Output circuit and switching power supply system using the same

Abstract

The present invention discloses an output circuit and a switching power supply system using the circuit, including a step-down circuit for realizing voltage transformation regulation and a switching capacitor voltage stabilizing circuit for realizing voltage stabilization control; the signal input end of the step-down circuit serves as the signal input end of the entire output circuit, the control end of the step-down circuit is electrically connected to the enable end of the switching capacitor voltage stabilizing circuit, the signal output end of the step-down circuit is electrically connected to the signal input end of the switching capacitor voltage stabilizing circuit and serves as the energy storage end of the entire output circuit, and the signal output end or the wire grounding end of the switching capacitor voltage stabilizing circuit serves as the signal input end of the entire output circuit. The output circuit proposed by the present invention has a simple and intuitive structure, ensures the use effect and improves reliability; applying the circuit in a switching power supply system can effectively optimize the system structure and reduce the manufacturing cost of the system.

Description

Technical Field

[0001] The present invention relates to an output circuit and a switching power supply using the circuit, and in particular to an output circuit with high reliability and capable of realizing voltage output in various forms and a switching power supply system using the circuit, belonging to the field of power semiconductor technology. Background Art

[0002] As the core component of modern power conversion technology and the structural basis of various electrical mechanisms and devices, the switching power supply system has been widely used in the fields of power, communication, transportation, and industrial control. In addition, in recent years, with the continuous development and improvement of electronic power technology and industrial manufacturing level, various types and functions of switching power supply systems have appeared one after another, greatly broadening the user's technical selection space.

[0003] Take the switch circuit system with negative voltage output function commonly seen in electrical mechanisms and devices as an example. Most of the common circuits of this type on the market currently use Buck-boost or Buck topology, and the system is composed of components such as rectifier elements, filter circuits, power capacitors, output capacitors, energy storage inductors, freewheeling diodes, feedback diodes, and control chips. According to different actual use requirements, the filter circuit can use a π-type filter circuit composed of a filter capacitor and a filter inductor, or a differential mode inductor or a common mode inductor; the rectifier element can use a rectifier diode or a rectifier bridge.

[0004] However, in the actual application of this type of circuit system, technicians have found that such a system structure is often affected by parasitic parameters in the circuit, resulting in unstable system parameters. In addition, the overall electromagnetic interference of the system is serious and the output ripple is large.

[0005] In addition, the existing circuit systems of this type use many components, have complex internal structures, and implement single functions, which not only makes the overall assembly cost of the system relatively high, but also greatly restricts the application of the circuit system in miniaturization. In addition, the switch circuit system is usually equipped with inductors, which can easily cause problems such as electromagnetic radiation and shielding, further affecting the normal use of the circuit system.

[0006] Because of the above-mentioned deficiencies in the prior art, how to propose an output circuit with high reliability and capable of realizing various forms of voltage output and a switching power supply system using the circuit on the basis of the prior art, while having a negative voltage output function and overcoming the above-mentioned problems, has become an urgent problem to be solved by technical personnel in the industry. Summary of the invention

[0007] In view of the above-mentioned defects in the prior art, the purpose of the present invention is to provide an output circuit with high reliability and capable of realizing various forms of voltage output and a switching power supply system using the circuit, as follows.

[0008] An output circuit includes a step-down circuit for realizing voltage transformation regulation and a switch capacitor voltage stabilizing circuit for realizing voltage stabilization control;

[0009] The step-down circuit is a chopper circuit, the switch capacitor voltage stabilizing circuit is a charge pump circuit, and the step-down circuit and the switch capacitor voltage stabilizing circuit are connected in series in sequence;

[0010] The signal input end of the step-down circuit serves as the signal input end of the entire output circuit, the control end of the step-down circuit is electrically connected to the enable end of the switched capacitor voltage stabilizing circuit, the signal output end of the step-down circuit is electrically connected to the signal input end of the switched capacitor voltage stabilizing circuit and serves as the energy storage end of the entire output circuit, and the signal output end or the wire grounding end of the switched capacitor voltage stabilizing circuit serves as the signal input end of the entire output circuit.

[0011] Preferably, the entire output circuit is a negative voltage output circuit;

[0012] At this time, the wire grounding end of the step-down circuit is electrically connected to the wire grounding end of the switching capacitor voltage stabilizing circuit and serves as the wire grounding end of the entire output circuit, and the signal output end of the switching capacitor voltage stabilizing circuit serves as the signal output end of the entire output circuit.

[0013] Preferably, the entire output circuit is a half-voltage output circuit;

[0014] At this time, the wire grounding end of the step-down circuit is electrically connected to the signal output end of the switching capacitor voltage stabilizing circuit and serves as the wire grounding end of the entire output circuit. The wire grounding end of the switching capacitor voltage stabilizing circuit serves as the signal output end of the entire output circuit.

[0015] Preferably, the entire output circuit is a multi-channel output circuit;

[0016] The wire grounding end of the step-down circuit is electrically connected to the signal output end of the switch capacitor voltage stabilizing circuit and serves as the wire grounding end of the entire output circuit. The wire grounding end of the switch capacitor voltage stabilizing circuit serves as the signal output end of the entire output circuit.

[0017] At this time, the entire output circuit also includes another switched capacitor voltage stabilizing circuit, the enable end of the other switched capacitor voltage stabilizing circuit is electrically connected to the control end of the step-down circuit, the signal input end of the other switched capacitor voltage stabilizing circuit is electrically connected to the signal output end of the step-down circuit, and they jointly serve as the energy storage end of the entire output circuit, the wire grounding end of the other switched capacitor voltage stabilizing circuit is electrically connected to the wire grounding end of the step-down circuit, and they jointly serve as the wire grounding end of the entire output circuit, and the signal output end of the other switched capacitor voltage stabilizing circuit serves as another signal output end of the entire output circuit.

[0018] Preferably, the step-down circuit includes a transistor, an input voltage-dividing upper resistor, an input voltage-dividing lower resistor, a first logic controller, a driver, a first output voltage-dividing upper resistor, and a first output voltage-dividing lower resistor;

[0019] The drain of the transistor is electrically connected to one end of the input voltage-dividing upper resistor, serving as the signal input end of the entire step-down circuit; the other end of the input voltage-dividing upper resistor is electrically connected to one end of the input voltage-dividing lower resistor, and both are electrically connected to the first input end of the first logic controller, transmitting the input voltage-dividing signal to the first logic controller; the first output end of the first logic controller is electrically connected to the input end of the driver, and the output end of the driver is electrically connected to the gate of the transistor; the second output end of the first logic controller serves as the control end of the entire step-down circuit; the source of the transistor is electrically connected to the first output voltage-dividing upper resistor, serving as the signal output end of the entire step-down circuit; the other end of the first output voltage-dividing upper resistor is electrically connected to one end of the first output voltage-dividing lower resistor, and both are electrically connected to the second input end of the first logic controller, transmitting the output voltage-dividing signal to the first logic controller; the other end of the input voltage-dividing lower resistor is electrically connected to the other end of the first output voltage-dividing lower resistor, serving as the wire grounding end of the entire step-down circuit.

[0020] Preferably, the switch capacitor voltage stabilization circuit comprises a second logic controller, a first switch transistor, a second switch transistor, a third switch transistor, a fourth switch transistor, a second output voltage divider upper resistor and a second output voltage divider lower resistor;

[0021] One end of the first switch transistor serves as a signal input end of the entire switch capacitor voltage stabilization circuit, the other end of the first switch transistor is electrically connected to one end of the second switch transistor, and serves as the positive electrode of the conversion capacitor of the entire switch capacitor voltage stabilization circuit, one end of the fourth switch transistor is electrically connected to one end of the third switch transistor, and serves as the negative electrode of the conversion capacitor of the entire switch capacitor voltage stabilization circuit, the first input end of the second logic controller serves as an enable end of the entire switch capacitor voltage stabilization circuit, and receives a control signal from a previous stage circuit, the other end of the fourth switch transistor is electrically connected to one end of the second output voltage divider upper resistor, and serves as a signal output end of the entire switch capacitor voltage stabilization circuit, the other end of the second output voltage divider upper resistor is electrically connected to one end of the second output voltage divider lower resistor, and both are electrically connected to the second input end of the second logic controller, and the output voltage divider signal is transmitted to the second logic controller, the other end of the second switch transistor is electrically connected to the other end of the third switch transistor and the other end of the second output voltage divider lower resistor, respectively, and serves as the wire grounding end of the entire switch capacitor voltage stabilization circuit.

[0022] A switching power supply system, comprising an output circuit as described above, and further comprising a rectifier device, an energy storage capacitor, a conversion capacitor and an output capacitor;

[0023] The input end of the rectifier device is electrically connected to the AC input line and serves as the input end of the entire switching power supply system. One end of the rectifier device is electrically connected to the signal input end of the output circuit, and the other end of the rectifier device is electrically connected to the system ground. The energy storage end of the output circuit is electrically connected to the positive electrode of the energy storage capacitor, and the signal output end of the output circuit is electrically connected to one end of the output capacitor. The two ends of the conversion capacitor are respectively electrically connected to the positive electrode of the conversion capacitor and the negative electrode of the conversion capacitor of the switching capacitor voltage stabilization circuit. The wire grounding end of the output circuit, the negative electrode of the energy storage capacitor and the other end of the output capacitor are all electrically connected to the system ground.

[0024] Preferably, the rectifying device is a rectifying bridge or a rectifying diode.

[0025] Preferably, in the operating state of the switching power supply system, the energy storage capacitor first completes the charging of the conversion capacitor, and then the conversion capacitor completes the charging of the output capacitor.

[0026] Preferably, in the operating state of the switching power supply system, the relationship among the voltage Vd of the energy storage capacitor, the voltage Vf of the conversion capacitor and the voltage Vo of the output capacitor is Vd ≥ Vf ≥ Vo.

[0027] Compared with the prior art, the advantages of the present invention are mainly reflected in the following aspects:

[0028] The output circuit proposed by the present invention is composed of a step-down circuit and a switch capacitor voltage stabilization circuit connected in sequence. The circuit structure is simple and intuitive, and the reliability and stability of the circuit as a whole are guaranteed to the maximum extent while ensuring the voltage output effect. At the same time, the output circuit of the present invention can also realize different forms of voltage output such as negative voltage output, half-voltage output and multi-channel output by changing the internal connection mode, and has various functions and a wide range of applications.

[0029] The output circuit of the present invention is applied to the switching power supply system, which can effectively optimize the entire switching power supply system and make the system structure more streamlined. The entire switching power supply system is composed of components such as rectifier devices, energy storage capacitors, conversion capacitors, and output capacitors, and there is no need to set up filter circuits and inductors. At the same time, all parts and components used in the present invention are common and readily available existing products and can all be installed and set up in an integrated manner, so that the manufacturing cost of the overall solution is greatly reduced.

[0030] In addition, the present invention also provides a reference for other related solutions in the same field, and can be expanded and extended based on this, and applied to the design of other negative voltage output circuits in the same field, and has broad application prospects.

[0031] The specific implementation modes of the present invention are further described below in combination with the accompanying drawings of the embodiments, so that the technical solutions of the present invention are easier to understand and grasp. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A schematic diagram of the hardware structure of the switching power supply system of the present invention;

[0033] Figure 2 It is a hardware structure diagram of a voltage-reducing circuit when the output circuit of the present invention is a negative voltage output circuit;

[0034] Figure 3 It is a hardware structure diagram of the switch capacitor voltage stabilizing circuit when the output circuit of the present invention is a negative voltage output circuit;

[0035] Figure 4 It is a schematic diagram of the hardware structure when the output circuit of the present invention is a half-voltage output circuit;

[0036] Figure 5 It is a schematic diagram of the hardware structure when the output circuit of the present invention is a multi-channel output circuit;

[0037] Wherein: 1. step-down circuit; 11. transistor; 12. input voltage divider upper resistor; 13. input voltage divider lower resistor; 14. first logic controller; 15. driver; 16. first output voltage divider upper resistor; 17. first output voltage divider lower resistor; 2. switch capacitor voltage stabilizing circuit; 21. second logic controller; 22. first switching transistor; 23. second switching transistor; 24. third switching transistor; 25. fourth switching transistor; 26. second output voltage divider upper resistor; 27. second output voltage divider lower resistor; 3. another switch capacitor voltage stabilizing circuit; 4. rectifier device; 5. energy storage capacitor; 6. conversion capacitor; 7. output capacitor. DETAILED DESCRIPTION

[0038] The present invention discloses an output circuit with high reliability and capable of realizing voltage output in various forms, and a switching power supply system using the circuit, as described in detail as follows.

[0039] An output circuit such as Figure 1 As shown, it includes a step-down circuit 1 for realizing voltage transformation regulation and a switch capacitor voltage stabilizing circuit 2 for realizing voltage stabilizing control; the step-down circuit 1 and the switch capacitor voltage stabilizing circuit 2 are connected in series in sequence.

[0040] The signal input terminal Vin1 of the step-down circuit 1 serves as the signal input terminal Vin of the entire output circuit; the control terminal CTRL1 of the step-down circuit 1 is electrically connected to the enable terminal EN2 of the switch capacitor voltage stabilizing circuit 2; the signal output terminal Vout1 of the step-down circuit 1 is electrically connected to the signal input terminal Vin2 of the switch capacitor voltage stabilizing circuit 2 and serves as the energy storage terminal VD of the entire output circuit; the signal output terminal Vout2 of the switch capacitor voltage stabilizing circuit 2 or the wire ground terminal GND2 serves as the signal input terminal Vout of the entire output circuit.

[0041] According to the different connection modes between the remaining parts of the step-down circuit 1 and the switch capacitor voltage stabilizing circuit 2, the entire output circuit has three different functional implementation forms, namely, a negative voltage output circuit, a half-voltage output circuit and a multi-channel output circuit.

[0042] First, when the entire output circuit is a negative voltage output circuit, the wire ground terminal GND1 of the step-down circuit 1 is electrically connected to the wire ground terminal GND2 of the switching capacitor voltage regulator circuit 2 and serves as the wire ground terminal GND of the entire output circuit, and the signal output terminal Vout2 of the switching capacitor voltage regulator circuit 2 serves as the signal output terminal Vout of the entire output circuit.

[0043] In this embodiment, the step-down circuit 1 is a chopper circuit, and its specific structure is as follows: Figure 2 shown.

[0044] The step-down circuit 1 includes a transistor 11 , an input voltage-dividing upper resistor 12 , an input voltage-dividing lower resistor 13 , a first logic controller 14 , a driver 15 , a first output voltage-dividing upper resistor 16 , and a first output voltage-dividing lower resistor 17 .

[0045] In the above hardware structure, the transistor 11 is a power transistor, which is used to provide a high-power output for the signal output terminal Vout1 of the entire buck circuit 1; the input voltage-dividing upper resistor 12 and the input voltage-dividing lower resistor 13 are mainly used to detect the input voltage; the first logic controller 14 is used to control the transistor 11 according to the input voltage detection results of the input voltage-dividing upper resistor 12 and the input voltage-dividing lower resistor 13, and generate an enable signal to control the subsequent circuit; the first output voltage-dividing upper resistor 16 and the first output voltage-dividing lower resistor 17 are mainly used to detect the output voltage of the signal output terminal Vout1 of the entire buck circuit 1.

[0046] The drain of the transistor 11 is electrically connected to one end of the input voltage-dividing upper resistor 12, serving as the signal input end of the entire step-down circuit 1. The other end of the input voltage-dividing upper resistor 12 is electrically connected to one end of the input voltage-dividing lower resistor 13, and both are electrically connected to the first input end of the first logic controller 14, transmitting the input voltage-dividing signal to the first logic controller 14. The first output end of the first logic controller 14 is electrically connected to the input end of the driver 15, and the output end of the driver 15 is electrically connected to the gate of the transistor 11. The second output end of the first logic controller 14 serves as the whole The control end CTRL1 of the step-down circuit 1, the source of the transistor 11 is electrically connected to the first output voltage-dividing upper resistor 16, serving as the signal output end Vout1 of the entire step-down circuit 1, the other end of the first output voltage-dividing upper resistor 16 is electrically connected to one end of the first output voltage-dividing lower resistor 17 and both are electrically connected to the second input end of the first logic controller 14, transmitting the output voltage-dividing signal to the first logic controller 14; the other end of the input voltage-dividing lower resistor 13 is electrically connected to the other end of the first output voltage-dividing lower resistor 17, serving as the wire grounding end GND1 of the entire step-down circuit 1.

[0047] In this embodiment, the switch capacitor voltage stabilizing circuit 2 is a charge pump circuit, and its specific structure is as follows: Figure 3 shown.

[0048] The switch capacitor voltage stabilizing circuit 2 includes a second logic controller 21 , a first switch transistor 22 , a second switch transistor 23 , a third switch transistor 24 , a fourth switch transistor 25 , a second output voltage dividing upper resistor 26 , and a second output voltage dividing lower resistor 27 .

[0049] In the above hardware structure, the second output voltage-dividing upper resistor 26 and the second output voltage-dividing lower resistor 27 are mainly used to detect the output voltage of the signal output terminal Vout2 of the entire switching capacitor voltage-stabilizing circuit 2; the second logic controller 21 is used to control the opening and closing of the first switching transistor 22, the second switching transistor 23, the third switching transistor 24 and the fourth switching transistor 25 according to the voltage detection results of the second output voltage-dividing upper resistor 26 and the second output voltage-dividing lower resistor 27 and the control signal of the enable terminal EN2 of the entire switching capacitor voltage-stabilizing circuit 2.

[0050] One end of the first switch transistor 22 serves as the signal input terminal Vin2 of the entire switch capacitor voltage stabilizing circuit 2, the other end of the first switch transistor 22 is electrically connected to one end of the second switch transistor 23, and serves as the positive electrode Fly+ of the conversion capacitor of the entire switch capacitor voltage stabilizing circuit 2, one end of the fourth switch transistor 25 is electrically connected to one end of the third switch transistor 24, and serves as the negative electrode Fly- of the conversion capacitor of the entire switch capacitor voltage stabilizing circuit 2, the first input end of the second logic controller 21 serves as the enable terminal EN2 of the entire switch capacitor voltage stabilizing circuit 2, and receives the control signal from the previous stage circuit, and the fourth switch transistor The other end of the tube 25 is electrically connected to one end of the second output voltage-dividing upper resistor 26, serving as the signal output terminal Vout2 of the entire switched capacitor voltage-stabilizing circuit 2; the other end of the second output voltage-dividing upper resistor 26 is electrically connected to one end of the second output voltage-dividing lower resistor 27, and both are electrically connected to the second input terminal of the second logic controller 21, transmitting the output voltage-dividing signal to the second logic controller 21; the other end of the second switching transistor 23 is electrically connected to the other end of the third switching transistor 24 and the other end of the second output voltage-dividing lower resistor 27, serving as the wire grounding terminal GND2 of the entire switched capacitor voltage-stabilizing circuit 2.

[0051] Secondly, when the entire output circuit is a half-voltage output circuit, the hardware connection relationship at this time is as follows Figure 4 shown.

[0052] At this time, the wire ground terminal GND1 of the step-down circuit 1 is electrically connected to the signal output terminal Vout2 of the switching capacitor voltage regulator circuit 2 and serves as the wire ground terminal GND of the entire output circuit, and the wire ground terminal GND2 of the switching capacitor voltage regulator circuit 2 serves as the signal output terminal Vout of the entire output circuit.

[0053] In addition, when the entire output circuit is a multi-channel output circuit, the hardware connection relationship at this time is as follows Figure 5 shown.

[0054] The wire grounding terminal GND1 of the step-down circuit 1 is electrically connected to the signal output terminal Vout2 of the switching capacitor voltage regulator circuit 2 and serves as the wire grounding terminal GND of the entire output circuit. The wire grounding terminal GND2 of the switching capacitor voltage regulator circuit 2 serves as the signal output terminal VoutA of the entire output circuit.

[0055] At this time, the output circuit also includes another switched capacitor voltage regulator circuit 3; the enable end EN3 of the other switched capacitor voltage regulator circuit 3 is electrically connected to the control end CTRL1 of the buck circuit 1, the signal input end Vin3 of the other switched capacitor voltage regulator circuit 3 is electrically connected to the signal output end Vout1 of the buck circuit 1, and they together serve as the energy storage end VD of the entire output circuit, the wire grounding end GND3 of the other switched capacitor voltage regulator circuit 3 is electrically connected to the wire grounding end GND1 of the buck circuit 1, and they together serve as the wire grounding end GND of the entire output circuit, and the signal output end Vout3 of the other switched capacitor voltage regulator circuit 3 serves as another signal output end VoutB of the entire output circuit.

[0056] It should be noted that, whether in the switched capacitor voltage regulator circuit 2 or the other switched capacitor voltage regulator circuit 3, the function and operation standard of the enable end are the same, that is, when the voltage signal received by the enable end is low, the circuit to which the enable end belongs does not work and does not generate a voltage signal output; when the voltage signal received by the enable end is high, the circuit to which the enable end belongs works, generates a voltage signal output and maintains the voltage within a preset voltage range.

[0057] A switching power supply system, such as Figure 1 As shown, it includes an output circuit as described above, and further includes a rectifier device 4, a storage capacitor 5, a conversion capacitor 6 and an output capacitor 7;

[0058] The input end of the rectifier device 4 is electrically connected to the AC input line and serves as the input end of the entire switching power supply system. One end of the rectifier device 4 is electrically connected to the signal input end Vin of the output circuit, and the other end of the rectifier device 4 is electrically connected to the system ground. The energy storage end VD of the output circuit is electrically connected to the positive electrode of the energy storage capacitor 5, and the signal output end Vout of the output circuit is electrically connected to one end of the output capacitor 7. The two ends of the conversion capacitor 6 are respectively electrically connected to the positive electrode Fly+ and the negative electrode Fly- of the conversion capacitor of the switching capacitor voltage stabilizing circuit 2. The wire grounding end GND of the output circuit, the negative electrode of the energy storage capacitor 5 and the other end of the output capacitor 7 are all electrically connected to the system ground.

[0059] In the solution of the present invention, the rectifier device 4 is preferably a rectifier bridge or a rectifier diode.

[0060] It should also be noted that, in the operating state of the switching power supply system, the energy storage capacitor 5 first completes the charging of the conversion capacitor 6 , and then the conversion capacitor 6 completes the charging of the output capacitor 7 .

[0061] Furthermore, in the operating state of the switching power supply system, the relationship among the voltage Vd of the energy storage capacitor 5, the voltage Vf of the conversion capacitor 6 and the voltage Vo of the output capacitor is: Vd ≥ Vf ≥ Vo.

[0062] In summary, the output circuit proposed by the present invention is composed of a step-down circuit and a switch capacitor voltage stabilization circuit connected in sequence. The circuit structure is simple and intuitive, and the reliability and stability of the circuit as a whole are guaranteed to the maximum extent while ensuring the voltage output effect. At the same time, the output circuit of the present invention can also realize different forms of voltage output such as negative voltage output, half-voltage output and multi-channel output by changing the internal connection mode, with diverse functions and a wide range of applications.

[0063] The output circuit of the present invention is applied to the switching power supply system, which can effectively optimize the entire switching power supply system and make the system structure more streamlined. The entire switching power supply system is composed of a rectifier device, an output circuit, an energy storage capacitor, a conversion capacitor and an output capacitor, and there is no need to set a filter circuit and an inductor. At the same time, all parts and components used in the present invention are common and readily available existing products and can all be installed and set up in an integrated manner, so that the manufacturing cost of the overall solution is greatly reduced.

[0064] In addition, the present invention also provides a reference for other related solutions in the same field, and can be expanded and extended based on this, and applied to the design solutions of other output circuits in the same field, and has broad application prospects.

[0065] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit and essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-limiting from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any reference numerals in the claims should not be regarded as limiting the claims involved.

[0066] Finally, it should be understood that although this specification is described according to implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. An output circuit, characterized in that: It comprises a step-down circuit (1) for realizing voltage transformation regulation and a switched capacitor voltage stabilizing circuit (2) for realizing voltage stabilizing control, wherein the step-down circuit (1) and the switched capacitor voltage stabilizing circuit (2) are connected in series in sequence, the signal input end of the step-down circuit (1) serves as the signal input end of the entire output circuit, the control end of the step-down circuit (1) is electrically connected to the enable end of the switched capacitor voltage stabilizing circuit (2), the signal output end of the step-down circuit (1) is electrically connected to the signal input end of the switched capacitor voltage stabilizing circuit (2) and serves as the energy storage end of the entire output circuit, and the signal output end or the wire grounding end of the switched capacitor voltage stabilizing circuit (2) serves as the signal output end of the entire output circuit; The step-down circuit (1) is a chopper circuit; the step-down circuit (1) comprises a transistor (11), an input voltage-dividing upper resistor (12), an input voltage-dividing lower resistor (13), a first logic controller (14), a driver (15), a first output voltage-dividing upper resistor (16), and a first output voltage-dividing lower resistor (17); The drain of the transistor (11) is electrically connected to one end of the input voltage-dividing upper resistor (12) and serves as the signal input end of the entire step-down circuit (1); the other end of the input voltage-dividing upper resistor (12) is electrically connected to one end of the input voltage-dividing lower resistor (13), and both are electrically connected to the first input end of the first logic controller (14), transmitting the input voltage-dividing signal to the first logic controller (14); the first output end of the first logic controller (14) is electrically connected to the input end of the driver (15); the output end of the driver (15) is electrically connected to the gate of the transistor (11); and the output end of the first logic controller (14) is electrically connected to the gate of the transistor (11). The second output end serves as the control end of the entire step-down circuit (1); the source of the transistor (11) is electrically connected to the first output voltage-dividing upper resistor (16) and serves as the signal output end of the entire step-down circuit (1); the other end of the first output voltage-dividing upper resistor (16) is electrically connected to one end of the first output voltage-dividing lower resistor (17) and both are electrically connected to the second input end of the first logic controller (14) to transmit the output voltage-dividing signal to the first logic controller (14); the other end of the input voltage-dividing lower resistor (13) is electrically connected to the other end of the first output voltage-dividing lower resistor (17) and serves as the wire grounding end of the entire step-down circuit (1); The switched capacitor voltage stabilization circuit (2) is a charge pump circuit; the switched capacitor voltage stabilization circuit (2) comprises a second logic controller (21), a first switch transistor (22), a second switch transistor (23), a third switch transistor (24), a fourth switch transistor (25), a second output voltage divider upper resistor (26) and a second output voltage divider lower resistor (27), and the four output terminals of the second logic controller (21) are connected one-to-one to the control terminals of the switch transistors; One end of the first switch transistor (22) serves as a signal input end of the entire switch capacitor voltage stabilization circuit (2); the other end of the first switch transistor (22) is electrically connected to one end of the second switch transistor (23) and serves as the positive electrode of the conversion capacitor of the entire switch capacitor voltage stabilization circuit (2); one end of the fourth switch transistor (25) is electrically connected to one end of the third switch transistor (24) and serves as the negative electrode of the conversion capacitor of the entire switch capacitor voltage stabilization circuit (2); the first input end of the second logic controller (21) serves as an enable end of the entire switch capacitor voltage stabilization circuit (2) and receives a control signal from a previous stage circuit; the fourth switch transistor (25) ) is electrically connected to one end of the second output voltage-dividing upper resistor (26) to serve as the signal output end of the entire switched capacitor voltage-stabilizing circuit (2); the other end of the second output voltage-dividing upper resistor (26) is electrically connected to one end of the second output voltage-dividing lower resistor (27) and both are electrically connected to the second input end of the second logic controller (21) to transmit the output voltage-dividing signal to the second logic controller (21); the other end of the second switching transistor (23) is electrically connected to the other end of the third switching transistor (24) and the other end of the second output voltage-dividing lower resistor (27) to serve as the wire grounding end of the entire switched capacitor voltage-stabilizing circuit (2).

2. An output circuit according to claim 1, characterized in that: The entire output circuit is a negative voltage output circuit; the wire grounding end of the step-down circuit (1) is electrically connected to the wire grounding end of the switch capacitor voltage stabilizing circuit (2) and serves as the wire grounding end of the entire output circuit; the signal output end of the switch capacitor voltage stabilizing circuit (2) serves as the signal output end of the entire output circuit.

3. An output circuit according to claim 1, characterized in that: The entire output circuit is a half-voltage output circuit; the wire grounding end of the step-down circuit (1) is electrically connected to the signal output end of the switch capacitor voltage stabilizing circuit (2) and serves as the wire grounding end of the entire output circuit, and the wire grounding end of the switch capacitor voltage stabilizing circuit (2) serves as the signal output end of the entire output circuit.

4. The output circuit according to claim 1, characterized in that: The entire output circuit is a multi-channel output circuit; the wire grounding end of the step-down circuit (1) is electrically connected to the signal output end of the switch capacitor voltage regulator circuit (2) and serves as the wire grounding end of the entire output circuit, and the wire grounding end of the switch capacitor voltage regulator circuit (2) serves as the signal output end of the entire output circuit; the entire output circuit also includes another switch capacitor voltage regulator circuit (3), the enable end of the other switch capacitor voltage regulator circuit (3) is electrically connected to the control end of the step-down circuit (1), the signal input end of the other switch capacitor voltage regulator circuit (3) is electrically connected to the signal output of the step-down circuit (1), and together they serve as the energy storage end of the entire output circuit, the wire grounding end of the other switch capacitor voltage regulator circuit (3) is electrically connected to the wire grounding end of the step-down circuit (1), and together they serve as the wire grounding end of the entire output circuit, and the signal output end of the other switch capacitor voltage regulator circuit (3) serves as another signal output end of the entire output circuit.

5. A switching power supply system, comprising an output circuit as claimed in any one of claims 1 to 4, characterized in that: The invention also includes a rectifier (4), an energy storage capacitor (5), a conversion capacitor (6) and an output capacitor (7); the input end of the rectifier (4) is electrically connected to the AC input line and serves as the input end of the entire switching power supply system; one end of the rectifier (4) is electrically connected to the signal input end of the output circuit; the other end of the rectifier (4) is electrically connected to the system ground; the energy storage end of the output circuit is electrically connected to the positive electrode of the energy storage capacitor (5); the signal output end of the output circuit is electrically connected to one end of the output capacitor (7); the two ends of the conversion capacitor (6) are respectively electrically connected to the positive electrode and the negative electrode of the conversion capacitor of the switching capacitor stabilizing circuit (2); the wire grounding end of the output circuit, the negative electrode of the energy storage capacitor (5) and the other end of the output capacitor (7) are all electrically connected to the system ground.

6. The switching power supply system according to claim 5, characterized in that: The rectifier device (4) is a rectifier bridge or a rectifier diode.

7. The switching power supply system according to claim 5, characterized in that: When the switching power supply system is in operation, the energy storage capacitor (5) first completes charging of the conversion capacitor (6), and then the conversion capacitor (6) completes charging of the output capacitor (7).

8. The switching power supply system according to claim 5, characterized in that: When the switching power supply system is in operation, the relationship among the voltage Vd of the energy storage capacitor (5), the voltage Vf of the conversion capacitor (6) and the voltage Vo of the output capacitor is: Vd ≥ Vf ≥ Vo.

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