protection circuit

Abstract

A protection circuit is disclosed, comprising: a contact switch coupled in series in a main circuit and having a terminal proximate to a power source and a terminal proximate to a load, the contact switch configured to control turning on and off of the main circuit; an input device having an input component operable by a user and an output terminal, the input device configured to emit a first signal at the output terminal according to a first operation action of the user on the input component; an on-off execution circuit having a control terminal and configured to perform a turning on action on the contact switch in response to a turning on control signal received at the control terminal, the turning on action comprising actuating the contact switch to an on position; and a controller communicatively coupled to the input device and the on-off execution circuit and configured to receive the first signal from the output terminal of the input device and emit the turning on control signal to the control terminal of the on-off execution circuit according to the first signal.

Description

Technical Field

[0001] This utility model relates to protection circuits, and more specifically to the field of leakage current protection technology. Background Technology

[0002] Existing residual current devices (RCDs) use a single electromagnet for leakage disconnection, and can only perform switching (reset) operations via mechanical structures. The mechanical structure used to switch on (reset) (such as a lever, button, etc.) needs to be directly mechanically connected to the switch. Through this mechanical connection, the user actuates the mechanical structure (e.g., toggles the lever or presses the button) to switch on (reset) the switch. In some space-constrained products, it is difficult to fit too many mechanical components, making implementation challenging. Furthermore, due to the mechanical connection, when a leakage occurs and the disconnection is initiated, the mechanical structure must retract (e.g., the lever or button must spring back). If an external object obstructs this, tripping will fail, and the leakage protection function will not be achieved. To ensure uninterrupted retraction, the mechanical structure would become quite complex and further constrained by space limitations. Utility Model Content

[0003] To address the aforementioned problems, this invention provides a leakage current protection circuit. It uses a DC motor with a reduction gear as the power source to perform the on (reset) and off actions, and a micro-switch to perform the on (reset) and off (test) operations. The structure is simple and effectively solves the problem of the reset button being obstructed by external objects, thus preventing normal operation. The micro-switch does not need to be directly mechanically connected to the switch; instead, it can send signals (e.g., via a controller) to control the motor rotation. This invention eliminates the limitation that the reset device and the switch must be directly mechanically connected.

[0004] In one example, the present invention provides a protection circuit comprising: a contact switch coupled in series in a main circuit and having a terminal near a power source and a terminal near a load, the contact switch being configured to control the connection and disconnection of the main circuit; an input device having an input component operable by a user and an output terminal, the input device being configured to issue a first signal at the output terminal based on a first operation by the user on the input component; an on / off execution circuit having a control terminal and being configured to perform an on action on the contact switch in response to an on control signal received at the control terminal, the on action including actuating the contact switch to an on position; and a controller communicatively coupled to the input device and the on / off execution circuit, and being configured to receive the first signal from the output terminal of the input device and issue the on control signal to the control terminal of the on / off execution circuit based on the first signal.

[0005] In one example, the input device is further configured to issue a second signal at the output terminal based on a second operation by the user on the input component; and the on / off execution circuit is further configured to perform a disconnection action on the contact switch in response to a disconnection control signal received at the control terminal, the disconnection action including actuating the contact switch to an open position; and the controller is further configured to receive the second signal from the output terminal of the input device and issue the disconnection control signal to the control terminal of the on / off execution circuit based on the second signal.

[0006] In one example, the on / off execution circuit is further configured to perform a disconnection action on the contact switch in response to a disconnection control signal received at the control terminal, the disconnection action including actuating the contact switch to an open position; the protection circuit further includes at least one of the following: a temperature detection circuit coupled to the controller and configured to detect the operating ambient temperature of the protection circuit and provide a temperature detection signal indicating the operating ambient temperature to the controller; wherein the controller is further configured to: receive the temperature detection signal from the temperature detection circuit, determine, based on the temperature detection signal, whether the operating ambient temperature has reached an over-temperature setting value, and issue the disconnection control signal to the control terminal of the on / off execution circuit in response to determining that the operating ambient temperature has reached the over-temperature setting value; a leakage current detection circuit coupled to the controller and configured to detect the main circuit... The controller is configured to: receive the leakage detection signal from the leakage detection circuit, determine whether leakage occurs in the main circuit based on the leakage detection signal, and issue the disconnect control signal to the control terminal of the on / off execution circuit in response to determining that leakage occurs in the main circuit; and an overcurrent detection circuit coupled to the controller and configured to detect the current value flowing through the main circuit and provide an overcurrent detection signal indicating the current value to the controller; wherein the controller is further configured to: receive the overcurrent detection signal from the overcurrent detection circuit, determine whether overcurrent occurs in the main circuit based on the overcurrent detection signal, and issue the disconnect control signal to the control terminal of the on / off execution circuit in response to determining that overcurrent occurs in the main circuit.

[0007] In one example, the protection circuit further includes an indicator circuit coupled to the controller or the terminal near the load, and configured to indicate whether the contact switch is in the ON or OFF position.

[0008] In one example, the contact switch includes a conductive spring biased such that the contact switch is in an on or off position when no external force is applied; the on / off actuation circuit includes: a motor coupled to the conductive spring and configured to perform a pressing and releasing action on the conductive spring to perform the on or off action when energized, and remain stationary when de-energized; a motor drive circuit coupled to the motor and the controller and configured to energize the motor in response to the on control signal or the off control signal; and a position detection circuit coupled to the... The controller is configured to detect the position of the contact switch and provide a position detection signal indicating the position of the contact switch to the controller; the controller is further configured to: when the controller is issuing the on control signal, stop issuing the on control signal to the on / off execution circuit in response to the position detection signal indicating that the contact switch is in the on position; or when the controller is issuing the off control signal, stop issuing the off control signal to the on / off execution circuit in response to the position detection signal indicating that the contact switch is in the off position.

[0009] In one example, the position detection circuit includes a switching device having the same structure as the contact switch, a first terminal of the switching device being coupled to a reference voltage node, and a second terminal being coupled to the controller; the motor is also coupled to a conductive spring of the switching device and is configured to perform the on or off action on the switching device while performing the on or off action on the contact switch; and the controller is further configured to determine the position of the switching device based on the voltage received from the second terminal of the switching device, and thus determine the position of the contact switch.

[0010] In one example, the position detection circuit includes a voltage detection circuit coupled to the controller and configured to detect the voltage at the terminal near the load and provide a voltage signal representing the voltage to the controller; and the controller is further configured to determine the position of the contact switch based on the voltage received from the voltage detection circuit.

[0011] In one example, the position detection circuit includes a current detection circuit coupled to the controller and configured to detect the current flowing through the motor and provide a current signal representing the current to the controller; and the controller is further configured to determine the position of the contact switch based on the current received from the current detection circuit.

[0012] In one example, the motor drive circuit includes a transistor with a control terminal coupled to the controller, a first current terminal coupled to a first terminal of the motor, and a second current terminal coupled to a first reference voltage node; and the second terminal of the motor is coupled to a second reference voltage node.

[0013] In one example, the motor drive circuit includes a motor drive chip having a first input terminal, a second input terminal, a first output terminal, and a second output terminal; and the first input terminal and the second input terminal are coupled to the controller, the first output terminal is coupled to a first terminal of the motor, and the second output terminal is coupled to a second terminal of the motor.

[0014] In one example, the detection circuit includes a zero-sequence current transformer (CT1) and a signal processing circuit, wherein the live wire and the neutral wire of the main circuit pass through the zero-sequence current transformer (CT1) simultaneously, the signal processing circuit is coupled to the zero-sequence current transformer (CT1) and configured to process the signal output by the zero-sequence current transformer (CT1) to generate the leakage current detection signal.

[0015] In one example, the overcurrent detection circuit includes a Hall current sensor (U4) or a current sensing resistor (R1).

[0016] In one example, the temperature sensing circuit includes a temperature sensing resistor (RT1).

[0017] In one example, the input device consists of microswitches.

[0018] In one example, the protection circuit also includes a power supply circuit configured to provide the electrical energy required for stable operation of the leakage protection circuit. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the principle of this utility model.

[0020] Figure 2 This is a schematic diagram illustrating the specific implementation principle of Embodiment 1 of this utility model.

[0021] Figure 3 This is a schematic diagram illustrating the specific implementation principle of Embodiment 2 of this utility model.

[0022] Figure 4 This is a schematic diagram illustrating the specific implementation principle of Embodiment 3 of this utility model.

[0023] Figure 5 This is a schematic diagram illustrating the specific implementation principle of Embodiment 4 of this utility model. Detailed Implementation

[0024] like Figure 1 The protection circuit of this application (e.g., a leakage current protection circuit) includes a switching execution circuit, a leakage current detection circuit, an overcurrent detection circuit, a temperature detection circuit, a control circuit (such as a controller), an indicator circuit, an input device, and a power supply circuit. The leakage current detection circuit can detect the leakage current in the main circuit and provide a leakage current detection signal indicating the presence of leakage current to the control circuit. The overcurrent detection circuit can detect the current value flowing through the main circuit and provide an overcurrent detection signal indicating the current value to the control circuit. The temperature detection circuit can detect the operating ambient temperature of the leakage current protection circuit and provide a temperature detection signal indicating the operating ambient temperature to the control circuit. The control circuit can, in response to a received signal (e.g., in response to a leakage current detection signal indicating leakage in the main circuit, in response to an overcurrent detection signal indicating overcurrent in the main circuit, in response to a temperature detection signal indicating that the operating ambient temperature has reached an over-temperature setting value), send a control signal to the switching execution circuit to perform a disconnection action. This disconnection action includes actuating a switch (e.g., a contact switch) in the main circuit to an open state. The switch is coupled in series in the main circuit and has terminals near the power supply and terminals near the load. The contact switch is configured to control the connection and disconnection of the main circuit. The control circuit can also read operating signals from input devices and control the on / off execution circuit to perform the connection or disconnection action based on the operating signals. The indicator circuit indicates whether the on / off execution circuit is in the on or off state and can be implemented in any suitable manner. The power supply circuit can provide the electrical energy required for stable operation of the leakage current protection circuit.

[0025] While the embodiments described in the specification include on / off execution circuits, leakage current detection circuits, overcurrent detection circuits, temperature detection circuits, control circuits, indicator circuits, input devices, and power supply circuits, one or more of these circuits are not essential to all embodiments. For example, some embodiments may not include one or more of the leakage current detection circuit, overcurrent detection circuit, temperature detection circuit, indicator circuit, and power supply circuit. For example, although this invention uses the provision of electrical energy to the protection circuit via a power supply circuit as an example, this invention is not limited thereto. For example, in one example, the various circuits of the protection circuit may be powered by a battery. The battery may take any suitable form, such as a dry cell battery, a button cell battery, a rechargeable battery, a capacitor, etc. Furthermore, although the embodiments in the specification use a circuit between mains power and the electrical equipment as an example, the "main circuit" of this invention may refer to any other power supply circuit. The contact switch of this invention may be any switch that performs on / off switching by contacting and disconnecting contacts. Although the switches in the embodiments of the specification include two switches respectively coupled to the neutral and live wires, this is merely exemplary. The switches of this invention may be coupled only to the live wire, or coupled to a DC circuit, etc. In this invention, the terminal near the power source can refer to the end connected to the power source, and the terminal near the load can refer to the end connected to the load.

[0026] The following embodiments describe in detail specific implementations of the on / off execution circuit, leakage current detection circuit, overcurrent detection circuit, temperature detection circuit, control circuit, indicator circuit, input device, and power supply circuit. It should be understood that these embodiments are merely exemplary and not restrictive.

[0027] Example 1: like Figure 2 The leakage protection circuit includes an on / off execution circuit, a leakage detection circuit, an overcurrent detection circuit, a temperature detection circuit, a control circuit, an indicator circuit, an input device, and a power supply circuit.

[0028] The on / off execution circuit has a port 2 (or control terminal) and is configured to perform an on action on switches S1 and S2 in response to an on control signal received at port 2, the on action including actuating switches S1 and S2 to the on position. The on / off execution circuit is also configured to perform an off action on switches S1 and S2 in response to an off control signal received at port 2, the off action including actuating switches S1 and S2 to the off position.

[0029] In one example, switches S1 and S2 include conductive springs that are biased such that, without external force, switches S1 and S2 are in an on or off position. Switches S1 and S2 can be connected in series in the main circuit.

[0030] The on / off actuation circuit may include a motor coupled to a conductive spring and configured to perform a pressing and releasing action on the conductive spring to perform an on or off action when energized, and remain stationary when de-energized. The on / off actuation circuit also includes a motor drive circuit coupled to the motor and control circuitry and configured to energize the motor in response to an on or off control signal. The on / off actuation circuit also includes a position detection circuit coupled to the control circuitry and configured to detect the positions of switches S1 and S2 and provide position detection signals indicating the positions of switches S1 and S2 to the control circuitry.

[0031] The motor can be a DC motor M1, which may be attached with a reduction gear as a power source to perform pressing and releasing actions on switches S1 and S2 connected in series in the main circuit, thereby realizing the connection and disconnection function of the main circuit. The DC motor M1 (or the reduction gear attached to M1) can be coupled to switches S1 and S2 via the pressing and releasing mechanism. In one example, the pressing and releasing mechanism may include a cam. Rotation of the DC motor M1 causes the cam to rotate, thereby performing the pressing and releasing actions on switches S1 and S2. The reduction gear can amplify the force or torque from the DC motor M1 to promote the rotation of the cam. On the other hand, during the de-energization of the DC motor M1, the force exerted on the cam by the conductive springs of switches S1 and S2 is reduced by the reduction gear, for example, to an amount insufficient to rotate the DC motor M1 (e.g., its rotor). This allows the DC motor M1 to remain stationary when de-energized.

[0032] exist Figure 2 In the illustrated embodiment, the position detection circuit of the on / off execution circuit includes a position detection switch (also referred to as a switching device) S3, which may have the same or similar structure as switches S1 and S2. A first terminal of the position detection switch S3 is coupled to a reference voltage node (e.g., ground), and a second terminal is coupled to the control circuit (e.g., via ports 3 and 8). The DC motor M1 may also be coupled to the conductive spring of the position detection switch S3 and can be configured to perform an on / off action on the position detection switch S3 simultaneously with performing an on / off action on switches S1 and S2. For example, the position detection switch S3 may be provided on a press-and-release mechanism to detect whether a press is complete and whether a release is achieved. The control circuit can determine whether the position detection switch S3 is in the on or off position based on the position detection signal received from port 8, thereby determining whether the on / off action on switches S1 and S2 has been completed.

[0033] exist Figure 2 In the illustrated embodiment, the motor drive circuit of the on / off execution circuit includes a transistor, such as a field-effect transistor (FET) Q1. The DC motor M1 can be controlled to start and stop by the FET Q1. The control terminal of the transistor (e.g., the gate of the FET Q1) is connected to a control circuit, for example, through control circuit port 7. A resistor R6 can be coupled between the gate of the FET Q1 and control circuit port 7. In one example, one end of the resistor R6 is connected to the gate of the FET Q1, and the other end (e.g., through port 2) is connected to the control circuit port 7. The control circuit (e.g., through ports 7 and 2) sends a control signal to the transistor (e.g., the gate of the FET Q1).

[0034] One input terminal (e.g., the positive input terminal) of the DC motor M1 can be connected to a reference voltage node (e.g., the power supply V+ terminal), and the other terminal can be connected to a current terminal of the transistor (e.g., the drain of the field-effect transistor Q1). The other current terminal of the transistor (e.g., the source of the field-effect transistor Q1) is connected to another reference voltage node (e.g., ground).

[0035] In one example, the switching execution circuit also includes a filter circuit. In one implementation, the positive input terminal of the DC motor M1 is connected to one end of inductor L1 and one end of capacitor C3, and its negative input terminal is connected to one end of inductor L2 and one end of capacitor C4. The other end of inductor L1 is connected to the cathode of diode D1, one end of capacitor C5, the positive terminal of capacitor C14, and one end of resistor R17. The other end of inductor L2 is connected to the drain of field-effect transistor Q1, the anode of diode D1, and the other end of capacitor C5. The other end of resistor R17 is connected to a power supply (e.g., the power supply V+ terminal of a power supply circuit) via the power supply V+ terminal to obtain power. The source of field-effect transistor Q1 is connected to the other end of position detection switch S3, the other end of capacitor C3, the other end of capacitor C4, and the negative terminal of capacitor C14, and is connected to a reference voltage node (e.g., ground, as a common ground), and connected to the common ground of the power supply (e.g., the power supply circuit). Capacitor C5 and diode D1 absorb the reverse electromotive force of DC motor M1 and provide freewheeling current when MOSFET Q1 is turned off. Resistor R17 and capacitor C14 form a filter circuit to eliminate or reduce the influence of DC motor M1 on the power supply terminal V+. Inductors L1 and L2, capacitors C3 and C4 form a filter circuit to eliminate or suppress interference generated when DC motor M1 is running.

[0036] In one example, the control circuit is also configured to, when the control circuit is issuing an on control signal, stop issuing on control signals to the on / off execution circuit in response to a position detection signal indicating that switches S1 and S2 are in the on position. For example, it stops sending control signals to the gate of a transistor (e.g., field-effect transistor Q1), causing the transistor to turn off. Immediately after the transistor turns off or after a period of time, the DC motor M1 stops rotating and holds switches S1 and S2 in the on position, for example, by a reduction gear and a press-and-release mechanism (e.g., a cam).

[0037] In another example, the control circuit is also configured to, when the control circuit is issuing a disconnect control signal, stop issuing disconnect control signals to the on / off execution circuit in response to a position detection signal indicating that switches S1 and S2 are in the disconnected position. For example, it stops sending control signals to the transistor (e.g., the gate of the field-effect transistor Q1), causing the transistor to turn off. Immediately after the transistor turns off or after a period of time, the DC motor M1 stops rotating and holds switches S1 and S2 in the disconnected position, for example, by a reduction gear and a press-and-release mechanism (e.g., a cam).

[0038] In one example, the on and off control signals can be similar signals. For instance, both the on and off control signals can cause the motor to rotate. Sending an on control signal can cause the DC motor M1 to rotate to a position where S1 and S2 are on (e.g., by means of feedback from a position detection circuit, such as a position detection signal). Sending an off control signal can cause the DC motor M1 to rotate to a position where S1 and S2 are off (e.g., by means of feedback from a position detection circuit, such as a position detection signal).

[0039] The leakage current detection circuit is coupled to the control circuit and configured to detect the leakage current in the main circuit and provide a leakage current detection signal indicating the presence of leakage current to the control circuit. The control circuit is also configured to: receive the leakage current detection signal from the leakage current detection circuit, determine whether leakage current has occurred in the main circuit based on the leakage current detection signal, and issue a disconnection control signal to port 2 of the on / off execution circuit in response to determining that leakage current has occurred in the main circuit.

[0040] exist Figure 2In the illustrated embodiment, the leakage current detection circuit uses a zero-sequence current transformer CT1 for leakage current detection. The live wire and neutral wire of the main circuit pass through the zero-sequence current transformer CT1 simultaneously through input ports L3 and N5, and are output to the electrical equipment through output ports L4 and N6. When leakage occurs, the current flowing through the live wire and neutral wire is unbalanced, and the current transformer outputs a signal. The signal is amplified by operational amplifier U2 and sent to the control circuit for reading and judgment. Output terminal 1 of current transformer CT1 is connected to the cathode of diode D3, the anode of diode D4, and one end of resistor R8. Diodes D3 and D4 provide amplitude limiting protection. The other end of resistor R8 is connected to the negative input terminal of operational amplifier U2, one end of resistor R14, and one end of capacitor C13. The other end of capacitor C13 is connected to one end of resistor R13. The other end of resistor R13 is connected to the other end of resistor R14, the output terminal of operational amplifier U2, and one end of capacitor C10. The other end of capacitor C10 is connected to one end of resistor R11 and one end of resistor R15 as the output terminal after signal amplification, and is connected to port 9 of the control circuit through port 4 to transmit the detected leakage signal to the control circuit for reading and judgment. The other end of R11 is connected to the positive terminal of the power supply of operational amplifier U2, one end of capacitor C9, and one end of resistor R9 as the power supply V+ terminal, and is connected to the power supply V+ terminal of the power supply circuit to obtain power. The other end of resistor R9 is connected to the positive input terminal of operational amplifier U2, one end of resistor R12, and one end of capacitor C12 to provide a reference voltage for operational amplifier U2. The output terminal 2 of current transformer CT1 is connected to the anode of diode D3, the cathode of diode D4, the other end of capacitor C12, the other end of resistor R12, the negative terminal of the power supply of operational amplifier U2, the other end of capacitor C9, and the other end of resistor R15, and is connected to a reference voltage node (e.g., ground, as a common ground), and is connected to the common ground of the power supply circuit.

[0041] The overcurrent detection circuit is coupled to the control circuit and configured to detect the current value flowing through the main circuit and provide an overcurrent detection signal indicating the current value to the control circuit. The control circuit is also configured to: receive the overcurrent detection signal from the overcurrent detection circuit, determine whether an overcurrent has occurred in the main circuit based on the overcurrent detection signal, and issue a disconnection control signal to port 2 of the on / off execution circuit in response to determining that an overcurrent has occurred in the main circuit.

[0042] exist Figure 2In the illustrated embodiment, the overcurrent detection circuit uses a current-sensing resistor R1 to detect the current flowing through the main circuit. The current-sensing resistor R1 is connected in series with the neutral line N of the main circuit. The AC current flowing through the sensing resistor R1 generates positive and negative voltage drops across it, causing fluctuations in the voltage division between resistors R18 and R16. The control circuit determines whether an overcurrent has occurred based on the read voltage fluctuation values. One end of the current-sensing resistor R1 is connected to one end of resistor R16 and to the mains neutral line N through port N1; its other end is connected to one end of capacitor C2 and to a reference voltage node (e.g., ground, as a common ground), and to the common ground of the power supply circuit. It is also connected to the input port N3 of the on / off execution circuit through port N2. The other end of resistor R16 is connected to the other end of capacitor C2 and one end of resistor R18, and to port 6 of the control circuit through port 1, providing the detected current signal to the control circuit for reading and judgment. The other end of resistor R18 is connected to the power supply V+ terminal of the power supply circuit to obtain power.

[0043] The temperature detection circuit is coupled to the control circuit and configured to detect the operating ambient temperature of the protection circuit and provide a temperature detection signal indicating the operating ambient temperature to the control circuit. The control circuit is also configured to: receive the temperature detection signal from the temperature detection circuit, determine whether the operating ambient temperature has reached an over-temperature setting value based on the temperature detection signal, and, in response to determining that the operating ambient temperature has reached the over-temperature setting value, issue a disconnection control signal to port 2 of the on / off execution circuit.

[0044] exist Figure 2 In the illustrated embodiment, the temperature detection circuit uses a thermistor RT1 to detect the ambient temperature. One end of the temperature detection resistor RT1 is connected to one end of resistor R21, and is connected to port 14 of the control circuit via port 15. The resistance value of the detection circuit RT1 changes with the ambient temperature, causing the voltage at port 15 to also change with the ambient temperature. This allows the control circuit to read the ambient temperature change value and determine whether to perform over-temperature protection based on the temperature value. The other end of resistor R21 is connected to the power supply V+ terminal of the power supply circuit to obtain power. The other end of the thermistor RT1 is connected to a reference voltage node (e.g., ground, as a common ground) and is also connected to the common ground of the power supply circuit.

[0045] exist Figure 2In the illustrated embodiment, the control circuit uses an MCU with an ADC to read and process signals, and output control signals. The MCU's VCC pin is connected to one end of capacitor C7, and it obtains power through the V+ terminal of the power supply circuit. Its AD1_IO11 pin is connected to port 1 of the overcurrent detection circuit via port 6 to read the current detection signal and determine if an overcurrent has occurred. If an overcurrent occurs, a disconnect signal is output through pin IO00. Its IO00 pin is connected to port 2 of the on / off execution circuit via port 7 to control the on / off execution circuit to perform on or off operations. Its AD2_IO12 pin is connected to port 3 of the on / off execution circuit via port 8 to read the position signal of the pressing and releasing mechanism driven by the DC motor M1, and to determine whether the on / off operation of the on / off execution circuit has been executed correctly. Pin 3_IO13 is connected to port 4 of the leakage detection circuit via port 9, reads the leakage detection signal, determines whether leakage has occurred, and notifies pin IO00 to output a disconnect signal when leakage occurs; its IO01 pin is connected to port 11 of the indicator circuit via port 10, and sends an on or off signal to the indicator circuit; its AD0_IO10 pin is connected to port 15 of the temperature detection circuit via port 14, reads the temperature detection signal, determines whether over-temperature has occurred, and outputs a disconnect signal via pin IO00 when over-temperature occurs; its IO02 pin is connected to port 13 of the input device via port 12, reads the operation signal of the input device, and outputs an on or off signal via pin IO00 according to the operation signal. The MCU's GND pin is connected to the other end of capacitor C7 and connected to a reference voltage node (e.g., ground, as a common ground), and connected to the common ground of the power supply circuit.

[0046] The control circuit described above is merely exemplary, and the control circuit of this invention can be any suitable hardware. For example, the control circuit can be implemented by one or more integrated circuits, logic circuits, FPGAs, microprocessors, CPUs, GPUs, DSPs, or microcontrollers from any desired family or manufacturer. The control circuit can be implemented by one or more semiconductor-based (e.g., silicon-based) devices. The control circuit can also be implemented in software or a combination of software and hardware.

[0047] The indicator circuit is coupled to the control circuit or a terminal near the load (as shown below). Figure 5 As shown), and configured to indicate whether switches S1 and S2 are in the ON or OFF position.

[0048] exist Figure 2In the illustrated embodiment, the indicating circuit uses LED1 to indicate the on / off state of the switching execution circuit. When LED1 is lit, it indicates that the switching execution circuit is on; when LED1 is off, it indicates that the switching execution circuit is off. The anode of LED1 is connected to one end of resistor R20, and its cathode is connected to a reference voltage node (e.g., grounded, as a common ground) and to the common ground of the power supply circuit. The other end of resistor R20 is connected to port 10 of the control circuit through port 11 to obtain the control voltage for LED1 to light up or turn off.

[0049] The input device has user-operable input components and output terminals. The input device is configured to emit a corresponding signal at the output terminals based on the user's operation of the input components. In one example, this operation could be a command to turn on switches S1 and S2, and therefore the corresponding signal would cause the control circuit to command the on / off execution circuit to turn on switches S1 and S2. In another example, the operation could be a command to turn off switches S1 and S2, and therefore the corresponding signal would cause the control circuit to command the on / off execution circuit to turn off switches S1 and S2.

[0050] The control circuit is communicatively coupled to the input device and the on / off execution circuit, and is configured to receive the signal from the output terminal of the input device and, based on the signal, issue a corresponding control signal to port 2 of the on / off execution circuit. In one example, the signal is one that causes the control circuit to command the on / off execution circuit to turn on switches S1 and S2, and the corresponding control signal is an on control signal. The on / off execution circuit actuates switches S1 and S2 to the on position in response to the on control signal received at port 2. In another example, the signal is one that causes the control circuit to command the on / off execution circuit to turn off switches S1 and S2, and the corresponding control signal is a off control signal. The on / off execution circuit actuates switches S1 and S2 to the off position in response to the off control signal received at port 2.

[0051] exist Figure 2 In the illustrated embodiment, the input device is composed of a micro switch S4. Different operations on the micro switch S4 output a power-on or power-off command. One end of the micro switch S4 is connected to the control circuit port 12 via port 13, and the other end is connected as a common terminal to the common terminal of the power supply circuit. The micro switch S4 is merely exemplary; the input device of this application can include any suitable type of device.

[0052] exist Figure 2In the illustrated embodiment, the power supply circuit consists of a low standby power non-isolated step-down constant voltage chip U1 and peripheral components. It rectifies the mains power half-wave and then steps it down, stabilizing the stepped-down DC voltage to the required DC voltage value for its load circuit operation. One end of fuse F1 is connected to the mains live wire L via port 5 to obtain power input. Its other end is connected to one end of varistor RV1 and the anode of diode D5. The cathode of diode D5 is connected to one end of resistor R19. The other end of resistor R19 is connected to one end of capacitor C6 and one end of inductor L3. The other end of inductor L3 is connected to the positive terminal of capacitor C15 and the DRAIN pin of chip U1. This circuit provides surge protection, rectification, and electromagnetic filtering for the mains power. The VCC pin of chip U1 is connected to one end of capacitor C8. The FB pin of chip U1 is connected to one end of resistors R2 and R3. The four GNG pins of chip U1 are connected to the other ends of resistor R2, capacitor C8, the cathode of diode D2, and one end of inductor L4. The other end of resistor R3 is connected to one end of resistor R4. The other end of resistor R4 is connected to the other end of inductor L4, the positive terminal of capacitor C16, and one end of resistor R7 as the power supply V+ terminal. The other end of varistor RT1 is connected to the other end of C6, the negative terminal of C15, the anode of diode D2, the negative terminal of capacitor C16, and the other end of resistor R7, and is connected to a reference voltage node (e.g., ground, as a common ground).

[0053] Example 2 like Figure 3 As shown, its difference from Embodiment 1 lies in the on / off execution circuit, the power supply circuit, and the control circuit.

[0054] exist Figure 3 In the illustrated embodiment, the motor drive chip includes a motor drive chip (e.g., DC motor drive chip U4), which replaces the field-effect transistor Q1 in Embodiment 1 to drive the DC motor M1, performing rotation and stopping actions. The motor drive chip has a first input terminal INA (also referred to as the INA pin), a second input terminal INB (also referred to as the INB pin), a first output terminal OUTA (also referred to as the OUTA pin), and a second output terminal OUTB (also referred to as the OUTB pin). The INA pin and the INB pin are coupled to the control circuit (e.g., via ports 2, 20, 7, and 21). The OUTA pin is coupled to the first terminal (e.g., the positive input terminal) of the DC motor M1, and the OUTB pin is coupled to the second terminal (e.g., the negative input terminal) of the DC motor M1. The drive chip U4 can realize the forward and reverse rotation control of the DC motor M1. In conjunction with the position detection switch S3, the activation execution circuit can perform the activation operation faster and more accurately.

[0055] exist Figure 3In the illustrated embodiment, the switching execution circuit further includes a filtering circuit. In one example, the OUTA pin of the driver chip U4 is connected to the other end of inductor L1 and one end of capacitor C5, and the OUTB pin of the driver chip U4 is connected to the other end of inductor L2 and the other end of capacitor C5, enabling forward and reverse power supply to the DC motor M1 to achieve forward and reverse rotation control. The INA pin of the driver chip U4 is connected to one end of resistor R42 and is connected to the control circuit port 21 through port 20. The INB pin of the driver chip U4 is connected to one end of resistor R41 and is connected to the control circuit port 7 through port 2, receiving the forward and reverse rotation control signals from the control circuit. The VDD pin of the driver chip U4 is connected to the positive terminal of capacitor C14 as the power supply V+ terminal and is connected to the power supply V+ terminal of the power supply circuit to obtain power. The GND pin of the driver chip is connected to the negative terminal of capacitor C14, the other end of resistor R41, and the other end of resistor R42, and is connected to a reference voltage node (e.g., ground, as a common ground), and connected to the common ground of the power supply circuit.

[0056] exist Figure 3 In the illustrated embodiment, a three-terminal voltage regulator chip U5 is added to the power supply V+ terminal of Embodiment 1. The output of the three-terminal voltage regulator chip U5 is used as the power supply V+ terminal, making the power supply more stable and cleaner, and improving the stability and accuracy of the load circuit. The VI pin of the three-terminal voltage regulator chip U5 is connected to the other end of resistor R4, the other end of inductor L4, the positive terminal of capacitor C16, and one end of resistor R7. The VO pin of the three-terminal voltage regulator chip is connected to the positive terminal of capacitor C46 as the power supply V+ terminal. The GND pin of the three-terminal voltage regulator chip is connected to the negative terminal of capacitor C46 and the common ground.

[0057] The MCU of the control circuit has an additional I / O control pin IO04 compared to that in Embodiment 1. It is connected to the on / off execution circuit port 20 through port 21. Combined with the original I / O control pin IO00, it controls the forward and reverse rotation of the DC motor M1 of the on / off execution circuit to achieve precise execution of on and off operations.

[0058] Example 3 like Figure 4 The difference between this embodiment and Embodiment 1 lies in the overcurrent detection circuit and the on / off execution circuit.

[0059] exist Figure 4In the illustrated embodiment, the overcurrent detection circuit uses a Hall current sensor U6 instead of the current sensing resistor R1 used in Embodiment 1 for current detection, which can effectively reduce the power consumption caused by the current sensing resistor R1 and reduce internal heat generation. The two input pins IP+ of the Hall current sensor U6 are connected to the neutral line of the mains power supply through port N1, and the other two input pins IP- are connected to port N3 of the on / off execution circuit through port N2. Its output pin OUT is connected to one end of resistor R31, and the other end of R31 is connected to one end of capacitor C32 as a current detection signal output, which is connected to port 6 of the control circuit through port 1, allowing the control circuit to read and judge the signal. Its VCC pin is connected to one end of capacitor C31, and is connected to the power supply V+ terminal of the power supply circuit to obtain power. Its GND pin is connected to capacitor C31 and connected to a reference voltage node (e.g., ground, as a common ground), and is connected to the common ground of the power supply circuit.

[0060] exist Figure 4 In the illustrated embodiment, the position detection circuit includes a voltage detection circuit coupled to the control circuit and configured to detect the voltage at a terminal near the load and provide a voltage signal representing the voltage to the control circuit. The control circuit is also configured to determine the positions of switches S1 and S2 based on the voltage received from the voltage detection circuit.

[0061] In one example, the on / off detection of the on / off execution circuit is performed by detecting the output voltage of the on / off execution circuit. The presence of output voltage indicates on, and the absence of output voltage indicates off. This method is more direct and stable than using the position detection switch S3 in Example 1. The voltage detection circuit uses optocoupler OP1 for isolated detection. Input pin 1 of optocoupler OP1 is connected to one end of capacitor C33 and then to output port L2. Input pin 2 of optocoupler OP1 is connected to the other end of capacitor C33 and one end of resistor R32. The other end of R32 is connected to output port N4, thus detecting the output voltage of the on / off execution circuit. Output pin 3 of optocoupler OP1 is connected to one end of resistor R33 and one end of capacitor C34 as a detection signal output. This signal is connected to port 8 of the control circuit via port 3, allowing the control circuit to read and judge the detection signal. Output pin 4 of optocoupler OP1 is connected to one end of capacitor C35 and is connected to the power supply V+ terminal of the power supply circuit to obtain power. The other end of capacitor C35 is connected to the other end of resistor R33 and the other end of capacitor C34, and then connected to the common ground.

[0062] Example 4 like Figure 5 As shown, its difference from Embodiment 1 lies in the on / off execution circuit, the leakage current detection circuit, the indicator circuit, the input device, and the control circuit.

[0063] exist Figure 5 In the illustrated embodiment, the position detection circuit includes a current detection circuit coupled to the control circuit and configured to detect the current flowing through the DC motor M1 and provide a current signal representing that current to the control circuit. The control circuit is also configured to determine the positions of switches S1 and S2 based on the current received from the current detection circuit.

[0064] In one example, the on / off execution circuit determines whether the circuit is on or off by detecting the operating current of the DC motor M1, eliminating the position detection switch S3 in Embodiment 1, resulting in a simpler structure. One end of the current sensing resistor R10 is connected to the source of the MOSFET Q1 and one end of resistor R5 to detect the current flowing through the MOSFET Q1, which is also the operating current of the DC motor M1. The other end of R5 is connected to one end of capacitor C11 as a detection signal output, which is connected to port 8 of the control circuit through port 3, allowing the control circuit to read and judge the detection signal. The other end of the current sensing resistor R10 is connected to the other end of resistor C11 and then connected to a common ground.

[0065] exist Figure 5 In the illustrated embodiment, the leakage current detection circuit uses a window comparator U7 instead of the operational amplifier U2 in Embodiment 1 for leakage current detection. When the AC output signal of the zero-sequence current transformer CT1 reaches the threshold voltage set by the window comparator U7, the window comparator U7 outputs a level signal for the control circuit to read directly. This is faster than using an analog output signal for the control circuit to read using an ADC, thus improving the leakage current disconnection response speed. Output pin 1 of the zero-sequence current transformer CT1 is connected to the cathode of diode D3, the anode of diode D4, and one end of resistor R23. The other end of resistor R23 is connected to one end of resistor R22, one end of capacitor C22, and the input pin UVIN of the window comparator U7. Output pin 2 of the zero-sequence current transformer CT1 is connected to the anode of diode D3, the cathode of diode D4, and one end of resistor R24. The other end of resistor R24 ​​is connected to one end of resistor R25, the other end of capacitor C22, and the input pin OVIN of the window comparator U7. The output pins / UV and / OV of window comparator U7, along with one end of resistor R21, are connected to output a detection signal. This signal is then connected to port 9 of the control circuit via port 4, allowing the control circuit to read and interpret the detection signal. The other end of resistor R22 is connected to the power supply pin VCC of window comparator U7, the other end of resistor R21, and one end of capacitor C9. This power supply is then connected to the power supply V+ terminal of the power supply circuit to obtain power. The other end of resistor R25 is connected to the ground pin GND of window comparator U7 and the other end of capacitor C9, and is also connected to a reference voltage node (e.g., ground, as a common ground), thus connecting to the common ground of the power supply circuit.

[0066] exist Figure 5 In the illustrated embodiment, the indicating circuit indicates the on / off state by directly detecting the output port of the on / off execution circuit. When the on / off execution circuit is on, the indicating circuit LED2 lights up. When the on / off execution circuit is off, the indicating circuit LED2 turns off. This is more reliable and stable than the indirect control of the indicating circuit LED to indicate the on / off state of the on / off execution circuit via the control circuit in Embodiment 1. The indicating circuit LED2 is a bidirectional LED, with its pin 1 connected to one end of resistor R26, and the other end of R26 connected to the output port L2 of the on / off execution circuit; its pin 2 is connected to the output port N4 of the on / off execution circuit.

[0067] exist Figure 5 In the illustrated embodiment, the input device adds a micro-switch S5 compared to Embodiment 1. The on / off operation is performed using a separate micro-switch, making operation simpler and more convenient. One end of the micro-switch S5 is connected to the control circuit port 16 via port 17, and the other end is connected to the common ground.

[0068] The MCU of the control circuit removes the control pin IO01 of the indicator circuit and adds the signal input pin IO03 of the input device. Pin IO03 is connected to port 17 of the input controller through port 16.

[0069] The terms “coupled”, “connected”, etc., can encompass (wired or wireless) connections, communication, or signal paths that achieve a functional relationship consistent with this invention. For example, if device A generates a signal to control device B to perform an action: (A) in the first example, device A is coupled to device B via a direct connection; or (b) in the second example, if the intervening component C does not change the functional relationship between device A and device B, then device A is coupled to device B via the intervening component C, such that device B is controlled by the control signal generated by device A.

[0070] A device "configured" to perform a task or function can be configured by the manufacturer at manufacturing time (e.g., programming and / or hardwiring) to perform that function, and / or can be user-configurable (or reconfigurable) after manufacturing to perform that function and / or other additional or alternative functions. Configuration can be done through firmware and / or software programming of the device, through the construction and / or layout of the device's hardware components and interconnections, or a combination thereof.

[0071] As used herein, the terms “terminal,” “port,” “node,” “interconnect,” “pin,” and “lead” are used interchangeably. Unless specifically stated otherwise, these terms are generally used to refer to interconnections or terminations between device elements, circuit elements, integrated circuits, devices, or other electronic or semiconductor components.

[0072] The terms "comprising" and "including" are used in this document as open-ended terms. Therefore, whenever a claim uses "comprising" or "including," additional elements, features, etc., may be present without exceeding the scope of the corresponding claim or description.

[0073] Within the scope of the claims, modifications to the described examples are possible, and other examples are also possible.

Claims

1. A protection circuit, characterized in that, include: A contact switch, which is coupled in series in a main circuit and has a terminal near the power source and a terminal near the load, is configured to control the connection and disconnection of the main circuit. An input device having an input component operable by a user and an output terminal, the input device being configured to emit a first signal at the output terminal based on a first operation by the user on the input component; An on / off execution circuit has a control terminal and is configured to perform an on action on the contact switch in response to an on control signal received at the control terminal, the on action including actuating the contact switch to an on position; as well as A controller communicatively coupled to the input device and the on / off execution circuit, and configured to receive the first signal from the output terminal of the input device and, based on the first signal, issue the on / off control signal to the control terminal of the on / off execution circuit.

2. The protection circuit according to claim 1, characterized in that, The input device is further configured to issue a second signal at the output terminal based on a second operation by the user on the input component; and the on / off execution circuit is further configured to perform a disconnection action on the contact switch in response to a disconnection control signal received at the control terminal, the disconnection action including actuating the contact switch to an open position; and the controller is further configured to receive the second signal from the output terminal of the input device and issue the disconnection control signal to the control terminal of the on / off execution circuit based on the second signal.

3. The protection circuit according to claim 1, characterized in that, The on / off execution circuit is further configured to perform a disconnection action on the contact switch in response to a disconnection control signal received at the control terminal, the disconnection action including actuating the contact switch to the disconnected position; The protection circuit also includes at least one of the following: A temperature detection circuit, coupled to the controller and configured to detect the operating ambient temperature of the protection circuit and provide a temperature detection signal indicating the operating ambient temperature to the controller; wherein the controller is further configured to: receive the temperature detection signal from the temperature detection circuit, determine, based on the temperature detection signal, whether the operating ambient temperature has reached an over-temperature setting value, and, in response to determining that the operating ambient temperature has reached the over-temperature setting value, issue the disconnection control signal to the control terminal of the on / off execution circuit; A leakage current detection circuit, coupled to the controller and configured to detect leakage current in the main circuit and provide a leakage current detection signal indicating the presence of leakage current to the controller; wherein the controller is further configured to: receive the leakage current detection signal from the leakage current detection circuit, determine whether leakage current occurs in the main circuit based on the leakage current detection signal, and issue the disconnection control signal to the control terminal of the on / off execution circuit in response to determining that leakage current occurs in the main circuit; as well as An overcurrent detection circuit, coupled to the controller and configured to detect the current value flowing through the main circuit and provide an overcurrent detection signal indicating the current value to the controller; wherein the controller is further configured to: receive the overcurrent detection signal from the overcurrent detection circuit, determine whether an overcurrent has occurred in the main circuit based on the overcurrent detection signal, and issue the disconnection control signal to the control terminal of the on / off execution circuit in response to determining that an overcurrent has occurred in the main circuit.

4. The protection circuit according to claim 1, characterized in that, Also includes: An indicator circuit, coupled to the controller or the terminal near the load, is configured to indicate whether the contact switch is in the ON or OFF position.

5. The protection circuit according to claim 1, characterized in that, The on / off execution circuit is further configured to perform a disconnection action on the contact switch in response to a disconnection control signal received at the control terminal, the disconnection action including actuating the contact switch to the disconnected position; The contact switch includes a conductive spring, which is biased such that the contact switch is in the on or off position when no external force is applied. The on / off execution circuit includes: A motor coupled to the conductive spring and configured to perform a pressing and releasing action on the conductive spring to perform the on or off action when energized, and to remain stationary when de-energized; A motor drive circuit coupled to the motor and the controller, and configured to energize the motor in response to the on control signal or the off control signal; A position detection circuit, coupled to the controller, is configured to detect the position of the contact switch and provide a position detection signal indicating the position of the contact switch to the controller. The controller is also configured to: When the controller is issuing the on / off control signal, in response to the position detection signal indicating that the contact switch is in the on position, the controller stops issuing the on / off control signal to the on / off execution circuit; or When the controller is issuing the disconnect control signal, in response to the position detection signal indicating that the contact switch is in the disconnect position, the controller stops issuing the disconnect control signal to the on / off execution circuit.

6. The protection circuit according to claim 5, characterized in that, The position detection circuit includes a switching device having the same structure as the contact switch, wherein a first terminal of the switching device is coupled to a reference voltage node and a second terminal is coupled to the controller; The motor is also coupled to the conductive spring of the switching device and is configured to perform the connecting or disconnecting action on the switching device simultaneously with performing the connecting or disconnecting action on the contact switch; and The controller is also configured to determine the position of the switching device based on the voltage received from the second terminal of the switching device, and thus determine the position of the contact switch.

7. The protection circuit according to claim 5, characterized in that, The position detection circuit includes a voltage detection circuit coupled to the controller and configured to detect the voltage at the terminal near the load and provide a voltage signal representing the voltage to the controller. and The controller is also configured to determine the position of the contact switch based on the voltage received from the voltage detection circuit.

8. The protection circuit according to claim 5, characterized in that, The position detection circuit includes a current detection circuit coupled to the controller and configured to detect the current flowing through the motor and provide a current signal representing the current to the controller. and The controller is also configured to determine the position of the contact switch based on the current received from the current detection circuit.

9. The protection circuit according to claim 5, characterized in that, The motor drive circuit includes a transistor, the control terminal of which is coupled to the controller, the first current terminal of which is coupled to the first terminal of the motor, and the second current terminal of which is coupled to the first reference voltage node. Furthermore, the second terminal of the motor is coupled to the second reference voltage node.

10. The protection circuit according to claim 5, characterized in that, The motor drive circuit includes a motor drive chip, which has a first input terminal, a second input terminal, a first output terminal, and a second output terminal; and The first input terminal and the second input terminal are coupled to the controller, the first output terminal is coupled to the first terminal of the motor, and the second output terminal is coupled to the second terminal of the motor.

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