Electronic miniature circuit breaker circuit board

Abstract

The application discloses an electronic type small circuit breaker circuit board, which comprises a circuit board body, wherein a power supply circuit, a logic processing circuit, a current sampling circuit, a voltage sampling circuit, a reference voltage circuit, an LED lamp indicating circuit, an over-zero detection belt circuit, a key detection circuit and a relay control circuit are arranged on the circuit board body, and the power supply circuit is connected with the logic processing circuit, the current sampling circuit, the voltage sampling circuit, the reference voltage circuit, the LED lamp indicating circuit, the over-zero detection belt circuit, the key detection circuit and the relay control circuit respectively. Compared with the prior art, the circuit board has the instantaneous and current overload performance of the traditional circuit breaker, and can solve the current protection which is lacked by the existing over-voltage and under-voltage protector. The circuit breaker is added with electronic control in the closing process, the circuit breaker can actively monitor the voltage waveform, and is closed when the voltage is zero, so that the inrush current caused by the closing of the traditional circuit breaker is greatly reduced, and the damage risk of the equipment is reduced.

Description

Technical Field

[0001] This invention relates to the field of low-voltage electrical technology, and more particularly to a circuit board for an electronic miniature circuit breaker. Background Technology

[0002] Existing overvoltage and undervoltage circuit breakers provide overcurrent protection, which mainly involves determining whether a fault has occurred in the load downstream of the circuit breaker.

[0003] Traditional thermal-magnetic circuit breakers lack voltage monitoring capabilities. Voltage monitoring involves monitoring the power grid voltage, enabling timely disconnection to protect the load in case of overvoltage or undervoltage hazards. Traditional circuit breakers cannot identify voltage waveform signals during closing, failing to guarantee closing at the voltage zero-crossing point, and also cannot guarantee opening at the current zero-crossing point. Furthermore, their mechanical lifespan is limited to tens of thousands of cycles, making them unsuitable for scenarios requiring frequent closing and opening. Their electrical lifespan, when operating under load (ranging from several thousand to tens of thousands of cycles), is also inconsistent, making them unsuitable for locations requiring frequent load-based closing and opening.

[0004] Therefore, the present invention needs to provide a device that has the instantaneous and current overload performance of a traditional circuit breaker, and can solve the current protection lacking in existing over / under voltage protectors. Summary of the Invention

[0005] The purpose of this invention is to provide an electronic miniature circuit breaker circuit board, thereby solving the aforementioned problems existing in the prior art.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] An electronic miniature circuit breaker circuit board includes a circuit board body, on which a power supply circuit, a logic processing circuit, a current sampling circuit, a voltage sampling circuit, a reference voltage circuit, an LED indicator circuit, a zero-crossing detection circuit, a key detection circuit, and a relay control circuit are provided. The power supply circuit is connected to the logic processing circuit, the current sampling circuit, the voltage sampling circuit, the reference voltage circuit, the LED indicator circuit, the zero-crossing detection circuit, the key detection circuit, and the relay control circuit, respectively.

[0008] The current sampling circuit, voltage sampling circuit, and zero-crossing detection circuit are connected in parallel and then connected to the logic processing circuit. The LED indicator circuit, reference voltage circuit, and key detection circuit are all connected to the logic processing circuit. The logic processing circuit is connected to the relay control circuit.

[0009] The power supply circuit is used to convert the input AC mains power into smooth low-voltage DC power. This DC power VCC1 provides the driving voltage to the relay drive module. VCC1 is stepped down twice to become VCC2. VCC2 supplies power to the key detection circuit, zero-crossing detection circuit, LED indicator circuit, reference voltage circuit, voltage sampling circuit, current sampling circuit and logic processing circuit.

[0010] The logic processing circuit is used to implement voltage zero-crossing logic recognition, current zero-crossing logic recognition, LED light-up control logic, key recognition logic, main circuit current calculation, and closing / opening logic control; it also processes current signals to calculate the actual current value and implements current protection logic; and processes voltage signals to calculate the actual voltage value and implements voltage protection logic.

[0011] The current sampling circuit is used to convert the current signal into a voltage signal that can be recognized by the logic processing circuit through the operational amplifier circuit.

[0012] The voltage sampling circuit is used to convert the voltage signal into a voltage signal that can be recognized by the logic processing circuit through the operational amplifier circuit;

[0013] The reference voltage circuit is used to convert the supply voltage VCC2 into a reference voltage VCC3;

[0014] The LED indicator circuit is used to indicate the status of the circuit breaker;

[0015] The zero-crossing detection circuit is used to determine the current zero-crossing signal;

[0016] The key detection circuit is used to detect the action status of external keys;

[0017] The relay control circuit is used to control the relay operation through a logic processing circuit.

[0018] Furthermore, the width of the circuit board body is 18 mm.

[0019] Furthermore, the power supply circuit includes: terminals J1 and J2, the AC input terminal of the power supply is input from terminals J1 and J2, a varistor RV1 is connected in parallel between terminals J1 and J2, the varistor RV1 is connected in parallel with resistor R3, and resistor R3 is connected in series with the AC1 terminal of the rectifier bridge.

[0020] The DC+ terminal of the rectifier bridge is connected in parallel with the positive terminal of capacitor C4, the negative terminal of capacitor C4 is connected in parallel with the DC- terminal of the rectifier bridge, the positive terminal of capacitor C4 is connected to pins 7 and 8 of chip U2, pin 4 of chip U2 is connected in parallel with the positive terminal of capacitor C5 and in series with diode D3, the anode of diode D3 is connected in parallel with inductor L1 and in parallel with the positive terminal of capacitor C3, the negative terminal of capacitor C3 is connected in series with the anode of freewheeling diode D4, the negative terminal of diode D4 is connected in parallel with inductor L1 and in parallel with the negative terminal of capacitor C5, the negative terminal of capacitor C5 is connected to pins 1 and 2 of chip U2, the anode of diode D1 is connected to resistor R4, diode D1 is connected in parallel with the positive terminal of capacitor C1 and is connected to pin 3 of chip U1, pin 2 of chip U1 is connected to the negative terminal of capacitor C1, and pin 1 of chip U1 is connected to capacitor C2.

[0021] Furthermore, the logic processing circuit uses a domestically produced MCU as the main chip, U3.

[0022] Furthermore, the current sampling circuit includes: terminal P2, through which the current transformer signal is input; terminal P2 is connected in series with resistor R13, through which the secondary current of the transformer is converted into voltage; resistor R13 is connected in parallel with resistors R11 and R14 and then connected to pins 9 and 10 of chip U4C; resistor R16 is connected in parallel with resistor R14 and pin 10 of chip U4C; resistor R9 is connected in parallel with capacitor C6 and then connected to pin 8 of chip U4C and connected in series with resistor R12; the other end of resistor R12 is connected to pin 10 of logic processing circuit U3.

[0023] Furthermore, the voltage sampling circuit includes: terminal P3, through which the voltage signal is input; the two pins of terminal P3 are connected to resistors R21 and R24 respectively; resistors R21 and R22 are connected in series; resistors R24 and R25 are connected in series; one end of resistor R26 is connected to the reference voltage VCC3, and the other end is connected to pin 3 of chip U4A; one end of resistor R19 is connected to resistor R22 and pin 1 of chip U4A; resistor R23 is connected to pin 1 of chip U4A, and the other end is connected to pin 11 of logic processing circuit U3.

[0024] Furthermore, the reference voltage circuit includes a resistor R28, one end of which is connected to the supply voltage VCC2, and the other end is connected to the cathode of the voltage regulator Q7. Capacitors C9 and C10 are connected in parallel with the voltage regulator Q7. Pin 12 of the chip U4D is connected to capacitor C10, and pin 14 of the chip U4D outputs the reference voltage VCC3.

[0025] Furthermore, the LED indicator circuit includes: a resistor R10, one end of which is connected to the power supply VCC2, and the other end is connected to the positive terminal of the light-emitting diode D5. The negative terminal of the light-emitting diode is connected to pin 38 of the logic processing circuit U3. A resistor R15 is connected to the power supply VCC2, and the other end is connected to the positive terminal of the light-emitting diode D6. The negative terminal of the light-emitting diode is connected to pin 39 of the logic processing circuit U3.

[0026] Furthermore, the zero-crossing detection circuit includes: a resistor R29, one end of which is connected to the reference voltage VCC3 and the other end of which is connected to pin 6 of the chip U4B; a resistor R31, one end of which is connected to the current signal and the other end of which is connected to pin 5 of the chip U4B; pin 7 of the chip U4B is connected to a resistor R30; and the other end of which is connected to pin 12 of the logic processing circuit U3.

[0027] Furthermore, the button detection circuit includes: a resistor R20, one end of which is connected to pin 39 of the logic processing circuit U3 and the other end is connected to the TVS transistor D7; a resistor R18 is connected to the power supply VCC2 and the other end is connected in series with a capacitor C7; and a light touch button S1 is connected in parallel with a capacitor C7.

[0028] Furthermore, the relay control circuit includes a resistor R5 connected to the base of transistor Q5 and to pin 42 of logic processing circuit chip U3, a collector of transistor connected to resistor R1, and the other end of resistor R1 connected to the base of transistor Q1. Transistor Q1's emitter is connected to power supply VCC1. Transistor Q1's collector is connected to transistor Q6's collector. Transistor Q6's emitter is connected to power supply ground. Transistor Q6's base is connected to resistor R7. The other end of resistor R7 is connected to resistor R6 and to pin 43 of logic processing chip U3. Resistor R6 is connected to transistor Q4's base. Transistor Q4's collector is connected to resistor R2. The other end of resistor R2 is connected to transistor Q2's base. Transistor Q2's emitter is connected to power supply VCC1. Transistor Q2's collector is connected to transistor Q3's collector. Transistor Q3's emitter is connected to power supply ground. Resistor R8 is connected to transistor Q3's base. Connector P1 is connected to transistors Q1 and Q6's collectors respectively. Connector P1 is also connected to transistors Q2 and Q3's collectors respectively.

[0029] The beneficial effects of this invention are:

[0030] The electronic miniature circuit breaker circuit board of this invention incorporates electronic control during the circuit breaker tripping process, thereby enabling monitoring of the main circuit current and tripping when the current crosses zero, effectively suppressing the generation of electric arcs. The tripping and closing uses magnetic latching relays, and the mechanical life of the relays can reach 200,000 cycles, allowing this product to work in scenarios requiring frequent tripping and closing.

[0031] By incorporating electronic control into the circuit breaker's closing process, the circuit breaker can actively monitor the voltage waveform and close the circuit when the voltage crosses zero, greatly reducing the surge current caused by traditional circuit breakers during closing and lowering the risk of equipment damage. Attached Figure Description

[0032] Figure 1 This is a diagram showing the circuit board module composition of the electronic miniature circuit breaker of the present invention;

[0033] Figure 2 This is a circuit diagram of the power supply circuit of the present invention;

[0034] Figure 3 This is a circuit diagram of the logic processing circuit of the present invention;

[0035] Figure 4 This is a circuit diagram of the current sampling circuit of the present invention;

[0036] Figure 5 This is a circuit diagram of the voltage sampling circuit of the present invention;

[0037] Figure 6 This is a circuit diagram of the reference voltage circuit of the present invention;

[0038] Figure 7 This is a circuit diagram of the LED indicator of the present invention;

[0039] Figure 8 This is a circuit diagram of the zero-crossing detection circuit of the present invention;

[0040] Figure 9 This is a circuit diagram of the key detection circuit of the present invention;

[0041] Figure 10 This is a circuit diagram of the relay control circuit of the present invention;

[0042] Figure 11 This is a flowchart illustrating the operation of the electronic miniature circuit breaker of this invention. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0044] It should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the present invention or 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. Therefore, they should not be construed as limitations on the present invention.

[0045] 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 technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0046] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0047] Furthermore, to better illustrate this application, numerous specific details are provided in the following detailed embodiments. Those skilled in the art should understand that this application can be implemented without certain specific details. In some instances, methods, means, components, and circuits well-known to those skilled in the art have not been described in detail in order to highlight the main points of this application.

[0048] like Figures 1 to 10 As shown, this invention relates to an electronic miniature circuit breaker circuit board, comprising a circuit board body, on which are provided a power supply circuit, a logic processing circuit, a current sampling circuit, a voltage sampling circuit, a reference voltage circuit, an LED indicator circuit, a zero-crossing detection band circuit, a key detection circuit, and a relay control circuit. The power supply circuit is connected to the logic processing circuit, the current sampling circuit, the voltage sampling circuit, the reference voltage circuit, the LED indicator circuit, the zero-crossing detection band circuit, the key detection circuit, and the relay control circuit, respectively.

[0049] The current sampling circuit, voltage sampling circuit, and zero-crossing detection circuit are connected in parallel and then connected to the logic processing circuit. The LED indicator circuit, reference voltage circuit, and key detection circuit are all connected to the logic processing circuit. The logic processing circuit is connected to the relay control circuit.

[0050] The power supply circuit is used to convert the input AC mains power into smooth low-voltage DC power. This DC power VCC1 provides the driving voltage to the relay drive module. VCC1 is stepped down twice to become VCC2. VCC2 supplies power to the key detection circuit, zero-crossing detection circuit, LED indicator circuit, reference voltage circuit, voltage sampling circuit, current sampling circuit and logic processing circuit.

[0051] The logic processing circuit is used to implement voltage zero-crossing logic recognition, current zero-crossing logic recognition, LED light-up control logic, key recognition logic, main circuit current calculation, and closing / opening logic control; it also processes current signals to calculate the actual current value and implements current protection logic; and processes voltage signals to calculate the actual voltage value and implements voltage protection logic.

[0052] The current sampling circuit is used to convert the current signal into a voltage signal that can be recognized by the logic processing circuit through the operational amplifier circuit.

[0053] The voltage sampling circuit is used to convert the voltage signal into a voltage signal that can be recognized by the logic processing circuit through the operational amplifier circuit;

[0054] The reference voltage circuit is used to convert the supply voltage VCC2 into a reference voltage VCC3;

[0055] The LED indicator circuit is used to indicate the status of the circuit breaker;

[0056] The zero-crossing detection circuit is used to determine the current zero-crossing signal;

[0057] The key detection circuit is used to detect the action status of external keys;

[0058] The relay control circuit is used to control the relay operation through a logic processing circuit.

[0059] As can be seen from the above, over / under voltage protection not only replaces commercially available over / under voltage protectors but also features zero-voltage closing and zero-current segmentation, making it particularly suitable for applications requiring frequent switching. Unlike traditional circuit breakers, this invention uses a relay as the primary carrier for connecting and disconnecting the main circuit, exhibiting electronically controlled characteristics. The addition of current detection effectively replicates the thermal-magnetic protection of traditional circuit breakers. Therefore, this invention not only replaces traditional circuit breakers but also significantly reduces the impact on the load.

[0060] In this embodiment, the width of the circuit board body is set to 18mm, which greatly saves the space of the distribution box.

[0061] Specifically, the power supply circuit includes: terminals J1 and J2, the AC input terminal of the power supply is input from terminals J1 and J2, a varistor RV1 is connected in parallel between terminals J1 and J2, the varistor RV1 is connected in parallel with resistor R3, and resistor R3 is connected in series with the AC1 terminal of the rectifier bridge.

[0062] The DC+ terminal of the rectifier bridge is connected in parallel with the positive terminal of capacitor C4, the negative terminal of capacitor C4 is connected in parallel with the DC- terminal of the rectifier bridge, the positive terminal of capacitor C4 is connected to pins 7 and 8 of chip U2, pin 4 of chip U2 is connected in parallel with the positive terminal of capacitor C5 and in series with diode D3, the anode of diode D3 is connected in parallel with inductor L1 and in parallel with the positive terminal of capacitor C3, the negative terminal of capacitor C3 is in series with the anode of freewheeling diode D4, the negative terminal of diode D4 is connected in parallel with inductor L1 and in parallel with the negative terminal of capacitor C5, the negative terminal of capacitor C5 is connected to pins 1 and 2 of chip U2, the anode of diode D1 is connected to resistor R4, diode D1 is connected in parallel with the positive terminal of capacitor C1 and in pin 3 of chip U1, pin 2 of chip U1 is connected to the negative terminal of capacitor C1, and pin 1 of chip U1 is connected to capacitor C2. The function of the power supply module is to convert the input AC mains power into smooth low-voltage DC power. This DC power VCC1 provides the driving voltage for the relay drive module. VCC1 is stepped down twice to become VCC2, which powers the key detection circuit, zero-crossing detection circuit, LED indicator circuit, reference voltage circuit, voltage sampling circuit, current sampling circuit, and logic processing circuit.

[0063] In this embodiment, the logic processing circuit uses a domestically produced MCU (MCU) as the main chip U3 to implement voltage zero-crossing logic recognition, current zero-crossing logic recognition, LED lighting control logic, button recognition logic, main circuit current calculation, and closing / opening logic control. It processes the current signal to calculate the actual current value, thus implementing current protection logic. It also processes the voltage signal to calculate the actual voltage value, thus implementing voltage protection logic.

[0064] Furthermore, the current sampling circuit includes: terminal P2, through which the current transformer signal is input; terminal P2 is connected in series with resistor R13, through which the secondary current of the transformer is converted into voltage; resistor R13 is connected in parallel with resistors R11 and R14 and then connected to pins 9 and 10 of chip U4C; resistor R16 is connected in parallel with resistor R14 and pin 10 of chip U4C; resistor R9 is connected in parallel with capacitor C6 and then connected to pin 8 of chip U4C and connected in series with resistor R12; the other end of resistor R12 is connected to pin 10 of logic processing circuit U3. The function of the current sampling circuit is to convert the current signal into a voltage signal that can be recognized by the logic processing circuit through the operational amplifier circuit.

[0065] Another noteworthy feature is that the voltage sampling circuit includes: terminal P3, through which the voltage signal is input; the two pins of terminal P3 are connected to resistors R21 and R24 respectively; resistors R21 and R22 are connected in series; resistors R24 and R25 are connected in series; one end of resistor R26 is connected to the reference voltage VCC3, and the other end is connected to pin 3 of chip U4A; one end of resistor R19 is connected to resistor R22 and pin 1 of chip U4A; resistor R23 is connected to pin 1 of chip U4A, and the other end is connected to pin 11 of logic processing circuit U3. The voltage sampling circuit converts the voltage signal into a voltage signal that the logic processing circuit can recognize through the operational amplifier circuit.

[0066] In addition, this embodiment also includes a reference voltage circuit, which includes a resistor R28. One end of the resistor R28 is connected to the supply voltage VCC2, and the other end is connected to the cathode of the voltage regulator Q7. Capacitors C9 and C10 are connected in parallel with the voltage regulator Q7. Pin 12 of the chip U4D is connected to capacitor C10, and pin 14 of the chip U4D outputs the reference voltage VCC3. The reference voltage circuit converts the supply voltage VCC2 into the reference voltage VCC3.

[0067] Furthermore, the LED indicator circuit includes: a resistor R10, one end of which is connected to the power supply VCC2, and the other end is connected to the positive terminal of the light-emitting diode D5. The negative terminal of the light-emitting diode is connected to pin 38 of the logic processing circuit U3. A resistor R15 is connected to the power supply VCC2, and the other end is connected to the positive terminal of the light-emitting diode D6. The negative terminal of the light-emitting diode is connected to pin 39 of the logic processing circuit U3. The LED indicator circuit is used to indicate the status of the circuit breaker and is controlled by the logic processing circuit to realize fault status indication.

[0068] To detect the zero-crossing signal of the current, the zero-crossing detection circuit includes: a resistor R29, one end of which is connected to the reference voltage VCC3 and the other end of which is connected to pin 6 of the chip U4B; a resistor R31, one end of which is connected to the current signal and the other end of which is connected to pin 5 of the chip U4B; pin 7 of the chip U4B is connected to a resistor R30; and the other end of which is connected to pin 12 of the logic processing circuit U3.

[0069] Additionally, it should be noted that the button detection circuit includes: a resistor R20, one end of which is connected to pin 39 of the logic processing circuit U3 and the other end is connected to the TVS transistor D7; a resistor R18 is connected to the power supply VCC2 and the other end is connected in series with a capacitor C7; and the touch button S1 is connected in parallel with the capacitor C7.

[0070] Furthermore, the relay control circuit includes a resistor R5 connected to the base of transistor Q5 and to pin 42 of logic processing circuit chip U3, a collector of transistor connected to resistor R1, and the other end of resistor R1 connected to the base of transistor Q1. The emitter of transistor Q1 is connected to power supply VCC1, the collector of transistor Q1 is connected to the collector of transistor Q6, the emitter of transistor Q6 is connected to the power supply ground, the base of transistor Q6 is connected to resistor R7, the other end of resistor R7 is connected to resistor R6 and connected to pin 43 of logic processing chip U3, resistor R6 is connected to the base of transistor Q4, the collector of transistor Q4 is connected to resistor R2, the other end of resistor R2 is connected to the base of transistor Q2, the emitter of transistor Q2 is connected to power supply VCC1, the collector of transistor Q2 is connected to the collector of transistor Q3, the emitter of transistor Q3 is connected to the power supply ground, resistor R8 is connected to the base of transistor Q3, connector P1 is connected to the collectors of transistors Q1 and Q6 respectively, connector P1 is connected to the collectors of transistors Q2 and Q3 respectively. The relay control circuit controls the relay operation through the logic processing circuit.

[0071] In this embodiment, such as Figure 11 As shown, the circuit board of this invention is applied in a practical circuit breaker. When the circuit breaker is powered on, the logic processing circuit collects the zero-crossing signal pulse, counts it using an internal timer, and calculates the current grid frequency based on the timing. The calculated grid frequency is used to calculate the current and voltage sampling cycle interval by collecting 64 points per cycle. The current and voltage signals collected by the logic processing circuit are calculated to reconstruct the current current and voltage waveforms. The logic processing circuit calculates the true values ​​of the current current and voltage from the collected signals and uses these true values ​​to determine whether the circuit breaker is in an overvoltage, undervoltage, or overcurrent state, and implements protection logic based on the fault state. When tripping is required, the zero-crossing detection circuit detects the zero-crossing point and then controls the relay to trip at the current zero-crossing point, which can effectively suppress the generation of arcs and extend electrical life. The logic processing circuit collects the signal converted by the voltage sampling circuit, reconstructs the current voltage waveform from the collected data, and when closing is required, it determines the peak, trough, and zero-crossing point by reconstructing the waveform, and controls the relay to close at the voltage zero-crossing point, which can effectively reduce the inrush current. The logic processing circuit controls the status of the LED indicator circuit and the key detection circuit identifies the logic.

[0072] The button detection circuit detects the status of external buttons. When a button is pressed, it outputs a low-level signal; when the button is released, it outputs a high-level signal.

[0073] Zero-crossing detection circuit: This circuit is used to detect the zero-crossing signal of the current. When the current signal is in the positive half-cycle, it outputs a high-level signal and when the current signal is in the negative half-cycle, it outputs a low-level signal.

[0074] This LED indicator circuit is used to indicate the status of the circuit breaker. It is controlled by a logic processing circuit to achieve fault status indication.

[0075] The reference voltage circuit converts the supply voltage VCC2 into a reference voltage VCC3. The voltage VCC2 is then reduced to VCC3 by a voltage regulator circuit. The reference voltage VCC3 provides a reference voltage for the voltage and current sampling circuits. This reference voltage is added to the negative half-cycle signals acquired by the voltage and current sampling circuits, ultimately ensuring that the voltages of the secondary waveforms are all positive, allowing the logic processing circuit to correctly acquire the signals.

[0076] The voltage sampling circuit is used to convert the voltage signal into a voltage signal that can be recognized by the logic processing circuit by combining the operational amplifier with the reference voltage circuit. The provided signal is then processed by the logic processing circuit to convert the electrical signal into a digital signal.

[0077] The current sampling circuit is used to convert the current signal into a voltage signal that can be recognized by the logic processing circuit by combining the operational amplifier with the reference voltage circuit. The provided signal is then processed by the logic processing circuit to convert the electrical signal into a digital signal.

[0078] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A circuit board for an electronic miniature circuit breaker, characterized in that, The circuit board includes a circuit board body, on which a power supply circuit, a logic processing circuit, a current sampling circuit, a voltage sampling circuit, a reference voltage circuit, an LED indicator circuit, a zero-crossing detection circuit, a key detection circuit, and a relay control circuit are provided. The power supply circuit is connected to the logic processing circuit, the current sampling circuit, the voltage sampling circuit, the reference voltage circuit, the LED indicator circuit, the zero-crossing detection circuit, the key detection circuit, and the relay control circuit, respectively. The current sampling circuit, voltage sampling circuit, and zero-crossing detection circuit are connected in parallel and then connected to the logic processing circuit. The LED indicator circuit, reference voltage circuit, and key detection circuit are all connected to the logic processing circuit. The logic processing circuit is connected to the relay control circuit. The power supply circuit is used to convert the input AC mains power into smooth low-voltage DC power. This DC power VCC1 provides the driving voltage to the relay drive module. VCC1 is stepped down twice to become VCC2. VCC2 supplies power to the key detection circuit, zero-crossing detection circuit, LED indicator circuit, reference voltage circuit, voltage sampling circuit, current sampling circuit and logic processing circuit. The logic processing circuit is used to realize voltage zero-crossing logic recognition, current zero-crossing logic recognition, LED light lighting control logic, key recognition logic, main circuit current calculation, and closing / opening logic control. It can process current signals to calculate the actual current value and implement current protection logic; it can also process voltage signals to calculate the actual voltage value and implement voltage protection logic. The current sampling circuit is used to convert the current signal into a voltage signal that can be recognized by the logic processing circuit through the operational amplifier circuit. The voltage sampling circuit is used to convert the voltage signal into a voltage signal that can be recognized by the logic processing circuit through the operational amplifier circuit; The reference voltage circuit is used to convert the supply voltage VCC2 into a reference voltage VCC3; The LED indicator circuit is used to indicate the status of the circuit breaker; The zero-crossing detection circuit is used to determine the current zero-crossing signal; The key detection circuit is used to detect the action status of external keys; The relay control circuit is used to control the relay operation through a logic processing circuit. The zero-crossing detection circuit includes: a resistor R29, one end of which is connected to the reference voltage VCC3 and the other end of which is connected to pin 6 of the chip U4B; a resistor R31, one end of which is connected to the current signal and the other end of which is connected to pin 5 of the chip U4B; pin 7 of the chip U4B is connected to a resistor R30; and the other end of which is connected to pin 12 of the logic processing circuit U3.

2. The electronic miniature circuit breaker circuit board according to claim 1, characterized in that: The width of the circuit board body is 18 mm.

3. The electronic miniature circuit breaker circuit board according to claim 1, characterized in that: The power supply circuit includes: terminal J1 and terminal J2, the AC input terminal of the power supply is input from terminal J1 and J2, a varistor RV1 is connected in parallel between terminal J1 and terminal J2, the varistor RV1 is connected in parallel with resistor R3, and resistor R3 is connected in series with the AC1 terminal of the rectifier bridge. The DC+ terminal of the rectifier bridge is connected in parallel with the positive terminal of capacitor C4, the negative terminal of capacitor C4 is connected in parallel with the DC- terminal of the rectifier bridge, the positive terminal of capacitor C4 is connected to pins 7 and 8 of chip U2, pin 4 of chip U2 is connected in parallel with the positive terminal of capacitor C5 and in series with diode D3, the anode of diode D3 is connected in parallel with inductor L1 and in parallel with the positive terminal of capacitor C3, the negative terminal of capacitor C3 is connected in series with the anode of freewheeling diode D4, the negative terminal of diode D4 is connected in parallel with inductor L1 and in parallel with the negative terminal of capacitor C5, the negative terminal of capacitor C5 is connected to pins 1 and 2 of chip U2, the anode of diode D1 is connected to resistor R4, diode D1 is connected in parallel with the positive terminal of capacitor C1 and is connected to pin 3 of chip U1, pin 2 of chip U1 is connected to the negative terminal of capacitor C1, and pin 1 of chip U1 is connected to capacitor C2.

4. The electronic miniature circuit breaker circuit board according to claim 1, characterized in that: The logic processing circuit uses a domestically produced MCU, U3, as the main chip.

5. The electronic miniature circuit breaker circuit board according to claim 1, characterized in that: The current sampling circuit includes: terminal P2, through which the current transformer signal is input; terminal P2 is connected in series with resistor R13, through which the secondary current of the transformer is converted into voltage; resistor R13 is connected in parallel with resistors R11 and R14 and then connected to pins 9 and 10 of chip U4C; resistor R16 is connected in parallel with resistor R14 and pin 10 of chip U4C; resistor R9 is connected in parallel with capacitor C6 and then connected to pin 8 of chip U4C and connected in series with resistor R12; the other end of resistor R12 is connected to pin 10 of logic processing circuit U3.

6. The electronic miniature circuit breaker circuit board according to claim 1, characterized in that: The voltage sampling circuit includes: terminal P3, through which the voltage signal is input; one of the two pins of terminal P3 is connected to resistor R21 and the other to resistor R24; resistor R21 is connected in series with resistor R22; resistor R24 ​​is connected in series with resistor R25; one end of resistor R26 is connected to the reference voltage VCC3 and the other end is connected to pin 3 of chip U4A; one end of resistor R19 is connected to resistor R22 and pin 1 of chip U4A; resistor R23 is connected to pin 1 of chip U4A and the other end is connected to pin 11 of logic processing circuit U3.

7. The electronic miniature circuit breaker circuit board according to claim 1, characterized in that: The reference voltage circuit includes a resistor R28, one end of which is connected to the supply voltage VCC2, and the other end is connected to the cathode of the voltage regulator Q7. Capacitors C9 and C10 are connected in parallel with the voltage regulator Q7. Pin 12 of the chip U4D is connected to capacitor C10, and pin 14 of the chip U4D outputs the reference voltage VCC3.

8. The electronic miniature circuit breaker circuit board according to claim 1, characterized in that: The LED indicator circuit includes: a resistor R10, one end of which is connected to the power supply VCC2, and the other end is connected to the positive terminal of the light-emitting diode D5. The negative terminal of the light-emitting diode is connected to pin 38 of the logic processing circuit U3. A resistor R15 is connected to the power supply VCC2, and the other end is connected to the positive terminal of the light-emitting diode D6. The negative terminal of the light-emitting diode is connected to pin 39 of the logic processing circuit U3.

9. The electronic miniature circuit breaker circuit board according to claim 1, characterized in that, The relay control circuit includes a resistor R5 connected to the base of transistor Q5 and pin 42 of logic processing chip U3; the collector of transistor Q5 is connected to resistor R1; and the other end of resistor R1 is connected to the base of transistor Q1. The emitter of transistor Q1 is connected to power supply VCC1. The collector of transistor Q1 is connected to the collector of transistor Q6. The emitter of transistor Q6 is connected to the power supply ground. The base of transistor Q6 is connected to resistor R7. The other end of resistor R7 is connected to resistor R6 and pin 43 of logic processing chip U3. Resistor R6 is connected to the base of transistor Q4. The collector of transistor Q4 is connected to resistor R2. The other end of resistor R2 is connected to the base of transistor Q2. The emitter of transistor Q2 is connected to power supply VCC1. The collector of transistor Q2 is connected to the collector of transistor Q3. The emitter of transistor Q3 is connected to the power supply ground. Resistor R8 is connected to the base of transistor Q3. Connector P1 is connected to the collectors of transistors Q1 and Q6 respectively. Connector P1 is connected to the collectors of transistors Q2 and Q3 respectively.

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