4 is provided with a terminal 6. This terminal 6 is applied with a predetermined potential Vs. At the same time A voltage V a output from the output terminal 5 and divided by the resistance of the first high resistance 3 and the second high resistance 4. The potential fixing method of the capacitance measuring device according to the third embodiment is to determine the amplification degree of the amplifier 2 A, the first high power Resistance 3 of resistance 値 Ra 1, resistance of second high resistance 4 値 Ra2 and voltage Vs of terminal 6 make the voltage V in of the operating signal flowing through signal line 17 to the voltage of output terminal 5 of voltage supply circuit 1 V a is equal. The capacitance measurement operation of the capacitance measurement device of the third embodiment printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs in the third embodiment shown in FIG. 4 is that the operational amplifier circuit 12 is generated from an AC voltage due to a virtual short circuit. The voltage V in (action signal) generated by the device 13 is applied to the signal line 17. This causes current to flow through both ends of the capacitor 14 to be measured. The signal output terminal 18 outputs an electrostatic capacitance corresponding to the capacitor 14 to be measured. The output voltage V out of C s. By applying various signal processing to this output voltage V out, the capacitance C s of the measured capacitance 14 can be obtained. As described above, the third embodiment is provided for connection to be measured. The connection line 17 between the capacitor 14 and the fixed capacitor 15 is a voltage supply circuit 1 that applies an AC voltage for a fixed potential. At the same time, the potential of the output terminal 5 of the voltage supply circuit 1 is set to be equal to that applied to the signal line 17 The paper size of the electronic signal of the motion signal applies to the Chinese National Standard (CNS) A4 specification (210 X 297 mm) -19- 1226522 A7 B7 V. Description of the invention ((Please read the precautions on the back before filling this page) Bit v in Equal, therefore, there is no current flowing in and out of the signal line 17, which can prevent the amount of charge on the signal line 17 from changing. Also, the voltage supply circuit 1 includes the first high resistance 3 and the second high resistance 4 with high impedance. This high impedance can effectively prevent a part of the current flowing through the signal line 17 from flowing into the voltage supply circuit 1 side. This can also prevent the charge amount of the signal line 17 from changing. As a result, in the capacitance measuring device of the third embodiment, when the potential of the signal line 17 of the measured capacitance 14 and the fixed capacitance 15 is fixedly connected, the sensitivity of the capacitance measuring device is not reduced, and accurate capacitance measurement can be performed. . (Fourth Embodiment) Fig. 5 is a circuit diagram showing a capacitance measuring device including a potential fixing device according to a fourth embodiment of the present invention. Referring to FIG. 5, the voltage supply circuit 1 of the fourth embodiment is an AC voltage generator connected to the input side of the amplifier 2 to apply an operation signal V in to the signal line 17 in the structure of the third embodiment. 1 3, an example when replacing the AC voltage generator 7. In addition, the other structure of the fourth embodiment is the same as that of the third embodiment described above. The fourth embodiment is printed by the employee consumer cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs as described above, and is connected to the input side of the amplifier 2 for the signal line 17 By applying the AC voltage generator 1 3 of the operation signal Vin, the AC voltage generator 7 of the third embodiment can be omitted, and the circuit structure can be simplified compared with the third embodiment. At the same time, the fourth embodiment is similar to the third embodiment described above. By adjusting the amplification degree A of the amplifier 2, the resistance 値 Ral of the first high resistance 3, the resistance 値 Ra2 of the second high resistance 4, and the voltage Vs of the terminal 6 It can be well tolerated that this paper size applies the Chinese National Standard (CNS) A4 specification (210X297 mm) -20-1226522 A7 ___ B7_ V. Description of the invention (1 $ (Please read the precautions on the back before filling this page) The voltage V a of the output terminal 5 of the voltage supply circuit 1 is set to be equal to the voltage V in of the operating signal of the signal line 17. Specifically, the resistance 値 of the resistors 22 and 23 of the amplifier 2 shown in FIG. 2 is R1 = R2, so that the amplification degree A of the amplifier 2 becomes A = 2, Vs = OV, and Ral = Ra2, so that the voltage Va of the output terminal 5 of the voltage supply circuit 1 can be easily compared with the signal line 17 The V in of the operation signal is at the same potential. In this way, the voltage V a of the output terminal 5 of the voltage supply circuit 1 is set to be equal to the voltage V in of the operation signal of the signal line 17, so it is the same as the third embodiment. There is no current flowing in and out of the signal line 1 and 7. The amount of charge on line 17 changes. As a result, when the capacitance of the capacitance measurement device is fixed to the potential of the signal line 17, the sensitivity of the capacitance measurement device does not decrease, and accurate capacitance measurement can be performed. For example, C s = 2 〇pF, C f = 1 pF, amplifier's amplification A = 2, Vin is 500 KHz and tens of mV rms input, if Ral = Ra2 = 1 ΜΩ, the voltage sensitivity of C s is -16 dB, but Ral = Ra2 = 100 ΜΩ, it becomes -5 dB, which is an improvement of about 10 dB. Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs, the implementation form disclosed this time should be understood, all points are examples, It is not a limitation. The scope of the present invention is as shown in the scope of the patent application, not the description of the above embodiment, and includes all changes within the meaning and scope equivalent to the scope of the patent application. For example, in the above embodiment, the voltage supply circuit The high impedance of 1 is the use of the first high resistance 3 and the second high resistance 4, but the present invention is not limited to this. The high impedance can also be used, such as the reverse bias characteristic of a diode or the cut-off state using a transistor. Etc. This paper size applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm) -21-1226522 A7 B7 V. Description of the invention (1 $ (please read the precautions on the back before filling this page) and the above implementation The form describes a capacitance measuring device having a circuit architecture as shown in FIGS. 1, 3, 4, and 5. However, the present invention is not limited to this, and it can also be applied to other circuit architectures. Capacitance measuring device. In the meantime, the above embodiment is described when the potential of the fixed capacitance measuring device is connected to the potential of the signal line 17 of the measured capacitance 14 and the fixed capacitance 15. When the potential of a device other than the capacitance measuring device in the circuit structure of the first capacitor and the second capacitor is used. As described above, according to the present invention, when the potential of the connection line between the first capacitor and the second capacitor is fixed, the charge amount of the connection line between the first capacitor and the second capacitor can be prevented from changing. As a result, for example, in the capacitance measuring device, when the potential of the connection line between the first capacitor and the second capacitor is fixed, the sensitivity of the capacitance measuring device is not reduced, and accurate capacitance measurement can be performed. [Possibility of industrial use] Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs, as described above, the potential fixing device, potential fixing method, and capacitance measuring device of the present invention are very useful as circuits and devices for detecting electrostatic capacitance. In particular, it is suitable as a detection circuit and a detection device for a capacitive sensor, such as a condenser microphone, whose electrostatic capacitance changes at various frequencies. [Brief description of the drawings] Fig. 1 is a circuit diagram showing a capacitance measuring device including a potential fixing device according to a first embodiment of the present invention. This paper size applies the Chinese National Standard (CNS) A4 specification (210 X297 mm) -22-1226522 A7 B7 V. Description of the invention (2) Figure 2 shows the potential fixing device shown in the first embodiment shown in Figure 1. A circuit diagram of an example of an internal structure including an amplifier. (Please read the precautions on the back before filling out this page.) Figure 3 is a circuit diagram showing a capacitance measuring device including a potential fixing device according to a second embodiment of the present invention. Figure 4 FIG. 5 is a circuit diagram showing a capacitance measuring device including a potential fixing device according to a third embodiment of the present invention. FIG. 5 is a circuit diagram showing a capacitance measuring device including a potential fixing device according to a fourth embodiment of the present invention. FIG. 6 is a diagram showing a conventional A circuit diagram of a capacitance measuring device when a feedback impedance uses a resistor. Fig. 7 is a circuit diagram of a capacitance measuring device when a feedback impedance is a capacitor in Fig. 6. [Illustration of drawing number] 1: Voltage supply circuit 2 = Amplifier 3: Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs of the 1st High Resistance 4: 2nd High Resistance 5: Output Terminal 6: Terminal 7: AC Voltage Generator 12: Operation Amplifying circuit 1 3: AC voltage generator 1 4: Capacitance to be measured The paper size is applicable to Chinese National Standard (CNS) A4 specification (210X297 mm) -23- 1226522 A7 B7 V. Description of the invention (21) 1 5: Fixed capacitor 1 7: signal line 1 8: signal output terminal 2 1: operational amplifier circuit 2 2, 2 3: resistor 112: operational amplifier 1 1 3: AC voltage generator 1 1 4: measured capacitor 115: feedback capacitor 1 1 6: feedback resistance 1 1 7: signal line 1 1 8: signal output terminal 1 1 9: resistance (please read the precautions on the back before filling this page) The paper printed by the employee consumer cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs applies China National Standard (CNS) A4 Specification (210 > < 297 mm) -24-