CN109379067A - Switching circuit and signal acquiring system - Google Patents
Switching circuit and signal acquiring system Download PDFInfo
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- CN109379067A CN109379067A CN201811519922.8A CN201811519922A CN109379067A CN 109379067 A CN109379067 A CN 109379067A CN 201811519922 A CN201811519922 A CN 201811519922A CN 109379067 A CN109379067 A CN 109379067A
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- 239000004065 semiconductor Substances 0.000 claims description 6
- 230000005611 electricity Effects 0.000 claims description 4
- 238000000034 method Methods 0.000 description 9
- 238000010586 diagram Methods 0.000 description 5
- 230000008569 process Effects 0.000 description 4
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Classifications
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/08—Modifications for protecting switching circuit against overcurrent or overvoltage
- H03K17/081—Modifications for protecting switching circuit against overcurrent or overvoltage without feedback from the output circuit to the control circuit
- H03K17/08104—Modifications for protecting switching circuit against overcurrent or overvoltage without feedback from the output circuit to the control circuit in field-effect transistor switches
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
- H03K17/56—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices
- H03K17/567—Circuits characterised by the use of more than one type of semiconductor device, e.g. BIMOS, composite devices such as IGBT
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Abstract
A kind of switching circuit and signal acquiring system provided by the invention, switching circuit includes the first sub switch, second sub switch and voltage feedback circuit, the first end of first sub switch is connect as the input terminal of switching circuit with external equipment, second end is connect with the first end of the second sub switch, the second end of second sub switch as switching circuit output end and connect with the inverting input terminal of operational amplifier circuit, the non-inverting input terminal of operational amplifier circuit is connect with a power supply, the input terminal of voltage feedback circuit connects to power supply, output end is connected between the first sub switch and the second sub switch, when carrying out signal acquisition and disconnecting switching circuit, keep the voltage of non-inverting input terminal of voltage and operational amplifier circuit between the first sub switch and the second sub switch identical, so as to be eliminated by the electric leakage that the second sub switch enters the inverting input terminal of operational amplifier circuit by stream, And then the voltage for avoiding influence of leakage current operational amplifier circuit output end from exporting is to influence signal acquisition result.
Description
Technical field
The present invention relates to analog signal sampling technique fields, in particular to a kind of switching circuit and signal acquisition system
System.
Background technique
Signal acquisition is usually in integrated circuits, to be realized by switch, usual situation lower switch is imitated using field
(MOSFET) should be managed, due to various non-ideal factors, when switch mosfet disconnects, the impedance Rs of switch input terminal to output end is not
Be it is infinitely great, therefore, when between switch is output and input there are when voltage difference Vdiff, can introduce one with voltage difference Vdiff and
The relevant switch leakage current Ileak of hindrance Rs enters the input terminal of AFE.Referring to Fig. 1, Fig. 1 show it is existing
The circuit diagram of signal acquiring system.Assuming that switch input terminal voltage is Vin (t), output switching terminal, that is, AFE out-phase input terminal
Voltage is Vcia (t), and AFE non-inverting input terminal voltage is VCOM, due to the short effect of void of amplifier, Vcia (t)=VCOM, i.e. AFE
The voltage of out-phase input terminal will not change, and therefore, switch leakage current Ileak is introduced into the electricity of the out-phase input terminal of AFE
Lotus/electric current directly affects the output voltage of AFE by feedback capacity CF.When input signal is charge or electric current, Ileak
As a noise source, the signal-to-noise ratio (SNR) of input analog signal is reduced.In signal acquisition stage, noise charge Qn is introduced
Size and acquisition time T-phase close, the noise charge of introducing is
The noise voltage that this noise charge is introduced in AFE output end is Vn, out, andTherefore, leakage current is a technical problem to be solved urgently caused by being effectively reduced because of switch.
Summary of the invention
In view of this, the purpose of the present invention is to provide a kind of switching circuit and signal acquiring system, it is above-mentioned effectively to delay
Problem.
To achieve the above object, the embodiment of the present invention adopts the following technical scheme that
A kind of switching circuit, applied to the signal acquiring system including operational amplifier circuit, the switching circuit includes the first son
Switch, the second sub switch and voltage feedback circuit；
The first end of first sub switch connect as the input terminal of the switching circuit with external equipment, second end with
The first end of second sub switch connects, the second end of second sub switch as the switching circuit output end and with
The inverting input terminal of the operational amplifier circuit connects, and the non-inverting input terminal of the operational amplifier circuit is connect with a power supply, and the voltage is anti-
The input terminal of current feed circuit and power supply connection, output end are connected between first sub switch and second sub switch,
With when carrying out signal acquisition and disconnecting the switching circuit, i.e., when disconnecting the first sub switch and the second sub switch, in institute
Under the action of stating voltage feedback circuit, make the voltage and the operational amplifier circuit between first sub switch and the second sub switch
The voltage of non-inverting input terminal is identical, so as to enter the electric leakage of the inverting input terminal of the operational amplifier circuit by second sub switch
Stream is eliminated.
Optionally, in said switching circuit, the voltage feedback circuit includes third sub switch and offset generating circuit,
The first end of the third sub switch be connected to first sub switch second end and second sub switch first end it
Between, second end connect with the first end of the offset generating circuit, the second end of the offset generating circuit and the power supply connect
It connects.
Optionally, in said switching circuit, the offset generating circuit includes the first operational amplifier, first fortune
The out-phase input terminal for calculating amplifier is connect with output end, non-inverting input terminal is connect with the power supply, output end is connected to described the
Between one sub switch and the second sub switch.
Optionally, in said switching circuit, the third sub switch is electronic switch, and the control terminal of the electronic switch
It is electrically connected with the controller in the signal acquiring system, to be connected to or disconnect the third sub switch under the action of controller
First end and second end between connection.
Optionally, in said switching circuit, first sub switch and the second sub switch are respectively electronic switch, and institute
The control terminal for stating electronic switch is electrically connected with the controller in the signal acquiring system, to be connected under the action of the controller
Or the connection between the first end and second end of disconnection first sub switch, and it is connected to or disconnects second sub switch
Connection between first end and second end.
Optionally, in said switching circuit, the electronic switch is made of single metal-oxide-semiconductor, or by a PMOS
Pipe and NMOS tube parallel connection are constituted, and when the electronic switch is made of a PMOS tube and a NMOS tube parallel connection,
The control terminal of the control terminal of the PMOS tube and the NMOS tube is connect with the controller respectively, and the control terminal of the PMOS tube and should
The level of the control terminal of NMOS tube is opposite.
Optionally, in said switching circuit, the operational amplifier circuit includes second operational amplifier and first capacitor, described
First capacitor one end connect with the out-phase input terminal of the second operational amplifier after as the operational amplifier circuit input terminal with
The second end of second sub switch connects, and the output end of the other end of the first capacitor and the second operational amplifier connects
It connects, the non-inverting input terminal of the second operational amplifier is connect as the non-inverting input terminal of the operational amplifier circuit with the power supply.
The present invention also provides a kind of signal acquiring systems, including operational amplifier circuit and above-mentioned switching circuit, switching circuit
It is connect with the operational amplifier circuit.
Optionally, in above-mentioned signal acquiring system, the signal acquiring system include sensor, multiple switch circuit with
And an operational amplifier circuit, each sensor are correspondingly connected with a switching circuit respectively, and each switching circuit difference
It is connect with the operational amplifier circuit.
Optionally, in above-mentioned signal acquiring system, the sensor includes sensor devices and parasitic capacitance, and the sense
First end after optical device and parasitic capacitance in parallel is connect with power supply device, and the input terminal of the other end and the switching circuit connects
It connects.
A kind of switching circuit and signal acquiring system provided by the invention, switching circuit include the first sub switch, the second son
Switch and voltage feedback circuit, the first end of the first sub switch connect as the input terminal of switching circuit with external equipment, second
End is connect with the first end of the second sub switch, output end and and operational amplifier circuit of the second end of the second sub switch as switching circuit
Inverting input terminal connection, the non-inverting input terminal of operational amplifier circuit connect with a power supply, the input terminal of voltage feedback circuit with it is described
Power supply connection, output end are connected between the first sub switch and the second sub switch, to carry out signal acquisition and by switching circuit
When disconnection, keep the voltage of non-inverting input terminal of voltage and operational amplifier circuit between the first sub switch and the second sub switch identical, with
It eliminates the electric leakage for entering the inverting input terminal of operational amplifier circuit by the second sub switch by stream, and then avoids influence of leakage current amplifier
The voltage of circuit output end output is to influence signal acquisition result.
To enable the above objects, features and advantages of the present invention to be clearer and more comprehensible, preferred embodiment is cited below particularly.
Detailed description of the invention
In order to illustrate the technical solution of the embodiments of the present invention more clearly, below will be to needed in the embodiment attached
Figure is briefly described, it should be understood that the following drawings illustrates only section Example of the invention, therefore is not construed as pair
The restriction of the scope of the present invention, for those of ordinary skill in the art, without creative efforts, also
Other relevant attached drawings can be obtained according to these attached drawings.
Fig. 1 is the circuit diagram of existing signal acquiring system.
Fig. 2 is a kind of circuit diagram of signal acquiring system provided in an embodiment of the present invention.
Fig. 3 is a kind of another circuit diagram of signal acquiring system provided in an embodiment of the present invention.
Fig. 4 is a kind of another circuit diagram of signal acquiring system provided in an embodiment of the present invention.
Icon: 10- signal acquiring system；100- switching circuit；110- voltage feedback circuit；The first operational amplifier of A1-；
The first sub switch of Q1-；The second sub switch of Q2-；Q3- third sub switch；C1- first capacitor；200- operational amplifier circuit；A2- second is transported
Calculate amplifier；300- sensor；D- sensor devices；C2- parasitic capacitance.
Specific embodiment
In order to make the object, technical scheme and advantages of the embodiment of the invention clearer, below in conjunction with the embodiment of the present invention
In attached drawing, the present invention is applied by the technical solution in example is clearly and completely described, it is clear that described embodiment is this
Invention a part of the embodiment, instead of all the embodiments.Embodiments of the present invention, which are generally described and illustrated herein in the accompanying drawings
Device can arrange and design with a variety of different configurations.
Therefore, the detailed description of the embodiment of the present invention provided in the accompanying drawings is not intended to limit below claimed
The scope of the present invention, but be merely representative of selected embodiment of the invention.Based on the embodiments of the present invention, this field is common
Technical staff's every other embodiment obtained without creative efforts belongs to the model that the present invention protects
It encloses.
It should also be noted that similar label and letter indicate similar terms in following attached drawing, therefore, once a certain Xiang Yi
It is defined in a attached drawing, does not then need that it is further defined and explained in subsequent attached drawing.
In the description of the present invention, it is also necessary to which explanation is unless specifically defined or limited otherwise, term " setting ",
" connection " shall be understood in a broad sense, for example, it may be being fixedly connected, may be a detachable connection, or be integrally connected；It can be
Mechanical connection, is also possible to be electrically connected；It can be directly connected, two can also be can be indirectly connected through an intermediary
Connection inside element.For the ordinary skill in the art, above-mentioned term can be understood in the present invention with concrete condition
In concrete meaning.
Referring to Fig. 2, a kind of switching circuit 100 provided in an embodiment of the present invention, the switching circuit 100 be applied to include
The signal acquiring system 10 of operational amplifier circuit 200, the switching circuit 100 include the first sub switch Q1, the second sub switch Q2 and
Voltage feedback circuit 110.
Wherein, the first end of the first sub switch Q1 connects as the input terminal and external equipment of the switching circuit 100
Connect, second end is connect with the first end of the second sub switch Q2, the second end of the second sub switch Q2 is as the switch
The output end of circuit 100 is simultaneously connect, the homophase input of the operational amplifier circuit 200 with the inverting input terminal of the operational amplifier circuit 200
End is connect with a power supply, and the input terminal of the voltage feedback circuit 110 is connect with the power supply, output end is connected to described first
Between sub switch Q1 and the second sub switch Q2.
By above-mentioned setting, in carrying out signal acquisition process, and when disconnecting the switching circuit 100, i.e., will
When first sub switch Q1 and the second sub switch Q2 is disconnected, under the action of voltage feedback circuit 110 and according to operational amplifier circuit 200
The short principle of void, make the same phase of the voltage and the operational amplifier circuit 200 between the first sub switch Q1 and the second sub switch Q2
The voltage of input terminal tends to be identical, so as to enter the inverting input terminal of the operational amplifier circuit 200 by the second sub switch Q2
Leakage current be eliminated, and then effectively avoid carrying out introducing when signal acquisition and cause voltage to influence the feelings of signal acquisition result
Condition.
Wherein, the first sub switch Q1 and the second sub switch Q2 can be electronic switch, be also possible to regular tap.
In the present embodiment, the first sub switch Q1 and the second sub switch Q2 is respectively electronic switch, and the electronics
The control terminal of switch is electrically connected with the controller in the signal acquiring system 10, to connect on-off under the action of the controller
The connection between the first end and second end of the first sub switch Q1 is opened, and is connected to or disconnects the second sub switch Q2's
Connection between first end and second end.
Wherein, the electronic switch, which can be, is made of one or more relays, metal-oxide-semiconductor or triode.
In the present embodiment, the electronic switch is made of single metal-oxide-semiconductor, or by a PMOS tube and a NMOS
Pipe parallel connection is constituted, and when the electronic switch is made of a PMOS tube and a NMOS tube parallel connection, the control of the PMOS tube
The control terminal (grid) of end processed and the NMOS tube is connect with the controller respectively, and the control terminal of the PMOS tube and the NMOS tube
Control terminal level it is opposite.
Wherein, when being made of single metal-oxide-semiconductor, which can be NMOS tube, be also possible to PMOS tube, and should
The control terminal (grid) of metal-oxide-semiconductor is connect with the controller.
The electronic device that the operational amplifier circuit 200 includes can be capacitor, operational amplifier etc., not limit specifically herein
It is fixed.
In the present embodiment, the operational amplifier circuit 200 includes second operational amplifier A2 and first capacitor C1, and described first
Input terminal as the operational amplifier circuit 200 after the one end capacitor C1 is connect with the out-phase input terminal of the second operational amplifier A2
It is connect with the second end of the second sub switch Q2, the other end of the first capacitor C1 is with the second operational amplifier A2's
Output end connection, the non-inverting input terminal of the second operational amplifier A2 as the operational amplifier circuit 200 non-inverting input terminal with
The power supply connection.
Wherein, the voltage feedback circuit 110 can be is made of devices such as voltage follower and electronic switches, as long as energy
Enough so that the voltage between the first sub switch Q1 and the second sub switch Q2 is maintained at the non-inverting input terminal with the operational amplifier circuit 200
Voltage it is identical.
Incorporated by reference to Fig. 3, in the present embodiment, the voltage feedback circuit 110 may include third sub switch Q3 and biasing
Generation circuit, the first end of the third sub switch Q3 is connected to the second end of the first sub switch Q1 and second son is opened
Close Q2 first end between, second end connect with the first end of the offset generating circuit, the second of the offset generating circuit
End is connect with the power supply.
In the present embodiment, the offset generating circuit includes the first operational amplifier A1, first operational amplifier
The out-phase input terminal of A1 is connect with output end, non-inverting input terminal is connect with the power supply, output end is connected to first son and opens
It closes between Q1 and the second sub switch Q2.
Specifically, to be connected between the voltage feedback circuit 110 and the first sub switch Q1 and the second sub switch Q2
Position centered on point O, connect with the non-inverting input terminal of the non-inverting input terminal of operational amplifier circuit 200 and the first operational amplifier A1
The voltage of power supply is illustrated for being VCOM, and the output end of the offset generating circuit passes through third sub switch Q3 and central point
The non-inverting input terminal of O connection, input terminal and operational amplifier circuit 200 connects and voltage is VCOM, since offset generating circuit will input
Voltage carries out the duplication that ratio is 1:1 and the second end for being output to third sub switch Q3, therefore third sub switch Q3 is in connected state
Under state, the voltage of first end is also VCOM, and the input terminal of switching circuit 100 passes through the first sub switch Q1 and the second sub switch Q2
It is attached with the inverting input terminal of operational amplifier circuit 200.
When the switches are opened, i.e. the first sub switch Q1 and the second sub switch Q2 are disconnected, when third sub switch Q3 is closed, root
According to the short principle of void of operational amplifier circuit 200, so that the voltage at the second both ends sub switch Q2 is VCOM, i.e., operational amplifier circuit 200 is same
Phase input terminal and out-phase input terminal are VCOM.Therefore, the out-phase input terminal of operational amplifier circuit 200 is entered by the second sub switch Q2
Leakage current be eliminated.That is the second sub switch Q2 leakage current is Ileak2=Vdiff2/Rs2, wherein Vdiff2 is that the second son is opened
The voltage difference and Vdiff2 ≈ 0 at the both ends Q2 are closed, then Ileak2 ≈ 0, therefore resistance Rs2 is turned off by the second sub switch Q2 and is introduced
Leakage current to operational amplifier circuit 200 is eliminated.The input terminal voltage of first sub switch Q1 is Vin (t), the first sub switch Q1
Voltage when output end, that is, central point O voltage is the output end by third sub switch Q3 offset generating circuit is VCOM, the
The leakage current that one sub switch Q1 is generated are as follows:Since central point O passes through third sub switch Q3
It is connect with the output end of offset generating circuit, therefore Ileak1 is eliminated by offset generating circuit, it will not be to the different of operational amplifier circuit 200
Phase input terminal has an impact.
When switching circuit 100 is closed, i.e., will the first sub switch Q1 and the second sub switch Q2 closure, by described the
When three sub switch Q3 are disconnected, analog signal is entered by the input terminal of switching circuit 100, by of the first sub switch Q1 and second
Switch Q2 is input to the inverting input terminal of the operational amplifier circuit 200, according to the short principle of void of amplifier, so that operational amplifier circuit 200
Inverting input terminal voltage Vcia (t) is approximately equal with non-inverting input terminal voltage VCOM.The voltage of central point O is approximately VCOM, this
When, the switch drain of third sub switch Q3 is Ileak3=Vdiff3/Rs3, and Vdiff3 is the voltage difference at third sub switch both ends,
And Vdiff3 ≈ 0, then Ileak3 ≈ 0, therefore, the leakage current influence of third sub switch Q3 is also eliminated.
Referring to Fig. 4, on the basis of the above, the present invention also provides a kind of signal acquiring system 10, the signal acquisition system
System 10 includes operational amplifier circuit 200 and above-mentioned switching circuit 100, and the switching circuit 100 is electrically connected with operational amplifier circuit 200,
Its specific electric connection mode is referred to the description to switching circuit 100 above.
It is also possible to it should be noted that the switching circuit 100 for including in the signal acquiring system 10 can be one
It is multiple, it will be understood that when it is multiple for needing the analog signal that is acquired, in requisition for switching circuit 100 be also it is multiple,
In addition, the quantity of required operational amplifier circuit 200 is either one or more, can be with when switching circuit 100 is multiple
Understand, when the quantity of operational amplifier circuit 200 is multiple, each switching circuit 100 can be connect with an operational amplifier circuit 200, when
When the quantity of operational amplifier circuit 200 is one, each switching circuit 100 is connect with an operational amplifier circuit 200 respectively.
Optionally, in the present embodiment, the signal acquiring system 10 include sensor 300, multiple switch circuit 100 with
And an operational amplifier circuit 200, each sensor 300 are correspondingly connected with a switching circuit 100 respectively, and each switch
Circuit 100 is connect with the operational amplifier circuit 200 respectively.
Each switching circuit 100 is specially the output of each switching circuit 100 with the connection type of the operational amplifier circuit 200 respectively
End is connect with the out-phase input terminal of the operational amplifier circuit 200 respectively.
Wherein, the sensor 300 can be, but not limited to sound transducer, temperature sensor, angular transducer, pressure biography
Sensor or position sensor etc., are not specifically limited herein.
It is fingerprint acquisition system with the signal acquiring system 10, the sensor 300 further includes sensor devices D and parasitism
It is illustrated for capacitor C2, wherein first end and power supply device after the sensor devices D and parasitic capacitance C2 are in parallel connect
It connects, the other end is connect with the input terminal of the switching circuit 100.
Specifically, within a certain period of time, fingerprint is adopted when the sensor 300 includes sensor devices D and parasitic capacitance C2
The strong and weak generation charge signal Qs that each sensor 300 in collecting system shines according to exterior light.Such as first sensor in Fig. 4
When 300 work, useful signal Qs1 is transferred to operational amplifier circuit 200 and is handled and is exported, at this time the letter of other sensors 300
Number Qs (n) is maintained on the voltage of respective parasitic capacitance C2, other are closed the switch, and are not influenced on operational amplifier circuit 200.This hair
Leakage current in 100 mouthfuls of bright middle switching circuit is eliminated, therefore, even if when the quantity of sensor 300 is very big, because of switch drain
Caused signal-to-noise ratio reduction is also eliminated.
To sum up, a kind of switching circuit 100 and signal acquiring system 10 provided by the invention, switching circuit 100 include first
Sub switch Q1, the second sub switch Q2 and voltage feedback circuit 110, the first end of the first sub switch Q1 is as switching circuit 100
Input terminal is connect with external equipment, second end is connect with the first end of the second sub switch Q2, and the second end of the second sub switch Q2 is made
For switching circuit 100 output end and connect with the inverting input terminal of operational amplifier circuit 200, the non-inverting input terminal of operational amplifier circuit 200
Connect with a power supply, the input terminal of voltage feedback circuit 110 is connect with the power supply, output end be connected to the first sub switch Q1 with
Between second sub switch Q2, when carrying out signal acquisition and disconnecting switching circuit 100, to make of the first sub switch Q1 and second
The voltage of voltage and the non-inverting input terminal of operational amplifier circuit 200 between switch Q2 tends to be identical, so as to pass through the second sub switch Q2
Electric leakage into the inverting input terminal of operational amplifier circuit 200 is eliminated by stream, and then avoids 200 output end of influence of leakage current operational amplifier circuit
The voltage of output is to influence signal acquisition result.
It should be noted that, in this document, relational terms such as first and second and the like are used merely to a reality
Body or operation are distinguished with another entity or operation, are deposited without necessarily requiring or implying between these entities or operation
In any actual relationship or order or sequence.Moreover, term " includes " or any other variant are intended to nonexcludability
Include so that include a series of elements process, method, article or equipment not only include those elements, but also
Including other elements that are not explicitly listed, or further include for this process, method, article or equipment intrinsic want
Element.In the absence of more restrictions, the element limited by sentence "including a ...", it is not excluded that including described want
There is also other identical elements in the process, method, article or equipment of element.
The above description is merely a specific embodiment, but scope of protection of the present invention is not limited thereto, any
Those familiar with the art in the technical scope disclosed by the present invention, can easily think of the change or the replacement, and should all contain
Lid is within protection scope of the present invention.
Claims (10)
1. a kind of switching circuit, applied to the signal acquiring system including operational amplifier circuit, which is characterized in that the switching circuit packet
Include the first sub switch, the second sub switch and voltage feedback circuit；
The first end of first sub switch connect as the input terminal of the switching circuit with external equipment, second end with it is described
The first end of second sub switch connects, the second end of second sub switch as the switching circuit output end and with it is described
The inverting input terminal of operational amplifier circuit connects, and the non-inverting input terminal of the operational amplifier circuit is connect with a power supply, the Voltage Feedback electricity
The input terminal on road and the power supply connection, output end be connected between first sub switch and second sub switch, with
When carrying out signal acquisition and disconnecting the switching circuit, i.e., when disconnecting the first sub switch and the second sub switch, in the electricity
Under the action of pressing feed circuit, make the same phase of the voltage and the operational amplifier circuit between first sub switch and the second sub switch
The voltage of input terminal is identical, so as to enter the leakage current quilt of the inverting input terminal of the operational amplifier circuit by second sub switch
It eliminates.
2. switching circuit according to claim 1, which is characterized in that the voltage feedback circuit include third sub switch and
Offset generating circuit, the first end of the third sub switch is connected to the second end of first sub switch and second son is opened
Between the first end of pass, second end connect with the first end of the offset generating circuit, the second end of the offset generating circuit
It is connect with the power supply.
3. switching circuit according to claim 2, which is characterized in that the offset generating circuit includes the first operation amplifier
Device, the out-phase input terminal of first operational amplifier is connect with output end, non-inverting input terminal is connect with the power supply, output end
It is connected between first sub switch and the second sub switch.
4. switching circuit according to claim 2, which is characterized in that the third sub switch is electronic switch, and the electricity
The control terminal of sub switch is electrically connected with the controller in the signal acquiring system, to connect on-off under the action of the controller
Open the connection between the first end and second end of the third sub switch.
5. switching circuit according to claim 1, which is characterized in that first sub switch and the second sub switch are respectively
Electronic switch, and the control terminal of the electronic switch is electrically connected with the controller in the signal acquiring system, in the control
The connection for being connected to or disconnecting under the action of device between the first end and second end of first sub switch, and connection or disconnection institute
State the connection between the first end and second end of the second sub switch.
6. switching circuit according to claim 5, which is characterized in that the electronic switch is made of single metal-oxide-semiconductor, or
Person is made of a PMOS tube and a NMOS tube parallel connection, and when the electronic switch is by a PMOS tube and a NMOS tube
When parallel connection is constituted, the control terminal of the control terminal of the PMOS tube and the NMOS tube is connect with the controller respectively, and the PMOS tube
Control terminal it is opposite with the level of the control terminal of the NMOS tube.
7. switching circuit according to claim 1, which is characterized in that the operational amplifier circuit include second operational amplifier and
First capacitor, described first capacitor one end are electric as the amplifier after connecting with the out-phase input terminal of the second operational amplifier
The input terminal on road is connect with the second end of second sub switch, the other end of the first capacitor and second operation amplifier
The output end of device connects, non-inverting input terminal and institute of the non-inverting input terminal of the second operational amplifier as the operational amplifier circuit
State power supply connection.
8. a kind of signal acquiring system, which is characterized in that including being opened described in operational amplifier circuit and claim 1-7 any one
Powered-down road, switching circuit are connect with the operational amplifier circuit.
9. signal acquiring system according to claim 8, which is characterized in that the signal acquiring system include sensor,
Multiple switch circuit and an operational amplifier circuit, each sensor are correspondingly connected with a switching circuit respectively, and each institute
Switching circuit is stated to connect with the operational amplifier circuit respectively.
10. signal acquiring system according to claim 9, which is characterized in that the sensor includes sensor devices and posts
Raw capacitor, and the first end after the sensor devices and parasitic capacitance in parallel is connect with power supply device, the other end and the switch
The input terminal of circuit connects.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811519922.8A CN109379067B (en) | 2018-12-12 | 2018-12-12 | Switching circuit and signal acquisition system |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811519922.8A CN109379067B (en) | 2018-12-12 | 2018-12-12 | Switching circuit and signal acquisition system |
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| CN109379067A true CN109379067A (en) | 2019-02-22 |
| CN109379067B CN109379067B (en) | 2024-09-03 |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
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| JP2015154093A (en) * | 2014-02-10 | 2015-08-24 | 三菱電機株式会社 | Switched capacitor circuit |
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