Single firewire switch power taking circuit, control circuit and intelligent switch

Abstract

The application discloses a single-firewire switch power taking circuit, a control circuit and an intelligent switch. The intelligent switch at least comprises a first firewire incoming line end, a firewire outgoing line end, a first controllable switch and a control circuit. The first controllable switch is connected in series between the first firewire incoming line end and a reference ground. The single-firewire switch power taking circuit comprises: an off-state power taking circuit, which comprises a first diode, a first switch tube, a second switch tube, a first inductor, a second diode and a second capacitor connected in series between the first firewire incoming line end and the reference ground in sequence, and is used for working when the first controllable switch is turned off, so as to supply power for the control circuit; and an on-state power taking circuit, which comprises the first controllable switch, the second switch tube, the first inductor, the second diode and the second capacitor connected in series between the first firewire incoming line end and the reference ground in sequence, and is used for working when the first controllable switch is turned on, so as to supply power for the control circuit. The circuit structure is simplified, the power taking efficiency is high, and the circuit loss is low.

Description

Technical Field

[0001] This invention application relates to the fields of smart home, lighting control and power supply technology, and in particular to a single-wire switch power supply circuit, control circuit and smart switch. Background Technology

[0002] The schematic diagram of an existing single-wire smart switch is as follows: Figure 1 As shown, the main control switch Q1 is typically a silicon controlled rectifier (SCR), connected in series between the live wire and the load (such as an LED light), with no neutral wire connected. This is to power the control circuit within the smart switch (i.e.,...) Figure 1 The BP2535C controller in this system (which can power MCUs, wireless communication modules, etc.) needs to address two major challenges: "power supply in the off state" and "power supply in the on state." Power supply in the off state refers to the power supply circuit needing to draw a small current to power the control circuit when the load is off, but this current may cause LEDs to flicker or energy-saving lamps to trigger falsely. Power supply in the on state refers to the power supply circuit needing to provide a stable power supply while ensuring the load functions normally, and simultaneously avoiding interference with the normal conduction of the thyristor.

[0003] Existing solutions often have the following shortcomings:

[0004] First, the circuitry is complex. Some solutions require multiple isolated power supplies or dedicated power chips, which are costly, bulky, and difficult to integrate into standard wall switch sizes.

[0005] Second, the reliability of thyristor drives is low. Traditional optocoupler or pulse transformer drive circuits have many components and strict requirements on the trigger pulse width, making them prone to trigger failure when the load changes, resulting in flickering lights or failure to light up.

[0006] Third, zero-crossing detection relies on optocouplers. This increases cost and PCB area, and limits response speed, making precise zero-crossing control impossible.

[0007] Fourth, multi-switch linkage is difficult. In two- or three-position switch scenarios, the lack of a unified power supply and linkage control strategy can easily lead to power supply conflicts or insufficient power supply.

[0008] Fifth, the switching surge is large. The lack of effective zero-crossing control results in a large inrush current during turn-on and turn-off, affecting the lifespan of devices and loads. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to provide a single-wire switch power supply circuit, control circuit and intelligent switch, which at least partially solves one of the technical problems existing in the prior art.

[0010] As a first aspect of the present invention, the embodiment of the single-wire switch power supply circuit is as follows: A single-wire power supply circuit is provided for use in a smart switch. The smart switch includes at least a first live wire input terminal, a live wire output terminal, a first controllable switch, and a control circuit. The first controllable switch is connected in series between the first live wire input terminal and a reference ground, and is controlled by the control circuit to perform on / off actions. The single-wire power supply circuit includes: The off-state power supply circuit includes a first diode, a first switching transistor, a second switching transistor, a first inductor, a second diode, and a second capacitor connected in series between the first live wire input terminal and the reference ground. The off-state power supply circuit is used to operate when the first controllable switch is turned off. The first switching transistor and the second switching transistor are controlled by the control circuit to form a stable output voltage across the second capacitor, thereby supplying power to the control circuit. The on-state power supply circuit includes a first controllable switch, a second switching transistor, a first inductor, a second diode, and a second capacitor connected in series between the first live wire input terminal and the reference ground. The on-state power supply circuit is used to operate when the first controllable switch is turned on. The first controllable switch and the second switching transistor are controlled by the control circuit to form a stable output voltage across the second capacitor, thereby supplying power to the control circuit.

[0011] Optionally, when the power-off circuit is working, the second switch remains in the on state, and the first switch is controlled by the control circuit to perform high-frequency switching. When the first switch is turned on, the current at the first live wire input terminal flows through the first diode, the first switch, the second switch, and the first inductor to the live wire output terminal, and the first inductor stores energy. When the first switch is turned off, the first inductor releases energy, and the current flows through the second diode, the second capacitor, and the second switch back to the first inductor, while the second capacitor is charged.

[0012] Optionally, when the power supply circuit is in operation, the first controllable switch is turned on, the first switching transistor is always turned off, and the second switching transistor is controlled by the control circuit to turn on or off. When the output voltage is higher than the second threshold, the second switch is turned on, and the current flows in the current path formed by the first live wire input terminal, the first controllable switch, the second switch, the first inductor and the live wire output terminal; When the voltage across the second capacitor is lower than the first threshold, the second switch is turned off, and the current from the live wire output terminal flows through the second diode, the second capacitor, and the first controllable switch to the first live wire input terminal to charge the second capacitor.

[0013] As a second aspect of the present invention, the technical solution of the provided control circuit embodiment is as follows: A control circuit, applicable to the single-wire switch power supply circuit according to any one of the first aspects above, wherein the control circuit comprises: The first driving terminal is used to connect to the control terminal of the first switching transistor; The second driving terminal is used to connect to the control terminal of the second switching transistor; The third driving end is used to connect to the control end of the first controllable switch; A communication interface or panel button is used to receive instructions to control the first controllable switch to perform an on or off action; Memory, used to store programs; A digital controller is configured to respond to the instructions to run the program in order to generate a first control signal, a second control signal, and a third control signal; The first controllable switch driving module generates a third driving signal at the third driving terminal according to the third control signal to drive the first controllable switch; The drive output module generates a first drive signal at the first drive terminal based on the first control signal to drive the first switching transistor, and generates a second drive signal at the second drive terminal based on the second control signal to drive the first switching transistor.

[0014] Optionally, the drive output module includes a shutdown controller module and an on-state controller module; the shutdown controller module generates the first drive signal, and the on-state controller module generates the second drive signal. The first control signal is used to control the power supply of the off-state controller module, and the second control signal is used to control the power supply of the on-state controller module, so that the off-state controller module and the on-state controller module do not operate simultaneously: When the single live wire switch power supply circuit is in the off-state power supply mode, only the off-state controller module is powered on. The first drive signal generated by the off-state controller module controls the first switch to perform high-frequency switching, and the second drive signal generated by the on-state controller module controls the second switch to remain in the on state. When the single-wire switch power supply circuit is in the on-state power supply mode, only the on-state controller module is powered on. The first drive signal generated by the off-state controller module controls the first switch to remain in the off state, and the second drive signal generated by the on-state controller module controls the second switch to be turned on or off.

[0015] Optionally, the control circuit further includes an output voltage feedback terminal and an over / under voltage detection module. The over / under voltage detection module is connected to the output voltage through the output voltage feedback terminal and detects whether the output voltage is within a set threshold when the single-wire power supply circuit is in the on-state power supply mode, thereby obtaining an over / under voltage signal. The drive output module controls the second switch to be turned on or off according to the over / under voltage signal, so that the voltage across the second capacitor is within the set threshold.

[0016] As a third aspect of the present invention, the technical solution of the provided intelligent switch embodiment is as follows: A smart switch includes at least a first live wire inlet terminal, a live wire outlet terminal, a first controllable switch, and a control circuit. The first controllable switch is connected in series between the first live wire inlet terminal and a reference ground and is controlled by the control circuit to perform on and off actions. The smart switch further includes the single live wire switch power supply circuit described in any of the first aspects and the control circuit described in any of the second aspects.

[0017] Optionally, the first controllable switch is a bidirectional thyristor.

[0018] Optionally, the bidirectional thyristor is driven by a first controllable switch driving module, which includes a two-terminal network formed by a first resistor and a third capacitor connected in series. The two-terminal network is connected between the control electrode of the bidirectional thyristor and the third driving terminal of the control circuit.

[0019] Optionally, the smart switch further includes a first input voltage sampling circuit, and the control circuit further includes an input voltage detection terminal, a bias module, and an input voltage detection module. The first input voltage sampling circuit includes a fourth capacitor, a fifth capacitor, and a second resistor. One end of the fourth capacitor is connected to the first live wire input terminal, and the other end of the fourth capacitor is simultaneously connected to one end of the fifth capacitor, one end of the second resistor, and the input voltage detection terminal. The other ends of the fifth capacitor and the other ends of the second resistor are connected to reference ground. The bias module is used to raise the voltage information of the input voltage detection terminal to a first voltage information that meets the internal level requirements of the control circuit. The input voltage detection module is used to identify the zero-crossing moment of the voltage connected to the first live wire input terminal based on the first voltage information and obtain the zero-crossing signal. The digital controller generates a third control signal based on the zero-crossing signal to drive the bidirectional thyristor to conduct at the zero-crossing moment of the voltage at the first live wire input terminal, or removes the third control signal based on the zero-crossing signal to allow the bidirectional thyristor to turn off naturally at the zero-crossing moment of the current at the first live wire input terminal.

[0020] Optionally, the smart switch further includes N controllable switches and N corresponding live wire input terminals, where N is a natural number greater than or equal to 1. The N controllable switches are connected in series between the corresponding live wire input terminal and the reference ground, and are used to independently control the on / off of N loads. The N controllable switches are controlled by the drive signal output by the corresponding drive terminal of the control circuit to perform conduction and shutdown actions. The control of the N controllable switches and the first controllable switch share the power supply circuit in the off state. In the on state, the power supply circuit is shared by the other components after the first controllable switch is replaced with the corresponding controllable switch among the N controllable switches.

[0021] Compared with the prior art, the present invention has the following beneficial effects: First, the circuit structure is simplified. By reusing core components such as the second switching transistor and the first inductor, the power supply circuits for both on and off states are highly integrated, reducing the number of components, lowering costs, and facilitating integration into standard wall switch sizes.

[0022] Secondly, it is highly adaptable to multi-switch scenarios. It supports dual-switch and triple-switch expansion, and multiple thyristors can be controlled independently, avoiding power supply conflicts and load flickering issues in multi-switch systems. Attached Figure Description

[0023] Figure 1 The schematic diagram of an existing single-wire smart switch; Figure 2 This is a schematic diagram of a single-wire intelligent switch according to the first embodiment of the present invention; Figure 3 for Figure 2 Internal functional module block diagram of the control circuit; Figure 4 for Figure 2 Waveform diagram showing the phase relationship between the input voltage signal of the circuit input voltage detection terminal Vin_sense and the voltage signal of the first live wire input terminal Lin1; Figure 5 for Figure 3 Flowchart of the control method for the control circuit under the off-state power-on condition; Figure 6 for Figure 3 Flowchart of the control method for the control circuit under the on-state power supply condition; Figure 7 for Figure 2 Timing diagram for the control of the thyristor's zero-crossing turn-on and zero-crossing turn-off in the circuit; Figure 8 This is a schematic diagram of a single-wire intelligent switch according to a second embodiment of the present invention; Figure 9 This is a schematic diagram of a single-wire intelligent switch according to the third embodiment of the present invention. Detailed Implementation

[0024] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0025] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0026] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be used interchangeably where appropriate for the purposes of describing embodiments of this application herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0027] It should be understood that in the specification, claims, and drawings, when a step is described as continuing into another step, the step may directly continue into that other step or be continued into that other step through a third step; when an element / unit is described as being "connected" to another element / unit, the element / unit may be "directly connected" to that other element / unit or be "connected" to that other element / unit through a third element / unit.

[0028] Furthermore, the accompanying drawings are merely illustrative of this disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions thereof will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0029] First Embodiment The smart switch in this embodiment has only one master control switch. Figure 2 Please refer to the schematic diagram of the single-wire intelligent switch according to the first embodiment of the present invention. Figure 2It includes at least a first live wire input terminal Lin1, a live wire output terminal Lout, a first controllable switch Q3 (the main control switch) and a control circuit. The first controllable switch Q3 is connected in series between the first live wire input terminal Lin1 and the reference ground, and is controlled by the control circuit to perform conduction and shutdown actions.

[0030] As an example, please continue to see Figure 2 The single-wire power supply circuit includes: The off-state power supply circuit includes a first diode D1, a first switch Q1, a second switch Q2, a first inductor L1, a second diode D2, and a second capacitor C2 connected in series between the first live wire input terminal Lin1 and the reference ground. The off-state power supply circuit is used to operate when the first controllable switch Q3 is turned off. The first switch Q1 and the second switch Q2 are controlled by the control circuit to form a stable output voltage Vo across the second capacitor C2, thereby supplying power to the control circuit. The on-state power supply circuit includes a first controllable switch Q3, a second switching transistor Q2, a first inductor L1, a second diode D2, and a second capacitor C2 connected in series between the first live wire input terminal Lin1 and the reference ground. The on-state power supply circuit is used to operate when the first controllable switch Q3 is turned on. The first controllable switch Q3 and the second switching transistor Q2 are controlled by the control circuit to form a stable output voltage Vo across the second capacitor C2, thereby supplying power to the control circuit.

[0031] As an example, when the power-on circuit is in operation in the off state, the second switch Q2 remains in the on state, and the first switch Q1 is controlled by the control circuit to perform high-frequency switching. When the first switch Q1 is on, the current at the input terminal of the first live wire flows through the first diode D1, the first switch Q1, the second switch Q2, and the first inductor L1 to the output terminal of the first live wire, where the first inductor L1 stores energy. When the first switch Q1 is off, the first inductor L1 releases its energy, and the current flows through the second diode D2, the second capacitor C2, and the second switch Q2 back to the first inductor L1, where the second capacitor C2 is charged.

[0032] As an example, when the power-on circuit is working, the first controllable switch Q3 is turned on, the first switch Q1 remains off, and the second switch Q2 is controlled by the control circuit to turn on or off. When the output voltage is higher than the second threshold, the second switch Q2 turns on, and the current flows in the current path formed by the first live wire input terminal, the first controllable switch Q3, the second switch Q2, the first inductor L1, and the first live wire output terminal. Since the circuit operates at a low frequency of 50Hz, the first inductor L1 is regarded as a wire and not as an energy storage element. When designing the inductor L1, it will be designed according to the maximum current passing through the inductor in the open state to avoid saturation of the inductor L1. When the voltage across the second capacitor C2 is lower than the first threshold, the second switch Q2 turns off, and the current at the first live wire output terminal flows through the second diode D2, the second capacitor C2, and the first controllable switch Q3 to the first live wire input terminal to charge the second capacitor C2. Since the second switching transistor Q2 switches only according to the output voltage threshold, it does not require high-frequency PWM control, thus avoiding high-frequency switching losses and resulting in low overall circuit losses.

[0033] In practical implementation, the load (such as LED lights), Figure 2 (Not shown) is connected between the live wire output terminal Lout and the neutral wire. Capacitor C1 is the bus capacitor, connected between the first live wire input terminal Lin1 and the input capacitor ground (i.e., the connection point between the first inductor L1 and the anode of the second diode D2).

[0034] The power-off and power-on circuits in this embodiment reduce the number of components and lower product costs by reusing core components such as the second switch Q2 and the first inductor L1, making it easier to integrate the smart switch into the standard wall switch size.

[0035] As an example, a control circuit is provided, the internal functional module block diagram of which is as follows: Figure 3 As shown, it includes: a first drive terminal Vg1, used to connect to the control terminal of the first switch Q1; a second drive terminal Vg2, used to connect to the control terminal of the second switch Q2; a third drive terminal Drv, used to connect to the control terminal of the first controllable switch Q3; a communication interface or panel buttons, used to receive instructions to control the first controllable switch Q3 to perform on or off actions; a memory, used to store programs; a digital controller, used to respond to instructions to run programs, thereby generating a first control signal, a second control signal, and a third control signal; a first controllable switch drive module, which generates a third drive signal at the third drive terminal based on the third control signal to drive the first controllable switch Q3; and a drive output module, which generates a first drive signal at the first drive terminal based on the first control signal to drive the first switch Q1, and generates a second drive signal at the second drive terminal based on the second control signal to drive the second switch Q2.

[0036] As an example, please continue to see Figure 3The drive output module includes a power-off controller module and a power-on controller module. The power-off controller module generates a first drive signal, and the power-on controller module generates a second drive signal. The first control signal is used to control the power supply Vcc1 of the power-off controller module, and the second control signal is used to control the power supply Vcc2 of the power-on controller module, so that the power-off controller module and the power-on controller module do not operate simultaneously to reduce power consumption. When the single-wire switch power supply circuit is in the power-off mode, only the power-off controller module is powered on. The first drive signal generated by the power-off controller module controls the first switch Q1 to perform high-frequency switching, and the second drive signal generated by the power-on controller module controls the second switch Q2 to remain in the on state. When the single-wire switch power supply circuit is in the power-on mode, only the power-on controller module is powered on. The first drive signal generated by the power-off controller module controls the first switch Q1 to remain in the off state, and the second drive signal generated by the power-on controller module controls the second switch Q2 to be turned on or off.

[0037] As an example, please continue to see Figure 3 The control circuit also includes an output voltage feedback terminal Vo_sense and an over / under voltage detection module. The over / under voltage detection module is connected to the output voltage Vo through the output voltage feedback terminal Vo_sense. It detects whether the output voltage Vo is within the set threshold when the single-wire switch power supply circuit is in the on state power supply mode, obtains the over / under voltage signal, and drives the output module to control the second switch Q2 to turn on or off according to the over / under voltage signal, so that the voltage across the second capacitor C2 is within the set threshold.

[0038] As an example, please return to Figure 2 The first controllable switch Q3 is a bidirectional thyristor.

[0039] As an example, please continue to see Figure 2 The bidirectional thyristor is driven by a first controllable switch driver module, which includes a two-terminal network formed by a first resistor R1 and a third capacitor C3 connected in series. The positions of these two components can be interchanged. The two sub-networks are connected between the control electrode of the bidirectional thyristor and the third driving terminal of the control circuit. This direct RC drive method eliminates the need for optocouplers or pulse transformers compared to existing technologies, resulting in a simpler, more reliable circuit with lower pulse width requirements.

[0040] As an example, please continue to see Figure 2 and Figure 3 The smart switch also includes a first input voltage sampling circuit, and the control circuit includes an input voltage detection terminal Vin_sense, a bias module, and an input voltage detection module. As an example, please continue to see Figure 2The first input voltage sampling circuit includes a fourth capacitor C4, a fifth capacitor C5, and a second resistor R2. One end of the fourth capacitor C4 is connected to the first live wire input terminal Lin1, and the other end of the fourth capacitor C4 is simultaneously connected to one end of the fifth capacitor C5, one end of the second resistor R2, and the input voltage detection terminal Vin_sense. The other end of the fifth capacitor C5 and the other end of the second resistor R2 are connected to reference ground. Due to the differentiating characteristics of the pure capacitive voltage divider network, there is an approximately 90° phase difference between the sampled voltage signal (i.e., the first voltage signal at the input voltage detection terminal Vin_sense) and the voltage signal at the first live wire input terminal Lin1. Figure 4 As shown, S001 is the input AC voltage and S002 is the first voltage signal. Therefore, the zero-crossing point of the voltage signal at the input voltage detection terminal Vin_sense corresponds to the peak point of the voltage signal at the first live wire input terminal Lin1, and the peak point of the voltage signal at the input voltage detection terminal Vin_sense corresponds to the zero-crossing point of the voltage signal at the first live wire input terminal Lin1. By using capacitive voltage division to sample the voltage signal at the first live wire input terminal Lin1, an accurate zero-crossing signal can be provided to the control circuit without optocouplers or transformers, reducing cost and PCB area compared to existing technologies.

[0041] As an example, please continue to see Figure 3 The bias module is used to raise the voltage information of the input voltage detection terminal Vin_sense (e.g., raise it by 2.5V) to the first voltage information that meets the internal level requirements of the control circuit. The input voltage detection module is used to identify the zero-crossing moment of the voltage connected to the first live wire input terminal based on the first voltage information and obtain the zero-crossing signal. The digital controller generates a third control signal based on the zero-crossing signal to drive the bidirectional thyristor to conduct at the zero-crossing moment of the voltage at the first live wire input terminal, or removes the third control signal based on the zero-crossing signal to make the bidirectional thyristor turn off naturally at the zero-crossing moment of the current at the first live wire input terminal.

[0042] As an example, the digital controller uses a software algorithm to calculate the zero-crossing moment of the voltage at the first live wire input. When an external light-on signal is received, it does not immediately trigger the bidirectional thyristor to turn on, but delays until the next zero-crossing moment of the voltage at the first live wire input to trigger the bidirectional thyristor to turn on. Similarly, when an external light-off signal is received, it does not immediately remove the drive signal of the bidirectional thyristor, but delays until the next zero-crossing moment of the voltage at the first live wire input to remove the drive signal of the bidirectional thyristor, allowing the bidirectional thyristor to turn off naturally. The purpose of this is to effectively reduce the impact of the pulse current generated during the switching process on the bidirectional thyristor and the load, effectively extending the service life of the device.

[0043] As an example: the input voltage detection module can detect the zero-crossing moment of the voltage signal at the input voltage detection terminal Vin_sense, and the digital controller can obtain the actual zero-crossing moment of the voltage at the first live wire input terminal by delaying the zero-crossing moment by 1 / 4 cycle (5ms for 50Hz and approximately 4.17ms for 60Hz); or the input voltage detection module can detect the peak point of the voltage signal at the input voltage detection terminal Vin_sense, and the digital controller can directly use the moment when the peak point appears as the zero-crossing moment of the voltage at the first live wire input terminal.

[0044] The aforementioned first input voltage sampling circuit utilizes the inherent phase-shifting characteristics of a low-cost capacitor voltage divider sampling network, combined with the built-in software compensation algorithm of the digital controller, to accurately obtain the zero-crossing moment of the voltage at the first live wire input terminal, thereby realizing the zero-crossing turn-on and zero-crossing turn-off of the thyristor, significantly reducing switching impact, and extending the lifespan of the thyristor and the load.

[0045] Figure 5 for Figure 3 The flowchart of the control method for the control circuit under the off-state power-on condition is as follows: In step S101, after the digital controller receives the light-off command through the communication interface or panel buttons, it first removes the drive signal of the bidirectional thyristor through the third drive terminal Drv, thus turning off the bidirectional thyristor. At this time, the digital controller provides power Vcc1 to the off-state controller module by closing the corresponding switch, and disconnects the power Vcc2 of the on-state controller module by opening the corresponding switch. The smart switch enters the off-state power-on mode, and outputs a high level through the second drive terminal Vg2 to keep the second switch Q2 continuously conducting.

[0046] Step S102: Monitor the output voltage Vo in real time through the output voltage feedback terminal Vo_sense.

[0047] In step S103, when the output voltage Vo is lower than the set off-state first threshold (low threshold), the off-state controller outputs a high-frequency PWM pulse through the first drive terminal Vg1 to turn on the first switch Q1. The current path is: first live wire input terminal Lin → first diode D1 → first switch Q1 → second switch Q2 → first inductor L1 → live wire output terminal Lout. At this time, the first inductor L1 stores energy.

[0048] In step S104, when the output voltage Vo rises to the second threshold (high threshold) of the off state, the off-state controller turns off the first switch Q1, and the first inductor L1 charges the second capacitor C2 through the second diode D2. Specifically, the freewheeling current generated by the first inductor L1 flows through the second diode D2, the second capacitor C2, and the second switch Q2 in sequence back to the first inductor L1, and the second capacitor C2 supplies power to the control circuit.

[0049] Repeat steps S102-S104 above to stabilize the output voltage Vo within the set range.

[0050] Figure 6 for Figure 3 The flowchart of the control method for the control circuit under the on-state power-off condition is as follows: In step S201, after the digital controller receives the light-on command, it first accurately obtains the zero-crossing moment of the voltage at the first live wire input terminal through the input voltage detection module and the digital controller. It waits for the next zero-crossing moment before outputting the third drive signal through the third drive terminal Drv to turn on the bidirectional thyristor. The digital controller provides power Vcc2 to the on-state controller module by closing the corresponding switch transistor and disconnects the power Vcc1 of the on-state controller module by opening the corresponding switch transistor. The smart switch enters the on-state power-on mode and keeps the first switch transistor Q1 off through the first drive terminal Vg1.

[0051] Step S202: Monitor the output voltage Vo in real time through the output voltage feedback terminal Vo_sense.

[0052] In step S203, when the output voltage Vo is lower than the set first threshold (low threshold) of the on-state, the on-state controller outputs a low level through the second drive terminal Vg2 to turn off the second switch Q2. The current charges the second capacitor C2 through the second diode D2. Specifically, the current flows from the first live wire input terminal Lin1 to the first controllable switch Q3, the second switch Q2, the first inductor L1, and the live wire output terminal Lout, and the output voltage Vo rises.

[0053] In step S204, when the output voltage Vo rises to the second threshold (high threshold) of the open state, the open controller outputs a high level through the second drive terminal Vg2 to turn on the second switch Q2. The current flows in the low impedance path formed by the first live wire input terminal Lin1, the first controllable switch Q3, the second switch Q2, the first inductor L1 and the live wire output terminal Lout, stopping the charging of the second capacitor C2, and the second capacitor C2 supplies power to the control circuit.

[0054] Repeat steps S202-S204 above to stabilize the output voltage Vo between the low threshold and the high threshold.

[0055] Figure 7 for Figure 2 For the control timing diagram of the thyristor's zero-crossing turn-on and zero-crossing turn-off, please refer to [link / reference]. Figure 7S001 is the input AC voltage, S002 is the first voltage signal, S003 is the external light-on command, S004 is the external light-off command, and S005 is the third drive signal (i.e., the drive signal of the bidirectional thyristor). When the external light-on command S003 is received, the digital controller waits for the voltage of the next first live wire input terminal to cross zero. At the zero-crossing point, the third drive signal S005 is output through the third drive terminal Drv pin via resistor R1 and capacitor C3, so that the bidirectional thyristor is turned on at the voltage zero-crossing point, effectively suppressing surge current and reducing electromagnetic interference.

[0056] When the external light-off command S004 is received, the digital controller waits for the voltage of the first live wire input terminal to cross zero. At the next zero-crossing point, the drive signal of the third drive terminal Drv is removed. The bidirectional thyristor naturally turns off when the current of the first live wire input terminal crosses zero, avoiding voltage spikes and electromagnetic interference.

[0057] If the zero-crossing moment cannot be accurately detected due to an abnormal voltage at the first live wire input terminal, the safety protection logic is activated: when the light is turned on, the thyristor is triggered to conduct after a fixed safety time delay (such as 10ms); when the light is turned off, the drive signal is immediately removed to ensure safe shutdown.

[0058] Second Embodiment The smart switch in this embodiment has two main control switches, such as... Figure 8 As shown, the two main control switches are bidirectional thyristor Q3a and bidirectional thyristor Q3b. Bidirectional thyristor Q3a is connected in series between the first live wire input terminal Lin1 and the reference ground, and bidirectional thyristor Q3b is connected in series between the second live wire input terminal Lin2 and the reference ground, used to independently control the on / off state of the two loads.

[0059] The control circuit for turning on and off bidirectional thyristors Q3a and Q3b is shared. Figure 1 The first switch Q1, the second switch Q2, the first inductor L1, the first diode D1, the first diode D2, and the second capacitor C2 are powered by a shared circuit. Specifically, the two bidirectional thyristors share a common circuit. Figure 1 In the off-state power supply circuit, the on-state power supply circuit needs to be... Figure 1 The bidirectional thyristor Q3 in the circuit is replaced with bidirectional thyristor Q3a and bidirectional thyristor Q3b respectively, while other components are shared.

[0060] In this embodiment, the control circuit can stably draw power regardless of whether a single switch or two switches are turned on simultaneously.

[0061] The control electrode and corresponding drive terminal of the control circuit of the bidirectional thyristor Q3a and Q3b need to be connected to their respective drive modules. The drive modules can be configured as follows: Figure 1 The diagram shows a two-terminal network consisting of a resistor and a capacitor connected in series.

[0062] Third Embodiment The smart switch in this embodiment has three main control switches, such as... Figure 9 As shown, the three main control switches are bidirectional thyristors Q3a, Q3b, and Q3c. Bizontal thyristor Q3a is connected in series between the first live wire input terminal Lin1 and the reference ground. Bizontal thyristor Q3b is connected in series between the second live wire input terminal Lin2 and the reference terminal. Bizontal thyristor Q3c is connected in series between the third live wire input terminal Lin3 and the reference ground, and is used to independently control the on / off state of the three loads.

[0063] The control circuit for turning on and off bidirectional thyristors Q3a, Q3b, and Q3c is shared. Figure 1 The first switch Q1, the second switch Q2, the first inductor L1, the first diode D1, the first diode D2, and the second capacitor C2 are powered by a shared circuit. Specifically, the three bidirectional thyristors share a common circuit. Figure 1 In the off-state power supply circuit, the on-state power supply circuit needs to be... Figure 1 The bidirectional thyristor Q3 in the diagram is replaced with bidirectional thyristors Q3a, Q3b, and Q3c, respectively, while other components are shared.

[0064] In this embodiment, the control circuit can stably draw power in any switching combination state.

[0065] Furthermore, compared to the second embodiment, which requires adding a corresponding drive module between the control electrode of the bidirectional thyristor Q3c and the corresponding drive terminal of the control circuit, this drive module can also be as follows: Figure 1 The diagram shows a two-terminal network consisting of a resistor and a capacitor connected in series.

[0066] This invention can be widely applied to single-wire power supply scenarios such as smart wall switches, smart lighting control systems, and smart home control panels. It offers advantages such as simplified structure, low cost, low loss, reliable power supply, and strong compatibility, demonstrating significant industrial practical value. It should be noted that the above description is merely a preferred embodiment of this application and is not intended to limit the scope of protection of this application. For those skilled in the art, various improvements and modifications can be made to this application without departing from the principles of this application, and these improvements and modifications also fall within the scope of protection of this application.

Claims

1. A single-wire power supply circuit for use in a smart switch, wherein the smart switch includes at least a first live wire input terminal, a live wire output terminal, a first controllable switch (Q3), and a control circuit, wherein the first controllable switch (Q3) is connected in series between the first live wire input terminal and a reference ground, and is controlled by the control circuit to perform on / off actions, characterized in that, The single-wire switch power supply circuit includes: The off-state power supply circuit includes a first diode (D1), a first switching transistor (Q1), a second switching transistor (Q2), a first inductor (L1), a second diode (D2), and a second capacitor (C2) connected in series between the first live wire input terminal and the reference ground. The off-state power supply circuit is used to operate when the first controllable switch (Q3) is turned off. The first switching transistor (Q1) and the second switching transistor (Q2) are controlled by the control circuit to form a stable output voltage across the second capacitor (C2), thereby supplying power to the control circuit. The on-state power supply circuit includes a first controllable switch (Q3), a second switching transistor (Q2), a first inductor (L1), a second diode (D2), and a second capacitor (C2) connected in series between the first live wire input terminal and the reference ground. The on-state power supply circuit is used to operate when the first controllable switch (Q3) is turned on. The first controllable switch (Q3) and the second switching transistor (Q2) are controlled by the control circuit to form a stable output voltage across the second capacitor (C2), thereby supplying power to the control circuit.

2. The single-wire switch power supply circuit according to claim 1, characterized in that: When the power-off circuit is working, the second switch (Q2) remains in the on state, and the first switch (Q1) is controlled by the control circuit to perform high-frequency switching. When the first switch (Q1) is turned on, the current from the first live wire input terminal flows through the first diode (D1), the first switch (Q1), the second switch (Q2), and the first inductor (L1) to the live wire output terminal, where the first inductor (L1) stores energy. When the first switch (Q1) is turned off, the first inductor (L1) releases energy, and the current flows through the second diode (D2), the second capacitor (C2), the second switch (Q2) and back to the first inductor (L1), while the second capacitor (C2) is charged.

3. The single-wire switch power supply circuit according to claim 1, characterized in that: When the power supply circuit is in operation, the first controllable switch (Q3) is turned on, the first switching transistor (Q1) is always turned off, and the second switching transistor (Q2) is controlled by the control circuit to turn on or off. When the output voltage is higher than the second threshold, the second switch (Q2) is turned on, and the current flows in the current path formed by the first live wire input terminal, the first controllable switch (Q3), the second switch (Q2), the first inductor (L1), and the live wire output terminal; When the voltage across the second capacitor (C2) is lower than the first threshold, the second switch (Q2) is turned off, and the current from the live wire output terminal flows through the second diode (D2), the second capacitor (C2), and the first controllable switch (Q3) to the first live wire input terminal to charge the second capacitor (C2).

4. A control circuit, applicable to the single-wire switch power supply circuit according to any one of claims 1 to 3, characterized in that, The control circuit includes: The first driving terminal is used to connect to the control terminal of the first switching transistor (Q1); The second drive terminal is used to connect to the control terminal of the second switching transistor (Q2); The third driving terminal is used to connect to the control terminal of the first controllable switch (Q3); A communication interface or panel button is used to receive instructions to control the first controllable switch (Q3) to perform an on or off action; Memory, used to store programs; A digital controller is configured to respond to the instructions to run the program in order to generate a first control signal, a second control signal, and a third control signal; The first controllable switch driving module generates a third driving signal at the third driving terminal according to the third control signal to drive the first controllable switch (Q3). The drive output module generates a first drive signal at the first drive terminal based on the first control signal to drive the first switch (Q1), and generates a second drive signal at the second drive terminal based on the second control signal to drive the first switch (Q1).

5. The control circuit according to claim 4, characterized in that: The drive output module includes an off-state controller module and an on-state controller module; the off-state controller module generates the first drive signal, and the on-state controller module generates the second drive signal. The first control signal is used to control the power supply of the off-state controller module, and the second control signal is used to control the power supply of the on-state controller module, so that the off-state controller module and the on-state controller module do not operate simultaneously: When the single-wire switch power supply circuit is in the off-state power supply mode, only the off-state controller module is powered on. The first drive signal generated by the off-state controller module controls the first switch (Q1) to perform high-frequency switching, and the second drive signal generated by the on-state controller module controls the second switch (Q2) to remain in the on state. When the single-wire power supply circuit is in the on-state power supply mode, only the on-state controller module is powered on. The first drive signal generated by the off-state controller module controls the first switch (Q1) to remain off. The second drive signal generated by the on-state controller module controls the second switch (Q2) to be turned on or off.

6. The control circuit according to claim 4 or 5, characterized in that: The control circuit also includes an output voltage feedback terminal and an over / under voltage detection module. The over / under voltage detection module is connected to the output voltage through the output voltage feedback terminal and detects whether the output voltage is within a set threshold when the single-wire power supply circuit is in the on-state power supply mode, thereby obtaining an over / under voltage signal. The drive output module controls the second switch (Q2) to be turned on or off according to the over / under voltage signal, so that the voltage across the second capacitor (C2) is within the set threshold.

7. A smart switch, comprising at least a first live wire inlet terminal, a live wire outlet terminal, a first controllable switch (Q3), and a control circuit, wherein the first controllable switch (Q3) is connected in series between the first live wire inlet terminal and a reference ground, and is controlled by the control circuit to perform on / off actions, characterized in that: The smart switch further includes the single-wire power supply circuit according to any one of claims 1 to 3 and the control circuit according to any one of claims 5 to 6.

8. The intelligent switch according to claim 7, characterized in that: The first controllable switch (Q3) is a bidirectional thyristor.

9. The intelligent switch according to claim 7, characterized in that: The bidirectional thyristor is driven by a first controllable switch driving module, which includes a two-terminal network consisting of a first resistor and a third capacitor connected in series. The two-terminal network is connected between the control electrode of the bidirectional thyristor and the third driving terminal of the control circuit.

10. The intelligent switch according to claim 7, characterized in that: The smart switch also includes a first input voltage sampling circuit, and the control circuit also includes an input voltage detection terminal, a bias module and an input voltage detection module. The first input voltage sampling circuit includes a fourth capacitor, a fifth capacitor, and a second resistor. One end of the fourth capacitor is connected to the first live wire input terminal, and the other end of the fourth capacitor is simultaneously connected to one end of the fifth capacitor, one end of the second resistor, and the input voltage detection terminal. The other ends of the fifth capacitor and the other ends of the second resistor are connected to reference ground. The bias module is used to raise the voltage information of the input voltage detection terminal to a first voltage information that meets the internal level requirements of the control circuit. The input voltage detection module is used to identify the zero-crossing moment of the voltage connected to the first live wire input terminal based on the first voltage information and obtain the zero-crossing signal. The digital controller generates a third control signal based on the zero-crossing signal to drive the bidirectional thyristor to conduct at the zero-crossing moment of the voltage at the first live wire input terminal, or removes the third control signal based on the zero-crossing signal to allow the bidirectional thyristor to turn off naturally at the zero-crossing moment of the current at the first live wire input terminal.

11. The intelligent switch according to claim 7, characterized in that: The intelligent switch also includes N controllable switches and N corresponding live wire input terminals, where N is a natural number greater than or equal to 1. The N controllable switches are connected in series between the corresponding live wire input terminal and the reference ground, and are used to independently control the on / off state of N loads. The N controllable switches are controlled by the drive signal output by the corresponding drive terminal of the control circuit to perform conduction and shutdown actions. The control of the N controllable switches and the first controllable switch (Q3) share the off-state power supply circuit. The on-state power supply circuit is shared by replacing the first controllable switch (Q3) with the corresponding controllable switch among the N controllable switches.

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