CN106990296A - A kind of capacitive detection circuit - Google Patents
A kind of capacitive detection circuit Download PDFInfo
- Publication number
- CN106990296A CN106990296A CN201710314897.9A CN201710314897A CN106990296A CN 106990296 A CN106990296 A CN 106990296A CN 201710314897 A CN201710314897 A CN 201710314897A CN 106990296 A CN106990296 A CN 106990296A
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- Prior art keywords
- switch
- counter
- data processing
- electric capacity
- comparator
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- 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
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measurement Of Resistance Or Impedance (AREA)
Abstract
The invention provides a kind of capacitive detection circuit, belong to semiconductor integrated circuit technical field.The circuit includes：Detect electric capacity, reference capacitance, first switch, second switch and the 3rd switch, comparator, oscillator, counter and data processing unit；First switch one terminates input voltage, one end of another termination reference capacitance and one end of second switch, while being also coupled to the positive input terminal of comparator；The other end ground connection of reference capacitance；One end and one end of the 3rd switch of another termination detection electric capacity of second switch；Detect the other end ground connection of electric capacity；The other end of 3rd switch is also grounded；The negative input of comparator terminates half input voltage, the Enable Pin of the output termination counter of comparator；The input of counter connects the output of oscillator, and the output access data processing module of counter carries out data processing.Compared to traditional capacitive detection circuit, circuit of the invention has accuracy of detection high, and the advantages of strong antijamming capability.
Description
Technical field
The invention belongs to semiconductor integrated circuit technical field, and in particular to a kind of capacitive detection circuit.
Background technology
The life that the capacitive touch technology of current fast development gives people brings many facilities, and touch key-press is wide
The general every aspect for being applied to the lives such as desk lamp, refrigerator, so judging whether to touch by detecting the size of capacitance
Capacitive detection circuit just become more and more important.
Traditional capacitance measurement technique is all by the way that electric capacity is placed in RC oscillators, by detecting RC oscillator frequencies
Change to judge the change of capacitance.
This traditional detection method is low to the accuracy of detection of electric capacity, and antijamming capability is weak.
The content of the invention
To solve the existing technical problem that capacitive detection circuit accuracy of detection is low, antijamming capability is weak, the invention provides
A kind of accuracy of detection is high, the capacitive detection circuit of strong antijamming capability.
A kind of capacitive detection circuit, including：Detect electric capacity CX, reference capacitance CR, first switch S1, second switch S2 and
Three switch S3, comparator COMP, oscillator OSC, counter Counter and data processing unit Data processing；The
The one switch termination input voltages of S1 mono- VREF, another termination reference capacitance CROne end and second switch S2 one end, while also connecing
To the positive input terminal of comparator；Reference capacitance CRThe other end ground connection；Second switch S2 another termination detection electric capacity CXOne end
With the 3rd switch S3 one end；Detect electric capacity CXThe other end ground connection；The 3rd switch S3 other end is also grounded；Comparator COMP
Negative input terminate half input voltage 1/2VREF, comparator COMP output termination counter Counter Enable Pin EN；Count
Device Counter input connects oscillator OSC output, counter Counter output access data processing module Date
Processing carries out data processing.
The capacitive detection circuit of the present invention, first first switch S1 is opened, by reference capacitance CRVoltage be charged to input electricity
Press VREF, then the switches of second switch S2 and the 3rd S3 is alternately opened again, such reference capacitance CROn voltage will gradually under
Drop, as reference capacitance CROn voltage drop to 1/2VREFAfterwards, comparator COMP is overturn, and at this time rolling counters forward terminates.Institute
So that the size of count value is just with detecting electric capacity CXOne-to-one relation is formed, the change of count value also just embodies detection electricity
Hold CXChange, so as to form with compared with high measurement accuracy, and the capacitive detection circuit with stronger antijamming capability.
Brief description of the drawings
Fig. 1 is the capacitive detection circuit structural representation that first embodiment of the invention is provided.
Embodiment
To make the object, technical solutions and advantages of the present invention of greater clarity, with reference to embodiment and join
According to accompanying drawing, the present invention is described in more detail.It should be understood that these descriptions are merely illustrative, and it is not intended to limit this hair
Bright scope.In addition, in the following description, the description to known features and technology is eliminated, to avoid unnecessarily obscuring this
The concept of invention.
Traditional capacitance measurement technique is by the way that electric capacity is placed in RC oscillators, by detecting RC oscillator frequencies
Change judges the change of capacitance, so as to cause that the accuracy of detection to electric capacity is low, antijamming capability is weak.
The accuracy of detection and antijamming capability of capacitance measurement technique are how improved, is those skilled in the art's technology urgently to be resolved hurrily
Problem.
By many-side research, the present invention overturn traditional capacitance measurement technique there is provided a kind of new accuracy of detection it is high,
The capacitive detection circuit of strong antijamming capability, as shown in figure 1, the capacitive detection circuit includes：Detect electric capacity CX, reference capacitance CR、
First switch S1, second switch S2 and the 3rd switch S3, comparator COMP, oscillator OSC, counter Counter and data
Processing unit Data processing；The termination input voltages of first switch S1 mono- VREF, another termination reference capacitance CROne end
With second switch S2 one end, while being also coupled to the positive input terminal of comparator；Reference capacitance CRThe other end ground connection；Second switch
S2 another termination detection electric capacity CXOne end and the 3rd switch S3 one end；Detect electric capacity CXThe other end ground connection；3rd switch
The S3 other end is also grounded；Comparator COMP negative input terminates half input voltage 1/2VREF, comparator COMP output termination
Counter Counter Enable Pin EN；Counter Counter input connects oscillator OSC output, counter Counter's
Output access data processing module Date processing carry out data processing.
The capacitive detection circuit of the present invention, first first switch S1 is opened, by reference capacitance CRVoltage be charged to input electricity
Press VREF, then the switches of second switch S2 and the 3rd S3 is alternately opened again, such reference capacitance CROn voltage will gradually under
Drop, as reference capacitance CROn voltage drop to 1/2VREFAfterwards, comparator COMP is overturn, and at this time rolling counters forward terminates.Institute
So that the size of count value is just with detecting electric capacity CXOne-to-one relation is formed, the change of count value also just embodies detection electricity
Hold CXChange, so as to form with compared with high measurement accuracy, and the capacitive detection circuit with stronger antijamming capability.
In the present invention, half input voltage 1/2VREFFor input voltage VREFThe half size of value.
It should be appreciated that the above-mentioned embodiment of the present invention is used only for exemplary illustration or explains the present invention's
Principle, without being construed as limiting the invention.Therefore, that is done without departing from the spirit and scope of the present invention is any
Modification, equivalent substitution, improvement etc., should be included in the scope of the protection.In addition, appended claims purport of the present invention
Covering the whole changes fallen into scope and border or this scope and the equivalents on border and repairing
Change example.
Claims (1)
1. a kind of capacitive detection circuit, it is characterised in that including：Detect electric capacity CX, reference capacitance CR, first switch S1, second open
Close the switches of S2 and the 3rd S3, comparator COMP, oscillator OSC, counter Counter and data processing unit Data
processing；The termination input voltages of first switch S1 mono- VREF, another termination reference capacitance CROne end and second switch S2
One end, while being also coupled to the positive input terminal of comparator；Reference capacitance CRThe other end ground connection；Second switch S2 another termination inspection
Survey electric capacity CXOne end and the 3rd switch S3 one end；Detect electric capacity CXThe other end ground connection；The 3rd switch S3 other end also connects
Ground；Comparator COMP negative input terminates half input voltage 1/2VREF, comparator COMP output termination counter Counter's
Enable Pin EN；Counter Counter input connects oscillator OSC output, counter Counter output access data processing
Module Date processing carry out data processing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710314897.9A CN106990296A (en) | 2017-05-07 | 2017-05-07 | A kind of capacitive detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710314897.9A CN106990296A (en) | 2017-05-07 | 2017-05-07 | A kind of capacitive detection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN106990296A true CN106990296A (en) | 2017-07-28 |
Family
ID=59417461
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710314897.9A Pending CN106990296A (en) | 2017-05-07 | 2017-05-07 | A kind of capacitive detection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN106990296A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2020014977A1 (en) * | 2018-07-20 | 2020-01-23 | 深圳市汇顶科技股份有限公司 | Capacitance detection circuit, touch detection apparatus and terminal device |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN86101617A (en) * | 1985-06-11 | 1987-01-21 | 约翰·弗兰克制造公司 | Measure the method and the instrument of electric capacity |
| JPH07318365A (en) * | 1994-05-26 | 1995-12-08 | Fuji Koki Seisakusho:Kk | Electrostatic-capacity converter |
| JP2002530680A (en) * | 1998-11-20 | 2002-09-17 | フィリップ・ハラルド | Charge transfer capacitance measurement circuit |
| CN1677115A (en) * | 2004-03-30 | 2005-10-05 | 爱信精机株式会社 | Capacitance change detection device |
| CN1766660A (en) * | 2004-09-08 | 2006-05-03 | 欧姆龙株式会社 | Capacitance measuring arrangement, method, and program |
| CN203117298U (en) * | 2013-01-30 | 2013-08-07 | 比亚迪股份有限公司 | Capacitance detection circuit |
| CN105652099A (en) * | 2016-02-22 | 2016-06-08 | 西安电子科技大学 | Micro capacitance difference detection method based on switching circuit |
-
2017
- 2017-05-07 CN CN201710314897.9A patent/CN106990296A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN86101617A (en) * | 1985-06-11 | 1987-01-21 | 约翰·弗兰克制造公司 | Measure the method and the instrument of electric capacity |
| JPH07318365A (en) * | 1994-05-26 | 1995-12-08 | Fuji Koki Seisakusho:Kk | Electrostatic-capacity converter |
| JP2002530680A (en) * | 1998-11-20 | 2002-09-17 | フィリップ・ハラルド | Charge transfer capacitance measurement circuit |
| CN1677115A (en) * | 2004-03-30 | 2005-10-05 | 爱信精机株式会社 | Capacitance change detection device |
| CN1766660A (en) * | 2004-09-08 | 2006-05-03 | 欧姆龙株式会社 | Capacitance measuring arrangement, method, and program |
| CN203117298U (en) * | 2013-01-30 | 2013-08-07 | 比亚迪股份有限公司 | Capacitance detection circuit |
| CN105652099A (en) * | 2016-02-22 | 2016-06-08 | 西安电子科技大学 | Micro capacitance difference detection method based on switching circuit |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2020014977A1 (en) * | 2018-07-20 | 2020-01-23 | 深圳市汇顶科技股份有限公司 | Capacitance detection circuit, touch detection apparatus and terminal device |
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| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20170728 |