CN207910749U - A kind of window voltage comparison circuit - Google Patents

Abstract

The utility model discloses a kind of window voltage comparison circuits, including：First operational amplifier, second operational amplifier, the first photoelectrical coupler and the second photoelectrical coupler；First operational amplifier and second operational amplifier control the comparing voltage value of signal and window width control signal change window voltage comparison circuit according to voltage to be compared, the window's position of input, first photoelectrical coupler and the second photoelectrical coupler export comparison result according to the comparing voltage value of window voltage comparison circuit, realize that window voltage compares.Window position and window width can be automatically adjusted using the window voltage comparison circuit of the utility model, realize that the tracking for treating comparison voltage is compared.

Description

A Window Voltage Comparator Circuit

technical field

The utility model relates to the technical field of voltage signal measurement and control, in particular to a window voltage comparison circuit.

Background technique

The window voltage comparison circuit is a voltage comparator used to judge whether the input voltage is between two known levels, and is widely used in automatic detection circuits, fault detection circuits, A/D conversion circuits, high-speed sampling circuits, waveform Transformation circuit, power supply voltage monitoring circuit, alarm and electronic measurement technology. Taking the detection of vibration by the automatic detection circuit as an example to illustrate the use of the window voltage comparator, for example, the time history of vibration at a specific point can be the time history of displacement, and the specific point is the time history of the displacement around the basic stable point , and the amplitude of the up and down displacement around the basic stable point will not exceed ±ΔX, that is to say, the vibration of this specific point is carried out within a certain window. , a window voltage comparator circuit is needed to pick up the electrical signal of the vibration displacement.

The existing window voltage comparison circuit is a dual-limit comparator, which mainly uses a dual-voltage comparator and two potentiometers to provide comparison levels. Among them, the adjustment of the window position and window size in the window voltage comparison circuit is through the potentiometer This type of window voltage comparison circuit is suitable for comparison circuits with fixed window positions and window sizes. However, the automatic detection circuit is still taken as an example. For example, since the vibration monitoring is a vibration detection from a specific point to another specific point, when the detected specific points are different, the amplitude of the basic stable point and the basic stable point may be different. change, that is to say, the window position and window size will change during the automatic detection process; while the window position and window size in the existing window voltage comparison circuit cannot follow the change of the detected signal, which will Seriously reduce the comparison accuracy of the circuit. Therefore, the existing window voltage comparison circuit has the problem that the window position and window size cannot be automatically adjusted.

Utility model content

In view of the above problems, the window position and window size in a window voltage comparison circuit of the utility model can be changed automatically following the transformation of the input voltage to be compared, and the window position and window size of the window voltage comparison circuit can be effectively adjusted to realize the comparison Voltage tracking comparison.

In order to solve the above-mentioned technical problems, a window voltage comparison circuit of the present invention includes a first input terminal, a second input terminal, a third input terminal, a first operational amplifier, a second operational amplifier, a first photocoupler, a second Optocoupler and signal output; where,

The first input terminal is connected to the inverting input terminal of the first operational amplifier through a first resistor, and the second input terminal is connected to the inverting input terminal of the first operational amplifier through a second resistor, wherein the The first input terminal is used to input the voltage to be compared, and the second input terminal is used to input the window position control signal, and the window position control signal is used to determine the position of the window centerline; the non-inverting input terminal of the first operational amplifier Grounded, the inverting input terminal of the first operational amplifier is connected to the inverting input terminal of the second operational amplifier through a third resistor and a fourth resistor, and the connection between the third resistor and the fourth resistor A first diode is connected between the point and the output terminal of the first operational amplifier, and a second diode is connected between the output terminal of the first operational amplifier and its inverting input terminal;

The first input terminal is connected to the inverting input terminal of the second operational amplifier through a fifth resistor, and the second input terminal is connected to the inverting input terminal of the second operational amplifier through a sixth resistor. The three input terminals are connected to the inverting input terminal of the second operational amplifier through the seventh resistor, the third input terminal is used to input the window width control signal, and the window width control signal is used to control the width of the window; The non-inverting input of the second operational amplifier is grounded, and the inverting input of the second operational amplifier is connected to the anode of the light-emitting diode in the first photocoupler and the cathode of the light-emitting diode in the second photocoupler through the eighth resistor. connected, the output end of the second operational amplifier is respectively connected to the cathode of the light emitting diode in the first optocoupler and the anode of the light emitting diode in the second optocoupler;

The collector of the phototransistor in the first photocoupler is connected to the emitter of the phototransistor in the second photocoupler and grounded through the ninth resistor, and the emitter of the phototransistor in the first photocoupler is connected to the first straight DC power supply;

The collector of the phototransistor in the second photocoupler is connected to a second DC power supply;

The signal output terminal is connected with the collector of the phototransistor in the first photocoupler and the emitter of the phototransistor in the second photocoupler to output the comparison result.

Compared with the prior art, the window voltage comparison circuit of the utility model determines the jump point of the signal output terminal by the positive or negative of the sum of the voltage to be compared input at the first input terminal and the window position control signal input at the second input terminal , so that the jump point of the signal output terminal changes automatically with the size of the voltage to be compared, which improves the determination accuracy and response speed of the jump point; at the same time, the window center point position in the window voltage formed by the window voltage comparison circuit of the utility model The window position control signal input by the second input terminal is adjusted, and the window width is adjusted by the window width control signal input by the third input terminal, so that the adjustment mode of the window voltage is simple, convenient and sensitive; in addition, the window voltage comparison circuit of the utility model Made from simple components such as operational amplifiers, diodes and resistors, they are inexpensive to manufacture.

As an improvement of the above solution, the resistance value of the first resistor is equal to the resistance value of the second resistor.

As an improvement of the above solution, the resistance values of the fifth resistor, the sixth resistor and the seventh resistor are all equal to the resistance value of the first resistor.

As an improvement to the above solution, the resistance value of the third resistor is 1/2 of the resistance value of the first resistor.

As an improvement of the above solution, the resistance value of the fourth resistor is 1/4 of the resistance value of the first resistor.

As an improvement of the above solution, the first DC power supply is a DC voltage source for providing negative voltage; the second DC power supply is a DC voltage source for providing positive voltage.

Description of drawings

FIG. 1 is a schematic structural diagram of a window voltage comparison circuit in Embodiment 1 of the present invention.

FIG. 2 is a schematic diagram of the voltage transmission characteristics of the window voltage comparison circuit in Embodiment 1 of the present invention.

Detailed ways

In the following description, numerous specific details are set forth in order to provide a full understanding of the present invention. But the utility model can be implemented in many other ways different from this description, and those skilled in the art can do similar promotion without violating the connotation of the utility model, so the utility model is not limited by the specific embodiments disclosed below .

The technical scheme of the utility model is described clearly and completely below in conjunction with specific embodiments and accompanying drawings.

Example 1

As shown in FIG. 1 , it is a schematic structural diagram of a window voltage comparison circuit in Embodiment 1 of the present invention.

The window voltage comparison circuit includes: a first input terminal, a second input terminal, a third input terminal, a first operational amplifier A ₁ , a second operational amplifier A ₂ , a first optocoupler OC ₁ and a second optocoupler OC ₂ ; wherein, the first input terminal is connected to the inverting input terminal of the first operational amplifier _A1 through the first resistor _R2 , and the second input terminal is connected to the inverting input terminal of the first operational amplifier _A1 through the second resistor _R2 , Wherein, the first input terminal is used to input the voltage V _IN to be compared, the second input terminal is used to input the window position control signal V _K , the window position control signal V _K is used to determine the position of the window center line, the first operational amplifier A The noninverting input terminal of ₁ is grounded, the inverting input terminal of the first operational amplifier _A1 is connected with the inverting input terminal of the second operational amplifier _A2 through the third resistor _R3 and the fourth resistor _R4 , and the third resistor _R3 is connected with the inverting input terminal of the second operational amplifier A2. A first diode D1 is connected between the connection point of the fourth resistor _R4 and the output terminal of the first operational amplifier _A1 , and a second diode _D1 is connected between the output terminal of the first operational amplifier _A1 and its inverting input terminal. Diode _D2 ; the first input terminal is connected to the inverting input terminal of the second operational amplifier _A2 through the fifth resistor _R5 , and the second input terminal is connected to the inverting input terminal of the second operational amplifier _A2 through the sixth resistor _R6 terminal, the third input terminal is connected to the inverting input terminal of the second operational amplifier _A2 through the seventh resistor _R7 , the third input terminal is used to input the window width control signal ΔV, and the window width control signal is used to control the width of the window, The noninverting input terminal of the second operational amplifier _A2 is grounded, and the inverting input terminal of the second operational amplifier _A2 is connected with the anode of the light-emitting diode _D3 in the first optocoupler _OC1 and the second optocoupler through the eighth resistor _R8 The cathode of the light-emitting diode _D4 in _OC2 is connected, and the output terminal of the second operational amplifier _A2 is respectively connected to the cathode of the light-emitting diode _D3 in _the first photocoupler _OC1 and the cathode of the light-emitting diode _D4 in the second photocoupler OC2. The anode of the phototransistor T1 in the first photocoupler _OC1 is _connected to the emitter of the phototransistor _T2 in the second photocoupler _OC2 and grounded through the ninth resistor _R9 , the first photocoupler The emitter of the phototransistor _T1 in the device _OC1 is connected to the first DC power supply; the collector of the phototransistor _T2 in the second optocoupler _OC2 is connected to the second DC power supply, wherein the first DC power supply is a DC voltage source , used to provide a negative voltage; the second DC power supply is a DC voltage source used to provide a positive voltage, the signal output terminal V _OUT is connected to the collector of the phototransistor D ₃ in the first photocoupler OC ₁ and the second photocoupler OC The emitters of the phototransistor D ₄ in ₂ are connected to output the comparison result; R ₁ =R ₂ =R ₅ =R ₆ =R ₇ =R, R ₃ =R/2, R ₄ =R/4, R is preset resistance value.

Next, the working principle of the window voltage comparison circuit in Embodiment 1 will be described in detail with reference to FIG. 1 and FIG. 2 .

Since R ₁ =R2=R and the non-inverting input terminal of the first operational amplifier A ₁ is grounded, when the input V _IN and V _K satisfy (V _IN +V _K )<0, the first operational amplifier A ₁ is inverting The input voltage V _G1 of the input terminal <0, that is, the inverting input terminal of the first operational amplifier _A1 inputs a negative voltage, and then the negative voltage is reversed by the first operational amplifier _A1 , the output of the first operational amplifier _A1 Instantaneously output a positive voltage, so that the second diode _D2 is turned on and the first diode _D1 is turned off. At this time, the third resistor _R3 and the fourth resistor _R4 are connected in series and connected to the first operational amplifier A Between the virtual point _G1 of ₁ and the virtual point G2 of the second _operational amplifier _A2 , and the voltage V _G1 of the virtual point _G1 of the first operational amplifier _{A1 ≈0V} , so the voltage of the virtual point of the first operational amplifier _A1 V _G1 has no influence on the second operational amplifier A ₂ , and the second operational amplifier A ₂ is only affected by the three input voltages of V _IN , V _K and ΔV. Moreover, since the voltage V _G2 of the virtual point _G2 of the second operational amplifier _A2 ≈0V, R5=R6=R7=R, the current I _O flowing through the eighth resistor _R8 satisfies the following conditions:

When (V _IN +V _K +ΔV)>0, I _O >0, then the light-emitting diode _D3 in the first photocoupler _OC1 is turned on, and the photosensitive transistor _T1 in the first photocoupler _OC1 receives the light-emitting diode D ₃ emits light and turns on, the light-emitting diode D ₄ in the second photocoupler OC ₂ cuts off, and the phototransistor T ₂ in the second photocoupler OC ₂ does not receive light and turns off, then the output voltage of the signal output terminal V _OUT is the first A DC power supply voltage -E, that is, V _OUT =-E; when (V _IN +V _K +ΔV)<0, I _O <0, then the light-emitting diode _D3 in the first optocoupler _OC1 is cut off, The phototransistor _T1 is cut off without being illuminated by the light-emitting diode _D3 , the light-emitting diode _D4 in the second photocoupler _OC2 is turned on, and the phototransistor _T2 is turned on by the light, then the output voltage of the signal output terminal V _OUT is The voltage of the second DC power supply +E, that is, V _OUT =+E; when (V _IN +V _K +ΔV)=0, I _O =0, then the low-value comparison point voltage V _IN =-V _K - ΔV.

Since R ₁ =R ₂ =R, R ₃ =R/2 and the non-inverting input terminal of the first operational amplifier A ₁ is grounded, when the input V _IN and V _K satisfy (V _IN +V _K )>0, then The input voltage V _G1 of the inverting input terminal of the first operational amplifier A1>0, that is, the inverting input terminal of the first operational amplifier _A1 inputs a positive voltage, and then _the negative voltage is reversed by the first operational amplifier _A1 , The output terminal of the first operational amplifier A ₁ outputs a negative voltage instantaneously, so that the first diode D ₁ is turned on and the second diode D ₂ is turned off. At this time, the first operational amplifier A ₁ and the first resistor R ₁ , The second resistor R ₂ and the third resistor R ₃ form an inverting addition operation circuit, the voltage V _E at the connection point of the third resistor R ₃ and the fourth circuit R ₄ =-(V _IN +V _K )/2, the second Operational amplifier A ₂ is affected by four input voltages V _IN , V _K , ΔV and _VE . Furthermore, since the voltage V _G2 ≈ 0V at the virtual point G ₂ of the second operational amplifier A ₂ , and R ₅ =R ₆ =R ₇ =R, the current I _O flowing through the eighth resistor R ₈ satisfies the following conditions:

When (-V _IN -V _K +ΔV)>0, I _O >0, then the light-emitting diode _D3 in the first photocoupler _OC1 is turned on, and the phototransistor _T1 is turned on by the light emitted by the light-emitting diode _D3 , the light-emitting diode D ₄ in the second photocoupler OC ₂ is cut off, and the photosensitive diode T ₂ is cut off without being illuminated, then the output voltage of the signal output terminal V _OUT is the voltage -E of the first DC power supply, that is, V _OUT =-E ; When (-V _IN -V _K +ΔV)<0, I _O <0, then the light-emitting diode _D3 in the first photocoupler _OC1 is cut off, and the photosensitive diode _T1 is cut off without being illuminated by the light-emitting diode _D3 , the light-emitting diode D ₄ in the second photocoupler OC ₂ is turned on, and the photosensitive diode T ₂ is turned on by light, then the output voltage of the signal output terminal V _OUT is the voltage +E of the second DC power supply, that is, V _OUT =+E ; When (-V _IN -V _K +ΔV)=0, I _O =0, then the high-value comparison point voltage V _IN =-V _K +ΔV is obtained.

As shown in FIG. 2 , it is a schematic diagram of voltage transmission characteristics in the window voltage comparison circuit.

The window width formed by the window voltage comparison circuit of the present utility model is 2ΔV, the low value comparison point voltage is V _IN =-V _K -ΔV, the high value comparison point voltage is V _IN =-V _K +ΔV, and the window center point is - V _K . Therefore, when the size of the input voltage V _K at the second input terminal is adjusted, the window center position of the window voltage comparison circuit can be adjusted, and when the voltage size of the input voltage ΔV at the third input terminal is adjusted, the window voltage comparison circuit can be adjusted. The width of the window can effectively solve the problem that the window position and window size cannot be adjusted in the traditional window voltage comparison circuit, improve the judgment accuracy, and improve the anti-common film interference ability of the window voltage comparison circuit; in addition, the window voltage comparison circuit can also be based on the window The voltage comparator circuit needs to be externally connected with a logic circuit, and the first DC power supply and the second DC power supply with different voltage values are used to meet the requirements of different logic circuits for different logic levels. On the other hand, the window voltage comparison circuit of the present invention also has the advantages of simple circuit structure and low manufacturing cost.

The window voltage comparison circuit of the present utility model changes the window voltage comparison through the positive and negative of the input voltage V _IN to be compared input by the first input terminal and the window position control signal V _K input by the second input terminal (V _IN +V _K ). The comparison voltage value of the circuit, so that the comparison voltage value of the window voltage comparison circuit changes automatically with the change of the voltage V _IN to be compared; wherein, when (V _IN +V _K )<0, the low value comparison voltage of the window voltage comparison circuit V _IN =-V _K -ΔV, and then when V _IN >-V _K -ΔV, the signal output terminal V _OUT of the window voltage comparison circuit outputs the voltage of the first DC power supply -E; when V _IN <-V _K When -ΔV, the signal output terminal V _OUT of the window voltage comparison circuit outputs the voltage +E of the second DC power supply. When (V _IN +V _K )>0, the high-value comparison voltage of the window voltage comparison circuit is V _IN =-V _K +ΔV, and when V _IN <-V _K +ΔV, the signal output of the window voltage comparison circuit The terminal V _OUT outputs the voltage -E of the first DC power supply; when V _IN >-V _K +ΔV, the signal output terminal of the window voltage comparison circuit outputs the voltage +E of the second DC power supply V _OUT .

Preferably, in the window voltage comparison circuit of the present invention, the first resistor R ₁ , the second resistor R ₂ , the third resistor R ₃ , the fourth resistor R ₄ , the fifth resistor R ₅ , the sixth resistor R ₆ , the The seventh resistor R ₇ , the eighth resistor R ₈ and the ninth resistor R ₉ can use resistors with a precision of more than one thousandth to improve the precision of the window voltage comparison circuit.

Preferably, in the window voltage comparison circuit of the present utility model, an operational amplifier with high slew rate, small adjustment time, high input impedance and low output impedance can also be selected as the first operational amplifier _A1 or the second operational amplifier according to the conversion accuracy of the operational amplifier. Operational Amplifier A ₂ .

Preferably, in the window voltage comparison circuit of the present invention, according to the conversion accuracy, high-speed switching diodes with low threshold voltages can be selected as the first diode D ₁ and the second diode D ₂ , and the delay time comparison can be selected Small optocouplers are used as the first optocoupler OC ₁ and the second optocoupler OC ₂ to improve the response speed of the circuit.

The above is only a preferred embodiment of the utility model, and does not limit the utility model in any form, so all content that does not deviate from the technical solution of the utility model, according to the technical essence of the utility model to the above embodiment Any simple modifications, equivalent changes and modifications still fall within the scope of the technical solutions of the present utility model.

Claims (6)

1. A window voltage comparison circuit is characterized by comprising a first input end, a second input end, a third input end, a first operational amplifier, a second operational amplifier, a first photoelectric coupler, a second photoelectric coupler and a signal output end; wherein,

the first input end is connected to the inverting input end of a first operational amplifier through a first resistor, and the second input end is connected to the inverting input end of the first operational amplifier through a second resistor, wherein the first input end is used for inputting a voltage to be compared, the second input end is used for inputting a window position control signal, and the window position control signal is used for determining the position of a window center line; the non-inverting input end of the first operational amplifier is grounded, the inverting input end of the first operational amplifier is connected with the inverting input end of the second operational amplifier through a third resistor and a fourth resistor, a first diode is connected between the connecting point of the third resistor and the fourth resistor and the output end of the first operational amplifier, and a second diode is connected between the output end of the first operational amplifier and the inverting input end of the first operational amplifier;

the first input end is connected with the inverting input end of the second operational amplifier through a fifth resistor, the second input end is connected with the inverting input end of the second operational amplifier through a sixth resistor, the third input end is connected with the inverting input end of the second operational amplifier through a seventh resistor, the third input end is used for inputting a window width control signal, and the window width control signal is used for controlling the width of a window; the non-inverting input end of the second operational amplifier is grounded, the inverting input end of the second operational amplifier is connected with the anode of the light emitting diode in the first photoelectric coupler and the cathode of the light emitting diode in the second photoelectric coupler through an eighth resistor, and the output end of the second operational amplifier is respectively connected with the cathode of the light emitting diode in the first photoelectric coupler and the anode of the light emitting diode in the second photoelectric coupler;

a collector of the photosensitive triode in the first photoelectric coupler is connected with an emitter of the photosensitive triode in the second photoelectric coupler and is grounded through a ninth resistor, and the emitter of the photosensitive triode in the first photoelectric coupler is connected with a first direct-current power supply; the collector of the photosensitive triode in the second photoelectric coupler is connected with a second direct-current power supply;

and the signal output end is connected with a collector electrode of the photosensitive triode in the first photoelectric coupler and an emitter electrode of the photosensitive triode in the second photoelectric coupler so as to output a comparison result.

2. The window voltage comparison circuit of claim 1 wherein the resistance value of the first resistor is equal to the resistance value of the second resistor.

3. The window voltage comparison circuit of claim 2 wherein the resistance values of said fifth resistor, said sixth resistor and said seventh resistor are all equal to the resistance value of said first resistor.

4. The window voltage comparison circuit of claim 3, wherein the resistance value of the third resistor is 1/2 of the resistance value of the first resistor.

5. The window voltage comparison circuit of claim 3, wherein the resistance value of the fourth resistor is 1/4 of the resistance value of the first resistor.

6. The window voltage comparison circuit according to any one of claims 1 to 5, wherein the first DC power supply is a DC voltage source for providing a negative voltage; the second direct current power supply is a direct current voltage source and is used for providing positive voltage.