Self-power-taking circuit of current transformer and circuit breaker
By introducing rectifier circuits and leakage voltage regulator circuits into the current transformer self-ear circuit, the consistency between the output power and the load consumption power is achieved, ensuring that the current transformer works in the best state, and protecting measures to prevent overvoltage and damage.
Patent Information
- Application Number
- CN202422097098.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-28
- Publication Date
- 2025-06-13
- Estimated Expiration
- 2034-08-28
AI Technical Summary
The existing current transformer self-ear circuit design does not fully consider the consistency between the output power and the load power consumption, resulting in the current transformer being unable to work in the best state.
The input AC current is rectified into DC current by using a rectifier circuit module, and the voltage stabilization process is performed through the leakage voltage stabilization circuit module, including a voltage stabilization power unit, a linear voltage stabilization unit and a leakage voltage stabilization unit. The tracking and automatic flow leakage of the first DC voltage stabilization voltage is achieved through a hysteresis comparator and an electronic switch.
The consistency between the output power of the self-earing circuit and the power consumed by the load is achieved, so that the power draw coil of the current transformer is generated without excess energy, ensuring that the current transformer always works in the best state, and prevents overvoltage and damage through the transient clamping protection unit and the voltage divider circuit.
Smart Images
Figure CN222981417U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of power electronic circuits, in particular to a self-powered circuit of a current transformer applied to a circuit breaker. Background Art
[0002] In some electronic devices (such as circuit breakers) with the function of detecting loop current, it is often through a current transformer connected to a self-powered circuit to generate a working power supply for driving other loads of the electronic device to work. However, the design of the existing self-powered circuit of the current transformer does not fully consider the consistency between the output power of the self-powered circuit and the power consumed by the load, which results in the current transformer for power taking not being able to work in the best state. Summary of the Utility Model
[0003] Therefore, in view of at least one of the above problems, the utility model provides a self-powered circuit of a current transformer and a circuit breaker.
[0004] The utility model is implemented by the following scheme:
[0005] A self-powered circuit of a current transformer is used to process the input current of the current transformer connected thereto into a DC regulated current and output it, including:
[0006] A rectification circuit module, whose input end is connected to the current transformer and the output end is connected to the current-discharge voltage regulation circuit module, is used to rectify the AC current input by the current transformer and output a DC current VCCA;
[0007] The current-discharge voltage regulation circuit module includes a regulated power supply unit, a linear voltage regulation unit and a current-discharge voltage regulation unit, wherein:
[0008] The input end of the regulated power supply unit is connected to the rectification circuit module, and is used to regulate the input DC current VCCA, and the output end outputs a first DC regulated voltage VLOAD for external loads to use;
[0009] The input end of the linear voltage regulation unit is connected to the output end of the regulated power supply unit, and is used to linearly regulate the first DC regulated voltage VLOAD and finally output a reference voltage VREF for the current-discharge voltage regulation unit to use;
[0010] The flow discharge and voltage stabilization unit includes a hysteresis comparator and an electronic switch. The output end of the hysteresis comparator is connected to the switch control end of the electronic switch. The hysteresis comparator is used to dynamically adjust the closing or opening of the switch end of the electronic switch according to the comparison between the input voltage VINPUT after voltage division based on the first DC regulated voltage VLOAD and the reference voltage VREF. The switch end of the electronic switch is connected to the output end of the rectification circuit module, so as to realize the tracking automatic flow discharge of the first DC regulated voltage VLOAD by dynamically adjusting whether the switch is short-circuited or not.
[0011] Among them, in one embodiment, the hysteresis comparator is a non-inverting input hysteresis comparison and amplification circuit constructed by an operational amplifier. Specifically, it includes: an operational amplifier U17 and a feedback resistor R50. The inverting input end of the operational amplifier U17 is connected to the reference voltage VREF, the non-inverting input end of the operational amplifier U17 is connected to the input voltage VINPUT, the feedback resistor R50 is connected between the non-inverting input end and the output end of the operational amplifier U17, and the output end of the operational amplifier U17 is used to connect to the switch control end of the electronic switch.
[0012] Among them, in one embodiment, the linear voltage stabilization unit performs linear voltage stabilization processing on the first DC regulated voltage VLOAD and outputs a second DC regulated voltage VLR. The power supply end of the operational amplifier U17 is connected to the second DC regulated voltage VLR as its working voltage.
[0013] Among them, in one embodiment, the linear voltage stabilization unit performs linear voltage stabilization processing on the first DC regulated voltage VLOAD and outputs a second DC regulated voltage VLR. The linear voltage stabilization unit further includes a first voltage division circuit for further voltage division processing of the second DC regulated voltage VLR to output the reference voltage VREF. The first voltage division circuit is composed of a first voltage division resistor R128 connected between the second DC regulated voltage VLR and the ground wire in series with a second voltage division resistor R131. The intermediate node of the first voltage division resistor R128 and the second voltage division resistor R131 constructs the reference voltage VREF and is connected to the inverting input end of the operational amplifier U17.
[0014] Among them, in one embodiment, the flow discharge and voltage stabilization unit further includes a second voltage division circuit, which is composed of a third voltage division resistor R64 connected between the first DC regulated voltage VLOAD and the ground wire in series with a fourth voltage division resistor R65. The intermediate node of the third voltage division resistor R64 and the fourth voltage division resistor R65 constructs the input voltage VINPUT and is connected to the non-inverting input end of the operational amplifier U17.
[0015] Among them, in one embodiment, the linear voltage regulator unit is a linear voltage regulation circuit constructed by a linear voltage regulator and peripheral resistors. Specifically, it includes: a three-terminal linear voltage regulator U18, an input resistor R49, a first adjustment resistor R62, and a second adjustment resistor R63. The input terminal and the output terminal of the three-terminal linear voltage regulator U18 are connected between the first DC regulated voltage VLOAD and the ground wire via the input resistor R49. The two ends of the series-connected first adjustment resistor R62 and second adjustment resistor R63 are respectively connected to the input terminal and the output terminal of the three-terminal linear voltage regulator U18, and the middle node of the first adjustment resistor R62 and the second adjustment resistor R63 is connected to the adjustment terminal of the three-terminal linear voltage regulator U18.
[0016] Among them, in one embodiment, the electronic switch is a power MOS transistor.
[0017] Among them, in one embodiment, the bleed voltage regulation circuit module further includes a transient voltage clamping protection unit, and the transient voltage clamping protection unit is connected to the front end where the regulated power supply unit accesses the rectifier circuit module.
[0018] Among them, in one embodiment, the transient voltage clamping protection unit is a transient voltage suppression diode TV1, and its two ends are connected to the two output terminals of the rectifier circuit module.
[0019] Among them, in one embodiment, the bleed voltage regulation circuit module further includes a third voltage division circuit, which is composed of a fifth voltage division resistor R129 connected between the first DC regulated voltage VLOAD and the ground wire in series with a sixth voltage division resistor R132, and the middle node of the fifth voltage division resistor R129 and the sixth voltage division resistor R132 is connected to the switch control terminal of the electronic switch.
[0020] And, a circuit breaker is further provided, including: a current transformer for taking power and a self-powered circuit connected thereto; wherein the self-powered circuit is the self-powered circuit of the current transformer as described above.
[0021] Through the technical solution provided by the present utility model, the following technical effects are achieved:
[0022] 1. Compared with the prior art, since a bleed voltage regulation circuit module with a bleed voltage regulator unit is further introduced, automatic bleed tracking of the first DC regulated voltage VLOAD (for external load use) of the regulated power supply unit can be realized. Furthermore, the output power of the self-powered circuit is equal to the power consumed by the load, that is, no extra energy is generated in the power-taking coil of the current transformer, and the extra energy returns the current to the current transformer through the switch short-circuit of the electronic switch to ensure that the power-taking current transformer always operates in the best state;
[0023] 2. Add a transient voltage clamping protection unit to the discharge voltage stabilizing circuit module to prevent the situation where when the load circuit side of an electronic device (such as a circuit breaker) is short-circuited, a transient current is generated, resulting in a transient high-voltage DC current output by the rectification circuit module being applied to the discharging electronic switch, causing it to be damaged due to insufficient voltage withstand capacity.
[0024] 3. Add a voltage dividing circuit to the discharge voltage stabilizing circuit module to control the discharge of the electronic switch by voltage division, preventing overvoltage when the hysteresis comparator at the back end fails to intervene in time. Brief Description of the Drawings
[0025] Figure 1 is the circuit module diagram of an embodiment of the present utility model;
[0026] Figure 2 is the circuit schematic diagram of the rectification circuit module of an embodiment of the present utility model;
[0027] Figure 3 is the circuit schematic diagram of the discharge voltage stabilizing circuit module of an embodiment of the present utility model. Detailed Embodiments
[0028] To further illustrate the embodiments, the present utility model provides drawings. These drawings are part of the disclosure of the present utility model, mainly used to illustrate the embodiments, and can be combined with the relevant descriptions in the specification to explain the operation principle of the embodiments. With reference to these contents, those of ordinary skill in the art should be able to understand other possible embodiments and the advantages of the present utility model. The components in the drawings are not drawn to scale, and similar component symbols are usually used to represent similar components.
[0029] The present utility model will be further described below in conjunction with the drawings and specific embodiments.
[0030] As Figures 1 to 3 shown, the present utility model provides the circuit module diagram of an embodiment of the self-powered circuit of a current transformer. The self-powered circuit of the current transformer in this embodiment is used to process the input current of the connected current transformer into a DC regulated current and output it; specifically, it includes:
[0031] A rectification circuit module 10, whose input end is connected to a current transformer (not shown in the figure, connected through Figure 2 the interfaces J1 - J4), and the output end is connected to the discharge voltage stabilizing circuit module 20, for rectifying the AC current input by the current transformer and outputting a DC current VCCA;
[0032] The current-limiting and voltage-stabilizing circuit module 20 includes a regulated power supply unit 201, a linear voltage-stabilizing unit 202, and a current-limiting and voltage-stabilizing unit 203. Optionally, it further includes a transient voltage clamping protection unit 204 (which will be described in detail later); where:
[0033] The input end of the regulated power supply unit 201 is connected to the rectifier circuit module 10, which is used to stabilize the input DC current VCCA and output a first regulated DC voltage VLOAD for external loads.
[0034] The input end of the linear voltage-stabilizing unit 202 is connected to the output end of the regulated power supply unit 201, which is used to linearly stabilize the first regulated DC voltage VLOAD and output a second regulated DC voltage VLR, and divide the second regulated DC voltage VLR to output a reference voltage VREF for the current-limiting and voltage-stabilizing unit.
[0035] The current-limiting and voltage-stabilizing unit 203 includes a hysteresis comparator and an electronic switch. The output end of the hysteresis comparator is connected to the switch control end of the electronic switch. The hysteresis comparator is used to dynamically adjust the closing or opening of the switch end of the electronic switch according to the comparison between the input voltage VINPUT after dividing the first regulated DC voltage VLOAD and the reference voltage VREF. The switch end of the electronic switch is connected to the output end of the rectifier circuit module, so as to realize the tracking automatic current-limiting of the first regulated DC voltage VLOAD by dynamically adjusting whether the switch is short-circuited or not.
[0036] Compared with the prior art, since the current-limiting and voltage-stabilizing circuit module 20 with the current-limiting and voltage-stabilizing unit 203 is introduced, the tracking automatic current-limiting of the first regulated DC voltage VLOAD (for external loads) of the regulated power supply unit 201 can be realized. Furthermore, the output power of the self-powered circuit is equal to the power consumed by the load, that is, no redundant energy is generated in the power-taking coil of the current transformer, and the redundant energy returns the current to the current transformer through the short-circuiting of the switch of the electronic switch to ensure that the power-taking current transformer always works in the best state.
[0037] Refer to again Figure 2 and Figure 3 As shown, the specific circuits of each module are described as follows:
[0038] In one embodiment, the rectifier circuit module 10 takes the example of connecting four current transformer channels for power supply. They are respectively connected through interfaces J1 - J4. The IA1 - IA2\IB1 - IB2\IC1 - IC2\IN1 - IN2 terminals of interfaces J1 - J4 are respectively connected to the output ports of the current transformers, and the rectifier bridges BD1 - BD4 are respectively used for bootstrap rectification to output the DC voltage VCCA. The number of current transformer channels in this embodiment is four, which can be increased or decreased in other embodiments; the rectifier circuit module 10 in this embodiment is implemented by a full - bridge rectifier circuit, and a half - bridge rectifier circuit can also be used in other embodiments.
[0039] In one embodiment, the regulated power supply unit 201 is composed of a forward - connected single - way diode D29 and a voltage - stabilizing capacitor C114 with a relatively large capacitance value. The DC current VCCA rectified and output by the rectifier circuit module 10 charges the voltage - stabilizing capacitor C114 through the single - way diode D29. After the voltage climbs and stabilizes, a first DC regulated voltage VLOAD for external loads can be output. Other loads in the electronic device (such as a circuit breaker) can be connected to the electrical node where the first DC regulated voltage VLOAD is located to obtain the power supply.
[0040] In one embodiment, the linear voltage - regulating unit 202 is a linear voltage - regulating circuit constructed by a linear regulator and peripheral resistors; specifically, it includes: a three - terminal linear regulator U18 (such as the model TL431 or other adjustable regulators with a reference), an input resistor R49, a first adjustment resistor R62, and a second adjustment resistor R63. The input terminal and the output terminal of the three - terminal linear regulator U18 are connected between the first DC regulated voltage VLOAD and the ground wire through the input resistor R49. The two ends of the series - connected first adjustment resistor R62 and second adjustment resistor R63 are respectively connected to the input terminal and the output terminal of the three - terminal linear regulator U18. The middle node of the first adjustment resistor R62 and the second adjustment resistor R63 with the set resistance - adjustment ratio is connected to the adjustment terminal of the three - terminal linear regulator U18; thus, after linear voltage regulation through the three - terminal linear regulator U18, a second DC regulated voltage VLR with a more stable voltage is output. To further improve the voltage stability of the second DC regulated voltage VLR, a filter capacitor C115 is also connected in parallel between the input terminal and the output terminal of the three - terminal linear regulator U18.
[0041] In one embodiment, the linear voltage regulator unit 202 further includes a first voltage dividing circuit for voltage dividing and processing a reference voltage VREF for use by the current discharging voltage regulator unit 203; it is composed of a first voltage dividing resistor R128 connected between the second DC regulated voltage VLR and the ground wire in series with a second voltage dividing resistor R131, and the intermediate node of the first voltage dividing resistor R128 and the second voltage dividing resistor R131 constructs the reference voltage VREF and is connected to the inverting input terminal of the operational amplifier U17.
[0042] It should be noted that in other embodiments, the linear voltage regulator unit 202 may also directly select a linear voltage regulator of other models that step down to a set voltage value to directly generate the reference voltage VREF, without the need to further voltage divide the second DC regulated voltage VLR linearly regulated and output by the above-mentioned three-terminal linear voltage regulator U18 through the above-mentioned first voltage dividing circuit to output the required reference voltage VREF.
[0043] In one embodiment, the hysteresis comparator of the current discharging voltage regulator unit 203 is a non-inverting input hysteresis comparison and amplification circuit constructed by an operational amplifier. Specifically, it includes: an operational amplifier U17, a feedback resistor R50, and an output resistor R130. The inverting input terminal of the operational amplifier U17 is connected to the reference voltage VREF, the non-inverting input terminal of the operational amplifier U17 is connected to the input voltage VINPUT, the feedback resistor R50 is connected between the non-inverting input terminal and the output terminal of the operational amplifier U17, the output terminal of the operational amplifier U17 is connected in series with the output resistor R130, and the switch control terminal of the electronic switch is connected through the output resistor R130 for switch control. In addition, the power supply terminal of the operational amplifier U17 is connected to the second DC regulated voltage VLR as its operating voltage. The electronic switch in the current discharging voltage regulator unit 203 is a power MOS transistor Q4. Additionally, in order to achieve electrostatic protection, a Zener diode is also connected in parallel between the switch control terminal MOS_EN of the power MOS transistor Q4 and the ground wire for protection.
[0044] In one embodiment, the current discharging voltage regulator unit 203 further includes a second voltage dividing circuit for voltage dividing and sampling to obtain the input voltage VINPUT for use by the current discharging voltage regulator unit 203; it is composed of a third voltage dividing resistor R64 connected between the first DC regulated voltage VLOAD and the ground wire in series with a fourth voltage dividing resistor R65, and the intermediate node of the third voltage dividing resistor R64 and the fourth voltage dividing resistor R65 constructs the input voltage VINPUT and is connected to the non-inverting input terminal of the operational amplifier U17.
[0045] In the circuit of the current-limiting and voltage-stabilizing unit 203, the second DC regulated voltage VLR (such as DC11V) is divided by voltage-dividing resistors R128 and R131 to serve as the reference voltage VREF (such as DC5.4V) to the inverting input terminal of the operational amplifier U17; the first DC regulated voltage VLOAD is sampled by voltage-dividing resistors R64 and R65 and then fed to the non-inverting input terminal of the operational amplifier U17; the feedback resistor R50 and the operational amplifier U17 form a non-inverting input hysteresis comparison and amplification circuit for hysteresis amplification to achieve saturated output. If the rectifier circuit module 201 outputs the first DC regulated voltage VLOAD > the reference voltage VREF * (the resistance value of the third voltage-dividing resistor R64 + the resistance value of the fourth voltage-dividing resistor R65) / the resistance value of the fourth voltage-dividing resistor R65, then after hysteresis amplification, the output voltage (such as DC11V) of the output terminal of the operational amplifier U17 drives the switching control terminal MOS_EN of the power MOS transistor Q4 via the output resistor R130, causing the switching terminal of the power MOS transistor Q4 to close and conduct, short-circuiting the switch to cut off power extraction from the self-powered circuit; when the load consumes power, the voltage of the first DC regulated voltage VLOAD drops, causing the switching terminal of the power MOS transistor Q4 to open (the control logic is opposite to the above process and will not be elaborated further), then the current transformer is connected to the regulated power supply unit 201 again through the rectifier circuit module 10, and the DC current VCCA rectified and output by the rectifier circuit module 10 charges the voltage-stabilizing capacitor C114 through the unidirectional diode D29; throughout this process, the hysteresis comparator of the current-limiting and voltage-stabilizing unit 203 automatically adjusts the duty cycle of the power extraction control of the power MOS transistor Q4 according to the magnitude of the current consumption at the load end, thereby achieving automatic current-limiting tracking of the first DC regulated voltage VLOAD, and thus ensuring that the current transformer for power extraction always operates in the best state.
[0046] In one embodiment, the current-limiting and voltage-stabilizing circuit module 20 may optionally further include a transient voltage clamping protection unit 204, which is connected to the front end of the regulated power supply unit 201 accessing the rectifier circuit module 10. Preferably, the transient voltage clamping protection unit 204 is a transient voltage suppression diode TV1, and its two ends are connected between the two output terminals of the rectifier circuit module 10, that is, between the DC current VCCA output node and the ground wire node. Adding the transient voltage clamping protection unit 204 to the current-limiting and voltage-stabilizing circuit module 20 is to prevent a situation where when the load circuit side of an electronic device (such as a circuit breaker) is short-circuited, a transient current is generated, resulting in a transient high-voltage DC current VCCA rectified and output by the rectifier circuit module 10, which is then applied to the power MOS transistor Q4 for current-limiting, causing it to be damaged due to insufficient voltage withstand.
[0047] In one embodiment, the bleed and voltage stabilizing circuit module 20 may optionally further include a third voltage dividing circuit, which is composed of a fifth voltage dividing resistor R129 and a sixth voltage dividing resistor R132 connected in series between the first DC regulated voltage VLOAD and the ground wire. The middle node of the fifth voltage dividing resistor R129 and the sixth voltage dividing resistor R132 is connected to the switch control terminal of the electronic switch, that is, connected to the switch control terminal MOS_EN of the power MOS transistor Q4. By further introducing the voltage dividing resistor R129, R132 network to control the current bleeding of the power MOS transistor Q4 through voltage division, it is possible to prevent overvoltage from occurring when the hysteresis comparator composed of the operational amplifier U17 at the back end fails to intervene in time.
[0048] In addition, the present invention also provides an electronic device, specifically a circuit breaker, including: a current transformer for power taking and a self-power taking circuit connected thereto; wherein the self-power taking circuit is the self-power taking circuit of the current transformer as described above. Since the self-power taking circuit of the current transformer adopts the above structure, it also has the beneficial technical effects of the self-power taking circuit of the current transformer in the above embodiments.
[0049] Although the present invention has been specifically shown and described in conjunction with the preferred embodiments, those skilled in the art should understand that various changes can be made to the present invention in terms of form and details without departing from the spirit and scope of the present invention defined by the appended claims, and all of them fall within the protection scope of the present invention.
Claims
1. A self-powered circuit for a current transformer, used to process the input current of the current transformer connected thereto into a DC regulated current and output it, characterized in that: include: A rectifier circuit module, whose input end is connected to the current transformer and whose output end is connected to the current leakage and voltage stabilization circuit module, is used to rectify the alternating current input by the current transformer and then output a direct current VCCA; The leakage current stabilization circuit module includes a voltage stabilization power supply unit, a linear voltage stabilization unit and a leakage current stabilization unit, wherein: The input end of the voltage-stabilized power supply unit is connected to the rectifier circuit module, and is used to stabilize the input DC current VCCA, and the output end outputs a first DC regulated voltage VLOAD for use by an external load; The input end of the linear voltage stabilization unit is connected to the output end of the voltage stabilization power supply unit, and is used to perform linear voltage stabilization on the first DC regulated voltage VLOAD and finally output a reference voltage VREF for use by the current bleeder voltage stabilization unit; The current leakage and voltage stabilization unit includes a hysteresis comparator and an electronic switch, wherein the output end of the hysteresis comparator is connected to the switch control end of the electronic switch, and the hysteresis comparator is used to dynamically adjust whether the switch end of the electronic switch is closed or not according to the comparison between the input voltage VINPUT after the first DC regulated voltage VLOAD is divided and the voltage of the reference voltage VREF, and the switch end of the electronic switch is connected to the output end of the rectifier circuit module, thereby realizing the tracking and automatic current leakage of the first DC regulated voltage VLOAD by dynamically adjusting whether the switch is short-circuited or not.
2. The self-powered circuit of the current transformer according to claim 1, characterized in that: The hysteresis comparator is a common-phase input hysteresis comparison amplifier circuit constructed by an operational amplifier, specifically, comprising: an operational amplifier U17 and a feedback resistor R50, wherein the inverting input terminal of the operational amplifier U17 is connected to the reference voltage VREF, the non-inverting input terminal of the operational amplifier U17 is connected to the input voltage VINPUT, the feedback resistor R50 is connected between the non-inverting input terminal and the output terminal of the operational amplifier U17, and the output terminal of the operational amplifier U17 is used to connect to the switch control terminal of the electronic switch.
3. The self-powered circuit of the current transformer according to claim 2, characterized in that: The linear voltage stabilization unit performs linear voltage stabilization on the first DC regulated voltage VLOAD and outputs a second DC regulated voltage VLR. The power supply terminal of the operational amplifier U17 is connected to the second DC regulated voltage VLR as its operating voltage.
4. The self-powered circuit of the current transformer according to claim 2, characterized in that: The linear voltage stabilization unit performs linear voltage stabilization on the first DC regulated voltage VLOAD and outputs a second DC regulated voltage VLR. The linear voltage stabilization unit also includes a first voltage divider circuit for further voltage dividing the second DC regulated voltage VLR to output the reference voltage VREF. The first voltage divider circuit is composed of a first voltage divider resistor R128 connected between the second DC regulated voltage VLR and the ground line and a second voltage divider resistor R131 connected in series. The middle node between the first voltage divider resistor R128 and the second voltage divider resistor R131 constructs the reference voltage VREF and is connected to the inverting input terminal of the operational amplifier U17; and / or The current leakage and voltage stabilization unit also includes a second voltage-dividing circuit, which is composed of a third voltage-dividing resistor R64 connected in series with a fourth voltage-dividing resistor R65 between the first DC regulated voltage VLOAD and the ground line. The intermediate node between the third voltage-dividing resistor R64 and the fourth voltage-dividing resistor R65 constructs the input voltage VINPUT and is connected to the non-inverting input terminal of the operational amplifier U17.
5. The self-powered circuit of the current transformer according to claim 1, characterized in that: The linear voltage regulator unit is a linear voltage regulator circuit constructed by a linear voltage regulator and peripheral resistors, specifically, including: a three-terminal linear voltage regulator U18, an input resistor R49, a first regulating resistor R62 and a second regulating resistor R63, the input end and the output end of the three-terminal linear voltage regulator U18 are connected between the first DC regulated voltage VLOAD and the ground line via the input resistor R49, the two ends of the first regulating resistor R62 and the second regulating resistor R63 connected in series are respectively connected to the input end and the output end of the three-terminal linear voltage regulator U18, and the middle node of the first regulating resistor R62 and the second regulating resistor R63 is connected to the adjustment end of the three-terminal linear voltage regulator U18.
6. The self-powered circuit of the current transformer according to claim 1, characterized in that: The electronic switch is a power MOS tube.
7. The self-powered circuit of the current transformer according to claim 6, characterized in that: The current-discharging and voltage-stabilizing circuit module further includes a transient voltage clamping protection unit, and the transient voltage clamping protection unit is connected to the front end of the voltage-stabilizing power supply unit connected to the rectifier circuit module.
8. The self-powered circuit of the current transformer according to claim 7, characterized in that: The transient voltage clamping protection unit is a transient voltage suppression diode TV1, and two ends of the diode are connected to two output ends of the rectifier circuit module.
9. The self-powered circuit of the current transformer according to claim 1 or 6, characterized in that: The current leakage and voltage stabilization circuit module also includes a third voltage-dividing circuit, which is composed of a fifth voltage-dividing resistor R129 connected in series with a sixth voltage-dividing resistor R132 between the first DC regulated voltage VLOAD and the ground line, and the middle node between the fifth voltage-dividing resistor R129 and the sixth voltage-dividing resistor R132 is connected to the switch control end of the electronic switch.
10. A circuit breaker comprising: A current transformer for drawing electricity and a self-drawing circuit connected thereto, characterized in that the self-drawing circuit is the self-drawing circuit of the current transformer as described in any one of claims 1-9.