Driving circuit and direct-current residual current detection system

Abstract

The utility model provides a drive circuit and a DC residual current detection system. The drive circuit comprises a first voltage follower; the input end of the first voltage follower is used for accessing a driving voltage, the output end of the first voltage follower is electrically connected with the first end of the direct current residual current transformer, and the second end of the direct current residual current transformer is used for accessing a reference voltage; the driving voltage is the voltage in which the first level state and the second level state change periodically, the amplitude of the driving voltage in the first level state is larger than that of the reference voltage, and the amplitude of the driving voltage in the second level state is smaller than that of the reference voltage. The two ends of the direct-current residual current transformer can have a voltage difference with the direction changing periodically, and then the direct-current residual current transformer can obtain the corresponding direct-current residual current based on magnetic field coupling of the direct-current residual current. According to the utility model, a threshold value does not need to be set, so that many technical problems of the existing scheme adopting the threshold value are solved.

Description

Technical Field

[0001] This utility model relates to the field of circuit breaker technology, specifically to a drive circuit and a DC residual current detection system. Background Technology

[0002] Residual current circuit breakers (RCCBs) are important protective devices specifically designed to provide protection against both direct and indirect electric shock. They are widely used in various electrical applications, including industrial, commercial, high-rise buildings, and residential buildings, and offer significant advantages such as compact size, ease of operation, high breaking capacity, and high reliability. A core component of RCCBs is their reliable detection of residual current.

[0003] For the detection of DC residual current, most existing solutions use fluxgate magnetization to couple the magnetic field of the DC residual current into the magnetic field generated by a hardware-based excitation circuit. The DC residual current is detected by detecting changes in the magnetic field. In the excitation circuit, to allow the DC residual current transformer to periodically excite and demagnetize, two threshold thresholds are often designed, causing the excitation voltage of the DC residual current transformer to reverse promptly after reaching these two thresholds. This approach has the following drawbacks: it is cumbersome to debug, requiring repeated adjustments to the thresholds; it is prone to positive and negative current asymmetry during DC residual current detection; and when detecting large residual currents, the large magnetic field of the residual current can prevent the excitation voltage of the transformer from reaching the threshold, thus failing to detect the residual current correctly. Utility Model Content

[0004] In view of the shortcomings of the existing technology, this utility model provides a driving circuit and a DC residual current detection system.

[0005] In one embodiment, the present invention provides a driving circuit, which includes a first voltage follower.

[0006] The input terminal of the first voltage follower is used to connect the driving voltage, the output terminal of the first voltage follower is electrically connected to the first terminal of the DC residual current transformer, and the second terminal of the DC residual current transformer is used to connect the reference voltage.

[0007] The driving voltage is a voltage that changes periodically between a first level state and a second level state. When the driving voltage is in the first level state, its amplitude is greater than the reference voltage, and when the driving voltage is in the second level state, its amplitude is less than the reference voltage.

[0008] In one embodiment, the driving circuit further includes a reference voltage generation unit;

[0009] The input terminal of the reference voltage generating unit is used to connect to the working voltage, and the output terminal of the reference voltage generating unit is electrically connected to the second terminal of the DC residual current transformer.

[0010] The reference voltage generation unit is used to output a reference voltage to the second terminal of the DC residual current transformer based on the input operating voltage.

[0011] In one embodiment, the reference voltage generating unit includes a voltage divider subunit and a second voltage follower;

[0012] The input terminal of the voltage divider unit is used to connect the working voltage. The output terminal of the voltage divider unit is electrically connected to the input terminal of the second voltage follower. The output terminal of the second voltage follower is electrically connected to the second terminal of the DC residual current transformer.

[0013] In one embodiment, the voltage divider subunit includes a first voltage divider resistor and a second voltage divider resistor;

[0014] The first end of the first voltage divider resistor is used to connect to the working voltage. The second end of the first voltage divider resistor is electrically connected to the input terminal of the second voltage follower and the first end of the second voltage divider resistor, respectively. The second end of the second voltage divider resistor is used to ground.

[0015] Secondly, in one embodiment, the present invention provides a DC residual current detection system, which includes a DC residual current transformer, a controller, a sampling circuit, and a driving circuit as described in any of the above embodiments.

[0016] The power supply terminal of the controller is used to connect to the working voltage. The first output terminal of the controller is electrically connected to the input terminal of the first voltage follower. The input terminal of the controller is electrically connected to the output terminal of the sampling circuit. The input terminal of the sampling circuit is electrically connected to the second terminal of the DC residual current transformer.

[0017] DC residual current transformers are used to be installed on power lines.

[0018] In one embodiment, the sampling circuit includes a filter resistor and a filter capacitor;

[0019] The first end of the filter resistor is electrically connected to the second end of the DC residual current transformer. The second end of the filter resistor is electrically connected to the first end of the filter capacitor and the input end of the controller. The second end of the filter capacitor is used for grounding.

[0020] In one embodiment, the DC residual current detection system further includes a tripping circuit;

[0021] The tripping circuit is electrically connected to the second output terminal of the controller and is used to control the tripping mechanism connected in series on the power line to trip according to the tripping signal output by the controller.

[0022] In one embodiment, the tripping circuit includes a tripping coil and a switching unit;

[0023] The first end of the trip coil is used to connect to the working voltage, the second end of the trip coil is electrically connected to the first input end of the switching unit, the second input end of the switching unit is used to ground, and the controlled end of the switching unit is electrically connected to the second output end of the controller.

[0024] The trip coil is used to control the tripping state of the tripping mechanism based on its current state.

[0025] In one embodiment, the switching unit includes a transistor;

[0026] The base of the transistor is electrically connected to the second output terminal of the controller, the collector of the transistor is electrically connected to the second terminal of the trip coil, and the emitter of the transistor is used for grounding.

[0027] In one embodiment, the DC residual current detection system further includes a power supply circuit;

[0028] The input terminal of the power supply circuit is electrically connected to the power line, and the output terminal of the power supply circuit is electrically connected to the power supply terminal of the controller.

[0029] The power supply circuit is used to output the operating voltage to the controller based on the power supply voltage on the power line.

[0030] Through the aforementioned driving circuit and DC residual current detection system, a first voltage follower is set up, and its input terminal is connected to a driving voltage with periodically varying amplitude, which is output to the first terminal of the DC residual current transformer. Combined with the reference voltage connected to the second terminal of the DC residual current transformer, a voltage difference with periodically varying direction can exist across the two terminals of the DC residual current transformer. This allows the DC residual current transformer to obtain the corresponding DC residual current based on the magnetic field coupling of the DC residual current. This invention does not require setting a threshold, does not require frequent debugging, is less prone to problems of positive and negative current asymmetry, and avoids the problem of DC residual current not being detectable due to the large magnetic field of the DC residual current failing to reach the threshold. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the drive circuit in one embodiment of the present invention;

[0033] Figure 2 This is a schematic diagram of the structure of the driving circuit in one embodiment of the present invention, which further includes a voltage divider subunit and a second voltage follower.

[0034] Figure 3 This is a schematic diagram of the specific circuit implementation of the driving circuit in one embodiment of the present invention;

[0035] Figure 4 This is a schematic diagram of the DC residual current detection system in one embodiment of the present invention;

[0036] Figure 5 This is a schematic diagram of the specific circuit including the sampling circuit in one embodiment of the present invention. Detailed Implementation

[0037] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0038] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified. In this application, the term "exemplary" is used to mean "used as an example, illustration, or description." Any embodiment described as "exemplary" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to implement and use this invention. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that this invention can be implemented without using these specific details. In other instances, well-known structures and processes will not be described in detail to avoid obscuring the description of this invention with unnecessary detail. Therefore, this invention is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.

[0039] Firstly, such as Figure 1 As shown, in one embodiment, the present invention provides a driving circuit, which includes a first voltage follower.

[0040] The input terminal of the first voltage follower is used to connect to the driving voltage DRV, the output terminal of the first voltage follower is electrically connected to the first terminal of the DC residual current transformer, and the second terminal of the DC residual current transformer is used to connect to the reference voltage REFV.

[0041] Among them, the DC residual current transformer is used to be installed on the power line (such as the live wire L and the neutral wire N) to achieve magnetic field coupling based on the DC residual current on the power line.

[0042] The first voltage follower ensures impedance matching between the input and output, thereby improving the driving capability and ensuring reliable transmission of the driving voltage.

[0043] The driving voltage DRV is a voltage that changes periodically between a first level state and a second level state. When the driving voltage DRV is in the first level state, its amplitude is greater than that of the reference voltage REFV, and when the driving voltage DRV is in the second level state, its amplitude is less than that of the reference voltage REFV.

[0044] It can be understood that the driving voltage DRV can be a square wave with a certain duty cycle, and the first and second level states of the driving voltage DRV are low and high, respectively. When the driving voltage DRV is high, the corresponding amplitude is greater than the reference voltage REFV; when the driving voltage DRV is low, the corresponding amplitude is less than the reference voltage REFV.

[0045] Specifically, when the amplitude of the driving voltage DRV is greater than the reference voltage REFV, the voltage difference across the DC residual current transformer is characterized by the first terminal being greater than the second terminal, which can be understood as the first voltage difference direction, with current flowing from the first terminal to the second terminal. When the amplitude of the driving voltage DRV is less than the reference voltage REFV, the voltage difference across the DC residual current transformer is characterized by the second terminal being greater than the first terminal, which can be understood as the second voltage difference direction, with current flowing from the second terminal to the first terminal. When the level of the driving voltage DRV changes periodically, the voltage difference across the DC residual current transformer also changes periodically in the first and second voltage difference directions, thus enabling it to complete the periodic excitation and demagnetization process, thereby obtaining the corresponding DC residual current in the magnetic field coupling of the DC residual current.

[0046] Through the aforementioned driving circuit, a first voltage follower is configured, and its input terminal is connected to a driving voltage with periodically varying amplitude, which is then output to the first terminal of the DC residual current transformer. Combined with the reference voltage connected to the second terminal of the DC residual current transformer, a voltage difference with periodically varying direction exists across the two terminals of the DC residual current transformer. This allows the DC residual current transformer to obtain the corresponding DC residual current based on the magnetic field coupling of the DC residual current. This invention eliminates the need for setting threshold values, frequent adjustments, and the problem of positive and negative current asymmetry. It also avoids the problem of the DC residual current failing to be detected due to the large magnetic field of the DC residual current preventing the threshold value from being reached.

[0047] In one embodiment, the driving circuit further includes a reference voltage generation unit;

[0048] The input terminal of the reference voltage generation unit is used to connect to the working voltage VCC, and the output terminal of the reference voltage generation unit is electrically connected to the second terminal of the DC residual current transformer.

[0049] The reference voltage generation unit is used to output a reference voltage REFV to the second terminal of the DC residual current transformer based on the input operating voltage VCC.

[0050] The reference voltage REFV can be directly connected, but in this embodiment, a dedicated reference voltage generation unit can also be set up to obtain the required reference voltage REFV more accurately and flexibly.

[0051] like Figure 2 As shown, in one embodiment, the reference voltage generation unit includes a voltage divider unit and a second voltage follower.

[0052] The input terminal of the voltage divider unit is used to connect to the working voltage VCC, the output terminal of the voltage divider unit is electrically connected to the input terminal of the second voltage follower, and the output terminal of the second voltage follower is electrically connected to the second terminal of the DC residual current transformer.

[0053] The magnitude of the reference voltage REFV depends on the connected operating voltage VCC and the voltage division ratio of the voltage divider subunit.

[0054] In this embodiment, the reference voltage REFV can also be obtained by dividing the working voltage VCC by the voltage divider subunit. However, in order to ensure impedance matching between the input and output, thereby improving the driving capability and ensuring reliable transmission of the reference voltage, a second voltage follower is further provided.

[0055] like Figure 3 As shown, in one embodiment, the first voltage follower is composed of operational amplifier U3B, resistor R10 and resistor R11, the second voltage follower is composed of operational amplifier U3A, resistor R5 and resistor R6, and the voltage divider subunit includes a first voltage divider resistor R8 and a second voltage divider resistor R9.

[0056] The first terminal of the first voltage divider resistor R8 is used to connect to the working voltage VCC (such as V5V working voltage), the second terminal of the first voltage divider resistor R8 is electrically connected to the non-inverting input terminal of the operational amplifier U3A and the first terminal of the second voltage divider resistor R9, and the second terminal of the second voltage divider resistor R9 is used to ground.

[0057] The inverting input terminal of the operational amplifier U3A is electrically connected to the output terminal of the operational amplifier U3A through resistor R5, and is electrically connected to the second terminal CT2 of the DC residual current transformer through resistor R6.

[0058] The non-inverting input of operational amplifier U3B is connected to the driving voltage DRV through resistor R11, and the inverting input of operational amplifier U3B is electrically connected to the output of operational amplifier U3B through resistor R10 and electrically connected to the first terminal CT1 of the DC residual current transformer.

[0059] The input drive voltage DRV can be 5V at its high level and 0V at its low level. The resistance values ​​of the first voltage divider resistor R8 and the second voltage divider resistor R9 can be equal. Thus, the reference voltage REFV output by operational amplifier U3A is always approximately 2.5V. When the drive voltage DRV is high, the output voltage of operational amplifier U3B is approximately 5V, and the voltage at the first terminal CT1 of the DC residual current transformer is greater than that at the second terminal CT2, causing current to flow from the first terminal CT1 to the second terminal CT2. When the drive voltage DRV is low, the output voltage of operational amplifier U3B is approximately 0V, and the voltage at the first terminal CT1 of the DC residual current transformer is less than that at the second terminal CT2, causing current to flow from the second terminal CT2 to the first terminal CT1.

[0060] like Figure 3 As shown, in one embodiment, the voltage divider unit further includes a capacitor C12.

[0061] Among them, capacitor C12 is used for filtering to ensure the stability of the voltage output to operational amplifier U3A.

[0062] Secondly, such as Figure 4 As shown, in one embodiment, the present invention provides a DC residual current detection system, which includes a DC residual current transformer, a controller, a sampling circuit, and a driving circuit as described in any of the above embodiments.

[0063] The controller's power supply terminal is connected to the operating voltage through the power supply circuit. The controller's first output terminal IO3 is electrically connected to the input terminal of the first voltage follower in the drive circuit to output the drive voltage. The controller's input terminal ADC is electrically connected to the output terminal of the sampling circuit. The input terminal of the sampling circuit is electrically connected to the second terminal of the DC residual current transformer.

[0064] The controller includes, but is not limited to, an MCU.

[0065] The controller outputs a corresponding driving voltage to the drive circuit, thereby realizing the changing excitation of the DC residual current transformer, so that the DC residual current transformer can obtain the corresponding DC residual current based on the magnetic field coupling of the DC residual current.

[0066] The controller also obtains the current on the DC residual current transformer through a sampling circuit. It should be noted that the current obtained by the sampling circuit is actually the superposition of the DC residual current induced by the DC residual current transformer and the changing excitation applied by the drive circuit. Therefore, after the controller obtains the current fed back by the sampling circuit, it still needs to remove the changing excitation applied to the DC residual current transformer by the drive circuit to finally obtain the accurate DC residual current.

[0067] By using the driving circuit in the aforementioned DC residual current detection system, a first voltage follower is set up, and its input terminal is connected to a driving voltage with periodically varying amplitude. The output voltage is then sent to the first terminal of the DC residual current transformer. Combined with the reference voltage connected to the second terminal of the DC residual current transformer, a voltage difference with periodically varying direction exists across the two terminals of the DC residual current transformer. This allows the DC residual current transformer to obtain the corresponding DC residual current based on the magnetic field coupling of the DC residual current. This invention eliminates the need for setting a threshold, frequent adjustments, and the problem of positive and negative current asymmetry. It also avoids the problem of the DC residual current failing to be detected due to the large magnetic field of the DC residual current preventing the threshold from being reached.

[0068] like Figure 5 As shown, in one embodiment, the sampling circuit includes a filter resistor R7 and a filter capacitor C10.

[0069] The first terminal of the filter resistor R7 is electrically connected to the second terminal CT2 of the DC residual current transformer. The second terminal of the filter resistor R7 is electrically connected to the first terminal of the filter capacitor C10 and the input terminal of the controller, respectively, to output the sampling voltage SENSE that represents the sampled current. The second terminal of the filter capacitor C10 is used for grounding.

[0070] Among them, the filter resistor R7 and the filter capacitor C10 constitute an RC filter circuit to ensure the reliability of the output sampling voltage SENSE.

[0071] like Figure 4 As shown, in one embodiment, the DC residual current detection system further includes a trip circuit, which includes a trip coil and a switching unit composed of a transistor Q1.

[0072] The first end of the trip coil is connected to the working voltage through the power supply circuit, the second end of the trip coil is electrically connected to the collector of transistor Q1, the emitter of transistor Q1 is grounded, and the base of transistor Q1 is electrically connected to the second output terminal IO1 of the controller.

[0073] The trip unit consists of a trip coil and a tripping mechanism on the power line. The trip coil controls the tripping state of the tripping mechanism based on its current state. For example, when there is current in the trip coil, it generates magnetic force, which drives the tripping mechanism to perform a tripping operation, thereby disconnecting the power line to protect the safety of downstream loads and personnel. At this time, the tripping state of the tripping mechanism is "performing tripping".

[0074] Specifically, when the controller determines that the residual DC current on the current power line is too large based on the sampling voltage fed back by the sampling circuit, it outputs a high-level trip signal to transistor Q1. Transistor Q1 is turned on, and the working voltage connected to the trip coil can form a current loop to ground after passing through the trip coil and transistor Q1, so there is current in the trip coil.

[0075] In other embodiments, the switching unit may also employ other switching devices besides transistor Q1.

[0076] like Figure 4 As shown, in one embodiment, the DC residual current detection system further includes a power supply circuit.

[0077] The input terminal of the power supply circuit is electrically connected to the power line, and the output terminal of the power supply circuit is electrically connected to the power supply terminal of the controller and the first terminal of the trip coil, respectively.

[0078] The power supply circuit is used to output operating voltage to the controller and trip coil respectively according to the power supply voltage on the power line.

[0079] In this embodiment, power is drawn directly from the power line through the power supply circuit, without the need for additional energy storage devices such as batteries.

[0080] It is important to note that the amplitude of the operating voltage required by the trip coil is usually different from that required by the controller. Therefore, the power supply circuit needs to be able to output two different amplitude operating voltages. For example, a two-stage step-down structure can be used, with the voltage obtained from the first stage step-down serving as the operating voltage of the trip coil and the voltage obtained from the second stage step-down serving as the operating voltage of the controller.

[0081] As mentioned in the above embodiments, the driving circuit usually needs to be connected to the operating voltage. In this embodiment, the operating voltage of the driving circuit can be obtained from the power supply circuit or from the controller.

[0082] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the detailed descriptions of other embodiments above, which will not be repeated here.

[0083] The above provides a detailed description of the driving circuit and DC residual current detection system provided by this utility model. Specific examples have been used to illustrate the principle and implementation of this utility model. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​this utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​this utility model. Therefore, the content of this specification should not be construed as a limitation of this utility model.

[0084] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A driving circuit, characterized in that, The driving circuit includes a first voltage follower; The input terminal of the first voltage follower is used to connect to the driving voltage, the output terminal of the first voltage follower is electrically connected to the first terminal of the DC residual current transformer, and the second terminal of the DC residual current transformer is used to connect to the reference voltage. The driving voltage is a voltage that periodically changes between a first level state and a second level state. The amplitude of the driving voltage in the first level state is greater than the reference voltage, and the amplitude of the driving voltage in the second level state is less than the reference voltage.

2. The driving circuit according to claim 1, characterized in that, The driving circuit also includes a reference voltage generation unit; The input terminal of the reference voltage generating unit is used to connect to the working voltage, and the output terminal of the reference voltage generating unit is electrically connected to the second terminal of the DC residual current transformer. The reference voltage generating unit is used to output the reference voltage to the second terminal of the DC residual current transformer according to the input operating voltage.

3. The driving circuit according to claim 2, characterized in that, The reference voltage generating unit includes a voltage divider subunit and a second voltage follower; The input terminal of the voltage divider subunit is used to connect to the working voltage, the output terminal of the voltage divider subunit is electrically connected to the input terminal of the second voltage follower, and the output terminal of the second voltage follower is electrically connected to the second terminal of the DC residual current transformer.

4. The driving circuit according to claim 3, characterized in that, The voltage divider subunit includes a first voltage divider resistor and a second voltage divider resistor; The first end of the first voltage divider resistor is used to connect to the working voltage. The second end of the first voltage divider resistor is electrically connected to the input terminal of the second voltage follower and the first end of the second voltage divider resistor, respectively. The second end of the second voltage divider resistor is used to ground.

5. A DC residual current detection system, characterized in that, The DC residual current detection system includes a DC residual current transformer, a controller, a sampling circuit, and a driving circuit as described in any one of claims 1 to 4. The power supply terminal of the controller is used to connect to the working voltage. The first output terminal of the controller is electrically connected to the input terminal of the first voltage follower. The input terminal of the controller is electrically connected to the output terminal of the sampling circuit. The input terminal of the sampling circuit is electrically connected to the second terminal of the DC residual current transformer. The DC residual current transformer is used to be installed on the power line.

6. The DC residual current detection system according to claim 5, characterized in that, The sampling circuit includes a filter resistor and a filter capacitor; The first end of the filter resistor is electrically connected to the second end of the DC residual current transformer, the second end of the filter resistor is electrically connected to the first end of the filter capacitor and the input end of the controller, and the second end of the filter capacitor is used for grounding.

7. The DC residual current detection system according to claim 5 or 6, characterized in that, The DC residual current detection system also includes a tripping circuit; The tripping circuit is electrically connected to the second output terminal of the controller and is used to control the tripping mechanism connected in series on the power line to trip according to the tripping signal output by the controller.

8. The DC residual current detection system according to claim 7, characterized in that, The tripping circuit includes a tripping coil and a switching unit; The first end of the trip coil is used to connect to the working voltage, the second end of the trip coil is electrically connected to the first input terminal of the switching unit, the second input terminal of the switching unit is used to ground, and the controlled terminal of the switching unit is electrically connected to the second output terminal of the controller. The trip coil is used to control the tripping state of the tripping mechanism according to its current state.

9. The DC residual current detection system according to claim 8, characterized in that, The switching unit includes a transistor; The base of the transistor is electrically connected to the second output terminal of the controller, the collector of the transistor is electrically connected to the second terminal of the trip coil, and the emitter of the transistor is used for grounding.

10. The DC residual current detection system according to claim 5 or 6, characterized in that, The DC residual current detection system also includes a power supply circuit; The input terminal of the power supply circuit is electrically connected to the power line, and the output terminal of the power supply circuit is electrically connected to the power supply terminal of the controller. The power supply circuit is used to output a working voltage to the controller based on the power supply voltage on the power line.

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