CN217113069U

CN217113069U - Circuit of simple voltage comparator

Info

Publication number: CN217113069U
Application number: CN202220646894.1U
Authority: CN
Inventors: 苏友仲
Original assignee: Fujian Morefun Electronic Technology Co ltd
Current assignee: Fujian Morefun Electronic Technology Co ltd
Priority date: 2022-03-24
Filing date: 2022-03-24
Publication date: 2022-08-02
Anticipated expiration: 2032-03-24

Abstract

The utility model provides a circuit of a simple voltage comparator, relating to the technical field of voltage comparators; the method comprises the following steps: the reference comparison circuit comprises a base electrode of an NPN triode Q1 connected with a reference voltage end, a collector electrode of an NPN triode Q1 connected with a direct-current voltage end, an emitter electrode of an NPN triode Q1 connected with one end of a resistor R1 and an emitter electrode of an NPN triode Q2, the other end of the resistor R1 is grounded, the base electrode of the NPN triode Q2 is connected with one end of a resistor R2, and the other end of the resistor R2 is connected with an input voltage end; the comparison output circuit comprises a base electrode of a PNP triode Q3 connected with a collector electrode of an NPN triode Q2, an emitting electrode of the PNP triode Q3 connected with a direct-current voltage end, and a collector electrode of the PNP triode Q3 connected with one end of a resistor R3 and an output level end. The utility model has the advantages that: the utility model discloses a simpler electronic components, like resistance, triode to the simplest design has realized voltage comparator's function, has that the circuit is retrencied, dependable performance, characteristics with low costs.

Description

Circuit of simple voltage comparator

Technical Field

The utility model relates to a voltage comparator technical field specifically relates to a circuit of simple and easy voltage comparator.

Background

The voltage comparator is a circuit for discriminating and comparing input signals, and is a basic unit circuit constituting a non-sinusoidal wave generating circuit. It compares an analog voltage signal with a reference fixed voltage, and in the vicinity of the two equal in amplitude, the output voltage will jump to output a high level or a low level correspondingly. The comparator can form a non-sine wave conversion circuit and is applied to the fields of analog and digital signal conversion and the like. Commonly used voltage comparators include single-limit comparators, hysteretic comparators, window comparators, tri-state voltage comparators, etc. It can be used in alarm circuit, automatic control circuit, measurement technique, V/F conversion circuit, A/D conversion circuit, high-speed sampling circuit, power supply voltage monitoring circuit, oscillator and voltage-controlled oscillator circuit, zero-crossing detection circuit, etc.

The existing voltage comparison method: 1. the voltage comparison is completed by adopting a special integrated chip, the main defect is high cost, the method is generally used for some application occasions with higher electrical performance requirements, and other chips also need the control participation of the MCU and occupy related resources of the MCU. In some applications without MCU, the method of integrated chip can not be adopted. 2. The comparator is formed by an operational amplifier and peripheral circuits. In the occasion with low requirements, a general operational amplifier can be used as a circuit of the comparator, but a peripheral circuit is required to be added, so that more devices are provided, the circuit structure is complex, the cost is higher, and too much circuit space is occupied.

SUMMERY OF THE UTILITY MODEL

The to-be-solved technical problem of the utility model lies in providing an easy voltage comparator's circuit, the circuit is retrencied, dependable performance, with low costs.

The utility model discloses a realize like this: a circuit for a simple voltage comparator, comprising:

a reference comparison circuit and a comparison output circuit;

the reference comparison circuit comprises a reference voltage end, an input voltage end, a direct-current voltage end, an NPN triode Q1, an NPN triode Q2, a resistor R1 and a resistor R2, wherein the base electrode of the NPN triode Q1 is connected with the reference voltage end, the collector electrode of the NPN triode Q1 is connected with the direct-current voltage end, the emitter electrode of the NPN triode Q1 is connected with one end of the resistor R1 and the emitter electrode of the NPN triode Q2, the other end of the resistor R1 is grounded, the base electrode of the NPN triode Q2 is connected with one end of the resistor R2, and the other end of the resistor R2 is connected with the input voltage end;

the comparison output circuit comprises an output level end, a PNP triode Q3, a resistor R3 and a resistor R4, the base of the PNP triode Q3 is connected with the collector of the NPN triode Q2, one end of the resistor R4 is connected, the emitter of the PNP triode Q3 is connected with the direct-current voltage end and the other end of the resistor R4, the collector of the PNP triode is connected with one end of the resistor R3 and the output level end, and the other end of the resistor R3 is grounded.

Furthermore, the comparison output circuit further comprises a resistor R5, one end of the resistor R5 is connected with the output level end, and the other end of the resistor R5 is connected with the input voltage end.

The utility model has the advantages that: the utility model discloses a simpler electronic components, like resistance, triode to the simplest design has realized voltage comparator's function, has that the circuit is retrencied, dependable performance, characteristics with low costs. The utility model discloses a circuit is the key and has arrived most specifically and has accomplished benchmark comparison voltage's mapping at NPN triode Q1 and Q2 of having utilized, accomplishes comparison voltage's output through NPN triode Q2 and PNP triode Q3 in addition. The utility model discloses a device constitutes simply, with low costs, occupies that circuit space is little, and the circuit is reliable and stable, at some simple application scenario sexual valence relative altitude.

Drawings

The invention will be further described with reference to the following examples with reference to the accompanying drawings.

Fig. 1 is a schematic diagram of a circuit of a simple voltage comparator according to the present invention.

Detailed Description

The embodiment of the utility model provides a through providing a simple and easy voltage comparator's circuit, solved among the prior art voltage comparator structure too complicated, shortcoming that design cost is high, realized that the circuit is retrencied, dependable performance, with low costs technological effect.

The embodiment of the utility model provides an in technical scheme for solving above-mentioned shortcoming, the general thinking is as follows: by adopting a simpler electronic device, the reference voltage is mapped through the NPN triodes Q1 and Q2, so that the NPN triode Q2 obtains the reference voltage compared with the input voltage; when the input voltage is greater than the reference voltage, the PNP transistor Q3 is conductive; thereby leading the PNP triode Q1 to be conducted, and the collector output of the PNP triode Q1 is high level; when the input voltage is less than the reference voltage, the NPN transistor Q2 is turned off, so that the PNP transistor Q1 is also turned off, and the collector output of the PNP transistor Q1 is at a low level; thereby completing the operation of the voltage comparator.

For better understanding of the above technical solutions, the following detailed descriptions will be provided in conjunction with the drawings and the detailed description of the embodiments.

Referring to fig. 1, a preferred embodiment of the present invention.

A circuit for a simple voltage comparator, comprising: a reference comparison circuit and a comparison output circuit; the reference comparison circuit comprises a reference voltage end, an input voltage end, a direct-current voltage end, an NPN triode Q1, an NPN triode Q2, a resistor R1 and a resistor R2, wherein the base of the NPN triode Q1 is connected with the reference voltage end, the collector of the NPN triode Q1 is connected with the direct-current voltage end, the emitter of the NPN triode Q1 is connected with one end of the resistor R1 and the emitter of the NPN triode Q2, the other end of the resistor R1 is grounded, the base of the NPN triode Q2 is connected with one end of the resistor R2, and the other end of the resistor R2 is connected with the input voltage end; the comparison output circuit comprises an output level end, a PNP triode Q3, a resistor R3 and a resistor R4, the base of the PNP triode Q3 is connected with the collector of the NPN triode Q2, one end of the resistor R4 is connected, the emitter of the PNP triode Q3 is connected with the direct-current voltage end and the other end of the resistor R4, the collector of the PNP triode is connected with one end of the resistor R3 and the output level end, and the other end of the resistor R3 is grounded.

The working principle of the reference comparison circuit is as follows: according to the characteristic that the emitter of the triode has a following effect, the voltage of a reference voltage Vref is reduced to Vbe through the voltage drop of the base and the emitter of the NPN triode Q1, a working voltage (Vref-Vbe) is provided for the resistor R1, the resistor R1 is used for setting a working current, the voltage of the emitter of the NPN triode Q1 is the same as that of the emitter of the NPN triode Q2, and the Vbe of the NPN triode Q1 is the same as that of the NPN triode Q2, so whether the NPN triode Q2 is conducted or not depends on whether the input voltage VCC _ WAVE is larger than the reference voltage Vref or not. The dc voltage terminal Vcc takes + 5V. When the input voltage VCC _ WAVE is greater than the reference voltage Vref, the NPN triode Q2 is conducted; when the input voltage VCC _ WAVE is smaller than the reference voltage Vref, the NPN triode Q2 is cut off; from the above circuit, it can be seen that the mapping of the reference voltage is completed by the NPN transistors Q1 and Q2, so that the NPN transistor Q2 obtains the reference voltage compared with the input voltage.

The working principle of the comparison output circuit is as follows: as can be appreciated from the above reference comparator circuit, when the input voltage VCC _ WAVE is greater than the reference voltage Vref, the NPN transistor Q2 is conductive; the base of the PNP transistor Q3 thereby becomes low, causing the PNP transistor Q3 to turn on, so that the output level terminal V _ OUT is high (Vcc-Vce); when the input voltage VCC _ WAVE is smaller than the reference voltage Vref, the NPN transistor Q2 is turned off, so that the base of the PNP transistor Q1 is high, the PNP transistor Q1 is also turned off, the output level terminal V _ OUT is pulled to GND through the resistor R3, and the output level terminal V _ OUT outputs low. The resistor R4 mainly prevents the PNP transistor Q1 from operating in an unstable state when it is turned off.

The comparison output circuit further comprises a resistor R5, one end of the resistor R5 is connected with the output level end, and the other end of the resistor R5 is connected with the input voltage end. The resistor R5 is used for setting return difference, and the strength of positive feedback can be adjusted by changing the resistance value of the resistor R5. The resistance of the resistor R5 is much larger than the resistance of the resistor R3.

The utility model discloses a simple and easy voltage comparator's circuit's working method: when the input voltage VCC _ WAVE is greater than the reference voltage Vref, the output level terminal V _ OUT is a high level; when the input voltage VCC _ WAVE is less than the reference voltage Vref, the output level terminal V _ OUT is low.

In the prior art, a special integrated comparator chip has the defects of high cost and inapplicability to some simple application occasions, and other chips need the participation of an MCU and occupy the resources of the MCU; in some situations without MCU or in circuits requiring direct control, it cannot be used. In addition, in a comparator circuit composed of the operational amplifier, the circuit structure is complex, the circuit space is occupied, or the cost is high. The invention adopts simpler electronic components, such as a resistor and a triode, and realizes the function of the voltage comparator by the simplest design. The design is most critical and unique in that two NPN triodes are used for finishing the mapping of reference comparison voltage, and in addition, the output of the comparison voltage is finished through the NPN and PNP triodes; the invention has the advantages of simple device structure, low cost, small occupied circuit space, stable and reliable circuit and high cost performance in some simple application occasions.

Although specific embodiments of the present invention have been described, it will be understood by those skilled in the art that the specific embodiments described are illustrative only and are not limiting upon the scope of the invention, and that equivalent modifications and variations can be made by those skilled in the art without departing from the spirit of the invention, which is to be limited only by the claims appended hereto.

Claims

1. A circuit for a simple voltage comparator, comprising:

a reference comparison circuit and a comparison output circuit;

2. The circuit of claim 1, wherein the comparison output circuit further comprises a resistor R5, one end of the resistor R5 is connected to the output level terminal, and the other end of the resistor R5 is connected to the input voltage terminal.