CN108037787A - A kind of A/D chip input voltages limiter protection circuit - Google Patents
A kind of A/D chip input voltages limiter protection circuit Download PDFInfo
- Publication number
- CN108037787A CN108037787A CN201711187497.2A CN201711187497A CN108037787A CN 108037787 A CN108037787 A CN 108037787A CN 201711187497 A CN201711187497 A CN 201711187497A CN 108037787 A CN108037787 A CN 108037787A
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- Prior art keywords
- voltage
- operational amplifier
- amplitude limit
- negative
- chip input
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
- G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
- G05F1/10—Regulating voltage or current
- G05F1/46—Regulating voltage or current wherein the variable actually regulated by the final control device is dc
- G05F1/56—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices
- G05F1/561—Voltage to current converters
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- General Physics & Mathematics (AREA)
- Radar, Positioning & Navigation (AREA)
- Automation & Control Theory (AREA)
- Tone Control, Compression And Expansion, Limiting Amplitude (AREA)
Abstract
A kind of A/D chip input voltages limiter protection circuit of the present invention, belongs to the data acquisition technology field of highly reliable computer system.The circuit is built by operational amplifier, diode and resistance and formed, dexterously using drooping characteristic of the negative-feedback characteristic of ideal operational amplificr, saturation output characteristics, the one-way conduction characteristic of diode and resistance etc., the function to A/D chip input voltage amplitude limits is realized.Circuit in the present invention can realize positive voltage and negative voltage double limiting by selecting different resistance values, it can be achieved that the accurate amplitude limit of any amplitude to A/D chips front end input voltage.When the input voltage of A/D chips is in clipping range, the amplitude limiter circuit is on primary circuit without influence.This method is simple and practical, and cost is relatively low.
Description
Technical field
A kind of A/D chip input voltages limiter protection circuit of the present invention belongs to the data acquisition skill of highly reliable computer system
Art field.
Background technology
In highly reliable circuit design, the reliability of chip is the content that must take into consideration, and the reliability of chip is by various aspects
The influence of factor, electric stress are one of them.Each input interface voltage request of chip is limited in recommendation, to avoid because super
Crossing recommendation reduces the reliability of chip, causes its service life to reduce or even damage.The voltage conversion input terminal of A/D chips leads to
The scope for fixation is often required, and commonly used multy-way switching mode completes the collecting work of multi-analog input, to prevent
Because it is exterior certain input voltage causes A/D conversion chips reliability to reduce or damage higher than the voltage range recommended all the way, can in height
By in application, A/D front ends input voltage amplitude limit becomes a kind of required design.
There are the design voltage that limiting voltage value is limited to selected TVS pipe, nothing for the mode of usually used TVS pipe amplitude limit
Method arbitrarily adjusts amplitude limit amplitude and can not complete the demand of accurate amplitude limit, and in order to overcome these problems, the present invention designs a kind of A/D
Chip input saturation protects circuit, and any amplitude, two-way, accurate amplitude limit can be carried out to input voltage.
The content of the invention
The purpose of the present invention is：A kind of circuit is designed, it is true by the circuit when A/D chip input voltages exceed amplitude limit value
A/D front ends input voltage is protected in the range of amplitude limit value, when A/D front ends input voltage is when within amplitude limit value scope, to circuit work(
Can be with performance without influence.
Technical scheme：A kind of A/D chip input voltages limiter protection circuit, the circuit include, resistance R1,
One U1 of operational amplifier, two U2 of operational amplifier, three U3 of operational amplifier, one D1 of diode, two D2 of diode；
Input signal Vi is connected to one end of resistance R1, and the other end of resistance R1 is connected to one U1's of operational amplifier at the same time
Negative terminal, the negative terminal of two U2 of operational amplifier, the anode of one D1 of diode, the negative terminal of two D2 of diode, and operational amplifier three
The anode of U3, the positive termination amplitude limit negative sense of positive termination the amplitude limit forward voltage Vp, two U2 of operational amplifier of one U1 of operational amplifier
The negative terminal of one D1 of output termination diode of voltage Vn, one U1 of operational amplifier, the output termination two level of two U2 of operational amplifier
The anode of two D2 of pipe, the negative terminal of three U3 of operational amplifier are connected to three U3 output terminals of operational amplifier, and three U3's of operational amplifier is defeated
Outlet output voltage Vo.
When A/D chip input voltages are less than amplitude limit negative voltage Vn, A/D chip input voltages can be clamped down on amplitude limit and born
To voltage Vn, when A/D chip input voltages are more than amplitude limit forward voltage Vp, A/D chip input voltages can be clamped down on amplitude limit
Forward voltage Vp, when A/D chip input voltages Vi is between amplitude limit negative voltage Vn and amplitude limit forward voltage Vp, negative sense containing amplitude limit
Voltage Vn and amplitude limit forward voltage Vp, on A/D chip input voltages without influence.
By adjusting the resistance value of resistance in circuit, the accurate amplitude limit of any amplitude can be realized.
Amplitude limit forward voltage Vp can become the voltage of 10V, the positive electricity of amplitude limit by carrying out electric resistance partial pressure to P15V power supplys
Vn is pressed to become the voltage of -10V by carrying out electric resistance partial pressure to N15V power supplys.
It is an advantage of the invention that：
1. the negative-feedback characteristic of operational amplifier was not only used but also had used the saturation output characteristics of operational amplifier；
2. it can realize any amplitude amplitude limit；
3. it can realize double limiting；
4. it can realize accurate amplitude limit；
5. input voltage is in clipping range, the amplitude limiter circuit is on primary circuit without influence；
6. the invention is simple and practical, cost is relatively low.
Brief description of the drawings
Fig. 1 is circuit diagram of the present invention
Fig. 2 is circuit simulation figure one of the present invention
Wherein ViFor frequency 100Hz, duty cycle 50%, amplitude is the square wave of 10V, and resistance R1-R5 values are 10K Ω
(V at this timen=-7.5V, VP=7.5V), the simulation result figure of circuit of the present invention, wherein passage 1 are Vi, passage 2 is Vo
Fig. 3 is circuit simulation figure two of the present invention
Wherein ViFor frequency 50Hz, amplitude is the sine wave of 12V, resistance value R1=R2=R4=10K Ω, R3=R5=
5K Ω (V at this timen=-10V, VP=10V), the simulation result figure of circuit of the present invention, wherein passage 1 are Vi, passage 2 is Vo
Embodiment
A kind of A/D chip input voltages limiter protection circuit, the circuit include, resistance R1, one U1 of operational amplifier, fortune
Calculate two U2 of amplifier, three U3 of operational amplifier, one D1 of diode, two D2 of diode；
Input signal Vi is connected to one end of resistance R1, and the other end of resistance R1 is connected to one U1's of operational amplifier at the same time
Negative terminal, the negative terminal of two U2 of operational amplifier, the anode of one D1 of diode, the negative terminal of two D2 of diode, and operational amplifier three
The anode of U3, the positive termination amplitude limit negative sense of positive termination the amplitude limit forward voltage Vp, two U2 of operational amplifier of one U1 of operational amplifier
The negative terminal of one D1 of output termination diode of voltage Vn, one U1 of operational amplifier, the output termination two level of two U2 of operational amplifier
The anode of two D2 of pipe, the negative terminal of three U3 of operational amplifier are connected to three U3 output terminals of operational amplifier, and three U3's of operational amplifier is defeated
Outlet output voltage Vo.
When A/D chip input voltages are less than amplitude limit negative voltage Vn, A/D chip input voltages can be clamped down on amplitude limit and born
To voltage Vn, when A/D chip input voltages are more than amplitude limit forward voltage Vp, A/D chip input voltages can be clamped down on amplitude limit
Forward voltage Vp, when A/D chip input voltages Vi is between amplitude limit negative voltage Vn and amplitude limit forward voltage Vp, negative sense containing amplitude limit
Voltage Vn and amplitude limit forward voltage Vp, on A/D chip input voltages without influence.
By adjusting the resistance value of resistance in circuit, the accurate amplitude limit of any amplitude can be realized.
Amplitude limit forward voltage Vp can become the voltage of 10V, the positive electricity of amplitude limit by carrying out electric resistance partial pressure to P15V power supplys
Vn is pressed to become the voltage of -10V by carrying out electric resistance partial pressure to N15V power supplys.
The present invention will be described in detail below in conjunction with the accompanying drawings.
The circuit includes one U1 of operational amplifier, two U2 of operational amplifier, three U3 of operational amplifier, one D1 of diode, two
Pole pipe two D2 and resistance R1-R5 are formed.Realize circuit as shown in Figure 1.
The circuit operation principle：For simplicity, computational reasoning is carried out with ideal operational amplificr characteristic.
It is i by the input terminal electric current of one U1 of operational amplifieru1+=0 understands VPAs shown in formula (1)：
Work as Vu1-Less than Vu1+(=Vp) when, it is assumed that without negative feedback loop, Vu1oTo export saturation state, output voltage is just
Supply voltage is more than Vu1-, one D1 diodes of diode are cut-off state, identical with hypothesis, and one U1 of operational amplifier cannot be formed
Negative-feedback.By iu1-=0 and iu3+=0 understands, resistance R1 is without pressure drop, while three U3 of operational amplifier mutually follows circuit to be same, then
VoAs shown in formula (2)：
Vo=Vi………………………………(2)
Work as Vu1-More than Vu1+(=Vp) when, it is assumed that without negative feedback loop, Vu1oTo export saturation state, voltage is negative supply
Voltage is less than Vu1-, one D1 of diode is conducting state, different from hypothesis, and one U1 of operational amplifier forms negative feedback loop, by transporting
Calculate amplifier characteristic Vu1-=Vu1+(=VP) understand, resistance R1 pressure drops are Vi-VP, while three U3 of operational amplifier mutually follows to be same
Circuit, then VoAs shown in formula (3)：
Vo=VP………………………………(3)
It is i by the input terminal electric current of two U2 of operational amplifieru2+=0 understands VnAs shown in formula (4)：
Work as Vu2-More than Vu2+(=Vn) when, it is assumed that without negative feedback loop, Vu2oTo export saturation state, output voltage is negative
Supply voltage is less than Vu2-, two D2 diodes of diode are cut-off state, identical with hypothesis, and two U2 of operational amplifier cannot be formed
Negative-feedback, by iu2-=0 and iu3+=0 understands, resistance R1 is without pressure drop, while three U3 of operational amplifier mutually follows circuit to be same, then
VoAs shown in formula (5)：
Vo=Vi………………………………(5)
Work as Vu2-Less than Vu2+(=Vn) when, it is assumed that without negative feedback loop, Vu2oTo export saturation state, voltage is positive supply
Voltage is more than Vu2-, two D2 of diode is conducting state, different from hypothesis, and two U2 of operational amplifier forms negative-feedback circuit, by transporting
Calculate amplifier characteristic Vu1-=Vu1+(=Vn) understand, resistance R1 pressure drops are Vi-Vn, while three U3 of operational amplifier mutually follows to be same
Circuit, then VoAs shown in formula (6)：
Vo=Vn………………………………(6)
Design more than summarizing understands that amplitude limiter circuit parameter is as shown in table 1.
1 amplitude limiter circuit parameter of table
VPAnd VnRealization both can use electric resistance partial pressure produce, can also use high-precision reference source produce.
The selection of two U2 of one U1 of operational amplifier and operational amplifier mainly considers output current parameter, operational amplifier one
U1 output currents should be not less than (Vi-VP)/R1 (A), two U2 output currents of operational amplifier should be not less than (Vi-Vn)/R1(A)。
Resistance R1 need to consider that parameter is mainly its rated power, its rated power should be not less than (Vi-VP)2/ R1 and (Vi-Vn
)2The maximum of/R1.
Resistance R2-R5 selections consider that parameter is resistance precision, its precision should be not less than required limiting voltage precision.
Three U3 of operational amplifier then needs to carry out matching choosing according to the A/D circuit bandwidths characteristic behind three U3 of operational amplifier
Select, three U3 bandwidth of operational amplifier should be not less than the circuit bandwidth behind three U3 of operational amplifier.If A/D chips front end is
When being matched with operational amplifier, three U3 of operational amplifier can cancel.
Claims (4)
1. a kind of A/D chip input voltages limiter protection circuit, it is characterised in that the circuit includes resistance R1, operation amplifier
One U1 of device, two U2 of operational amplifier, three U3 of operational amplifier, one D1 of diode, two D2 of diode；
Input signal Vi is connected to one end of resistance R1, and the other end of resistance R1 is connected to the negative of one U1 of operational amplifier at the same time
End, the negative terminal of two U2 of operational amplifier, the anode of one D1 of diode, the negative terminal of two D2 of diode, and three U3 of operational amplifier
Anode, the positive termination amplitude limit negative sense electricity of positive termination the amplitude limit forward voltage Vp, two U2 of operational amplifier of one U1 of operational amplifier
Press Vn, the negative terminal of one D1 of output termination diode of one U1 of operational amplifier, the output termination diode of two U2 of operational amplifier
The anode of two D2, the negative terminal of three U3 of operational amplifier are connected to three U3 output terminals of operational amplifier, the output of three U3 of operational amplifier
Hold output voltage Vo.
2. a kind of A/D chip input voltages limiter protection circuit according to claim 1, it is characterised in that when A/D chips
When input voltage is less than amplitude limit negative voltage Vn, A/D chip input voltages can be clamped down on to amplitude limit negative voltage Vn, when A/D cores
When piece input voltage is more than amplitude limit forward voltage Vp, A/D chip input voltages can be clamped down on to amplitude limit forward voltage Vp, work as A/D
For chip input voltage Vi between amplitude limit negative voltage Vn and amplitude limit forward voltage Vp, the Vn of negative voltage containing amplitude limit and amplitude limit are positive
Voltage Vp, on A/D chip input voltages without influence.
A kind of 3. A/D chip input voltages limiter protection circuit as claimed in claim 1, it is characterised in that：By adjusting electricity
The resistance value of resistance in road, can realize the accurate amplitude limit of any amplitude.
A kind of 4. A/D chip input voltages limiter protection circuit as claimed in claim 1, it is characterised in that the positive electricity of amplitude limit
Vp is pressed to become the voltage of 10V by carrying out electric resistance partial pressure to P15V power supplys, amplitude limit forward voltage Vn can be by N15V
Power supply, which carries out electric resistance partial pressure, becomes the voltage of -10V.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711187497.2A CN108037787A (en) | 2017-11-23 | 2017-11-23 | A kind of A/D chip input voltages limiter protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711187497.2A CN108037787A (en) | 2017-11-23 | 2017-11-23 | A kind of A/D chip input voltages limiter protection circuit |
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| Publication Number | Publication Date |
|---|---|
| CN108037787A true CN108037787A (en) | 2018-05-15 |
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ID=62092559
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201711187497.2A Pending CN108037787A (en) | 2017-11-23 | 2017-11-23 | A kind of A/D chip input voltages limiter protection circuit |
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| CN (1) | CN108037787A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109194108A (en) * | 2018-11-21 | 2019-01-11 | 西安埃克森电源有限公司 | A kind of variable-frequency power sources output short circuit protection control method |
| CN112910431A (en) * | 2021-01-20 | 2021-06-04 | 四川湖山电器股份有限公司 | Audio frequency amplitude limiting circuit and equipment with power supply rail tracking characteristic based on single power supply |
Citations (5)
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|---|---|---|---|---|
| CN101753110A (en) * | 2008-11-27 | 2010-06-23 | 雅马哈株式会社 | Amplifier |
| CN202487965U (en) * | 2012-02-01 | 2012-10-10 | 深圳市联赢激光股份有限公司 | Semiconductor laser unit temperature controlling circuit |
| CN204145423U (en) * | 2014-10-08 | 2015-02-04 | 兰州飞行控制有限责任公司 | The adjustable amplitude limiter circuit of a kind of accurate bidirectional |
| CN104993829A (en) * | 2015-07-15 | 2015-10-21 | 株洲南车时代电气股份有限公司 | Switching value input acquisition circuit suitable for wide-range level |
| CN105406866A (en) * | 2015-12-10 | 2016-03-16 | 中国航空工业集团公司西安航空计算技术研究所 | Overvoltage protection method for analog-digital conversion circuit |
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2017
- 2017-11-23 CN CN201711187497.2A patent/CN108037787A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101753110A (en) * | 2008-11-27 | 2010-06-23 | 雅马哈株式会社 | Amplifier |
| CN202487965U (en) * | 2012-02-01 | 2012-10-10 | 深圳市联赢激光股份有限公司 | Semiconductor laser unit temperature controlling circuit |
| CN204145423U (en) * | 2014-10-08 | 2015-02-04 | 兰州飞行控制有限责任公司 | The adjustable amplitude limiter circuit of a kind of accurate bidirectional |
| CN104993829A (en) * | 2015-07-15 | 2015-10-21 | 株洲南车时代电气股份有限公司 | Switching value input acquisition circuit suitable for wide-range level |
| CN105406866A (en) * | 2015-12-10 | 2016-03-16 | 中国航空工业集团公司西安航空计算技术研究所 | Overvoltage protection method for analog-digital conversion circuit |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109194108A (en) * | 2018-11-21 | 2019-01-11 | 西安埃克森电源有限公司 | A kind of variable-frequency power sources output short circuit protection control method |
| CN112910431A (en) * | 2021-01-20 | 2021-06-04 | 四川湖山电器股份有限公司 | Audio frequency amplitude limiting circuit and equipment with power supply rail tracking characteristic based on single power supply |
| CN112910431B (en) * | 2021-01-20 | 2022-12-30 | 四川湖山电器股份有限公司 | Audio frequency amplitude limiting circuit and equipment with power supply rail tracking characteristic based on single power supply |
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Application publication date: 20180515 |
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| RJ01 | Rejection of invention patent application after publication |