Low-power-consumption zero-cross detection circuit

Abstract

The utility model, which relates to the technical field of the electronic circuit, provides a low-power-consumption zero-cross detection circuit comprising an X capacitor energy discharge circuit, a step-down circuit, a half-wave detection circuit and an optocoupler drive circuit. The X capacitor energy discharge circuit discharges energy stored on an X capacitor, adjusts discharge time and serves as signal input and a power supply of the half-wave detection circuit, and the step-down circuit converts high-voltage alternating current into low-voltage direct current and provides a power supply for an optocoupler primary stage; the half-wave detection circuit outputs a pulse signal as an input source of an optocoupler driving signal when the alternating-current voltage crosses the zero point; the optocoupler drive circuit converts the detected pulse signal into an isolated zero-crossing signal and transmits the isolated zero-crossing signal to the MCU. According to the utility model, the power consumption of the electronic equipment in a standby state can be reduced, and unnecessary energy consumption is saved; safety is improved, and negative effects of electric shock are avoided; extra cost is reduced, and conventional-grade insulating materials are used; and meanwhile, the service life of elements such as optocouplers is prolonged.

Description

Technical Field

[0001] This utility model relates to the field of electronic circuit technology, specifically to a low-power zero-crossing detection circuit. Background Technology

[0002] Existing zero-crossing detection circuits typically consist of diodes or transistors directly connected to the high-voltage power grid. Some also use optocouplers directly connected to the high-voltage power grid as high-low voltage isolation components. However, existing systems have the following problems:

[0003] 1. High standby power consumption: Current forms loops between circuits, increasing standby power consumption and failing to meet the requirements of green and environmentally friendly concepts.

[0004] 2. Insufficient safety and high additional cost: Using diodes or transistors directly as zero-crossing detection circuits results in non-isolated circuit designs, which can easily lead to electric shock injuries. At the same time, it requires high insulation levels for parts that come into contact with the human body, increasing additional costs.

[0005] 3. Short component lifespan: As a high-low voltage isolation component, the optocoupler is in direct contact with the high-voltage power grid. The changing power grid voltage shortens the lifespan of the optocoupler.

[0006] Therefore, developing a high-efficiency, safe, and low-power standby zero-crossing detection circuit has become an urgent need in the industry. Utility Model Content

[0007] In view of this, in order to solve the problems of high standby power consumption, insufficient safety and short component life of existing zero-crossing detection circuits, the purpose of this utility model is to propose a low-power zero-crossing detection circuit. This circuit can reduce the power consumption of electronic devices in standby mode, save unnecessary energy consumption; improve safety and avoid adverse consequences of electric shock; reduce additional costs by using conventional grade insulation materials; and at the same time improve the service life of components such as optocouplers.

[0008] To achieve the above objectives, this utility model provides the following technical solution:

[0009] To achieve the above objectives, this utility model provides a low-power zero-crossing detection circuit, including an X-capacitor energy discharge circuit, a step-down circuit, a half-wave detection circuit, and an optocoupler drive circuit.

[0010] The X-capacitor energy discharge circuit includes an X-capacitor, a discharge resistor, and a dedicated X-capacitor automatic discharge integrated chip; it is used to discharge the energy stored on the X-capacitor and adjust the discharge time, and serves as the signal input and power supply for the half-wave detection circuit.

[0011] The step-down circuit includes a resistor-capacitor step-down network, a second rectifier circuit, a second filter capacitor, and a second Zener diode; it is used to convert high-voltage AC power into low-voltage DC power to provide power to the primary of the optocoupler.

[0012] The half-wave detection circuit includes an energy storage capacitor, a first rectifier circuit, a first filter capacitor, a first Zener diode, and a directional controller; it is used to output a pulse signal when the AC voltage crosses zero, serving as the input source for the optocoupler drive signal.

[0013] The optocoupler driving circuit includes a MOSFET, a current-limiting resistor, an optocoupler, and a pull-up resistor; it is used to convert the detected pulse signal into an isolated zero-crossing signal and transmit it to the MCU.

[0014] As a further aspect of the present invention, the input terminal of the dedicated X-capacitor automatic discharge integrated chip is connected to the X-capacitor, and the output terminal is grounded through a bleed resistor, which is used to quickly discharge the energy on the X-capacitor; the resistance value of the bleed resistor is configured to adjust the discharge time to ensure that the energy required for the normal operation of the half-wave detection circuit is maintained.

[0015] As a further embodiment of the present invention, the RC step-down network is composed of resistors and capacitors connected in parallel. The input terminal is connected to the AC power grid, and the output terminal is connected in sequence to the second rectifier circuit, the second filter capacitor, and the second Zener diode. The RC step-down network converts the high-voltage AC voltage into a low-voltage AC voltage. The second rectifier circuit converts the low-voltage AC voltage into a pulsating DC voltage. The second filter capacitor filters out the AC component in the pulsating DC voltage, and the second Zener diode is used to protect the subsequent circuit from overvoltage damage.

[0016] As a further embodiment of the present invention, the second rectifier circuit adopts a half-bridge rectifier structure, the second filter capacitor is connected in parallel with the second Zener diode, and outputs a stable low-voltage DC power supply to the optocoupler drive circuit.

[0017] As a further embodiment of the present invention, the input terminal of the energy storage capacitor in the half-wave detection circuit is connected to the output terminal of the X capacitor energy discharge circuit, and the output terminal is sequentially connected to the first rectifier circuit, the first filter capacitor, and the first Zener diode; the first rectifier circuit in the half-wave detection circuit converts the low-voltage AC voltage into a pulsating DC voltage, the first filter capacitor filters out the AC component in the pulsating DC voltage, the first Zener diode is used to protect the subsequent circuit from overvoltage damage, and the directional controller outputs a pulse signal after the zero-point voltage exceeds the threshold.

[0018] As a further embodiment of the present invention, the input terminal of the directional device in the half-wave detection circuit is connected to the output terminal of the first filter capacitor, and a pulse signal is generated when the AC voltage crosses zero, and the optocoupler is driven by the MOS transistor; the MOS transistor in the optocoupler driving circuit serves as the optocoupler driving element, which enhances the driving force of the pulse signal, the current limiting resistor limits the current flowing through the primary of the optocoupler, and the pull-up resistor enhances the driving force of the optocoupler output signal.

[0019] As a further aspect of the present invention, the directional device outputs a pulse signal when it detects the AC voltage crossing zero point, and this pulse signal serves as the optocoupler drive signal.

[0020] As a further embodiment of the present invention, in the optocoupler driving circuit, the gate of the MOS transistor is connected to the output terminal of the directional controller, the source is connected to the primary side of the optocoupler through a current-limiting resistor, and the drain is grounded; the secondary side of the optocoupler is connected to the power supply through a pull-up resistor, and the output terminal generates an isolation pulse signal synchronized with the zero-crossing point of the AC voltage.

[0021] As a further aspect of the present invention, the optocoupler performs opto-isolation, transmitting the input pulse signal to the MCU to achieve safe isolation of the circuit.

[0022] Compared with the prior art, the low-power zero-crossing detection circuit proposed in this utility model has the following beneficial effects:

[0023] The low-power zero-crossing detection circuit of this invention adopts an X-capacitor energy discharge circuit. Through the synergistic effect of a dedicated chip and a discharge resistor, it can quickly discharge energy while avoiding excessive energy loss, thus significantly reducing standby power consumption. The half-wave detection circuit reduces continuous current consumption through energy storage capacitors and intermittent working mode. Combined with the current limiting characteristics of the RC step-down network, it further reduces the overall circuit power consumption and heat generation, achieving low power consumption and heat generation control.

[0024] The low-power zero-crossing detection circuit of this invention also provides isolated DC power to optocoupler U3 through a step-down circuit, avoiding direct contact between the optocoupler and the high-voltage power grid and reducing the risk of electric shock. The design of the bleeder resistor and the automatic discharge chip of X capacitor ensures that the residual charge of X capacitor C1 is quickly discharged after power failure, reducing the dependence on insulation materials and reducing material costs. The conventional RC step-down scheme is used to replace the traditional transformer isolation, which balances low cost and safety.

[0025] This invention's low-power zero-crossing detection circuit adds a MOSFET Q1 and a current-limiting resistor R5 to the optocoupler drive circuit to precisely control the primary conduction current of the optocoupler U3, preventing damage to the optocoupler due to current overload or voltage fluctuations. The cooperation between the Zener diode D2 and the directional controller U2 in the half-wave detection circuit ensures the stability and anti-interference capability of the zero-crossing detection signal, reducing false triggering and component losses. The coordinated design of the bleeder resistor and the X capacitor bleeder chip avoids the long-term impact of high-voltage surges on circuit components, improving the overall system durability.

[0026] In the low-power zero-crossing detection circuit of this invention, the X capacitor energy discharge circuit is reused as the signal input and power supply of the half-wave detection circuit, reducing the number of redundant components and simplifying the circuit structure; the integrated design of the RC step-down network and the half-wave rectifier reduces the circuit complexity while achieving isolated power supply.

[0027] In summary, the low-power zero-crossing detection circuit of this invention solves the problems of high power consumption, poor security, high cost and short component life in the prior art through multi-module collaborative optimization, and has significant technological progress and practical value.

[0028] These or other aspects of this application will become more apparent from the following description of embodiments. It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the application. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this utility model or related technologies, the accompanying drawings used in the description of the exemplary embodiments or related technologies will be briefly introduced below. The drawings are used to provide a further understanding of this utility model and constitute a part of the specification. They are used together with the embodiments of this utility model to explain this utility model and do not constitute a limitation on this utility model. In the drawings:

[0030] Figure 1 This is a circuit diagram of a low-power zero-crossing detection circuit according to an embodiment of the present invention. Detailed Implementation

[0031] The present application will now be further described in conjunction with the accompanying drawings and specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0032] To make the objectives, technical solutions, and advantages of this utility model clearer, the embodiments of this utility model are further described in detail below with reference to specific examples and the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit this application.

[0033] It should be noted that all uses of the terms "first" and "second" in the embodiments of this utility model are for the purpose of distinguishing two different entities or different parameters with the same name. Therefore, "first" and "second" are merely for convenience of expression and should not be construed as limiting the embodiments of this utility model. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, such as other steps or units inherent in a process, method, system, product, or device that includes a series of steps or units.

[0034] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0035] The flowchart shown in the attached diagram is for illustrative purposes only and does not necessarily include all content and operations / steps, nor does it necessarily have to be performed in the order described. For example, some operations / steps can be broken down, combined, or partially merged, so the actual execution order may change depending on the actual situation.

[0036] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0037] To address the problems of high standby power consumption, insufficient safety, and short component lifespan in existing zero-crossing detection circuits, this invention proposes a low-power zero-crossing detection circuit. This circuit can reduce the power consumption of electronic devices in standby mode, saving unnecessary energy; improve safety, avoiding adverse consequences such as electric shock; reduce additional costs by using conventional-grade insulation materials; and simultaneously extend the lifespan of components such as optocouplers.

[0038] See Figure 1 As shown, an embodiment of this utility model provides a low-power zero-crossing detection circuit, including an X-capacitor energy discharge circuit, a step-down circuit, a half-wave detection circuit, and an optocoupler driving circuit. The X-capacitor energy discharge circuit includes an X-capacitor C1, discharge resistors R1, R2, and R3, and a dedicated X-capacitor automatic discharge integrated chip U1; it is used to quickly discharge the energy stored in the X-capacitor while meeting low-power requirements and to adjust the discharge time, and also serves as the signal input and power supply for the half-wave detection circuit.

[0039] In this embodiment, the input terminal of the dedicated X-capacitor automatic discharge integrated chip U1 is connected to the X-capacitor C1, and the output terminal is grounded through the discharge resistors R1, R2, and R3 to quickly discharge the energy on the X-capacitor C1. The resistance values ​​of the discharge resistors R1, R2, and R3 are configured to adjust the discharge time to ensure that the energy required for the normal operation of the half-wave detection circuit is maintained.

[0040] See Figure 1 As shown, the step-down circuit includes a resistor-capacitor step-down network R6 and C4, a second rectifier circuit D3 and D4, a second filter capacitor C5, and a second Zener diode D5; it is used to convert high-voltage AC power into low-voltage DC power to provide power to the primary of the optocoupler and reduce standby power consumption.

[0041] In this embodiment, the RC step-down network consists of a resistor R6 and a capacitor C4 connected in parallel. The input terminal is connected to the AC mains, and the output terminal is sequentially connected to the second rectifier circuits D3 and D4, the second filter capacitor C5, and the second Zener diode D5. The RC step-down network R6 and C4 converts the high-voltage AC voltage into a low-voltage AC voltage. The second rectifier circuits D3 and D4 convert the low-voltage AC voltage into a pulsating DC voltage. The second filter capacitor C5 filters out the AC component in the pulsating DC voltage, and the second Zener diode D5 is used to protect the subsequent circuits from overvoltage damage.

[0042] Among them, the second rectifier circuits D3 and D4 adopt a half-bridge rectifier structure, the second filter capacitor C5 is connected in parallel with the second Zener diode D5, and outputs a stable low-voltage DC power supply to the optocoupler drive circuit.

[0043] See Figure 1 As shown, the half-wave detection circuit includes an energy storage capacitor C2, a first rectifier circuit D1, a first filter capacitor C3, a first Zener diode D2, and a directional controller U2; it is used to output a pulse signal when the AC voltage crosses zero, as the input source of the optocoupler drive signal, thereby reducing circuit power consumption.

[0044] In this embodiment, the input terminal of the energy storage capacitor C2 in the half-wave detection circuit is connected to the output terminal of the X capacitor energy discharge circuit, and the output terminal is sequentially connected to the first rectifier circuit D1, the first filter capacitor C3, and the first Zener diode D2. The first rectifier circuit D1 in the half-wave detection circuit converts the low-voltage AC voltage into a pulsating DC voltage, the first filter capacitor C3 filters out the AC component in the pulsating DC voltage, the first Zener diode D2 is used to protect the subsequent circuit from overvoltage damage, and the directional controller U2 outputs a pulse signal after the zero-point voltage exceeds the threshold.

[0045] In the half-wave detection circuit, the input terminal of the directional controller U2 is connected to the output terminal of the first filter capacitor C3. When the AC voltage crosses zero, a pulse signal is generated and driven by the MOS transistor Q1. In the optocoupler driving circuit, the MOS transistor Q1 serves as the optocoupler driving element, which enhances the driving force of the pulse signal. The current-limiting resistor R5 limits the current flowing through the primary winding of the optocoupler U3, and the pull-up resistor R4 enhances the driving force of the optocoupler output signal.

[0046] In this embodiment, the directional device U2 outputs a pulse signal when it detects the AC voltage crossing zero point, and this pulse signal serves as the optocoupler drive signal.

[0047] The low-power zero-crossing detection circuit of this invention adopts an X-capacitor energy discharge circuit. Through the synergistic effect of a dedicated chip and a discharge resistor, it can quickly discharge energy while avoiding excessive energy loss, thus significantly reducing standby power consumption. The half-wave detection circuit reduces continuous current consumption through the energy storage capacitor C2 and the intermittent working mode. Combined with the current limiting characteristics of the RC step-down network, it further reduces the overall circuit power consumption and heat generation, achieving low power consumption and heat generation control.

[0048] See Figure 1 As shown, the optocoupler driving circuit includes a MOS transistor Q1, a current-limiting resistor R5, an optocoupler U3, and a pull-up resistor R4; it is used to convert the detected pulse signal into an isolated zero-crossing signal and transmit it to the MCU, thereby achieving safe isolation of the circuit and providing a stable zero-crossing signal.

[0049] In this embodiment, in the optocoupler driving circuit, the gate of MOS transistor Q1 is connected to the output terminal of directional controller U2, the source is connected to the primary side of optocoupler U3 through current-limiting resistor R5, and the drain is grounded; the secondary side of optocoupler U3 is connected to the power supply through pull-up resistor R4, and the output terminal generates an isolation pulse signal synchronized with the zero-crossing point of AC voltage. The optocoupler U3 performs opto-isolation, transmitting the input pulse signal to the MCU to achieve safe isolation of the circuit.

[0050] The low-power zero-crossing detection circuit of this invention also provides isolated DC power to optocoupler U3 through a step-down circuit, avoiding direct contact between the optocoupler and the high-voltage power grid and reducing the risk of electric shock. The design of the bleeder resistor and the automatic discharge chip of X capacitor ensures that the residual charge of X capacitor C1 is quickly discharged after power failure, reducing the dependence on insulation materials and reducing material costs. The conventional RC step-down scheme is used to replace the traditional transformer isolation, which balances low cost and safety.

[0051] This invention's low-power zero-crossing detection circuit adds a MOSFET Q1 and a current-limiting resistor R5 to the optocoupler drive circuit to precisely control the primary conduction current of the optocoupler U3, preventing damage to the optocoupler due to current overload or voltage fluctuations. The cooperation between the Zener diode D2 and the directional controller U2 in the half-wave detection circuit ensures the stability and anti-interference capability of the zero-crossing detection signal, reducing false triggering and component losses. The coordinated design of the bleeder resistor and the X capacitor bleeder chip avoids the long-term impact of high-voltage surges on circuit components, improving the overall system durability.

[0052] In the low-power zero-crossing detection circuit of this invention, the X capacitor energy discharge circuit is reused as the signal input and power supply of the half-wave detection circuit, reducing the number of redundant components and simplifying the circuit structure; the integrated design of the RC step-down network and the half-wave rectifier reduces the circuit complexity while achieving isolated power supply.

[0053] In summary, the low-power zero-crossing detection circuit of this invention solves the problems of high power consumption, poor security, high cost and short component life in the prior art through multi-module collaborative optimization, and has significant technological progress and practical value.

[0054] The above are exemplary embodiments disclosed in this utility model. However, it should be noted that various changes and modifications can be made without departing from the scope of the embodiments of this utility model as defined by the claims. The functions, steps, and / or actions of the methods according to the disclosed embodiments described herein do not need to be performed in any particular order. Furthermore, although the elements disclosed in the embodiments of this utility model may be described or claimed individually, they may be understood as multiple unless explicitly limited to a singular number.

[0055] It should be understood that, as used herein, the singular form "a" is intended to include the plural form as well, unless the context clearly supports an exception. It should also be understood that, as used herein, "and / or" refers to any and all possible combinations of one or more of the associatedly listed items. The embodiment numbers disclosed above are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0056] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the present invention (including the claims) is limited to these examples. Within the framework of the present invention, technical features of the above embodiments or different embodiments can also be combined, and many other variations of different aspects of the present invention exist, which are not provided in the details for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A low-power zero-crossing detection circuit, characterized in that, This includes an X-capacitor energy discharge circuit, a step-down circuit, a half-wave detection circuit, and an optocoupler drive circuit; The X-capacitor energy discharge circuit includes an X-capacitor, a discharge resistor, and a dedicated X-capacitor automatic discharge integrated chip; it is used to discharge the energy stored on the X-capacitor and adjust the discharge time, and serves as the signal input and power supply for the half-wave detection circuit. The step-down circuit includes a resistor-capacitor step-down network, a second rectifier circuit, a second filter capacitor, and a second Zener diode; it is used to convert high-voltage AC power into low-voltage DC power to provide power to the primary of the optocoupler. The half-wave detection circuit includes an energy storage capacitor, a first rectifier circuit, a first filter capacitor, a first Zener diode, and a directional controller; it is used to output a pulse signal when the AC voltage crosses zero, serving as the input source for the optocoupler drive signal. The optocoupler driving circuit includes a MOSFET, a current-limiting resistor, an optocoupler, and a pull-up resistor; Used to convert the detected pulse signal into an isolated zero-crossing signal and transmit it to the MCU.

2. The low-power zero-crossing detection circuit as described in claim 1, characterized in that, The input terminal of the dedicated X-capacitor automatic discharge integrated chip is connected to the X-capacitor, and the output terminal is grounded through a discharge resistor; the resistance value of the discharge resistor is configured to adjust the discharge time.

3. The low-power zero-crossing detection circuit as described in claim 2, characterized in that, The RC step-down network consists of resistors and capacitors connected in parallel. The input is connected to the AC power grid, and the output is connected in sequence to the second rectifier circuit, the second filter capacitor, and the second Zener diode.

4. The low-power zero-crossing detection circuit as described in claim 3, characterized in that, The second rectifier circuit adopts a half-bridge rectifier structure, and the second filter capacitor is connected in parallel with the second Zener diode to output a stable low-voltage DC power supply to the optocoupler drive circuit.

5. The low-power zero-crossing detection circuit as described in claim 4, characterized in that, In the half-wave detection circuit, the input terminal of the energy storage capacitor is connected to the output terminal of the X capacitor energy discharge circuit, and the output terminal is sequentially connected to the first rectifier circuit, the first filter capacitor, and the first Zener diode. The first rectifier circuit in the half-wave detection circuit converts the low-voltage AC voltage into a pulsating DC voltage. The first filter capacitor filters out the AC component in the pulsating DC voltage. The first Zener diode is used to protect the subsequent circuit from overvoltage damage. The directional controller outputs a pulse signal after the zero-point voltage exceeds the threshold.

6. The low-power zero-crossing detection circuit as described in claim 5, characterized in that, In the half-wave detection circuit, the input terminal of the directional controller is connected to the output terminal of the first filter capacitor. When the AC voltage crosses zero, a pulse signal is generated and the optocoupler is driven through the MOS transistor.

7. The low-power zero-crossing detection circuit as described in claim 6, characterized in that, The directional device outputs a pulse signal when it detects the AC voltage crossing zero, and this pulse signal serves as the optocoupler drive signal.

8. The low-power zero-crossing detection circuit as described in claim 6, characterized in that, In the optocoupler driving circuit, the gate of the MOS transistor is connected to the output terminal of the directional controller, the source is connected to the primary side of the optocoupler through a current-limiting resistor, and the drain is grounded; the secondary side of the optocoupler is connected to the power supply through a pull-up resistor, and the output terminal generates an isolation pulse signal synchronized with the zero-crossing point of the AC voltage.

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