TW201315970A - Capacity measuring circuit - Google Patents
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本發明係有關於一種電容量測電路，其係尤指一種可利用簡單的電路而短時間量測電容值的變化之電容量測電路。
The present invention relates to a capacitance measuring circuit, and more particularly to a capacitance measuring circuit capable of measuring a change in a capacitance value in a short time using a simple circuit.
按，傳統上，多半以機械式開關來實現使用者控制介面。由於使用者需直接接觸到傳統機械開關，傳統機械開關才可回應於使用者之控制指令而進行操作，傳統機械式裝置容易在使用者操作過程中發生壞損。目前，已發展出觸控式開關，觸控式開關可以是電容式開關。
為了提升使用上的便利性，已研發出觸控面板(touch panel)或顯示觸控面板(同時具有顯示與觸控的功能)。觸控面板或顯示觸控面板可接受使用者的輸入、點選等操作。觸控面板或顯示觸控面板可應用於各樣電子裝置當中，例如行動電話中。如此，可讓使用者直接在觸控面板或顯示觸控面板上點選畫面來進行操作，藉此提供更為便捷且人性化的操作模式。觸控面板或顯示觸控面板有數種，電容式觸控面板或顯示觸控面板是其中一種。
當使用者操作電容式觸控面板、電容式顯示觸控面板、或電容式開關時，其內部的待測電容的電容值會隨使用者操作而發生變化。依此，可偵測到使用者的操作。然而，如何設計出可有效地偵測待測電容之電容值變化之電容值測量電路，以提升電容式觸控面板、電容式顯示觸控面板、或電容式開關之性能乃為業界不斷致力的方向之一。
然而，現今有數種方法可以用來偵測電容量，例如利用電壓，電流或頻率的變化，經由計算可推算之電容量的變化，例如美國專利號第7,307,485號中，其藉由RC振盪方式來偵測電容或電容值的變化量，當電容量改變時，其所振盪出來的頻率也會隨之改變，但此方法需消耗大量的電力，並且容易受外界雜訊的干擾。因此，如何針對上述問題而提出一種新穎電容量測電路，使可解決上述之問題。
Press, traditionally, the user control interface is mostly implemented with a mechanical switch. Since the user needs to directly contact the traditional mechanical switch, the traditional mechanical switch can operate in response to the user's control command, and the conventional mechanical device is liable to be damaged during the user's operation. At present, a touch switch has been developed, and the touch switch can be a capacitive switch.
In order to improve the convenience of use, a touch panel or a display touch panel (having a function of display and touch) has been developed. The touch panel or the display touch panel can accept user input, click, and the like. The touch panel or the display touch panel can be applied to various electronic devices, such as a mobile phone. In this way, the user can directly operate the screen by directly clicking on the touch panel or the display touch panel, thereby providing a more convenient and user-friendly operation mode. There are several types of touch panels or display touch panels, and a capacitive touch panel or a display touch panel is one of them.
When a user operates a capacitive touch panel, a capacitive display touch panel, or a capacitive switch, the capacitance of the internal capacitance to be tested changes with the user's operation. Accordingly, the user's operation can be detected. However, how to design a capacitance value measuring circuit that can effectively detect the change of the capacitance value of the capacitor to be tested to improve the performance of the capacitive touch panel, the capacitive display touch panel, or the capacitive switch is continuously dedicated to the industry. One of the directions.
However, there are several methods available today for detecting capacitance, such as changes in voltage, current, or frequency, through calculations of inferred changes in capacitance, such as in US Patent No. 7,307,485, which is by RC oscillation. When the capacitance or capacitance value is detected, the frequency oscillated will change when the capacitance changes. However, this method consumes a large amount of power and is easily interfered by external noise. Therefore, how to solve the above problems and propose a novel capacitance measuring circuit, so that the above problems can be solved.
本發明之目的之一，在於提供一種電容量測電路，其藉由一處理電路的電路結構電路，而可節省電路面積進而達到節省成本的目的，並增加量測精確度的目的。
本發明之目的之一，在於提供一種電容量測電路，其利用電壓源而可以使用簡單的電路達到電容量測的目的。
本發明之電容量測電路包含一待測電容與一參考電容。待測電容耦接一焊墊，並用以量測一物件接觸待測電容，而產生一感測電壓；參考電容耦接待測電容，以及處理電路耦接待測電容與參考電容，並依據感測電壓與一門檻值，調整感測電壓之位準，當感測電壓小於門檻值，並依據感測電壓與門檻值的差異判斷物件是否接觸待測電容。如此，本發明藉由處理電路的電路結構電路，而可節省電路面積進而達到節省的目的。
One of the objects of the present invention is to provide a capacitance measuring circuit which can save circuit area by using a circuit structure circuit of a processing circuit, thereby achieving cost saving and increasing measurement accuracy.
It is an object of the present invention to provide a capacitance measuring circuit that utilizes a voltage source to achieve capacitance measurement using a simple circuit.
The capacitance measuring circuit of the present invention comprises a capacitor to be tested and a reference capacitor. The capacitor to be tested is coupled to a solder pad and is used for measuring an object to contact the capacitor to be tested to generate a sensing voltage; the reference capacitor coupling receives the measuring capacitor, and the processing circuit couples the receiving capacitance and the reference capacitor, and according to the sensing voltage And a threshold value, adjust the level of the sensing voltage, when the sensing voltage is less than the threshold value, and determine whether the object contacts the capacitance to be tested according to the difference between the sensing voltage and the threshold value. Thus, the present invention can save the circuit area and achieve the purpose of saving by the circuit structure circuit of the processing circuit.
茲為使 貴審查委員對本發明之結構特徵及所達成之功效有更進一步之瞭解與認識，謹佐以較佳之實施例及配合詳細之說明，說明如後：
請參閱第二圖，係為本發明之電容量測電路的一實施例的電路圖。如圖所示，本發明之電容量測電路1包含一待測電容10、一參考電容20與一處理電路30。待測電容10耦接一焊墊12，該待測電容10用以量測物件(圖中未示，例如手指或觸控筆等)接觸待測電容10，如第一A圖與第一B圖所示，處理電路30可設置於一晶片2內，而待測電容10與參考電容20則設置於晶片2之外部，並且待測電容10與參考電容20分別經由焊墊12與焊墊22而耦接至晶片2內的處理電路30，其中，如第一A圖所示，待測電容10可為觸控焊墊(touch pad)或觸控感測器(touch sensor)，並且待測電容10與焊墊12之間可使用印刷電路板佈線(PCB trace)連接。待測電容10量測物件而產生一感測電壓VS，參考電容20耦接待測電容10，處理電路30耦接待測電容10與參考電容20，並依據感測電壓VS與一門檻值Vb，調整感測電壓VS之位準，當感測電壓VS小於門檻值Vb，並依據感測電壓VS與門檻值Vb的差異判斷物件是否接觸待測電容10。
接上所述，由於物件未觸碰待測電容10時，待測電容10上的電容值為一背景電容(background capacitor)的大小，即背景電容大小為待測電容10對接地端的電壓或電容量測電路1本身對接地端的電壓等，也就是如下列公式所示：
CX=Cb…………(1)
其中，CX表示為待測電容上的電容值，Cb表示為背景電容的電容值大小。當物件接觸待測電容10時，待測電容10上的電容值為背景電容的電容值加上物件觸碰待測電容10時，物件對接地端的電容值，即如下列公式所示：
CX=Cb＋Cf…………(2)
其中，Cf表示為物件對接地端的電容值。
再者，本發明之處理電路30依據感測電壓VS與一門檻值Vb，調整感測電壓VS之位準，當該感測電壓VS小於門檻值Vb，並依據感測電壓VS與門檻值Vb的差異判斷物件是否接觸待測電容10，即處理電路30控制參考電容20上的電壓對待測電容10進行充電，並適時控制待測電容10對接地端進行放電，而可調整參考電容20上之感測電壓VS的位準，即本發明之電容量測電路1更包含一第一開關40、一第二開關42與一第三開關44。第一開關40耦接於一電源VCC與參考電容20之間，並受控於處理電路30，當第一開關40導通時，電源VCC係對參考電容20進行充電，也就是說處理電路30產生一第一控制訊號P1並傳送至第一開關40，以導通第一開關40，使電源VCC對參考電容20進行充電。
第二開關42耦接於待測電容10與參考電容20之間，並受控於處理電路30，即處理電路30產生一第二控制訊號P2，並傳送第二開關42，以導通第二開關42，使待測電容10分享參考電容20上的電壓。第三開關44耦接於待測電容10與一接地端之間，並受控於處理電路30，其中，處理電路30係依序控制第一開關40、第二開關42與第三開關44導通。即如第三圖所示，為本發明之電容量測電路的一實施例的波形圖。處理電路30係先產生第一控制訊號P1，使電源VCC對參考電容20進行充電，讓參考電容20之電壓充電至電源VCC的電壓，之後，處理電路30產生第二控制訊號P2，此時，處理電路30停止產生並傳送第一控制訊號P1，處理電路30傳送第二控制訊號P2至第二開關42，讓待測電容10分享參考電容20上的電壓，接著，處理電路30產生第三控制訊號P3，此時，處理電路30停止產生並傳送第二控制訊號P2，處理電路30傳送第三控制訊號P3至第三開關44，導通第三開關44，使待測電容10之電壓對接地端進行放電。
基於上述，處理電路30係依序切換第二開關42與第三開關44數次，而使參考電容20間的感測電壓VS逐漸減少，直到感測電壓VS小於門檻值Vb為止，由上述公式(1)與公式(2)可知，物件觸碰待測電容10時的電容值與物件未觸碰待測電容10時的電容值並不相同，而物件觸碰待測電容10時，最後感測電壓VS與門檻值Vb的差值V2與物件未觸碰待測電容10時，最後感測電壓VS與門檻值Vb的差值V1並不相同，如此，本實施例之處理電路30可藉由前後最後感測電壓VS與門檻值Vb的差值不同而決定物件是否觸碰待測電容10，如第三圖所示，實線表示物件未觸碰待測電容10的訊號，而虛線表示為物件觸碰待測電容10的訊號，所以，當物件觸碰待測電容10時，最後感測電壓VS與門檻值Vb的差值V2會大於物件未觸碰待測電容10時最後感測電壓VS與門檻值Vb的差值V1，所以，處理電路30藉由前後次感測電壓VS與門檻值Vb之間差異而得知物件是否接觸待測電容10，即在前後次感測電壓VS與門檻值Vb之間差異過大時，則表示物件觸碰待測電容10。
請復參閱第二圖，本發明之處理電路30包含一類比數位轉換單元32與一處理單元34。類比數位轉換單元32具有一第一輸入端與一第二輸入端，第一輸入端耦接待測電容10與參考電容20，並接收感測電壓VS，第二輸入端接收門檻值Vb，類比數位轉換單元32依據感測電壓VS與門檻值Vb產生一數位資料。處理單元34耦接類比數位轉換單元32，並依據數位資料控制感測電壓VS的準位與判斷物件接觸待測電容10，即數位資料可相當於感測電壓VS與門檻值Vb之間差異值，所以，處理單元34可以透過數位資料而得知感測電壓VS與門檻值Vb之間差異值，並藉由前後數位資料的不同而得知物件是否接觸待測電容10。
另外，本發明之電容量測電路1更包含一差分放大器36。差分放大器36具有一第一輸入端、一第二輸入端與二輸出端，差分放大器36之第一輸入端耦接參考電容20與待測電容10，以接收感測訊號VS，差分放大器36之第二輸入端接收門檻值Vb，差分放大器36用以放大感測訊號VS與門檻值Vb的差值，並經差分放大器36之二輸出端傳送該差值至類比數位轉換單元 32，以進行轉換。
基於上述，本發明之電容量測電路1係利用物件觸碰待測電容10時，最後感測電壓VS與門檻值Vb的差值V2與物件未觸碰待測電容10時，最後感測電壓VS與門檻值Vb的差值V1而決定物件是否觸碰待測電容10，其物件未觸碰待測電容10時，感測電壓VS與門檻值Vb的差值V1的公式如下所示：
V1=Vb-VS
= Vb- (Vcc-K*Cb)----------(3)
其中，K為差分放大器36所放大訊號的倍數，而物件觸碰待測電容10時，感測電壓VS與門檻值Vb的差值V2的公式如下所示：
V2= Vb-VS
= Vb- (Vcc-K*(Cb+Cf))----------(4)
上述感測電壓VS與門檻值Vb的差值V1與感測電壓VS與門檻值Vb的差值V2經由類比數位轉換器32轉換成數位資料，即類比數位轉換器32將上述差值V1與差值V2轉換成數位資料可表示如下：
Qadc1=quant(V1)-------------------(5)
Qadc2=quant(V2)-------------------(6)
本發明之處理電路30可以利用Qadc1與Qadc2的數值差，而判斷出待測電容10是否被物件所觸碰，其可表示如下：
Qadc2-Qadc1=quant(V2)-quant(V1)
=quant(K*Cf)---------(7)
由第(7)式可知，本發明之電容量測電路1可忽略背景電容的Cb因素而量測出物件是否觸碰待測電容10，即可有效且精確地量測出物件對接地端的電容值Cf，以達到增加量測精確度的目的。
此外，本發明之電容量測電路1除了可利用處理電路30係依序切換第二開關42與第三開關44數次，而使參考電容20間的感測電壓VS逐漸減少，直到感測電壓VS小於門檻值Vb為止，而得知物件是否觸碰待測電容10之外，反之，請參閱第四圖，為本發明之電容量測電路之另一實施例的電路圖。如圖所示，本實施係之電容量測電路5與第二圖之實施例不同之處，在於本實施例電容量測電路5的一待測電容50、一參考電容60與一第三開關74皆耦接電源端Vcc，而本實施例之一第一開關70耦接接地端，本實施例之量測方法如第五圖所示，其先將參考電容60之起始電壓調整為零，並由參考電容60分享待測電容50上的電荷，處理電路80可利用一第一開關70、一第二開關72與第三開關74使參考電容60上的電壓VS由零被充電至大於門檻值Vb後，而依據前後電壓VS與門檻值Vb之間差異，而得知物件是否觸碰待測電容50，其中，處理電路80判斷前後電壓VS與門檻值Vb之間差異的方式，該技術領域具有通常知識者可依據上述公式可容易推想而知，故於此將不再加以贅述。
綜上所述，本發明之電容量測電路藉由一處理電路耦接一待測電容與一參考電容，並依據待測電容與參考電容所產生之一感測電壓與一門檻值，調整感測電壓之位準，當感測電壓小於門檻值，並依據感測電壓與門檻值的差異判斷物件是否接觸待測電容。如此，本發明藉由處理電路的電路結構電路，而可節省電路面積進而達到節省的目的。
本發明係實為一具有新穎性、進步性及可供產業利用者，應符合我國專利法所規定之專利申請要件無疑，爰依法提出發明專利申請，祈 鈞局早日賜准專利，至感為禱。
惟以上所述者，僅為本發明之一較佳實施例而已，並非用來限定本發明實施之範圍，舉凡依本發明申請專利範圍所述之形狀、構造、特徵及精神所為之均等變化與修飾，均應包括於本發明之申請專利範圍內。
In order to provide a better understanding and understanding of the structural features and the achievable effects of the present invention, the preferred embodiments and detailed descriptions are provided as follows:
Please refer to the second figure, which is a circuit diagram of an embodiment of the capacitance measuring circuit of the present invention. As shown in the figure, the capacitance measuring circuit 1 of the present invention comprises a capacitor 10 to be tested, a reference capacitor 20 and a processing circuit 30. The capacitor 10 to be tested is coupled to a pad 12, and the capacitor 10 to be tested is used to measure an object (not shown, such as a finger or a stylus pen) to contact the capacitor 10 to be tested, such as the first A picture and the first B. As shown, the processing circuit 30 can be disposed in a wafer 2, and the capacitor 10 to be tested and the reference capacitor 20 are disposed outside the wafer 2, and the capacitor 10 to be tested and the reference capacitor 20 are respectively connected via the pad 12 and the pad 22 The processing circuit 30 is coupled to the processing circuit 30, wherein, as shown in FIG. A, the capacitor 10 to be tested may be a touch pad or a touch sensor, and is to be tested. A printed circuit board (PCB trace) connection can be used between the capacitor 10 and the pad 12. The capacitor 10 to be tested measures the object to generate a sensing voltage V S , the reference capacitor 20 is coupled to the receiving capacitor 10, and the processing circuit 30 is coupled to the receiving capacitor 10 and the reference capacitor 20, and according to the sensing voltage V S and a threshold V b , adjusting the level of the sensing voltage V S , when the sensing voltage V S is less than the threshold value V b , and determining whether the object contacts the capacitor 10 to be tested according to the difference between the sensing voltage V S and the threshold value V b .
In addition, when the object does not touch the capacitor 10 to be tested, the capacitance value of the capacitor 10 to be tested is a background capacitor, that is, the background capacitor is the voltage or capacitance of the capacitor 10 to the ground. The voltage of the measuring circuit 1 itself to the ground terminal, etc., is as shown in the following formula:
C X =C b ............(1)
Where C X is the capacitance value on the capacitor to be tested, and C b is the capacitance value of the background capacitor. When the object contacts the capacitor 10 to be tested, the capacitance value of the capacitor 10 to be tested is the capacitance value of the background capacitor plus the capacitance value of the object to the ground terminal when the object touches the capacitor 10 to be tested, as shown by the following formula:
C X =C b +C f ............(2)
Where C f is the capacitance value of the object to the ground.
Furthermore, processing circuit 30 according to the present invention sense voltage V S with a threshold value V b, adjust the level of the sense voltage V S, when the sense voltage V S is less than the threshold value V b, and a voltage according to the sensing The difference between V S and the threshold value V b determines whether the object contacts the capacitor 10 to be tested, that is, the processing circuit 30 controls the voltage on the reference capacitor 20 to charge the capacitor 10 to be measured, and timely controls the capacitor 10 to be tested to discharge the ground terminal. The level of the sensing voltage V S on the reference capacitor 20 can be adjusted, that is, the capacitance measuring circuit 1 of the present invention further includes a first switch 40, a second switch 42 and a third switch 44. The first switch 40 is coupled between a power source V CC and the reference capacitor 20 and is controlled by the processing circuit 30. When the first switch 40 is turned on, the power source V CC charges the reference capacitor 20, that is, the processing circuit. 30 generates a first control signal P 1 and transmits it to the first switch 40 to turn on the first switch 40 to cause the power source V CC to charge the reference capacitor 20 .
The second switch 42 is coupled between the capacitor 10 to be tested and the reference capacitor 20, and is controlled by the processing circuit 30, that is, the processing circuit 30 generates a second control signal P 2 and transmits the second switch 42 to turn on the second The switch 42 causes the capacitor 10 to be tested to share the voltage on the reference capacitor 20. The third switch 44 is coupled between the capacitor 10 to be tested and a ground terminal, and is controlled by the processing circuit 30. The processing circuit 30 sequentially controls the first switch 40, the second switch 42 and the third switch 44 to be turned on. . That is, as shown in the third figure, it is a waveform diagram of an embodiment of the capacitance measuring circuit of the present invention. The processing circuit 30 first generates the first control signal P 1 , causes the power source V CC to charge the reference capacitor 20, and charges the voltage of the reference capacitor 20 to the voltage of the power source V CC . Thereafter, the processing circuit 30 generates the second control signal P 2 . At this time, the processing circuit 30 stops generating and transmitting the first control signal P 1 , and the processing circuit 30 transmits the second control signal P 2 to the second switch 42 , so that the capacitor 10 to be tested shares the voltage on the reference capacitor 20 , and then processes The circuit 30 generates a third control signal P 3 . At this time, the processing circuit 30 stops generating and transmitting the second control signal P 2 , and the processing circuit 30 transmits the third control signal P 3 to the third switch 44 to turn on the third switch 44. The voltage of the capacitor 10 to be tested discharges to the ground.
Based on the above, the processing circuit 30 sequentially switches the second switch 42 and the third switch 44 several times, and gradually reduces the sensing voltage V S between the reference capacitors 20 until the sensing voltage V S is less than the threshold value V b . It can be known from the above formula (1) and formula (2) that the capacitance value when the object touches the capacitor 10 to be tested is not the same as the capacitance value when the object does not touch the capacitor 10 to be tested, and the object touches the capacitor 10 to be tested. Finally, the sense voltage V S of the difference between the threshold V b V 2 is not touched with the object to be measured capacitor 10, and finally the sense voltage V S with a difference threshold V b V 1 is not the same, so, The processing circuit 30 of this embodiment can determine whether the object touches the capacitor 10 to be tested by the difference between the last sense voltage V S and the threshold value V b . As shown in the third figure, the solid line indicates that the object is not touched. The signal of the capacitor 10 is touched, and the broken line indicates the signal that the object touches the capacitor 10 to be tested. Therefore, when the object touches the capacitor 10 to be tested, the difference V 2 between the final sense voltage V S and the threshold value V b It will be greater than the difference V 1 between the last sense voltage V S and the threshold value V b when the object does not touch the capacitor 10 to be tested, so the processing circuit 30 By comparing the difference between the sense voltage V S and the threshold value V b , it is known whether the object contacts the capacitor 10 to be tested, that is, when the difference between the previous sense voltage V S and the threshold value V b is too large, it indicates The object touches the capacitor 10 to be tested.
Referring to the second figure, the processing circuit 30 of the present invention includes an analog-to-digital conversion unit 32 and a processing unit 34. The analog digital conversion unit 32 has a first input end and a second input end. The first input end is coupled to the receiving capacitance 10 and the reference capacitor 20, and receives the sensing voltage V S , and the second input receives the threshold value V b . The analog digital conversion unit 32 generates a digital data based on the sensing voltage V S and the threshold value V b . The processing unit 34 is coupled to the analog digital conversion unit 32, and controls the level of the sensing voltage V S according to the digital data to determine that the object contacts the capacitor 10 to be tested, that is, the digital data can be equivalent to the sensing voltage V S and the threshold value V b . The difference value is so that the processing unit 34 can know the difference between the sensing voltage V S and the threshold value V b through the digital data, and whether the object contacts the capacitor 10 to be tested by the difference of the front and back digital data.
In addition, the capacitance measuring circuit 1 of the present invention further includes a differential amplifier 36. The differential amplifier 36 has a first input end, a second input end and two output ends. The first input end of the differential amplifier 36 is coupled to the reference capacitor 20 and the capacitor 10 to be tested to receive the sensing signal V S , and the differential amplifier 36 The second input receives the threshold value V b , and the differential amplifier 36 amplifies the difference between the sensing signal V S and the threshold value V b , and transmits the difference to the analog digital conversion unit 32 via the output of the differential amplifier 36 . To convert.
Based on the above, the capacitance measuring circuit 1 of the present invention uses the difference V 2 between the sensing voltage V S and the threshold value V b when the object touches the capacitor 10 to be tested, and when the object does not touch the capacitor 10 to be tested, sense voltage V S and the difference between the threshold V b V 1 is determined whether the object to be measured touches the capacitor 10, which does not touch the object to be measured capacitor 10, the sense voltage V S and the difference between the threshold V b The formula for V 1 is as follows:
V 1 =V b -V S
= V b - (Vcc-K*Cb)----------(3)
Where K is a multiple of the amplified signal of the differential amplifier 36, and when the object touches the capacitor 10 to be tested, the formula of the difference V 2 between the sensed voltage V S and the threshold value V b is as follows:
V 2 = V b -V S
= V b - (Vcc-K*(Cb+Cf))----------(4)
Above sense voltage V S with the threshold value V b is the difference between V 1 converts the sense voltage V S with the threshold value V b of the difference V 2 via the analog to digital converter 32 into digital data, i.e. analog to digital converter 32 Converting the difference V 1 and the difference V 2 into digital data can be expressed as follows:
Qadc1=quant(V 1 )-------------------(5)
Qadc2=quant(V 2 )-------------------(6)
The processing circuit 30 of the present invention can use the difference between the values of Qadc1 and Qadc2 to determine whether the capacitor 10 to be tested is touched by an object, which can be expressed as follows:
Qadc2-Qadc1=quant(V2)-quant(V1)
=quant(K*Cf)---------(7)
It can be seen from the formula (7) that the capacitance measuring circuit 1 of the present invention can measure whether the object touches the capacitor 10 to be tested by ignoring the Cb factor of the background capacitance, and can effectively and accurately measure the capacitance of the object to the ground. The value Cf is used for the purpose of increasing the accuracy of the measurement.
In addition, the capacitance measuring circuit 1 of the present invention can sequentially switch the second switch 42 and the third switch 44 several times by using the processing circuit 30, and gradually reduce the sensing voltage V S between the reference capacitors 20 until sensing. The voltage V S is less than the threshold value V b , and it is known whether the object touches the capacitor 10 to be tested. Otherwise, please refer to the fourth figure, which is a circuit diagram of another embodiment of the capacitance measuring circuit of the present invention. As shown in the figure, the difference between the capacitance measuring circuit 5 of the present embodiment and the embodiment of the second embodiment is a capacitor 50 to be tested, a reference capacitor 60 and a third switch of the capacitance measuring circuit 5 of this embodiment. 74 is coupled to the power supply terminal Vcc, and the first switch 70 of the embodiment is coupled to the ground. The measurement method of this embodiment is as shown in FIG. 5, and the initial voltage of the reference capacitor 60 is first adjusted to zero. And the charge on the capacitor 50 to be tested is shared by the reference capacitor 60. The processing circuit 80 can use a first switch 70, a second switch 72 and a third switch 74 to charge the voltage V S on the reference capacitor 60 from zero to After being greater than the threshold value V b , it is determined whether the object touches the capacitor 50 to be tested according to the difference between the front and rear voltages V S and the threshold value V b , wherein the processing circuit 80 determines the front and rear voltages V S and the threshold value V b . The manner of the difference between the technical field and the general knowledge can be easily imagined according to the above formula, and thus will not be described again.
In summary, the capacitance measuring circuit of the present invention is coupled to a capacitor to be tested and a reference capacitor by a processing circuit, and senses a voltage and a threshold according to a capacitance to be measured and a reference capacitor. When the voltage is measured, the sense voltage is less than the threshold value, and the object is contacted with the capacitor to be tested according to the difference between the sense voltage and the threshold value. Thus, the present invention can save the circuit area and achieve the purpose of saving by the circuit structure circuit of the processing circuit.
The invention is a novelty, progressive and available for industrial use, and should meet the requirements of the patent application stipulated in the Patent Law of China, and the invention patent application is filed according to law, and the prayer bureau will grant the patent as soon as possible. prayer.
However, the above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and the shapes, structures, features, and spirits described in the claims are equivalently changed. Modifications are intended to be included in the scope of the patent application of the present invention.
1．．．電容量測電路1. . . Capacitance measuring circuit
10．．．待測電容10. . . Capacitance to be tested
12．．．焊墊12. . . Solder pad
20．．．參考電容20. . . Reference capacitor
22．．．焊墊twenty two. . . Solder pad
30．．．處理電路30. . . Processing circuit
32．．．類比數位轉換單元32. . . Analog digital conversion unit
34．．．處理單元34. . . Processing unit
36．．．差分放大器36. . . Differential amplifier
40．．．第一開關40. . . First switch
42．．．第二開關42. . . Second switch
44．．．第三開關44. . . Third switch
5．．．電容量測電路5. . . Capacitance measuring circuit
50．．．待測電容50. . . Capacitance to be tested
60．．．參考電容60. . . Reference capacitor
70．．．第一開關70. . . First switch
72．．．第二開關72. . . Second switch
74．．．第三開關74. . . Third switch
80．．．處理電路80. . . Processing circuit
第一A圖係為本發明之電容量測電路之一實施例的示意圖；
第一B圖係為本發明之電容量測電路之另一實施例的示意圖；
第二圖係為本發明之電容量測電路的一實施例的電路圖；
第三圖係為本發明之電容量測電路的一實施例的波形圖；
第四圖係為本發明之電容量測電路之另一實施例的電路圖；以及
第五圖係為本發明之電容量測電路之另一實施例的波形圖。
The first A diagram is a schematic diagram of an embodiment of the capacitance measuring circuit of the present invention;
The first B diagram is a schematic diagram of another embodiment of the capacitance measuring circuit of the present invention;
The second drawing is a circuit diagram of an embodiment of the capacitance measuring circuit of the present invention;
The third figure is a waveform diagram of an embodiment of the capacitance measuring circuit of the present invention;
The fourth drawing is a circuit diagram of another embodiment of the capacitance measuring circuit of the present invention; and the fifth drawing is a waveform diagram of another embodiment of the capacitance measuring circuit of the present invention.
1．．．電容量測電路1. . . Capacitance measuring circuit
10．．．待測電容10. . . Capacitance to be tested
12．．．焊墊12. . . Solder pad
20．．．參考電容20. . . Reference capacitor
22．．．焊墊twenty two. . . Solder pad
30．．．處理電路30. . . Processing circuit
32．．．類比數位轉換單元32. . . Analog digital conversion unit
34．．．處理單元34. . . Processing unit
36．．．差分放大器36. . . Differential amplifier
40．．．第一開關40. . . First switch
42．．．第二開關42. . . Second switch
44．．．第三開關44. . . Third switch
Claims (10)
一待測電容，耦接一焊墊，並用以量測一物件觸碰該待測電容，而產生一感測電壓；
一參考電容，耦接該待測電容；以及
一處理電路，耦接該待測電容與該參考電容，並依據該感測電壓與一門檻值，調整該感測電壓之位準，當該感測電壓小於該門檻值，並依據該感測電壓與該門檻值的差異判斷該物件是否觸碰該待測電容。A capacitance measuring circuit comprising:
a capacitor to be tested is coupled to a pad and used to measure an object to touch the capacitor to be tested to generate a sensing voltage;
a reference capacitor coupled to the capacitor to be tested; and a processing circuit coupled to the capacitor to be tested and the reference capacitor, and adjusting the level of the sensing voltage according to the sensing voltage and a threshold value, when the sense The measured voltage is less than the threshold value, and determining whether the object touches the capacitance to be tested according to the difference between the sensing voltage and the threshold value.
一開關，耦接於一電源與該參考電容之間，並受控於該處理電路，當該開關導通，該電源對該參考電容進行充電。For example, the capacitance measuring circuit described in claim 1 further includes:
A switch is coupled between a power source and the reference capacitor and controlled by the processing circuit. When the switch is turned on, the power source charges the reference capacitor.
一第一開關，耦接於該待測電容與該參考電容之間，並受控於該處理電路；以及
一第二開關，耦接耦接該待測電容與一接地端之間，並受控於該處理電路；
其中，該處理電路依序控制該第一開關與該第二開關導通，而調整該感測電壓的位準。For example, the capacitance measuring circuit described in claim 1 further includes:
a first switch coupled between the capacitor to be tested and the reference capacitor and controlled by the processing circuit; and a second switch coupled to the capacitor to be tested and a ground terminal Controlled by the processing circuit;
The processing circuit sequentially controls the first switch and the second switch to be turned on, and adjusts the level of the sensing voltage.
一類比數位轉換單元，具有一第一輸入端與一第二輸入端，該第一輸入端耦接該待測電容與該參考電容(這段怪怪的, 待測電容與該參考電容並沒直接接在一起 )，並接收該感測電壓，該第二輸入端接收該門檻值，該類比數位轉換單元依據該感測電壓與該門檻值的差值產生一數位資料；以及
一處理單元，耦接該類比數位轉換單元，並依據該數位資料控制該感測電壓的準位與判斷該物件是否觸碰該待測電容。The capacitance measuring circuit of claim 1, wherein the processing circuit comprises:
An analog-to-digital conversion unit has a first input end and a second input end, the first input end is coupled to the capacitor to be tested and the reference capacitor (this strange, the capacitance to be tested and the reference capacitor are not Directly connected together, and receiving the sensing voltage, the second input terminal receives the threshold value, the analog digital conversion unit generates a digital data according to the difference between the sensing voltage and the threshold value; and a processing unit, The analog digital conversion unit is coupled, and controls the level of the sensing voltage according to the digital data and determines whether the object touches the capacitance to be tested.
一差分放大器，具有一第一輸入端,第二輸入端與二輸出端，該第一輸入端耦接該參考電容而接收該待測電壓，該第二輸入端接收一門檻值，該差分放大器用以放大該感測電壓與該門檻值之一差值，並經由該二輸出端傳送該差值至類比數位轉換單元。The capacitance measuring circuit of claim 6, wherein the processing circuit further comprises:
a differential amplifier having a first input terminal, a second input terminal and a second output terminal, the first input terminal coupled to the reference capacitor to receive the voltage to be tested, and the second input terminal receiving a threshold value, the differential amplifier And amplifying the difference between the sensing voltage and the threshold value, and transmitting the difference to the analog digital conversion unit via the two outputs.
一待測電容，耦接一焊墊，並用以量測一物件觸碰該待測電容；
一參考電容，耦接該待測電容；以及
一處理電路，耦接該待測電容與該參考電容，並依據該感測電壓與一門檻值，調整該感測電壓之位準，當該感測電壓大於該門檻值，並依據該感測電壓與該門檻值的差異判斷該物件觸碰該待測電容。A capacitance measuring circuit comprising:
a capacitor to be tested, coupled to a pad, and used to measure an object to touch the capacitor to be tested;
a reference capacitor coupled to the capacitor to be tested; and a processing circuit coupled to the capacitor to be tested and the reference capacitor, and adjusting the level of the sensing voltage according to the sensing voltage and a threshold value, when the sense The measured voltage is greater than the threshold value, and the object is touched to the capacitance to be tested according to the difference between the sensing voltage and the threshold value.
一開關，耦接於一接地端與該參考電容之間，並受控於該處理電路，當該開關導通，該參考電容對該接地端進行放電。For example, the capacitance measuring circuit described in claim 8 of the patent scope further includes:
A switch is coupled between a ground terminal and the reference capacitor and controlled by the processing circuit. When the switch is turned on, the reference capacitor discharges the ground.
一第一開關，耦接於該待測電容與該參考電容之間，並受控於該處理電路；以及
一第二開關，耦接耦接該待測電容與一電源之間，並受控於該處理電路；
其中，該處理電路依序控制該第一開關與該第二開關導通，而調整該感測電壓的位準。For example, the capacitance measuring circuit described in claim 8 of the patent scope further includes:
a first switch coupled between the capacitor to be tested and the reference capacitor and controlled by the processing circuit; and a second switch coupled to the capacitor to be tested and a power source and controlled In the processing circuit;
The processing circuit sequentially controls the first switch and the second switch to be turned on, and adjusts the level of the sensing voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| TW100136835A TW201315970A (en) | 2011-10-11 | 2011-10-11 | Capacity measuring circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| TW100136835A TW201315970A (en) | 2011-10-11 | 2011-10-11 | Capacity measuring circuit |
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| Publication Number | Publication Date |
|---|---|
| TW201315970A true TW201315970A (en) | 2013-04-16 |
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| TW100136835A TW201315970A (en) | 2011-10-11 | 2011-10-11 | Capacity measuring circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111382829A (en) * | 2018-12-27 | 2020-07-07 | 拉碧斯半导体株式会社 | IC tag and method for manufacturing IC tag |
-
2011
- 2011-10-11 TW TW100136835A patent/TW201315970A/en unknown
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111382829A (en) * | 2018-12-27 | 2020-07-07 | 拉碧斯半导体株式会社 | IC tag and method for manufacturing IC tag |
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