Safety protection circuit for low voltage circuit breaker

Abstract

The application discloses a kind of safety protection low-voltage circuit breaker circuits, it is related to the field of circuit breaker, the safety protection low-voltage circuit breaker circuits includes: power supply module, for supply voltage;Power-on protection module, for preventing current surge when power-on;Drive resistance reduction module, for power-on delay, reduce the resistance of power-on protection module;Current sampling output module, for sampling output current to circuit breaker detection module, and convert into voltage signal output to safety detection module;Compared with prior art, the beneficial effects of the application are: the application increases peripheral circuit on the basis of traditional circuit breaker, detects circuit condition by current sampling output module, safety detection module cooperates, and circuit breaker detection module controls the on-off of on-off control output module together, prevents circuit failure from causing load damage when circuit breaker fails;Power-on protection module and drive resistance reduction module cooperate, effectively prevent the large current generated in power-on moment from causing circuit to disconnect.

Description

Technical Field

[0001] This invention relates to the field of circuit breakers, specifically a safety protection low-voltage circuit breaker circuit. Background Technology

[0002] A low-voltage circuit breaker is a switching device that connects and disconnects short-circuit currents. Besides its control function, a low-voltage circuit breaker also provides certain protective functions, such as overload, short-circuit, undervoltage, and leakage protection. When a short circuit or a large overcurrent occurs, the electromagnetic trip unit increases its attraction, drawing the armature together and disconnecting the main contacts. If the voltage on the line drops or decreases, the undervoltage trip unit decreases its attraction or loses its attraction, and the armature is pulled away by the spring, disconnecting the main contacts.

[0003] Existing low-voltage circuit breakers have good protection measures and can disconnect the circuit in time when there is a circuit fault; however, when there is a fault in the low-voltage circuit breaker, it directly supplies abnormal voltage and current to the load, which can easily cause damage to the load and needs to be improved. Summary of the Invention

[0004] The purpose of this invention is to provide a safe and protective low-voltage circuit breaker circuit to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A safety protection low-voltage circuit breaker circuit includes:

[0007] The power supply module is used to supply voltage;

[0008] Power-on protection module, used to prevent sudden current surges when power is applied;

[0009] The drive resistance reduction module is used to reduce the resistance of the power-on protection module after the power-on delay.

[0010] The current sampling output module is used to sample the current output to the circuit breaker detection module and convert it into a voltage signal for output to the safety detection module.

[0011] The circuit breaker detection module is used to output different signals to the on / off control output module according to different conditions of the power supply module output current: normal, exceeding the upper limit threshold, or below the lower limit threshold.

[0012] The safety detection module is used to output different signals to the on / off control output module based on the voltage signal corresponding to the sampled current, which reflects the output current of the power supply module. The output current is normal, exceeds the upper limit threshold, or is below the lower limit threshold.

[0013] The on / off control output module is used to control whether to supply power to the load based on different signals output by the circuit breaker detection module and the safety detection module;

[0014] The output terminal of the power supply module is connected to the first input terminal of the power-on protection module. The output terminal of the power-on protection module is connected to the input terminal of the current sampling output module. The first output terminal of the current sampling output module is connected to the input terminal of the circuit breaker detection module and the first input terminal of the on / off control output module. The second output terminal of the current sampling output module is connected to the input terminal of the safety detection module. The first output terminal of the safety detection module is connected to the input terminal of the drive resistance reduction module. The output terminal of the drive resistance reduction module is connected to the second input terminal of the power-on protection module. The output terminal of the circuit breaker detection module is connected to the second input terminal of the on / off control output module. The second output terminal of the safety detection module is connected to the third input terminal of the on / off control output module.

[0015] As a further embodiment of the present invention: the power-on protection module includes a first resistor, a second thyristor, and a first switch. One end of the first resistor is connected to the output terminal of the power supply module and the positive terminal of the second thyristor. The other end of the first resistor is connected to the negative terminal of the second thyristor and one end of the first switch. The other end of the first switch is connected to the input terminal of the current sampling output module. The control terminal of the second thyristor is connected to the output terminal of the drive resistance reduction module.

[0016] As a further embodiment of the present invention: the driving resistance reduction module includes a seventh resistor, a second capacitor, a seventh inverter, and an eighth inverter. The input terminal of the seventh inverter is connected to one end of the seventh resistor and one end of the second capacitor. The output terminal of the seventh inverter is connected to the other end of the seventh resistor and the input terminal of the eighth inverter. The output terminal of the eighth inverter is connected to the other end of the second capacitor and the second input terminal of the power-on protection module. The power supply terminals of the seventh and eighth inverters are connected to the first output terminal of the safety detection module.

[0017] As a further embodiment of the present invention: the current sampling output module includes a current transformer and a fifth resistor. The first end of the current transformer is connected to the output end of the power-on protection module, the second end of the current transformer is connected to the input end of the circuit breaker detection module and the first input end of the on / off control output module, the third end of the current transformer is connected to one end of the fifth resistor, and the other end of the fifth resistor is connected to the fourth end of the current transformer and the input end of the safety detection module.

[0018] As a further embodiment of the present invention: the circuit breaker detection module includes a circuit breaker, the input terminal of the circuit breaker is connected to the first output terminal of the current sampling output module, and the output terminal of the circuit breaker is connected to the second input terminal of the on / off control output module.

[0019] As a further aspect of the present invention: the security detection module includes:

[0020] The upper limit threshold detection module is used to output a low level to the on / off control output module when the output current exceeds the upper limit threshold.

[0021] The lower threshold detection module is used to output a low level to the on / off control output module when the output current is lower than the lower threshold.

[0022] The upper limit threshold detection module and the lower limit threshold detection module are connected in parallel.

[0023] As a further embodiment of the present invention: the over-limit threshold detection module includes a fourth resistor, a third diode, a second amplifier, and a fourth inverter. One end of the fourth resistor is connected to the output terminal of the power-on protection module, and the other end of the fourth resistor is connected to the negative terminal of the third diode and the inverting terminal of the second amplifier. The positive terminal of the third diode is grounded. The non-inverting terminal of the second amplifier is connected to the second output terminal of the current sampling output module. The output terminal of the second amplifier is connected to the input terminal of the fourth inverter. The output terminal of the fourth inverter is connected to the third input terminal of the channel control output module.

[0024] As a further embodiment of the present invention: the lower threshold detection module includes a second resistor, a third resistor, a second diode, and a third amplifier. One end of the second resistor is connected to the output terminal of the power-on protection module, and the other end of the second resistor is connected to one end of the third resistor. The other end of the third resistor is connected to the negative terminal of the second diode, the input terminal of the drive resistance reduction module, and the inverting terminal of the third amplifier. The positive terminal of the second diode is grounded. The non-inverting terminal of the third amplifier is connected to the second output terminal of the current sampling output module, and the output terminal of the third amplifier is connected to the third input terminal of the channel control output module.

[0025] As a further embodiment of the present invention: the on / off control output module includes an AND gate, a fourth diode, a relay, a first MOSFET, a fifth diode, a first capacitor, a sixth resistor, and a first thyristor. The positive terminal of the first thyristor is connected to the first output terminal of the current sampling output module, the negative terminal of the first thyristor is connected to the load, the control terminal of the first thyristor is connected to one end of the sixth resistor, the other end of the sixth resistor is connected to one end of the first capacitor, the negative terminal of the fourth diode, one end of the relay, and the negative terminal of the fifth diode, the other end of the first capacitor is grounded, the other end of the relay is connected to the positive terminal of the fifth diode, the source terminal of the first MOSFET, the drain terminal of the first MOSFET is grounded, the gate terminal of the first MOSFET is connected to the positive terminal of the fourth diode, and the output terminal of the AND gate. One end of the input terminal of the AND gate is connected to the output terminal of the circuit breaker detection module, and the other end of the input terminal of the AND gate is connected to the second output terminal of the safety detection module.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention adds peripheral circuits to the traditional circuit breaker, and detects the circuit status through the current sampling output module and the safety detection module, and together with the circuit breaker detection module, controls the on / off control output module to prevent the circuit failure from causing load damage when the circuit breaker fails; the power-on protection module and the drive resistance reduction module work together to effectively prevent the large current generated at the moment of power-on from causing the circuit to disconnect. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of a low-voltage circuit breaker for safety protection.

[0028] Figure 2 This is a circuit diagram of a low-voltage circuit breaker circuit for safety protection.

[0029] Figure 3 The circuit diagram for driving the resistance reduction module. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0031] Please see Figure 1 A safety protection low-voltage circuit breaker circuit, comprising:

[0032] Power supply module 1 is used to supply voltage;

[0033] Power-on protection module 2 is used to prevent sudden current surges when power is applied;

[0034] Drive resistance reduction module 3, used to reduce the resistance value of power-on protection module 2 after power-on delay;

[0035] The current sampling output module 4 is used to sample the current output to the circuit breaker detection module 5 and convert it into a voltage signal for output to the safety detection module 6.

[0036] Circuit breaker detection module 5 is used to output different signals to on / off control output module 7 according to different conditions of the power supply module 1 output current: normal, exceeding the upper limit threshold, or below the lower limit threshold.

[0037] Safety detection module 6 is used to output different signals to on / off control output module 7 based on the output current of power supply module 1 as reflected by the voltage signal corresponding to the sampled current, and according to different conditions such as normal output current, exceeding the upper limit threshold, or below the lower limit threshold.

[0038] The on / off control output module 7 is used to control whether to supply power to the load based on different signals output by the circuit breaker detection module 5 and the safety detection module 6;

[0039] The output terminal of power supply module 1 is connected to the first input terminal of power-on protection module 2. The output terminal of power-on protection module 2 is connected to the input terminal of current sampling output module 4. The first output terminal of current sampling output module 4 is connected to the input terminal of circuit breaker detection module 5 and the first input terminal of on / off control output module 7. The second output terminal of current sampling output module 4 is connected to the input terminal of safety detection module 6. The first output terminal of safety detection module 6 is connected to the input terminal of drive resistance reduction module 3. The output terminal of drive resistance reduction module 3 is connected to the second input terminal of power-on protection module 2. The output terminal of circuit breaker detection module 5 is connected to the second input terminal of on / off control output module 7. The second output terminal of safety detection module 6 is connected to the third input terminal of on / off control output module 7.

[0040] In this embodiment: Please refer to Figure 2 The power-on protection module 2 includes a first resistor R1, a second thyristor Z2, and a first switch S1. One end of the first resistor R1 is connected to the output terminal of the power supply module 1 and the positive terminal of the second thyristor Z2. The other end of the first resistor R1 is connected to the negative terminal of the second thyristor Z2 and one end of the first switch S1. The other end of the first switch S1 is connected to the input terminal of the current sampling output module 4. The control terminal of the second thyristor Z2 is connected to the output terminal of the drive resistance reduction module 3.

[0041] At the moment of power-on, a large current will be generated. At this time, since there is no signal input at the control electrode of the second thyristor Z2, the second thyristor Z2 is cut off, and the large current supplies power to the subsequent circuit through the first resistor R1.

[0042] In another embodiment, the second thyristor Z2 can be replaced by a MOSFET, but the disadvantage is that the voltage consumed by the MOSFET after it is turned on is greater than that of the second thyristor Z2.

[0043] In this embodiment: Please refer to Figure 3 The drive resistance reduction module 3 includes a seventh resistor R7, a second capacitor C2, a seventh inverter U7, and an eighth inverter U8. The input terminal of the seventh inverter U7 is connected to one end of the seventh resistor R7 and one end of the second capacitor C2. The output terminal of the seventh inverter U7 is connected to the other end of the seventh resistor R7 and the input terminal of the eighth inverter U8. The output terminal of the eighth inverter U8 is connected to the other end of the second capacitor C2 and the second input terminal of the power-on protection module 2. The power supply terminals of the seventh inverter U7 and the eighth inverter U8 are connected to the first output terminal of the safety detection module 6.

[0044] Initially, the input of the seventh inverter U7 is low and the output is high, while the output of the eighth inverter U8 is low. The output of the seventh inverter U7 charges the second capacitor C2 through the seventh resistor R7. As the second capacitor C2 charges, the input of the seventh inverter U7 becomes high and the output becomes low, while the output of the eighth inverter U8 becomes high (the time it takes for the eighth inverter U8 to first go from low to high is the delay time). At this time, the second capacitor C2 discharges through the seventh resistor R7, becoming low again. This process repeats, causing the eighth inverter U8 to output a PWM signal. When the circuit starts running, a large instantaneous current is supplied through the first resistor R1. After a delay (the delay time is longer than the instantaneous large current time), the second thyristor Z2 turns on, causing the overall impedance of the power-on protection module 2 to decrease. This reduces the voltage loss of the power supply module 1 through the power-on protection module 2, supplying power to the subsequent circuits.

[0045] In another embodiment: the seventh resistor R7 can be replaced with a potentiometer to adjust the delay time. Since the instantaneous high current time is short and the delay time requirement is not strict, a regular resistor can be used.

[0046] In this embodiment: Please refer to Figure 2 The current sampling output module 4 includes a current transformer U1 and a fifth resistor R5. The first end of the current transformer U1 is connected to the output end of the power-on protection module 2. The second end of the current transformer U1 is connected to the input end of the circuit breaker detection module 5 and the first input end of the on / off control output module 7. The third end of the current transformer U1 is connected to one end of the fifth resistor R5. The other end of the fifth resistor R5 is connected to the fourth end of the current transformer U1 and the input end of the safety detection module 6.

[0047] There is no significant voltage drop between the first and second terminals of the current transformer U1 (the coil is between the first and second terminals of the current transformer U1, and the coil is between the third and fourth terminals, so the loss is low), which allows the output voltage from the power supply module 1 to maintain a high voltage and current output even after passing through the power-on protection module 2 and the current sampling output module 4, resulting in low circuit loss; the sampling output current from the third and fourth terminals of the current transformer U1 flows through the fifth resistor R5 and becomes a sampling voltage, which is then output to the circuit breaker detection module 5.

[0048] In another embodiment, the sampling voltage can be amplified by adding devices such as amplifiers.

[0049] In this embodiment: Please refer to Figure 2 The circuit breaker detection module 5 includes a circuit breaker U5. The input terminal of the circuit breaker U5 is connected to the first output terminal of the current sampling output module 4, and the output terminal of the circuit breaker U5 is connected to the second input terminal of the on / off control output module 7.

[0050] Circuit breaker U5 achieves circuit breaking protection by allowing current to flow through it. Excessive or insufficient current will alter the magnetic tripping force of the electromagnetic trip unit, causing circuit breaker U5 to disconnect the power supply. Circuit breaker U5 is existing technology and will not be described in detail here.

[0051] In this embodiment: Please refer to Figure 2 The security detection module 6 includes:

[0052] The upper limit threshold detection module is used to output a low level to the on / off control output module 7 when the output current exceeds the upper limit threshold.

[0053] The lower threshold detection module is used to output a low level to the on / off control output module 7 when the output current is lower than the lower threshold.

[0054] The upper limit threshold detection module and the lower limit threshold detection module are connected in parallel.

[0055] In this embodiment: Please refer to Figure 2 The threshold detection module includes a fourth resistor R4, a third diode D3, a second amplifier U2, and a fourth inverter U4. One end of the fourth resistor R4 is connected to the output terminal of the power-on protection module 2, and the other end of the fourth resistor R4 is connected to the negative terminal of the third diode D3 and the inverting terminal of the second amplifier U2. The positive terminal of the third diode D3 is grounded. The non-inverting terminal of the second amplifier U2 is connected to the second output terminal of the current sampling output module 4. The output terminal of the second amplifier U2 is connected to the input terminal of the fourth inverter U4. The output terminal of the fourth inverter U4 is connected to the third input terminal of the channel control output module.

[0056] When the output current of power supply module 1 is too large, the sampling voltage of current sampling output module 4 is large, which makes the voltage at the non-inverting terminal of the second amplifier U2 higher than the voltage at the inverting terminal (the third diode D3 is a Zener diode). This causes the second amplifier U2 to output a high level, which is then output as a low level after passing through the fourth inverter U4.

[0057] In another embodiment, a light-emitting diode (LED) can be added to indicate the current operating status of the device.

[0058] In this embodiment: Please refer to Figure 2The lower threshold detection module includes a second resistor R2, a third resistor R3, a second diode D2, and a third amplifier U3. One end of the second resistor R2 is connected to the output terminal of the power-on protection module 2, and the other end of the second resistor R2 is connected to one end of the third resistor R3. The other end of the third resistor R3 is connected to the negative terminal of the second diode D2, the input terminal of the drive resistance reduction module 3, and the inverting terminal of the third amplifier U3. The positive terminal of the second diode D2 is grounded. The non-inverting terminal of the third amplifier U3 is connected to the second output terminal of the current sampling output module 4, and the output terminal of the third amplifier U3 is connected to the third input terminal of the channel control output module.

[0059] When the output current of power supply module 1 is too small, the sampling voltage of current sampling output module 4 is small, which makes the voltage at the non-inverting terminal of the third amplifier U3 lower than the voltage at the inverting terminal (the second diode D2 is a Zener diode), causing the third amplifier U3 to output a low level.

[0060] In another embodiment: the voltage on the second diode D2 is sampled here to power the drive resistance reduction module 3. Other methods can also be used to power the drive resistance reduction module 3. The safety detection module 6 is similar to the drive resistance reduction module 3, which makes subsequent circuit wiring convenient.

[0061] In this embodiment: Please refer to Figure 2 The on / off control output module 7 includes an AND gate U6, a fourth diode D4, a relay J1, a first MOSFET V1, a fifth diode D5, a first capacitor C1, a sixth resistor R6, and a first thyristor Z1. The positive terminal of the first thyristor Z1 is connected to the first output terminal of the current sampling output module 4, and the negative terminal of the first thyristor Z1 is connected to the load. The control terminal of the first thyristor Z1 is connected to one end of the sixth resistor R6. The other end of the sixth resistor R6 is connected to one end of the first capacitor C1, the negative terminal of the fourth diode D4, one end of the relay J1, and the negative terminal of the fifth diode D5. The other end of the first capacitor C1 is grounded. The other end of the relay J1 is connected to the positive terminal of the fifth diode D5, the source terminal of the first MOSFET V1, the drain terminal of the first MOSFET V1 is grounded, the gate terminal of the first MOSFET V1 is connected to the positive terminal of the fourth diode D4, and the output terminal of the AND gate U6. One end of the input terminal of the AND gate U6 is connected to the output terminal of the circuit breaker detection module 5, and the other end of the input terminal of the AND gate U6 is connected to the second output terminal of the safety detection module 6.

[0062] When the power supply module 1 is supplying power normally, the circuit breaker detection module 5 and the safety detection module 6 output a high level, which makes the AND gate U6 conduct and output a high level. Through the fourth diode D4 and the sixth resistor R6, the first thyristor Z1 is controlled to conduct, thus supplying power to the load.

[0063] When the power supply module 1 is abnormal, the circuit breaker detection module 5 and the safety detection module 6 output a low level, the AND gate U6 is cut off, the first MOSFET V1 is turned on, the first capacitor C1 stores electrical energy to power the relay J1, causing the first switch S1 to open and stop supplying power to the load; after the first capacitor C1 is insufficient to support the operation of the relay J1, the first thyristor Z1 is turned off again, and still no power is supplied to the load.

[0064] When circuit breaker U5 fails, the output signal becomes questionable due to the fault of circuit breaker U5. At this time, due to the presence of safety detection module 6, the circuit can be effectively disconnected in conjunction with AND gate U6 to prevent the load from still being powered when the power supply module 1 is abnormal.

[0065] When the power supply module 1 is abnormal, the circuit breaker U5 continuously outputs a high level to the AND gate U6. At this time, since the safety detection module 6 still outputs a low level, the AND gate U6 does not conduct and stops supplying power to the load.

[0066] The circuit breaker U5 continuously outputs a low level, which also prevents the AND gate U6 from conducting, thus stopping the power supply to the load.

[0067] In another embodiment: the fifth diode D5 can be omitted. The fifth diode D5 serves as a freewheeling diode, effectively discharging the large current during the instantaneous conduction and disconnection of the relay J1.

[0068] The working principle of this invention is as follows: Power supply module 1 supplies voltage; power-on protection module 2 prevents current surges during power-on; drive resistance reduction module 3 reduces the resistance of power-on protection module 2 after power-on delay; current sampling output module 4 samples the current output to circuit breaker detection module 5 and converts it into a voltage signal for output to safety detection module 6; circuit breaker detection module 5 outputs different signals to on / off control output module 7 based on different conditions of the power supply module 1's output current (normal, exceeding the upper threshold, or below the lower threshold); safety detection module 6 outputs different signals to on / off control output module 7 based on the voltage signal corresponding to the sampled current, reflecting the magnitude of the power supply module 1's output current, based on different conditions of the output current (normal, exceeding the upper threshold, or below the lower threshold); on / off control output module 7 controls whether to supply power to the load based on the different signals output by circuit breaker detection module 5 and safety detection module 6. This invention adds peripheral circuitry to circuit breaker U5, using circuit breaker U5 as a detection device, effectively disconnecting the circuit and stopping power supply to the load when the power supply is abnormal. Furthermore, the potential drop is small during the process of power supply module 1's output voltage supplying the load voltage, effectively ensuring the load's operating voltage.

[0069] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0070] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A safety protection low-voltage circuit breaker circuit, characterized in that: The safety protection low-voltage circuit breaker circuit includes: The power supply module is used to supply voltage; Power-on protection module, used to prevent sudden current surges when power is applied; The drive resistance reduction module is used to reduce the resistance of the power-on protection module after the power-on delay. The current sampling output module is used to sample the current output to the circuit breaker detection module and convert it into a voltage signal for output to the safety detection module. The circuit breaker detection module is used to output different signals to the on / off control output module according to different conditions of the power supply module output current: normal, exceeding the upper limit threshold, or below the lower limit threshold. The safety detection module is used to output different signals to the on / off control output module based on the voltage signal corresponding to the sampled current, which reflects the output current of the power supply module. The output current is normal, exceeds the upper limit threshold, or is below the lower limit threshold. The on / off control output module is used to control whether to supply power to the load based on different signals output by the circuit breaker detection module and the safety detection module; The output terminal of the power supply module is connected to the first input terminal of the power-on protection module. The output terminal of the power-on protection module is connected to the input terminal of the current sampling output module. The first output terminal of the current sampling output module is connected to the input terminal of the circuit breaker detection module and the first input terminal of the on / off control output module. The second output terminal of the current sampling output module is connected to the input terminal of the safety detection module. The first output terminal of the safety detection module is connected to the input terminal of the drive resistance reduction module. The output terminal of the drive resistance reduction module is connected to the second input terminal of the power-on protection module. The output terminal of the circuit breaker detection module is connected to the second input terminal of the on / off control output module. The second output terminal of the safety detection module is connected to the third input terminal of the on / off control output module. The drive resistance reduction module includes a seventh resistor, a second capacitor, a seventh inverter, and an eighth inverter. The input terminal of the seventh inverter is connected to one end of the seventh resistor and one end of the second capacitor. The output terminal of the seventh inverter is connected to the other end of the seventh resistor and the input terminal of the eighth inverter. The output terminal of the eighth inverter is connected to the other end of the second capacitor and the second input terminal of the power-on protection module. The power supply terminals of the seventh and eighth inverters are connected to the first output terminal of the safety detection module.

2. The safety protection low-voltage circuit breaker circuit according to claim 1, characterized in that, The power-on protection module includes a first resistor, a second thyristor, and a first switch. One end of the first resistor is connected to the output terminal of the power supply module and the positive terminal of the second thyristor. The other end of the first resistor is connected to the negative terminal of the second thyristor and one end of the first switch. The other end of the first switch is connected to the input terminal of the current sampling output module. The control terminal of the second thyristor is connected to the output terminal of the drive resistance reduction module.

3. The safety protection low-voltage circuit breaker circuit according to claim 1, characterized in that, The current sampling output module includes a current transformer and a fifth resistor. The first end of the current transformer is connected to the output end of the power-on protection module, the second end of the current transformer is connected to the input end of the circuit breaker detection module and the first input end of the on / off control output module, the third end of the current transformer is connected to one end of the fifth resistor, and the other end of the fifth resistor is connected to the fourth end of the current transformer and the input end of the safety detection module.

4. The safety protection low-voltage circuit breaker circuit according to claim 1, characterized in that, The circuit breaker detection module includes a circuit breaker. The input terminal of the circuit breaker is connected to the first output terminal of the current sampling output module, and the output terminal of the circuit breaker is connected to the second input terminal of the on / off control output module.

5. The safety protection low-voltage circuit breaker circuit according to claim 1, characterized in that, The security detection module includes: The upper limit threshold detection module is used to output a low level to the on / off control output module when the output current exceeds the upper limit threshold. The lower threshold detection module is used to output a low level to the on / off control output module when the output current is lower than the lower threshold. The upper limit threshold detection module and the lower limit threshold detection module are connected in parallel.

6. The safety protection low-voltage circuit breaker circuit according to claim 5, characterized in that, The threshold exceedance detection module includes a fourth resistor, a third diode, a second amplifier, and a fourth inverter. One end of the fourth resistor is connected to the output terminal of the power-on protection module, and the other end of the fourth resistor is connected to the negative terminal of the third diode and the inverting terminal of the second amplifier. The positive terminal of the third diode is grounded. The non-inverting terminal of the second amplifier is connected to the second output terminal of the current sampling output module. The output terminal of the second amplifier is connected to the input terminal of the fourth inverter. The output terminal of the fourth inverter is connected to the third input terminal of the on / off control output module.

7. The safety protection low-voltage circuit breaker circuit according to claim 5, characterized in that, The lower threshold detection module includes a second resistor, a third resistor, a second diode, and a third amplifier. One end of the second resistor is connected to the output terminal of the power-on protection module, and the other end of the second resistor is connected to one end of the third resistor. The other end of the third resistor is connected to the negative terminal of the second diode, the input terminal of the drive resistance reduction module, and the inverting terminal of the third amplifier. The positive terminal of the second diode is grounded. The non-inverting terminal of the third amplifier is connected to the second output terminal of the current sampling output module, and the output terminal of the third amplifier is connected to the third input terminal of the on / off control output module.

8. The safety protection low-voltage circuit breaker circuit according to claim 1, 6, or 7, characterized in that, The on / off control output module includes an AND gate, a fourth diode, a relay, a first MOSFET, a fifth diode, a first capacitor, a sixth resistor, and a first thyristor. The positive terminal of the first thyristor is connected to the first output terminal of the current sampling output module, and the negative terminal of the first thyristor is connected to the load. The control terminal of the first thyristor is connected to one end of the sixth resistor. The other end of the sixth resistor is connected to one end of the first capacitor, the negative terminal of the fourth diode, one end of the relay, and the negative terminal of the fifth diode. The other end of the first capacitor is grounded. The other end of the relay is connected to the positive terminal of the fifth diode, the source terminal of the first MOSFET, the drain terminal of the first MOSFET, and the gate terminal of the first MOSFET is connected to the positive terminal of the fourth diode. The output terminal of the AND gate is connected to one end of the input terminal of the AND gate, and the other end of the input terminal of the AND gate is connected to the second output terminal of the safety detection module.

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