Level signal polarity detection circuit

Abstract

The utility model discloses a level signal polarity detection circuit. The circuit comprises a level signal input end; the zero level signal detection module is electrically connected with the level signal input end and is connected in parallel with the positive polarity level signal detection module, and the zero level signal detection module is used for detecting a zero level signal; the positive polarity level signal detection module is electrically connected with the level signal input end, and the positive polarity level signal detection module is used for detecting a positive polarity level signal; and a negative polarity level signal is detected based on the positive polarity level signal detection module and the zero level signal detection module. According to the utility model, the polarity of the level signal can be detected by using the power supply system with only a positive power supply, the circuit structure is simple, the reliability is high, the cost is low, and the level signal polarity detection accuracy can be improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to electronic circuit technical field more particularly, relate to a level signal polarity detection circuit. BACKGROUND

[0002] In electronic equipment and circuit system, accurately detecting the polarity of level signal has important significance to signal processing, system control and normal operation of equipment. For example, in communication system, need according to the polarity of signal to determine the transmission direction and format of data;In power management system, want to judge the access state of power supply according to the polarity of level signal etc. Traditional level signal polarity detection device often has problems such as complex circuit, low detection precision, slow response speed, which is difficult to meet the efficient and accurate requirements of modern electronic equipment on signal detection. And for the detection of negative level, the usual practice is to use negative power supply, in order to distinguish three levels, need to use the comparator circuit composed of operational amplifier, the circuit structure is complex, and the reliability is low, and the cost is high. Therefore, it is necessary to develop a new level signal polarity detection circuit to overcome the shortcomings of the prior art.

[0003] The information disclosed in the background section of this utility model is only intended to deepen the understanding of the general background of the utility model, and should not be regarded as acknowledging or implying in any form that the information constitutes prior art known to those skilled in the art. CONTENT OF THE UTILITY MODEL

[0004] The utility model aims at providing a level signal polarity detection circuit, which solves the problems of complex circuit, low detection precision and slow response speed of traditional level signal polarity detection device, and improves the accuracy of level signal polarity detection.

[0005] To achieve the above object, the utility model provides a level signal polarity detection circuit, which comprises:

[0006] a level signal input end;

[0007] a zero level signal detection module, which is electrically connected with the level signal input end and is connected in parallel with a positive polarity level signal detection module, and is used for detecting zero level signal;

[0008] a positive polarity level signal detection module, which is electrically connected with the level signal input end, and is used for detecting positive polarity level signal;

[0009] detecting negative polarity level signal based on the positive polarity level signal detection module and the zero level signal detection module.

[0010] Optionally, the zero level signal detection module comprises:

[0011] a full-bridge rectifier circuit, electrically connected with the level signal input end, the full-bridge rectifier circuit being grounded;

[0012] an optoelectronic coupler, electrically connected with the full-bridge rectifier circuit, the optoelectronic coupler being grounded;

[0013] a first resistor, one end of which is electrically connected with the optoelectronic coupler, and the other end of which is electrically connected with a positive pole VCC of a power supply;

[0014] a first output end, electrically connected with the optoelectronic coupler.

[0015] Optionally, the positive polarity level signal detection module comprises:

[0016] a triode, a base of which is electrically connected with the level signal input end, and an emitter of which is grounded;

[0017] a second resistor, one end of which is electrically connected with a collector of the triode, and the other end of which is electrically connected with the positive pole VCC of the power supply;

[0018] a second output end, electrically connected with the collector of the triode.

[0019] Optionally, the full-bridge rectifier circuit comprises:

[0020] a first diode, an input end of which is electrically connected with the optoelectronic coupler, and an output end of which is electrically connected with the level signal input end;

[0021] a second diode, an input end of which is electrically connected with the output end of the first diode, and an output end of which is electrically connected with the optoelectronic coupler;

[0022] a third diode, an input end of which is electrically connected with the optoelectronic coupler, and an output end of which is grounded;

[0023] a fourth diode, an input end of which is electrically connected with the output end of the third diode, and an output end of which is electrically connected with the optoelectronic coupler.

[0024] Optionally, the optoelectronic coupler comprises:

[0025] a light-emitting diode, an input end of which is electrically connected with the output end of the second diode and the output end of the fourth diode, and an output end of which is electrically connected with the input end of the first diode and the input end of the third diode;

[0026] a photoelectric triode, a collector of which is electrically connected with the resistor and the first output end, and an emitter of which is grounded.

[0027] Optionally, when the level signal received by the level signal input end is a zero level signal, the first output end outputs a low level and the second output end outputs a high level.

[0028] Optionally, when the level signal received by the level signal input end is a positive polarity level signal, the first output end outputs a high level and the second output end outputs a low level.

[0029] Optionally, when the level signal received by the level signal input end is a negative polarity level signal, the first output end outputs a high level and the second output end outputs a high level.

[0030] The utility model discloses the beneficial effect lies in: the utility model discloses a zero level signal detection module that is composed of full -bridge rectifier circuit and photoelectric coupler realizes the detection of zero level signal, realizes the detection of positive polarity level signal through the positive polarity level signal detection module that is composed of triode, and the detection of negative polarity level signal is realized to the combination of zero level signal detection module and positive polarity level signal detection module, the utility model discloses the polarity of level signal can be detected by only positive power supply power supply system, and the circuit structure is simple, and the reliability is high, and the cost is low, and the accuracy of level signal polarity detection can be realized.

[0031] The device has other characteristics and advantages that will be apparent from and / or set forth in the accompanying drawings and subsequent detailed description, which together serve to illustrate specific principles of the device. BRIEF DESCRIPTION OF DRAWINGS

[0032] The above and other objects, features and advantages of the device will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which like reference characters refer to like parts throughout the several views, and wherein the exemplary embodiments of the device are shown.

[0033] Figure 1 A schematic diagram of a level signal polarity detection circuit and a truth table according to one embodiment of the device is shown.

[0034] BRIEF DESCRIPTION OF DRAWINGS

[0035] IN, signal input end, D1, full -bridge rectifier circuit, U1, photoelectric coupler, R1, resistance, R2, resistance, Q1, triode, VCC, positive power input end, OUT1, output end, OUT2, output end. DETAILED DESCRIPTION

[0036] The utility model will be described in more detail below with reference to the drawings. Although the preferred embodiments of the utility model are shown in the drawings, it should be understood that the utility model can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the utility model more thorough and complete, and to fully convey the scope of the utility model to those skilled in the art.

[0037] According to the utility model discloses a level signal polarity detection circuit, comprising:

[0038] Level signal input end;

[0039] Zero level signal detection module, with level signal input end electricity is connected with and positive polarity level signal detection module parallel connection, zero level signal detection module is used for detecting zero level signal;

[0040] Positive polarity level signal detection module, with level signal input end electricity is connected, and positive polarity level signal detection module is used for detecting positive polarity level signal;

[0041] Based on positive polarity level signal detection module and zero level signal detection module detects negative polarity level signal.

[0042] Specifically, the utility model discloses a zero level signal detection module composed of full bridge rectifier circuit and photoelectric coupler realizes the detection of zero level signal, and the positive polarity level signal detection module composed of triode realizes the detection of positive polarity level signal, and the combination of zero level signal detection module and positive polarity level signal detection module realizes the detection of negative polarity level signal, and the utility model discloses can utilize only the power supply system of positive power supply to detect the polarity of level signal, and the circuit structure is simple, and the reliability is high, and the cost is low, and the accuracy of level signal polarity detection can be realized.

[0043] In one example, the zero level signal detection module comprises:

[0044] Full bridge rectifier circuit, with level signal input end electricity is connected, and full bridge rectifier circuit ground connection;

[0045] Photoelectric coupler, photoelectric coupler and full bridge rectifier circuit electricity is connected, and photoelectric coupler ground connection;

[0046] First resistance, one end with photoelectric coupler electricity is connected, and the other end with power supply positive pole VCC electricity is connected;

[0047] First output end, with photoelectric coupler electricity is connected.

[0048] Specifically, the zero-level signal detection module comprises a full-bridge rectifier circuit electrically connected with the level signal input end and grounded, used for rectifying the input signal; an optoelectronic coupler electrically connected with the full-bridge rectifier circuit and grounded, used for electrical isolation and signal transmission; a first resistor having one end electrically connected with the optoelectronic coupler and the other end electrically connected with the positive pole VCC of the power supply, used for current limiting; and a first output end electrically connected with the optoelectronic coupler, used for outputting the zero-level detection result signal.

[0049] In one example, the positive polarity level signal detection module comprises:

[0050] a triode, a base of the triode being electrically connected with the level signal input end, an emitter of the triode being grounded;

[0051] a second resistor having one end electrically connected with a collector of the triode and the other end electrically connected with the positive pole VCC of the power supply;

[0052] a second output end electrically connected with the collector of the triode.

[0053] Specifically, the positive polarity level signal detection module is composed of a triode, a base of the triode being electrically connected with the level signal input end, an emitter of the triode being grounded; a second resistor having one end electrically connected with a collector of the triode and the other end electrically connected with the positive pole VCC of the power supply, used for current limiting; and a second output end electrically connected with the collector of the triode, used for outputting the positive polarity level detection result signal.

[0054] In one example, the full-bridge rectifier circuit comprises:

[0055] a first diode, an input end of the first diode being electrically connected with the optoelectronic coupler, an output end of the first diode being electrically connected with the level signal input end;

[0056] a second diode, an input end of the second diode being electrically connected with the output end of the first diode, an output end of the second diode being electrically connected with the optoelectronic coupler;

[0057] a third diode, an input end of the third diode being electrically connected with the optoelectronic coupler, an output end of the third diode being grounded;

[0058] a fourth diode, an input end of the fourth diode being electrically connected with the output end of the third diode, an output end of the fourth diode being electrically connected with the optoelectronic coupler.

[0059] Specifically, the full-bridge rectifier circuit is composed of four diodes, which are usually packaged together to form a rectifier bridge module, facilitating use. The connection mode of the four diodes forms a bridge structure, specifically, the anodes of two diodes are connected together, and the cathodes of the other two diodes are connected together.

[0060] In one example, the optoelectronic coupler comprises:

[0061] a light emitting diode, an input terminal of the light emitting diode being electrically connected with an output terminal of the second diode and an output terminal of the fourth diode, and an output terminal of the light emitting diode being electrically connected with an input terminal of the first diode and an input terminal of the third diode;

[0062] a photo triode, a collector of the photo triode being electrically connected with the resistor and the first output terminal, and an emitter of the photo triode being grounded.

[0063] Specifically, the optocoupler, also known as the optical coupler or optical isolator, is an electronic component that converts an electrical signal into an optical signal and then converts the optical signal back into an electrical signal. Its main purpose is to achieve electrical isolation while transmitting signals. When there is current flowing through the light emitting diode, it will emit light. This current is usually driven by the input signal. In the level signal polarity detection circuit, when the signal output by the full-bridge rectifier circuit forms a suitable forward voltage across the light emitting diode, a current will be generated, causing the light emitting diode to emit light. For the photo triode, when light shines on its base-collector junction, it will generate photo-generated carriers. These carriers will form a current inside the triode, causing the triode to conduct. After the input signal is rectified by the full-bridge rectifier, it cannot be grounded with the detection circuit, so it can only be detected by the optocoupler. The optocoupler is an isolator device, and the input and output can not be grounded. The optocoupler can only distinguish between zero levels, and cannot distinguish between positive and negative levels. The full-bridge rectifier circuit can convert positive and negative polarity signals into unidirectional current signals to drive the optocoupler. At this time, the first output terminal is at a low level. If the input of the full-bridge rectifier circuit is a zero-level signal, the optocoupler has no current, and the first output terminal is at a high level.

[0064] In one example, when the level signal received by the level signal input terminal is a zero-level signal, the first output terminal outputs a low level, and the second output terminal outputs a high level.

[0065] Specifically, when the level signal received by the level signal input terminal is a zero-level signal, the full-bridge rectifier circuit processes the zero-level signal, the light emitting diode in the optocoupler does not emit light, and the photo triode is cut off. The first output terminal outputs a low level. At the same time, since the input is a zero-level signal, the triode is cut off, and the second output terminal outputs a high level.

[0066] In one example, when the level signal received by the level signal input terminal is a positive polarity level signal, the first output terminal outputs a high level, and the second output terminal outputs a low level.

[0067] Specifically, when the input signal receives a positive level signal, the transistor conducts, and the second output terminal outputs a low level. At this time, the full-bridge rectifier circuit causes the LED in the optocoupler to emit light, the phototransistor to conduct, and the first output terminal outputs a high level.

[0068] In one example, when the level signal received at the level signal input terminal is a negative polarity level signal, the first output terminal outputs a high level, and the second output terminal outputs a high level.

[0069] Specifically, when the input signal is a negative signal, the transistor is cut off, and the second output terminal outputs a high level. Under the action of the full-bridge rectifier circuit, the LED in the optocoupler emits light, the phototransistor conducts, and the first output terminal outputs a high level. By monitoring and judging the level states of the first and second output terminals, the polarity of the input signal can be accurately determined.

[0070] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the present invention. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0071] Example:

[0072] like Figure 1 As shown, this embodiment provides a level signal polarity detection circuit, including:

[0073] The level signal input end IN, the full-bridge rectifier circuit D1 is electrically connected with the level signal input end IN, and the full-bridge rectifier circuit D1 is grounded; the photoelectric coupler U1 is electrically connected with the full-bridge rectifier circuit, and the photoelectric coupler U1 is grounded; the resistor R1 is electrically connected with the photoelectric coupler U1 at one end and is electrically connected with the positive power supply input end VCC at the other end; the output end OUT1 is electrically connected with the photoelectric coupler U1. The triode Q1 is electrically connected with the level signal input end IN at the base, and the triode Q1 is grounded at the emitter; the resistor R2 is electrically connected with the triode Q1 at one end and is electrically connected with the positive power supply input end VCC at one end; the output end OUT2 is electrically connected with the triode Q1 at the collector. The full-bridge rectifier circuit D1 comprises: the first diode, the input end of the first diode is electrically connected with the photoelectric coupler U1, and the output end of the first diode is electrically connected with the level signal input end IN; the second diode, the input end of the second diode is electrically connected with the output end of the first diode, and the output end of the second diode is electrically connected with the photoelectric coupler U1; the third diode, the input end of the third diode is electrically connected with the photoelectric coupler U1, and the output end of the third diode is grounded; the fourth diode, the input end of the fourth diode is electrically connected with the output end of the third diode, and the output end of the fourth diode is electrically connected with the photoelectric coupler U1. The photoelectric coupler U1 comprises: the light emitting diode, the input end of the light emitting diode is electrically connected with the output end of the second diode and the output end of the fourth diode, and the output end of the light emitting diode is electrically connected with the input end of the first diode and the input end of the third diode; the light-sensitive triode, the collector of the light-sensitive triode is electrically connected with the resistor and the output end OUT1, and the emitter of the light-sensitive triode is grounded. As shown in Figure 1 When the level signal received by the level signal input end IN is a zero level signal, after the full-bridge rectifier circuit D1 processes the zero level signal, the light emitting diode in the photoelectric coupler U1 does not emit light, the light-sensitive triode Q1 is cut off, and the output end OUT1 outputs a low level. At the same time, since the input is zero level, the triode Q1 is cut off, and the output end OUT2 outputs a high level. When the level signal received by the level signal input end IN is a positive polarity level signal, the triode Q1 is turned on, and the output end OUT2 outputs a low level. At this time, the full-bridge rectifier circuit D1 makes the light emitting diode in the photoelectric coupler U1 emit light, the light-sensitive triode Q1 is turned on, and the output end OUT1 outputs a high level. When the level signal received by the level signal input end IN is a negative polarity level signal, the triode Q1 is cut off, and the output end OUT2 outputs a high level. Under the action of the full-bridge rectifier circuit D1, the light emitting diode in the photoelectric coupler U1 emits light, the light-sensitive triode Q1 is turned on, and the output end OUT1 outputs a high level. By monitoring and judging the level state of the output end OUT1 and the output end OUT2, the polarity of the input level signal can be accurately determined.

[0074] The above has described various embodiments of the present application, the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A level signal polarity detection circuit, characterized by, include: Level signal input terminal; A zero-level signal detection module is electrically connected to the level signal input terminal and is connected in parallel with the positive polarity level signal detection module. The zero-level signal detection module is used to detect zero-level signals. A positive polarity level signal detection module is electrically connected to the level signal input terminal, and the positive polarity level signal detection module is used to detect positive polarity level signals; The negative polarity level signal is detected based on the positive polarity level signal detection module and the zero polarity level signal detection module.

2. The level signal polarity detection circuit according to claim 1, characterized by, The zero-level signal detection module includes: A full-bridge rectifier circuit is electrically connected to the level signal input terminal, and the full-bridge rectifier circuit is grounded; An optocoupler, which is electrically connected to the full-bridge rectifier circuit, is grounded; The first resistor has one end electrically connected to the optocoupler and the other end electrically connected to the positive terminal VCC of the power supply. The first output terminal is electrically connected to the optocoupler.

3. The level signal polarity detection circuit according to claim 2, characterized by, The positive polarity level signal detection module includes: The transistor has its base electrically connected to the level signal input terminal and its emitter grounded. The second resistor has one end electrically connected to the collector of the transistor and the other end electrically connected to the positive terminal VCC of the power supply. The second output terminal is electrically connected to the collector of the transistor.

4. The level signal polarity detection circuit according to claim 3, characterized by, The full-bridge rectifier circuit includes: A first diode, the input terminal of which is electrically connected to the optocoupler, and the output terminal of which is electrically connected to the level signal input terminal; The second diode has its input terminal electrically connected to the output terminal of the first diode, and its output terminal electrically connected to the optocoupler. The third diode has its input terminal electrically connected to the optocoupler and its output terminal grounded. The fourth diode has its input terminal electrically connected to the output terminal of the third diode, and its output terminal electrically connected to the optocoupler.

5. The level signal polarity detection circuit according to claim 4, characterized by The optocoupler includes: A light-emitting diode (LED), wherein the input terminal of the LED is electrically connected to the output terminal of the second diode and the output terminal of the fourth diode, and the output terminal of the LED is electrically connected to the input terminal of the first diode and the input terminal of the third diode; A phototransistor, wherein the collector of the phototransistor is electrically connected to the resistor and the first output terminal, and the emitter of the phototransistor is grounded.

6. The level signal polarity detection circuit according to claim 5, characterized by When the level signal received at the level signal input terminal is a zero level signal, the first output terminal outputs a low level and the second output terminal outputs a high level.

7. The level signal polarity detection circuit according to claim 6, characterized by, When the level signal received at the level signal input terminal is a positive level signal, the first output terminal outputs a high level and the second output terminal outputs a low level.

8. The level signal polarity detection circuit according to claim 7, characterized by, When the level signal received at the level signal input terminal is a negative polarity level signal, the first output terminal outputs a high level and the second output terminal outputs a high level.

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