Power supply circuit and circuit breaker

Abstract

A voltage control module of the power supply circuit is used for transmitting an induced voltage to a constant voltage output module when the induced voltage is less than a preset stabilized voltage, and is switched on and stops outputting the induced voltage when the induced voltage is greater than the preset stabilized voltage. The constant voltage output module discharges to output a preset constant voltage; the induced voltage is obtained according to the induced current of the secondary side of the current transformer; the current sampling module is used for sampling induced current to obtain an amplified voltage signal; the control module is used for obtaining the actual current of the primary side of the current transformer according to the amplified voltage signal, and generating a control signal when the actual current is greater than a preset current threshold value; the switch protection module is used for responding to the control signal and switching between connection and disconnection so as to share energy of the voltage control module during connection. The power supply circuit is high in stability, energy is shared through conduction of the switch protection module in heavy load, and safety and reliability of the circuit are improved.

Description

Technical Field

[0001] This application relates to the field of circuit breaker technology, specifically to a power supply circuit and a circuit breaker. Background Technology

[0002] Currently, the self-generated power supply circuit of the current transformer in electronic circuit breakers typically uses a hardware control circuit composed of operational amplifiers.

[0003] However, in the related technologies, the hardware control circuit is prone to unstable DC power supply voltage and weak load-carrying capacity when the main circuit is lightly loaded due to the periodic operation of the switching transistor. Under heavy load, the switching transistor is prone to overheating and damage due to the long-term conduction state. Utility Model Content

[0004] In view of the above problems, this application provides a power supply circuit and a circuit breaker to solve the above technical problems.

[0005] In a first aspect, this application provides a power supply circuit, which includes a voltage control module, a switch protection module, a constant voltage output module, a current sampling module, and a control module. The voltage control module is connected to the secondary side of a current transformer and the constant voltage output module, respectively, and is used to transmit the induced voltage to the constant voltage output module to charge the constant voltage output module when the induced voltage is less than a preset regulated voltage; and to turn on and stop outputting the induced voltage when the induced voltage is greater than the preset regulated voltage, so that the constant voltage output module discharges and outputs a preset constant voltage. The induced voltage is obtained based on the induced current on the secondary side of the current transformer. The current sampling module is connected to the secondary side of the current transformer and the control module, respectively, and is used to sample the induced current and obtain an amplified voltage signal based on the induced current, which is then output to the control module. The control module is connected to the switch protection module and is used to obtain the actual current on the primary side of the current transformer based on the amplified voltage signal, and to generate a control signal to output to the switch protection module when the actual current is greater than a preset current threshold. The switch protection module is connected in parallel with the voltage control module and is used to switch between on and off in response to the control signal, so as to share the energy of the voltage control module when it is on.

[0006] In one possible implementation of this application, the voltage control module includes a voltage regulator unit and a first switching unit. The first terminal of the voltage regulator unit, the first terminal of the first switching unit, the secondary side of the current transformer, and the constant voltage output module are connected. The second terminal of the voltage regulator unit, the second terminal of the first switching unit, and the ground terminal are connected. The third terminal of the voltage regulator unit is connected to the third terminal of the first switching unit. The voltage regulator unit is used to turn on when the induced voltage is greater than a preset voltage regulator to output a first level signal to the first switching unit, and to turn off when the first switching unit is turned off, so as to output the induced voltage. The first switching unit is used to turn on in response to the first level signal to stop outputting the induced voltage, and to turn off when the current voltage of the constant voltage output module is less than a preset constant voltage.

[0007] In one possible implementation of this application, the voltage regulating unit includes a Zener diode and a grounding resistor, and the first switching unit includes a first switching transistor. The cathode of the Zener diode, the first terminal of the first switching transistor, the secondary side of the current transformer, and the constant voltage output module are connected together. The anode of the Zener diode is connected to the first terminal of the grounding resistor and the control terminal of the first switching transistor, respectively. The second terminal of the first switching transistor and the second terminal of the grounding resistor are connected to the grounding terminal.

[0008] In one possible implementation of this application, the switch protection module includes a second switch unit, the first terminal of the second switch unit is connected to the first terminal of the voltage control module, the second terminal of the second switch unit is connected to the ground terminal, and the control terminal of the second switch unit is connected to the output terminal of the control module; the second switch unit is used to switch between on and off in response to a control signal, so as to share the energy of the voltage control module when on.

[0009] In one possible implementation of this application, the second switching unit includes a second switching transistor, the control terminal of the second switching transistor is connected to the output terminal of the control module, the first terminal of the second switching transistor is connected to the first terminal of the voltage control module, and the second terminal of the second switching transistor is connected to the ground terminal.

[0010] In one possible implementation of this application, the constant voltage output module includes an energy storage capacitor unit. The first terminal of the energy storage capacitor unit, the first terminal of the voltage control module, and the first terminal of the switch protection module are connected together, and the second terminal of the energy storage capacitor unit is connected to the ground terminal. The energy storage capacitor unit is used for charging based on the induced voltage and outputting a preset constant voltage.

[0011] In one possible implementation of this application, the current sampling module includes a current sampling unit and an amplification and follower unit; the current sampling unit is connected to the secondary side of the current transformer and is used to sample the induced current and obtain a sampled voltage signal based on the induced current; the amplification and follower unit is connected to the current sampling unit and the control module respectively and is used to amplify and follow the sampled voltage signal to obtain an amplified voltage signal output to the control module.

[0012] In one possible implementation of this application, the current sampling unit includes a sampling resistor. The first end of the sampling resistor is connected to the secondary side of the current transformer and the input end of the amplification and follower unit, respectively, and the second end of the sampling resistor is connected to the ground terminal.

[0013] In one possible implementation of this application, the amplification follower unit includes an inverting amplifier and a voltage follower. The inverting input of the inverting amplifier is connected to the current sampling unit to receive the sampled voltage signal. The output of the inverting amplifier is connected to the non-inverting input of the voltage follower, and the output of the voltage follower is connected to the control module. The inverting amplifier is used to amplify the sampled voltage signal to obtain an amplified voltage signal, which is then output to the voltage follower. The voltage follower is used to perform voltage following on the sampled voltage signal and output the sampled voltage signal to the control module.

[0014] Secondly, this application also provides a circuit breaker including a current transformer and a power supply circuit in any possible implementation of the first aspect connected to the current transformer.

[0015] From the above, it can be concluded that this application has the following beneficial effects:

[0016] In this application, the voltage control module and the constant voltage output module work together to enable the power supply circuit to stably output a preset constant voltage under light load, thereby improving stability. Furthermore, the current sampling module samples the induced current on the secondary side of the current transformer and obtains an amplified voltage signal, which is then output to the control module. The control module obtains the actual current on the primary side of the current transformer based on the amplified voltage signal. When the actual current exceeds a preset current threshold, it generates a control signal and outputs it to the switch protection module. This allows the switch protection module to share the energy of the voltage control module when it is turned on based on the control signal, preventing the voltage control module from overheating and being damaged under heavy load, thus improving circuit safety and reliability. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic block diagram of a power supply circuit provided in an embodiment of this application;

[0019] Figure 2 This is a schematic block diagram of a voltage control module provided in an embodiment of this application;

[0020] Figure 3 This is a schematic diagram of a power supply circuit provided in an embodiment of this application;

[0021] Figure 4 This is a circuit block diagram of a switch protection module provided in the embodiments of this application;

[0022] Figure 5 This is a schematic diagram of a constant voltage output module provided in the embodiments of this application;

[0023] Figure 6 This is a schematic diagram of a current sampling module provided in an embodiment of this application. Detailed Implementation

[0024] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0025] To enable those skilled in the art to better understand the solutions of this application, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0026] In the embodiments of this application, it should be noted that, in this document, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0027] Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device that includes said element.

[0028] In the description of the embodiments of this application, the words "example" or "for example" are used to indicate exemplification, illustration, or description. Any embodiment or design described as "example" or "for example" in the embodiments of this application is not to be construed as being more preferred or having more advantages than another embodiment or design. The use of the words "example" or "for example" is intended to present relative concepts in a clear manner.

[0029] Furthermore, in the embodiments of this application, "multiple" refers to two or more. Therefore, in the embodiments of this application, "multiple" can also be understood as "at least two". "At least one" can be understood as one or more, such as one, two, or more. For example, including at least one means including one, two, or more, and is not limited to which ones are included. For example, including at least one of A, B, and C, then it could include A, B, C, A and B, A and C, B and C, or A and B and C.

[0030] It should be noted that in the embodiments of this application, "connection" can be understood as electrical connection. The connection between two electrical components can be a direct or indirect connection between the two electrical components. For example, the connection between A and B can be a direct connection between A and B, or an indirect connection between A and B through one or more other electrical components.

[0031] In the embodiments of this application, the first terminal / first end of each transistor is one of the source and the drain, and the second terminal / second end of each transistor is the other of the source and the drain. Since the source and drain of a transistor can be structurally symmetrical, they can be structurally indistinguishable. That is, the first terminal / first end and the second terminal / second end of the transistor in the embodiments of this application can be structurally indistinguishable. For example, when the transistor is a P-type transistor, the first terminal / first end is the source, and the second terminal / second end is the drain; for example, when the transistor is an N-type transistor, the first terminal / first end is the drain, and the second terminal / second end is the source.

[0032] In the circuit structure provided by the embodiments of this application, nodes such as the first node and the second node do not represent actual existing components, but rather represent the junction points of related couplings in the circuit diagram. In other words, these nodes are equivalent to the junction points of related couplings in the circuit diagram.

[0033] The power supply circuit and circuit breaker provided in this application will be described in detail below.

[0034] First, this application provides a power supply circuit that can be applied to a circuit breaker to control the operation of the circuit breaker.

[0035] Please see Figure 1 , Figure 1 This is a schematic block diagram of a power supply circuit provided in an embodiment of this application. The power supply circuit 100 may include a voltage control module 110, a switch protection module 120, a constant voltage output module 130, a current sampling module 140, and a control module 150. The voltage control module 110 is connected to the secondary side of the current transformer 210 and the constant voltage output module 130, respectively. It is used to transmit the induced voltage to the constant voltage output module 130 to charge the constant voltage output module 130 when the induced voltage is less than a preset regulated voltage; and to turn on and stop outputting the induced voltage when the induced voltage is greater than the preset regulated voltage, so that the constant voltage output module 130 discharges and outputs a preset constant voltage. The induced voltage is determined based on the induced voltage on the secondary side of the current transformer 210. The current is obtained by sampling the induced current. The current sampling module 140 is connected to the secondary side of the current transformer 210 and the control module 150 respectively. It is used to sample the induced current and obtain an amplified voltage signal based on the induced current, which is then output to the control module 150. The control module 150 is connected to the switch protection module 120. It is used to obtain the actual current on the primary side of the current transformer based on the amplified voltage signal, and generate a control signal to output to the switch protection module 120 when the actual current is greater than a preset current threshold. The switch protection module 120 is connected in parallel to the voltage control module 110 and is used to switch between on and off in response to the control signal, so as to share the energy of the voltage control module 110 when it is on.

[0036] The voltage control module 110 is connected to the secondary side of the current transformer 210. It can be understood that the current transformer 210 can convert the large current on the primary side, i.e. the main circuit, into a milliampere-level current, thereby forming an induced current on the secondary side. Since there is always impedance in the circuit, the induced voltage output can be obtained based on this induced current.

[0037] It is worth noting that if the induced voltage is an AC voltage, it can be rectified into a DC voltage output by a rectifier such as a rectifier bridge. If the induced voltage is a DC voltage, it can be directly connected to the voltage control module 110.

[0038] Under light load, when the input induced voltage is less than the preset regulated voltage, the induced voltage is directly transmitted to the constant voltage output module 130 for charging; when the induced voltage is greater than the preset regulated voltage, the voltage control module 110 can be turned on. After being turned on, the voltage control module 110 pulls the first node N1 down to ground, thereby turning off the voltage control module 110, causing the voltage of the first node N1 to gradually rise.

[0039] When the voltage of the first node N1 exceeds the preset regulated voltage again, the voltage control module 110 is turned on again, stopping the charging of the constant voltage output module 130. At this time, the constant voltage output module 130 can discharge based on the stored electrical energy and output a preset constant voltage.

[0040] The current sampling module 140 is connected to the secondary side of the current transformer 210, so that it can sample the induced current and perform a series of processing on the induced current, such as current-to-voltage conversion, filtering, amplification, etc., to obtain an amplified voltage signal output to the control module 150.

[0041] In this embodiment, the control module 150 can be any existing controller such as a microcontroller unit (MCU), a system on chip (SOC), or a single-chip microcomputer. The specific controller can be determined according to the actual application scenario and is not limited here.

[0042] After receiving the amplified voltage signal, the control module 150 can perform analysis, filtering, and other processing to obtain the actual current on the primary side of the current transformer 210. Based on this actual current, the current load condition is determined. For example, if the actual current is greater than the preset current threshold, it can be determined that the main circuit is under heavy load. Therefore, a control signal can be generated and output to the switch protection module 120, so that the switch protection module 120 can periodically turn on or off in response to the control signal. This way, when the switch is on, the energy of the voltage control module 110 is shared, and the voltage control module 110 is prevented from overheating under heavy load.

[0043] In this embodiment, the control signal can be a pulse width modulation (PWM) signal with adjustable frequency and duty cycle. The frequency and duty cycle of the control signal can be adjusted according to the actual application scenario, and are not limited here.

[0044] In this embodiment, the voltage control module 110 works in conjunction with the constant voltage output module 130 to enable the power supply circuit 100 to stably output a preset constant voltage under light load, thereby improving stability. Furthermore, the current sampling module 140 samples the induced current on the secondary side of the current transformer 210 and outputs an amplified voltage signal to the control module 150. The control module 150 obtains the actual current on the primary side of the current transformer 210 based on the amplified voltage signal. When the actual current exceeds a preset current threshold, it generates a control signal and outputs it to the switch protection module 120. This allows the switch protection module 120 to share the energy of the voltage control module 110 when it is turned on based on the control signal, preventing the voltage control module 110 from overheating and being damaged under heavy load, thus improving circuit safety and reliability.

[0045] Next, continue with Figure 1 The unit modules shown are described in detail, as well as the specific implementation methods that may be used in practical applications.

[0046] like Figure 2 As shown, in some embodiments of this application, the voltage control module 110 may include a voltage regulator unit 1101 and a first switching unit 1102. The first terminal of the voltage regulator unit 1101, the first terminal of the first switching unit 1102, the secondary side of the current transformer 210, and the constant voltage output module 130 are connected. The second terminal of the voltage regulator unit 1101, the second terminal of the first switching unit 1102, and the ground terminal GND are connected. The third terminal of the voltage regulator unit 1101 is connected to the third terminal of the first switching unit 1102. The voltage regulator unit 1101 can be turned on when the induced voltage is greater than a preset voltage regulator to output a first level signal to the first switching unit 1102, and turned off when the first switching unit 1102 is turned off to output the induced voltage. The first switching unit 1102 can be turned on in response to the first level signal to stop outputting the induced voltage, and turned off when the current voltage of the constant voltage output module 130 is less than a preset constant voltage.

[0047] The voltage regulator unit 1101 may include any existing voltage regulator diode, and the first switching unit 1102 may include any existing switching transistor, such as a transistor, a metal-oxide-semiconductor field-effect transistor (MOSFET), an insulated-gate bipolar transistor (IGBT), etc. The specific type can be selected according to the actual application scenario, and no limitation is made here.

[0048] In this embodiment of the application, the voltage stabilizing unit 1101 can control the first switching unit 1102 to be turned on or off. When the first switching unit 1102 is turned on, the first node N1 can be pulled down to ground. Conversely, when the first switching unit 1102 is turned off, the driving voltage can be output to the constant voltage output module 130, so that the constant voltage output module 130 can be charged and stored.

[0049] like Figure 3 As shown, for three-phase AC power, the control of phases A, B, and C is the same; therefore, this embodiment uses phase A as an example for explanation. In one implementation, the voltage regulator unit 1101 may include a Zener diode ZD1 and a grounding resistor R9, and the first switching unit 1102 may include a first switching transistor Q2; in this embodiment, the first switching transistor Q2 is an NPN transistor.

[0050] The cathode of Zener diode ZD1, the first terminal of the first switching transistor Q2, the secondary side of current transformer 210, and constant voltage output module 130 are connected. The anode of Zener diode ZD1 is connected to the first terminal of grounding resistor R9 and the control terminal of the first switching transistor Q2. The second terminal of the first switching transistor Q2 and the second terminal of grounding resistor R9 are connected to ground terminal GND.

[0051] When the induced voltage is greater than the Zener diode ZD1's regulated voltage, the Zener diode ZD1 conducts, generating a voltage drop across the grounding resistor R9. This outputs a first-level signal, such as a high-level signal, which turns on the first switching transistor Q2, pulling down the VPP voltage at the first node N1. At this time, the Zener diode ZD1 is not conducting, the first switching transistor Q2 is off, and the VPP voltage at the first node N1 continues to be output to the constant voltage output module 130 to charge it.

[0052] like Figure 4 As shown, in some embodiments of this application, the switch protection module 120 may include a second switch unit 1201. The first end of the second switch unit 1201 is connected to the first end of the voltage control module 110, the second end of the second switch unit 1201 is connected to the ground terminal GND, and the control terminal of the second switch unit 1201 is connected to the output terminal of the control module 150. The second switch unit 1201 can be used to switch between on and off in response to a control signal, so as to share the energy of the voltage control module 110 when on.

[0053] In this embodiment, the second switching unit 1201 may include any existing switching transistor, such as a triode, MOSFET, IGBT, etc. The specific type can be selected according to the actual application scenario, and is not limited here.

[0054] The control module 150 obtains the actual current on the primary side of the current transformer 210 based on the amplified voltage signal. When a heavy load is determined based on the actual current, the frequency and duty cycle of the control signal are adjusted so that the second switching unit 1201 responds to the control signal to switch between on and off states, thereby sharing the energy of the first switching unit 1102 and preventing the first switching unit 1102 from overheating due to prolonged on-time conduction.

[0055] Please continue reading. Figure 3 As an example, the second switching unit 1201 may include a second switching transistor Q1. In this example, the second switching transistor Q1 is an NMOS transistor. The control terminal of the second switching transistor Q1 is connected to the output terminal of the control module 150 and connected to the control signal MCU_CTL. The first terminal of the second switching transistor Q1 is connected to the first terminal of the voltage control module 110, and the second terminal of the second switching transistor Q1 is connected to the ground terminal GND.

[0056] When the primary circuit load exceeds a certain level, i.e., a heavy load, the primary current increases, and the secondary current output by the current transformer 210 also increases accordingly. The conduction time of the first switching transistor Q2 also increases accordingly. Long-term operation will inevitably cause it to heat up or even burn out. At this time, the current sampling module 140 synchronously collects the induced current on the secondary side and outputs an amplified voltage signal to the control module 150 based on the induced current. The control module 150 performs analysis, filtering and other processing on the amplified voltage signal to obtain the actual current on the primary side. Based on the magnitude of the actual current, it adjusts the period and duty cycle of the control signal MCU_CTL so that the second switching transistor Q1 is also in a periodic working state. When the second switching transistor Q1 is turned on, some energy exists in the gate and drain of the second switching transistor Q1, which can indirectly share the heat of the first switching transistor Q2, relieve the pressure on the first switching transistor Q2, and protect the first switching transistor Q2 from burning out due to overheating.

[0057] like Figure 5 As shown, in some embodiments of this application, the constant voltage output module 130 may include an energy storage capacitor unit 1301. The first end of the energy storage capacitor unit 1301 is connected to the first end of the voltage control module 110 and the first end of the switch protection module 120. The second end of the energy storage capacitor unit 1301 is connected to the ground terminal GND. The energy storage capacitor unit 1301 can be used for charging based on induced voltage and outputting a preset constant voltage.

[0058] In this embodiment of the application, the energy storage capacitor unit 1301 may include one or more energy storage capacitors connected in series, and a stable preset constant voltage output can be achieved by charging and discharging the energy storage capacitors.

[0059] like Figure 3As shown, as an example, the energy storage capacitor unit 1301 includes a first energy storage capacitor CE1. The positive terminal of the first energy storage capacitor CE1 is connected to the first switching transistor Q2 and the second switching transistor Q1 through the first diode D1. When the first energy storage capacitor CE1 discharges, it outputs a preset constant voltage of +12V to power the subsequent circuit. The subsequent circuit here can be a circuit breaker tripping circuit.

[0060] like Figure 6 As shown, in some embodiments of this application, the current sampling module 140 may include a current sampling unit 1401 and an amplification and following unit 1402. The current sampling unit 1401 is connected to the secondary side of the current transformer 210 and can be used to sample the induced current and obtain a sampled voltage signal based on the induced current. The amplification and following unit 1402 is connected to the current sampling unit 1401 and the control module 150 respectively and can be used to amplify and voltage follow the sampled voltage signal to obtain an amplified voltage signal that is output to the control module 150.

[0061] In this embodiment, the current sampling unit 1401 can be any existing current sampling device or current sampling circuit. The current sampling unit 1401 samples the induced current on the secondary side of the current transformer 210 and outputs the corresponding sampling voltage signal to the amplification and follower unit 1402.

[0062] The amplification and following unit 1402 can amplify, voltage follow, filter and other processes the received sampled voltage signal to obtain an amplified voltage signal and output it to the control module 150.

[0063] After receiving the amplified voltage signal, the control module 150 can perform analysis, filtering and other processing to obtain the actual current on the primary side. Based on the actual current, it can determine the current load condition. Under heavy load, it can output a control signal to control the second switching unit 1201 to periodically turn on or off in coordination with the first switching unit 1102, so as to share the energy of the first switching unit 1102.

[0064] Please continue to refer to Figure 3 As an example, the current sampling unit 1401 may include a sampling resistor R7. The first end of the sampling resistor R7 is connected to the secondary side of the current transformer 210 and the input end of the amplification follower unit 1402, respectively. The second end of the sampling resistor R7 is connected to the ground terminal GND. The induced current is sampled through the sampling resistor R7 and converted into a sampling voltage signal.

[0065] like Figure 3As shown in some embodiments of this application, the amplification and following unit 1402 may include an inverting amplifier U1C, a voltage follower U1D, and corresponding peripheral circuits. The inverting input terminal of the inverting amplifier U1C is connected to the current sampling unit 1401, i.e., the sampling resistor R7, through the second resistor R2 and the first resistor R1, to receive the sampling voltage signal. The output terminal of the inverting amplifier U1C is connected to the non-inverting input terminal of the voltage follower U1D, and the output terminal of the voltage follower U1D is connected to the sampling interface MCU_ADC1 of the control module 150. The inverting amplifier U1C can be used to amplify the sampling voltage signal to obtain an amplified voltage signal output to the voltage follower U1D. The voltage follower U1D can be used to voltage follow the sampling voltage signal and output the sampling voltage signal to the control module 150.

[0066] In this embodiment, both the inverting amplifier U1C and the voltage follower U1D can be implemented using existing chips. The current transformer 210 converts the main circuit current into a small current signal, which is output from the secondary side. After passing through the sampling resistor R7, it is converted into a sampling voltage signal. This sampling voltage signal is amplified by the inverting amplifier U1C and followed by the voltage follower U1D. After passing through the RC filter, it is transmitted without distortion to the digital-to-analog converter unit inside the control module 150. The control module 150 converts the received amplified voltage signal into a digital signal and filters it through a digital filter to obtain the induced current. Based on the induced current, the current load condition is determined. Thus, the operating frequency and pulse width of the second switching transistor Q1 are adjusted in real time through the control signal MCU_CTL to achieve the purpose of stabilizing the output voltage and realizing high-precision sampling. Figure 3 D2 is a transient suppression diode, C12 is an input signal filter capacitor, and C17 is a phase compensation capacitor.

[0067] In this embodiment, the power supply circuit turns off the second switching transistor Q1 when the main circuit load is light. As the load increases, the second switching transistor Q1 operates periodically. The current sampling module 140 collects the induced current in real time, and after current-to-voltage conversion and amplification, transmits it to the control module 150. The control module 150 calculates the actual primary current and adjusts the operating cycle and pulse width of the second switching transistor Q1 according to the actual current to improve sampling accuracy. It is worth noting that the software portion of this application can be implemented using existing technology, and the scope of protection of this application does not involve the software solution.

[0068] Based on the power supply circuit in the above embodiments, and building upon those embodiments, this application also provides a circuit breaker, which may include a current transformer and a circuit breaker connected to the current transformer, such as... Figures 1 to 6 This corresponds to the power supply circuit in any embodiment. The circuit breaker can be an electronic circuit breaker, such as an electronic molded case circuit breaker.

[0069] Because the circuit breaker includes the present application, as described in this application Figures 1 to 6 Corresponding to the power supply circuit in any embodiment, the present application can be implemented as described above. Figures 1 to 6 For all the beneficial effects that the power supply circuit can achieve in any embodiment, please refer to the preceding description, which will not be repeated here.

[0070] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Although this application has disclosed preferred embodiments as above, it is not intended to limit this application. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the technical solution of this application. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. A power supply circuit, characterized by comprising: The voltage control module, the switch protection module, the constant voltage output module, the current sampling module and the control module are included. The voltage control module is connected with the secondary side of the current transformer and the constant voltage output module, and is used for transmitting the induced voltage to the constant voltage output module when the induced voltage is less than the preset stable voltage, so as to charge the constant voltage output module. When the induced voltage is greater than the preset stable voltage, the switch protection module is turned on, and the output of the induced voltage is stopped, so that the constant voltage output module is discharged to output the preset constant voltage. The induced voltage is obtained according to the induced current of the secondary side of the current transformer. The current sampling module is connected with the secondary side of the current transformer and the control module, and is used for sampling the induced current and obtaining an amplified voltage signal output to the control module according to the induced current. The control module is connected with the switch protection module, and is used for obtaining the actual current of the primary side of the current transformer according to the amplified voltage signal, and generating a control signal output to the switch protection module when the actual current is greater than a preset current threshold.

2. The power supply circuit of claim 1, wherein The switch protection module is connected in parallel with the voltage control module, and is used for switching between turn-on and turn-off in response to the control signal to share the energy of the voltage control module when the switch protection module is turned on. The voltage control module includes a voltage stabilizing unit and a first switch unit, the first end of the voltage stabilizing unit, the first end of the first switch unit, the secondary side of the current transformer and the constant voltage output module are connected, the second end of the voltage stabilizing unit, the second end of the first switch unit and the ground terminal are connected, and the third end of the voltage stabilizing unit is connected with the third end of the first switch unit. The voltage stabilizing unit is used for turning on when the induced voltage is greater than the preset stable voltage, outputting a first level signal to the first switch unit, and turning off when the first switch unit is turned off, so as to output the induced voltage.

3. The power supply circuit of claim 2, wherein, The first switch unit is used for turning on in response to the first level signal to stop outputting the induced voltage, and turning off when the current voltage of the constant voltage output module is less than the preset constant voltage. The voltage stabilizing unit includes a voltage stabilizing diode and a grounding resistor, and the first switch unit includes a first switch transistor.

4. The power supply circuit of claim 1, wherein The cathode of the voltage stabilizing diode, the first end of the first switch transistor, the secondary side of the current transformer and the constant voltage output module are connected, the anode of the voltage stabilizing diode is connected with the first end of the grounding resistor and the control end of the first switch transistor, and the second end of the first switch transistor and the second end of the grounding resistor are connected with the ground terminal. The switch protection module includes a second switch unit, the first end of the second switch unit is connected with the first end of the voltage control module, the second end of the second switch unit is connected with the ground terminal, and the control end of the second switch unit is connected with the output end of the control module. The second switch unit is used for switching between turn-on and turn-off in response to the control signal to share the energy of the voltage control module when the switch protection module is turned on.

5. The power supply circuit of claim 4, wherein, The second switch unit comprises a second switch transistor, a control end of the second switch transistor is connected with an output end of the control module, a first end of the second switch transistor is connected with a first end of the voltage control module, and a second end of the second switch transistor is connected with the ground end.

6. The power supply circuit of claim 1, wherein The constant voltage output module comprises an energy storage capacitor unit, a first end of the energy storage capacitor unit, the first end of the voltage control module, and the first end of the switch protection module are connected, and a second end of the energy storage capacitor unit is connected with the ground end. The energy storage capacitor unit is configured to charge and output the preset constant voltage based on the induced voltage.

7. The power supply circuit of claim 1, wherein The current sampling module comprises a current sampling unit and an amplification and follow-up unit. The current sampling unit is connected to a secondary side of the current transformer and is configured to sample the induced current and obtain a sampling voltage signal according to the induced current. The amplification and follow-up unit is connected with the current sampling unit and the control module respectively and is configured to amplify and process the sampling voltage signal and voltage follow-up process the sampling voltage signal to obtain the amplified voltage signal output to the control module.

8. The power supply circuit of claim 7, wherein, The current sampling unit comprises a sampling resistor, a first end of the sampling resistor is connected with the secondary side of the current transformer and an input end of the amplification and follow-up unit respectively, and a second end of the sampling resistor is connected with the ground end.

9. The power supply circuit of claim 7, wherein, The amplification and follow-up unit comprises an inverting proportional amplifier and a voltage follower, an inverting input end of the inverting proportional amplifier is connected with the current sampling unit to access the sampling voltage signal, an output end of the inverting proportional amplifier is connected with a non-inverting input end of the voltage follower, and an output end of the voltage follower is connected with the control module. The inverting proportional amplifier is configured to amplify the sampling voltage signal to obtain the amplified voltage signal output to the voltage follower. The voltage follower is configured to voltage follow the sampling voltage signal and output the sampling voltage signal to the control module.

10. A circuit breaker characterized by, The power supply circuit comprises a current transformer and the power supply circuit according to any one of claims 1-9 connected with the current transformer.

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