No-load control switching power supply circuit based on primary side feedback and circuit breaker

Abstract

The embodiment of the utility model provides a no-load control switching power supply circuit based on primary side feedback and a circuit breaker. The no-load control switching power supply circuit comprises an input circuit, an output circuit and an output circuit, wherein the output end of the input circuit is coupled to a first end of a primary coil; the third end and the first end of the first secondary coil are dotted terminals; the first power supply access end of the power supply chip is coupled with the second end; the input end of the switch unit is coupled with the third end; the feedback end acquires a sampling signal of an output signal of the power supply output end; the output end of the switch unit is coupled with the power supply output end; at least one energy storage filter circuit is coupled between the power supply output end and the first grounding end; a positive electrode of a voltage stabilizing diode in the protection circuit is coupled to a first grounding end through a first resistor, and a negative electrode of the voltage stabilizing diode is coupled to a power supply output end. Through the series connection structure of the voltage stabilizing diode and the first resistor, accurate clamping of the voltage of the power supply output end is achieved, extra power consumption caused by too high no-load voltage is effectively restrained, and the working efficiency and the energy utilization rate of the power supply in the no-load state are remarkably improved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of power supply circuits, and in particular to a no-load control switching power supply circuit and a circuit breaker based on primary-side feedback. Background Art

[0002] At present, switching power supply technology has been widely used in many electronic devices, especially the switching power supply based on primary side feedback, which is popular due to its compact structure and flexible control. This type of power supply circuit can achieve precise control of the output voltage through the primary side feedback mechanism, and can maintain the stability and high efficiency of the power supply performance even when the load is no-load or light-loaded.

[0003] However, under no-load or light-load conditions, the primary-side feedback switching power supply often faces the problem of high no-load voltage, which will lead to unnecessary increase in power consumption, affect power efficiency, and may accelerate the aging of internal components of the power supply and reduce its service life.

[0004] In traditional solutions, a large resistor (dummy load), such as 4.7kΩ, is usually connected in parallel to the output end to simulate the actual load to maintain the stability of the output voltage. However, this will result in a no-load power consumption of about 0.03W, which is obviously not ideal for modern electronic devices that pursue low standby power consumption. Summary of the invention

[0005] In view of the above-mentioned shortcomings of the related art, the purpose of the present disclosure is to provide a no-load control switching power supply circuit and a circuit breaker based on primary side feedback to solve the problems in the related art.

[0006] A first aspect of the present disclosure provides a no-load control switching power supply circuit based on primary side feedback, which includes:

[0007] An input circuit for coupling an AC power source;

[0008] A transformer, the transformer comprising a primary coil and a first secondary coil;

[0009] The primary coil comprises a first end and a second end, and the output end of the input circuit is coupled to the first end through a rectifying and filtering unit;

[0010] The first secondary coil comprises a third end and a fourth end, and the third end and the first end are the same end;

[0011] A power chip, the power chip comprising a first power access terminal and a feedback terminal;

[0012] The first power supply access terminal is coupled to the second terminal;

[0013] a switch unit, wherein an input terminal of the switch unit is coupled to the third terminal;

[0014] An output unit, the output unit comprising a power supply output terminal and a first ground terminal;

[0015] The feedback end is coupled to the transformer or the power supply output end to obtain a sampling signal of an output signal of the power supply output end;

[0016] The fourth terminal is coupled to the first ground terminal;

[0017] The output end of the switch unit is coupled to the power supply output end;

[0018] At least one energy storage filter circuit is coupled between the power supply output terminal and the first ground terminal;

[0019] A protection circuit, the protection circuit comprising a voltage stabilizing diode and a first resistor;

[0020] The anode of the voltage-stabilizing diode is coupled to the first ground terminal through the first resistor, and the cathode of the voltage-stabilizing diode is coupled to the power supply output terminal.

[0021] In an embodiment of the first aspect, a resistance value of the first resistor is in one of the following ranges: 300 ohms to 400 ohms, 400 ohms to 500 ohms, 500 ohms to 600 ohms, 600 ohms to 700 ohms, 700 ohms to 800 ohms, 800 ohms to 900 ohms or 900 ohms to 1000 ohms.

[0022] In an embodiment of the first aspect, the transformer further comprises a second secondary coil;

[0023] The second secondary coil comprises a fifth end and a sixth end, wherein the fifth end is a same-name end as the first end and the third end;

[0024] The fifth terminal is coupled to the feedback terminal via a sampling circuit;

[0025] The power chip also includes a first power supply input terminal;

[0026] The fifth terminal is coupled to the first power supply input terminal via a power supply line.

[0027] In an embodiment of the first aspect, the sampling circuit includes:

[0028] a second resistor, one end of the second resistor being coupled to the fifth end, and the other end of the second resistor being coupled to the feedback end;

[0029] a third resistor, the third resistor being connected in parallel with the second resistor;

[0030] a fourth resistor, one end of the fourth resistor being coupled to the other end of the second resistor, and the other end of the fourth resistor being grounded;

[0031] A first capacitor is connected in parallel with the fourth resistor.

[0032] In an embodiment of the first aspect, the power supply circuit comprises:

[0033] a first diode, wherein an anode of the first diode is coupled to the fifth terminal, and a cathode of the first diode is coupled to the first power supply input terminal via a fifth resistor;

[0034] A second capacitor, one end of the second capacitor is coupled to the first power supply input end, and the other end of the second capacitor is grounded.

[0035] In an embodiment of the first aspect, an RCD absorption circuit is further provided between the rectification and filtering unit and the primary coil, and the RCD absorption circuit includes:

[0036] a second diode, wherein an anode of the second diode is coupled to the first power supply access terminal;

[0037] a sixth resistor, one end of the sixth resistor being coupled to the cathode of the second diode, and the other end of the sixth resistor being coupled to the second end via a seventh resistor;

[0038] an eighth resistor, the eighth resistor being connected in parallel with the sixth resistor;

[0039] A third capacitor is connected in parallel with the eighth resistor.

[0040] In an embodiment of the first aspect, the power chip further includes an overcurrent detection terminal, and the overcurrent detection terminal is grounded through an overcurrent detection circuit;

[0041] Then the overcurrent detection circuit comprises:

[0042] a ninth resistor, one end of which is coupled to the overcurrent detection terminal, and the other end of which is grounded;

[0043] A tenth resistor is connected in parallel with the ninth resistor.

[0044] In an embodiment of the first aspect, the switch unit includes:

[0045] a third diode, wherein an anode of the third diode is coupled to the third end, and a cathode of the third diode is coupled to the power supply output end;

[0046] An eleventh resistor, one end of the eleventh resistor is coupled to the anode of the third diode, and the other end of the eleventh resistor is coupled to the cathode of the third diode via a fourth capacitor.

[0047] In an embodiment of the first aspect, the energy storage filter circuit includes:

[0048] a fifth capacitor, one end of the fifth capacitor being coupled to the power supply output end, and the other end of the fifth capacitor being grounded;

[0049] a sixth capacitor, the sixth capacitor being connected in parallel with the fifth capacitor;

[0050] A seventh capacitor, one end of the seventh capacitor is coupled to the second end, and the other end of the seventh capacitor is grounded.

[0051] A second aspect of the present disclosure provides a circuit breaker, comprising a no-load control switch power supply circuit as described in any one of the above.

[0052] Beneficial effects of the present disclosure: The present disclosure realizes precise clamping of the voltage at the power supply output end through the series structure of the voltage-stabilizing diode and the first resistor in the protection circuit, effectively suppresses the additional power consumption caused by the excessive no-load voltage, thereby significantly improving the working efficiency and energy utilization of the power supply in the no-load state. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 A circuit schematic diagram of a no-load control switching power supply circuit based on primary side feedback in one embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0054] The following is an explanation of the embodiments of the present disclosure by specific examples, and those skilled in the art can easily understand other advantages and effects of the present disclosure from the information disclosed by the present disclosure. The present disclosure can also be implemented or applied through other different specific embodiments, and the details in the present disclosure can also be modified or changed in various ways according to different viewpoints and application modules without departing from the spirit of the present disclosure. It should be noted that the embodiments in the present disclosure and the features in the embodiments can be combined with each other without conflict.

[0055] The following is a detailed description of the embodiments of the present disclosure with reference to the accompanying drawings so that those skilled in the art can easily implement the present disclosure. The present disclosure can be embodied in many different forms and is not limited to the embodiments described herein.

[0056] In the representations of the present disclosure, the reference terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" and the like mean that the specific features, structures, materials or characteristics represented in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. Moreover, the specific features, structures, materials or characteristics represented may be combined in any one or a group of embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples represented in the present disclosure and the features of different embodiments or examples, unless they are mutually contradictory.

[0057] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the representation of the present disclosure, "a group" means two or more, unless otherwise clearly and specifically defined.

[0058] In order to clearly describe the present disclosure, components not related to the description are omitted, and the same reference numerals are given to the same or similar components throughout the specification.

[0059] Throughout the specification, when a device is said to be "connected" or "coupled" to another device, this includes not only the case of "direct connection" but also the case of "indirect connection" by placing other elements therebetween. In addition, when a device is said to "include" a certain constituent element, unless otherwise stated, it does not exclude other constituent elements, but means that other constituent elements may be included.

[0060] Although the terms first, second, etc. are used to represent various elements in this article in some examples, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, the first interface and the second interface, etc. are represented. Moreover, as used in this article, the singular forms "one", "one" and "the" are intended to also include plural forms, unless there is an opposite indication in the context. It should be further understood that the terms "comprising" and "including" indicate that there are the described features, steps, operations, elements, modules, projects, kinds, and / or groups, but do not exclude the existence, occurrence or addition of one or a group of other features, steps, operations, elements, modules, projects, kinds, and / or groups. The terms "or" and "and / or" used herein are interpreted as inclusive, or mean any one or any combination. Therefore, "A, B or C" or "A, B and / or C" means "any of the following: A; B; C; A and B; A and C; B and C; A, B and C". Only when the combination of elements, functions, steps or operations is inherently mutually exclusive in some way, will there be an exception to this definition.

[0061] The technical terms used herein are only used to refer to specific embodiments and are not intended to limit the present disclosure. The singular form used herein also includes the plural form unless the sentence clearly indicates the contrary meaning. The meaning of "including" used in the specification is to specify specific characteristics, regions, integers, steps, operations, elements and / or components, and does not exclude the existence or addition of other characteristics, regions, integers, steps, operations, elements and / or components.

[0062] Although not defined differently, all terms, including technical and scientific terms used herein, have the same meaning as those generally understood by those skilled in the art to which the present disclosure belongs. Terms defined in commonly used dictionaries are additionally interpreted as having meanings consistent with relevant technical literature and the message of the present disclosure, and shall not be overly interpreted as ideal or very formal meanings unless defined.

[0063] like Figure 1 As shown, a circuit principle schematic diagram of a no-load control switch power supply circuit in an embodiment of the present disclosure is shown.

[0064] like Figure 1 As shown, the no-load control switching power supply circuit includes: an input circuit, a transformer T, a rectifier and filter unit, a power chip, a switch unit, an output unit, an energy storage filter circuit and a protection circuit.

[0065] The input circuit is used to couple an AC power source;

[0066] The transformer T comprises: a primary coil and a first secondary coil;

[0067] The primary coil includes a first end 1 and a second end 2, and the output end of the input circuit is coupled to the first end 1 through the rectifying and filtering unit;

[0068] The first secondary coil comprises a third end 3 and a fourth end 4, wherein the third end 3 and the first end 1 are the same end;

[0069] The power chip comprises: a first power access terminal SW and a feedback terminal FB;

[0070] The first power supply input terminal SW is coupled to the second terminal 2;

[0071] The input terminal of the switch unit is coupled to the third terminal 3;

[0072] The output unit includes a power supply output terminal f0 and a first ground terminal GND1;

[0073] The feedback terminal FB is coupled to the transformer T or the power supply output terminal f0 to obtain a sampling signal of the output signal of the power supply output terminal f0;

[0074] The fourth terminal 4 is coupled to the first ground terminal GND1;

[0075] The output end of the switch unit is coupled to the power supply output end f0;

[0076] At least one energy storage filter circuit is coupled between the power supply output terminal f0 and the first ground terminal GND1;

[0077] The protection circuit includes a voltage stabilizing diode D1 and a first resistor R1;

[0078] An anode of the Zener diode D1 is coupled to the first ground terminal GND1 through the first resistor R1 , and a cathode of the Zener diode D1 is coupled to the power output terminal f0 .

[0079] Specifically, with respect to the related art, under no-load or light-load conditions, the primary-side feedback switching power supply often faces the problem of high no-load voltage, which will lead to unnecessary increase in power consumption, affect power supply efficiency, and may accelerate the aging of internal components of the power supply and reduce its service life.

[0080] In traditional solutions, a large resistor (dummy load) is usually connected in parallel to the output end, usually in the thousands of ohms level, such as 4.7kΩ, to simulate the actual load to maintain the stability of the output voltage. However, this will result in a no-load power consumption of about 0.03W, which is obviously not ideal for modern electronic devices that pursue low standby power consumption.

[0081] exist Figure 1 In the embodiment, a switching power supply circuit is shown which mainly includes an input circuit, a transformer T, a rectifier filter unit, a power chip, a switch unit, an output unit, an energy storage filter circuit and a protection circuit.

[0082] First, the input circuit is coupled with the external AC power supply, and the obtained AC voltage is rectified through the rectifier and filter unit to obtain a DC voltage output. The output end of the rectifier and filter unit is connected to the first end 1 of the primary coil of the transformer T, and the second end 2 of the primary coil is coupled to the first power access terminal SW of the power chip, so that the power chip can obtain working power from the rectified DC power.

[0083] Optional, such as Figure 1As shown, the input unit includes a live wire L and a neutral wire N. One end of the live wire L is connected to an external power supply, and the other end of the live wire L is coupled to the rectifier filter unit after passing through a fuse F1. The fuse F1 can limit the rising speed of the current through its own impedance, buy time for the subsequent protection devices (such as circuit breakers, fuses, etc.) to act, and avoid the current being too large in an instant to cause serious damage to the circuit. Adjustable resistor RV1, one end of the adjustable resistor RV1 is connected to the live wire L through the fuse F1, and the other end is connected to the neutral wire N.

[0084] One end of the neutral line N is grounded to ensure that the circuit has a good reference potential and is also part of the current loop. The other end of the neutral line N is connected to the input end of the rectifier and filter unit.

[0085] Optional, such as Figure 1 As shown, the rectifying and filtering unit includes a rectifying bridge A and a filtering circuit, and the filtering circuit includes a first inductor L1, a twelfth resistor R12, an eighth capacitor C8 and a ninth capacitor C9;

[0086] The input end of the rectifier bridge A is connected to the live wire L and the neutral wire N, and the AC power input by the live wire L and the neutral wire N is rectified to output DC power. The output end of the rectifier bridge A is connected to the first inductor L1, and the first inductor L1 has the functions of energy storage, filtering and anti-interference. The first inductor L1 can limit the rate of change of the current, smooth the current waveform, and absorb some high-frequency harmonics.

[0087] The twelfth resistor R12 is connected in parallel with the first inductor L1 in the circuit. The twelfth resistor R12 provides a certain damping to the current, which helps to stabilize the working state of the rectifier bridge A and suppress possible oscillation. In addition, the twelfth resistor R12 can also form an RL filter network with the first inductor L1 to further improve the current waveform.

[0088] In some embodiments, an eighth capacitor C8 and a ninth capacitor C9 are connected in parallel between the twelfth resistor R12 and the ground terminal, which further enhances the ability to suppress low-frequency AC components and ensures that the output current has small ripple and high stability.

[0089] The transformer T also includes a first secondary coil, and the third end 3 of the first secondary coil is the same as the first end 1 of the primary coil to achieve magnetic coupling. The input end of the switch unit is connected to the third end 3 of the first secondary coil to control the switching state of the power supply.

[0090] The output unit is provided with a power supply output terminal f0 and a first ground terminal GND1. The feedback terminal FB of the power chip obtains a sampling signal of the output signal from the transformer T or the power supply output terminal f0 by coupling to realize closed-loop control. The fourth terminal 4 of the first secondary coil is directly connected to the first ground terminal GND1 to form a complete current loop.

[0091] The output end of the switch unit is directly connected to the power supply output end f0 to provide a stable voltage output for the load. At least one energy storage filter circuit is provided between the power supply output end f0 and the first ground terminal GND1 to store energy and filter voltage fluctuations to ensure the stability of the output voltage.

[0092] Furthermore, the protection circuit in this embodiment adopts an improved solution. The protection circuit includes a voltage stabilizing diode D1 and a first resistor R1, the positive electrode of the voltage stabilizing diode D1 is grounded through the first resistor R1, and the negative electrode is coupled to the power supply output terminal f0. In view of the problem of high no-load voltage when the primary feedback switching power supply is unloaded or lightly loaded, the voltage of the power supply output terminal f0 is clamped at a preset threshold value by the cooperation of the voltage stabilizing diode D1 and the resistor, thereby effectively reducing the no-load power consumption. Compared with the traditional solution, this embodiment abandons the practice of connecting a large resistor (such as 4.7kΩ) in parallel to the output end to simulate the load. Although the traditional solution can temporarily maintain the output voltage stable, it will bring 0.03W of additional no-load power consumption. In this embodiment, through the optimized design, even in the no-load state, the protection circuit formed by the voltage stabilizing diode D1 and the first resistor R1 in series can significantly reduce the no-load power consumption, which meets the high standard requirements of modern electronic equipment for low standby power consumption, while improving the power supply efficiency and extending the service life of the power supply.

[0093] Optionally, the resistance value of the first resistor R1 is in one of the following ranges: 300 ohms to 400 ohms, 400 ohms to 500 ohms, 500 ohms to 600 ohms, 600 ohms to 700 ohms, 700 ohms to 800 ohms, 800 ohms to 900 ohms or 900 ohms to 1000 ohms.

[0094] Specifically, in the above embodiment, the resistance value of the first resistor R1 is flexible and can be selected within the following series of preset ranges according to different application scenarios and performance requirements: if the range of 300 ohms to 400 ohms is selected, this resistance value will enable the protection circuit to achieve a more sensitive and efficient voltage clamping effect under no-load or light-load conditions, while maintaining lower resistance power consumption.

[0095] If you choose a resistance value in the range of 400 ohms to 500 ohms, 500 ohms to 600 ohms, 600 ohms to 700 ohms, 700 ohms to 800 ohms, 800 ohms to 900 ohms or 900 ohms to 1000 ohms, you can adapt to different load conditions and voltage stability requirements. As the resistance value increases, although the power consumption of the resistor itself will be further reduced, it may also affect the speed and effect of voltage clamping, and the overall performance balance of the system needs to be considered comprehensively.

[0096] For example, in a specific embodiment, when the resistance value of the first resistor R1 is 400 ohms, the no-load voltage of the primary feedback will be high, and generally a resistor (dummy load) R=4.7k will be connected to the output end, and the power consumption is about 0.03 W. Since the voltage zener diode D1 is connected in series with the first resistor R1, the power consumption of the resistor after the first resistor R1 of 400 ohms is connected in series is 1*1 / 400=0.0025 W, which is an order of magnitude different from 0.03 W, which can reduce the no-load power consumption and ensure that the voltage of the power supply output terminal f0 can be effectively clamped while reducing the no-load power consumption. And by working in conjunction with the voltage zener diode D1, unnecessary power consumption can be reduced, power efficiency can be improved, and the service life of the internal components of the power supply can be extended.

[0097] Optional, such as Figure 1 As shown, the transformer T also includes a second secondary coil;

[0098] The second secondary coil comprises a fifth end 5 and a sixth end 6, wherein the fifth end 5 is a same end as the first end 1 and the third end 3;

[0099] The fifth terminal 5 is coupled to the feedback terminal FB via a sampling circuit;

[0100] The power chip also includes a first power supply input terminal VDD;

[0101] The fifth terminal 5 is coupled to the first power input terminal VDD via a power supply line.

[0102] Specifically, in the above embodiment, the transformer T includes a second secondary coil in addition to the primary coil and the first secondary coil. The second secondary coil has a fifth end 5 and a sixth end 6, wherein the fifth end 5 and the first end 1 of the primary coil and the third end 3 of the first secondary coil are all the same-named ends, which means that there is an electromagnetic coupling relationship between the second secondary coil and the primary coil and the first secondary coil.

[0103] Therefore, when current flows through the primary coil, the primary coil is in an energy storage state, and at this time, the energy storage filter circuit provides energy to the output unit;

[0104] When no current flows through the primary coil, the first secondary coil and the second secondary coil obtain energy from the primary coil and are in an energy release state.

[0105] Optionally, in order to achieve accurate feedback control of the power chip, the fifth terminal 5 of the second secondary coil is coupled to the feedback terminal FB of the power chip through a sampling circuit. The sampling circuit is responsible for collecting the voltage signal of the second secondary coil and converting it into a signal suitable for processing by the power chip, so that the power chip can automatically regulate the output voltage of the f0 terminal according to the sampling signal of the feedback terminal to ensure the stability and accuracy of the output voltage.

[0106] Specifically, the power chip adjusts the on-off frequency between the first power access terminal SW and the second ground terminal GND2 within the cycle according to the signal of the feedback terminal. It can be understood that when the first power access terminal SW and the second ground terminal GND2 are turned on, the current flowing from the second end to the first end in the primary coil obtains energy storage, and due to the unidirectional rectification effect of V1 and V3 and the principle of the same-name terminal, no current flows through the first secondary coil and the second secondary coil at this time; and, when the first power access terminal SW and the second ground terminal GND2 are disconnected, the primary coil does not store energy, the first secondary coil and the second secondary coil discharge, the first secondary coil supplies power to the load connected to f0 and charges at least one energy storage filter capacitor, and the second secondary coil charges C2 and supplies power to VDD. It can be seen that when the power chip determines that the f0 voltage is lower than the standard output value based on the sampling signal of FB, the conduction frequency can be increased to pull up f0 to the standard value; and when it determines that the f0 voltage rises above the standard output value based on the sampling signal of FB, the conduction frequency can be reduced to reduce f0 to the standard value, thereby realizing automatic voltage regulation adjustment of the output voltage at the adaptive f0 end.

[0107] Optionally, considering the power supply requirements of the power chip itself, a first power supply input terminal VDD is also provided. To meet the working requirements of the power chip, the fifth end 5 of the second secondary coil is connected to the first power supply input terminal VDD of the power chip through a power supply line to provide a stable power supply voltage.

[0108] Optional, such as Figure 1 As shown, the sampling circuit includes:

[0109] a second resistor R2, one end of the second resistor R2 is coupled to the fifth end 5, and the other end of the second resistor R2 is coupled to the feedback end FB;

[0110] A third resistor R3, the third resistor R3 is connected in parallel with the second resistor R2;

[0111] a fourth resistor R4, one end of the fourth resistor R4 is coupled to the other end of the second resistor R2, and the other end of the fourth resistor R4 is grounded;

[0112] A first capacitor C1 is connected in parallel with the fourth resistor R4.

[0113] Specifically, in the above embodiment, the sampling circuit is used to obtain and process the voltage signal from the fifth terminal 5 of the second secondary coil of the transformer T, so as to achieve accurate sampling of the power supply output voltage and feedback to the feedback terminal FB of the power supply chip.

[0114] Optionally, the sampling circuit is composed of a second resistor R2, a third resistor R3, a fourth resistor R4 and a first capacitor C1. One end of the second resistor R2 is directly coupled to the fifth end 5 of the second secondary coil of the transformer T, and is used to extract a voltage signal from the fifth end 5. The other end is coupled to the feedback end FB of the power chip, and the voltage signal is sent to the feedback end FB after being divided by the second resistor R2, so that the power chip can perform voltage sampling and control.

[0115] The third resistor R3 is connected in parallel with the second resistor R2 to form a voltage divider network. In actual operation, the parallel structure of the third resistor R3 and the second resistor R2 can flexibly adjust the size of the sampling voltage and help improve the quality and stability of the sampling signal. One end of the fourth resistor R4 is coupled to the other end of the second resistor R2 to form a part of the series circuit. The other end of the fourth resistor R4 is directly grounded, and the voltage in the sampling circuit is further processed through the fourth resistor R4, and a path to the ground is provided to facilitate the closure of the current loop and the discharge of noise.

[0116] The first capacitor C1 is connected in parallel with the fourth resistor R4 to form an RC filter circuit. The presence of the first capacitor C1 can filter out high-frequency noise and fluctuations in the sampled signal, ensuring that the voltage signal fed back to the power chip is smoother and more stable. At the same time, the capacitor can provide transient response to ensure that the power chip obtains timely and accurate voltage feedback information when the load changes.

[0117] Optional, such as Figure 1 As shown, the power supply circuit includes:

[0118] a first diode V1, wherein an anode of the first diode V1 is coupled to the fifth terminal 5, and a cathode of the first diode V1 is coupled to the first power supply input terminal VDD via a fifth resistor R5;

[0119] A second capacitor C2, one end of the second capacitor C2 is coupled to the first power supply input terminal VDD, and the other end of the second capacitor C2 is grounded.

[0120] Specifically, in the above embodiment, the power supply circuit is used to provide a stable power supply for the power chip. The first diode V1 is configured to be forward-conducted, and its anode is directly coupled to the fifth terminal 5 of the second secondary coil of the transformer T. When the voltage induced by the second secondary coil is sufficient to turn on the first diode V1, the current can flow to the first power supply input terminal VDD of the power chip through the first diode V1. The first diode V1 plays a role of rectification here.

[0121] The cathode of the first diode V1 is connected via the fifth resistor R5. The fifth resistor R5 plays the role of current limiting and voltage dividing in the circuit. It can limit the current passing through the first diode V1 to prevent the instantaneous large current from impacting the power chip. At the same time, it can also change the voltage value applied to the power chip according to its resistance value to meet the appropriate voltage level required for the chip to work.

[0122] One end of the second capacitor C2 is directly coupled to the first power supply input terminal VDD of the power chip, and the other end is grounded. As a filter capacitor at the power input terminal, the second capacitor C2 can absorb transient noise and ripple in the power supply voltage, providing a more stable power supply environment for the power chip. At the same time, when the power supply voltage drops briefly, the capacitor can quickly replenish the current through the stored energy, maintain the stability of the power supply voltage, and prevent the power chip from abnormalities due to voltage fluctuations.

[0123] Optional, such as Figure 1 As shown, an RCD absorption circuit is also provided between the rectification and filtering unit and the primary coil, and the RCD absorption circuit includes:

[0124] a second diode V2, wherein an anode of the second diode V2 is coupled to the first power supply access terminal SW;

[0125] a sixth resistor R6, one end of the sixth resistor R6 is coupled to the cathode of the second diode V2, and the other end of the sixth resistor R6 is coupled to the second end 2 via a seventh resistor R7;

[0126] an eighth resistor R8, the eighth resistor R8 being connected in parallel with the sixth resistor R6;

[0127] A third capacitor C3 is connected in parallel with the eighth resistor R8.

[0128] Optional, such as Figure 1 As shown, an RCD absorption circuit is further provided between the rectifying and filtering unit and the primary coil, and the RCD absorption circuit includes: a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a third capacitor C3 and a second diode V2;

[0129] The RCD absorption circuit further improves the voltage and current waveforms during the rectification process, reduces electromagnetic interference, and protects the rectification and filtering unit and subsequent equipment from surge shocks.

[0130] One end of the seventh resistor R7 is connected to the output end of the rectifying and filtering unit, and the other end is coupled to the second end 2 of the primary coil;

[0131] The seventh resistor R7 and the eighth resistor R8 are connected in parallel, and the seventh resistor R7 and the eighth resistor R8 together form an impedance network to further stabilize and protect the output of the rectification and filtering unit.

[0132] The third capacitor C3 is connected in parallel with the eighth resistor R8, and the third capacitor C3 can absorb the voltage spikes and current pulses generated during the rectification process, smooth the voltage waveform, and reduce electromagnetic interference. At the same time, the charging and discharging characteristics of the capacitor help maintain the continuity of the current and avoid voltage fluctuations caused by current mutations.

[0133] The anode of the second diode V2 is connected to the first power access terminal SW of the power chip, and the cathode of the second diode V2 is connected to the second terminal 2 through the sixth resistor R6.

[0134] The second resistor R2 plays a unidirectional conductive role, allowing only the current from the first terminal 1 to flow to the sixth resistor R6, preventing the reverse current from passing. This design can prevent voltage spikes and current shocks caused by parasitic inductance effects during the shutdown or reverse recovery of the rectifier and filter unit, protecting the rectifier and filter unit and subsequent equipment from damage.

[0135] Optional, such as Figure 1 As shown, the power chip also includes an overcurrent detection terminal, and the overcurrent detection terminal is grounded through an overcurrent detection circuit;

[0136] Then the overcurrent detection circuit comprises:

[0137] a ninth resistor R9, one end of the ninth resistor R9 is coupled to the over-current detection end, and the other end of the ninth resistor R9 is grounded;

[0138] The tenth resistor R10 is connected in parallel with the ninth resistor R9.

[0139] Optionally, the power chip also includes an overcurrent detection terminal, which is grounded through an overcurrent detection circuit to facilitate real-time monitoring of the power output current, prevent the occurrence of overcurrent conditions, and protect the power system and load from damage.

[0140] One end of the ninth resistor R9 is directly coupled to the overcurrent detection end of the power chip. When the power output current is too large, the overcurrent detection end will sense an abnormal current signal. The ninth resistor R9 is used as a current detection resistor, and the voltage drop across the resistor R9 is measured to indirectly reflect the current through the power chip.

[0141] The tenth resistor R10 is connected in parallel with the ninth resistor R9. When an overcurrent condition occurs, the tenth resistor R10 and the ninth resistor R9 share the voltage drop, thereby triggering the overcurrent protection mechanism at a lower current increment to prevent excessive current from continuously passing through the power supply system.

[0142] When the power supply output current exceeds the preset threshold, the parallel circuit formed by the ninth resistor R9 and the tenth resistor R10 will cause the voltage at the overcurrent detection end to rise. The power chip detects this voltage change, identifies the overcurrent condition, and takes quick action, such as turning off the switching element or adjusting the working mode, to prevent the overcurrent from damaging the power supply system and load, thereby ensuring the safe and stable operation of the entire system.

[0143] Optional, such as Figure 1 As shown, the switch unit includes:

[0144] a third diode V3, wherein an anode of the third diode V3 is coupled to the third terminal 3, and a cathode of the third diode V3 is coupled to the power supply output terminal f0;

[0145] An eleventh resistor R11 , one end of the eleventh resistor R11 is coupled to the anode of the third diode V3 , and the other end of the eleventh resistor R11 is coupled to the cathode of the third diode V3 via a fourth capacitor C4 .

[0146] Optionally, the third diode V3 plays a unidirectional conductive role. When current passes through the primary coil, the third end 3 of the first secondary coil is the negative pole and the fourth end 4 is the positive pole, so the third diode V3 is not conducting. Therefore, the external load is provided with electrical energy by the energy storage filter circuit, and vice versa.

[0147] The anode of the third diode V3 is coupled to the third terminal 3 of the first secondary coil of the transformer T, and is used to sense and conduct energy from the transformer T. The cathode of the third diode V3 is coupled to the power supply output terminal f0 of the power supply circuit, ensuring that the rectified and converted energy can be smoothly transmitted to the load.

[0148] The eleventh resistor R11 is arranged between the anode of the third diode V3 and the power supply output terminal f0, wherein one end of the eleventh resistor R11 is directly connected to the anode of the third diode V3. The function of the eleventh resistor R11 here is to limit the current passing through the third diode V3 to prevent the device from being damaged due to excessive current, and the switching speed and loss of the switch unit can be adjusted by adjusting its resistance value.

[0149] A fourth capacitor C4 is connected in series between the eleventh resistor R11 and the cathode of the third diode V3. One end of the fourth capacitor C4 is coupled to the other end of the eleventh resistor R11, and the other end is coupled to the cathode of the third diode V3, i.e., the power supply output terminal f0. The fourth capacitor C4 mainly plays the role of filtering and smoothing voltage fluctuations in the switch unit, absorbing high-frequency noise and transient spikes generated by switch switching, ensuring that the voltage of the power supply output terminal f0 is more stable, and also helps to improve the electromagnetic compatibility (EMC) performance of the power supply.

[0150] Optional, such as Figure 1 As shown, the at least one energy storage filter circuit comprises:

[0151] a fifth capacitor C5, one end of the fifth capacitor C5 is coupled to the power supply output terminal f0, and the other end of the fifth capacitor C5 is grounded;

[0152] a sixth capacitor C6, wherein the sixth capacitor C6 is connected in parallel with the fifth capacitor C5;

[0153] A seventh capacitor C7, one end of the seventh capacitor C7 is coupled to the second end 2, and the other end of the seventh capacitor C7 is grounded.

[0154] Specifically, in the above embodiment, the energy storage filter circuit adopts a multi-capacitor structure, aiming to improve the stability of the power output and reduce the voltage ripple, and specifically includes a fifth capacitor C5, a sixth capacitor C6 and a seventh capacitor C7.

[0155] One end of the fifth capacitor C5 is directly coupled to the power supply output terminal f0 of the power supply circuit, which is used to store and release electric energy to maintain the stability of the output voltage. The other end is grounded to form a basic filter capacitor structure, which effectively filters out the high-frequency noise and ripple in the output voltage. The sixth capacitor C6 is connected in parallel with the fifth capacitor C5, and the two together constitute a parallel filter capacitor group. By connecting in parallel, the sixth capacitor C6 further enhances the energy storage filtering capability, improves the transient response speed of the power supply output voltage, effectively suppresses the voltage drop when the load changes suddenly, and ensures the smoothness and stability of the output voltage. One end of the seventh capacitor C7 is coupled to the second end 2 of the primary coil of the transformer T, that is, connected to the rectified DC voltage part, and its main function is to filter the rectified DC voltage, further reducing the ripple and noise at the power input end. The other end of the seventh capacitor C7 is also grounded to form a filtering link for the input DC voltage, ensuring that the power chip and subsequent circuits obtain a purer and more stable voltage supply.

[0156] In yet another embodiment of the present disclosure, a circuit breaker is provided, comprising the no-load control switch power supply circuit as described in any one of the above.

[0157] The above embodiments are merely illustrative of the principles and effects of the present disclosure, and are not intended to limit the present disclosure. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present disclosure. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed in the present disclosure shall still be covered by the protection scope of the present disclosure.

Claims

1. A no-load control switching power supply circuit based on primary side feedback, characterized in that: include: An input circuit for coupling an AC power source; A transformer, the transformer comprising a primary coil and a first secondary coil; The primary coil comprises a first end and a second end, and the output end of the input circuit is coupled to the first end through a rectifying and filtering unit; The first secondary coil comprises a third end and a fourth end, and the third end and the first end are the same end; A power chip, the power chip comprising a first power access terminal and a feedback terminal; The first power supply access terminal is coupled to the second terminal; a switch unit, wherein an input terminal of the switch unit is coupled to the third terminal; An output unit, the output unit comprising a power supply output terminal and a first ground terminal; The feedback end is coupled to the transformer or the power supply output end to obtain a sampling signal of an output signal of the power supply output end; The fourth terminal is coupled to the first ground terminal; The output end of the switch unit is coupled to the power supply output end; At least one energy storage filter circuit is coupled between the power supply output terminal and the first ground terminal; A protection circuit, the protection circuit comprising a voltage stabilizing diode and a first resistor; The anode of the voltage-stabilizing diode is coupled to the first ground terminal through the first resistor, and the cathode of the voltage-stabilizing diode is coupled to the power supply output terminal.

2. The no-load control switching power supply circuit according to claim 1, characterized in that: The resistance value of the first resistor is in one of the following ranges: 300 ohms to 400 ohms, 400 ohms to 500 ohms, 500 ohms to 600 ohms, 600 ohms to 700 ohms, 700 ohms to 800 ohms, 800 ohms to 900 ohms or 900 ohms to 1000 ohms.

3. The no-load control switching power supply circuit according to claim 1, characterized in that: The transformer also includes a second secondary coil; The second secondary coil comprises a fifth end and a sixth end, wherein the fifth end is a same-name end as the first end and the third end; The fifth terminal is coupled to the feedback terminal via a sampling circuit; The power chip also includes a first power supply input terminal; The fifth terminal is coupled to the first power supply input terminal via a power supply line.

4. The no-load control switching power supply circuit according to claim 3, characterized in that: The sampling circuit comprises: a second resistor, one end of the second resistor being coupled to the fifth end, and the other end of the second resistor being coupled to the feedback end; a third resistor, the third resistor being connected in parallel with the second resistor; a fourth resistor, one end of the fourth resistor being coupled to the other end of the second resistor, and the other end of the fourth resistor being grounded; A first capacitor is connected in parallel with the fourth resistor.

5. The no-load control switching power supply circuit according to claim 3, characterized in that: The power supply circuit comprises: a first diode, wherein an anode of the first diode is coupled to the fifth terminal, and a cathode of the first diode is coupled to the first power supply input terminal via a fifth resistor; A second capacitor, one end of the second capacitor is coupled to the first power supply input end, and the other end of the second capacitor is grounded.

6. The no-load control switching power supply circuit according to claim 1, characterized in that: An RCD absorption circuit is also provided between the rectification and filtering unit and the primary coil, and the RCD absorption circuit comprises: a second diode, wherein an anode of the second diode is coupled to the first power supply access terminal; a sixth resistor, one end of the sixth resistor being coupled to the cathode of the second diode, and the other end of the sixth resistor being coupled to the second end via a seventh resistor; an eighth resistor, the eighth resistor being connected in parallel with the sixth resistor; A third capacitor is connected in parallel with the eighth resistor.

7. The no-load control switching power supply circuit according to claim 1, characterized in that: The power chip also includes an overcurrent detection terminal, which is grounded through an overcurrent detection circuit; Then the overcurrent detection circuit comprises: a ninth resistor, one end of which is coupled to the overcurrent detection terminal, and the other end of which is grounded; A tenth resistor is connected in parallel with the ninth resistor.

8. The no-load control switching power supply circuit according to claim 1, characterized in that: The switch unit comprises: a third diode, wherein an anode of the third diode is coupled to the third end, and a cathode of the third diode is coupled to the power supply output end; An eleventh resistor, one end of the eleventh resistor is coupled to the anode of the third diode, and the other end of the eleventh resistor is coupled to the cathode of the third diode via a fourth capacitor.

9. The no-load control switching power supply circuit according to claim 1, characterized in that: The energy storage filter circuit comprises: a fifth capacitor, one end of which is coupled to the power supply output terminal, and the other end of which is grounded; a sixth capacitor, the sixth capacitor being connected in parallel with the fifth capacitor; A seventh capacitor, one end of the seventh capacitor is coupled to the second end, and the other end of the seventh capacitor is grounded.

10. A circuit breaker, characterized in that: It comprises a no-load control switching power supply circuit as described in any one of claims 1 to 9 above.

Images