Circuit board of electronic miniature circuit breaker

Abstract

The invention discloses an electronic miniature circuit breaker circuit board which comprises a circuit board body, and the circuit board body is provided with a power circuit, a logic processing circuit, a current sampling circuit, a voltage sampling circuit, a reference voltage circuit, an LED lamp indicating circuit, a zero cross detection band circuit, a key detection circuit and a relay control circuit. The power supply circuit is respectively connected with the logic processing circuit, the current sampling circuit, the voltage sampling circuit, the reference voltage circuit, the LED lamp indicating circuit, the zero cross detection band circuit, the key detection circuit and the relay control circuit. Compared with the prior art, the circuit board has the instantaneous and current overload performance of a traditional circuit breaker, the problem that an existing overvoltage and undervoltage protector lacks current protection can be solved, electronic control is added in the closing process of the circuit breaker, the circuit breaker can actively monitor the voltage waveform, closing is conducted when the voltage crosses the zero point, and the protection effect is good. Surge current caused when a traditional circuit breaker is switched on is greatly reduced, and the risk of equipment damage is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of low-voltage electrical appliances, and in particular to a circuit board of an electronic miniature circuit breaker. Background Art

[0002] Existing over- and under-voltage circuit breakers provide over-current protection, which mainly determines whether a load at the lower port of the circuit breaker fails.

[0003] Traditional thermal-magnetic protection circuit breakers do not have the function of voltage monitoring. Voltage monitoring is the monitoring of the voltage of the power supply network. When the power grid is overvoltage or undervoltage, it can disconnect in time to protect the load. Traditional circuit breakers cannot identify voltage waveform signals when closing, and cannot guarantee closing when the voltage passes through zero, and cannot guarantee opening when the current passes through zero when opening. In addition, the mechanical life is tens of thousands of times, which is not suitable for scenarios where frequent opening and closing is performed. When opening and closing with load, the electrical life is not nearly the same, ranging from thousands to tens of thousands of times, and the life is short, which is not suitable for places where frequent opening and closing is performed with load.

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

[0005] The object of the present invention is to provide an electronic miniature circuit breaker circuit board to solve the above-mentioned problems existing in the prior art.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows: An electronic small circuit breaker circuit board comprises 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 light indication circuit, a zero-crossing detection band circuit, a key detection circuit and a relay control circuit are arranged, and the power supply circuit is respectively connected to the logic processing circuit, the current sampling circuit, the voltage sampling circuit, the reference voltage circuit, the LED light indication circuit, the zero-crossing detection band circuit, the key detection circuit and the relay control circuit; The current sampling circuit, the voltage sampling circuit and the zero-crossing detection circuit are connected in parallel to the logic processing circuit, the LED light indication circuit, the reference voltage circuit and the key detection circuit are all connected to the logic processing circuit, and the logic processing circuit is connected to the relay control circuit. The power supply circuit is used to convert the input AC mains into smooth low-voltage DC power. This DC power VCC1 provides driving voltage to the relay drive module. VCC1 is reduced twice to become VCC2. VCC2 supplies power to the key detection circuit, zero-crossing detection circuit, LED light indication 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 lamp lighting control logic, button recognition logic, main circuit current calculation, closing and opening logic control; realize current signal processing to calculate the real current value and realize current protection logic; realize voltage signal processing to calculate the real voltage value and realize 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 light indication circuit is used to indicate the circuit breaker status; The zero-crossing detection circuit is used to determine the current zero-crossing signal; The key detection circuit is used to detect the external key action state; The relay control circuit is used to control the action of the relay through the logic processing circuit.

[0007] Furthermore, the width of the circuit board body is 18MM.

[0008] Further, the power supply circuit includes: a terminal J1 and a terminal J2, the AC input end of the power supply is input from the terminals J1 and J2, a varistor RV1 is connected in parallel between the terminal J1 and the terminal J2, the varistor RV1 is connected in parallel with the resistor R3, and the resistor R3 is connected in series with the AC1 end of the rectifier bridge; The DC+ end of the rectifier bridge is connected in parallel with the positive electrode of capacitor C4, the negative electrode of capacitor C4 is connected in parallel with the DC- end of the rectifier bridge, the positive electrode 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 electrode 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 electrode of capacitor C3, the negative electrode of capacitor C3 is connected in series with the anode of freewheeling diode D4, the negative electrode of diode D4 is connected in parallel with inductor L1 and in parallel with the negative electrode of capacitor C5, the negative electrode of capacitor C5 is connected to pins 1 and 2 of chip U2, the anode of diode D1 is connected to resistor R4, the diode D1 is connected in parallel with the positive electrode of capacitor C1 and connected to pin 3 of chip U1, pin 2 of chip U1 is connected to the negative electrode of capacitor C1, and pin 1 of chip U1 is connected to capacitor C2.

[0009] Furthermore, the logic processing circuit adopts a domestically produced MCU as the main chip U3.

[0010] Further, the current sampling circuit includes: terminal P2, the current transformer signal is connected from terminal P2, terminal P2 is connected in series with resistor R13, the transformer secondary current is converted into voltage through resistor R13, resistor R13 is connected in parallel with resistors R11 and R14 respectively and then connected to pins 9 and 10 of chip U4C, resistor R16 is connected to 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, and the other end of resistor R12 is connected to pin 10 of logic processing circuit U3.

[0011] Further, the voltage sampling circuit includes: a terminal P3, a voltage signal is connected through the terminal P3, two pins of the terminal P3 are respectively connected to resistors R21 and R24, the resistor R21 is connected in series with the resistor R22, the resistor R24 ​​is connected in series with the resistor R25, one end of the resistor R26 is connected to the reference voltage VCC3 and the other end is connected to the resistor R26 and the 3rd pin of the chip U4A, one end of the resistor R19 is connected to the resistor R22 and the 1st pin of the chip U4A, the resistor R23 is connected to the 1st pin of the chip U4A and the other end is connected to the 11th pin of the logic processing circuit U3.

[0012] Furthermore, the reference voltage circuit includes a resistor R28, one end of the resistor R28 is connected to the power supply voltage VCC2, and the other end is connected to the cathode of the voltage regulator Q7, capacitor C9 and capacitor C10 are connected in parallel with the voltage regulator Q7, pin 12 of chip U4D is connected to capacitor C10, and pin 14 of chip U4D outputs the reference voltage VCC3.

[0013] Furthermore, the LED light indication 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 electrode of the light-emitting diode D5, and the negative electrode of the light-emitting diode is connected to the pin 38 of the logic processing circuit U3; one end of the resistor R15 is connected to the power supply VCC2, and the other end is connected to the positive electrode of the light-emitting diode D6, and the negative electrode of the light-emitting diode is connected to the pin 39 of the logic processing circuit U3.

[0014] Further, the zero-crossing detection circuit includes: a resistor R29, one end of the resistor R29 is connected to the reference voltage VCC3, and the other end is connected to the 6th pin of the chip U4B, one end of the resistor R31 is connected to the current signal, and the other end is connected to the 5th pin of the chip U4B, the 7th pin of the chip U4B is connected to the resistor R30, and the other end is connected to the 12th pin of the logic processing circuit U3.

[0015] Furthermore, the key detection circuit includes: a resistor R20, one end of the resistor R20 is connected to the 39 pin of the logic processing circuit U3 and the other end is connected to the TVS tube D7, the resistor R18 is connected to the power supply VCC2 and the other end is connected in series with the capacitor C7, and the touch button S1 is connected in parallel with the capacitor C7.

[0016] Furthermore, the relay control circuit includes a resistor R5 connected to the base of the transistor Q5 and to the pin 42 of the logic processing circuit chip U3, the transistor collector is connected to the resistor R1, and the other end of the resistor R1 is connected to the base of the transistor Q1. The emitter of transistor Q1 is connected to the 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 loop ground, the base of transistor Q6 is connected to resistor R7, the other end of resistor R7 is connected to resistor R6 and is connected to pin 43 of the logic processing circuit 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 the 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 loop ground, resistor R8 is connected to the base of transistor Q3, the connector P1 is respectively connected to the collector of transistor Q1 and the collector of transistor Q6, and the connector P1 is respectively connected to the collector of transistor Q2 and the collector of transistor Q3.

[0017] The beneficial effects of the present invention are: The electronic miniature circuit breaker circuit board of the present invention adds electronic control during the circuit breaker opening process, thereby being able to monitor the main circuit current and open the circuit when the current passes through zero, effectively suppressing the generation of arcs. The opening and closing uses a magnetic latching relay, and the mechanical life of the relay can reach 200,000 times, so that the product can work in scenarios where frequent opening and closing are required; By adding electronic control to the circuit breaker closing process, the circuit breaker can actively monitor the voltage waveform and close when the voltage passes through zero, which greatly reduces the surge current caused by closing traditional circuit breakers and reduces the risk of equipment damage. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a diagram showing the composition of a circuit board module of an electronic miniature circuit breaker of the present invention; Figure 2 is a circuit diagram of a power supply circuit of the present invention; Figure 3 is a circuit diagram of a logic processing circuit of the present invention; Figure 4 is a circuit diagram of a current sampling circuit of the present invention; Figure 5 is a circuit diagram of a voltage sampling circuit of the present invention; Figure 6is a circuit diagram of a reference voltage circuit of the present invention; Figure 7 It is a circuit diagram of the LED lamp indication of the present invention; Figure 8 is a circuit diagram of a zero-crossing detection circuit of the present invention; Fig. 9 is a circuit diagram of a key detection circuit of the present invention; Fig.10 is a circuit diagram of a relay control circuit of the present invention; Fig.11 It is a working flow chart of the electronic miniature circuit breaker of the present invention. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation methods described herein are only used to explain the present invention and are not used to limit the present invention.

[0020] Among them, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention or simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0021] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0022] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0023] In addition, in order to better illustrate the present application, numerous specific details are given in the following specific embodiments. It should be understood by those skilled in the art that the present application can also be implemented without certain specific details. In some examples, methods, means, components and circuits well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present application.

[0024] like Figures 1 to 10 As shown, the present invention relates to an electronic miniature circuit breaker circuit board, comprising 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 light indication circuit, a zero-crossing detection band circuit, a key detection circuit and a relay control circuit are arranged, and the power supply circuit is respectively connected to the logic processing circuit, the current sampling circuit, the voltage sampling circuit, the reference voltage circuit, the LED light indication circuit, the zero-crossing detection band circuit, the key detection circuit and the relay control circuit; The current sampling circuit, the voltage sampling circuit and the zero-crossing detection circuit are connected in parallel to the logic processing circuit, the LED light indication circuit, the reference voltage circuit and the key detection circuit are all connected to the logic processing circuit, and the logic processing circuit is connected to the relay control circuit. The power supply circuit is used to convert the input AC mains into smooth low-voltage DC power. This DC power VCC1 provides driving voltage to the relay drive module. VCC1 is reduced twice to become VCC2. VCC2 supplies power to the key detection circuit, zero-crossing detection circuit, LED light indication 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 lamp lighting control logic, button recognition logic, main circuit current calculation, closing and opening logic control; realize current signal processing to calculate the real current value and realize current protection logic; realize voltage signal processing to calculate the real voltage value and realize 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 light indication circuit is used to indicate the circuit breaker status; The zero-crossing detection circuit is used to determine the current zero-crossing signal; The key detection circuit is used to detect the external key action state; The relay control circuit is used to control the action of the relay through the logic processing circuit.

[0025] Through the above method, it can be known that the over-voltage and under-voltage protection can not only replace the over-voltage and under-voltage protection devices on the market, but also has voltage zero-crossing closing and current zero-crossing segmentation, which is particularly suitable for places where the switch is frequently opened and closed. Unlike traditional circuit breakers, the present invention uses relays as the main carrier for connecting and disconnecting the main circuit, and has the characteristics of electronic control. Adding current detection can well restore the thermal magnetic protection of traditional circuit breakers, so the present invention can not only replace traditional circuit breakers, but also play a good role in reducing the impact on the load.

[0026] In this embodiment, the width of the circuit board body is set to 18MM, which greatly saves the space of the distribution box.

[0027] Specifically, the power supply circuit includes: a terminal J1 and a terminal J2, the AC input end of the power supply is input from the terminals J1 and J2, a varistor RV1 is connected in parallel between the terminal J1 and the terminal J2, the varistor RV1 is connected in parallel with a resistor R3, and the resistor R3 is connected in series with the AC1 end of the rectifier bridge; The DC+ end of the rectifier bridge is connected in parallel with the positive electrode of capacitor C4, the negative electrode of capacitor C4 is connected in parallel with the DC- end of the rectifier bridge, the positive electrode 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 electrode 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 electrode of capacitor C3, the negative electrode of capacitor C3 is connected in series with the anode of freewheeling diode D4, the negative electrode of diode D4 is connected in parallel with inductor L1 and in parallel with the negative electrode of capacitor C5, the negative electrode of capacitor C5 is connected to pins 1 and 2 of chip U2, the anode of diode D1 is connected to resistor R4, the diode D1 is connected in parallel with the positive electrode of capacitor C1 and connected to pin 3 of chip U1, pin 2 of chip U1 is connected to the negative electrode 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, and this DC power VCC1 provides driving voltage to the relay drive module. VCC1 is stepped down twice to become VCC2, and VCC2 supplies power to the key detection circuit, zero-crossing detection circuit, LED light indication circuit, reference voltage circuit, voltage sampling circuit, current sampling circuit, and logic processing circuit.

[0028] In this embodiment, the logic processing circuit uses a domestic MCU as the main chip U3, which is used to realize voltage zero-crossing logic recognition, current zero-crossing logic recognition, LED light lighting control logic, button recognition logic, main circuit current calculation, and closing and opening logic control. The current signal is processed to calculate the real current value and realize the current protection logic. The voltage signal is processed to calculate the real voltage value and realize the voltage protection logic; Further, the current sampling circuit includes: terminal P2, the current transformer signal is connected from terminal P2, terminal P2 is connected in series with resistor R13, the transformer secondary current is converted into voltage through resistor R13, resistor R13 is connected in parallel with resistors R11 and R14 respectively and then connected to pins 9 and 10 of chip U4C, resistor R16 is connected to 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, and 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.

[0029] It is also worth noting that the voltage sampling circuit includes: terminal P3, the voltage signal is connected through terminal P3, the two pins of terminal P3 are respectively connected to resistors R21 and 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 reference voltage VCC3 and the other end is connected to resistor R26 and 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 can be recognized by the logic processing circuit through an operational amplifier circuit, that is, converts the voltage signal into a voltage signal that can be recognized by the logic processing circuit through an operational amplifier circuit.

[0030] In addition, the present embodiment also includes a reference voltage circuit, which includes a resistor R28, one end of the resistor R28 is connected to the power supply voltage VCC2, and the other end is connected to the cathode of the voltage regulator Q7, capacitor C9 and capacitor C10 are connected in parallel with the voltage regulator Q7, pin 12 of chip U4D is connected to capacitor C10, and pin 14 of chip U4D outputs a reference voltage VCC3. The reference voltage circuit converts the power supply voltage VCC2 into a reference voltage VCC3.

[0031] Furthermore, the LED light indication circuit includes: a resistor R10, one end of the resistor R10 is connected to the power supply VCC2, and the other end is connected to the positive electrode of the light-emitting diode D5, and the negative electrode of the light-emitting diode is connected to the 38th pin of the logic processing circuit U3; one end of the resistor R15 is connected to the power supply VCC2, and the other end is connected to the positive electrode of the light-emitting diode D6, and the negative electrode of the light-emitting diode is connected to the 39th pin of the logic processing circuit U3. The LED light indication circuit is used to indicate the state of the circuit breaker, and is controlled by the logic processing circuit to realize the fault state indication.

[0032] In order to distinguish the current zero-crossing signal, the zero-crossing detection circuit includes: a resistor R29, one end of the resistor R29 is connected to the reference voltage VCC3, and the other end is connected to the 6th pin of the chip U4B, one end of the resistor R31 is connected to the current signal, and the other end is connected to the 5th pin of the chip U4B, the 7th pin of the chip U4B is connected to the resistor R30, and the other end is connected to the 12th pin of the logic processing circuit U3.

[0033] In addition, it should be noted that the key detection circuit includes: a resistor R20, one end of the resistor R20 is connected to the 39 pin of the logic processing circuit U3 and the other end is connected to the TVS tube D7, a resistor R18 is connected to the power supply VCC2 and the other end is connected in series with the capacitor C7, and the touch button S1 is connected in parallel with the capacitor C7.

[0034] Furthermore, the relay control circuit includes a resistor R5 connected to the base of the transistor Q5 and to the pin 42 of the logic processing circuit chip U3, the transistor collector is connected to the resistor R1, and the other end of the resistor R1 is connected to the base of the transistor Q1. The emitter of transistor Q1 is connected to the 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 loop ground, the base of transistor Q6 is connected to resistor R7, the other end of resistor R7 is connected to resistor R6 and is connected to pin 43 of the logic processing circuit 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 the 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 loop ground, resistor R8 is connected to the base of transistor Q3, the connector P1 is respectively connected to the collector of transistor Q1 and the collector of transistor Q6, the connector P1 is respectively connected to the collector of transistor Q2 and the collector of transistor Q3, and the relay control circuit controls the relay action through the logic processing circuit.

[0035] In this embodiment, if Fig.11As shown, the application of the circuit board of the present invention in the actual circuit breaker, when the circuit breaker is powered on, the logic processing circuit collects the zero-crossing signal pulse, and the internal timer is used to calculate the current power grid frequency through the timing time. The calculated power grid frequency collects 64 points in each cycle to calculate the current and voltage collection cycle interval. The current signal and voltage signal collected by the logic processing circuit are calculated to restore the current current and voltage waveforms. The logic processing circuit calculates the collected signals to obtain the current current and voltage true values, and judges whether the current circuit breaker is in overvoltage, undervoltage, or overcurrent state through the calculated true values, and implements the protection logic according to the fault state. When it is necessary to open the gate, the zero-crossing point is detected by the zero-crossing detection circuit, and then the relay is controlled to open the gate at the current zero-crossing point, which can effectively suppress the generation of arcs and extend the electrical life. The logic processing circuit collects the signal converted by the voltage sampling circuit, restores the current voltage waveform by collecting data, and when it is necessary to close the gate, the peak, trough and zero-crossing point are judged by restoring the waveform, and the relay is controlled to close the gate when the voltage crosses the zero point, which can effectively reduce the power-on surge current. The logic processing circuit controls the LED light to indicate the circuit status and the key detection circuit to identify the logic.

[0036] Key detection circuit: This circuit detects the action status of external keys. When the key is pressed, it outputs a low-level signal, and when the key is released, it outputs a high-level signal.

[0037] Zero-crossing detection circuit: The function of this circuit is to judge the current zero-crossing signal. When the collected 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.

[0038] LED light indication circuit, this circuit is used to indicate the circuit breaker status. It is controlled by the logic processing circuit to realize the fault status indication; The function of the reference voltage circuit is to convert the power supply voltage VCC2 into the reference voltage VCC3. The VCC2 voltage is reduced to VCC3 through the voltage regulator circuit. The reference voltage VCC3 provides a reference voltage for the voltage sampling circuit and the current sampling circuit. The reference voltage is added to the negative half-cycle signal collected by the voltage sampling circuit and the current sampling circuit, and finally the voltage of the secondary waveform is positive, so that the logic processing circuit can collect it correctly.

[0039] Voltage sampling circuit: The function of this circuit is to convert the secondary voltage signal into a voltage signal that can be recognized by the logic processing circuit by combining the voltage signal with the reference voltage circuit through an operational amplifier. The provided signal is converted into a digital signal for processing by the logic processing circuit.

[0040] Current sampling circuit: This circuit is used to convert the secondary voltage signal into a voltage signal that can be recognized by the logic processing circuit by combining the current signal with the reference voltage circuit through an operational amplifier. The provided signal is converted into a digital signal for processing through the logic processing circuit.

[0041] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be considered as the scope of protection of the present invention.

Claims

1. An electronic miniature circuit breaker circuit board, characterized in that: It 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 light indication circuit, a zero-crossing detection band circuit, a key detection circuit and a relay control circuit are arranged, and the power supply circuit is respectively connected to the logic processing circuit, the current sampling circuit, the voltage sampling circuit, the reference voltage circuit, the LED light indication circuit, the zero-crossing detection band circuit, the key detection circuit and the relay control circuit; The current sampling circuit, the voltage sampling circuit and the zero-crossing detection circuit are connected in parallel to the logic processing circuit, the LED light indication circuit, the reference voltage circuit and the key detection circuit are all connected to the logic processing circuit, and the logic processing circuit is connected to the relay control circuit. The power supply circuit is used to convert the input AC mains into smooth low-voltage DC power. This DC power VCC1 provides driving voltage to the relay drive module. VCC1 is reduced twice to become VCC2. VCC2 supplies power to the key detection circuit, zero-crossing detection circuit, LED light indication 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 lamp lighting control logic, button recognition logic, main circuit current calculation, and closing and opening logic control; The current signal is processed to calculate the real current value and realize the current protection logic; the voltage signal is processed to calculate the real voltage value and realize the 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 light indication circuit is used to indicate the circuit breaker status; The zero-crossing detection circuit is used to determine the current zero-crossing signal; The key detection circuit is used to detect the external key action state; The relay control circuit is used to control the action of the relay through a logic processing circuit.

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

3. The electronic miniature circuit breaker circuit board according to claim 1, characterized in that: The power supply circuit includes: a terminal J1 and a terminal J2, the AC input end of the power supply is input from the terminals J1 and J2, a varistor RV1 is connected in parallel between the terminals J1 and J2, the varistor RV1 is connected in parallel with a resistor R3, and the resistor R3 is connected in series with the AC1 end of the rectifier bridge; The DC+ end of the rectifier bridge is connected in parallel with the positive electrode of capacitor C4, the negative electrode of capacitor C4 is connected in parallel with the DC- end of the rectifier bridge, the positive electrode 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 electrode 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 electrode of capacitor C3, the negative electrode of capacitor C3 is connected in series with the anode of freewheeling diode D4, the negative electrode of diode D4 is connected in parallel with inductor L1 and in parallel with the negative electrode of capacitor C5, the negative electrode of capacitor C5 is connected to pins 1 and 2 of chip U2, the anode of diode D1 is connected to resistor R4, the diode D1 is connected in parallel with the positive electrode of capacitor C1 and connected to pin 3 of chip U1, pin 2 of chip U1 is connected to the negative electrode 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 adopts a domestically produced MCU as the main chip U3.

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

6. The contactor DC holding energy-saving control circuit according to claim 1, characterized in that: The voltage sampling circuit includes: a terminal P3, a voltage signal is connected through the terminal P3, two pins of the terminal P3 are respectively connected to resistors R21 and R24, the resistor R21 is connected in series with the resistor R22, the resistor R24 ​​is connected in series with the resistor R25, one end of the resistor R26 is connected to the reference voltage VCC3, and the other end is connected to the resistor R26 and the 3rd pin of the chip U4A, one end of the resistor R19 is connected to the resistor R22 and the 1st pin of the chip U4A, and the resistor R23 is connected to the 1st pin of the chip U4A and the other end is connected to the 11th pin of the logic processing circuit U3.

7. The contactor DC holding energy-saving control circuit according to claim 1, characterized in that: The reference voltage circuit includes a resistor R28, one end of which is connected to the power 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 chip U4D is connected to capacitor C10, and pin 14 of chip U4D outputs the reference voltage VCC3.

8. The contactor DC holding energy-saving control circuit according to claim 1, characterized in that: The LED light indication circuit includes: a resistor R10, one end of the resistor R10 is connected to the power supply VCC2, and the other end is connected to the positive electrode of the light-emitting diode D5, and the negative electrode of the light-emitting diode is connected to the 38th pin of the logic processing circuit U3; one end of the resistor R15 is connected to the power supply VCC2, and the other end is connected to the positive electrode of the light-emitting diode D6, and the negative electrode of the light-emitting diode is connected to the 39th pin of the logic processing circuit U3.

9. The contactor DC holding energy-saving control circuit according to claim 1, characterized in that: The zero-crossing detection circuit includes: a resistor R29, one end of the resistor R29 is connected to the reference voltage VCC3, and the other end is connected to the 6th pin of the chip U4B, one end of the resistor R31 is connected to the current signal, and the other end is connected to the 5th pin of the chip U4B, the 7th pin of the chip U4B is connected to the resistor R30, and the other end is connected to the 12th pin of the logic processing circuit U3.

10. The contactor DC holding energy-saving control circuit according to claim 1, characterized in that: The relay control circuit includes a resistor R5 connected to the base of the transistor Q5 and connected to the 42nd pin of the logic processing circuit chip U3, a transistor collector connected to the resistor R1, and the other end of the resistor R1 connected to the base of the transistor Q1. 1 emitter is connected to the 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 loop 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 the logic processing circuit 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 the 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 loop ground, resistor R8 is connected to the base of transistor Q3, the connector P1 is respectively connected to the collector of transistor Q1 and the collector of transistor Q6, and the connector P1 is respectively connected to the collector of transistor Q2 and the collector of transistor Q3.

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