CN112014648A - 一种可以检测单侧电容的电容检测方法 - Google Patents
一种可以检测单侧电容的电容检测方法 Download PDFInfo
- Publication number
- CN112014648A CN112014648A CN202010795066.XA CN202010795066A CN112014648A CN 112014648 A CN112014648 A CN 112014648A CN 202010795066 A CN202010795066 A CN 202010795066A CN 112014648 A CN112014648 A CN 112014648A
- Authority
- CN
- China
- Prior art keywords
- capacitance
- shielding layer
- sensing unit
- cback
- sensing element
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000001514 detection method Methods 0.000 title claims abstract description 34
- 238000005070 sampling Methods 0.000 claims abstract description 10
- 238000006243 chemical reaction Methods 0.000 claims description 9
- 239000003990 capacitor Substances 0.000 claims description 6
- 238000013139 quantization Methods 0.000 claims description 5
- 238000000034 method Methods 0.000 claims description 4
- 238000012935 Averaging Methods 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 7
- 239000000284 extract Substances 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
- G01R27/26—Measuring inductance or capacitance; Measuring quality factor, e.g. by using the resonance method; Measuring loss factor; Measuring dielectric constants ; Measuring impedance or related variables
- G01R27/2605—Measuring capacitance
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
- G01D5/14—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
- G01D5/24—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying capacitance
- G01D5/241—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying capacitance by relative movement of capacitor electrodes
- G01D5/2417—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying capacitance by relative movement of capacitor electrodes by varying separation
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Measurement Of Resistance Or Impedance (AREA)
Abstract
本发明公开了一种可以检测单侧电容的电容检测方法,包括步骤:(1)进行第一次检测,将传感元件以及屏蔽层在传感器芯片内短接,并采样此时的电容,为C1=Cuser+Cback;其中,Cuse为传感元件侧的电容,Cback为屏蔽层侧的电容;(2)进行第二次检测,将传感元件以及屏蔽层分别接入电容电压转换器的正负输入端,并采样此时的电容,为C2=Cuse‑Cback;其中,传感元件接入正端,屏蔽层接入负端;(3)对两次检测结果求平均,得到传感元件单侧电容Cuser=(C1+C2)/2。本发明通过不同的连接方式对电容做两次检测,并通过对两次检测结果求平均,得到传感元件单侧电容,屏蔽层一侧的干扰电容被完全消除。
Description
技术领域
本发明涉及接近检测领域,尤其涉及一种可以检测单侧电容的电容检测方法。
背景技术
传统的电容性接触传感器利用在传感元件下面的屏蔽层以提供传感的定向性并减少来自噪声的干扰。通过检测传感元件的自电容的集成电路(IC)驱动用于电容性触摸传感的屏蔽层。当检测接近时,传感IC将屏蔽层驱动到与所关联的传感元件近似相同的电压电势。但该方法很难实现屏蔽层与感应元件的电压完全相同,当两者电势有误差后,会产生误差电荷,导致电容数据出现偏差。
发明内容
发明目的:针对以上问题,本发明提出一种可以检测单侧电容的电容检测方法,通过对电容做两次检测,来提取单侧电容。
技术方案:为实现本发明的目的,本发明所采用的技术方案是:一种可以检测单侧电容的电容检测方法,包括步骤:
(1)进行第一次检测,将传感元件以及屏蔽层在传感器芯片内短接,并采样此时的电容,为C1=Cuser+Cback;其中,Cuse为传感元件侧的电容,Cback为屏蔽层侧的电容;
(2)进行第二次检测,将传感元件以及屏蔽层分别接入电容电压转换器的正负输入端,并采样此时的电容,为C2=Cuse-Cback;其中,传感元件接入正端,屏蔽层接入负端;
(3)对两次检测结果求平均,得到传感元件单侧电容Cuser=(C1+C2)/2。
进一步地,所述步骤(1)具体包括:
(1.1)将传感单元与屏蔽层短接;
(1.2)在相位PH1时,将传感单元与屏蔽层充电至Vcharge;
(1.3)在相位PH2时,将传感单元与屏蔽层上存储的电荷转移至电容电压转换器,转移电荷量为(Cuser+Cback)*Vcharge;
(1.4)通过模数转换电路进行量化,得到电容C1=Cuser+Cback。
进一步地,传感单元与屏蔽层短接时,处于等电位,Cshield不会存储或转移电荷;其中,Cshield为传感单元与屏蔽层之间的电容值。
进一步地,所述步骤(2)具体包括:
(2.1)在相位PH1时,将屏蔽层接地,并将传感单元充电至Vcharge;
(2.2)在相位PH2时,将传感单元接入电容电压转换器,电容电压转换器得到的电荷为(Cuser+Cshiled)*Vcharge;其中,Cshield为传感单元与屏蔽层之间的电容值;
(2.3)在相位PH3时,将传感单元接地,并将屏蔽层充电至-Vcharge;
(2.4)在相位PH4时,将屏蔽层接入电容电压转换器,电容电压转换器得到的电荷为(Cback+Cshiled)*(-Vcharge);
(2.5)通过两次转换,电容电压转换器上得到的总电荷为(Cuser-Cback)*Vcharge,通过模数转换电路进行量化,得到电容C2=Cuser-Cback。
进一步地,相位PH1/PH2/PH3/PH4各差90度,为非交叠时钟。
有益效果:本发明通过不同的连接方式对电容做两次检测,并通过对两次检测结果求平均,得到传感元件单侧电容,屏蔽层一侧的干扰电容被完全消除。
附图说明
图1为本发明提供的检测单方向电容值的方法;
图2为本发明提供的带屏蔽层的电容传感器等效电路图;
图3为本发明提供的检测两侧电容和的等效电路图;
图4为本发明提供的检测两侧电容差值的等效电路图;
图5为本发明提供的传感器芯片工作时序图。
具体实施方式
下面结合附图和实施例对本发明的技术方案作进一步的说明。
基于电容信号的接近检测传感器,包括电容电压转换器、模数转换电路、数字滤波器以及接近检测算法电路。
其中,电容电压转换器,用于将电容信号转化为电压信号;高精度模数转换电路ADC,用于量化电压信号;数字滤波器以及接近检测算法电路,用于将模数转换器的输出数据进行滤波降采样,并提取出有效的接近信号,判断物体与传感器的距离。
还包括固定电容补偿电容,用于补偿电容传感器上的固定电容。
其中,电容电压转换器中包括电荷放大器A。
如图1所示,本发明所述的可以检测单侧电容的电容检测方法,利用上述的接近检测传感器进行检测,该方法会对电容做两次检测,具体包括步骤:
(1)第一次检测时,将传感元件以及屏蔽层在芯片内短接,并采样此时的电容,该电容可以表示为C1=Cuser+Cback。
其中,Cuse为感应元件侧的电容大小,为目标检测信号,Cback为屏蔽层侧的电容,为检测过程中的干扰信号。
(2)第二次检测时,将传感元件以及屏蔽层分别接入电容转换器的正负输入端,其中,传感元件接入正端,屏蔽层接入负端,所得的电容值可以表示为C2=Cuse-Cback。
(3)最后,通过对两次检测结果求平均,得到传感元件单侧电容Cuser=(C1+C2)/2。
如图2所示,为带屏蔽层结构的电容传感器的等效电容图,其中,Cuser为传感单元侧CS0的电容值,为有效电容值,Cback为屏蔽层侧CS1的电容值,为干扰源,Cshield为传感单元与屏蔽层之间的电容值。
如图3所示,为进行第一次检测采样电容C1的原理图。当采样电容C1时,将传感单元CS0与屏蔽层CS1短接。在相位PH1时,将CS0/CS1充电至Vcharge。在相位为PH2时,将CS0/CS1上存储的电荷转移至电容电压转换器,转移电荷量为(Cuser+Cback)*Vcharge,最后通过ADC量化为数字数据。ADC量化后的电容C1为传感单元CS0与屏蔽层CS1两侧的电容和Cuser+Cback。
由于CS1/CS0一直处于等电位,Cshield不会存储或转移电荷,所以对最终数据无影响。
如图4所示,为进行第二次检测采样电容C2的原理图。在相位PH1时,将屏蔽层CS1接地,并将传感单元CS0充电至Vcharge,在相位PH2时,将传感单元CS0接入电容电压转换器,电容电压转换器得到的电荷为(Cuser+Cshiled)*Vcharge。在相位PH3时,将传感单元CS0接地,并将屏蔽层CS1充电至-Vcharge,在相位PH4时,将屏蔽层CS1接入电容电压转换器,电容电压转换器得到的电荷为(Cback+Cshiled)*(-Vcharge)。
因此通过两次转换,电容电压转换器上得到的电荷为(Cuser-Cback)*Vcharge,经过ADC量化后,得到的电容值为C2=Cuser-Cback。
在数字处理中,对两次采样得到的值C1/C2求平均,得到最后的输出值为(C1+C2)/2=(Cuser+Cback+Cuser-Cback)/2=Cuser。从而得到传感单元CS0单侧的电容,屏蔽层一侧的干扰电容被完全消除。
如图5所示,为采样过程中PH1/PH2/PH3/PH4的波形图。四个波形相位各差90度,为非交叠时钟。
Claims (5)
1.一种可以检测单侧电容的电容检测方法,其特征在于,包括步骤:
(1)进行第一次检测,将传感元件以及屏蔽层在传感器芯片内短接,并采样此时的电容,为C1=Cuser+Cback;其中,Cuse为传感元件侧的电容,Cback为屏蔽层侧的电容;
(2)进行第二次检测,将传感元件以及屏蔽层分别接入电容电压转换器的正负输入端,并采样此时的电容,为C2=Cuse-Cback;其中,传感元件接入正端,屏蔽层接入负端;
(3)对两次检测结果求平均,得到传感元件单侧电容Cuser=(C1+C2)/2。
2.根据权利要求1所述的可以检测单侧电容的电容检测方法,其特征在于,所述步骤(1)具体包括:
(1.1)将传感单元与屏蔽层短接;
(1.2)在相位PH1时,将传感单元与屏蔽层充电至Vcharge;
(1.3)在相位PH2时,将传感单元与屏蔽层上存储的电荷转移至电容电压转换器,转移电荷量为(Cuser+Cback)*Vcharge;
(1.4)通过模数转换电路进行量化,得到电容C1=Cuser+Cback。
3.根据权利要求2所述的可以检测单侧电容的电容检测方法,其特征在于,传感单元与屏蔽层短接时,处于等电位,Cshield不会存储或转移电荷;其中,Cshield为传感单元与屏蔽层之间的电容值。
4.根据权利要求1所述的可以检测单侧电容的电容检测方法,其特征在于,所述步骤(2)具体包括:
(2.1)在相位PH1时,将屏蔽层接地,并将传感单元充电至Vcharge;
(2.2)在相位PH2时,将传感单元接入电容电压转换器,电容电压转换器得到的电荷为(Cuser+Cshiled)*Vcharge;其中,Cshield为传感单元与屏蔽层之间的电容值;
(2.3)在相位PH3时,将传感单元接地,并将屏蔽层充电至-Vcharge;
(2.4)在相位PH4时,将屏蔽层接入电容电压转换器,电容电压转换器得到的电荷为(Cback+Cshiled)*(-Vcharge);
(2.5)通过两次转换,电容电压转换器上得到的总电荷为(Cuser-Cback)*Vcharge,通过模数转换电路进行量化,得到电容C2=Cuser-Cback。
5.根据权利要求4所述的可以检测单侧电容的电容检测方法,其特征在于,相位PH1/PH2/PH3/PH4各差90度,为非交叠时钟。
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN202010795066.XA CN112014648B (zh) | 2020-08-10 | 2020-08-10 | 一种可以检测单侧电容的电容检测方法 |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN202010795066.XA CN112014648B (zh) | 2020-08-10 | 2020-08-10 | 一种可以检测单侧电容的电容检测方法 |
Publications (2)
Publication Number | Publication Date |
---|---|
CN112014648A true CN112014648A (zh) | 2020-12-01 |
CN112014648B CN112014648B (zh) | 2023-04-28 |
Family
ID=73499262
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CN202010795066.XA Active CN112014648B (zh) | 2020-08-10 | 2020-08-10 | 一种可以检测单侧电容的电容检测方法 |
Country Status (1)
Country | Link |
---|---|
CN (1) | CN112014648B (zh) |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20050040833A1 (en) * | 2001-09-06 | 2005-02-24 | Masami Yakabe | Capacitance measuring circuit, capacitance measuring instrument, and microphone device |
CN102221646A (zh) * | 2010-03-15 | 2011-10-19 | 阿尔卑斯电气株式会社 | 电容检测装置和电容检测方法 |
US20140078096A1 (en) * | 2012-09-14 | 2014-03-20 | Stmicroelectronics Asia Pacific Pte. Ltd. | Configurable analog front-end for mutual capacitance sensing and self capacitance sensing |
US10146390B1 (en) * | 2017-07-21 | 2018-12-04 | Cypress Semiconductor Corporation | Method of combining self and mutual capacitance sensing |
CN110058087A (zh) * | 2019-05-20 | 2019-07-26 | 武汉众行聚谷科技有限公司 | 一种强抗干扰超低功耗的全差分结构微小电容检测芯片 |
CN110134281A (zh) * | 2019-05-16 | 2019-08-16 | 上海艾为电子技术股份有限公司 | 电容检测系统及方法 |
CN110856448A (zh) * | 2018-06-21 | 2020-02-28 | 深圳市汇顶科技股份有限公司 | 电容检测电路、触控装置及终端设备 |
-
2020
- 2020-08-10 CN CN202010795066.XA patent/CN112014648B/zh active Active
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20050040833A1 (en) * | 2001-09-06 | 2005-02-24 | Masami Yakabe | Capacitance measuring circuit, capacitance measuring instrument, and microphone device |
CN102221646A (zh) * | 2010-03-15 | 2011-10-19 | 阿尔卑斯电气株式会社 | 电容检测装置和电容检测方法 |
US20140078096A1 (en) * | 2012-09-14 | 2014-03-20 | Stmicroelectronics Asia Pacific Pte. Ltd. | Configurable analog front-end for mutual capacitance sensing and self capacitance sensing |
US10146390B1 (en) * | 2017-07-21 | 2018-12-04 | Cypress Semiconductor Corporation | Method of combining self and mutual capacitance sensing |
CN110856448A (zh) * | 2018-06-21 | 2020-02-28 | 深圳市汇顶科技股份有限公司 | 电容检测电路、触控装置及终端设备 |
CN110134281A (zh) * | 2019-05-16 | 2019-08-16 | 上海艾为电子技术股份有限公司 | 电容检测系统及方法 |
CN110058087A (zh) * | 2019-05-20 | 2019-07-26 | 武汉众行聚谷科技有限公司 | 一种强抗干扰超低功耗的全差分结构微小电容检测芯片 |
Non-Patent Citations (4)
Title |
---|
JINDAL, SK: "Capacitance and sensitivity calculation of double touch mode capacitive pressure sensor: theoretical modelling and simulation", 《MICROSYSTEM TECHNOLOGIES-MICRO-ANDNANOSYSTEMS-INFORMATION STORAGE AND PROCESSING SYSTEMS》 * |
KUAN, CHIN LEE.ETC: "Dual-attached SMT Capacitor Configurations for Small Form Factor and Single-ended Devices", 《2018 IEEE EPTC》 * |
王存记等: "传感器测量转换过程中的干扰及防止措施", 《中国仪器仪表》 * |
申健: "基于线路输电特性的配电网电缆绝缘在线监测研究", 《中国优秀硕士学位论文全文数据库 (工程科技Ⅱ辑)》 * |
Also Published As
Publication number | Publication date |
---|---|
CN112014648B (zh) | 2023-04-28 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US8982093B2 (en) | Capacitive touch sensing system with interference rejection | |
US4528684A (en) | Charge-coupled device output circuit | |
CN203964928U (zh) | 用于指纹识别的电容检测装置和具有其的指纹识别装置 | |
US9529030B2 (en) | Capacitance sensing circuits and methods | |
US20140146002A1 (en) | Touch Detection System of Terminal Device and Terminal Device | |
WO2021036306A1 (zh) | 电容感测装置 | |
KR102491774B1 (ko) | 터치 검출 회로, 터치 디스플레이 장치 및 터치 검출 방법 | |
EP3385881A1 (en) | Capacitive fingerprint sensor | |
CN107092407B (zh) | 感应电容测量装置 | |
CN104748770A (zh) | 用于指纹识别的电容检测装置和具有其的指纹识别装置 | |
CN111801584B (zh) | 电容检测电路、触控装置和终端设备 | |
CN103487662A (zh) | 电容检测电路 | |
CN110411483B (zh) | 新型大尺寸传感阵列的读出电路及其传感器阵列 | |
CN103532553A (zh) | 基于循环时间数字转换器的时域adc | |
CN110210349B (zh) | 指纹传感器和移动终端 | |
CN105512650A (zh) | 一种电容式指纹检测电路、传感器及设备 | |
CN111399679B (zh) | 电容检测装置 | |
CN108664955B (zh) | 指纹识别装置 | |
CN112014648B (zh) | 一种可以检测单侧电容的电容检测方法 | |
CN203535119U (zh) | 电容检测电路 | |
CN203608184U (zh) | 基于循环时间数字转换器的时域adc | |
US20230122233A1 (en) | Nano-power architecture enhancements | |
CN111414093A (zh) | 电容式触控侦测电路 | |
US20210303098A1 (en) | Capacitance detection circuit and input device | |
US10969912B2 (en) | Capacitive sensing and sampling circuit and sensing and sampling method thereof |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PB01 | Publication | ||
PB01 | Publication | ||
SE01 | Entry into force of request for substantive examination | ||
SE01 | Entry into force of request for substantive examination | ||
GR01 | Patent grant | ||
GR01 | Patent grant | ||
PE01 | Entry into force of the registration of the contract for pledge of patent right |
Denomination of invention: A capacitance detection method that can detect unilateral capacitance Granted publication date: 20230428 Pledgee: Nanjing Zidong sub branch of Bank of Nanjing Co.,Ltd. Pledgor: NANJING TIANYI HEXIN ELECTRONIC CO.,LTD. Registration number: Y2024980015513 |
|
PE01 | Entry into force of the registration of the contract for pledge of patent right |