CN219512320U

CN219512320U - Zero-crossing detection circuit and electrical equipment

Info

Publication number: CN219512320U
Application number: CN202320556852.3U
Authority: CN
Inventors: 霍兆镜
Original assignee: GD Midea Air Conditioning Equipment Co Ltd; Guangzhou Hualing Refrigeration Equipment Co Ltd
Current assignee: GD Midea Air Conditioning Equipment Co Ltd; Guangzhou Hualing Refrigeration Equipment Co Ltd
Priority date: 2023-03-20
Filing date: 2023-03-20
Publication date: 2023-08-11
Anticipated expiration: 2033-03-20

Abstract

The utility model discloses a zero-crossing detection circuit and electrical equipment, wherein the zero-crossing detection circuit comprises an acquisition module, a switch unit and a zero-crossing detection output unit; the acquisition module comprises a constant current unit and a voltage stabilizing unit which are sequentially connected, and the acquisition module is connected with two ends of an alternating current power supply to be detected; the zero-crossing detection output unit comprises a first connecting end, a second connecting end and a zero-crossing detection output end, wherein the first connecting end is connected with a first direct current power supply, the second connecting end is connected with a first end of the switch unit, the second end of the switch unit is connected with the first direct current power supply, and a third end of the switch unit is connected with a second end of the constant current unit; the zero-crossing detection output end outputs a zero-crossing detection signal under the condition that the on-off state of the switch unit changes. According to the zero-crossing detection circuit in the technical scheme of the embodiment, the zero-crossing signal detection function can be realized, and meanwhile, the energy consumption generated in the zero-crossing detection process is effectively reduced through the functions of the constant current unit and the voltage stabilizing unit.

Description

Zero-crossing detection circuit and electrical equipment

Technical Field

The utility model relates to the technical field of circuits, in particular to a zero-crossing detection circuit and electrical equipment.

Background

At present, the technical scheme of zero-crossing detection of electrical equipment mainly adopts a voltage dividing resistor to realize voltage division of the voltage of an alternating current input power supply and utilizes an optocoupler switching tube to realize isolation detection, but the technical scheme adopts the alternating current input power supply, so that in actual use, the proportion of the power consumed by zero-crossing detection to the standby power of an energy-saving electrical equipment exceeds 20%, and the energy consumption requirements of the high-efficiency and low-standby power consumption electrical equipment cannot be met.

Disclosure of Invention

The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

The embodiment of the utility model provides a zero-crossing detection circuit and electrical equipment, which can effectively reduce energy consumption generated in the zero-crossing detection process while realizing the function of detecting a zero-crossing signal.

An embodiment of a first aspect of the present utility model provides a zero-crossing detection circuit, including an acquisition module, a switching unit, and a zero-crossing detection output unit;

the acquisition module comprises a constant current unit and a voltage stabilizing unit, wherein the first end of the constant current unit is connected with the first end of an alternating current power supply to be detected, the second end of the constant current unit is connected with the first end of the voltage stabilizing unit, and the second end of the voltage stabilizing unit is connected with the second end of the alternating current power supply to be detected;

The zero-crossing detection output unit comprises a first connecting end, a second connecting end and a zero-crossing detection output end, wherein the first connecting end is connected with a first end of a first direct current power supply, and the second connecting end is connected with a first end of the switch unit;

the second end of the switch unit is connected with the second end of the first direct current power supply, the switch unit further comprises a third end for controlling the on-off of the switch unit, and the third end of the switch unit is connected with the second end of the constant current unit;

and the zero-crossing detection output end outputs a zero-crossing detection signal under the condition that the on-off state of the switch unit changes.

The zero-crossing detection circuit according to the embodiment of the first aspect of the utility model has at least the following beneficial effects: in the zero-crossing detection process, the direction of an electric signal output by the alternating current power supply to be detected changes, so that the voltage at the connecting end of the constant current unit and the voltage stabilizing unit in the acquisition module changes positively and negatively, and then the voltage input to the third end of the switch unit changes positively and negatively, so that the switch unit is subjected to on-off phenomenon, and the zero-crossing detection signal output by the zero-crossing detection output end can reflect the change of the direction of the electric signal output by the alternating current power supply to be detected. In the technical scheme of the embodiment, the constant current unit and the voltage stabilizing unit in the acquisition module convert the electric signal output by the alternating current power supply to be detected, so that the voltage output by the alternating current power supply to be detected can be adjusted to a voltage value meeting the requirement of the third end of the switching unit with low power consumption, and the energy consumption generated in the zero-crossing detection process can be effectively reduced. The zero-crossing detection circuit can realize the function of detecting zero-crossing signals and effectively reduce the energy consumption generated in the zero-crossing detection process through the functions of the constant current unit and the voltage stabilizing unit.

In some embodiments, the constant current unit includes an X-capacitor discharge unit.

In some embodiments, the constant current unit further includes a first resistor and a second resistor, one end of the first resistor is connected to a first end of the ac power source to be detected, the other end of the first resistor is connected to a first end of the X capacitor discharge unit, one end of the second resistor is connected to a second end of the X capacitor discharge unit, the other end of the second resistor is connected to a first pole of the voltage stabilizing unit, a second pole of the voltage stabilizing unit is connected to a second end of the ac power source to be detected, and the second end is an end corresponding to the first end of the X capacitor discharge unit.

In some embodiments, the voltage dividing unit is used for dividing the voltage at the connection part of the constant current unit and the voltage stabilizing unit, so that the divided voltage is input to the third terminal of the switch unit.

In some embodiments, the voltage dividing unit includes a first voltage dividing resistor and a second voltage dividing resistor;

one end of the first voltage dividing resistor is connected with the second end of the X capacitor discharging unit, and the other end of the first voltage dividing resistor is connected with the third end of the switch unit;

one end of the second voltage dividing resistor is connected with the third end of the switch unit, and the other end of the second voltage dividing resistor is connected with the second end of the switch unit.

In an embodiment, the zero-crossing detection output unit includes a photosensitive switch unit and a third resistor, and a first light-emitting end of the photosensitive switch unit is a first connection end of the zero-crossing detection output unit;

when the voltage of the first end of the first direct current power supply is lower than that of the second end, the second end of the switch unit is connected with the first direct current power supply, the first end of the switch unit is connected with the second light-emitting end of the photosensitive switch unit through the third resistor, the first electrode of the voltage stabilizing unit is positive, and the second electrode of the voltage stabilizing unit is negative;

or alternatively, the process may be performed,

and under the condition that the voltage of the first end of the first direct current power supply is higher than that of the second end, the second end of the switch unit is grounded, the first end of the switch unit is connected with the second light-emitting end of the photosensitive switch unit through the third resistor, the first electrode of the voltage stabilizing unit is a negative electrode, and the second electrode of the voltage stabilizing unit is a positive electrode.

In some embodiments, the circuit further comprises a second direct current power supply, a fourth resistor, a fifth resistor and a first capacitor, wherein the first signal output end of the photosensitive switch unit is connected with the first end of the second direct current power supply, the first signal output end of the photosensitive switch unit is connected with the second end of the second direct current power supply through the fourth resistor and the first capacitor, the second signal output end of the photosensitive switch unit is connected to the second end of the second direct current power supply through the fifth resistor, and the connection ends of the fourth resistor and the first capacitor are the zero-crossing detection output ends.

In some embodiments, the zero-crossing detection output unit includes a sixth resistor, one end of the sixth resistor is a first connection end of the zero-crossing detection output unit, the other end is a second connection end of the zero-crossing detection output unit, and the second connection end of the zero-crossing detection output unit is the zero-crossing detection output end.

In some embodiments, the device further comprises a second capacitor, one end of the second capacitor is connected with the first end of the alternating current power supply to be detected, and the other end of the second capacitor is connected with the second end of the alternating current power supply to be detected.

In some embodiments, the device further comprises a first rectifying unit, a voltage transformation unit, a second rectifying unit and a third rectifying unit, wherein a first input end of the rectifying unit is connected with a first end of the alternating current power supply to be detected, a second input end of the rectifying unit is connected with a second end of the alternating current power supply to be detected, a first output end of the rectifying unit is connected with a first input end of the voltage transformation unit, a second output end of the rectifying unit is connected with a second input end of the voltage transformation unit, a first output end and a second output end of the voltage transformation unit are respectively connected with two ends of the second rectifying unit to form the first direct current power supply, and a third output end and a fourth output end of the voltage transformation unit are respectively connected with two ends of the third rectifying unit to form the second direct current power supply.

An embodiment of the second aspect of the present utility model provides an electrical device comprising the zero crossing detection circuit of the first aspect.

Additional features and advantages of the utility model will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the utility model. The objectives and other advantages of the utility model will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Drawings

FIG. 1 is a schematic diagram of a zero crossing detection circuit providing one embodiment of the present utility model;

FIG. 2 is a schematic diagram of a zero crossing detection circuit providing another embodiment of the present utility model;

FIG. 3 is a schematic diagram of a zero crossing detection circuit providing another embodiment of the present utility model;

FIG. 4 is a schematic diagram of a zero crossing detection circuit providing another embodiment of the present utility model;

FIG. 5 is a schematic diagram of a zero crossing detection circuit providing another embodiment of the present utility model;

FIG. 6 is a schematic diagram providing a power supply circuit for use with the zero crossing detection circuit of FIG. 5 for an embodiment of the present utility model;

FIG. 7 is a schematic diagram of a zero crossing detection circuit providing another embodiment of the present utility model;

Fig. 8 is a schematic diagram of a power supply circuit applied to the zero-crossing detection circuit of fig. 7, provided for an embodiment of the present utility model.

Detailed Description

The present utility model will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present utility model more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the utility model. Furthermore, the described features, operations, or characteristics of the description may be combined in any suitable manner in various embodiments. Also, various steps or acts in the method descriptions may be interchanged or modified in a manner apparent to those of ordinary skill in the art. Thus, the various orders in the description and drawings are for clarity of description of only certain embodiments, and are not meant to be required orders unless otherwise indicated.

In the description of the present utility model, a number means one or more, a number means two or more, and greater than, less than, exceeding, etc. are understood to not include the present number, and above, below, within, etc. are understood to include the present number. The description of the first and second is for the purpose of distinguishing between technical features only and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.

The numbering of the components itself, e.g. "first", "second", etc., is used herein merely to distinguish between the described objects and does not have any sequential or technical meaning. The term "coupled" as used herein includes both direct and indirect coupling (coupling), unless otherwise indicated.

In the description of the present utility model, unless explicitly defined otherwise, terms such as arrangement, installation, connection, etc. should be construed broadly and the specific meaning of the terms in the present utility model can be reasonably determined by a person skilled in the art in combination with the specific contents of the technical scheme.

At present, the technical scheme of zero-crossing detection of electrical equipment mainly adopts a voltage dividing resistor to realize voltage division of the voltage of an alternating current input power supply and utilizes an optocoupler switching tube to realize isolation detection, but the technical scheme adopts the alternating current input power supply, so that in actual use, the proportion of the power consumed by zero-crossing detection to the standby power of an energy-saving electrical equipment exceeds 20%, and the energy consumption requirements of the high-efficiency and low-standby power consumption electrical equipment cannot be met. For example: the voltage division is realized on the alternating current input voltage in the form of a voltage dividing resistor, the isolation detection is realized by utilizing an optocoupler, the working current of the optocoupler is at least more than 1mA, if the input voltage of the alternating current input voltage is 220V, the power consumed on the voltage dividing resistor is 0.22W, the standby power of an energy-saving electrical appliance is required to be realized under 1W, the power consumed on the voltage dividing resistor is at least up to 22%, and the energy consumption requirements of high-efficiency and low-standby power consumption electrical appliances cannot be met.

Based on the above situation, the embodiment of the utility model provides a zero-crossing detection circuit and electrical equipment, wherein the zero-crossing detection circuit comprises an acquisition module, a switch unit and a zero-crossing detection output unit; the acquisition module comprises a constant current unit and a voltage stabilizing unit, wherein the first end of the constant current unit is connected with the first end of the alternating current power supply to be detected, the second end of the constant current unit is connected with the first end of the voltage stabilizing unit, and the second end of the voltage stabilizing unit is connected with the second end of the alternating current power supply to be detected; the zero-crossing detection output unit comprises a first connecting end, a second connecting end and a zero-crossing detection output end, wherein the first connecting end is connected with the first end of the first direct current power supply, and the second connecting end is connected with the first end of the switch unit; the second end of the switch unit is connected with the second end of the first direct current power supply, the switch unit further comprises a third end for controlling the on-off of the switch unit, and the third end of the switch unit is connected with the second end of the constant current unit; the zero-crossing detection output end outputs a zero-crossing detection signal under the condition that the on-off state of the switch unit changes.

In the technical scheme of the embodiment, in the process of zero-crossing detection, the direction of the electric signal output by the alternating current power supply to be detected changes, so that the voltage at the connecting end of the constant current unit and the voltage stabilizing unit in the acquisition module changes positively and negatively, and then the voltage input to the third end of the switch unit changes positively and negatively, so that the switch unit is turned on and off, and the zero-crossing detection signal output by the zero-crossing detection output end can reflect the change of the direction of the electric signal output by the alternating current power supply to be detected. In the technical scheme of the embodiment, the constant current unit and the voltage stabilizing unit in the acquisition module convert the electric signal output by the alternating current power supply to be detected, so that the voltage output by the alternating current power supply to be detected can be adjusted to a voltage value meeting the requirement of the third end of the switching unit with low power consumption, and the energy consumption generated in the zero-crossing detection process can be effectively reduced. The zero-crossing detection circuit can realize the function of detecting zero-crossing signals and effectively reduce the energy consumption generated in the zero-crossing detection process through the functions of the constant current unit and the voltage stabilizing unit.

Embodiments of the present utility model will be further described below with reference to the accompanying drawings.

As shown in fig. 1, fig. 1 is a schematic diagram of a zero-crossing detection circuit according to an embodiment of the present utility model. The zero-crossing detection circuit can be applied to various electrical equipment, such as an air conditioner, a refrigerator, and the like, and the embodiment is not particularly limited. The zero-crossing detection circuit is used for detecting and detecting the ac power supply 110, and the zero-crossing detection circuit includes an acquisition module 120, a switching unit 130 and a zero-crossing detection output unit 140, where the ac power supply 110 to be detected is used for supplying power to electrical equipment, for example: the alternating current power supply 110 to be detected can be a 220V power supply; for another example, the ac power source 110 to be detected may be a 110V power source; the acquisition module 120 comprises a voltage stabilizing unit 122 and a constant current unit 121, wherein a first end of the constant current unit 121 is connected with a first end of the alternating current power supply 110 to be detected, a second end of the constant current unit 121 is connected with a first end of the voltage stabilizing unit 122, and a second end of the voltage stabilizing unit 122 is connected with a second end of the alternating current power supply 110 to be detected; the zero-crossing detection output unit 140 includes a first connection terminal, a second connection terminal, and a zero-crossing detection output terminal OUT, the second connection terminal is connected to the first terminal of the switching unit 130, and the first connection terminal is connected to the first direct current power VCC 1; the second end of the switch unit 130 is connected to the second end of the first direct current power supply VCC1, the switch unit 130 further comprises a third end for controlling the on-off of the switch unit 130, the third end of the switch unit 130 is connected to the second end of the constant current unit 121, and the third end of the switch unit 130 is used for determining the on-off between the first end and the second end of the switch unit 130 based on the voltage at the junction between the voltage stabilizing unit 122 and the constant current unit 121, so that the first direct current power supply VCC1 supplies power to the zero-crossing detection output unit 140; the zero-crossing detection output terminal OUT outputs a zero-crossing detection signal in the case of the on-off variation of the switching unit 130. Based on the technical solution of the present embodiment, the zero-crossing detection signal output by the zero-crossing detection output terminal OUT can reflect the electrical switching signal of the ac power supply 110 to be detected, where the zero-crossing detection output terminal OUT outputs a low level when the switching unit 130 is turned on, and the zero-crossing detection output terminal OUT outputs a high level when the switching unit 130 is turned off.

In the process of zero-crossing detection, the voltage at the connection end of the constant current unit 121 and the voltage stabilizing unit 122 in the collection module 120 changes positively and negatively according to the direction of the electric signal output by the ac power supply 110 to be detected, so that the voltage input to the third end of the switch unit 130 changes positively and negatively, and the on-off phenomenon occurs between the first end and the second end of the switch unit 130, so that the zero-crossing detection signal output by the zero-crossing detection output end OUT can reflect the change of the direction of the electric signal output by the ac power supply 110 to be detected. In addition, in the operation of collecting the electrical signal output by the ac power source 110 to be detected by the collecting module 120, the voltage output by the ac power source 110 to be detected can be adjusted to a voltage value meeting the requirement of the third terminal of the switching unit 130 with low power consumption by the action of the constant current unit 121 and the voltage stabilizing unit 122, so that the energy consumption generated in the zero-crossing detection process can be effectively reduced. Namely, by the zero-crossing detection circuit of the technical scheme of the embodiment, the function of detecting the zero-crossing signal can be realized, and the energy consumption generated in the zero-crossing detection process can be effectively reduced by the action of the constant current unit 121 and the voltage stabilizing unit 122.

It should be noted that, the voltage stabilizing unit 122 may be a voltage stabilizing diode, or may be other electrical components with voltage stabilizing capability, or may be other sub-circuits with voltage stabilizing capability; when the voltage stabilizing unit 122 is a voltage stabilizing diode, the voltage stabilizing diode can be used by utilizing the phenomenon that the current of the PN junction reverse breakdown state, namely the zener breakdown state, can be changed in a large range and the voltage is basically unchanged.

It should be noted that, the constant current unit 121 may include an X capacitor discharge unit, for example, may be an X capacitor discharge device, or may be an X capacitor discharge chip X1, where when the ac power supply 110 is to be detected, the X capacitor discharge unit may implement loss of less than 5mW, and may implement ac power supply voltage detection with ultra-low input power.

It should be noted that, the zero-crossing detection output unit 140 may include a combination of the photosensitive switch unit 210 and a resistor, or may be a resistor, which is not specifically limited in this embodiment.

It should be noted that the photosensitive switch unit 210 may include a phototransistor or may include a photodiode, which is not particularly limited in this embodiment.

Referring to fig. 2, a second capacitor C2 may be further connected to the output ends at two ends of the ac power source 110 to be detected, one end of the second capacitor C2 is connected to the first end of the ac power source 110 to be detected, the other end of the second capacitor C2 is connected to the second end of the ac power source 110 to be detected, the second capacitor C2 may be set as an X capacitor, and the differential mode interference may be effectively eliminated by connecting the second capacitor C2 to the output ends at two ends of the ac power source 110 to be detected, and the function of releasing the residual charge on the X capacitor after the ac power source 110 to be detected is powered off may be realized.

Note that, the switching unit 130 may be a MOS transistor, or may be a triode, or may be a relay, or may be other switching devices, which is not specifically limited in this embodiment.

Note that, in the case where the switch unit 130 is a MOS transistor, it may be an NMOS transistor or a PMOS transistor, which is not particularly limited in this embodiment. It is understood that when the switching unit 130 may be an NMOS transistor, it may also be an enhanced NMOS transistor, or it may be a depletion NMOS transistor, which is not particularly limited in this embodiment. It is further understood that when the switch unit 130 may be a PMOS transistor, it may also be an enhanced PMOS transistor, or may be a depletion PMOS transistor, which is not specifically limited in this embodiment. For example, when the switch unit 130 is an NMOS transistor, the third terminal of the switch unit 130 is a G pole, the first terminal is a D pole, and the second terminal is an S pole. The third terminal, the first terminal, and the second terminal may be provided according to the actual situation of the switching unit 130, and the present embodiment is not particularly limited.

The first dc power VCC1 may be a power supply obtained by detecting the voltage drop of the ac power supply 110 by the voltage transformation unit, or may be an independent power supply, and the present embodiment is not limited thereto.

As shown in fig. 3, fig. 3 is a schematic diagram of a zero-crossing detection circuit according to another embodiment of the present utility model. In some alternative embodiments, the constant current unit 121 includes an X capacitor discharge chip X1, a first resistor R1, and a second resistor R2, where a first end of the ac power supply to be detected 110 is connected to one end of the first resistor R1, a first end of the X capacitor discharge chip X1 is connected to the other end of the first resistor R1, a second end of the X capacitor discharge chip X1 is connected to one end of the second resistor R2, a first pole of the zener diode DZ4 is connected to the other end of the second resistor R2, a second end of the ac power supply to be detected 110 is connected to a first pole of the zener diode DZ4, and a second end of the X capacitor discharge chip X1 is a corresponding end of the first end of the X capacitor discharge chip X1. Under the condition that the ac power supply 110 to be detected inputs voltage, the maximum working current is limited by the capacitive reactance generated by the X capacitor discharge chip X1 at the frequency of switching the direction of the output electric signal of the ac power supply 110 to be detected, and the power consumption generated by the constant current unit 121 can be lower than 5mW through the cooperation of the X capacitor discharge chip X1 and the second resistor R2.

In some alternative embodiments, a voltage dividing unit is disposed between the collection module 120 and the switching unit 130, and the voltage dividing unit is configured to divide the voltage at the connection between the constant current unit 121 and the voltage stabilizing unit 122, so as to input the divided voltage to the third terminal of the switching unit 130. Specifically, the voltage dividing unit includes a first voltage dividing resistor R11 and a second voltage dividing resistor R12, the second end of the X capacitor discharge chip X1 is connected to one end of the first voltage dividing resistor R11, the third end of the switch unit 130 is connected to the other end of the first voltage dividing resistor R11, the third end of the switch unit 130 is connected to one end of the second voltage dividing resistor R12, and the second end of the switch unit 130 is connected to the other end of the second voltage dividing resistor R12. The voltage input to the third terminal of the switching unit 130 is determined by the resistance value of the first voltage dividing resistor R11 and the resistance value of the second voltage dividing resistor R12, so that the voltage value input to the third terminal of the switching unit 130 can be better controlled, and the problem of controlling the voltage value input to the third terminal of the switching unit 130 to be too large can be prevented.

In some alternative embodiments, the zero-crossing detection output unit 140 may include a third resistor R3 and a photo-switching unit 210, and the first light emitting end of the photo-switching unit 210 is the first connection end of the zero-crossing detection output unit 140. For example: when the voltage of the first end of the first direct current power VCC1 is lower than the voltage of the second end, the first end of the switching unit 130 is connected to the second light emitting end of the photosensitive switching unit 210 through the third resistor R3, and the first pole of the voltage stabilizing unit 122 is positive, and the second pole of the voltage stabilizing unit 122 is negative. Also for example: when the voltage at the first end of the first dc power supply VCC1 is higher than the voltage at the second end, the first end of the switching unit 130 is connected to the second light-emitting end of the photosensitive switching unit 210 through the third resistor R3, the first electrode of the voltage stabilizing unit 122 is a negative electrode, and the second electrode of the voltage stabilizing unit 122 is a positive electrode. The on-off of the switch unit 130 can make the photosensitive switch unit 210 on-off, so that the direction of the output electric signal can be reflected to change through the on-off condition of the photosensitive switch unit 210, that is, the zero-crossing detection signal output by the zero detection output end OUT can reflect the electric switching signal of the ac power supply 110 to be detected.

In the case of the photoswitch unit 210, the zero-crossing detection circuit further includes a second dc power supply VCC2, a fourth resistor R4, a first capacitor C1, and a fifth resistor R5, the first signal output terminal of the photoswitch unit 210 is connected to the first terminal of the second dc power supply VCC2, the second signal output terminal of the photoswitch unit 210 is connected to the second terminal of the second dc power supply through the fifth resistor R5, the first signal output terminal of the photoswitch unit 210 is connected to the second terminal of the second dc power supply through the fourth resistor R4 and the first capacitor C1, and the connection terminal of the first capacitor C1 and the fourth resistor R4 is the zero-crossing detection output terminal OUT. By providing the first capacitor C1 at the output terminal of the photosensitive switching unit 210, the signal output from the output terminal of the photosensitive switching unit 210 can be filtered, so that the zero crossing detection signal output from the zero crossing detection output terminal OUT is better.

The second dc power VCC2 may be a power obtained by detecting the voltage drop of the ac power 110 by the voltage transformation unit, or may be an independent power, which is not particularly limited in this embodiment.

As shown in fig. 4, fig. 4 is a schematic diagram of a zero-crossing detection circuit according to another embodiment of the present utility model. In some alternative embodiments, based on the structure of fig. 2, the zero-crossing detection output unit 140 is replaced by a sixth resistor R6, where one end of the sixth resistor R6 is a first connection end of the zero-crossing detection output unit 140, and the other end is a second connection end of the zero-crossing detection output unit 140, and the second connection end of the zero-crossing detection output unit 140 is a zero-crossing detection output end OUT. In the technical solution of this embodiment, the switching of the electrical signal of the ac power source 110 to be detected can be directly reflected by the on-off of the switch unit 130, so as to achieve the purpose of zero-crossing detection.

The structure and the operation principle of the zero-crossing detection circuit provided by the embodiment of the utility model are fully described below with some specific examples.

Referring to fig. 5, fig. 5 is a schematic diagram of a zero crossing detection circuit according to another embodiment of the present utility model. The zero-crossing detection circuit in this embodiment is configured to detect a zero-crossing condition of the ac power supply 110 to be detected, and includes an acquisition module 120, a voltage division unit, a photosensitive switch unit 210, a third resistor R3, a switch unit 130, a first capacitor C1, a second capacitor C2, a fourth resistor R4, a fifth resistor R5, and a zero-crossing detection output terminal OUT; the to-be-detected alternating current power supply 110 is used for supplying power to the electrical equipment, the to-be-detected alternating current power supply 110 is provided with a first end and a second end, one end of the second capacitor C2 is connected with the first end of the to-be-detected alternating current power supply 110, and the other end of the second capacitor C2 is connected with the second end of the to-be-detected alternating current power supply 110; the acquisition module 120 comprises a constant current unit 121 and a voltage stabilizing diode DZ4 (voltage stabilizing unit 122) connected with the constant current unit 121, and the constant current unit 121 comprises an X capacitor discharge chip X1, a first resistor R1 and a second resistor R2; one end of the first resistor R1 is connected with a first end of the alternating current power supply 110 to be detected, the other end of the first resistor R1 is connected with a first end of the X capacitor discharge chip X1, one end of the second resistor R2 is connected with a second end of the X capacitor discharge chip X1, the other end of the second resistor R2 is connected with a first pole of the voltage stabilizing unit 122, a second pole of the voltage stabilizing unit 122 is connected with a second end of the alternating current power supply 110 to be detected, and the second end is a corresponding end of the first end of the X capacitor discharge chip X1; the voltage dividing unit comprises a first voltage dividing resistor R11 and a second voltage dividing resistor R12, wherein one end of the first voltage dividing resistor R11 is connected with the second end of the X capacitor discharge chip X1, the other end of the first voltage dividing resistor R11 is connected with the third end of the switch unit 130, one end of the second voltage dividing resistor R12 is connected with the third end of the switch unit 130, and the other end of the second voltage dividing resistor R12 is connected with the second end of the switch unit 130; the first direct current power VCC1 is a power source outputting a negative voltage (the voltage of the first end of the first direct current power source is lower than the voltage of the second end), the second end of the switch unit 130 is connected to the second end of the first direct current power source VCC1, the first end of the switch unit 130 is connected to the second light emitting end of the photo switch unit 210 through the third resistor R3, the first light emitting end of the photo switch unit 210 is connected to the first end of the first direct current power source VCC1, the first pole of the voltage stabilizing unit 122 is positive, the second pole of the voltage stabilizing unit 122 is negative, the first signal output end of the photo switch unit 210 is connected to the first end of the second direct current power source VCC2, the first signal output end of the photo switch unit 210 is connected to the second end of the second direct current power source VCC2 through the fourth resistor R4 and the first capacitor C1, the second signal output end of the photo switch unit 210 is connected to the second end of the second direct current power source VCC2 through the fifth resistor R5, and the connection end of the fourth resistor R4 and the first capacitor C1 is a detection output end OUT.

Referring to fig. 6, fig. 6 is a schematic diagram of a power supply circuit applied to the zero-crossing detection circuit of fig. 5 according to an embodiment of the present utility model. The power circuit includes an ac power source 110 to be detected, a first rectifying unit 610, a transforming unit 620, a second rectifying unit 630 and a first rectifying unit 640, where a first input end of the rectifying unit 610 is connected to a first end of the ac power source 110 to be detected, a second input end of the rectifying unit 610 is connected to a second end of the ac power source 110 to be detected, a first output end of the rectifying unit 610 is connected to a first input end of the transforming unit 620, a second output end of the rectifying unit 610 is connected to a second input end of the transforming unit 620, a first output end and a second output end of the transforming unit 620 are respectively connected to two ends of the second rectifying unit 630 to form a first dc power source VCC1, and a third output end and a fourth output end of the transforming unit 620 are connected to two ends of the third rectifying unit 640 to form a second dc power source VCC2, where a voltage of the first end of the first dc power source 1 is lower than a voltage of the second end, and a voltage of the first end of the second dc power source 2 is higher than a voltage of the second end of the second dc power source VCC 1. For example: the voltage of the ac power supply 110 to be detected is 220V, the ac power supply 110 to be detected converts 220V ac power into dc power through the rectifying unit 610, then the dc power is input into the transforming unit 620, 24V ac power and 5V ac power are obtained through the voltage reduction processing of the transforming unit 620, the 24V ac power is processed through the second rectifying unit 630 to obtain-24V first dc power VCC1, and the 5V ac power is processed through the third rectifying unit 640 to obtain +5v second dc power VCC2. Also for example: the voltage of the ac power supply 110 to be detected is 110V, the ac power supply 110 to be detected converts 110V ac power into dc power through the rectifying unit 610, then the dc power is input into the transforming unit 620, the dc power of 12V and the ac power of 5V are obtained through the voltage reduction processing of the transforming unit 620, the dc power of 12V is processed through the second rectifying unit 630 to obtain the first dc power VCC1 of-12V, and the ac power of 5V is processed through the second rectifying unit 630 to obtain the second dc power VCC2 of +5v. In the technical solution of the present embodiment, the voltages of the ac power supply, the first dc power supply VCC1, and the second dc power supply VCC2 are not limited, and may be set according to actual needs. In the technical solution of this embodiment, when the zero crossing detection circuit is applied to an electrical apparatus, the power supply circuit may directly divide the ac power supply 110 to be detected for supplying power to the electrical apparatus, so as to obtain the first dc power supply VCC1 and/or the second dc power supply VCC2 for supplying power to the zero crossing detection circuit, and no separate dc power supply is required to be provided for the zero crossing detection circuit.

Specifically, the X capacitor discharge chip X1 includes an X capacitor discharge chip X1, the X capacitor discharge chip X1 (e.g.power integrations, cap200 series, cap300 series, etc.) can achieve ac input voltage detection with ultra-low input power. When the X capacitor discharge chip X1 is to detect the ac voltage input by the ac power supply 110, the X capacitor discharge chip X1 can achieve a loss of less than 5 mW. When the voltage output from the first end L of the ac power supply 110 to be detected is positive, the zener diode DZ4 is turned on in the forward direction, and the voltage between the zener diode DZ4 and the first voltage dividing resistor R11 is the conduction voltage drop U of the zener diode DZ4 _ZRF Generally, U _ZRF About 1V, the voltage U applied to the third terminal of the switching unit 130 _dirve Is determined by a first voltage dividing resistor R11 and a second voltage dividing resistor R12, U _dirve ＝(Vcc+U _ZRF ) R12/(r11+r12). When the voltage output from the second terminal N of the AC power supply 110 to be detected is positive, the zener diode DZ4 has zener breakdown, i.e. the voltage across the zener diode DZ4 is the breakdown voltage Ub _r At this time, the voltage between the zener diode DZ4 and the first voltage dividing resistor R11 is-Ub _r Then the voltage U applied to the third terminal of the switching unit 130 _dirve Also determined by a first voltage dividing resistor R11 and a second voltage dividing resistor R12, U _dirve ＝(Vcc-U _br ) R12/(r11+r12), where Vcc is the first direct current power Vcc1. For example: vcc=24v, ub _r =25v, r11=r12=10kΩ, when the voltage output from the first terminal L of the ac power supply 110 to be detected is positive, U _dirve ＝(Vcc+U _ZRF ) R12/(r11+r12) =12.5v, the switch unit 130 is turned on, the photosensitive switch unit IC2 is electrically operated, at this time, the phototransistor of the photosensitive switch unit IC2 is turned on, and the zero-crossing detection output terminal OUT outputs a high level signal; when the voltage output by the second terminal N of the AC power source 110 to be detected is positive, U _dirve ＝(Vcc-U _br ) R12/(r11+r12) = -0.5V, when the switch unit 130 is turned off, the photo switch unit IC2 is turned off, that is, the phototransistor in the photo switch unit IC2 is turned off, and the zero crossing detection output terminal OUT outputs a low level signal. It will be appreciated that when the first terminal L of the ac power source 110 to be detected is switched to the second terminal N of the ac power source 110 to be detected, the operating state of the photosensitive switch unit IC2 will change, and the photosensitive switch unit I will beC2 transmits this change to the micro control unit MCU through the zero detection output OUT, the micro control unit MCU will detect the mains switching signal (i.e. zero crossing signal). By means of the zero-crossing detection circuit, the function of detecting a zero-crossing signal can be achieved, the loss of the alternating-current power supply 110 to be detected, which is lower than 5mW and is far lower than the power consumption of 0.22W in the related art, can be achieved through the effect of the X capacitor discharging chip X1, and the function of releasing residual charges on the X capacitor after the alternating-current power supply 110 to be detected is powered off can be achieved.

Referring to fig. 7, fig. 7 is a schematic diagram of a zero-crossing detection circuit according to an embodiment of the present utility model. The zero-crossing detection circuit in this embodiment is configured to detect a zero-crossing condition of the ac power supply 110 to be detected, and includes an acquisition module 120, a voltage division unit, a photosensitive switch unit 210, a third resistor R3, a switch unit 130, a first capacitor C1, a second capacitor C2, a fourth resistor R4, a fifth resistor R5, and a zero-crossing detection output terminal OUT; the to-be-detected alternating current power supply 110 is used for supplying power to the electrical equipment, the to-be-detected alternating current power supply 110 is provided with a first end and a second end, one end of the second capacitor C2 is connected with the first end of the to-be-detected alternating current power supply 110, and the other end of the second capacitor C2 is connected with the second end of the to-be-detected alternating current power supply 110; the acquisition module 120 comprises a constant current unit 121 and a voltage stabilizing diode DZ4 (voltage stabilizing unit 122) connected with the constant current unit 121, and the constant current unit 121 comprises an X capacitor discharge chip X1, a first resistor R1 and a second resistor R2; one end of the first resistor R1 is connected with a first end of the alternating current power supply 110 to be detected, the other end of the first resistor R1 is connected with a first end of the X capacitor discharge chip X1, one end of the second resistor R2 is connected with a second end of the X capacitor discharge chip X1, the other end of the second resistor R2 is connected with a first pole of the voltage stabilizing unit 122, a second pole of the voltage stabilizing unit 122 is connected with a second end of the alternating current power supply 110 to be detected, and the second end is a corresponding end of the first end of the X capacitor discharge chip X1; the voltage dividing unit comprises a first voltage dividing resistor R11 and a second voltage dividing resistor R12, wherein one end of the first voltage dividing resistor R11 is connected with the second end of the X capacitor discharge chip X1, the other end of the first voltage dividing resistor R11 is connected with the third end of the switch unit 130, one end of the second voltage dividing resistor R12 is connected with the third end of the switch unit 130, and the other end of the second voltage dividing resistor R12 is connected with the second end of the switch unit 130; the first direct current power VCC1 is a power source outputting a positive voltage (the voltage of the first end of the first direct current power source is higher than the voltage of the second end), the second end of the switch unit 130 is connected to the second end of the first direct current power source VCC1, the first end of the switch unit 130 is connected to the second light emitting end of the photo switch unit 210 through the third resistor R3, the first light emitting end of the photo switch unit 210 is connected to the first direct current power source VCC1, the first pole of the voltage stabilizing unit 122 is a negative pole, the second pole of the voltage stabilizing unit 122 is a positive pole, the first signal output end of the photo switch unit 210 is connected to the first end of the second direct current power source VCC2, the first signal output end of the photo switch unit 210 is connected to the ground through the fourth resistor R4 and the first capacitor C1, the second signal output end of the photo switch unit 210 is connected to the ground through the fifth resistor R5, and the connection end of the fourth resistor R4 and the first capacitor C1 is the detection output end OUT.

It can be seen that the main difference between the zero detection circuits of fig. 7 and 5 is that the first direct current power VCC1 of fig. 6 is a power source outputting a positive voltage, and the first direct current power VCC1 of fig. 5 is a power source outputting a negative voltage; further, the first pole of the voltage stabilizing unit 122 in fig. 7 is the cathode, the second pole of the voltage stabilizing unit 122 in fig. 5 is the anode, and the first pole of the voltage stabilizing unit 122 in fig. 5 is the cathode.

Referring to fig. 8, fig. 8 is a schematic diagram of a power supply circuit applied to the zero-crossing detection circuit of fig. 7 according to an embodiment of the present utility model. The power circuit includes an ac power source 110 to be detected, a first rectifying unit 610, a transforming unit 620, a second rectifying unit 630 and a first rectifying unit 640, where a first input end of the rectifying unit 610 is connected to a first end of the ac power source 110 to be detected, a second input end of the rectifying unit 610 is connected to a second end of the ac power source 110 to be detected, a first output end of the rectifying unit 610 is connected to a first input end of the transforming unit 620, a second output end of the rectifying unit 610 is connected to a second input end of the transforming unit 620, a first output end and a second output end of the transforming unit 620 are respectively connected to two ends of the second rectifying unit 630 to form a first dc power source VCC1, and a third output end and a fourth output end of the transforming unit 620 are connected to two ends of the third rectifying unit 640 to form a second dc power source VCC2, where a voltage of the first end of the first dc power source 1 is higher than a voltage of the second end, and a voltage of the first end of the second dc power source 2 is higher than a voltage of the second end. For example: the voltage of the ac power supply 110 to be detected is 220V, the ac power supply 110 to be detected converts 220V ac power into dc power through the rectifying unit 610, then the dc power is input into the transforming unit 620, 24V ac power and 5V ac power are obtained through the voltage reduction process of the transforming unit 620, the 24V ac power is processed through the second rectifying unit 630 to obtain +24v first dc power VCC1, and the 5V ac power is processed through the third rectifying unit 640 to obtain +5v second dc power VCC2. Also for example: the voltage of the ac power supply 110 to be detected is 110V, the ac power supply 110 to be detected converts 110V ac power into dc power through the rectifying unit 610, then the dc power is input into the transforming unit 620, the dc power of 12V and the ac power of 5V are obtained through the voltage reduction processing of the transforming unit 620, the dc power of 12V is processed through the second rectifying unit 630 to obtain the first dc power VCC1 of +12v, and the ac power of 5V is processed through the second rectifying unit 630 to obtain the second dc power VCC2 of +5v. In the technical solution of the present embodiment, the voltages of the ac power supply, the first dc power supply VCC1, and the second dc power supply VCC2 are not limited, and may be set according to actual needs. In the technical solution of this embodiment, when the zero crossing detection circuit is applied to an electrical apparatus, the power supply circuit may directly divide the ac power supply 110 to be detected for supplying power to the electrical apparatus, so as to obtain the first dc power supply VCC1 and/or the second dc power supply VCC2 for supplying power to the zero crossing detection circuit, and no separate dc power supply is required to be provided for the zero crossing detection circuit.

Specifically, the X capacitor discharge chip X1 includes an X capacitor discharge chip X1, and this X capacitor discharge chip X1 (for example, cap200 series or Cap300 series of power integrations company) can realize ac input voltage detection with ultra-low input power. When the X capacitor discharge chip X1 is to detect the ac voltage input by the ac power supply 110, the X capacitor discharge chip X1 can achieve a loss of less than 5 mW. When the second end Noutput of the AC power source 110 to be detectedThe voltage between the zener diode DZ4 and the first voltage dividing resistor R11 is the conduction voltage drop U of the zener diode DZ4 when the zener diode DZ4 is positively conducted _ZRF Generally U _ZRF About 1V, the voltage U applied to the third terminal of the switching unit 130 _dirve Is determined by a first voltage dividing resistor R11 and a second voltage dividing resistor R12, U _dirve ＝-U _ZRF * R12/(r11+r12). When the voltage output from the first terminal L of the AC power supply 110 to be detected is positive, the zener diode DZ4 has zener breakdown, i.e. the voltage across the zener diode DZ4 is the breakdown voltage Ub _r At this time, the voltage between the zener diode DZ4 and the first voltage dividing resistor R11 is Ub _r Then the voltage U applied to the third terminal of the switching unit 130 _dirve Also determined by a first voltage dividing resistor R11 and a second voltage dividing resistor R12, U _dirve ＝Ub _r * R12/(r11+r12), where Vcc is the first direct current power supply Vcc1. For example: vcc=24v, ub _r =25v, r11=r12=10kΩ, when the voltage output from the second terminal N of the ac power supply 110 to be detected is positive, U _dirve ＝-U _ZRF * R12/(r11+r12) = -0.5V, the switch unit 130 is turned off, the photo switch unit IC2 is turned off, that is, the phototransistor in the photo switch unit IC2 is turned off, and the zero crossing detection output terminal OUT outputs a low level signal; when the voltage output from the first end L of the AC power source 110 to be detected is positive, U _dirve ＝Ub _r * R12/(r11+r12) = -0.5V, at this time, the switch unit 130 is turned on, and then the photosensitive switch unit IC2 is turned on, that is, the phototransistor in the photosensitive switch unit IC2 is turned on, the photosensitive switch unit IC2 is electrically operated, at this time, the phototransistor of the photosensitive switch unit IC2 is turned on, and the zero crossing detection output terminal OUT outputs a low level signal. It will be appreciated that when the first terminal L of the ac power source 110 to be detected is switched with the second terminal N of the ac power source 110 to be detected, the operating state of the photoswitch unit IC2 will change, and the photoswitch unit IC2 will transmit the change to the micro control unit MCU through the zero detection output terminal OUT, and the micro control unit MCU will detect the mains switching signal (i.e. zero crossing signal). By the zero-crossing detection circuit of the technical scheme of the embodiment, the work of detecting the zero-crossing signal can be realized The function of the X capacitor discharging chip X1 can simultaneously enable the loss of the alternating current power supply 110 to be detected to be lower than 5mW, the power consumption is far lower than 0.22W in the related art, and the function of releasing residual charges on the X capacitor after the alternating current power supply 110 to be detected is powered off can be achieved.

While the preferred embodiment of the present application has been described in detail, the present application is not limited to the above embodiment, and various equivalent modifications and substitutions can be made by those skilled in the art without departing from the spirit of the present application, and these equivalent modifications and substitutions are intended to be included in the scope of the present application as defined in the appended claims.

Claims

1. The zero-crossing detection circuit is characterized by comprising an acquisition module, a switch unit and a zero-crossing detection output unit;

2. The zero-crossing detection circuit of claim 1, wherein the constant current unit comprises an X-capacitor discharge unit.

3. The zero-crossing detection circuit according to claim 2, wherein the constant current unit further comprises a first resistor and a second resistor, one end of the first resistor is connected to a first end of the ac power supply to be detected, the other end of the first resistor is connected to a first end of the X capacitor discharge unit, one end of the second resistor is connected to a second end of the X capacitor discharge unit, the other end of the second resistor is connected to a first pole of the voltage stabilizing unit, the second pole of the voltage stabilizing unit is connected to a second end of the ac power supply to be detected, and the second end is an end corresponding to the first end of the X capacitor discharge unit.

4. The zero-crossing detection circuit according to claim 2, further comprising a voltage dividing unit for dividing a voltage at a junction of the constant current unit and the voltage stabilizing unit to input the divided voltage to a third terminal of the switching unit.

5. The zero crossing detection circuit of claim 4, wherein the voltage dividing unit comprises a first voltage dividing resistor and a second voltage dividing resistor;

6. The zero-crossing detection circuit of claim 1, wherein the zero-crossing detection output unit comprises a photosensitive switching unit and a third resistor, a first light-emitting end of the photosensitive switching unit being a first connection end of the zero-crossing detection output unit;

when the voltage of the first end of the first direct current power supply is lower than that of the second end, the first end of the switch unit is connected with the second light-emitting end of the photosensitive switch unit through the third resistor, the first electrode of the voltage stabilizing unit is positive, and the second electrode of the voltage stabilizing unit is negative;

or alternatively, the process may be performed,

and under the condition that the voltage of the first end of the first direct current power supply is higher than that of the second end, the first end of the switch unit is connected with the second light-emitting end of the photosensitive switch unit through the third resistor, the first electrode of the voltage stabilizing unit is a negative electrode, and the second electrode of the voltage stabilizing unit is a positive electrode.

7. The zero-crossing detection circuit of claim 6, further comprising a second dc power supply, a fourth resistor, a fifth resistor, and a first capacitor, wherein the first signal output of the photosensitive switching unit is connected to the first end of the second dc power supply, the first signal output of the photosensitive switching unit is connected to the second end of the second dc power supply through the fourth resistor, the first capacitor, and the second signal output of the photosensitive switching unit is connected to the second end of the second dc power supply through the fifth resistor, and the connection between the fourth resistor and the first capacitor is the zero-crossing detection output.

8. The zero-crossing detection circuit of claim 1, wherein the zero-crossing detection output unit comprises a sixth resistor, one end of the sixth resistor is a first connection end of the zero-crossing detection output unit, the other end of the sixth resistor is a second connection end of the zero-crossing detection output unit, and the second connection end of the zero-crossing detection output unit is the zero-crossing detection output end.

9. The zero crossing detection circuit of claim 1, further comprising a second capacitor having one end connected to a first end of the ac power source to be detected and another end connected to a second end of the ac power source to be detected.

10. The zero crossing detection circuit of claim 7, further comprising a first rectifying unit, a voltage transforming unit, a second rectifying unit, and a third rectifying unit, wherein a first input terminal of the rectifying unit is connected to a first terminal of the ac power source to be detected, a second input terminal of the rectifying unit is connected to a second terminal of the ac power source to be detected, a first output terminal of the rectifying unit is connected to the first input terminal of the voltage transforming unit, a second output terminal of the rectifying unit is connected to the second input terminal of the voltage transforming unit, a first output terminal and a second output terminal of the voltage transforming unit are respectively connected to two ends of the second rectifying unit to form the first dc power source, and a third output terminal and a fourth output terminal of the voltage transforming unit are respectively connected to two ends of the third rectifying unit to form the second dc power source.

11. An electrical device comprising the zero-crossing detection circuit of any one of claims 1-10.