Switching power supply and charger

Abstract

The utility model provides a switching power supply and a charger comprising the switching power supply, the switching power supply comprises an input circuit, a surge suppression circuit, a rectification filtering energy storage circuit, a DC-DC conversion circuit and an output circuit, the surge suppression circuit comprises an NTC thermistor and a temperature switch which are connected in parallel, the operating temperature of the temperature switch is larger than or equal to the surface temperature of the NTC thermistor during working, and the temperature switch is in a normally-open state. According to the invention, the temperature switch is automatically closed to short-circuit the NTC thermistor when the temperature of the NTC thermistor or a product to which the NTC thermistor is applied rises, and is automatically switched off when the temperature of the NTC thermistor decreases to enable the NTC thermistor to recover to a working state, so that the surge current in the switching power supply circuit is suppressed; the power loss caused by extra temperature rise generated by the NTC thermistor is effectively reduced; the temperature switch is small in size, the area occupied by the surge suppression circuit is reduced, and miniaturization of the switching power supply and the charger is facilitated.

Description

Technical Field

[0001] The utility model relates to the technical field of energy-saving protection of switching power supplies, in particular to a switching power supply and a charger. Background Art

[0002] As switching power supplies are currently developing towards high power density, small size, and high efficiency, the requirements for reliability are also becoming increasingly higher. When the switching power supply is turned on, the large electrolytic capacitor storing energy on the primary side is in a state similar to a short circuit, with a resistance value close to zero. As a result, the main circuit will generate a startup surge current of tens or hundreds of amperes at the moment of startup.

[0003] In the prior art, common methods for suppressing inrush current include: first, using a power resistor connected in series with the input circuit of the power supply, which can effectively limit the inrush current at startup. However, to reduce the inrush current, a larger resistor value is required, and the resistance value does not change with temperature. While limiting the inrush current, it also consumes a certain amount of power, reducing the conversion efficiency of the power supply. During the entire power supply operation process, the resistor will continue to consume power, even in steady-state operation. In some cases, an additional heat dissipation system needs to be designed. The second method is to use an NTC thermistor, especially an NTC thermistor with a negative temperature coefficient. NTC thermistors are used in the initial stage of power supply startup. The NTC thermistor is at room temperature and has a high resistance value, which can effectively limit the inrush current. As the power supply operates for an increasing amount of time, the temperature of the NTC thermistor rises due to its own heat, and the resistance gradually decreases, and the impact on the circuit also decreases. However, the temperature of the NTC thermistor element itself is very high, which will cause the temperature of the product to which it is applied to rise, resulting in heating. The third method is to add a relay to the NTC thermistor based on the second method. The relay is used to bypass the NTC thermistor from the circuit after the power supply stabilizes, thereby reducing its power consumption under normal operating conditions and extending its service life. However, although this method can solve the problems of high temperature and large losses, the circuit size and number of components after the combination are large, and the cost is high. It is generally only suitable for applications where cost and product size are not a high requirement. Utility Model Content

[0004] The utility model provides a switching power supply and a charger, which can solve the technical problems of high temperature, large power loss and large occupied volume in the operation process of the surge suppression circuit in the existing switching power supply.

[0005] In a first aspect, an embodiment of the present application provides a switching power supply, comprising:

[0006] An input circuit, used for obtaining an externally inputted AC input voltage;

[0007] a surge suppression circuit, connected to the input circuit, for suppressing surge current in the circuit;

[0008] a rectifier filtering energy storage circuit, connected to the surge suppression circuit, for converting the AC input voltage into a DC voltage and performing filtering;

[0009] A DC-DC conversion circuit is connected to the rectifier and filter energy storage circuit, and is used to convert the rectified and filtered DC voltage into a target DC output voltage;

[0010] an output circuit, connected to the DC-DC conversion circuit, and configured to output the target DC output voltage;

[0011] The input circuit is connected to a fuse F1; the surge suppression circuit includes an NTC thermistor and a temperature switch connected in parallel; and the operating temperature of the temperature switch is greater than or equal to the surface temperature of the NTC thermistor when working, and the temperature switch is in a normally open state.

[0012] In some embodiments, the switching power supply further includes an anti-electromagnetic interference circuit connected between the surge suppression circuit and the rectifier circuit, for suppressing or reducing electromagnetic interference in the switching power supply circuit.

[0013] In some embodiments, the anti-electromagnetic interference circuit includes an inductor LF1, a resistor RX1, a resistor RX2, a resistor RX3, a resistor RX4 and a capacitor CX1;

[0014] The first input end of the inductor LF1 is connected to the second end of the fuse F1, and the second input end of the inductor LF1 is connected to one end of the NTC thermistor; the resistor RX1 and the resistor RX2 are connected in series, the first end of the resistor RX1 is connected to the first output end of the inductor LF1, and the second end of the resistor RX2 is connected to the second output end of the inductor LF1; the resistor RX3 and the resistor RX4 are connected in series, the first end of the resistor RX3 is connected to the first output end of the inductor LF1, and the second end of the resistor RX4 is connected to the second output end of the inductor LF1; the first end of the capacitor CX1 is connected to the first output end of the inductor LF1, and the second end of the capacitor CX1 is connected to the second output end of the inductor LF1.

[0015] In some embodiments, the rectifier-filtering tank circuit includes a rectifier BR1, a storage capacitor EC1, an inductor L4, a storage capacitor EC2, and a capacitor C18;

[0016] The first end of the rectifier BR1 is connected to the first input end of the rectifier and filter energy storage circuit, and the second end of the rectifier BR1 is connected to the second input end of the rectifier and filter energy storage circuit; the first end of the energy storage capacitor EC1 is connected to the first output end of the rectifier BR1, and the second end of the energy storage capacitor EC1 is connected to the second output end of the rectifier BR1; the first end of the inductor L4 is connected to the first end of the energy storage capacitor EC1; the first end of the energy storage capacitor EC2 is connected to the second end of the inductor L4, and the second end of the energy storage capacitor EC2 is connected to the first preset voltage end; the first end of the capacitor C18 is connected to the first end of the energy storage capacitor EC2, and the second end of the capacitor C18 is connected to the first preset voltage end.

[0017] In some embodiments, the DC-DC conversion circuit includes a transformer, an EMI absorption capacitor C2, a synchronous rectification module, and parallel energy storage capacitors EC5, EC6 and C13; the first end of the transformer input winding is connected to the input end of the DC-DC conversion circuit; the EMI absorption capacitor C2 is connected in parallel to the transformer input winding; the input end of the synchronous rectification module is connected to the second end of the transformer output winding, and the output end of the synchronous rectification module is connected to the second preset voltage end; the first end of the energy storage capacitor EC5 is connected to the first end of the transformer output winding and the output end of the DC-DC conversion circuit, and the second end of the energy storage capacitor EC5 is connected to the second preset voltage end.

[0018] In some embodiments, the synchronous rectification module includes a switch tube M1, a control chip U2, a resistor R19, a resistor R17, a capacitor C12, a resistor R18, a resistor R20, a capacitor C17, and a capacitor C18;

[0019] The first end of the switch tube M1 is connected to the input end of the synchronous rectifier module, the second end of the switch tube M1 is connected to the output end of the synchronous rectifier module, and the control end of the switch tube M1 is connected to the GATE pin of the control chip U2; the first end of the resistor R19 is connected to the first end of the switch tube M1, and the second end of the resistor R19 is connected to the DESN pin of the control chip U2; the resistor R17 and the capacitor C12 are connected in series, the first end of the resistor R17 is connected to the first end of the switch tube M1, and the second end of the capacitor C12 is connected to the second end of the switch tube M1; the first end of the resistor R18 is connected to the REG pin of the control chip U2, the first end of the resistor R20 is connected to the TZ pin of the control chip U2, the first end of the capacitor C17 is connected to the VDD pin of the control chip U2, the first end of the capacitor C18 is connected to the VIN pin of the control chip U2, and the second ends of the resistor R18, the resistor R20, the capacitor C17, and the capacitor C18 are all connected to the second preset voltage end.

[0020] In some embodiments, the DC-DC conversion circuit further includes a power control module; the power control module includes a magnetic bead FB1, a control chip U1, a capacitor C11, a resistor R14, a resistor R15, a resistor R7, a capacitor C3, a resistor R8, a transformer auxiliary winding T1B, an energy storage capacitor EC3, a capacitor C5, a resistor R11, a diode D5, a resistor R9, a resistor R10, a capacitor C8, an optocoupler PC1B, a Zener diode ZD1, a resistor R12, and a capacitor C9;

[0021] The first end of the magnetic bead FB1 is connected to the second end of the transformer input winding, and the second end of the magnetic bead FB1 is connected to at least one SW pin of the control chip U1; the first end of the capacitor C11 is connected to the second end of the magnetic bead FB1, and the second end of the capacitor C11 is connected to at least one CS pin of the control chip U1; the resistor R14 and the resistor R15 are connected in parallel, the first end of the resistor R14 is connected to the second end of the capacitor C11, and the second end of the resistor R14 is connected to the GND pin of the control chip U1 and the first preset voltage terminal;

[0022] The first end of the resistor R7 is connected to the VDD pin of the control chip U1; the first end of the capacitor C3 is connected to the second end of the resistor R7; the first end of the resistor R8 is connected to the second end of the capacitor C3; the first end of the transformer auxiliary winding T1B is connected to the second end of the resistor R8, and the second end of the transformer auxiliary winding T1B is connected to the first preset voltage terminal;

[0023] The energy storage capacitor EC3 and the capacitor C5 are connected in parallel, the first end of the energy storage capacitor EC3 is connected to the first end of the resistor R7, and the second end of the energy storage capacitor EC3 is connected to the first preset voltage end; the first end of the resistor R11 is connected to the second end of the capacitor C5, and the resistor R11 is connected to the FEST pin of the control chip U1; the first end of the diode D5 is connected to the second end of the resistor R7, and the second end of the diode D5 is connected to the second end of the resistor R8;

[0024] The first end of the resistor R9 is connected to the second end of the diode D5; the first end of the resistor R10 is connected to the second end of the resistor R9, and the second end of the resistor R10 is connected to the first preset voltage end; the first end of the capacitor C8 is connected to the second end of the resistor R9 and the DMG pin of the control chip U1, and the second end of the capacitor C8 is connected to the first preset voltage end; the optocoupler PC1B and the Zener diode ZD1 are connected in parallel, and the second end of the optocoupler PC1B is connected to the first preset voltage end; the first end of the resistor R12 is connected to the first end of the optocoupler PC1B, and the second end of the resistor R12 is connected to the FB pin of the control chip U1; the first end of the capacitor C9 is connected to the second end of the resistor R12, and the second end of the capacitor C9 is connected to the first preset voltage end.

[0025] In some embodiments, the DC-DC conversion circuit further includes an RCD absorption module; the RCD absorption module includes a diode D3, a resistor R2, a resistor R3, a capacitor C1, a resistor R4, and a resistor R5;

[0026] The resistor R2, the resistor R3 and the capacitor C1 are connected in parallel, the first end of the resistor R2 is connected to the first end of the transformer input winding; the first end of the resistor R4 is connected to the second end of the resistor R2; the first end of the diode D3 is connected to the second end of the resistor R4, and the second end of the diode D3 is connected to the second end of the magnetic bead FB1; the first end of the resistor R5 is connected to the second end of the capacitor C1, and the second end of the resistor R5 is connected to the second end of the resistor R4.

[0027] In some embodiments, the switching power supply further includes a voltage regulation and feedback control circuit; the voltage regulation and feedback control circuit includes a resistor R24, a resistor R27, a switch tube M2, a resistor R26, a resistor R25, a resistor R21, an optocoupler PC1A, a voltage regulator chip U3, a capacitor C16, a resistor R22, a resistor R23, and a capacitor C17;

[0028] The first end of the resistor R24 ​​is connected to the output circuit; the first end of the resistor R27 is connected to the second end of the resistor R24; the first end of the switch tube M2 is connected to the second end of the resistor R27, the second end of the switch tube M2 is connected to the second preset voltage end, and the control end of the switch tube M2 is used to obtain the external input adjustment signal; the resistor R26 and the resistor R25 are connected in parallel, the first end of the resistor R26 is connected to the second end of the resistor R24, and the second end of the resistor R26 is connected to the second preset voltage end; the first end of the resistor R21 is connected to the first end of the resistor R24; the first end of the optocoupler PC1A is connected to the The first end of the voltage stabilizing chip U3 is connected to the second end of the optocoupler PC1A, the second end of the voltage stabilizing chip U3 is connected to the second preset voltage end, and the third end of the voltage stabilizing chip U3 is connected to the first end of the resistor R26; the first end of the capacitor C16 is connected to the first end of the resistor R24; the first end of the resistor R22 is connected to the second end of the capacitor C16, and the second end of the resistor R22 is connected to the first end of the voltage stabilizing chip U3; the resistor R23 and the capacitor C17 are connected in series, the first end of the resistor R23 is connected to the second end of the resistor R22, and the second end of the capacitor C17 is connected to the second end of the resistor R24.

[0029] In a second aspect, an embodiment of the present application further provides a charger, comprising an adapter for converting alternating current into direct current, and a data cable connected to the adapter;

[0030] Wherein, the adapter includes the switching power supply as described in any embodiment of the first aspect.

[0031] The present invention provides a switching power supply and a charger including the switching power supply. The switching power supply includes an input circuit, a surge suppression circuit, a rectifier filter energy storage circuit, a DC-DC converter circuit, and an output circuit. The surge suppression circuit includes an NTC thermistor and a temperature switch connected in parallel. The operating temperature of the temperature switch is greater than or equal to the surface temperature of the NTC thermistor during operation, and the temperature switch is in a normally open state. The present invention uses a temperature switch that automatically closes and short-circuits the NTC thermistor when the temperature of the NTC thermistor or the product to which it is applied rises, and automatically opens and returns the NTC thermistor to its operating state when the temperature of the NTC thermistor drops. This effectively reduces power loss caused by the additional temperature rise of the NTC thermistor while suppressing inrush current in the switching power supply circuit. Compared with existing switching circuits such as relays, the temperature switch has a smaller size, reduces the area occupied by the surge suppression circuit, and is conducive to the miniaturization of the switching power supply and charger. The present invention has the advantages of simple structure, low power consumption, and high reliability, and improves product power density, cost-effectiveness, and universal applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0033] Figure 1 A schematic diagram of the structure of a switching power supply provided in one embodiment of the present application;

[0034] Figure 2 A schematic diagram of the structure of a switching power supply provided in another embodiment of the present application;

[0035] Figure 3 A circuit diagram of a switching power supply provided in one embodiment of the present application.

[0036] The above drawings illustrate specific embodiments of the present application, which will be described in more detail below. These drawings and the textual description are not intended to limit the scope of the present application in any way, but rather to illustrate the concepts of the present application to those skilled in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0037] The present invention is further described in detail below by means of specific embodiments in conjunction with the accompanying drawings. Similar elements in different embodiments are numbered with associated similar elements. In the following embodiments, many detailed descriptions are provided to enable the present application to be better understood. However, those skilled in the art will readily appreciate that some of the features may be omitted under different circumstances, or may be replaced by other elements, materials, or methods. In some cases, some operations related to the present application are not shown or described in the specification. This is to avoid the core portion of the present application being overwhelmed by excessive descriptions. For those skilled in the art, it is not necessary to describe these related operations in detail. They can fully understand the related operations based on the description in the specification and the general technical knowledge in the art.

[0038] In addition, the features, operations, or characteristics described in the specification may be combined in any appropriate manner to form various embodiments. Furthermore, the steps or actions in the method description may be reordered or adjusted in a manner readily apparent to those skilled in the art. Therefore, the various sequences in the specification and drawings are provided solely for the purpose of clearly describing a particular embodiment and are not intended to be mandatory, unless otherwise specified.

[0039] The terms "first", "second", etc. in the specification and claims of this application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally a class, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated before and after are in an "or" relationship. The "connection" and "connection" mentioned in this application, unless otherwise specified, include direct and indirect connections (connections).

[0040] The following specific embodiments describe in detail the technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0041] Figure 1 This is a schematic diagram of the structure of a switching power supply provided by an embodiment of the present application. Figure 1 As shown, the switching power supply provided in this embodiment includes an input circuit 110 , a surge suppression circuit 120 , a rectifier filter tank circuit 130 , a DC-DC conversion circuit 140 and an output circuit 150 .

[0042] In this embodiment, the input circuit 110 is used to obtain an external AC input voltage. The input circuit 110 is the connection part between the switching power supply and the external power grid, and is generally directly connected to the mains to receive AC power provided by the grid.

[0043] In some embodiments, a fuse F1 is connected to the input circuit 110 of the switching power supply, which is mainly used to protect the input circuit and the output circuit. When the current in the circuit exceeds the rated value of the fuse, the fuse will melt, thereby cutting off the circuit, preventing the current from continuing to pass through and damaging other components in the circuit, and preventing circuit damage caused by abnormal conditions such as overcurrent or short circuit. In a switching power supply, a fuse is usually connected in series in the input circuit to protect the power supply from inrush current and high-voltage surges (such as lightning strikes). Specifically, the fuse is generally installed on the L line of the input line because the L line is the live wire and carries the main current in the circuit. The N line (neutral line) usually maintains zero potential. If the fuse is connected to the N line, it will not only fail to effectively protect the circuit, but may also pose a safety hazard.

[0044] In this embodiment, the surge suppression circuit 120 is connected to the input circuit 110 to suppress inrush current in the circuit, particularly the inrush current generated during startup of the switching power supply, thereby protecting the components within the power supply from damage. In some embodiments, the surge suppression circuit 120 can be implemented using a variety of methods, such as a series negative temperature coefficient (NTC) thermistor, a power resistor, or a series constant resistor with a thyristor.

[0045] In this embodiment, the surge suppression circuit 120 includes an NTC thermistor and a switching circuit. The switching circuit is a temperature switch connected in parallel with the NTC thermistor. The operating temperature of the temperature switch is greater than or equal to the surface temperature of the NTC thermistor during operation, and the temperature switch is in a normally open state.

[0046] It is understandable that, according to the characteristics of the NTC thermistor, when the power supply is started, the surface temperature of the NTC thermistor is close to room temperature. At this time, its resistance is relatively high, which can effectively limit the current. As the working time of the power supply increases, the NTC thermistor dissipates heat and heats up, and its resistance gradually decreases, and its current limiting effect weakens. In this embodiment, a temperature switch is connected in parallel at both ends of the NTC thermistor. Under normal circumstances, the temperature switch is in the off state. When the power is turned on, the NTC thermistor plays a surge suppression role and generates heat. The heat is transferred to the temperature switch. The operating temperature of the temperature switch corresponds to the surface temperature of the NTC thermistor during operation (when the NTC thermistor is working, a certain current passes through the NTC thermistor and generates heat, so the surface temperature of the NTC thermistor during operation is greater than room temperature). After the NTC thermistor heats up, it generates additional heat, reaching the operating temperature of the temperature switch. The temperature switch closes, short-circuiting the NTC thermistor, and almost no current flows through the NTC thermistor. Current flows through the temperature switch and forms a path with the load circuit. The temperature switch's resistance under steady-state current is much smaller than that of the NTC thermistor. Therefore, even without current flowing through the NTC thermistor, power consumption can be kept low, significantly reducing the temperature of the NTC thermistor. Since almost no current flows through the NTC thermistor, the NTC thermistor begins to cool. When the NTC thermistor cools to room temperature, the operating temperature of the temperature switch corresponds to the surface temperature of the NTC thermistor during operation, and the temperature switch returns to its normally open state. At this point, the temperature switch is in an open state, and the NTC thermistor is reconnected in series with the load circuit. The next time a surge current flows through, the above process repeats. In other words, in this embodiment, the surge suppression circuit 120 employs an NTC thermistor and a temperature switch, which has the advantages of simple structure, high reliability, and wide application.

[0047] In some embodiments, NTC thermistors are chip-type, offering advantages such as compact structure, strong resistance to environmental influences, rapid response, and ease of use. They are widely used in temperature measurement, temperature control, and temperature protection. Chip NTC thermistors are small and leadless, making them suitable for high-density surface mounting. They are resistant to certain environmental interferences, maintain stable performance, and respond quickly to temperature changes, quickly reflecting temperature fluctuations. They are also easy to install and use, eliminating the need for complex commissioning and maintenance. When combined with a temperature switch, their surface can conform to the switch, allowing the switch to more accurately detect temperature changes.

[0048] It should be noted that for switching power supplies of different power ranges, different specifications of SMD NTC components and different temperature grade temperature switches can be selected for combination according to the voltage and / or current in the circuit.

[0049] In this embodiment, the rectifier-filter tank circuit 130 is connected to the surge suppression circuit 120 and is used to convert the AC input voltage into a DC voltage and perform filtering. Generally, the rectifier-filter tank circuit 130 includes components such as a rectifier bridge, a filter capacitor, and a storage inductor. The rectifier bridge converts AC power into DC power, the filter capacitor smoothes the pulsating components in the DC voltage, and the storage inductor provides energy buffering when the power supply output current changes.

[0050] The DC-DC converter circuit 140 is connected to the rectifier filter tank circuit 130 and is used to convert the rectifier and filtered DC voltage into a target DC output voltage. The DC-DC converter circuit 140 is the core part of the switching power supply, which converts the DC voltage provided by the rectifier filter tank circuit 130 into the voltage or current required by the user end (load). Generally, the DC-DC converter circuit 140 adjusts the output voltage or current by controlling the switching time ratio of high-frequency switching elements (such as MOSFETs). Under the action of the control circuit, the high-frequency switching elements are quickly switched on and off, converting the DC voltage into a high-frequency AC voltage, which is then converted into a stable DC voltage or current through the output rectifier filter circuit.

[0051] Output circuit 150 is connected to DC-DC converter circuit 140 and is used to output the target DC output voltage. Output circuit 150 connects the switching power supply to the user-end device (load), and is used to deliver the stable DC voltage or current provided by DC-DC converter circuit 140 to the user-end device (load).

[0052] The switching power supply provided in the embodiment of the present application automatically closes the NTC thermistor to short-circuit the NTC thermistor when the temperature of the NTC thermistor or the product to which it is applied rises, and automatically opens the NTC thermistor to restore the NTC thermistor to a working state when the temperature of the NTC thermistor drops. This effectively reduces the power loss caused by the additional temperature rise of the NTC thermistor while suppressing the inrush current in the switching power supply circuit. In addition, compared with existing switching circuits such as relays, the temperature switch has a smaller volume, reduces the area occupied by the surge suppression circuit, and is conducive to the miniaturization of the switching power supply and charger. The present application has the advantages of simple structure, low power consumption and high reliability, and improves the power density, cost performance and universality of the product.

[0053] Figure 2 This is a schematic diagram of the structure of a switching power supply provided by another embodiment of the present application. Figure 2 As shown, the switching power supply provided in this embodiment further includes an anti-electromagnetic interference circuit 160 connected between the surge suppression circuit 120 and the rectifier circuit on the basis of any of the above embodiments.

[0054] In this embodiment, anti-electromagnetic interference circuit 160 is used to suppress or reduce electromagnetic interference in the switching power supply circuit. Anti-electromagnetic interference circuit 160, also known as an EMI circuit, typically includes inductors, capacitors, resistors, etc. Capacitors filter out external electromagnetic interference introduced from power lines or other signal lines, and inductors suppress electromagnetic radiation, thereby protecting the switching power supply circuit from operating normally in complex electromagnetic environments.

[0055] Figure 3 This is a circuit diagram of a switching power supply provided in one embodiment of the present application. Figure 3 As shown, the switching power supply provided in this embodiment includes an input circuit 110 , a surge suppression circuit 120 , an anti-electromagnetic interference circuit 160 , a rectifier and filter tank circuit 130 , a DC-DC conversion circuit 140 and an output circuit 150 .

[0056] like Figure 3 As shown, in this embodiment, the input circuit 110 includes a first sub-input terminal and a second sub-input terminal, which are respectively connected to the L line (live line) and the N line (neutral line) of the mains power. The first end of the fuse F1 is connected to the first sub-input terminal, that is, directly connected to the L line (live line).

[0057] Surge suppression circuit 120 includes an NTC thermistor NTC1 and a temperature switch SW-TEMP connected in parallel. The first terminal of the NTC thermistor NTC1 is connected to the second sub-input terminal, that is, directly connected to the N line (neutral line). In some embodiments, the NTC thermistor NTC1 can also be connected to the L line (live line). In other embodiments, the NTC thermistor NTC1 can also be connected in series after the rectifier bridge in the switching power supply. This embodiment is only one possible implementation.

[0058] like Figure 3 As shown, in this embodiment, the anti-electromagnetic interference circuit 160 includes an inductor LF1 , a resistor RX1 , a resistor RX2 , a resistor RX3 , a resistor RX4 and a capacitor CX1 .

[0059] Specifically, the first input end of the inductor LF1 is connected to the second end of the fuse F1, and the second input end of the inductor LF1 is connected to the second end of the NTC thermistor NTC1; the resistor RX1 and the resistor RX2 are connected in series, the first end of the resistor RX1 is connected to the first output end of the inductor LF1, and the second end of the resistor RX2 is connected to the second output end of the inductor LF1; the resistor RX3 and the resistor RX4 are connected in series, the first end of the resistor RX3 is connected to the first output end of the inductor LF1, and the second end of the resistor RX4 is connected to the second output end of the inductor LF1; the first end of the capacitor CX1 is connected to the first output end of the inductor LF1, and the second end of the capacitor CX1 is connected to the second output end of the inductor LF1.

[0060] like Figure 3 As shown, in this embodiment, the rectifier-filtering energy storage circuit includes a rectifier BR1, an energy storage capacitor EC1, an inductor L4, an energy storage capacitor EC2 and a capacitor C18.

[0061] Specifically, the first end of the rectifier BR1 is connected to the first input end of the rectifier and filter energy storage circuit, that is, it is linked to the first end of the capacitor CX1, and the second end of the rectifier BR1 is connected to the second input end of the rectifier and filter energy storage circuit, that is, it is connected to the second end of the capacitor CX1; the first end of the energy storage capacitor EC1 is connected to the first output end of the rectifier BR1, and the second end of the energy storage capacitor EC1 is connected to the second output end of the rectifier BR1; the first end of the inductor L4 is connected to the first end of the energy storage capacitor EC1; the first end of the energy storage capacitor EC2 is connected to the second end of the inductor L4, and the second end of the energy storage capacitor EC2 is connected to the first preset voltage end; the first end of the capacitor C18 is connected to the first end of the energy storage capacitor EC2, and the second end of the capacitor C18 is connected to the first preset voltage end.

[0062] like Figure 3As shown, in this embodiment, the DC-DC conversion circuit 140 includes a transformer, an EMI filtering and absorbing capacitor, a synchronous rectification module, and energy storage capacitors EC5, EC6 and C13 connected in parallel.

[0063] Specifically, the first end of the transformer input winding is connected to the input end of the DC-DC conversion circuit 140; the EMI absorption capacitor is connected in parallel to the transformer input winding; the input end of the synchronous rectifier module is connected to the second end of the transformer output winding, and the output end of the synchronous rectifier module is connected to the second preset voltage end; the first end of the energy storage capacitor EC5 is connected to the first end of the transformer output winding and the output end of the DC-DC conversion circuit 140, and the second end of the energy storage capacitor EC5 is connected to the second preset voltage end.

[0064] In some embodiments, the synchronous rectification module includes a switch tube M1, a control chip U2, a resistor R19, a resistor R17, a capacitor C12, a resistor R18, a resistor R20, a capacitor C17, and a capacitor C18.

[0065] Specifically, the first end of the switch tube M1 is connected to the input end of the synchronous rectification module, the second end of the switch tube M1 is connected to the output end of the synchronous rectification module, and the control end of the switch tube M1 is connected to the GATE pin of the control chip U2; the first end of the resistor R19 is connected to the first end of the switch tube M1, and the second end of the resistor R19 is connected to the DESN pin of the control chip U2; the resistor R17 and the capacitor C12 are connected in series, the first end of the resistor R17 is connected to the first end of the switch tube M1, and the second end of the capacitor C12 is connected to the second end of the switch tube M1; the first end of the resistor R18 is connected to the REG pin of the control chip U2, the first end of the resistor R20 is connected to the TZ pin of the control chip U2, the first end of the capacitor C17 is connected to the VDD pin of the control chip U2, the first end of the capacitor C18 is connected to the VIN pin of the control chip U2, and the second ends of the resistor R18, the resistor R20, the capacitor C17 and the capacitor C18 are all connected to the second preset voltage end.

[0066] In some embodiments, the control chip U2 uses a power management chip model SY5239.

[0067] In some embodiments, the DC-DC converter circuit 140 further includes a power control module. The power control module includes a ferrite bead FB1, a control chip U1, a capacitor C11, a resistor R14, a resistor R15, a resistor R7, a capacitor C3, a resistor R8, a transformer auxiliary winding T1B, an energy storage capacitor EC3, a capacitor C5, a resistor R11, a diode D5, a resistor R9, a resistor R10, a capacitor C8, an optocoupler PC1B, a Zener diode ZD1, a resistor R12, and a capacitor C9.

[0068] Specifically, the first end of the magnetic bead FB1 is connected to the second end of the transformer input winding, and the second end of the magnetic bead FB1 is connected to at least one SW pin of the control chip U1; the first end of the capacitor C11 is connected to the second end of the magnetic bead FB1, and the second end of the capacitor C11 is connected to at least one CS pin of the control chip U1; the resistor R14 and the resistor R15 are connected in parallel, the first end of the resistor R14 is connected to the second end of the capacitor C11, and the second end of the resistor R14 is connected to the GND pin of the control chip U1 and the first preset voltage end.

[0069] A first end of resistor R7 is connected to the VDD pin of control chip U1; a first end of capacitor C3 is connected to the second end of resistor R7; a first end of resistor R8 is connected to the second end of capacitor C3; a first end of transformer auxiliary winding T1B is connected to the second end of resistor R8, and a second end of transformer auxiliary winding T1B is connected to the first preset voltage end.

[0070] The energy storage capacitor EC3 and the capacitor C5 are connected in parallel, the first end of the energy storage capacitor EC3 is connected to the first end of the resistor R7, and the second end of the energy storage capacitor EC3 is connected to the first preset voltage end; the first end of the resistor R11 is connected to the second end of the capacitor C5, and the resistor R11 is connected to the FEST pin of the control chip U1; the first end of the diode D5 is connected to the second end of the resistor R7, and the second end of the diode D5 is connected to the second end of the resistor R8.

[0071] A first end of the resistor R9 is connected to the second end of the diode D5; a first end of the resistor R10 is connected to the second end of the resistor R9, and the second end of the resistor R10 is connected to the first preset voltage end; a first end of the capacitor C8 is connected to the second end of the resistor R9 and the DMG pin of the control chip U1, and the second end of the capacitor C8 is connected to the first preset voltage end; the optocoupler PC1B and the Zener diode ZD1 are connected in parallel, and the second end of the optocoupler PC1B is connected to the first preset voltage end; a first end of the resistor R12 is connected to the first end of the optocoupler PC1B, and the second end of the resistor R12 is connected to the FB pin of the control chip U1; a first end of the capacitor C9 is connected to the second end of the resistor R12, and the second end of the capacitor C9 is connected to the first preset voltage end.

[0072] In some embodiments, the control chip U1 uses the PN8783 control chip, which integrates a current-mode controller, a high-voltage startup module, and a high-performance GaN FET, specifically designed for high-performance fast-charging switching power supplies. It supports a full input voltage range of 90 to 265V, an output power of 65W, and output voltages of 5V / 3A, 9V / 3A, 15V / 3A, and 20V / 3.25A, making it suitable for a wide range of applications.

[0073] like Figure 3As shown, in some embodiments, the DC-DC conversion circuit 140 further includes an RCD absorption module. The RCD absorption module includes a diode D3, a resistor R2, a resistor R3, a capacitor C1, a resistor R4, and a resistor R5.

[0074] Specifically, resistor R2, resistor R3 and capacitor C1 are connected in parallel, the first end of resistor R2 is connected to the first end of the transformer input winding; the first end of resistor R4 is connected to the second end of resistor R2; the first end of diode D3 is connected to the second end of resistor R4, and the second end of diode D3 is connected to the second end of magnetic bead FB1; the first end of resistor R5 is connected to the second end of capacitor C1, and the second end of resistor R5 is connected to the second end of resistor R4.

[0075] like Figure 3 As shown, in some embodiments, the switching power supply further includes a voltage regulation and feedback control circuit; the voltage regulation and feedback control circuit includes a resistor R24, a resistor R27, a switch tube M2, a resistor R26, a resistor R25, a resistor R21, an optocoupler PC1A, a voltage regulator chip U3, a capacitor C16, a resistor R22, a resistor R23, and a capacitor C17.

[0076] Specifically, the first end of the resistor R24 ​​is connected to the output circuit 150; the first end of the resistor R27 is connected to the second end of the resistor R24; the first end of the switch tube M2 is connected to the second end of the resistor R27, the second end of the switch tube M2 is connected to the second preset voltage end, and the control end of the switch tube M2 is used to obtain the external input adjustment signal; the resistor R26 and the resistor R25 are connected in parallel, the first end of the resistor R26 is connected to the second end of the resistor R24, and the second end of the resistor R26 is connected to the second preset voltage end; the first end of the resistor R21 is connected to the first end of the resistor R24; the first end of the optocoupler PC1A is connected to the resistor The first end of the voltage stabilizing chip U3 is connected to the second end of the optocoupler PC1A, the second end of the voltage stabilizing chip U3 is connected to the second preset voltage end, and the third end of the voltage stabilizing chip U3 is connected to the first end of the resistor R26; the first end of the capacitor C16 is connected to the first end of the resistor R24; the first end of the resistor R22 is connected to the second end of the capacitor C16, and the second end of the resistor R22 is connected to the first end of the voltage stabilizing chip U3; the resistor R23 and the capacitor C17 are connected in series, the first end of the resistor R23 is connected to the second end of the resistor R22, and the second end of the capacitor C17 is connected to the second end of the resistor R24.

[0077] In summary, the switching power supply and the charger including the switching power supply provided by the embodiments of the present application include an input circuit, a surge suppression circuit, a rectifier filter energy storage circuit, a DC-DC conversion circuit, and an output circuit. The surge suppression circuit includes an NTC thermistor and a temperature switch connected in parallel, and the operating temperature of the temperature switch is greater than or equal to the surface temperature of the NTC thermistor when it is in operation, and the temperature switch is in a normally open state. The present application uses the temperature switch to automatically close and short-circuit the NTC thermistor when the temperature of the NTC thermistor or the product to which it is applied rises, and automatically open and restore the NTC thermistor to its working state when the temperature of the NTC thermistor drops. This achieves the goal of suppressing the inrush current in the switching power supply circuit while effectively reducing the power loss caused by the additional temperature rise of the NTC thermistor. In addition, compared with existing switching circuits such as relays, the temperature switch has a smaller volume, reduces the area occupied by the surge suppression circuit, and is conducive to the miniaturization of the switching power supply and charger. The present application has the advantages of simple structure, low power consumption and high reliability, and improves the power density, cost performance and universality of the product.

[0078] Another embodiment of the present application provides a charger, characterized by including an adapter for converting AC power to DC power, and a data cable connected to the adapter. The adapter, which converts AC power to DC power, includes the switching power supply described in any of the above embodiments and has the advantages of the data cable described in any of the above embodiments, which will not be further described here.

[0079] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can make several simple deductions, modifications or replacements based on the ideas of the present application without departing from the scope of protection of the purpose of the present application and the claims. All of these are within the protection of the present application.

Claims

1. A switching power supply, characterized in that: include: An input circuit, used for obtaining an externally inputted AC input voltage; a surge suppression circuit, connected to the input circuit, for suppressing surge current in the circuit; a rectifier filtering energy storage circuit, connected to the surge suppression circuit, for converting the AC input voltage into a DC voltage and performing filtering; A DC-DC conversion circuit is connected to the rectifier and filter energy storage circuit, and is used to convert the rectified and filtered DC voltage into a target DC output voltage; an output circuit, connected to the DC-DC conversion circuit, and configured to output the target DC output voltage; The input circuit is connected to a fuse F1; the surge suppression circuit includes an NTC thermistor and a temperature switch connected in parallel; and the operating temperature of the temperature switch is greater than or equal to the surface temperature of the NTC thermistor when working, and the temperature switch is in a normally open state.

2. The switching power supply according to claim 1, characterized in that: It also includes an anti-electromagnetic interference circuit connected between the surge suppression circuit and the rectifier circuit, which is used to suppress or reduce electromagnetic interference in the switching power supply circuit.

3. The switching power supply according to claim 2, characterized in that: The anti-electromagnetic interference circuit includes an inductor LF1, a resistor RX1, a resistor RX2, a resistor RX3, a resistor RX4 and a capacitor CX1; The first input end of the inductor LF1 is connected to the second end of the fuse F1, and the second input end of the inductor LF1 is connected to one end of the NTC thermistor; the resistor RX1 and the resistor RX2 are connected in series, the first end of the resistor RX1 is connected to the first output end of the inductor LF1, and the second end of the resistor RX2 is connected to the second output end of the inductor LF1; the resistor RX3 and the resistor RX4 are connected in series, the first end of the resistor RX3 is connected to the first output end of the inductor LF1, and the second end of the resistor RX4 is connected to the second output end of the inductor LF1; the first end of the capacitor CX1 is connected to the first output end of the inductor LF1, and the second end of the capacitor CX1 is connected to the second output end of the inductor LF1.

4. The switching power supply according to claim 1, wherein: The rectifier filtering energy storage circuit includes a rectifier BR1, an energy storage capacitor EC1, an inductor L4, an energy storage capacitor EC2 and a capacitor C18; The first end of the rectifier BR1 is connected to the first input end of the rectifier and filter energy storage circuit, and the second end of the rectifier BR1 is connected to the second input end of the rectifier and filter energy storage circuit; the first end of the energy storage capacitor EC1 is connected to the first output end of the rectifier BR1, and the second end of the energy storage capacitor EC1 is connected to the second output end of the rectifier BR1; the first end of the inductor L4 is connected to the first end of the energy storage capacitor EC1; the first end of the energy storage capacitor EC2 is connected to the second end of the inductor L4, and the second end of the energy storage capacitor EC2 is connected to the first preset voltage end; the first end of the capacitor C18 is connected to the first end of the energy storage capacitor EC2, and the second end of the capacitor C18 is connected to the first preset voltage end.

5. The switching power supply according to claim 1, wherein: The DC-DC conversion circuit includes a transformer, an EMI absorption capacitor C2, a synchronous rectification module, and parallel energy storage capacitors EC5, EC6 and C13; the first end of the transformer input winding is connected to the input end of the DC-DC conversion circuit; the EMI absorption capacitor C2 is connected in parallel to the transformer input winding; the input end of the synchronous rectification module is connected to the second end of the transformer output winding, and the output end of the synchronous rectification module is connected to the second preset voltage end; the first end of the energy storage capacitor EC5 is connected to the first end of the transformer output winding and the output end of the DC-DC conversion circuit, and the second end of the energy storage capacitor EC5 is connected to the second preset voltage end.

6. The switching power supply according to claim 5, characterized in that: The synchronous rectification module includes a switch tube M1, a control chip U2, a resistor R19, a resistor R17, a capacitor C12, a resistor R18, a resistor R20, a capacitor C17 and a capacitor C18; The first end of the switch tube M1 is connected to the input end of the synchronous rectifier module, the second end of the switch tube M1 is connected to the output end of the synchronous rectifier module, and the control end of the switch tube M1 is connected to the GATE pin of the control chip U2; the first end of the resistor R19 is connected to the first end of the switch tube M1, and the second end of the resistor R19 is connected to the DESN pin of the control chip U2; the resistor R17 and the capacitor C12 are connected in series, the first end of the resistor R17 is connected to the first end of the switch tube M1, and the second end of the capacitor C12 is connected to the second end of the switch tube M1; the first end of the resistor R18 is connected to the REG pin of the control chip U2, the first end of the resistor R20 is connected to the TZ pin of the control chip U2, the first end of the capacitor C17 is connected to the VDD pin of the control chip U2, the first end of the capacitor C18 is connected to the VIN pin of the control chip U2, and the second ends of the resistor R18, the resistor R20, the capacitor C17, and the capacitor C18 are all connected to the second preset voltage end.

7. The switching power supply according to claim 5, characterized in that: The DC-DC conversion circuit also includes a power control module; the power control module includes a magnetic bead FB1, a control chip U1, a capacitor C11, a resistor R14, a resistor R15, a resistor R7, a capacitor C3, a resistor R8, a transformer auxiliary winding T1B, an energy storage capacitor EC3, a capacitor C5, a resistor R11, a diode D5, a resistor R9, a resistor R10, a capacitor C8, an optocoupler PC1B, a voltage regulator diode ZD1, a resistor R12, and a capacitor C9; The first end of the magnetic bead FB1 is connected to the second end of the transformer input winding, and the second end of the magnetic bead FB1 is connected to at least one SW pin of the control chip U1; the first end of the capacitor C11 is connected to the second end of the magnetic bead FB1, and the second end of the capacitor C11 is connected to at least one CS pin of the control chip U1; the resistor R14 and the resistor R15 are connected in parallel, the first end of the resistor R14 is connected to the second end of the capacitor C11, and the second end of the resistor R14 is connected to the GND pin of the control chip U1 and the first preset voltage terminal; The first end of the resistor R7 is connected to the VDD pin of the control chip U1; the first end of the capacitor C3 is connected to the second end of the resistor R7; the first end of the resistor R8 is connected to the second end of the capacitor C3; the first end of the transformer auxiliary winding T1B is connected to the second end of the resistor R8, and the second end of the transformer auxiliary winding T1B is connected to the first preset voltage terminal; The energy storage capacitor EC3 and the capacitor C5 are connected in parallel, the first end of the energy storage capacitor EC3 is connected to the first end of the resistor R7, and the second end of the energy storage capacitor EC3 is connected to the first preset voltage end; the first end of the resistor R11 is connected to the second end of the capacitor C5, and the resistor R11 is connected to the FEST pin of the control chip U1; the first end of the diode D5 is connected to the second end of the resistor R7, and the second end of the diode D5 is connected to the second end of the resistor R8; The first end of the resistor R9 is connected to the second end of the diode D5; the first end of the resistor R10 is connected to the second end of the resistor R9, and the second end of the resistor R10 is connected to the first preset voltage end; the first end of the capacitor C8 is connected to the second end of the resistor R9 and the DMG pin of the control chip U1, and the second end of the capacitor C8 is connected to the first preset voltage end; the optocoupler PC1B and the Zener diode ZD1 are connected in parallel, and the second end of the optocoupler PC1B is connected to the first preset voltage end; the first end of the resistor R12 is connected to the first end of the optocoupler PC1B, and the second end of the resistor R12 is connected to the FB pin of the control chip U1; the first end of the capacitor C9 is connected to the second end of the resistor R12, and the second end of the capacitor C9 is connected to the first preset voltage end.

8. The switching power supply according to claim 7, characterized in that: The DC-DC conversion circuit further includes an RCD absorption module; the RCD absorption module includes a diode D3, a resistor R2, a resistor R3, a capacitor C1, a resistor R4 and a resistor R5; The resistor R2, the resistor R3 and the capacitor C1 are connected in parallel, the first end of the resistor R2 is connected to the first end of the transformer input winding; the first end of the resistor R4 is connected to the second end of the resistor R2; the first end of the diode D3 is connected to the second end of the resistor R4, and the second end of the diode D3 is connected to the second end of the magnetic bead FB1; the first end of the resistor R5 is connected to the second end of the capacitor C1, and the second end of the resistor R5 is connected to the second end of the resistor R4.

9. The switching power supply according to claim 1, wherein: It also includes a voltage regulation and feedback control circuit; the voltage regulation and feedback control circuit includes a resistor R24, a resistor R27, a switch tube M2, a resistor R26, a resistor R25, a resistor R21, an optocoupler PC1A, a voltage regulator chip U3, a capacitor C16, a resistor R22, a resistor R23, and a capacitor C17; The first end of the resistor R24 ​​is connected to the output circuit; the first end of the resistor R27 is connected to the second end of the resistor R24; the first end of the switch tube M2 is connected to the second end of the resistor R27, the second end of the switch tube M2 is connected to the second preset voltage end, and the control end of the switch tube M2 is used to obtain the external input adjustment signal; the resistor R26 and the resistor R25 are connected in parallel, the first end of the resistor R26 is connected to the second end of the resistor R24, and the second end of the resistor R26 is connected to the second preset voltage end; the first end of the resistor R21 is connected to the first end of the resistor R24; the first end of the optocoupler PC1A is connected to the The first end of the voltage stabilizing chip U3 is connected to the second end of the optocoupler PC1A, the second end of the voltage stabilizing chip U3 is connected to the second preset voltage end, and the third end of the voltage stabilizing chip U3 is connected to the first end of the resistor R26; the first end of the capacitor C16 is connected to the first end of the resistor R24; the first end of the resistor R22 is connected to the second end of the capacitor C16, and the second end of the resistor R22 is connected to the first end of the voltage stabilizing chip U3; the resistor R23 and the capacitor C17 are connected in series, the first end of the resistor R23 is connected to the second end of the resistor R22, and the second end of the capacitor C17 is connected to the second end of the resistor R24.

10. A charger, characterized in that: comprising an adapter for converting alternating current into direct current, and a data cable connected to the adapter; Wherein, the adapter comprises the switching power supply according to any one of claims 1-9.

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