CN108365825A - Digital tunable capacitor circuit - Google Patents
Digital tunable capacitor circuit Download PDFInfo
- Publication number
- CN108365825A CN108365825A CN201810465951.4A CN201810465951A CN108365825A CN 108365825 A CN108365825 A CN 108365825A CN 201810465951 A CN201810465951 A CN 201810465951A CN 108365825 A CN108365825 A CN 108365825A
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- Prior art keywords
- operational amplifier
- capacitance
- resistance
- circuit
- resistor
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- 239000003990 capacitor Substances 0.000 title claims abstract description 11
- 230000003321 amplification Effects 0.000 claims abstract description 8
- 238000003199 nucleic acid amplification method Methods 0.000 claims abstract description 8
- 230000005611 electricity Effects 0.000 claims description 5
- 241000208340 Araliaceae Species 0.000 claims 1
- 235000005035 Panax pseudoginseng ssp. pseudoginseng Nutrition 0.000 claims 1
- 235000003140 Panax quinquefolius Nutrition 0.000 claims 1
- 235000008434 ginseng Nutrition 0.000 claims 1
- 230000001105 regulatory effect Effects 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 5
- 230000002238 attenuated effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
- H03F1/38—Positive-feedback circuit arrangements without negative feedback
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Networks Using Active Elements (AREA)
Abstract
The present invention relates to a kind of digital tunable capacitor circuits, including the first operational amplifier, the first capacitance and gain module；The reverse input end connection first resistor and second resistance of first operational amplifier；The first resistor and second resistance forms reverse amplification circuit with the first operational amplifier；One end of first capacitance connects the reverse input end of the first operational amplifier；The gain module is connected between the output end of the first operational amplifier and the other end of the first capacitance.The present invention can carry out practical equivalent capacity of the capacitance on circuit by digital analog converter DAC digital regulated, frequency response adjusting can be carried out to most active filters, need different switches and capacitance to carry out a turn parallel connection like that rather than traditional circuit and adjust like that；Circuit, and adjustable range and resolution ratio higher can not only be simplified, the active filter circuit for the overwhelming majority is all applicable.
Description
Technical field
The present invention relates to electronic measuring technology field, especially a kind of digital tunable capacitor circuit.
Background technology
Many circuits need different capacitances to be adjusted different frequency responses, under most of the cases are connected by analog switch
Multiple capacitances are connect, by the control to analog switch, realize the connection in series-parallel between capacitance, the capacitance to be needed.In this way
Circuit can only generally adjust limited capacitance, and the capacitance majority adjusted is all to determine in a certain range.
Invention content
The technical problem to be solved by the present invention is to：A kind of digital tunable capacitor circuit is provided, can be solved to multi-frequency
Signal is filtered, and reduces switch and capacitance quantity.
The technical solution adopted by the present invention to solve the technical problems is：A kind of number tunable capacitor circuit, including first
Operational amplifier, the first capacitance and gain module；First operational amplifier reverse input end connection first resistor and
Second resistance；The first resistor and second resistance forms reverse amplification circuit with the first operational amplifier；Described first
One end of capacitance connects the reverse input end of the first operational amplifier；The gain module is connected to the first operational amplifier
Between output end and the other end of the first capacitance.
Further, gain module of the present invention includes second operational amplifier and digital analog converter；Institute
The reference voltage input terminal of the noninverting input connection digital analog converter for the second operational amplifier stated；Second operation amplifier
The reverse input end of device connects the 5th resistance and the 6th resistance；The first electricity of output end connection of the second operational amplifier
Hold；The output end connection 3rd resistor of the digital simulator and the 4th resistance；The 3rd resistor is put with the first operation
The output end of big device is connected；4th resistance eutral grounding.
It further says, the power end input voltage of digital analog converter of the present invention is+3.3V, ground terminal
Input voltage is -1.4V.
It further says, the 5th resistance, the 6th resistance and second operational amplifier of the present invention are to third electricity
Resistance and the decaying of the 4th resistance carry out equal proportion amplification.
The invention has the advantages that solving defect present in background technology, digital analog converter can be passed through
DAC is digital regulated to practical equivalent capacity progress of the capacitance on circuit, can carry out frequency response to most active filters
It adjusts, needs different switches and capacitance to carry out a turn parallel connection like that rather than traditional circuit and adjust like that；Electricity can not only be simplified
Road, and adjustable range and resolution ratio higher, the active filter circuit for the overwhelming majority is all applicable.
Description of the drawings
Present invention will be further explained below with reference to the attached drawings and examples.
Fig. 1 is the circuit diagram of basic circuit one；
Fig. 2 is the circuit diagram of basic circuit two；
Fig. 3 is the circuit diagram of the present invention.
Specific implementation mode
Presently in connection with attached drawing and preferred embodiment, the present invention is described in further detail.These attached drawings are simplified
Schematic diagram, the basic structure of the invention will be illustrated schematically only, therefore it only shows the composition relevant to the invention.
Basic circuit one as shown in Figure 1, can derive formula 1：
Basic circuit two as shown in Figure 2 derives：
V2=GAIN × VO
So：
So formula 2 can be obtained
It is compared by formula 1 and formula 2, it can be found that：The equivalent capacity C=C1 of formula 1, the equivalent capacity C=of formula 2
C1·GAIN。
As soon as because a gain module is increased in C1 and amplifier output end, so equivalent capacity changes, it is believed that
Gain module adjusts capacitance C1.
If gain G AIN>1, then it is that adjusting is amplified to capacitance, if GAIN<1, this capacitance carries out Attenuation adjustable.
If
It can be seen that it the sections such as is to carry out capacitance adjustment.Because the truth of a matter is 2NIt is constant, and D is sections can be waited increased.
If
It can be found that denominator is to change, molecule is constant, and such adjusting is not just linear.So of the invention
It is mainly used forIn the state of adjusting.
Physical circuit is as shown in figure 3, R1, R2, R3, R4, R5, R6 are resistance；C1 is capacitance；U1, U3 are amplifiers；U2 is
DAC；R1, R2 and U1 form basic reverse amplification circuit；U2 is the adjusting DAC to C1, and the electricity of C1 is mainly flowed through by adjusting
Hold to adjust actual equivalent capacity；U3 is to carry out equal proportion amplification to decay to prime；
Supply voltage on amplifier U1 and U3 is VCC and VEE, and general VCC gives+15V, VEE to give -15V；
Voltage on U2 is to -1.4V and+3.3V, because of AC signal when input signal, relatively have it is positive and negative, if
Lower terminal voltage is not less than 0, then negative terminal signal cannot have adjusted, so the low side of power supply needs a negative voltage, as long as ensureing
Voltage difference can in the supply district of DAC.
R3 and R4 be in order among being input to DAC again in attenuated output signal to the manageable ranges of DAC, just in this way
Signal can normally be handled.
R5 and R6 and U3 is that the decaying to R3 and R4 carries out equal proportion amplification.
Input signal Vi, output signal Vo, derives according to schematic diagram：
D is enter into the data of DAC, and data area is 0~2N-1；N is the digit of DAC
So
Make：
R4=R5, R3=R6
So
Because：
So：
So：
This, which can be seen that, comes, and actual capacitance have passed throughDecaying.So the circuit is 0 to arrive to the adjusting of capacitance
The frame of entire circuit is input signal, output signal, power supply, adjusts capacitance and adjust DAC used.It is logical
DAC is overregulated to adjust the size for the electric current for flowing through capacitance, to adjust output end and capacitance in the equivalent of the connecting pin of amplifier
Capacitance size, to adjust the frequency response of entire circuit.
The present invention can use on active analog filter circuit, in nowadays industrial circle to the filter circuit of signal with
Locate visible.It is required for being filtered signal in many electronic metering equipments.So the circuit can use in big portion
Among the industrial equipment divided.Especially among the wider adjusting circuit of frequency range.Also some volumetric constraints still need
The principle can also be used in prodigious capacitor filter carries out ratio enlargement to capacitance.
The specific implementation mode of the only present invention described in description above, various illustrations are not to the reality of the present invention
Matter Composition of contents limits, and person of an ordinary skill in the technical field can be to described in the past specific after having read specification
Embodiment is made an amendment or is deformed, without departing from the spirit and scope of invention.
Claims (4)
1. a kind of number tunable capacitor circuit, it is characterised in that：Including the first operational amplifier, the first capacitance and gain module；
The reverse input end connection first resistor and second resistance of first operational amplifier；The first resistor and the second electricity
Resistance forms reverse amplification circuit with the first operational amplifier；One end of first capacitance connects the anti-of the first operational amplifier
To input terminal；The gain module is connected between the output end of the first operational amplifier and the other end of the first capacitance.
2. number tunable capacitor circuit as described in claim 1, it is characterised in that：The gain module includes the second operation
Amplifier and digital analog converter；The ginseng of the noninverting input connection digital analog converter of the second operational amplifier
Examine voltage input end；The reverse input end of second operational amplifier connects the 5th resistance and the 6th resistance；Second operation
The output end of amplifier connects the first capacitance；The output end connection 3rd resistor of the digital simulator and the 4th resistance；Institute
The 3rd resistor stated is connected with the output end of the first operational amplifier；4th resistance eutral grounding.
3. number tunable capacitor circuit as claimed in claim 2, it is characterised in that：The power supply of the digital analog converter
End input voltage is+3.3V, and ground terminal input voltage is -1.4V.
4. number tunable capacitor circuit as claimed in claim 2, it is characterised in that：5th resistance, the 6th resistance with
And second operational amplifier carries out equal proportion amplification to the decaying of 3rd resistor and the 4th resistance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810465951.4A CN108365825A (en) | 2018-05-16 | 2018-05-16 | Digital tunable capacitor circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810465951.4A CN108365825A (en) | 2018-05-16 | 2018-05-16 | Digital tunable capacitor circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN108365825A true CN108365825A (en) | 2018-08-03 |
Family
ID=63012323
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810465951.4A Pending CN108365825A (en) | 2018-05-16 | 2018-05-16 | Digital tunable capacitor circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108365825A (en) |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU944076A1 (en) * | 1980-02-22 | 1982-07-15 | Ленинградский Ордена Ленина Политехнический Институт Им.М.И.Калинина | Bandpass active rc-filter |
| JP2002290208A (en) * | 2001-03-23 | 2002-10-04 | Tsuru Gakuen | Ultra-low frequency signal processing circuit |
| CN103138696A (en) * | 2011-11-29 | 2013-06-05 | 成都凯天电子股份有限公司 | Electric charge integrating amplifier |
| US20150229292A1 (en) * | 2014-02-12 | 2015-08-13 | Electronics And Telecommunications Research Institute | Second order loop filter and multi-order delta sigma modulator including the same |
| CN104954022A (en) * | 2015-07-17 | 2015-09-30 | 深圳市芯联电子科技有限公司 | Digital converter of rotary transformer and integrating circuit of digital converter |
| CN204836096U (en) * | 2015-07-08 | 2015-12-02 | 上海大学 | Piezoelectric acceleration sensor's charge amplifier |
| JP6215398B1 (en) * | 2016-06-22 | 2017-10-18 | 力晶科技股▲ふん▼有限公司 | Switched capacitor circuit and AD converter |
| CN208174644U (en) * | 2018-05-16 | 2018-11-30 | 常州同惠电子股份有限公司 | A kind of number tunable capacitor circuit |
| CN209375592U (en) * | 2019-01-24 | 2019-09-10 | 江门市川琪科技有限公司 | A kind of power amplifier circuit |
-
2018
- 2018-05-16 CN CN201810465951.4A patent/CN108365825A/en active Pending
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU944076A1 (en) * | 1980-02-22 | 1982-07-15 | Ленинградский Ордена Ленина Политехнический Институт Им.М.И.Калинина | Bandpass active rc-filter |
| JP2002290208A (en) * | 2001-03-23 | 2002-10-04 | Tsuru Gakuen | Ultra-low frequency signal processing circuit |
| CN103138696A (en) * | 2011-11-29 | 2013-06-05 | 成都凯天电子股份有限公司 | Electric charge integrating amplifier |
| US20150229292A1 (en) * | 2014-02-12 | 2015-08-13 | Electronics And Telecommunications Research Institute | Second order loop filter and multi-order delta sigma modulator including the same |
| CN204836096U (en) * | 2015-07-08 | 2015-12-02 | 上海大学 | Piezoelectric acceleration sensor's charge amplifier |
| CN104954022A (en) * | 2015-07-17 | 2015-09-30 | 深圳市芯联电子科技有限公司 | Digital converter of rotary transformer and integrating circuit of digital converter |
| JP6215398B1 (en) * | 2016-06-22 | 2017-10-18 | 力晶科技股▲ふん▼有限公司 | Switched capacitor circuit and AD converter |
| CN208174644U (en) * | 2018-05-16 | 2018-11-30 | 常州同惠电子股份有限公司 | A kind of number tunable capacitor circuit |
| CN209375592U (en) * | 2019-01-24 | 2019-09-10 | 江门市川琪科技有限公司 | A kind of power amplifier circuit |
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