CN216929988U

CN216929988U - Voltage comparator

Info

Publication number: CN216929988U
Application number: CN202220492398.5U
Authority: CN
Inventors: 刘敬伟; 詹文锋; 陈志彬; 余毅祥
Original assignee: Guoke Optical Core Haining Technology Co ltd
Current assignee: Guoke Optical Core Haining Technology Co ltd
Priority date: 2022-03-08
Filing date: 2022-03-08
Publication date: 2022-07-08
Anticipated expiration: 2032-03-08

Abstract

The utility model discloses a voltage comparator.A unipolar voltage is input into a blocking circuit, the blocking circuit has a function of blocking direct current and alternating current, a direct current signal in the unipolar voltage is filtered, an alternating current signal is output, the amplitude of the alternating current signal is +/-Vpp/2, and Vpp is the difference value of the upper peak value and the lower peak value of the alternating current signal in the unipolar voltage. The voltage divider circuit provides reference voltage for the comparison circuit, the comparison circuit takes the sum of the alternating current signal output by the blocking circuit and the reference voltage as the voltage to be compared, the comparison circuit compares the voltage to be compared with the reference voltage and finally outputs a comparison result, and the amplitude of the alternating current signal is +/-Vpp/2, so that the voltage comparator provided by the embodiment of the utility model can realize that the comparison circuit is turned over when the amplitude of the unipolar voltage is half of the amplitude of the unipolar voltage, and the function of zero-crossing comparison of the unipolar signal is realized.

Description

Voltage comparator

Technical Field

The utility model relates to the technical field of electronics, in particular to a voltage comparator.

Background

The voltage comparator has wide application in the fields of logic judgment, waveform arrangement and the like, and the traditional comparator circuit structure comprises: zero-crossing comparators, fixed voltage comparators, window comparators, hysteresis comparators, etc. The zero-crossing comparator needs to adopt a dual power supply system (positive and negative power supplies), the system is complex, and the zero-crossing comparator is not adaptive to the circuit levels of TTL or LVTTL interfaces and needs to perform logic level conversion. The fixed voltage comparator connects one end of the comparator to a fixed voltage, the other end inputs a signal to be compared, the comparison voltage is fixed, dynamic adjustment cannot be performed according to the amplitude of the input signal, the signal pulse width recovery distortion is large, the application range is narrow, and the comparator is particularly not suitable for a high-dynamic-range input scene. For example, the method is used for recovering signals on a communication link, after the signals are attenuated by a transmission link, the waveform shape change of a receiving end is large, the amplitude dynamic range is large, and if fixed comparison voltage is adopted, the waveform after recovery is seriously distorted, so that serious error codes are caused, and normal communication cannot be realized. The window comparator and the hysteresis comparator have a difference value between an upper limit trigger level and a lower limit trigger level, the difference value is hysteresis voltage, and the window comparator and the hysteresis comparator are mainly used for filtering input end interference, eliminating waveform jitter and the like. In addition, in a communication system, the existing voltage comparator generally adopts a zero-crossing comparison method, but for a unipolar communication circuit, a transmission signal has no zero point, and the setting of a decision level is difficult.

SUMMERY OF THE UTILITY MODEL

Therefore, the technical problem to be solved by the present invention is to overcome the defect in the prior art that the voltage comparator cannot realize zero-cross comparison for unipolar voltages, thereby providing a voltage comparator.

In order to achieve the purpose, the utility model provides the following technical scheme:

an embodiment of the present invention provides a voltage comparator, including: the circuit comprises a voltage division circuit, a comparison circuit, a blocking circuit and a filter circuit, wherein the first end of the voltage division circuit is grounded, and the second end of the voltage division circuit is connected with an external power supply; the first end of the comparison circuit is connected with an external power supply, the second end of the comparison circuit is connected with the third end of the voltage division circuit, the third end of the comparison circuit is connected with the fourth end of the voltage division circuit, the fourth end of the comparison circuit is grounded, and the fifth end of the comparison circuit outputs a voltage comparison result; a first end of the blocking circuit inputs unipolar voltage, and a second end of the blocking circuit is connected with a third end of the comparison circuit; and the first end of the filter circuit is grounded, and the second end of the filter circuit is connected with the third end of the voltage division circuit.

In one embodiment, the voltage divider circuit includes: the first end of the first voltage division circuit is grounded, the second end of the first voltage division circuit is connected with an external power supply, and the third end of the first voltage division circuit is respectively connected with the second end of the filter circuit and the second end of the comparison circuit; and a first end of the second voltage division circuit is connected with a third end of the first voltage division circuit, and a second end of the second voltage division circuit is respectively connected with a second end of the DC blocking circuit and a third end of the comparison circuit.

In one embodiment, the first voltage divider circuit includes: the first end of the first resistor is grounded, and the second end of the first resistor is connected with the second end of the filter circuit; and a first end of the second resistor is connected with the external power supply, and a second end of the second resistor is respectively connected with a second end of the comparison circuit, a second end of the first resistor and a first end of the second voltage division circuit.

In one embodiment, the second voltage dividing circuit includes: a third resistor; and a first end of the third resistor is respectively connected with a second end of the first resistor, a second end of the second resistor and a second end of the comparison circuit, and a second end of the third resistor is respectively connected with a second end of the blocking circuit and a third end of the comparison circuit.

In one embodiment, the comparison circuit includes: a comparator; and the positive power supply end of the comparator is connected with an external power supply, the negative power supply end of the comparator is grounded, the non-inverting input end of the comparator is respectively connected with the second end of the third resistor and the second end of the blocking circuit, and the inverting input end of the comparator is respectively connected with the second end of the first resistor, the second end of the second resistor, the first end of the third resistor and the second end of the first capacitor.

In one embodiment, the dc blocking circuit includes: a first capacitor; and the first end of the first capacitor is input with unipolar voltage, and the second end of the first capacitor is connected with the non-inverting input end of the comparator.

In one embodiment, a filter circuit includes: a second capacitor; a first end of the second capacitor is grounded, and a second end of the second capacitor is respectively connected with a second end of the first resistor, a second end of the second resistor, a first end of the third resistor and an inverted input end of the comparator; the second capacitor and the second resistor form a low-pass filter; the second capacitor and the third resistor form a low-pass filter.

In one embodiment, the voltage comparator further comprises: a fourth resistor; the first end of the comparator is connected with the second end of the first capacitor, the second end of the third resistor and the inverting input end of the comparator respectively, and the second end of the comparator is connected with an external power supply.

In one embodiment, the voltage comparator further comprises: and the power supply module is respectively connected with the second end of the voltage division circuit, the first end of the comparison circuit and the second end of the fourth resistor.

The technical scheme of the utility model has the following advantages:

according to the voltage comparator provided by the utility model, the unipolar voltage is input into the blocking circuit, the blocking circuit has a function of blocking direct current and alternating current, the blocking circuit filters out direct current signals in the unipolar voltage and outputs alternating current signals, the amplitude of the alternating current signals is +/-Vpp/2, and Vpp is the difference value of the upper peak value and the lower peak value of the alternating current signals in the unipolar voltage. The voltage divider circuit provides reference voltage for the comparison circuit, the comparison circuit takes the sum of the alternating current signal output by the blocking circuit and the reference voltage as the voltage to be compared, the comparison circuit compares the voltage to be compared with the reference voltage and finally outputs a comparison result, and the amplitude of the alternating current signal is +/-Vpp/2, so that the voltage comparator provided by the embodiment of the utility model can realize that the comparison circuit is turned over when the amplitude of the unipolar voltage is half of the amplitude of the unipolar voltage, and the function of zero-crossing comparison of the unipolar signal is realized.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

Fig. 1 is a block diagram of a specific example of a voltage comparator according to an embodiment of the present invention;

fig. 2 is a block diagram of another specific example of the voltage comparator according to the embodiment of the present invention;

fig. 3 is a block diagram of another specific example of the voltage comparator according to the embodiment of the present invention;

fig. 4 is a composition diagram of another specific example of the voltage comparator according to the embodiment of the present invention;

fig. 5 is a composition diagram of another specific example of the voltage comparator according to the embodiment of the present invention.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; the two elements may be directly connected or indirectly connected through an intermediate medium, or may be communicated with each other inside the two elements, or may be wirelessly connected or wired connected. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Furthermore, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

Examples

An embodiment of the present invention provides a voltage comparator, as shown in fig. 1, including: a voltage division circuit 1, a comparison circuit 2, a DC blocking circuit 3 and a filter circuit 4.

Specifically, as shown in fig. 1, a first end of the voltage divider circuit 1 is grounded, and a second end of the voltage divider circuit 1 is connected to an external power supply; the first end of the comparison circuit 2 is connected with an external power supply, the second end of the comparison circuit 2 is connected with the third end of the voltage division circuit 1, the third end of the comparison circuit 2 is connected with the fourth end of the voltage division circuit 1, the fourth end of the comparison circuit 2 is grounded, and the fifth end of the comparison circuit 2 outputs a voltage comparison result; a first end of the blocking circuit 3 inputs unipolar voltage, and a second end of the blocking circuit 3 is connected with a third end of the comparison circuit 2; the first end of the filter circuit 4 is grounded, and the second end of the filter circuit 4 is connected with the third end of the voltage division circuit 1.

Specifically, as shown in fig. 1, the unipolar voltage is input to the dc blocking circuit 3, and the dc blocking circuit 3 has a function of blocking dc and ac, and filters out a dc signal in the unipolar voltage to output an ac signal, where the amplitude of the ac signal is ± Vpp/2, and Vpp is a difference between upper and lower peaks of the ac signal in the unipolar voltage. The voltage divider circuit 1 provides a reference voltage for the comparator circuit 2, the comparator circuit 2 takes the sum of the alternating current signal output by the blocking circuit 3 and the reference voltage as a voltage to be compared, the comparator circuit 2 compares the voltage to be compared with the reference voltage, and finally outputs a comparison result, because the amplitude of the alternating current signal is +/-Vpp/2, the voltage comparator provided by the embodiment of the utility model can realize that the comparator circuit 2 is turned over when the amplitude of the unipolar voltage is half, and the function of zero-crossing comparison of the unipolar signal is realized.

In one embodiment, as shown in fig. 2, the voltage divider circuit 1 includes: a first voltage dividing circuit 11 and a second voltage dividing circuit 12, wherein a first end of the first voltage dividing circuit 11 is grounded, a second end of the first voltage dividing circuit 11 is connected with an external power supply, and a third end of the first voltage dividing circuit 11 is respectively connected with a second end of the filter circuit 4 and a second end of the comparison circuit 2; a first end of the second voltage-dividing circuit 12 is connected to a third end of the first voltage-dividing circuit 11, and a second end of the second voltage-dividing circuit 12 is connected to a second end of the dc blocking circuit 3 and a third end of the comparator circuit 2, respectively.

In one embodiment, as shown in fig. 3, the first voltage divider 11 includes a first resistor R1 and a second resistor R2, the second voltage divider 12 includes a third resistor R3, the comparator 2 includes a comparator U1, the dc blocking circuit 3 includes a first capacitor C1, and the filter circuit 4 includes a second capacitor C2.

Specifically, as shown in fig. 3, a first terminal of the first resistor R1 is grounded, and a second terminal of the first resistor R1 is connected to a second terminal of the filter circuit 4 (C2); a first end of the second resistor R2 is connected to the external power source, and a second end of the second resistor R2 is connected to a second end of the comparator circuit 2(U1), a second end of the first resistor R1, and a first end of the second voltage divider circuit 12(R3), respectively.

Specifically, as shown in fig. 3, a first end of the third resistor R3 is connected to a second end of the first resistor R1, a second end of the second resistor R2, and a second end of the comparison circuit 2(U1), respectively, and a second end of the third resistor R3 is connected to a second end of the dc blocking circuit 3(C1) and a third end of the comparison circuit 2(U1), respectively.

Specifically, as shown in fig. 3, the positive power supply terminal of the comparator U1 is connected to the external power supply, the negative power supply terminal of the comparator U1 is grounded, the non-inverting input terminal of the comparator U1 is connected to the second terminal of the third resistor R3 and the second terminal of the dc blocking circuit 3(C1), and the inverting input terminal of the comparator U1 is connected to the second terminal of the first resistor R1, the second terminal of the second resistor R2, the first terminal of the third resistor R3, and the second terminal of the first capacitor C1.

Specifically, as shown in fig. 3, a first terminal of the first capacitor C1 inputs a unipolar voltage, and a second terminal of the first capacitor C1 is connected to a non-inverting input terminal of the comparator U1.

Specifically, as shown in fig. 3, a first end of the second capacitor C2 is grounded, and a second end of the second capacitor C2 is connected to a second end of the first resistor R1, a second end of the second resistor R2, a first end of the third resistor R3, and an inverting input terminal of the comparator U1, respectively; the second capacitor C2 and the second resistor R2 form a low-pass filter; the second capacitor C2 and the third resistor R3 form a low-pass filter.

Specifically, as shown in fig. 3, the inverting input terminal of the comparator U1 and the first voltage dividing circuit 11 formed by the first resistor R1 and the second resistor R2 provide a dc voltage (reference voltage), and the second resistor R2 and the second capacitor C2 form a low-pass filter to filter noise interference at the inverting input terminal of the comparator U1. The positive phase input end of the comparator U1 is connected with the negative phase input end thereof through a third resistor R3, and the positive phase input end voltage Vu1+ of the comparator U1 is equal to the negative phase input end voltage Vu 1-thereof because the input impedance of the comparator U1 is extremely large.

Specifically, as shown in fig. 3, the unipolar voltage signal is input to the positive phase input terminal of the comparator U1 through the first capacitor C1, and since the first capacitor C1 has the function of isolating the dc signal and passing the ac signal, after the unipolar voltage signal passes through the first capacitor C1, the first capacitor C1 outputs the ac signal with the amplitude of ± Vpp/2, and the ac signal with the amplitude of ± Vpp/2 is superimposed with the voltage Vu1+ at the positive phase input terminal and is input to the positive phase input terminal of the comparator U1, that is, the actual input voltage at the positive phase input terminal of the comparator U1 is (Vu1+) (± Vpp/2).

Specifically, as shown in fig. 3, the unipolar voltage signal is sequentially input to the inverting input terminal of the comparator U1 through the first capacitor C1 and the third resistor R3, but since the third resistor R3 and the second capacitor C2 form a low-pass filter, the signal is filtered out at the inverting input terminal of the comparator U1, that is, the voltage at the inverting input terminal of the comparator U1 keeps Vu 1-. Since the voltage Vu1+ of the positive phase input end of the comparator U1 is equal to the voltage Vu 1-of the negative phase input end thereof, the comparator U1 compares the actual input voltage of the positive phase input end (Vu1+) + (± Vpp/2) with the voltage Vu 1-of the negative phase input end, and the comparator U1 can realize the inversion at half of the amplitude of the input signal, namely Vpp/2, and realize the function of zero-crossing comparison of unipolar signals.

Specifically, the embodiment of the utility model adopts the first resistor R1 and the second resistor R2 with the same resistance value, so as to obtain the maximum input voltage margin.

In one embodiment, as shown in fig. 4, the voltage comparator further includes: a fourth resistor R4; the first end of the fourth resistor R4 is connected to the second end of the first capacitor C1, the second end of the third resistor R3, and the inverting input terminal of the comparator U1, respectively, and the second end of the fourth resistor R4 is connected to the external power supply.

Specifically, when the fourth resistor R4 is not connected, the positive-phase input terminal voltage Vu1+ of the comparator U1 is equal to the negative-phase input terminal voltage Vu1-, and when the fourth resistor R4 is connected, the external power supply provides a current through the fourth resistor R4, and the current sequentially flows through the fourth resistor R4, the third resistor R3 and the first resistor R1 to the GND terminal, so that a voltage difference is formed between the two terminals of the third resistor R3, so that the positive-phase input terminal voltage Vu1+ of the comparator U1 is greater than the negative-phase input terminal voltage Vu1-, and the difference between Vu1+ and Vu 1-is a hysteresis voltage, and the adjustment of the hysteresis voltage can be realized by configuring the resistance value of the fourth resistor R4.

In one embodiment, as shown in fig. 5, the voltage comparator further includes: and the power module 5 is connected with the second end of the voltage division circuit 1, the first end of the comparison circuit 2 and the second end of the fourth resistor R4 respectively.

Although the present invention has been described in detail with respect to the exemplary embodiments and the advantages thereof, those skilled in the art will appreciate that various changes, substitutions and alterations can be made to the embodiments without departing from the spirit and scope of the utility model as defined by the appended claims. For other examples, one of ordinary skill in the art will readily appreciate that the order of the process steps may be varied while maintaining the scope of the present invention.

Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed, that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.

Claims

1. A voltage comparator, comprising: a voltage dividing circuit, a comparison circuit, a DC blocking circuit and a filter circuit, wherein,

the first end of the voltage division circuit is grounded, and the second end of the voltage division circuit is connected with an external power supply;

the first end of the comparison circuit is connected with an external power supply, the second end of the comparison circuit is connected with the third end of the voltage division circuit, the third end of the comparison circuit is connected with the fourth end of the voltage division circuit, the fourth end of the comparison circuit is grounded, and the fifth end of the comparison circuit outputs a voltage comparison result;

the first end of the blocking circuit inputs unipolar voltage, and the second end of the blocking circuit is connected with the third end of the comparison circuit;

and the first end of the filter circuit is grounded, and the second end of the filter circuit is connected with the third end of the voltage division circuit.

2. The voltage comparator according to claim 1, wherein the voltage dividing circuit comprises: a first voltage-dividing circuit and a second voltage-dividing circuit, wherein,

the first end of the first voltage division circuit is grounded, the second end of the first voltage division circuit is connected with an external power supply, and the third end of the first voltage division circuit is respectively connected with the second end of the filter circuit and the second end of the comparison circuit;

and a first end of the second voltage division circuit is connected with a third end of the first voltage division circuit, and a second end of the second voltage division circuit is respectively connected with a second end of the blocking circuit and a third end of the comparison circuit.

3. The voltage comparator of claim 2, wherein the first voltage divider circuit comprises: a first resistor and a second resistor, wherein,

the first end of the first resistor is grounded, and the second end of the first resistor is connected with the second end of the filter circuit;

and a first end of the second resistor is connected with an external power supply, and a second end of the second resistor is respectively connected with a second end of the comparison circuit, a second end of the first resistor and a first end of the second voltage division circuit.

4. The voltage comparator of claim 3, wherein the second voltage divider circuit comprises:

a third resistor; and a first end of the third resistor is respectively connected with a second end of the first resistor, a second end of the second resistor and a second end of the comparison circuit, and a second end of the third resistor is respectively connected with a second end of the blocking circuit and a third end of the comparison circuit.

5. The voltage comparator of claim 4, wherein the comparison circuit comprises:

a comparator; and the positive power supply end of the comparator is connected with an external power supply, the negative power supply end of the comparator is grounded, the in-phase input end of the comparator is respectively connected with the second end of the third resistor and the second end of the blocking circuit, and the reverse phase input end of the comparator is respectively connected with the second end of the first resistor, the second end of the second resistor, the first end of the third resistor and the second end of the first capacitor.

6. The voltage comparator as claimed in claim 5, wherein the dc blocking circuit comprises:

a first capacitor; the first end of the first capacitor is input with unipolar voltage, and the second end of the first capacitor is connected with the non-inverting input end of the comparator.

7. The voltage comparator of claim 6, wherein the filter circuit comprises:

a second capacitor; the first end of the second capacitor is grounded, and the second end of the second capacitor is respectively connected with the second end of the first resistor, the second end of the second resistor, the first end of the third resistor and the inverting input end of the comparator;

the second capacitor and the second resistor form a low-pass filter; the second capacitor and the third resistor form a low-pass filter.

8. The voltage comparator of claim 7, further comprising:

a fourth resistor; the first end of the comparator is connected with the second end of the first capacitor, the second end of the third resistor and the inverting input end of the comparator respectively, and the second end of the comparator is connected with an external power supply.

9. The voltage comparator of claim 8, further comprising:

and the power module is respectively connected with the second end of the voltage division circuit, the first end of the comparison circuit and the second end of the fourth resistor.