Zero-crossing detection circuit, chip, smart switch and zero-crossing detection method

Abstract

The application provides a zero-crossing detection circuit, a chip, an intelligent switch and a zero-crossing detection method. The zero-crossing detection circuit is used for detecting the zero-crossing phase of an alternating current signal flowing through an alternating current circuit, and comprises a detection signal generation circuit used for generating detection signals reflecting the alternating current signal at intervals; wherein the detection signals reflect the alternating current signal in a preset zero-crossing phase interval; and a detection circuit connected with the detection signal generation circuit, used for detecting the detection signals based on the zero-crossing phase interval, and outputting a zero-crossing detection signal according to the detection result. The application generates the detection signals corresponding to the alternating current signal at intervals, reduces the working time of sampling electrical devices and detection electrical devices in the zero-crossing detection circuit, and thus reduces the internal loss of the zero-crossing detection circuit.

Description

Technical Field

[0001] This application relates to the field of circuit control technology, and in particular to a zero-crossing detection circuit, chip, smart switch, and zero-crossing detection method. Background Technology

[0002] Smart home appliances are home appliances that incorporate microprocessor, sensor, and network communication technologies. They are characterized by automatically sensing the status of the living space, the appliance's own status, and the appliance's service status. They can automatically control and receive control information from home users, either inside or remotely. Furthermore, as a component of smart homes, smart home appliances can interconnect with other home appliances, furniture, and facilities within the home to form a system and realize smart home functions.

[0003] Currently, common remote control devices for smart home appliances, such as universal remote controls and mobile terminals, all use integrated control information to control the appliances. They do not involve the wiring of the smart appliances, thus allowing them to have a standby mode to process received control information promptly. With the increasing variety of smart home appliances, a panel-type smart switch has emerged that integrates the control and management of both smart and traditional appliances. This overcomes the limitation of remote controls in controlling traditional appliances, but it also creates new problems. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the purpose of this application is to provide a zero-crossing detection circuit, chip, smart switch and zero-crossing detection method to solve the problem of excessive internal loss in the prior art.

[0005] To achieve the above and other related objectives, a first aspect of this application provides a zero-crossing detection circuit for detecting the zero-crossing phase of an AC signal flowing through an AC power line, comprising: a detection signal generation circuit for periodically generating a detection signal reflecting the AC signal; wherein the detection signal reflects at least the AC signal within a preset zero-crossing phase interval; and a detection circuit connected to the detection signal generation circuit for detecting the detection signal based on the zero-crossing phase interval and outputting a zero-crossing detection signal according to the detection result.

[0006] A second aspect of this application provides a chip for detecting the zero-crossing phase of an AC signal flowing through an AC power line, comprising: at least one first pin for acquiring an electrical signal reflecting the AC signal; and at least some of the electrical components in the zero-crossing detection circuit as described in the first aspect.

[0007] A third aspect of this application provides an intelligent switch for connecting to an AC power line containing a load, wherein the intelligent switch comprises: a switching circuit connected to the AC power line and controlled to be turned on or off; a zero-crossing detection circuit as described in the first aspect for outputting a zero-crossing detection signal; and a control circuit connected to the zero-crossing detection circuit for controlling at least the switching circuit to be turned on or off based on the zero-crossing detection signal and received control information.

[0008] A fourth aspect of this application provides a zero-crossing detection method, comprising: intermittently generating a detection signal reflecting an alternating current signal; wherein the detection signal reflects at least an alternating current signal within a preset zero-crossing phase interval; detecting the detection signal based on the zero-crossing phase interval, and outputting a zero-crossing detection signal according to the detection result.

[0009] As described above, the zero-crossing detection circuit, chip, smart switch, and zero-crossing detection method of this application have the following beneficial effects: by using intervals to generate detection signals corresponding to AC signals, the working time of sampling and detection devices in the zero-crossing detection circuit is reduced, thereby reducing the internal consumption of the zero-crossing detection circuit. Attached Figure Description

[0010] Figure 1 The diagram shows a schematic of the frame structure of the zero-crossing detection circuit in one embodiment of this application.

[0011] Figure 2 The diagram shows the waveform correspondence between the detection signal generated by the zero-crossing detection circuit of this application and the AC signal.

[0012] Figure 3 The diagram shown is a schematic diagram of the circuit structure of the first detection signal generation module in one embodiment of this application.

[0013] Figure 4 The diagram shown is a schematic diagram of the circuit structure of the zero-crossing detection circuit in another embodiment of this application.

[0014] Figure 5 The diagram shown is a schematic diagram of the circuit structure of the zero-crossing detection circuit in another embodiment of this application.

[0015] Figure 6 The display shows the waveform of AC power within one power frequency cycle and the waveform of the branch control signal.

[0016] Figure 7 The diagram shown is a schematic diagram of the circuit structure of the zero-crossing detection circuit in another embodiment of this application.

[0017] Figure 8 The diagram shown is a schematic diagram of the circuit structure of the zero-crossing detection circuit in another embodiment of this application.

[0018] Figure 9 The diagram shown is a schematic diagram of the circuit structure of the zero-crossing detection circuit in another embodiment of this application.

[0019] Figure 10 The diagram shows a schematic of the power supply circuit in one embodiment of the zero-crossing detection circuit of this application.

[0020] Figure 11 The diagram shown is a schematic diagram of the power supply circuit in one embodiment of the zero-crossing detection circuit of this application.

[0021] Figure 12 The diagram shown is a schematic diagram of the power supply circuit in another embodiment of the zero-crossing detection circuit of this application.

[0022] Figure 13 The diagram shown is a schematic diagram of the power management circuit in another embodiment of the zero-crossing detection circuit of this application.

[0023] Figure 14 The diagram shown is a schematic diagram of the power management circuit in another embodiment of the zero-crossing detection circuit of this application.

[0024] Figure 15 The diagram shown is a schematic diagram of the circuit structure of the smart switch in one embodiment of this application.

[0025] Figure 16 The flowchart shown is for the zero-crossing detection method of this application.

[0026] Figure 17 The diagram shown is a schematic representation of the circuit structure of the detection circuit in one embodiment of the zero-crossing detection circuit. Detailed Implementation

[0027] The following specific embodiments illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification.

[0028] While the terms first, second, etc., are used in some instances herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, a first preset threshold may be referred to as a second preset threshold, and similarly, a second preset threshold may be referred to as a first preset threshold, without departing from the scope of the various described embodiments. Both the first preset threshold and the preset threshold describe a threshold, but they are not the same preset threshold unless the context explicitly indicates otherwise. A similar situation includes first volume and second volume.

[0029] Furthermore, as used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context indicates otherwise. It should be further understood that the terms “comprising,” “including,” indicate the presence of the stated feature, step, operation, element, component, item, kind, and / or group, but do not preclude the presence, occurrence, or addition of one or more other features, steps, operations, elements, components, items, kinds, and / or groups. The terms “or” and “and / or” as used herein are to be interpreted inclusively, or mean any one or any combination thereof. Thus, “A, B, or C” or “A, B, and / or C” means “any one of: A; B; C; A and B; A and C; B and C; A, B, and C.” Exceptions to this definition occur only when combinations of elements, functions, steps, or operations are inherently mutually exclusive in some way.

[0030] To handle various smart and traditional home appliances, smart switches must be compatible with both the switching control circuits of traditional appliances and the logic control circuits of smart appliances (which may correspond to the control circuits mentioned below). The switching control circuit includes a switching circuit and its control circuit. Examples of switching circuits include relays (or power transistors, etc.) and drivers. Examples of control circuits for the switching circuit include control circuits for adjusting at least one of the following: on-time, off-time, and switching frequency. The logic control circuit refers to controlling the corresponding electronic device through indications in control information, causing the electronic device to switch its operating state according to the indicated content. The control information includes, but is not limited to, at least one of the following: on / off information, temperature information, duration information, timing information, mode information, location information, brightness information, and other indications recognizable by smart home appliances. The logic control circuit includes, but is not limited to, processors, signal transceivers, and external circuits. Examples of processors include CPUs, FPGAs, MCUs, or chips integrating any of these processors. The signal transceiver device includes, but is not limited to: short-range communication modules such as RF communication modules, WiFi communication modules, infrared communication modules, and Bluetooth communication modules; communication modules that can access wide area networks such as fiber optics and broadband; and communication modules that use a SIM card to access mobile networks. The external circuits include, but are not limited to: power supply circuits for providing operating power to the processor, signal transceiver device, etc., and other peripheral circuits. These other peripheral circuits include, but are not limited to, at least one of the following: a first circuit not integrated into the chip that can provide a preset electrical signal to the chip, wherein the electrical signal provided by the first circuit includes, for example, a sampling signal; and a second circuit for processing the electrical signal output by the chip, wherein the second circuit, for example, modulates, divides, amplifies, filters, etc., the electrical signal output by the chip.

[0031] In some intelligent switches that integrate logic control circuits and switching control circuits, the mechanical switching devices (such as relays) in the switching control circuits have a relatively slow response speed. This can easily lead to the load being energized or de-energized during the peak AC voltage range, which is detrimental to the load. Therefore, this response time difference needs to be considered. Currently, some solutions consider adjusting the response time of these switching devices based on the zero-crossing detection signal to compensate for the response time difference. However, current zero-crossing detection circuits have significant internal losses, and these losses make it difficult to maintain the power supply of the device in energy-saving mode.

[0032] Therefore, this application provides a zero-crossing detection circuit. The zero-crossing detection circuit is used to detect the zero-crossing phase of an AC signal flowing through an AC power line to generate a zero-crossing detection signal. Thus, intelligent appliances or intelligent switches can perform switching control, timing, reset, and other operations based on the zero-crossing detection signal.

[0033] The AC power line may include a load, or a load and a switching circuit. The load may be a single load, or connected to the power supply circuit via a series, parallel, or combined series-parallel connection. The switching circuit may be used to individually control the power supply to a load, or configured on an AC power line shared by multiple loads to control the power supply to multiple loads.

[0034] The load is a load circuit that internally includes a voltage (or current) conversion circuit. This conversion circuit converts alternating current into a supply voltage (or supply current). When the supply voltage (or supply current) reaches the operating voltage (or operating current), the load enters the operating state; when the supply voltage (or supply current) does not reach the operating voltage (or operating current), the load exits the operating state. Examples of loads include LED lights, electric curtains, and power adapters. Examples of switching circuits include relays and relay controllers. Taking an LED light as the load, and a relay used to control the conduction or deactivation of the circuit containing the LED light as an example, when the relay is on, the current flowing through the LED light reaches the operating current of the LED (light-emitting diode), and the LED light illuminates; when the relay is off, the current flowing through the LED light does not reach the operating current of the LED, and the LED light turns off.

[0035] The zero-crossing detection circuit can be directly connected to the AC power supply line to the load, or connected to the AC power supply line via a rectifier circuit. The rectifier circuit acquires an AC signal from a current-carrying AC circuit and rectifies the acquired AC signal to output a rectified signal. The rectifier circuit includes, but is not limited to, full-wave rectifier circuits or half-wave rectifier circuits.

[0036] It should be noted that any of the above examples, as well as the AC wires, AC circuits, and AC circuits mentioned below, should be considered to include: wires required for connection to the city power grid, including neutral, live, and ground wires. For example, LED lights and smart switches connected to an AC wire can form a power circuit.

[0037] Please see Figure 1 The diagram shows a frame structure of the zero-crossing detection circuit in one embodiment. The zero-crossing detection circuit includes a detection signal generation circuit 11 and a detection circuit 12.

[0038] The detection signal generation circuit 11 is used to generate detection signals that reflect AC signals at intervals; wherein the detection signals reflect AC signals at least within a preset zero-crossing phase interval.

[0039] The voltage or current of the detection signal reflects the voltage or current of the alternating current signal at the corresponding phase. For example, the voltage or current of the detection signal can be one-Nth of the voltage or current of the alternating current signal at the corresponding phase, or one-Nth of the voltage or current of the rectified alternating current signal at the corresponding phase; where N is greater than 1. Here, the voltage or current of the detection signal generated by the detection signal generation circuit 11 can at least reflect whether the phase of the alternating current signal at the corresponding moment is within or outside the zero-crossing phase interval.

[0040] To reduce the internal losses of the zero-crossing detection circuit, the detection signal generation circuit 11 generates the detection signal intermittently. The intermittent generation of the detection signal means that the detection signal is not synchronized with the AC signal in real time. (See also...) Figure 2 It shows the correspondence between the waveforms of the generated interval detection signal and the AC signal. During the period when the detection signal is generated (or the detection signal is valid) T1, the waveform of the detection signal basically reflects the waveform of the AC signal or the AC signal after rectification. During the period when the detection signal is not generated (or the detection signal is invalid) T2, the waveform of the detection signal is independent of the waveform of the AC signal or the AC signal after rectification.

[0041] In some embodiments, the detection signal generation circuit includes: a first detection signal generation module, which is used to generate a first detection signal reflecting the AC signal through an interval acquisition operation within one power frequency cycle of the AC power, wherein the first detection signal is one of the detection signals.

[0042] Here, the first detection signal generation module reduces the chance of generating a detection signal outside at least the zero-crossing phase interval by periodically sampling the AC signal or the rectified AC signal. The power frequency period is the inherent period of the AC power. Periodically sampling the AC signal or the rectified AC signal within one power frequency period yields sampled signals reflecting the AC signal in different phase intervals within that period. The first detection signal generation module outputs a first detection signal based on the obtained sampled signals.

[0043] In some examples, the first detection signal generation module can be connected to the detected AC line via a rectifier circuit. The first detection signal generation module acquires the rectified signal at time intervals less than one power frequency cycle of the AC line and outputs the acquired rectified signal as the first detection signal. The rectifier circuit includes a full-wave rectifier circuit or a half-wave rectifier circuit.

[0044] In some other examples, the first detection signal generation module can be directly connected to the AC line being detected. The first detection signal generation module collects AC signals at time intervals less than one power frequency cycle of the AC line, and rectifies the collected AC signals to output them as the first detection signal.

[0045] In some specific examples, the first detection signal generation module includes a sampling submodule and a control submodule.

[0046] The sampling submodule includes at least one switch M2, which is located on the line where the data acquisition operation is performed. For example, switch M2 is located on a sampling line connected to an AC power line. Alternatively, switch M2 is located on a sampling line connected to a rectifier circuit. When switch M2 is on, the sampling submodule performs the data acquisition operation; conversely, when switch M2 is off, the sampling submodule stops performing the data acquisition operation. Therefore, performing the data acquisition operation can be considered as the process by which the sampling submodule generates a first detection signal from the acquired sampling signal; stopping the data acquisition operation can be considered as the process by which the sampling submodule cannot obtain a sampling signal. The process by which the sampling submodule performs interval data acquisition within one power frequency cycle of the AC power supply refers to the process by which switch M2 performs at least one set of on / off operations within one power frequency cycle. The set of on / off operations may occur only when the phase of the AC signal is within the zero-crossing phase interval, or only when the phase of the AC signal is outside the zero-crossing phase interval, or during the period when the phase of the AC signal moves from outside the zero-crossing phase interval into the zero-crossing phase interval, or during the period when the phase of the AC signal moves from inside the zero-crossing phase interval into outside the zero-crossing phase interval.

[0047] Please see Figure 3The diagram shows a circuit structure of the first detection signal generation module in one embodiment, wherein the switch M2 in the sampling submodule 411 is turned on or off under the control of the control submodule 412.

[0048] The sampling submodule 411 includes a rectifier bridge RB3, a switch M2, and a sampling resistor HV_Resistor. The rectifier bridge is connected to the AC power line and to the switch M2 and the sampling resistor HV_Resistor. When the switch M2 is on, the sampling resistor HV_Resistor collects the rectified signal output by the rectifier bridge RB3 and outputs a first detection signal. When the switch M2 is off, the sampling resistor HV_Resistor cannot collect the rectified signal and cannot output the first detection signal, thus achieving the purpose of intermittently outputting the first detection signal. The switch M2 can be an N-type power transistor. In fact, those skilled in the art should readily understand that the switch M2 can be replaced by a P-type power transistor, a bipolar transistor, etc., depending on the actual circuit design requirements.

[0049] Taking a sampling submodule including a rectifier bridge RB3, a switch M2, and a sampling resistor HV_Resistor as an example, the control submodule 412 controls the switch M2 to be turned on or off. To this end, the control submodule 412 is connected to the control terminal of the switch M2 and outputs a sampling control signal by detecting the first detection signal or a zero-crossing detection signal to control the switch M2 to be turned on or off. Here, to ensure that the sampling submodule 411 can acquire sampling signals falling within the zero-crossing phase interval, the control submodule 412 controls the duration of the switch M2 being turned on or off by detecting the voltage of the first detection signal. The control submodule 412 outputs a sampling control signal representing the duration of the switch M2 being turned on or off through its electrical connection to the control terminal of the switch M2. For example, the control submodule 412 presets a reference voltage interval that covers the zero-crossing voltage interval corresponding to the zero-crossing phase interval. For example, the upper voltage limit V1 of the reference voltage range is greater than or equal to the upper voltage limit V2 of the zero-crossing voltage range, and the lower voltage limit V1' of the reference voltage range is less than or equal to the lower voltage limit V2' of the zero-crossing voltage range. Another example is that the upper voltage limit V1 of the reference voltage range is greater than or equal to the upper voltage limit V2 of the zero-crossing voltage range, and the lower voltage limit V1' of the reference voltage range falls within the zero-crossing voltage range. Yet another example is that the reference voltage range is equal to the zero-crossing voltage range.

[0050] In some specific examples, the control submodule 412 first controls the switch M2 to conduct intermittently according to a preset time interval, and detects the voltage of the first detection signal during the conduction of switch M2. When the voltage of the first detection signal falls within the reference voltage range, the control submodule 412 continuously outputs a sampling control signal to keep the switch M2 in the sampling submodule 411 always conducting until zero is detected and the voltage of the first detection signal exceeds the reference voltage range. At this point, the control submodule 412 controls the switch M2 to open and controls the switch M2 to conduct intermittently according to the preset time interval. The preset time interval can be a fixed value set according to actual application requirements, or it can be set based on the time interval of detecting the zero-crossing detection signal.

[0051] For example, the control submodule 412 includes a signal generator, a comparator, and a selector. The comparator compares the voltage v of the first detection signal with the upper voltage limit V1 of the reference voltage range. When the voltage v of the first detection signal is greater than or equal to the upper voltage limit V1, the selector, based on the comparison result output by the comparator, connects the control terminals of the signal generator and the switch M2, so that the switch M2 is controlled by the sampling control signal (such as a square wave signal) output by the signal generator and is turned on and off according to a preset on / off cycle. When the voltage v of the first detection signal is less than the upper voltage limit V1, the selector, based on the comparison result output by the comparator, connects the control terminal of the switch to a constant voltage terminal, so that the control terminal of the switch is always on due to the constant voltage signal provided by the constant voltage terminal. In other words, the control submodule outputs a sampling control signal that is always valid within the reference voltage range. Depending on the type of switch in the actual circuit design, the constant voltage terminal can be a voltage ground terminal or the output terminal of a reference voltage source.

[0052] In some specific examples, the control submodule 412 first controls the switch M2 to be turned on intermittently according to a preset time interval, and detects the voltage of the first detection signal during the period when the switch M2 is turned on. When the voltage of the first detection signal falls into the reference voltage range, at least one of the duty cycle and frequency of the sampling control signal is adjusted to ensure that the voltage of the first detection signal output by the sampling submodule 411 at intervals falls into the zero-crossing voltage range. For example, the control submodule 412 includes an adjustable signal generator and a comparator, wherein the comparator compares the voltage v of the first detection signal with the upper voltage limit V1. When the voltage v of the first detection signal is less than or equal to the upper voltage limit V1, based on the comparison result output by the comparator, the adjustable signal generator outputs a sampling control signal with a first duty cycle to the control terminal of the switch, so that the switch M2 is controlled by the square wave control signal output by the signal generator and is turned on and off according to the period of the square wave control signal. When the voltage v of the first detection signal is greater than the upper voltage limit V1, based on the comparison result output by the comparator, the adjustable signal generator adjusts the duty cycle of the sampling control signal to a second duty cycle and outputs it to the control terminal of the switch; wherein the second duty cycle is less than the first duty cycle.

[0053] In some specific examples, the control submodule outputs the sampling control signal by detecting a zero-crossing detection signal. Here, when the control submodule detects that the zero-crossing detection signal is valid, it outputs a sampling control signal to control the switch to turn off and starts a sampling interval timer; when the sampling interval timer reaches a sampling interval threshold, the control submodule adjusts the sampling control signal to control the switch to turn on.

[0054] The sampling interval threshold can be a fixed value less than half a power frequency cycle, or it can be set based on the time interval between multiple zero-crossing detection signals. For example, the control submodule includes a storage medium, a timer, an adder, a subtractor, an MCU, etc., where the storage medium includes a latch or flash memory. The control submodule times the time interval between the zero-crossing detection signals and stores it in the storage medium. By calculating the average of multiple time intervals, the maximum value of the sampling interval threshold is determined. Therefore, the control submodule can choose this average value as the sampling interval threshold, or reduce this average value to obtain the sampling interval threshold, etc.

[0055] Based on the sampling interval threshold determined in any of the above examples, the control submodule adjusts the branch control signal to control the switch M2 to turn on and off. During the period when the control switch M2 is on, the sampling submodule generates a first detection signal and outputs it to the detection circuit.

[0056] The aforementioned first detection signal generation module can be used for AC power lines equipped with a switching circuit and a load. As mentioned earlier, the switching circuit and load supply AC power to the load when the switching circuit is on, enabling the load to operate. When the switching circuit is off, the AC power cannot provide the energy required for the load to operate, and the load does not operate. During the period when the switching circuit is off, the zero-crossing detection circuit provides a energizing loop to provide a small current AC power supply while maintaining the load's inactivity. Using this energizing loop, the first detection signal generation module intermittently acquires AC power signals or rectified AC power signals to generate the first detection signal. This energizing loop can be constructed using a high-resistance resistive device connected to the AC power line and a voltage ground, or it can be constructed using a power supply circuit connected to the AC power line. The power supply circuit will be described in detail later.

[0057] In other embodiments, the detection signal generation circuit acquires an AC signal or a rectified AC signal via a selection circuit disposed on the AC power line. For this purpose, please refer to [link to relevant documentation]. Figure 4 The diagram shows a schematic of the zero-crossing detection circuit in another embodiment. The zero-crossing detection circuit further includes the selection circuit 21, which is used to select whether the AC line is connected to the first line or the second line to form a corresponding energized circuit. The detection signal generation circuit includes a second detection signal generation module 421, which generates a second detection signal reflecting the AC signal flowing through the second line when the selection circuit 21 selects the second line, and outputs this second detection signal as the detection signal.

[0058] The selection circuit 21 connects the AC power line to the second line within a preset reference phase interval of the AC power supply, and connects the load to the first line outside the reference phase interval. The reference phase interval can be determined according to the actual circuit design. For example, to ensure the normal operation of the load on the AC power line, the reference phase interval is selected as the phase interval corresponding to the voltage range outside the load's operating voltage range; it can coincide with or cover the zero-crossing phase interval. Taking an LED light as an example, the reference phase interval is selected as a phase interval that covers the zero-crossing phase interval.

[0059] In some examples, the selection circuit 21 includes a switching unit M1 disposed on the AC power line. A load is also disposed on the AC power line.

[0060] The switching unit M1 is configured to be controlled to turn on or off based on a received shunt control signal, in order to respond at least immediately to a switching operation that switches the load from access to the second line to access to the first line. Specifically, the switching unit M1 is controlled to turn off based on the received shunt control signal to allow the load to access the second line immediately or with a delay, and is controlled to turn on based on the shunt control signal to allow the load to access the first line immediately. In some examples, the selection circuit further includes an on / off control device that generates a shunt control signal by detecting the phase of the alternating current and outputs it to the switching unit M1. In other examples, the shunt control signal is output to the switching unit by a detection signal generation circuit. The switching unit M1 includes a power transistor, wherein the control terminal of the power transistor is used to receive a branch control signal, which is a voltage signal. When the branch control signal indicates that the switching unit M1 is turned on, the power transistor is turned on, so that the load and the AC line thereon are connected to the neutral wire via the first line, and the load and the AC line thereon are connected between the live wire and the neutral wire of the AC power supply. When the branch control signal indicates that the switching unit M1 is turned off, the power transistor is turned off, so that the load and the AC line thereon are connected to the voltage ground in the zero-crossing detection circuit via the second line, and the load and the AC line thereon are connected between the live wire and the voltage ground.

[0061] To maximize the efficiency of active power utilization of AC power, the structure of the selection circuit is related to the zero-crossing detection circuit and its peripheral circuits and loads mentioned in this application. The peripheral circuits include, but are not limited to, rectifier circuits. The second detection signal generation module is connected to the AC power line through the rectifier circuit. Taking a full-wave rectifier circuit as an example, when the phase of the AC power falls within the reference phase interval, the selection circuit immediately selects the second line based on a time-division control signal; and when the phase of the AC power exceeds the reference phase interval, the selection circuit immediately selects the first line based on the time-division control signal.

[0062] Please refer to the actual circuit structure of the rectifier circuit and zero-crossing detection circuit. Figure 5 The diagram shows a circuit structure schematic of the zero-crossing detection circuit in another embodiment. The selection circuit 21 further includes a phase limiting unit. For example, the rectifier circuit is a half-wave rectifier circuit, and the phase limiting unit forces the AC signal to flow through the first line during the negative half-cycle of the power frequency cycle.

[0063] Here, the phase limiting unit may be a separate electrical device or provided by a parasitic diode in the semiconductor device of the switching unit M1. In some examples, the phase limiting unit is a separate electrical device connected in parallel with the switching unit, used to delay or immediately perform a switching operation to switch the load from access to the first line to access to the second line, depending on the phase of the current alternating current when the switching unit is open. The phase limiting unit includes a diode D1 connected in parallel with the switching unit M1, with its cathode connected to the live wire and its anode connected to the neutral wire.

[0064] Taking the switching operation of the selection circuit within one AC power frequency cycle as an example, when the switching unit M1 is turned on, the load is connected between the live wire and the neutral wire of the AC power through the conducting connection of the switching unit M1, and the diode D1 is short-circuited. In other words, the selection circuit 21 is connected to the first line. When the switching unit M1 is turned off and the diode D1 is turned on, the load is still connected between the live wire and the neutral wire of the AC power. In other words, the selection circuit 21 remains on the first line. When the switching unit M1 is turned on and the diode D1 is turned off, with the change of AC power phase, the voltage difference across the rectifier circuit in the second line is greater than its conduction voltage, and the selection circuit switches from the first line to the second line.

[0065] As shown in the above example, if the phase of the AC current falls within the negative half-cycle (-180-0 degrees) of the power frequency cycle when the switching unit is turned off, the selection circuit delays switching to the second line until the AC current phase enters the positive half-cycle (0-180 degrees) of the power frequency cycle. Furthermore, the second line conducts when the AC current voltage reaches the turn-on voltage of the rectifier bridge in the rectifier circuit. Conversely, if the phase of the AC current falls within the positive half-cycle (0-180 degrees) of the power frequency cycle when the switching unit is turned off, the selection circuit immediately switches to the second line. And the second line conducts when the AC current voltage reaches the turn-on voltage of the rectifier bridge in the rectifier circuit.

[0066] It should be noted that, depending on the selection of electrical components such as the rectifier circuit and the selection circuit, and the selection of the operating voltage of semiconductor devices such as diodes and power transistors, when the selection circuit switches between the first and second lines, it may be limited by the operating voltage of the corresponding semiconductor device, which may result in the corresponding line being momentarily unconducted. For example, the voltage of AC signals corresponding to phases of 0, -180, and 180 degrees, and those near these phases, may not reach the operating voltage of the diode. In such cases, the selection circuit should be considered to have selected either the first or second line, and is only in a temporary unconducted state of the corresponding line at the corresponding instant. However, this does not affect the technical concept mentioned in this application of using time-sharing AC power to enable the zero-crossing detection circuit to output a zero-crossing detection signal through interval detection. Similarly, when the selection circuit switches between the first and second lines, the switching operation of the first and second lines in the actual circuit may not be completely consistent with the instantaneous situation in the example above due to the limitations of the operating voltage of the corresponding semiconductor devices and the charging and discharging of parasitic capacitances. For example, there may be transient situations such as both the first and second lines being on or off. This should not affect the technical idea mentioned in this application of using time-sharing AC power to enable the zero-crossing detection circuit to output a zero-crossing detection signal through interval detection. This will not be repeated hereafter.

[0067] Based on the switching operation of the selection circuit described above, the detection signal generation circuit controls the selection circuit to switch between the first and second lines within one power frequency cycle. Thus, the detection signal generation circuit can acquire an electrical signal reflecting the AC signal on the second line. This electrical signal can be an AC signal or a rectified AC signal. Therefore, the detection signal generation circuit includes a second detection signal generation module, which generates a second detection signal reflecting the AC signal flowing through the second line when the selection circuit selects the second line, and outputs this second detection signal as the detection signal.

[0068] In some examples, the second detection signal generation module directly samples the AC signal on the second line to obtain the second sampling signal. In other examples, the second detection signal generation module samples the rectified AC signal output by the rectifier circuit on the second line. Specifically, the second detection signal generation module includes first voltage divider resistors R21 and R22 connected between the output terminal of the rectifier circuit and ground; wherein R22 is grounded. The rectified signal output by the rectifier circuit on the second line is called the second rectified signal. The second detection signal generation module may also include second voltage divider resistors R23 and R24 connected in parallel with the voltage divider resistor R22. The second detection signal output by the second detection signal generation module is directly output to the detection circuit on one hand, and directly, or after amplification or further voltage division, output to the shunt control module in the detection signal generation circuit on the other hand. The electrical signal output by the second detection generation module to the shunt control module can be called the second sampling signal. The electrical components (groups) used to provide the second sampling signal to the shunt control module can also be called the second sampling circuit. The second sampling circuit can be located on the second line, such as in a position where it is connected to an AC power line; or, for example, at the output terminal of a rectifier circuit on the second line. Depending on the actual circuit design requirements, the second sampling circuit and the second detection signal generation module can share common electrical components, such as common voltage divider resistors.

[0069] In some specific examples, the time-division control signal received by the selection circuit is provided by the zero-crossing detection circuit. Still as Figure 5 As shown, the zero-crossing detection circuit further includes a second sampling circuit 25, and the detection signal generation circuit further includes a branch control module 233.

[0070] The second sampling circuit 25 is used to sample the AC signal flowing through the second line to generate a second sampling signal. In some examples, the second sampling circuit directly samples the AC signal on the second line to obtain the second sampling signal. In other examples, the second sampling circuit samples the rectified AC signal output by the rectifier circuit located on the second line. Specifically, the second sampling circuit includes first voltage divider resistors R21 and R22 connected between the output terminal of the rectifier circuit and ground; wherein R22 is grounded. The rectified signal output by the rectifier circuit located on the second line is called the second rectified signal. The second sampling circuit may also include second voltage divider resistors R23 and R24 connected in parallel with the voltage divider resistor R22. The second sampling circuit may be fully or partially integrated into the chip containing the power management circuit. For example, the first voltage divider resistors R21 and R22 in the second sampling circuit are externally connected between the rectifier circuit and the chip through the chip pin FB2, and provide the first voltage divider signal of the second rectified electrical signal to the chip pin FB2. The second voltage divider resistors R23 and R24 in the second sampling circuit are integrated in the chip, and the first voltage divider signal is further divided through the pin FB2 to obtain the second sampling signal and provide it to the internal branch control module of the chip.

[0071] The branch control module detects the second sampling signal and outputs a branch control signal to the selection circuit to control the selection circuit to switch between the first line and the second line.

[0072] For example, such as Figure 5 As shown, the selection circuit 21 is connected to the second line by default, and the rectifier circuit outputs a full-wave rectified electrical signal. When the shunt control module 233 detects that the voltage of the second sampled signal exceeds a preset voltage range, it outputs a shunt control signal to control the selection circuit to switch from the second line to the first line and starts a timer. When the timer reaches a timer threshold, the shunt control module 233 adjusts the shunt control signal to control the selection circuit 21 to switch from the first line to the second line. The timer threshold is related to the power frequency cycle. For example, the timer threshold t is a fixed value less than one power frequency cycle, or it is set according to the duration for which the selection circuit selects the first line within at least one switching cycle; wherein the switching cycle is less than the power frequency cycle of the AC power. In some examples, the switching cycle is less than half the power frequency cycle of the AC power to ensure that each zero-crossing phase of the AC signal is detected within one power frequency cycle. For example, please refer to... Figure 6 It displays the waveform of the alternating current within one power frequency cycle and the waveform of the shunt control signal. When the shunt control module 233 detects that the voltage of the second sampled signal exceeds a preset voltage range, that is, in... Figure 6At time TT1, the output shunt control signal controls the selection circuit to switch from the second line to the first line and starts a timer. After the timer reaches the timer threshold t, i.e., at time TT2, the shunt control module 233 adjusts the shunt control signal to control the selection circuit 21 to switch from the first line to the second line. Starting from time TT2, the shunt control module 233 detects the voltage of the second sampled signal, and at the same time, the second detection signal generation module generates a second detection signal. Until time TT3, the shunt control module 233 detects again that the voltage of the second sampled signal exceeds the preset voltage range and adjusts the shunt control signal to control the selection circuit to switch from the second line to the first line. This process is repeated so that the zero-crossing detection circuit can output a zero-crossing detection signal for each zero-crossing phase of the corresponding AC signal.

[0073] Combination Figure 5 The selection circuit shown is illustrated, and the control process of the shunt control module 233 on the selection circuit is described using the example of the selection circuit performing one switching cycle within one AC power frequency cycle. The selection circuit 21 is connected to the second line by default, and the rectifier circuit outputs a half-wave rectified signal. When the shunt control module 233 detects that the voltage of the second sampled signal does not fall into the reference voltage range, it outputs a shunt control signal to control the switching unit M1 to conduct, that is, the selection circuit 21 switches from the second line to the first line; and after a delay, the shunt control module 233 adjusts the shunt control signal to make the switching unit M1 disconnect. At the moment when the switching unit M1 is disconnected, the shunt control module 233 detects that the voltage of the second sampled signal falls into the reference voltage range, and then maintains the current shunt control signal; at the same time, the second detection signal generation module generates a second detection signal; until the shunt control module 233 detects that the voltage of the second sampled signal exceeds the reference voltage range again, it adjusts the shunt control signal to control the switching unit M1 to conduct again, that is, the selection circuit 21 switches from the second line to the first line again.

[0074] Please see Figure 7The diagram shows a circuit diagram of a zero-crossing detection circuit in another embodiment. The branch control module includes a comparison sub-circuit and a control sub-circuit. The comparison sub-circuit compares the voltage of the second sampled signal with the reference voltage range and generates a corresponding comparison result. The voltage range may include upper and lower voltage thresholds, or only the upper voltage threshold (or lower voltage threshold). The lower voltage threshold of the reference voltage range is a voltage value of zero or close to zero, and the upper voltage threshold is a reference voltage Vref3. When the comparison sub-circuit detects that the voltage of the second sampled signal is higher than Vref3, the output detection signal (e.g., a high level) indicates that the voltage of the rectified signal exceeds the zero-crossing voltage range; when the comparison sub-circuit detects that the voltage of the second sampled signal is lower than or equal to Vref3, the output detection signal (e.g., a low level) indicates that the voltage of the second sampled signal is within the zero-crossing voltage range.

[0075] The control subcircuit is connected to the comparison subcircuit and is used to output the shunt control signal based on the comparison result to control the selection circuit to switch from the second line to the first line, i.e., the switching circuit is connected to the first line or the second line. The control subcircuit includes logic devices (groups) that output the shunt control signal based on control logic set according to the received detection signal. The logic devices (groups) include, but are not limited to, logic gates and flip-flops. For example, when the control subcircuit receives a high-level signal, it outputs a shunt control signal to switch the selection circuit from the second line to the first line according to preset control logic. Taking a switching unit M1 in the selection circuit containing an N-type power transistor as an example, when the shunt control signal output by the control subcircuit through the GATE pin is a high-level signal, it indicates that the N-type power transistor is turned off, and the selection circuit switches from the second line to the first line.

[0076] The control subcircuit also includes a timer, which is controlled by a second detection signal output by the comparator subcircuit. When the voltage of the second detection signal exceeds the voltage range corresponding to the reference phase range, the timer is started, and when the elapsed duration reaches a timing threshold, a timeout detection signal is output. The logic devices (groups) in the control subcircuit, based on the control logic of the second detection signal and the timeout detection signal output by the comparator subcircuit, adjust the branch control signal to switch the selection circuit from the first line to the second line. Combined with... Figure 7The example shown, along with the switching unit M1, includes an N-type power transistor. When the shunt control signal transitions from high to low, the N-type power transistor turns on, and the selection circuit switches from the first line to the second line during the positive half-cycle of the AC power. The timing threshold is a fixed time threshold or is set based on the duration for which the selection circuit selects the first line within at least one switching cycle; wherein the switching cycle is less than the AC power frequency cycle. Here, the switching cycle refers to the duration for the selection circuit to experience one switch from the first line to the second line and then back to the first line. The switching cycle is less than the AC power frequency cycle; in some examples, the switching cycle is less than half the AC power frequency cycle to ensure that two zero-crossing phases experienced within one power frequency cycle can be detected.

[0077] In another example, to improve the accuracy of the timer, the control subcircuit further includes a timer controller for monitoring and storing the time t' required from the turn-on of switch unit M1 until the selection circuit switches to the second line, and adjusting the timing threshold based on at least one monitored time t'. The timer controller includes at least a latch and logic devices (groups), a timer resetter, etc. The logic devices (groups) include, but are not limited to, at least one or a combination of the following: comparators, gate devices, amplifiers, adders, subtractors, etc. For example, the branch control signal that turns on switch unit M1 is used as a trigger signal, the timer starts timing, and ends timing when the rectifier circuit is detected to be on, storing the current time t' in the latch as the timing reference threshold for the next cycle. Another example is detecting the timing duration of the timer (i.e., the time interval between the turn-on time of switch unit M1 and the turn-on time of the rectifier circuit) over multiple switching cycles, and using the multiple detected timing durations as the timing reference threshold for the current switching cycle.

[0078] In other examples, to prevent the voltage of the rectified electrical signal received by the zero-crossing detection circuit from being too high when the selection circuit switches to the second line, which could easily damage the components within the zero-crossing detection circuit, the zero-crossing detection circuit further includes a first protection module. This module detects the voltage of the electrical signal reflecting the AC signal flowing through the second line, and when the detected voltage exceeds a preset protection voltage threshold, controls the selection circuit to switch from the second line to the first line. The electrical signal reflecting the AC signal flowing through the second line can be either a second sampling signal or a second detection signal.

[0079] Please see Figure 8The diagram shows a schematic of a zero-crossing detection circuit in another embodiment. The first protection module 234 is connected in parallel with the branch control module 233 and detects the voltage of the second sampled signal. Here, the first protection module 234 can directly compare the voltage of the second sampled signal with a preset protection voltage threshold, or it can perform voltage division or amplification of the second sampled signal before comparing it with the protection voltage threshold. When the voltage of the second sampled signal is higher than the preset protection voltage threshold, the selection circuit is controlled to switch from the second line to the first line. The protection voltage threshold is higher than or equal to the upper voltage limit of the voltage range corresponding to the aforementioned reference phase interval.

[0080] For example, the first protection module includes a comparator A5 and a controlled switch M5. The controlled switch M5 is connected between the control terminal of the selection circuit and a preset voltage. One input of the comparator A5 receives a second sampling signal, and the other input receives a protection voltage threshold. The output of the comparator A5 is connected to the control terminal of the controlled switch M5. When the comparator A5 detects that the voltage of the second sampling signal is higher than the protection voltage threshold, it controls the controlled switch M5 to conduct. The voltage at the control terminal of the selection circuit is forced to be set to the preset voltage. Thus, the selection circuit is forced to switch to the first line, i.e., the energized circuit consisting of at least an AC line, a load, and the urban power grid. Simultaneously, or with a slight delay, the shunt control module also outputs a shunt control signal to switch the selection circuit to the first line and maintains the shunt control signal for the delay period. When the comparator A5 detects that the voltage of the second sampling signal is not higher than the protection voltage threshold, it controls the controlled switch M5 to deactivate. The voltage at the control terminal of the selection circuit is determined by the shunt control signal output by the shunt control module. Thus, the selection circuit switches between the first line and the second line according to the control of the shunt control module.

[0081] The aforementioned second detection signal generation module can be used for AC power lines equipped with a switching circuit and a load. The switching circuit and load have been mentioned above. When the switching circuit is on, AC power supplies the load to enable it to operate; when the switching circuit is off, the AC power cannot provide the energy required for the load to operate, and the load does not operate. Here, the second detection signal generation module is used to acquire a phase-cut AC power signal through the selection operation of the selection circuit during the on-state of the switching circuit, thereby generating a second detection signal. That is, the second detection signal generation module generates the second detection signal by directly acquiring the phase-cut AC power signal or by acquiring the phase-cut and rectified AC power signal.

[0082] The zero-crossing detection circuit further includes a detection circuit connected to the detection signal generation circuit, used to detect the detection signal based on the zero-crossing phase interval, and output a zero-crossing detection signal according to the detection result.

[0083] Here, the detection circuit presets a zero-crossing voltage range or a zero-crossing current range corresponding to the zero-crossing phase range based on the voltage or current of the detection signal output by the detection signal generation circuit, and uses detection logic composed of logic devices (groups) to detect the detection signal, and outputs a zero-crossing detection signal representing the current AC zero-crossing phase based on the detection result.

[0084] In some examples, the detection circuit includes a zero-crossing detection module for detecting the voltage of the received detection signal based on the zero-crossing voltage interval corresponding to the zero-crossing phase interval, and outputting the zero-crossing detection signal based on the detection result. For example, the zero-crossing detection module includes a comparator that compares the voltage v of the detection signal with the upper voltage limit V2 of the zero-crossing voltage interval. When the voltage v of the detection signal is less than or equal to the upper voltage limit V2, the output zero-crossing detection signal indicates that the phase of the current AC power is within the zero-crossing phase interval; otherwise, the output zero-crossing detection signal indicates that the phase of the current AC power is not within the zero-crossing phase interval. Here, the zero-crossing detection signal level signal, according to the actual circuit design of the zero-crossing detection module, uses a pulse width signal composed of high and low levels to describe the zero-crossing detection signal, and the duration of the effective pulse width used to represent the zero-crossing phase interval can be very small. In some examples, the duration of the effective pulse width of the zero-crossing detection signal is determined based on the duration for which the detection signal falls within the zero-crossing voltage interval. For example, if the first detection signal is continuously output within the reference voltage range, the zero-crossing detection module obtains a zero-crossing detection signal based on the detection of the first detection signal within the zero-crossing voltage range; wherein the effective pulse width of the zero-crossing detection signal is less than or equal to the duration during which the detection signal falls within the zero-crossing voltage range. In some other examples, the effective pulse width of the zero-crossing detection signal is determined based on the operation duration of the control submodule in the branch control module or the first detection signal generation module. For example, when the branch control module receives a valid zero-crossing detection signal, it controls the switching unit in the selection circuit to turn on. When the switching unit is on, the selection circuit selects and switches to the first line. Thus, since no AC signal flows into the second line, the zero-crossing detection signal changes from valid to invalid. Therefore, the effective pulse width of the zero-crossing detection signal is related to the response duration of the branch control module and the switching unit. According to the descriptions of the above examples, the zero-crossing detection signal can be a square wave signal with a relatively long effective pulse width or a pulse signal with a relatively short effective pulse width.

[0085] Here, the zero-crossing detection module may detect only the first detection signal or only the second detection signal. To accommodate both the first and second detection signals output during the switching circuit's open or closed states, the detection circuit may have separate zero-crossing detection modules corresponding to the first and second detection signals, i.e., a first zero-crossing detection module and a second zero-crossing detection module. The circuit structure and operation of the first and second zero-crossing detection modules are as described above and will not be repeated here.

[0086] The detection circuit further includes a logic module that is connected to the output terminals of both the first zero-crossing detection module and the second zero-crossing detection module.

[0087] To prevent other logic devices in the zero-crossing detection circuit from malfunctioning due to voltage disturbances regarding the zero-crossing detection signal, please refer to the following examples in some cases. Figure 9 The diagram shows a schematic of a zero-crossing detection circuit. The logic module 566 in the circuit performs logical processing on the first and second zero-crossing detection signals output by the first and second zero-crossing detection modules 562 and 564 respectively, and outputs the zero-crossing detection signal. Examples of the logic module include XOR logic devices (groups), so that the zero-crossing detection signal is output only when the first or second zero-crossing detection module outputs a first or second zero-crossing detection signal indicating that the current AC current is in the zero-crossing phase interval.

[0088] In a zero-crossing detection circuit designed based on the technical solution provided in this application, the effective duration of the output zero-crossing detection signal can be very short, so short that control circuits in power-saving, standby, or sleep states may miss the response. Examples of such control circuits include circuits containing a CPU and circuits containing an enable controller. Therefore, the detection circuit of this application further includes a zero-crossing detection signal output module, which amplifies the zero-crossing detection signal output by the zero-crossing detection module or logic module. Here, the amplification process includes voltage amplitude amplification and / or effective duration amplification. In some examples, the zero-crossing detection signal output module includes an amplifier that amplifies the voltage amplitude of the zero-crossing detection signal to match the voltage requirements for waking up subsequent control circuits.

[0089] In some other examples, the zero-crossing detection signal output module extends the effective duration of the zero-crossing detection signal. Here, the zero-crossing detection signal output module converts the zero-crossing detection signal with an effective pulse width provided by the zero-crossing detection module into a zero-crossing detection signal with a preset duration; wherein the duration of the effective pulse width is less than the preset duration.

[0090] The zero-crossing detection signal output module includes a duration extension device (group), and may even include a trigger / reset device (group) for the duration extension device (group). Examples of the duration extension device (group) include a monostable multivibrator (also known as a one-shot). Examples of the trigger / reset device (group) for the duration extension device (group) include a timer, a trigger, etc. The trigger / reset device (group) outputs a trigger signal based on the zero-crossing detection signal provided by the zero-crossing detection module, and starts a reset timer based on the zero-crossing detection signal provided by the zero-crossing detection module, and outputs a reset signal when the reset timer times out. The duration extension device (group) outputs a zero-crossing detection signal based on the trigger signal and performs a reset based on the reset signal. The duration extension device (group) outputs the zero-crossing detection signal based on a preset duration to achieve the purpose of extending the duration. The preset duration can be a fixed value, or it can be determined based on the time interval between the trigger signal and the reset signal of the duration extension device (group).

[0091] Taking the zero-crossing detection signal output module receiving only the first zero-crossing detection signal provided by the first zero-crossing detection module as an example, if the first zero-crossing detection signal received by the trigger / reset device (group) is a pulse signal, then the trigger / reset device (group) outputs a trigger signal to trigger the duration extension device (group) to output a valid zero-crossing detection signal within a preset duration; wherein the preset duration is longer than the duration of the first zero-crossing detection signal; simultaneously, the trigger / reset device (group) performs a reset timing based on the first zero-crossing detection signal, and outputs a reset signal when the reset timing expires, so as to reset the duration extension device (group). The duration of the reset timing is greater than or equal to the preset duration provided by the duration extension device (group), and must be less than the power frequency period.

[0092] Taking the zero-crossing detection signal output module receiving only the second zero-crossing detection signal provided by the second zero-crossing detection module as an example, when the zero-crossing detection signal received by the duration extension device (group) from the second zero-crossing detection module is a pulse signal, the duration extension device (group) outputs a zero-crossing detection signal with an effective pulse width of a preset duration; wherein the preset duration is greater than the duration of the pulse signal (i.e., the duration of the effective pulse width) and less than the power frequency period. The duration extension device (group) automatically resets after outputting the zero-crossing detection signal with an effective pulse width of the preset duration.

[0093] Taking the zero-crossing detection signal output module, which includes the aforementioned logic modules, the first trigger / reset device (group) corresponding to the first zero-crossing detection module, the second trigger / reset device (group) corresponding to the second zero-crossing detection module, and the duration extension device (group) as an example, please refer to [link to relevant documentation]. Figure 17The diagram shows a schematic of the detection circuit in one embodiment of the zero-crossing detection circuit. The output of the first zero-crossing detection module is connected to a first trigger / reset device (group), the output of the second zero-crossing detection module is connected to a second trigger / reset device (group), the two inputs of the logic module are respectively connected to the first trigger / reset device (group) and the second trigger / reset device (group), and the output of the logic module is connected to the duration extension device (group). Here, during the period when the switching circuit is open, the second zero-crossing detection module does not output a second zero-crossing detection signal. Correspondingly, the output of the second trigger / reset device (group) is considered to output a second reset signal. When the first zero-crossing detection module outputs a first zero-crossing detection signal (e.g., ...), the second zero-crossing detection module outputs a second reset signal. When a pulse signal is received, the first trigger / reset device (group) outputs a first trigger signal to the logic module and starts a first reset timing. The logic module outputs a trigger logic signal corresponding to the first trigger signal according to the preset control logic of the first trigger signal, the first reset signal, the second trigger signal, and the second reset signal. The duration extension device (group) outputs a zero-crossing detection signal of a preset duration (i.e., a zero-crossing detection signal with an effective pulse width of a preset duration) based on the trigger logic signal. When the reset timing expires, the first trigger / reset device (group) outputs a first reset signal. The logic module outputs a reset logic signal corresponding to the first reset signal according to the control logic, and then the duration extension device (group) resets. During the conduction period of the switching circuit, the first zero-crossing detection module does not output the first zero-crossing detection signal. Correspondingly, the output terminal of the first trigger / reset device (group) is regarded as outputting the first reset signal. When the second zero-crossing detection module outputs the second zero-crossing detection signal (such as a pulse signal), the second trigger / reset device (group) outputs the second trigger signal to the logic module and starts the second reset timing. The logic module outputs the trigger logic signal corresponding to the second trigger signal according to the preset control logic of the first trigger signal, the first reset signal, the second trigger signal, and the second reset signal. The duration extension device (group) outputs the zero-crossing detection signal of the preset duration (i.e., the zero-crossing detection signal with an effective pulse width of the preset duration) based on the trigger logic signal. When the reset timing expires, the second trigger / reset device (group) outputs the second reset signal. The logic module outputs the reset logic signal corresponding to the second reset signal according to the control logic, and then the duration extension device (group) resets.

[0094] In some applications, the zero-crossing detection circuit also includes a power supply circuit for providing power to itself or other circuits. Here, the power supply circuit provides power during both the on and off states of the switching circuit. The power supply may be a terminal that outputs a power supply signal.

[0095] Therefore, to accommodate the zero-crossing detection circuit's ability to perform zero-crossing detection during the switching circuit's open state, the power supply circuit provides a new energizing loop for the AC line connected to the switching circuit via a rectifier circuit. This energizing loop is used during the switching circuit's open state to provide a power supply signal to the power source.

[0096] Please see Figure 10 The diagram shows a schematic of the circuit framework of the power supply circuit in one embodiment. The power supply circuit includes: a transformer circuit 61 and a power management circuit 62.

[0097] The transformer circuit 61 is connected to the rectifier circuit and is used to supply power to the power supply via the rectified electrical signal. The transformer circuit includes a primary-side input unit and a secondary-side output unit. The primary-side input unit and the secondary-side output unit each include a primary winding and a secondary winding based on the mutual inductance principle. The primary-side input unit is connected to the rectifier circuit, and the secondary-side output unit outputs the power supply. During the switching circuit's open state, the transformer circuit utilizes the mutual inductance principle of inductors to convert the rectified electrical signal into a power supply signal. The voltage of this power supply signal is equal to or slightly higher than the maximum value of the operating voltage of each power-consuming device. These power-consuming devices include those that operate according to a preset operating voltage, such as semiconductor devices like chips and power transistors, and relays.

[0098] Here, since the transformer circuit is used as a power supply when the switching circuit is off, and considering the certain degree of arbitrariness in the actual installation of the intelligent switch containing the power supply circuit, it is necessary to ensure that the transformer circuit has a high power conversion efficiency. This arbitrariness manifests in the order in which the switching circuit and the load are connected to the live wire; for example, the switching circuit may be connected to the live wire before the load, or after the load.

[0099] In an assembly structure where the load is connected to the live wire, during the period when the switching circuit is open, a current lower than the load's operating voltage is needed to form a power supply loop with the power supply circuit and ground to create an internal power supply loop. To prevent excessive current in this loop from causing abnormal load operation, the primary input unit and secondary output unit of the transformer circuit need to maximize energy conversion. Therefore, in some examples, the secondary output unit includes a secondary winding and a unidirectional conduction module. The output terminal of the secondary winding is connected to the unidirectional conduction module, and the unidirectional conduction module and the secondary winding are connected to a common ground, thereby maximizing the output of converted electrical energy from the secondary winding and improving the conversion efficiency of the transformer circuit. Here, the unidirectional conduction module prevents current backflow in the circuit containing the secondary winding. In some examples, the unidirectional conduction module includes a diode, and optionally a capacitor. See also... Figure 11The diagram shows a circuit structure schematic of a power supply circuit in one embodiment, wherein the unidirectional conduction module includes a diode D11 and a capacitor C11. The cathode of diode D11 is connected to one end of the secondary winding, and the anode is connected to one end of capacitor C11, forming the output terminal of the secondary output unit 612. The other end of capacitor C11 shares a common ground with the other end of the secondary winding. This allows the secondary winding to maximize the conversion of induced energy into electrical energy, which is then filtered by capacitor C11 and supplied to the power supply.

[0100] In order to control the transformer circuit to provide a stable power supply during the switching circuit being open, the power management circuit is at least connected to the primary-side input unit. The power management circuit is used to acquire a first sampling signal reflecting the power supply signal output by the power supply during the switching circuit being open, and to control the current flowing through the primary-side input unit based on the first sampling signal so that the power supply output by the secondary-side output unit is stable.

[0101] Here, the power management circuit can be formed by integrating discrete components on a PCB board, or by forming the power management circuit on a wafer using semiconductor processes and packaging it into a chip.

[0102] Here, to accurately reflect the fluctuations in the power supply signal, the power management circuit acquires the first sampling signal from the line where the secondary output unit is located. For example, the first sampling signal can come directly from the power supply signal output by the secondary output unit, directly reflecting the power supply signal. Alternatively, the first sampling signal comes from the power pin of an electrical device operating on power supplied by the power supply, such as the power pin of a CPU chip operating on power supplied by the power supply, which indirectly reflects the power supply signal provided by the secondary output unit using the standard power supply signal of the powered electrical device. Here, depending on the actual design of the sampling circuit for acquiring the first sampling signal, the first sampling signal can be a voltage signal or a current signal. For example, a current sampling device is used to acquire the current at the output terminal of the secondary output unit to obtain a current signal, i.e., the first sampling signal; the current flowing through the primary input unit is controlled based on the first sampling signal; or, when appropriate, a current-to-voltage device is used to convert the first sampling signal into a voltage signal, and the voltage signal is used to control the current flowing through the primary input unit. For example, a voltage sampling device is used to collect the voltage at the output terminal of the secondary output unit to obtain a voltage signal, namely the first sampling signal; the current flowing through the primary input unit is controlled based on the first sampling signal; or, when appropriate, a voltage-to-current device is used to convert the first sampling signal into a current signal, and the current signal is used to control the current flowing through the primary input unit.

[0103] In some examples, the power supply circuit further includes a first sampling circuit connected between the secondary output unit and the power management circuit. The first sampling circuit is used to sample the output side of the secondary output unit and obtain a first sampling signal. The first sampling circuit 64 includes voltage divider resistors R11 and R12 connected between the secondary output unit 612 and ground, and outputs the first sampling signal FB1 from the connection of resistors R11 and R12.

[0104] Here, the first sampling circuit can be configured independently and connected to a chip pin in the chip integrating the power management circuit. For example, the first sampling circuit can be externally mounted and connected to the first sampling pin of the chip containing the power management circuit and the output terminal of the secondary output unit, and the chip directly acquires the first sampled signal after voltage division. Alternatively, the first sampling circuit can be integrated with the power management circuit. For example, if the power management circuit and the first sampling circuit are integrated into a single chip, the first sampling pin of the chip is connected to the output terminal of the secondary output unit, and the first sampling circuit integrated inside the chip performs voltage division processing on the electrical signal acquired by the first sampling pin to obtain the first sampled signal after voltage division processing.

[0105] The power management circuit controls the current flowing through the primary input unit based on the first sampled signal. Here, during the off-state of the switching circuit, the power management circuit acts as a control circuit for the transformer circuit. It uses the voltage (or current) of the first sampled signal, which reflects the power supply, to control the current in the circuit containing the primary input unit of the transformer circuit. This changes the current flowing through the primary winding of the primary input unit, allowing the supply voltage of the secondary output power supply, converted via mutual inductance, to be maintained within a stable voltage range. For example, the power management circuit controls the change in current flowing through the primary winding by switching the circuit containing the primary input unit on and off based on the voltage of the first sampled signal.

[0106] In some implementations, to ensure AC power is available during the switching circuit's open state, the rectifier circuit includes a first rectifier unit connected to the AC line on the input side of the switching circuit and providing a first rectified electrical signal to the transformer circuit. The power management circuit includes a power management circuit electrically connected to the primary-side input unit, used to acquire the first sampling signal during the switching circuit's open state and control the current flowing through the primary-side input unit based on the first sampling signal.

[0107] Here, the power management circuit acquires a first sampling signal using any of the aforementioned examples and adjusts the current in the primary winding based on the voltage (or current) of the first sampling signal. For example... Figure 11As shown, the power management circuit includes an adjustment module 621 and a first control module 622. The adjustment module 621 is located on the line between the primary-side input unit 611 and ground, and is used to control the on / off state or current change of the line between the primary-side input unit 611 and ground. In one example, the adjustment module 621 includes a resistor and a controlled switch, which are connected in series between the primary winding and ground. Examples of the controlled switch include any one or a combination of a bipolar junction transistor (BJT), a junction field-effect transistor (JFET), a depletion-mode MOS power transistor, and a thyristor. In another example, the adjustment module 621 includes multiple selection lines and selectors connected between the primary-side input unit and ground, wherein each selection line has a resistor with a different resistance value, and the selector is controlled to switch to different selection lines, causing a corresponding change in the current flowing through the primary-side input unit. The selector includes, but is not limited to, switching devices. For example, the adjustment module includes two selection lines, one of which is a wire, and the other is equipped with a resistor and a switching device; by default, when the switching device is off, the primary-side input unit is grounded through the wire, and when the switching device is on, the primary-side input unit is grounded through the resistor.

[0108] Here, the first control module is connected to the adjustment module and is used to control the adjustment module based on the first sampling signal.

[0109] Specifically, the first control module is connected to the control terminal of the regulating module and controls the regulating module to switch on or off or regulate the current by detecting the first sampling signal. Therefore, the first control module includes a detection submodule and a control submodule. The detection submodule is used to output a detection signal by detecting the voltage of the first sampling signal; and the control submodule is used to control the regulating module based on the detection signal.

[0110] In some examples, the detection signal can be a logic signal reflecting a comparison between the voltage of the first sampled signal and a preset reference voltage. For this purpose, the detection submodule includes a comparison sub-circuit that compares the voltage of the first sampled signal with the preset reference voltage and outputs a detection signal based on the comparison result. The reference voltage can be a reference voltage range or a reference voltage value set based on the supply voltage of the power supply.

[0111] The comparator circuit utilizes analog devices of logic devices and auxiliary logic devices to represent the detection logic between the first sampled signal and the reference voltage, and outputs a corresponding detection signal. This detection signal is a logic signal that uses a level signal to represent the detection result. For example, when the voltage of the first sampled signal is higher than the reference voltage Vref, the detection signal outputs a high level; when the voltage of the first sampled signal is lower than the reference voltage Vref, the detection signal outputs a low level. In practice, according to the logical expression requirements of the logic signals between the comparator circuit and the control submodule, the comparator circuit includes logic devices such as comparators, inverters, flip-flops, AND gates, and NOT gates. Examples of comparators include hysteresis comparators or voltage comparators. Examples of flip-flops include D flip-flops.

[0112] It should be noted that the above method of using a single-level signal as a detection signal is only an example. In fact, the detection signal can be multiple logic signals. The control submodule uses the control type expressed by multiple logic signals to select the corresponding control method to control the adjustment module.

[0113] In other examples, the detection signal is an analog or digital signal reflecting the voltage difference between the voltage of the first detection signal and a preset reference voltage. For this purpose, the detection submodule includes a numerator circuit for generating an error signal representing the voltage difference between the voltage of the first sampled signal and the preset reference voltage, and outputting a detection signal based on the error signal. Here, the numerator circuit includes at least an error amplifier, examples of which include, but are not limited to, an error amplifier composed of transconductance and a filter capacitor, or an error amplifier including a subtractor, integrator, counter, and digital-to-analog converter. The numerator circuit may also include an amplifier connected to the output of the error amplifier to amplify the error voltage signal for fine control by the control submodule.

[0114] In fact, depending on whether the received detection signal is a logic signal or an error signal, the control submodule provides a corresponding circuit structure to control at least one of the switching frequency, on-time, and off-time of the regulating module; or to control the frequency of change of the regulating current of the regulating module. In some examples where the detection signal is a logic signal, taking the adjustment of the regulating module's on / off state as an example, the control submodule adjusts the duty cycle of its internal PWM signal based on the detection result of the supply voltage being too high or too low, thereby adjusting the ratio of the on-time and off-time of the regulating module, and thus adjusting the supply voltage output by the transformer circuit. In other examples where the detection signal is a logic signal, taking the adjustment of the regulating module's on / off state as an example, the control submodule adjusts the switching frequency of the regulating module based on the detection result of the supply voltage being too high or too low, thereby adjusting the supply voltage output by the transformer circuit. For example, the control submodule includes an adjustable frequency divider, which is adjusted according to the received detection signal to change the frequency of the control signal, and the switching frequency of the regulating module is controlled based on the changed frequency of the control signal. In some further examples where the detection signal is a logic signal, taking the adjustment of the current change of the regulating module as an example, the control submodule adjusts the duty cycle of the internal PWM signal based on the detection result indicating that the supply voltage is too high or too low, as represented by the detection signal. The duration of the high and low levels of the PWM signal corresponds to the duration of one selected circuit and the other selected circuit selected by the regulating module, respectively. The current regulation scheme provided in any of the above examples achieves the goal of stabilizing the supply voltage output by the transformer circuit.

[0115] In some examples where the detection signal is an error signal, taking the adjustment of the switching on / off state of the regulating module as an example, the control submodule contains a timer. The timer uses the voltage of the detection signal as a reference voltage and times at least one of the durations of the on-state and off-state of the regulating module. Then, based on the timeout signal generated at the corresponding timeout moment, it controls the regulating module to switch between the on-state and off-state. The timer can be exemplified as a timing circuit including a capacitor and its charging / discharging circuit; or as a timing circuit including a clock generator, a counter, and a digital-to-analog converter. In further examples where the detection signal is an error signal, taking the adjustment of the current change of the regulating module as an example, the control submodule adjusts the duty cycle of the internal PWM signal according to the error voltage represented by the detection signal. The durations of the high and low levels of the PWM signal correspond to the durations of one selected circuit and the other selected circuit selected by the regulating module, respectively. The current adjustment scheme provided by any of the above examples achieves the goal of stabilizing the supply voltage output by the transformer circuit.

[0116] Based on the above examples and... Figure 11For example, the working process of the transformer circuit and power management circuit in the power supply circuit is illustrated as follows: During the period when the switching circuit is open, the rectifier circuit outputs the first rectified electrical signal (corresponding to the rectified electrical signal in the figure) to the primary input unit 611 in the transformer circuit; using the mutual inductance principle, the primary and secondary windings in the transformer circuit perform energy conversion, and the secondary output unit 612 in the transformer circuit provides a power supply signal (voltage Vout1) to the power supply. The detection submodule in the first control module 622 acquires the first sampling circuit 64's sampled signal reflecting the power supply signal. A sampling signal FB1 is generated, and when the adjustment module 621 is turned on, the error voltage between the voltage of the first sampling signal FB1 and a preset reference voltage is used as a detection signal and output to the control submodule. The control submodule uses the voltage provided by the detection signal as the reference voltage for timing, sets the on-time of the timer adjustment module 621, and controls the adjustment module 621 to turn off and reset the timer when the timing expires; and when the adjustment module 621 is turned off, the timer is set to start timing for a preset fixed time, and controls the adjustment module 621 to turn on and reset the timer when the timing expires. This achieves the purpose of providing internal power to the power supply circuit using the transformer circuit during the period when the switching circuit is off.

[0117] In other embodiments, the power management circuit further acquires a third sampling signal reflecting the line electrical signal in the line where the primary-side input unit is located, and controls the current flowing through the primary-side input unit based on the first and third sampling signals. The first sampling signal reflects the power output information currently provided by the secondary-side output unit, and the third sampling signal reflects the energy input information currently provided by the primary-side input unit. The power management circuit controls the current in the line where the primary-side input unit is located based on these two sampling signals, which can improve the output stability of the power supply. The third sampling signal is acquired using a data acquisition device (group) connected to the primary-side input unit, and it can be a voltage or current signal.

[0118] In some examples, the power management circuit controls the line containing the primary-side input unit to be turned on (or off) based on the first sampling signal, and controls the line containing the primary-side input unit to be turned off (or on) based on the third sampling signal. In still other examples, the power management circuit controls the line containing the primary-side input unit to be turned on based on the first sampling signal, and controls the line containing the primary-side input unit to be turned off based on both the first and third sampling signals.

[0119] For some specific examples, please refer to Figure 12This diagram illustrates the circuit structure of a power management circuit in another embodiment. The power management circuit includes an adjustment module 621 and a second control module 625, and also includes a third sampling circuit 66. The third sampling circuit 66 collects the voltage or current signal of the line where the primary-side input unit is located. For example, the third sampling circuit 66 includes a controlled switch and a sampling resistor. The input terminal of the controlled switch is connected to the input terminal of the adjustment module 621, and the output terminal of the controlled switch is grounded through the sampling resistor. The control terminal of the controlled switch is connected to the control terminal of the adjustment module 621 to synchronously receive the control from the second control module 625. The adjustment module 621 is similar to the aforementioned... Figure 11 The circuit structure and execution process of the adjustment module 621 shown are the same or similar, and will not be described in detail here. The second control module 625 controls the adjustment module 621 to be turned on based on the first sampling signal FB1, and controls the adjustment module 621 to be turned off based on the first sampling signal FB1 and the third sampling signal CS. In some more specific examples, the second control module 625 controls the on-time of the adjustment module 621 based on the first sampling signal, and controls the off-time of the adjustment module 621 based on the first sampling signal FB1 and the third sampling signal CS. For example, the second control module 625 adjusts the response time for performing the corresponding turn-on or turn-off control operation by adjusting the frequency of the internal clock signal, so as to adjust the corresponding turn-on and turn-off times by changing the response time; and the second control module 625 determines the turn-on time by detecting the changes in electrical signals on both sides of the primary input unit and the secondary output unit, that is, by comparing the voltage between the third sampling signal CS and the COMP_CS signal obtained based on the first sampling signal, thereby adjusting the turn-off time; and the second control module 625 determines the turn-off time by monitoring the changes in electrical signals output by the secondary output unit, that is, by comparing the voltage of the first sampling signal FB1 with the preset reference voltage, thereby adjusting the turn-on time.

[0120] In other examples, the second control module includes an on control sub-circuit, an off control sub-circuit, and a control logic sub-circuit.

[0121] The on-control subcircuit detects the acquired first sampling signal and obtains a corresponding detection signal, and outputs a clock signal based on the voltage of the obtained detection signal; wherein the frequency of the clock signal is related to the voltage of the obtained detection signal. The off-control subcircuit compares the third sampling signal with the detection signal output by the on-control subcircuit and outputs the logic signal corresponding to the comparison result. The control logic subcircuit controls the adjustment module to be on or off based on the clock signal and the logic signal corresponding to the comparison result. In other words, while maintaining the adjustment module on, the control logic subcircuit monitors the first logic signal indicating that the adjustment module should be off based on the clock signal. The off-control subcircuit compares the third sampling signal with the detection signal output by the on-control subcircuit and outputs the logic signal corresponding to the comparison result to the control logic subcircuit. Specifically, when the logic signal corresponding to the comparison result represents a first logic signal that causes the adjustment module to disconnect, the control logic sub-circuit controls the adjustment module to disconnect based on the first logic signal and the clock signal; when the logic signal corresponding to the comparison result does not represent the first logic signal, the control logic sub-circuit controls the adjustment module to turn on based on a preset second logic signal and the clock signal.

[0122] Please see Figure 13 The diagram illustrates a circuit structure of a power management circuit in another embodiment, comprising a turn-on control subcircuit, a turn-off control subcircuit, and a control logic subcircuit. The turn-on control subcircuit performs low-pass filtering on the voltage of the acquired first sampled signal to obtain a detection signal COMP corresponding to the first sampled signal, and outputs a clock signal based on the voltage of the detection signal COMP; wherein the frequency of the clock signal is related to the voltage of the detection signal COMP. Using the clock signal as the clock reference for the control logic subcircuit to respond to received logic signals, the control logic subcircuit monitors a first logic signal indicating that the adjustment module should be turned off based on the clock signal while maintaining the adjustment module on. Simultaneously, the detection signal COMP is also directly output as COMP_CS to the turn-off control subcircuit, or processed according to a preset ratio and converted into COMP_CS before being output to the turn-off control subcircuit. The disconnection control subcircuit outputs the logic signal corresponding to the comparison result of the third sampling signal CS and COMP_CS to the control logic subcircuit; wherein, when the logic signal corresponding to the comparison result represents the first logic signal that causes the adjustment module to disconnect, the control logic subcircuit controls the adjustment module to disconnect based on the first logic signal and the clock signal; when the logic signal corresponding to the comparison result does not represent the first logic signal, the control logic subcircuit controls the adjustment module to turn on based on the preset second logic signal and the clock signal.

[0123] It should be noted that the on and off operations of the aforementioned adjustment module can also be replaced by switching operations between multiple lines. Each line has resistors of different resistance values ​​to change the current flowing through the primary-side input unit based on the first and second logic signals. Details will not be elaborated here.

[0124] Please see Figure 14 The diagram shows a circuit structure schematic of a power management circuit in another embodiment. The power management circuit includes a third protection module, an adjustment module, and a second control module. The adjustment module adjusts the current in the line containing the primary input unit by switching it on and off; this will not be described in detail here.

[0125] The second control module controls the adjustment module to be turned on and off accordingly. In some examples, Figure 14 The second control module 625 shown can be connected with Figure 13 The second control module 625' shown is similar, except that, Figure 14At least some of the electrical components in the second control module 625” shown switch between an inactive state and an active state based on the protection logic signal generated by the third protection module 624. The inactive state includes, but is not limited to: a state in which at least some electrical components are not responding to input signals under the enable control of the protection logic signal, or a state in which at least some electrical components are unable to operate under the power supply control of the protection logic signal. In some more specific examples, at least one of the conduction control sub-circuit, the disconnection control sub-circuit, and the control logic sub-circuit in the second control module 625” includes an enable terminal, through which the protection logic signal is received. The corresponding sub-circuit switches between an active state and an inactive state based on whether the protection logic signal is active or inactive, thereby causing the regulating module 621 to be controlled to conduct and disconnect during the period when all sub-circuits are in an active state; and the regulating module 621 to be controlled to disconnect during the period when at least one sub-circuit is in an inactive state. For example, the conduction control subcircuit includes an enable terminal and receives a protection logic signal. Controlled by the protection logic signal, when the conduction control submodule is in the working state, the conduction control subcircuit outputs a clock signal corresponding to the first sampled signal; when the conduction control submodule is in the non-working state, the conduction control subcircuit outputs no clock signal. As another example, the disconnection control subcircuit includes an enable terminal and receives a protection logic signal. Controlled by the protection logic signal, when the disconnection control subcircuit is in the working state, the disconnection control subcircuit outputs a corresponding logic signal based on the comparison result of the third sampled signal CS and COMP_CS; when the disconnection control submodule is in the non-working state, the disconnection control subcircuit maintains the output of a first logic signal indicating that the adjustment module is disconnected. For example, the control logic sub-circuit includes an enable terminal and receives a protection logic signal. Under the control of the protection logic signal, when the control logic sub-circuit is in the working state, the control logic sub-circuit controls the adjustment module to be disconnected or turned on based on the received first logic signal or second logic signal; when the control logic sub-circuit is in the non-working state, the control logic sub-circuit maintains the adjustment module disconnected.

[0126] The third protection module 624 is used to detect an electrical signal reflecting the power supply signal of the power supply, and to provide circuit protection for the power management circuit based on the detection result. The electrical signal reflecting the power supply signal can be the first sampling signal FB1, or the detection signal COMP provided by the conduction control sub-circuit. The third protection module 624 protects certain electrical components in the power management circuit by detecting the first sampling signal FB1 or the detection signal COMP, so that the line containing the primary-side input unit is disconnected during the protection period. Here, the third protection module 624 determines whether the power supply is overvoltage and / or overloaded by detecting the voltage or current of the first sampling signal FB1 or the detection signal COMP, and outputs a protection logic signal corresponding to the detection result. In some examples, during periods when the power supply is under light load, the third protection module 624 detects whether the first sampling signal is higher than a preset overvoltage protection threshold. If so, it outputs a valid first protection logic signal, causing the sub-circuit in the corresponding second control module 625” to enter a non-operating state based on the valid first protection logic signal. The third protection module 624 outputs an invalid first protection logic signal based on the detection result of the first sampling signal in real time and the preset overvoltage reset logic, thereby restoring the second control module 625” to the operating state. Examples of the overvoltage reset logic include at least one of the following: a reset logic set based on the detection result, and a reset logic set based on a preset timing duration. Examples of the reset logic set based on the detection result include continuous signal detection, and outputting an invalid first protection logic signal once the detection result changes. Examples of the reset logic set based on the preset timing duration include starting a timer when the protection logic signal is valid, and outputting an invalid first protection logic signal when the timer reaches a preset timing threshold. In some other examples, during periods of heavy load on the power supply, the third protection module 624 detects whether the first sampling signal is lower than a preset overload protection threshold. If so, it outputs a valid second protection logic signal, causing the sub-circuit in the corresponding second control module 625” to enter a non-operating state based on the valid second protection logic signal. The third protection module 624 outputs an invalid second protection logic signal based on the detection result of the first sampling signal in real time and the preset overload reset logic, thereby restoring the second control module 125” to the operating state. Examples of the overload reset logic include at least one of the following: a reset logic set based on the detection result, or a reset logic set based on a preset timing duration. Examples of the reset logic set based on the detection result include continuous signal detection, and outputting an invalid second protection logic signal once the detection result changes.Examples of reset logic based on a preset timing duration include starting the timing when the protection logic signal is valid, and outputting an invalid second protection logic signal when the timing reaches a preset timing threshold.

[0127] It should be noted that the protection threshold and detection logic set by the third protection module should be related to the signals obtained from the actual circuit structure, rather than being limited to the examples mentioned above. For instance, the third protection module detects the voltage of the detection signal COMP, and when the voltage of the detection signal COMP is detected to be lower than a preset overvoltage protection threshold, it determines to output the first protection logic signal, thereby enabling the chip containing the power management circuit to be in standby mode and / or effectively maintaining the chip's power supply capability. These will not be elaborated upon further here.

[0128] In other examples, the protection logic signal generated by the third protection module controls the regulating module to remain in an open state (not shown). For example, the third protection module is connected to the control terminal of a switch in the regulating module, and the corresponding switch remains open while the third protection module outputs a protection logic signal.

[0129] In some practical circuits, the power management circuit is presented as a chip. For details on chip integration, please refer to [link / reference needed]. Figure 3 The diagram shows a circuit structure schematic of a power supply circuit in one embodiment, where the first self-powered circuit 65 can be externally connected between the secondary output unit 612 and the power supply pin VCC of the zero-crossing detection circuit. Alternatively, at least some components of the first self-powered circuit can be integrated into the chip containing the zero-crossing detection circuit. For example, the diodes and / or voltage divider resistors in the first self-powered circuit can be integrated into the zero-crossing detection circuit. Or, the entire first self-powered circuit can be integrated into the chip containing the zero-crossing detection circuit.

[0130] To enable rapid power supply to the chip when the switching circuit is off, some practical circuits include a startup power supply circuit to provide startup power to the power management circuit. This startup power supply includes providing a reference voltage and a chip startup voltage to the power management circuit. In some examples, the startup power supply circuit includes a capacitor and a charging unit for the capacitor. The charging unit utilizes the voltage variation of the rectified signal provided by the rectifier circuit to generate a charging power supply for the capacitor until it is charged and reaches the startup voltage, thus enabling chip startup.

[0131] During the conduction of the switching circuit, the power supply circuit can still provide internal power. To this end, utilizing the circuit structure provided by the selection circuit and the second detection signal generation module in the zero-crossing detection circuit, the power management circuit further includes an output module for continuously providing power based on the received second rectified electrical signal. In some examples, depending on the voltage range of the rectified electrical signal (hereinafter referred to as the second rectified electrical signal) output by the rectifier circuit, the output module can directly output the second rectified electrical signal to the output terminal of the power supply. For example, the output module is a wire. In other examples, the output module includes at least one of a filter capacitor and a voltage divider resistor to match the voltage of the provided power supply signal with the required supply voltage of the power supply. In still other examples, the power management circuit further includes a second protection module for providing overcurrent protection to the power supply. For example, the second protection module includes a protection resistor disposed between the rectifier circuit and the output terminal of the power supply, and a comparator OCP for detecting the voltage difference across the protection resistor. Specifically, when the comparator OCP detects that the voltage difference across the protection resistor exceeds a preset protection voltage threshold, it determines that an anomaly has occurred and outputs an overcurrent protection detection signal, which allows some control circuits to perform forced control operations on the switching circuit. The second protection module may also be composed of other circuits including transistors and / or triodes, which will not be listed here.

[0132] It should be noted that the examples of the above output modules are not mutually exclusive and can be used in combination according to the actual circuit design. Moreover, for the purpose of circuit optimization, the electrical components mentioned in the foregoing examples can also serve the functions of the rectifier circuit and the zero-crossing detection circuit. For example, the filter capacitor can be shared with the capacitor in the rectifier circuit. Here, those skilled in the art should understand the electrical components described in the examples of this application from the perspective of the role of the circuit components in the circuit structure.

[0133] The power supply circuit further includes a second self-powered circuit for supplying power to the zero-crossing detection circuit during the conduction of the switching circuit. In some examples, the zero-crossing detection circuit is integrated into a chip, and the second self-powered circuit is connected between the output terminal of the power supply and the power supply terminal of the chip. For example, the second self-powered circuit may be a wire connected to the power supply and the power supply terminal of the zero-crossing detection circuit. Alternatively, depending on the actual operating voltage of the power management circuit, the second self-powered circuit may also include at least one of the following: a voltage divider resistor, a low-dropout linear regulator, etc., connected between the output terminal of the power supply and the power supply terminal of the chip. In other examples, the input terminal of the second self-powered circuit is connected to a second line, and its output terminal is electrically connected to the power supply terminal of the zero-crossing detection circuit; or the input terminal of the second self-powered circuit is connected to the output terminal of a rectifier circuit disposed in the second line, and its output terminal is electrically connected to the power supply terminal of the zero-crossing detection circuit.

[0134] For example, during the conduction period of the switching circuit, the second self-powered circuit draws power from the second line and converts it to supply the chip; during the discontinuation period of the switching circuit, the first self-powered circuit draws power from the output of the power supply and converts it to supply the chip.

[0135] Based on the circuit structure of the zero-crossing detection circuit described above, this application also provides a chip. The chip includes at least the following pins: a first pin for acquiring an electrical signal reflecting an AC signal; a ground pin for connecting to ground; and a power supply pin, etc. In some applications, the zero-crossing detection signal provided by the zero-crossing detection circuit can be output through another pin of the chip, that is, the chip also includes a signal output pin for outputting the zero-crossing detection signal.

[0136] The first pin can be directly connected to an AC power line, and the electrical signal obtained through the first pin is an AC signal; or the first pin can be connected to a rectifier circuit, and the electrical signal obtained through the first pin is a rectified AC signal. Either of these electrical signals at least reflects an AC signal within a preset zero-crossing phase interval.

[0137] In some embodiments, some or all of the electrical components in the first detection signal generation module of the zero-crossing detection circuit are integrated into the chip. The circuit structure and operation of the first detection signal generation module are the same as or similar to those of the aforementioned first detection signal generation module, and will not be described in detail here. In some examples, at least some of the electrical components in the sampling submodule of the first detection signal generation module are integrated into the chip. In some examples, the chip can be a circuit structure formed and packaged on a wafer using semiconductor technology. For example, the switches and voltage divider resistors in the sampling submodule are integrated into the chip and connected to the rectifier bridge via the first pin. In still other examples, the chip can be a circuit structure formed by integrating discrete components on a PCB board and packaging them. For example, the zero-crossing detection circuit including the sampling submodule is packaged together on a PCB board to form a chip, and the first pin of this chip can serve as the input terminal of the rectifier bridge in the sampling submodule, connected to the AC power line.

[0138] Taking the zero-crossing phase of the AC power supply detected by the first detection signal generation module during the off-state of a switching circuit on an AC power line as an example, the AC power line is connected between the switching circuit and the live wire of the urban power grid, such that the AC power line, the first detection signal generation module, and the voltage ground form a current-carrying loop for the AC power supply during the off-state of the switching circuit. Thus, the first detection signal generation module obtains the AC power signal on the AC power line through its first pin.

[0139] In some embodiments, the chip further includes a second pin for accessing an AC power line. In some embodiments, this second pin may be shared with the first pin; for example, both may be connected to the AC power line between the switching circuit and the live wire via the first pin, so that an AC signal can be obtained both when the switching circuit is on and off. In still other embodiments, the second pin is connected to the AC power line between the switching circuit and the neutral wire, so that an AC signal is obtained only when the switching circuit is on.

[0140] In order to enable zero-crossing detection during the conduction of the switching circuit, depending on the chip's package design, in some examples, the chip intermittently acquires electrical signals reflecting the AC signal through line selection by a selection circuit. In some more specific examples, the selection circuit connects the switching circuit to a first line or a second line, wherein the chip is connected to the second line via a chip pin. The selection circuit switches to the second line when the AC phase is close to the zero-crossing phase interval, and switches to the first line in other phase intervals. The second detection signal generation module outputs a corresponding second zero-crossing detection signal based on the detection of the electrical signal reflecting the AC signal acquired from the second line via the chip pin. Here, the circuit structure and operation of the second detection signal generation module can be as described above, and will not be detailed here. In some other examples, the selection circuit can also be packaged in the chip. In still other examples, the chip also has chip pins connected to the selection circuit for outputting a shunt control signal to the selection circuit, whereby the shunt control signal is used by the selection circuit to perform a switching operation immediately or with a delay.

[0141] The selection circuit shown in any of the above examples has the same or similar circuit structure and operation process as the selection circuit mentioned in the aforementioned zero-crossing detection circuit, and will not be described in detail here.

[0142] To generate the shunt control signal, the detection signal generation circuit further includes a shunt control module connected to the selection circuit. This module outputs a shunt control signal to the selection circuit by detecting the second sampling signal or a zero-crossing detection signal, thereby controlling the selection circuit to switch between the first line and the second line. Here, the circuit structure and operation of the shunt control module are the same as or similar to those of the shunt control module in the aforementioned zero-crossing detection circuit, and will not be described in detail here.

[0143] In some embodiments, the detection signal generation circuit further includes a first protection module, used to detect the voltage of the second sampled signal, and when the voltage of the second sampled signal is higher than a preset protection voltage threshold, control the selection circuit to switch from the second line to the first line. Here, the circuit structure and operation of the first protection module are the same as or similar to the first protection module in the aforementioned zero-crossing detection circuit, and will not be described in detail here.

[0144] The chip also integrates a detection circuit, which performs zero-crossing detection on the detection signal output by the detection signal generation circuit to output a zero-crossing detection signal. The circuit structure and operation of this detection circuit are the same as or similar to the aforementioned zero-crossing detection circuit, and will not be detailed here. Depending on the electrical components in the actual integrated detection circuit, the chip may include at least one chip pin for outputting a zero-crossing detection signal. For example, the chip may include two chip pins for outputting the zero-crossing detection signal, one outputting the signal during the switching circuit's off-state and the other during the switching circuit's on-state. Alternatively, the chip may include a single chip pin that outputs a zero-crossing detection signal during both the on and off-state of the switching circuit. The output zero-crossing detection signal may be provided by a zero-crossing detection module, logic module, or zero-crossing detection signal output module within the detection circuit, and will not be detailed here.

[0145] In some applications, the chip may also integrate some electrical components from a power supply circuit. This power supply circuit includes electrical components or circuit modules that are the same as or similar to those mentioned above, and will not be detailed further here. For example, the chip's pins may also include pins for connecting to a transformer circuit, pins for acquiring a first sampling signal, and pins for connecting to a power supply. The power supply circuit within the chip provides power to the chip itself, and even to switching circuits and control circuits that can perform control operations based on the zero-crossing detection signal, through the corresponding pins.

[0146] This application also provides a smart switch. To prevent damage to the load caused by transient high voltage affecting the semiconductor devices and the smart switch itself when the load is powered on or off within the peak AC voltage range, the smart switch includes: a switching circuit, a zero-crossing detection circuit, and a control circuit.

[0147] The switching circuit is connected to the AC power line where the load is located and is controlled to be turned on or off. In some examples, the switching circuit includes a relay, which is powered by a power supply. The switch terminals of the relay are connected to the AC power line, and the control terminal is connected to the control circuit. Here, the control circuit can turn the relay on by increasing the supply current to the relay control terminal; and the control circuit can turn the relay off by decreasing the supply current to the relay control terminal.

[0148] The zero-crossing detection circuit detects the zero-crossing phase of the AC current by detecting the AC power line connected to the switching circuit, and outputs a zero-crossing detection signal. Further details are omitted here.

[0149] The control circuit is connected to the zero-crossing detection circuit and is used to control the switching circuit to be turned on or off based on the zero-crossing detection signal and the received control information.

[0150] Therefore, the control circuit includes an interaction unit and a processing unit (not shown). The interaction unit is used to acquire control information; the processing unit is connected to the interaction unit and is used to control at least the switching circuit to be turned on or off based on the control information.

[0151] In some examples, the interaction unit may include a human-computer interaction module for receiving user operations to obtain the control information. The human-computer interaction module may include, for example, an interaction panel with a touch medium, including but not limited to: a touchscreen, a button, a photosensitive device, etc. In other examples, the interaction unit may include a communication module for receiving and transmitting wireless signals containing control information. The communication module may include at least one of the following: short-range communication modules such as RF communication modules, WiFi communication modules, infrared communication modules, and Bluetooth communication modules; wide area network communication modules capable of accessing fiber optics, broadband, etc.; and communication modules that utilize a SIM card to access mobile networks, etc. The above examples may be combined or configured individually in the interaction unit. For example, the interaction unit includes a button for controlling a switching circuit and a wireless communication module for acquiring wireless signals. The interaction unit determines that it has received control information for turning on the switching circuit by monitoring the pulse signal generated by the button, and the interaction unit acquires the carried control information by demodulating and decoding the wireless signal. Here, the control information acquired using the wireless communication module may include control information for turning on the switching circuit, control information for controlling the switching circuits on other lines, and control information for controlling smart appliances to adjust, switch on, etc. The interaction unit provides the obtained control information to the processing unit, which converts the control information into control signals recognizable by the corresponding electrical device or switching circuit and outputs them.

[0152] Here, the processing unit includes processing modules capable of handling numerical operations, logical operations, and data processing, such as MCUs, CPUs, and programmable logic devices. Depending on the pin functions of the chip that packages the corresponding processing module, the processing unit can be electrically connected to a switching circuit or communicate via an interaction unit. Powered by the transformer circuit, the processing unit analyzes the received control information while the switching circuit is open to determine the controlled object and the timing of control execution. The processing unit may also include hardware modules such as timers, clock signal generators, and buffers to assist the processing module in performing corresponding control operations.

[0153] Here, the control circuit can perform the control operation of turning the switch circuit on when the switch circuit is off, or it can perform the control operation of turning the switch circuit off when the switch circuit is on.

[0154] Please see Figure 15 The diagram shows a circuit structure schematic of a smart switch in one embodiment. Taking the output of a zero-crossing detection signal by the first detection signal generation module and the first zero-crossing detection module in the aforementioned zero-crossing detection circuit during the switch circuit's open state as an example, the working process of the smart switch is described as follows: (Combined with...) Figure 15During the period when the switching circuit is open, the first rectifier unit 521, transformer circuit 531 and power management circuit 532 in the smart switch provide power to the electrical components inside the smart switch, which will not be described in detail here. Under stable power supply, the first detection signal generation module 561 directly acquires the AC signal flowing to the first rectifier unit 521 during the period when the switch circuit 51 is open to obtain the first detection signal; the control submodule 565 in the first detection signal generation module controls the acquisition submodule 561 to generate the first detection signal, for example, the control submodule 565 controls the acquisition submodule 561 to generate the first detection signal according to a preset time interval; the first zero-crossing detection module 562 detects the voltage of the first detection signal during each acquisition period to determine whether the phase of the current AC power is within the zero-crossing phase interval, and outputs the zero-crossing detection signal according to the detection result; wherein, when it is determined by detection that the phase of the current AC power does not fall within the zero-crossing phase interval, the control submodule 565 does not adjust the acquisition time interval, and when it is determined by detection that the phase of the current AC power falls within the zero-crossing phase interval, the control submodule 565 adjusts the acquisition time interval to extend the acquisition duration. The control circuit 536 receives the zero-crossing detection signal and generates a delay timer for the control information based on the preset response delay of the switching circuit and the zero-crossing detection signal. When the control circuit 536 receives the control information to turn on the switching circuit, it starts the delay timer until it receives the zero-crossing detection signal indicating that the phase of the current AC power is within the zero-crossing phase interval, and then controls the switching circuit 51 to turn on.

[0155] Taking the second zero-crossing detection unit in the aforementioned zero-crossing detection circuit as an example during the conduction period of the switching circuit, the working process of the smart switch is described as follows: (Combined with...) Figure 15 During the conduction period of the switching circuit, the second rectifier unit 522 and the power management circuit in the smart switch provide power to the internal electrical components of the smart switch, which will not be described in detail here. Under the stable power supply, the second detection signal generation module 563 collects the second rectified electrical signal to obtain the second detection signal, and the second zero-crossing detection module 564 detects the voltage of the second detection signal to determine whether the phase of the current AC power is within the zero-crossing phase interval, and outputs the zero-crossing detection signal according to the detection result. The control circuit 536 receives the zero-crossing detection signal and generates a delay timer for the control information based on the preset response delay of the switching circuit 51 and the zero-crossing detection signal. When the control circuit 536 receives the control information to turn on the switching circuit 51, it starts the delay timer until it receives the zero-crossing detection signal indicating that the phase of the current AC power is within the zero-crossing phase interval, and then controls the switching circuit 51 to turn on.

[0156] It should be noted that, since the second rectifier unit outputs the second rectified electrical signal in the preset reference phase interval, in order to take into account both the zero-crossing detection signal and the power supply, the voltage interval corresponding to the reference phase interval can cover the zero-crossing voltage interval, thereby ensuring that during the period when the second rectifier unit outputs the second rectified electrical signal, the corresponding second zero-crossing detection unit can output the second zero-crossing detection signal.

[0157] In some practical applications, when a load is powered on or off within the peak AC voltage range, the semiconductor devices and switching circuits in the load are easily damaged by the instantaneous high voltage, causing load damage. Therefore, the smart switch mentioned in this application also integrates a zero-crossing detection circuit to detect the phase of the current AC signal based on the zero-crossing phase interval and output a zero-crossing detection signal to the control circuit. The control circuit then controls the switching circuit to turn on or off based on the zero-crossing detection signal and upon receiving control information. The control signal can be obtained based on control logic processing of at least one logic signal. The sources of the logic signal include, but are not limited to: on / off commands issued by wireless devices such as remote controls and smart terminals; mechanical on / off operations; electrical signals emitted by a touch panel; detection of the zero-crossing detection signal; or other devices including timers. The control circuit outputs the control signal based on preset control logic for at least one of the above logic signals.

[0158] In some examples, the control circuit can be triggered by a zero-crossing detection signal generated after receiving control information to control the switching circuit to turn on or off. In another example, the control circuit presets a response time for the switching circuit, wherein the response time is related to the time taken for a mechanical switching device selected in the switching circuit to perform an on or off operation, such as the response time of a relay. The control circuit generates a response timer based on the zero-crossing detection signal, and controls the switching circuit to turn on or off when the response timer expires and the control information is received. For example, the control circuit determines the duration and start time of the response timer based on the time interval of the most recently received zero-crossing detection signals and the preset response timer, and controls the switching circuit to perform an on / off operation when control information is received and the response timer expires. In another example, the control circuit determines the response timer based on multiple acquired zero-crossing detection signals, and controls the switching circuit to turn on or off based on the response timer expiration, the received control information, and the zero-crossing detection signal. Specifically, the control circuit predicts the time interval of subsequent zero-crossing detection signals by analyzing the time intervals of multiple zero-crossing detection signals, thus determining the response timing. Based on the response timing timeout, the received control information, and the zero-crossing detection signals, the circuit controls the switching circuit to turn on or off. For example, the time intervals of multiple consecutively received zero-crossing detection signals are recorded, and abnormal time intervals, such as those that are too long or too short, are eliminated. The average time interval of the zero-crossing detection signals is calculated. Based on this average time interval and the response time of the switching circuit, the timing for controlling the switching circuit to turn on or off when the AC phase approaches zero is predicted, and a corresponding response timing is started. When control information for controlling the switching circuit is received during this response timing period, the response timing times out. Based on the response timeout, the corresponding control operation is executed; otherwise, the response timing is reset, the timing for the next possible execution of the control operation is calculated, and the corresponding timing is started again.

[0159] In some embodiments, the smart switch further includes a rectifier circuit and a power supply circuit. The rectifier circuit is connected to the switch circuit and is used to rectify the applied AC power and output a rectified signal during both the open and closed periods of the switch circuit. The rectified signal output by the rectifier circuit can be a rectified signal obtained by rectifying the AC signal via a half-wave rectifier bridge or a full-wave rectifier bridge. To continuously output the rectified signal during both the open and closed periods of the switch circuit, the rectifier circuit can be connected to the live wire on one side of the switch circuit input terminal, so that the AC signal can be shunted to obtain a rectified signal during both the open and closed periods of the switch circuit.

[0160] In some implementations, such as Figure 15As shown, the rectifier circuit includes a first rectifier unit 521. The first rectifier unit 521 is connected to the AC power line connected to the input terminal of the switching circuit, and is used to rectify the AC power flowing to the switching circuit and output a first rectified electrical signal; wherein, the first rectified electrical signal is a rectified electrical signal provided by the rectifier circuit.

[0161] To ensure the load remains stationary during the disconnection of the switching circuit, the voltage range of the AC signal received by the first rectifier unit should be lower than the operating voltage range required for the load to operate. Technicians can ensure the load remains stationary when the first rectifier unit outputs the first rectified signal by selecting the component parameters in the first rectifier unit. In some examples, the first rectifier unit includes a rectifier bridge and a filter capacitor. Examples of the rectifier bridge include a half-wave rectifier bridge or a full-wave rectifier bridge. Taking a half-wave rectifier bridge as an example, the output terminal of the rectifier bridge in the first rectifier unit 521 is connected to a filter capacitor, and the other end of the filter capacitor is grounded.

[0162] The first rectified electrical signal output from the first rectifier unit is transmitted to the transformer circuit in the power supply circuit. The power management circuit can control the transformer circuit to convert the received first rectified electrical signal into energy according to any of the examples mentioned above, so as to obtain a power supply for supplying power to the internal electrical components of the intelligent switch such as the power management circuit, control circuit, and switching circuit.

[0163] by Figure 15 Taking the circuit structure of the intelligent switch shown as an example, the circuit structure and working process of the first rectifier unit 521 and the power management circuit 532 are illustrated as follows: The half-wave rectifier bridge of the first rectifier unit 521 is connected to the live wire of the input terminal of the switch circuit. The output terminal of the half-wave rectifier bridge is connected to the primary input unit in the transformer circuit 531 via a filter capacitor. Utilizing the transformer processing of the primary input unit and the secondary output unit, the secondary output unit outputs a power supply signal as the power supply output terminal. The primary input unit is grounded through the power management circuit. The secondary output unit is also grounded to reduce internal losses during energy conversion. The power management circuit includes a grounded adjustment module 541 and a second control module 542' for controlling the on / off state of the adjustment module 541. The secondary output unit includes a secondary winding grounded to voltage and a unidirectional conduction module connected to the output terminal of the secondary winding. A first sampling circuit 533 is provided on the power supply side of the secondary output unit. It collects the power supply voltage of the power supply and generates a first sampling signal FB1, and transmits the first sampling signal to the second control module 542'. At the same time, the second control module 542' also obtains the third sampling signal CS collected from the primary input unit through the third sampling circuit 552.

[0164] The working process of the above circuit structure is illustrated below: During the off-state of the switching circuit, the AC signal is half-wave rectified and low-pass filtered by the rectifier diodes in the first rectifier unit 521, and then output as the first rectified signal to the transformer circuit. The mutual inductance windings in the primary input unit and secondary output unit of the transformer circuit 531 transform the first rectified signal. Since the secondary winding in the secondary output unit is grounded, the diodes and capacitors in the unidirectional conduction module ensure that the converted power supply is output unidirectionally and stably. The second control module 542' controls the on / off state of the adjustment module 541 by detecting the first sampling signal FB1 and the third sampling signal CS. Specifically, the second control module 542' performs error amplification and / or low-pass filtering on the voltage of the acquired first sampling signal to obtain a detection signal COMP corresponding to the first sampling signal, and outputs a clock signal based on the voltage of the detection signal COMP, wherein the frequency of the clock signal is related to the voltage of the detection signal COMP. Meanwhile, the detection signal COMP is either directly used as COMP_CS, or processed according to a preset ratio and converted into COMP_CS for comparison with the third sampling signal CS, and a corresponding logic signal is generated based on the comparison result. The power management circuit sets the maximum conduction time of the adjustment module. The power management circuit controls the adjustment module to conduct according to the clock signal and starts timing at the conduction time. When the comparison result obtained by the second control module 542' through comparing CS and COMP_CS indicates that the adjustment module 541 should be disconnected, the adjustment module 541 is controlled to be disconnected, and the timing is reset. If the adjustment module is not turned off before the maximum conduction time is reached, the adjustment module is turned off when the timing ends.

[0165] It should be noted that, Figure 15 The description is for illustrative purposes only; in fact, according to Figure 11 The connection relationship and working process of the first control module and the adjustment module described therein can also achieve a control method similar to that of the second control module, which will not be described in detail here. Furthermore, according to... Figure 15 The second control module and the third protection module described therein can not only achieve stable power supply to the secondary output unit by controlling the adjustment module with the second control module, but also provide circuit protection for the normal operation of the internal electrical components with the third protection module, which will not be described in detail here.

[0166] The rectifier circuit also includes a second rectifier unit 522, which is connected to the live wire connected to the output terminal of the switching circuit 51. For example, the second rectifier unit 522 and the aforementioned first rectifier unit 521 are respectively located at opposite ends of the switching circuit 51. The second rectifier unit 522 is used to rectify the input AC signal and output a second rectified signal during the conduction period of the switching circuit 51. The second rectifier unit 522 includes a rectifier bridge and a filter capacitor. The rectifier bridge may include, for example, a half-wave rectifier bridge or a full-wave rectifier bridge. The filter capacitor is connected between the output terminal of the rectifier bridge and ground to perform low-pass filtering on the rectified signal output by the rectifier bridge to obtain the second rectified signal. The second rectified signal is another rectified signal provided by the rectifier circuit.

[0167] During the conduction period of the switching circuit, in order to ensure continuous power supply to the zero-crossing detection circuit, the power supply circuit switches the switching circuit and load between the first and second lines in a time-division manner, so that the second rectifier unit rectifies the received AC signal and outputs a corresponding second rectified signal. For example... Figure 15 As shown, the power supply circuit includes a selection circuit 535 disposed on the AC power line. Correspondingly, the power management circuit includes a phase-cutting control module 545 to control the selection circuit 535. The selection circuit 535 is connected to the second line by default. When the phase-cutting control module 545 detects that the voltage of the second rectified signal exceeds a preset voltage range, it controls the selection circuit 535 to switch from the second line to the first line. After a delay, the phase-cutting control module 545 adjusts the branch control signal to control the selection circuit 535 to switch from the first line to the second line. The duration of the delay is related to the duration for which the energy storage circuit maintains the supply voltage. The output module 543 outputs a supply signal to the energy storage circuit 540 during the period when the selection circuit switches to the second line, so that the power supply line 540 maintains the output supply signal during the period when the selection circuit switches to the first line. Correspondingly, the control circuit 536 can monitor control information in real time under the power supply, and when it detects and acquires control information, it executes corresponding control operations according to the content of the control information. For example, when the control circuit 536 receives a control message indicating that the control switch circuit 51 is turned on, it controls the switch circuit 51 to turn on.

[0168] In some cases, the first protection module 546 can also be used in a power management circuit that includes an output module. It is connected in parallel with the phase-cutting control module 545. When the voltage of the second sampling signal provided by the output terminal of the second sampling circuit is greater than the preset protection voltage threshold, the first protection module 546 controls the selection circuit 535 to switch from the second line to the first line. At the same time or with a slight delay, the phase-cutting control module 545 controls the selection circuit 535 to switch from the second line to the first line and maintains the switch for the specified duration.

[0169] During the conduction period of the switching circuit, the control circuit 536 in the smart switch can perform control operations similar to those during the de-energization period of the switching circuit 51, using the continuous power supply of the power management circuit 532. For example, it can perform control operations such as adjusting the air conditioner temperature, timing the start / stop of electronic devices, and disconnecting the switching circuit. Further details are omitted here.

[0170] This application also provides a zero-crossing detection method. Please refer to [link / reference]. Figure 16 The diagram shows a flowchart of a zero-crossing detection method in one embodiment. The zero-crossing detection method can be executed by a zero-crossing detection circuit. The zero-crossing detection circuit can be any of the zero-crossing detection circuits mentioned above, or any zero-crossing detection circuit capable of implementing the zero-crossing detection method.

[0171] In step S110, detection signals reflecting alternating current signals are generated at intervals; wherein the detection signals reflect at least the alternating current signals within a preset zero-crossing phase interval.

[0172] To reduce the internal losses of the zero-crossing detection circuit, it employs intermittent sampling or intermittent detection to generate a detection signal reflecting the AC signal. The intermittent generation of the detection signal means that the detection signal is not synchronized with the AC signal in real time. (See also...) Figure 2 It shows the correspondence between the waveforms of the generated interval detection signal and the AC signal. During the period when the detection signal is generated (or the detection signal is valid) T1, the waveform of the detection signal basically reflects the waveform of the AC signal or the AC signal after rectification. During the period when the detection signal is not generated (or the detection signal is invalid) T2, the waveform of the detection signal is independent of the waveform of the AC signal or the AC signal after rectification.

[0173] In some embodiments, step S110 may include generating a first detection signal reflecting the AC signal through an interval acquisition operation within one power frequency cycle of the AC current, wherein the first detection signal is one of the aforementioned detection signals. This step may be performed by the aforementioned first detection signal generation module. The circuit structure and operation of the first detection signal generation module are as described in the previous section on zero-crossing detection circuits, and will not be detailed here.

[0174] According to the circuit description of the first detection signal generation module, step S110 includes: performing a data acquisition operation based on a sampling control signal and generating a first detection signal to reflect the AC signal; and generating the output sampling control signal by detecting the first detection signal or a zero-crossing detection signal.

[0175] In some examples, this step can be performed by the sampling submodule and control submodule in the first detection signal generation module, which will not be described in detail here.

[0176] Under the coordinated execution of the sampling submodule and the control submodule, when the voltage of the first detection signal is detected to fall within a preset reference voltage range, step S110 further includes any one of the following steps: 1) ensuring that the sampling control signal is always effective within the reference voltage range; or 2) adjusting at least one of the duty cycle and frequency of the sampling control signal. The reference voltage range covers the zero-crossing voltage range corresponding to the zero-crossing phase range. When the voltage of the first detection signal is detected to not fall within the preset reference voltage range, the step further includes outputting the sampling control signal at preset intervals.

[0177] Taking a sampling submodule including a rectifier bridge RB3, a switch M2, and a sampling resistor HV_Resistor as an example, the control submodule 412 controls the switch M2 to be turned on or off. To this end, the control submodule 412 is connected to the control terminal of the switch M2 and outputs a sampling control signal by detecting the first detection signal to control the switch M2. Here, to ensure that the sampling submodule 411 can acquire the second sampling signal falling within the zero-crossing phase interval, the control submodule 412 controls the duration of the switch M2 being turned on or off by detecting the voltage of the first detection signal. The control submodule 412 outputs a sampling control signal representing the duration of the control on or off operation through its electrical connection to the control terminal of the switch M2. For example, the control submodule 412 presets a reference voltage interval that covers the zero-crossing voltage interval corresponding to the zero-crossing phase interval. For example, the setting of the reference voltage interval at least ensures that the upper voltage limit V1 of the reference voltage interval is greater than or equal to the upper voltage limit V2 of the zero-crossing voltage interval.

[0178] In some specific examples, the control submodule first controls the switch to be turned on intermittently according to a preset time interval, and detects the voltage of the first detection signal during the on period. When the voltage of the first detection signal falls into the reference voltage range, the control submodule continuously outputs a sampling control signal to keep the switch M2 in the sampling submodule always on, until zero is detected that the voltage of the first detection signal exceeds the reference voltage range, then controls the switch M2 to be turned off, and controls the switch M2 to be turned on intermittently according to the preset time interval. For example, the control submodule includes a signal generator, a comparator, and a selector. The comparator compares the voltage v of the first detection signal with the upper voltage limit V1 of the reference voltage range. When the voltage v of the first detection signal is greater than or equal to the upper voltage limit V1, the selector, based on the comparison result output by the comparator, connects the control terminal of the signal generator and the switch M2, so that the switch M2 is controlled by the sampling control signal (such as a square wave signal) output by the signal generator and is turned on and off according to a preset on / off cycle. When the voltage v of the first detection signal is less than the upper voltage limit V1, the selector, based on the comparison result output by the comparator, connects the control terminal of the switch to a constant voltage terminal, so that the control terminal of the switch is always on due to the constant voltage signal provided by the constant voltage terminal. Depending on the type of switch in the actual circuit design, the constant voltage terminal can be a voltage ground terminal or the output terminal of a reference voltage source.

[0179] In some specific examples, the control submodule first controls the switch M2 to conduct intermittently according to a preset time interval, and detects the voltage of the first detection signal during the conduction of switch M2. When the voltage of the first detection signal falls into the reference voltage range, at least one of the duty cycle and frequency of the sampling control signal is adjusted to ensure that the voltage of the first detection signal output by the sampling submodule at intervals falls into the zero-crossing voltage range. For example, the control submodule includes an adjustable signal generator and a comparator, wherein the comparator compares the voltage v of the first detection signal with the upper voltage limit V1. When the voltage v of the first detection signal is less than or equal to the upper voltage limit V1, based on the comparison result output by the comparator, the adjustable signal generator outputs a sampling control signal with a first duty cycle to the control terminal of the switch, so that the switch M2 is controlled by the square wave control signal output by the signal generator and is turned on and off according to the period of the square wave control signal. When the voltage v of the first detection signal is greater than the upper voltage limit V1, based on the comparison result output by the comparator, the adjustable signal generator adjusts the duty cycle of the sampling control signal to a second duty cycle and outputs it to the control terminal of the switch; wherein the second duty cycle is less than the first duty cycle.

[0180] In some other examples, the step of generating the sampling control signal includes: when the zero-crossing detection signal is detected to be valid, adjusting the sampling control signal to stop the acquisition operation and starting a sampling interval timer; and when the sampling interval timer reaches a sampling interval threshold, adjusting the sampling control signal to perform the acquisition operation; wherein the first detection signal is generated during the execution of the acquisition operation. This step can be performed by a control submodule in the first detection signal generation module of the zero-crossing detection circuit, the control submodule outputting the sampling control signal to control the switch to open and starting a sampling interval timer; when the sampling interval timer reaches a sampling interval threshold, the control submodule adjusting the sampling control signal to control the switch to turn on. Further details are omitted here.

[0181] In another embodiment, step S110 includes: selecting an AC line through which the AC signal flows to be connected to a first line or a second line to form a corresponding energized circuit; and when the second line is selected, acquiring a second detection signal reflecting the AC signal and using it as the detection signal.

[0182] Therefore, step S110 can be implemented collaboratively by a second detection signal generation module, a selection circuit, a branch control module, and a second sampling circuit, which will not be described in detail here. The selection circuit performs a switching operation between the first line and the second line, that is, it selects whether to connect the AC line flowing through the AC signal to the first line or the second line. The branch control module controls the selection circuit to perform the switching operation. When the selection circuit selects the second line and the second line is turned on, the second detection signal generation module detects the AC signal flowing through the second line and outputs a second detection signal.

[0183] In some examples, the step of selecting whether to connect the AC line through which the AC signal flows to the first line or the second line includes: responding at least immediately to a switching operation from the second line to the first line based on the received branch control signal.

[0184] Taking the use of a selection circuit and a branch control module to perform this step as an example, the selection circuit includes a switching unit M1, which is disposed on the AC power line.

[0185] Here, the switching unit is controlled to disconnect based on the received shunt control signal, so that the switching circuit can be connected to the second line immediately or with a delay, and is controlled to turn on based on the shunt control signal, so that the selection circuit can be switched to connect to the first line. The shunt control signal is output to the switching unit. The switching unit M1 includes a power transistor, the control terminal of which receives the shunt control signal, which is a voltage signal. When the shunt control signal indicates that the switching unit should be turned on, the power transistor is turned on, so that the load and the AC line thereon are connected to the neutral wire via the first line; when the shunt control signal indicates that the switching unit should be turned off, the power transistor is turned off, so that the AC signal flows to the voltage ground in the zero-crossing detection circuit via the second line. Thus, the second signal generation module generates a second detection signal.

[0186] In some examples, the step of responding at least immediately to the switching operation from the second line to the first line based on the received shunt control signal includes: acquiring a second sampled signal reflecting the AC signal flowing through the second line; comparing the voltage of the second sampled signal with the zero-crossing voltage interval corresponding to the zero-crossing phase interval and generating a corresponding comparison result; and outputting the shunt control signal based on the comparison result to switch from the second line to the first line.

[0187] Here, the above steps can be described by the working process of the corresponding selection circuit and shunt control module in the zero-crossing detection circuit, and will not be elaborated here.

[0188] While the selection circuit switches to the first line, a timer is also started. When the timer reaches a timing threshold, the branch control signal is adjusted to switch from the first line to the second line. For example, when the voltage of the detected second sampling signal is greater than the upper limit of the zero-crossing voltage range, a timer is also started. When the timing duration reaches the timing threshold, the branch control signal is adjusted, causing the selection circuit to switch from the first line to the second line immediately or with a delay. The timing threshold is less than the duration of the AC power frequency cycle; for example, the timing threshold is less than half the duration of the power frequency cycle. Figure 4-7 The corresponding descriptions are given as examples, and will not be elaborated further here.

[0189] In some other examples, the step of responding at least immediately to the switching operation from the second line to the first line based on the received shunt control signal includes: generating the shunt control signal based on the zero-crossing detection signal to perform the switching operation from the second line to the first line, and starting a sampling interval timing; and adjusting the shunt control signal when the sampling interval timing reaches a sampling interval threshold to perform the switching operation from the first line to the second line immediately or with a delay. This step can be executed by the shunt control module in the aforementioned zero-crossing detection circuit, and will not be described in detail here.

[0190] After the detection signal is generated, step S120 is executed, which involves detecting the detection signal based on the zero-crossing phase interval and outputting a zero-crossing detection signal according to the detection result. This step can be performed by the zero-crossing detection module in the zero-crossing detection circuit, and will not be described in detail here.

[0191] In some examples, step 120 further includes amplifying the zero-crossing detection signal output by the zero-crossing detection module; wherein the amplification includes amplification based on voltage amplitude and / or amplification based on effective duration. This step can be performed by the zero-crossing detection signal output module in the zero-crossing detection circuit, and will not be described in detail here.

[0192] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this application should still be covered by the claims of this application.

Claims

1. A zero-crossing detection circuit for detecting the zero-crossing phase of an AC signal flowing through an AC power line, characterized in that, include: A detection signal generation circuit is used to periodically generate detection signals that reflect alternating current signals; The detection signal is at least reflected in the AC signal within a preset zero-crossing phase interval; A detection circuit, connected to the detection signal generation circuit, is used to detect the detection signal based on the zero-crossing phase interval and output a zero-crossing detection signal according to the detection result; The detection signal generation circuit includes: The first detection signal generation module is used to generate a first detection signal reflecting the AC signal through an interval acquisition operation within one power frequency cycle of the AC power. The first detection signal is one of the detection signals. The first detection signal generation module acquires the AC signal at a time interval less than one power frequency cycle of the AC power, and outputs the acquired AC signal as the first detection signal after rectification. The first detection signal generation module includes: A sampling submodule including a switch is used to perform a data acquisition operation and output the first detection signal during the on-time of the switch. The control submodule is connected to the control terminal of the switch and is used to output a sampling control signal by detecting the first detection signal or the zero-crossing detection signal to control the switch.

2. The zero-crossing detection circuit according to claim 1, characterized in that, When the voltage of the first detection signal falls into a preset reference voltage range, the control submodule outputs a sampling control signal that is always valid within the reference voltage range, or adjusts at least one of the duty cycle and frequency of the sampling control signal; wherein the reference voltage range covers the zero-crossing voltage range corresponding to the zero-crossing phase range.

3. The zero-crossing detection circuit according to claim 2, characterized in that, When the voltage of the first detection signal is detected to be outside the preset reference voltage range, the control submodule outputs a sampling control signal at a preset interval.

4. The zero-crossing detection circuit according to claim 1, characterized in that, When the zero-crossing detection signal is detected to be valid, the control submodule outputs the sampling control signal to control the switch to open and starts a sampling interval timer; when the sampling interval timer reaches a sampling interval threshold, the control submodule adjusts the sampling control signal to control the switch to turn on.

5. The zero-crossing detection circuit according to any one of claims 1-4, characterized in that, The AC power line is equipped with a switching circuit, and the first detection signal generation module outputs a first detection signal when the switching circuit is open.

6. The zero-crossing detection circuit according to claim 1, characterized in that, It also includes a selection circuit, which is set on the AC power line, for selecting whether to connect the AC power line to the first line or the second line, so as to form a corresponding power-on circuit respectively. The detection signal generation circuit includes a second detection signal generation module, which generates a second detection signal reflecting the AC signal flowing through the second line when the selection circuit selects the second line, and outputs it as the detection signal.

7. The zero-crossing detection circuit according to claim 6, characterized in that, The selection circuit includes a switching unit disposed on the AC line for controlled switching on or off based on a received branch control signal, in order to respond at least immediately to a switching operation from the second line to the first line.

8. The zero-crossing detection circuit according to claim 7, characterized in that, The selection circuit further includes a phase limiting unit, which, when the switching unit is disconnected, delays or immediately responds to the switching operation from the first line to the second line based on the current phase of the AC power.

9. The zero-crossing detection circuit according to claim 8, characterized in that, Also includes: The second sampling circuit is used to sample the AC signal that reflects the current flowing through the second line to generate the second sampling signal; The detection signal generation circuit further includes a branch control module connected to the selection circuit, used to output a branch control signal to the selection circuit by detecting the second sampling signal or the zero-crossing detection signal, so as to control the selection circuit to switch between the first line and the second line.

10. The zero-crossing detection circuit according to claim 9, characterized in that, The branch control module includes: The comparator circuit is used to compare the voltage of the second sampled signal with the zero-crossing voltage interval corresponding to the zero-crossing phase interval, and generate the corresponding comparison result; A control subcircuit, connected to the comparison subcircuit, is used to output the branch control signal based on the comparison result to control the selection circuit to switch from the second line to the first line.

11. The zero-crossing detection circuit according to claim 10, characterized in that, The control sub-circuit includes: a timer for timing based on the received comparison result, and adjusting the branch control signal to control the selection circuit to switch from the first line to the second line when the timing reaches a timing threshold.

12. The zero-crossing detection circuit according to claim 11, characterized in that, The timing threshold is a fixed time threshold, or it is set according to the duration for which the selection circuit selects the first line within at least one switching cycle; wherein the switching cycle is less than the power frequency cycle of the AC power.

13. The zero-crossing detection circuit according to claim 9, characterized in that, The branch control module outputs the branch control signal based on the zero-crossing detection signal to control the switching unit to turn on and start a sampling interval timing; when the sampling interval timing reaches a sampling interval threshold, the branch control module adjusts the branch control signal to control the switching unit to turn off.

14. The zero-crossing detection circuit according to claim 9, characterized in that, The detection signal generation circuit further includes: a first protection module, used to detect the voltage of the second sampling signal, and when the voltage of the second sampling signal is higher than a preset protection voltage threshold, control the selection circuit to switch from the second line to the first line.

15. The zero-crossing detection circuit according to any one of claims 6-14, characterized in that, The AC power line is equipped with a switching circuit, and the second detection signal generation module outputs a second detection signal during the conduction of the switching circuit.

16. The zero-crossing detection circuit according to claim 1, characterized in that, The detection circuit includes a zero-crossing detection module, used to detect the voltage of the received detection signal based on the zero-crossing voltage range corresponding to the zero-crossing phase range, and output the zero-crossing detection signal based on the detection result.

17. The zero-crossing detection circuit according to claim 16, characterized in that, The detection circuit further includes a zero-crossing detection signal output module, used to amplify the zero-crossing detection signal output by the zero-crossing detection module; wherein the amplification process includes amplification based on voltage amplitude and / or amplification based on effective duration.

18. The zero-crossing detection circuit according to claim 17, characterized in that, The zero-crossing detection signal output module converts the zero-crossing detection signal with an effective pulse width provided by the zero-crossing detection module into a zero-crossing detection signal with a preset duration; wherein the duration of the effective pulse width is less than the preset duration.

19. The zero-crossing detection circuit according to claim 1, characterized in that, Also includes: A power supply circuit, used to provide power to at least itself.

20. A chip for detecting the zero-crossing phase of an alternating current signal flowing through an alternating current line, characterized in that, include: At least one first pin is used to acquire an electrical signal that reflects an alternating current signal; The zero-crossing detection circuit as described in claim 1.

21. The chip according to claim 20, characterized in that, The detection signal generation circuit includes: The first detection signal generation module is connected to the first pin and is used to generate a first detection signal reflecting the AC signal through an interval acquisition operation within one power frequency cycle of the AC signal; wherein, the first detection signal of the AC signal is one of the aforementioned detection signals.

22. The chip according to claim 21, characterized in that, The first detection signal generation module includes: A sampling submodule including a switch is used to perform a data acquisition operation and output the first detection signal during the on-time of the switch; wherein the switch is externally located on the chip or integrated into the chip; The control submodule is connected to the control terminal of the switch and is used to output a sampling control signal by detecting the first detection signal or the zero-crossing detection signal to control the switch.

23. The chip according to claim 22, characterized in that, When the voltage of the first detection signal falls into a preset reference voltage range, the control submodule outputs a sampling control signal that is always valid within the reference voltage range, or adjusts at least one of the duty cycle and frequency of the sampling control signal; wherein the reference voltage range covers the zero-crossing voltage range corresponding to the zero-crossing phase range.

24. The chip according to claim 23, characterized in that, When the voltage of the first detection signal is detected to be outside the preset reference voltage range, the control submodule outputs a sampling control signal at a preset interval.

25. The chip according to claim 22, characterized in that, When the zero-crossing detection signal is detected to be valid, the control submodule outputs the sampling control signal to control the switch to open and starts a sampling interval timer; when the sampling interval timer reaches a sampling interval threshold, the control submodule adjusts the sampling control signal to control the switch to turn on.

26. The chip according to any one of claims 21-25, characterized in that, The AC power line is equipped with a switching circuit, and the first detection signal generation module outputs a first detection signal when the switching circuit is open.

27. The chip according to claim 20, characterized in that, It also has a second pin for connecting to an AC power line; the second pin is used to connect to the integrated selection circuit, or to connect to the AC power line through the selection circuit; wherein, the selection circuit is used to select whether to connect the AC power line to the first line or the second line, so as to form a corresponding power-on circuit respectively; The detection signal generation circuit includes a second detection signal generation module, which generates a second detection signal reflecting the AC signal flowing through the second line when the selection circuit selects the second line, and outputs it as the detection signal.

28. The chip according to claim 27, characterized in that, The selection circuit includes a switching unit disposed on the AC line for controlled switching on or off based on a received branch control signal, in order to respond at least immediately to a switching operation from the second line to the first line.

29. The chip according to claim 28, characterized in that, The selection circuit further includes a phase limiting unit, which, when the switching unit is disconnected, delays or immediately responds to the switching operation from the first line to the second line based on the current phase of the AC power.

30. The chip according to claim 29, characterized in that, Also includes: The second sampling circuit is used to sample the AC signal that reflects the current flowing through the second line to generate the second sampling signal; The detection signal generation circuit further includes a branch control module connected to the selection circuit, used to output a branch control signal to the selection circuit by detecting the second sampling signal or the zero-crossing detection signal, so as to control the selection circuit to switch between the first line and the second line.

31. The chip according to claim 30, characterized in that, The branch control module includes: The comparator circuit is used to compare the voltage of the second sampled signal with the zero-crossing voltage interval corresponding to the zero-crossing phase interval, and generate the corresponding comparison result; A control subcircuit, connected to the comparison subcircuit, is used to output the branch control signal based on the comparison result to control the selection circuit to switch from the second line to the first line.

32. The chip according to claim 31, characterized in that, The control sub-circuit includes: a timer for timing based on the received comparison result, and adjusting the branch control signal to control the selection circuit to switch from the first line to the second line when the timing reaches a timing threshold.

33. The chip according to claim 32, characterized in that, The timing threshold is a fixed time threshold, or it is set according to the duration for which the selection circuit selects the first line within at least one switching cycle; wherein the switching cycle is less than the power frequency cycle of the AC power.

34. The chip according to claim 30, characterized in that, The branch control module outputs the branch control signal based on the zero-crossing detection signal to control the switching unit to turn on and start a sampling interval timing; when the sampling interval timing reaches a sampling interval threshold, the branch control module adjusts the branch control signal to control the switching unit to turn off.

35. The chip according to claim 27, characterized in that, The detection signal generation circuit further includes: a first protection module, used to detect the electrical signal voltage reflecting the AC signal flowing through the second line, and when the voltage is higher than a preset protection voltage threshold, control the selection circuit to switch from the second line to the first line.

36. The chip according to any one of claims 27-35, characterized in that, The AC power line is equipped with a switching circuit, and the second detection signal generation module outputs a second detection signal during the conduction of the switching circuit.

37. The chip according to claim 20, characterized in that, The detection circuit includes a zero-crossing detection module, used to detect the voltage of the received detection signal based on the zero-crossing voltage range corresponding to the zero-crossing phase range, and output the zero-crossing detection signal based on the detection result.

38. The chip according to claim 37, characterized in that, The detection circuit further includes: a zero-crossing detection signal output module, used to amplify the zero-crossing detection signal output by the zero-crossing detection module; wherein the amplification process includes amplification based on voltage amplitude and / or amplification based on effective duration.

39. The chip according to claim 38, characterized in that, The zero-crossing detection signal output module converts the zero-crossing detection signal with an effective pulse width provided by the zero-crossing detection module into a zero-crossing detection signal with a preset duration; wherein the duration of the effective pulse width is less than the preset duration.

40. The chip according to claim 20, characterized in that, It also integrates a power supply circuit; wherein the power supply circuit is used to provide power to at least the chip.

41. A smart switch for connecting to an AC power line containing a load, characterized in that, The smart switch includes: A switching circuit is connected to the AC power line and is controlled to be turned on or off; The zero-crossing detection circuit as described in any one of claims 1-19 is used to output a zero-crossing detection signal; A control circuit, connected to the zero-crossing detection circuit, is used to control the switching circuit to be turned on or off based on the zero-crossing detection signal and the received control information.

42. The intelligent switch according to claim 41, characterized in that, The control circuit includes: An interaction unit is used to acquire control information; The processing unit, connected to the interaction unit, is used to control at least the switching circuit to be turned on or off based on the control information.

43. The intelligent switch according to claim 42, characterized in that, After receiving a control message, the processing unit controls the switching circuit to turn on or off during the valid period of the zero-crossing detection signal; or, the processing unit generates a response timer based on the zero-crossing detection signal, and controls the switching circuit to turn on or off when the response timer expires and the control message is received.

44. The intelligent switch according to claim 43, characterized in that, The processing unit determines the response timing based on the zero-crossing detection signals acquired multiple times, and controls the switching circuit to be turned on or off based on the response timing timeout, the received control information, and the zero-crossing detection signals.

45. The intelligent switch according to claim 41, characterized in that, It also includes a rectifier circuit, used to rectify the connected AC signal and output a rectified signal during the off-state and on-state of the switching circuit, respectively.

46. ​​The intelligent switch according to claim 45, characterized in that, The rectifier circuit includes at least one of the following: The first rectifier unit is connected to the AC power line connected to the input terminal of the switching circuit, and is used to rectify the AC power flowing to the switching circuit and output a first rectified signal; wherein, the first rectified signal is a rectified signal provided by the rectifier circuit. The second rectifier unit is connected to the AC power line connected to the output terminal of the switching circuit, and is used to rectify the AC power and output a second rectified signal; wherein the second rectified signal is another rectified signal provided by the rectifier circuit.

47. The intelligent switch according to claim 46, characterized in that, The rectifier circuit includes a first rectifier unit and a second rectifier unit; wherein the first rectifier unit provides a first rectified electrical signal when the switching circuit is off, and the second rectifier unit provides a second rectified electrical signal when the switching circuit is on.

48. The intelligent switch according to claim 47, characterized in that, Both the first rectifier unit and the second rectifier unit include a rectifier bridge and a filter capacitor; wherein, the forward voltage of the rectifier bridge in the first rectifier unit is higher than the forward voltage of the rectifier bridge in the second rectifier unit.

49. The intelligent switch according to any one of claims 45-48, characterized in that, Also includes: A power supply circuit, connected to the rectifier circuit, is used to provide power to a power supply via the rectified electrical signal; wherein the power supply is used to provide power to at least one of the control circuit, the switching circuit, and the power supply circuit itself.

50. The intelligent switch according to claim 41, characterized in that, The switching circuit includes a relay.

51. A zero-crossing detection method, characterized in that, include: It generates detection signals that reflect alternating current signals at intervals; The detection signal is at least reflected in the AC signal within a preset zero-crossing phase interval; The detection signal is detected based on the zero-crossing phase interval, and a zero-crossing detection signal is output according to the detection result; The step of intermittently generating a detection signal reflecting an AC signal includes: generating a first detection signal reflecting an AC signal by intermittent acquisition within one power frequency cycle of the AC signal, wherein the first detection signal is one of the detection signals, wherein the AC signal is acquired at time intervals less than one power frequency cycle of the AC signal, and the acquired AC signal is rectified and output as the first detection signal. The step of generating a first detection signal reflecting the AC signal through interval acquisition operations within one power frequency cycle of the AC power includes: A sampling control signal is used to perform a data acquisition operation and generate a first detection signal that reflects the AC signal. The sampling control signal is generated by detecting the first detection signal or the zero-crossing detection signal.

52. The zero-crossing detection method according to claim 51, characterized in that, When the voltage of the first detection signal falls within a preset reference voltage range, the step of generating the sampling control signal includes any of the following steps: The sampling control signal shall remain valid throughout the reference voltage range; or Adjust at least one of the duty cycle and frequency of the sampling control signal; The reference voltage range covers the zero-crossing voltage range corresponding to the zero-crossing phase range.

53. The zero-crossing detection method according to claim 52, characterized in that, When the voltage of the first detection signal is detected to be outside the preset reference voltage range, the step of generating the sampling control signal includes the step of outputting the sampling control signal at a preset interval.

54. The zero-crossing detection method according to claim 51, characterized in that, The step of generating the sampling control signal includes: when the zero-crossing detection signal is detected to be valid, adjusting the sampling control signal to stop the acquisition operation and starting a sampling interval timer; and when the sampling interval timer reaches a sampling interval threshold, adjusting the sampling control signal to perform the acquisition operation; wherein the first detection signal is generated during the execution of the acquisition operation.

55. The zero-crossing detection method according to claim 51, characterized in that, The step of generating detection signals that reflect alternating current signals at intervals includes: The AC line through which the AC signal flows is selected to be connected to the first line or the second line to form a corresponding energized circuit. When the second line is selected, a second detection signal reflecting the AC signal is acquired and used as the detection signal.

56. The zero-crossing detection method according to claim 55, characterized in that, The step of selecting whether to connect the AC line through which the AC signal flows to the first line or the second line includes: responding at least immediately to a switching operation from the second line to the first line based on the received branch control signal.

57. The zero-crossing detection method according to claim 56, characterized in that, The steps for responding at least immediately to the switching operation from the second line to the first line based on the received branch control signal include: Acquire a second sampling signal to reflect the AC signal flowing through the second line; The voltage of the second sampled signal is compared with the zero-crossing voltage interval corresponding to the zero-crossing phase interval, and a corresponding comparison result is generated; Based on the comparison result, the branch control signal is output to switch from the second line to the first line.

58. The zero-crossing detection method according to claim 57, characterized in that, Also includes: The steps include timing based on the received comparison results, and adjusting the branch control signal to switch from the first line to the second line when the timing reaches a timing threshold.

59. The zero-crossing detection method according to claim 58, characterized in that, The step of adjusting the branch control signal to switch from the first line to the second line when the timing reaches a timing threshold includes: when the timing reaches a timing threshold, delaying or immediately responding to the switching operation from the first line to the second line based on the branch control signal and the phase of the current AC power.

60. The zero-crossing detection method according to claim 56, characterized in that, The step of responding at least immediately to the switching operation from the second line to the first line based on the received split control signal includes: generating the split control signal based on the zero-crossing detection signal to perform the switching operation from the second line to the first line, and starting a sampling interval timing; and when the sampling interval timing reaches a sampling interval threshold, adjusting the split control signal to perform the switching operation from the first line to the second line immediately or with a delay.

61. The zero-crossing detection method according to claim 51, characterized in that, Also includes: The zero-crossing detection signal is amplified; wherein the amplification process includes amplification based on voltage amplitude and / or amplification based on effective duration.

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