A transformer device, a switching power supply, and a power adapter

Abstract

The present invention discloses a transformer device, a switching power supply and a power adapter. The device includes: a primary winding module, a secondary winding and a shielding layer; the primary winding module includes: a first part of the primary winding and a second part of the primary winding; wherein, the first part of the primary winding, the secondary winding, the shielding layer and the second part of the primary winding are arranged in a set direction in sequence; the first part of the primary winding is configured to be connected to a DC bus; the second part of the primary winding is configured to be connected to a main power device of the switching power supply. The solution of the present invention can solve the problem that the addition of an auxiliary winding to a high-frequency transformer increases the circuit complexity, and achieve the effect of simplifying the circuit structure of the high-frequency transformer.

Description

Technical Field

[0001] The present invention belongs to the technical field of electronic circuits, and particularly relates to a transformer device, a switching power supply, and a power adapter, and more particularly to a high-frequency transformer, a switching power supply circuit, and a power adapter using the same. Background Art

[0002] Some high-frequency transformers of switching power supplies and power adapters have auxiliary windings, and the auxiliary windings and their circuits increase the circuit complexity.

[0003] The above content is only used to assist in understanding the technical solution of the present invention, and does not represent an admission that the above content is prior art. Summary of the Invention

[0004] An object of the present invention is to provide a transformer device, a switching power supply, and a power adapter to solve the problem that the presence of an auxiliary winding in a high-frequency transformer increases the circuit complexity, and achieve the effect of simplifying the circuit structure of the high-frequency transformer.

[0005] The present invention provides a transformer device, including: a primary winding module, a secondary winding, and a shielding layer; the primary winding module includes: a first part of the primary winding and a second part of the primary winding; wherein, the first part of the primary winding, the secondary winding, the shielding layer, and the second part of the primary winding are arranged in sequence in a set direction; the first part of the primary winding is configured to connect to a DC bus; the second part of the primary winding is configured to connect to a main power device of a switching power supply.

[0006] In some embodiments, it further includes: a transformer bobbin; the first part of the primary winding, the secondary winding, the shielding layer, and the second part of the primary winding are wound on the transformer bobbin; and an insulating tape is used for insulation between adjacent parts of the first part of the primary winding, the secondary winding, the shielding layer, and the second part of the primary winding.

[0007] In some embodiments, the first part of the primary winding is wound only one layer and is fully covered with a tight winding or a loose winding method; the first end of the first part of the primary winding is configured to connect to the positive pole of the DC bus; the second end of the first part of the primary winding is configured to connect to an intermediate node of the transformer device.

[0008] In some embodiments, the secondary winding can determine at least one of the number of winding strands, wire diameter, and number of turns according to at least one of the target number of output paths, target output current, and target output voltage.

[0009] In some embodiments, the shielding layer includes a shielding winding; the shielding winding is wound with any one of metal foil, metal strip, and metal wire, and can be wound in a multi-strand parallel winding manner when one layer is fully wound; the shielding winding is configured to be connected to the positive pole of the DC bus, and short-circuit prevention is provided at the head and tail ends of the shielding winding.

[0010] In some embodiments, the second part of the primary winding uses the same wire material as the first part of the primary winding, is wound in two layers, and is fully wound in the whole layer; the first end of the second part of the primary winding is configured to be connected to the intermediate node of the transformer device; the second end of the second part of the primary winding is configured to be connected to the drain of the main power device of the switching power supply.

[0011] Matched with the above device, on the other hand, the present invention provides a switching power supply, including: a rectifier filter circuit, a high-frequency transformer, a main control unit, an AC low-impedance bypass circuit, a freewheeling and absorption circuit, and an output filter circuit; the main control unit includes: a main switching device and a control system; the high-frequency transformer uses the above-mentioned transformer device; wherein, the rectifier filter circuit is connected to the primary winding of the transformer device and the main control unit; the secondary winding of the transformer device is connected to the output filter circuit after passing through the freewheeling and absorption circuit; the control system takes power from the secondary side of the transformer device at the first output voltage; takes power from the primary side of the transformer device at the second output voltage; the output accuracy of the first output voltage is greater than the output accuracy of the second output voltage.

[0012] In some embodiments, the rectifier filter circuit includes: a rectifier bridge and a filter circuit; the rectifier bridge and the filter circuit are cooperatively arranged; the filter circuit includes: two differential-mode inductors and two capacitors; the two differential-mode inductors are arranged in parallel, and the two capacitors are arranged in parallel at the ends of the two differential-mode inductors.

[0013] In some embodiments, the rectifier bridge is arranged between the two capacitors and on any side of the two differential-mode inductors, or the rectifier bridge is arranged on the same side of the two capacitors; among the two capacitors, the capacitor located on the AC side is a film capacitor, and the capacitor located on the DC side is an electrolytic capacitor.

[0014] Matched with the above switching power supply, on the other hand, the present invention provides a power adapter, including: the above-mentioned switching power supply.

[0015] Thus, the solution of the present invention solves the problem that the high-frequency transformer with an auxiliary winding increases the circuit complexity by enabling the control circuit of the main power device to take power from the DC bus or the drain, and sets a high-frequency transformer without an auxiliary winding, achieving the effect of simplifying the circuit structure of the high-frequency transformer.

[0016] Other features and advantages of the present invention will be set forth in the following description, and in part will be obvious from the description, or may be learned by practice of the present invention.

[0017] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Description of the Drawings

[0018] Figure 1 It is a schematic structural diagram of an embodiment of a rectifying and filtering circuit;

[0019] Figure 2 It is a schematic structural diagram of an embodiment of a transformer device of the present invention;

[0020] Figure 3 It is a schematic structural diagram of an embodiment of a switching power supply circuit;

[0021] Figure 4 It is a schematic structural diagram of an embodiment of a transformer winding;

[0022] Figure 5 It is a schematic diagram of the first test result of conducted EMI.

[0023] In combination with the accompanying drawings, the reference numerals in the embodiments of the present invention are as follows:

[0024] 1 - Transformer skeleton; 2 - Insulating tape. Detailed Embodiments

[0025] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0026] According to an embodiment of the present invention, a transformer device is provided. Refer to Figure 1 The schematic structural diagram of an embodiment of the device of the present invention as shown. The transformer device includes a primary winding module, a secondary winding (i.e., an output winding), and a shielding layer. The primary winding module includes a first part of the primary winding and a second part of the primary winding.

[0027] Among them, the first part of the primary winding, the secondary winding, the shielding layer, and the second part of the primary winding are arranged in sequence in a set direction, for example, they can be arranged from the outside to the inside in sequence. The first part of the primary winding is configured to connect to the positive pole of the DC bus, that is, the static point of the circuit; the second part of the primary winding is configured to connect to the main power device of the switching power supply, such as connecting to the drain of the main power device of the switching power supply.

[0028] For example: The high-frequency transformer has no auxiliary winding, only a primary winding and an output winding. The outermost layer of the transformer is the first part of the primary winding, which is only wound in one layer and connected to the static point of the DC bus. From the outside to the inside in sequence are the first part of the primary winding, the output winding, the shielding layer, and the second part of the primary winding. The second part of the primary winding is connected to the main power device.

[0029] Thus, by making the transformer structure without an auxiliary winding, the transformer structure is simplified, production is more convenient and the cost is lower.

[0030] In some embodiments, it further includes: a transformer bobbin 1. The first part of the primary winding, the secondary winding, the shielding layer, and the second part of the primary winding are wound on the transformer bobbin 1. And an insulating layer is provided between adjacent parts of the first part of the primary winding, the secondary winding, the shielding layer, and the second part of the primary winding, such as insulating with an insulating tape 2.

[0031] For example: The primary winding is the primary side winding, and the secondary winding is the secondary side winding. In the transformer winding structure, from the outside to the inside in sequence are the first part of the primary winding, the secondary winding, the shielding winding, and the second part of the primary winding. The windings are wound on the transformer bobbin 1, and the insulating tape 2 is used for insulation between the windings. Usually, the number of turns of the tape is 1 - 3 turns. Dividing the primary winding into two parts, this structure can reduce the leakage inductance of the transformer to a certain extent.

[0032] In some embodiments, the first part of the primary winding is only wound in one layer and is fully covered with the whole layer in a close-wound or sparse-wound manner. The first end of the first part of the primary winding is configured to connect to the positive pole of the DC bus. The second end of the first part of the primary winding is configured to connect to the intermediate node of the transformer device.

[0033] That is to say, the first part of the primary winding is only wound in one layer and is fully covered with the whole layer in a close-wound or sparse-wound manner. One end of the first part of the primary winding is connected to the positive pole of the DC bus, and the other end is connected to the intermediate node of the transformer. The first part of the primary winding is on the outermost layer of the transformer and has fewer layers than the second part of the primary winding, which is equivalent to shielding most of the interference of the primary winding to a certain extent through the intermediate secondary winding. The first part of the primary winding is connected to the "static point" of the circuit because the interference of the "static point" is smaller and there is no need to place it in the inner layer for shielding.

[0034] In some embodiments, the secondary winding is capable of determining at least one of the number of strands, wire diameter, and number of turns based on at least one of the target number of output paths, target output current, and target output voltage.

[0035] For example: The secondary winding determines the number of strands, wire diameter, and number of turns based on the number of output paths, current, and voltage. The secondary winding needs to be determined according to the actual circuit. Among them, the number of strands of the secondary winding refers to how many winding wires are used for parallel winding of the secondary winding.

[0036] In some embodiments, the shielding layer includes a shielding winding. The shielding winding is wound with any one of metal foil, metal tape, and metal wire. When winding a full layer, a multi-strand parallel winding method can be used. The shielding winding is configured to be connected to the positive pole of the DC bus, and short-circuit prevention settings are made at the head and tail ends of the shielding winding.

[0037] For example: The shielding winding is wound with metal foil, metal tape, or metal wire. When winding a full layer, a multi-strand parallel winding form can be used. The shielding winding is connected to the positive end of the DC bus. The head and tail ends of the shielding winding cannot be short-circuited. The shielding winding is connected to the "static point" of the circuit to discharge the coupled interference. Short-circuiting the head and tail cannot form an effective shield.

[0038] In some embodiments, the second part of the primary winding uses the same wire material as the first part of the primary winding, winds two layers, and winds the entire layer. The first end of the second part of the primary winding is configured to be connected to the intermediate node of the transformer device. The second end of the second part of the primary winding is configured to be connected to the drain of the main power device of the switching power supply. Specifically, the primary winding is wound in two parts, and the inner second part winds two layers.

[0039] For example: The second part of the primary winding uses the same wire material as the first part. Usually, it winds an integer number of layers. The number of layers and turns of the second part do not have to be close to or equal to those of the first part. One end of the second part of the primary winding is connected to the intermediate node of the transformer, and the other end is connected to the main power device. The second part of the primary winding is on the innermost side of the transformer and is connected to the point on the circuit where du / dt is relatively large. The outer winding can effectively shield these interferences.

[0040] Verified by a large number of tests, by adopting the technical solution of the present invention, by taking power for the control circuit of the main power device from the DC bus or the drain, and setting a high-frequency transformer without an auxiliary winding, a differential-mode inductor can be used to meet the electromagnetic compatibility related tests, and the differential-mode inductor is convenient for automated production and improves production efficiency.

[0041] According to an embodiment of the present invention, a switching power supply corresponding to a transformer device is further provided. The switching power supply may include: a rectifier and filter circuit, a high-frequency transformer, a main control unit, an AC low-impedance bypass circuit, a freewheeling and absorption circuit, and an output filter circuit. The main control unit includes: a main switching device and a control system. The high-frequency transformer employs the transformer device described above.

[0042] Among them, the rectifier and filter circuit is connected to the primary winding of the transformer device and the main control unit. The secondary winding of the transformer device is connected to the output filter circuit via the freewheeling and absorption circuit.

[0043] For example: The switching power supply circuit includes: a rectifier and filter circuit, a freewheeling and absorption circuit, a high-frequency transformer, an AC low-impedance bypass circuit, a main switching device and its control circuit, and an output filter circuit. The AC power input is connected to the rectifier and filter circuit, and the rectifier and filter circuit is connected to the circuit composed of the primary winding of the high-frequency transformer and the main switching device in series. The secondary winding of the high-frequency transformer is connected to the freewheeling and absorption circuit, the freewheeling and absorption circuit is connected to the output filter circuit, and the output filter circuit is connected to the load. The function of the AC low-impedance bypass circuit is to provide a bypass path for common-mode interference, and generally consists of one or more series capacitors.

[0044] The control system takes power from the secondary side of the transformer device at a first output voltage. At a second output voltage, it takes power from the primary side of the transformer device. The output accuracy of the first output voltage is greater than that of the second output voltage. The first output voltage is the output voltage with higher requirements for output accuracy. The second output voltage is the output voltage with lower requirements for output accuracy.

[0045] For example: The transformer has no auxiliary winding. The control circuit can be powered by the DC bus or the drain voltage. There are two ways to take power, namely taking power from the DC bus and taking power from the drain. There are two feedback methods. That is, if the requirements for the output voltage accuracy are high, secondary side feedback is adopted, isolated by a transformer or an optocoupler. If the requirements for the output voltage accuracy are not high, primary side feedback is adopted.

[0046] Thus, by enabling the control circuit of the main power device to take power from the DC bus or the drain and the transformer having no auxiliary winding, the problems of complex circuit, many loop components, and high cost caused by the transformer having an auxiliary winding can be solved, and the circuit structure can be simplified.

[0047] In some embodiments, the rectifier and filter circuit includes: a rectifier bridge and a filter circuit; the rectifier bridge and the filter circuit are arranged in cooperation. The filter circuit includes: two differential-mode inductors and two capacitors. The two differential-mode inductors are arranged in parallel, and the two capacitors are arranged in parallel at the ends of the two differential-mode inductors.

[0048] For example, the rectifier filter circuit is composed of a rectifier bridge and a filter circuit. The filter circuit consists of two differential-mode inductors and two capacitors. The inductance values of the two differential-mode inductors can be the same or different, and the capacitance values of the two capacitors can also be the same or different. A common-mode inductor is used, but the common-mode inductor cannot be inserted by machine. The solution of the present invention uses a differential-mode inductor instead of a common-mode inductor, which can realize automated production. The capacitor located on the AC side is a film capacitor, and the capacitor located on the DC side is an electrolytic capacitor. The entire structure functions as a rectifier filter, and the rectifier bridge functions to convert AC to DC. At each position, the first capacitor C1, the second capacitor C2, the first inductor L1, and the second inductor L2 can suppress the electromagnetic interference of the power grid.

[0049] In some embodiments, the rectifier bridge is disposed between the two capacitors and on either side of the two differential-mode inductors, or the rectifier bridge is disposed on the same side of the two capacitors. Among the two capacitors, the capacitor located on the AC side is a film capacitor, and the capacitor located on the DC side is an electrolytic capacitor.

[0050] For example, the rectifier filter circuit can be divided into 4 structures according to whether the filter components are located on the AC or DC side. Among them, the capacitor located on the AC side is a film capacitor, and the capacitor located on the DC side is an electrolytic capacitor. The function of the capacitor on the AC side is to filter out differential-mode interference, and the function of the capacitor on the DC side is to provide and stabilize the DC voltage through charging and discharging. Since the functions are different, they are selected according to the characteristics of the capacitors.

[0051] Since the processing and functions implemented by the switching power supply in this embodiment are basically corresponding to the embodiments, principles, and examples of the foregoing device, for the details not described in the description of this embodiment, reference can be made to the relevant descriptions in the foregoing embodiments, and details will not be repeated here.

[0052] Through a large number of experimental verifications, by adopting the technical solution of the present invention, the driving and control circuit obtains power from the DC bus or the drain, and the transformer has no auxiliary winding, making the transformer smaller in volume, lower in leakage inductance, and simpler in circuit structure.

[0053] According to an embodiment of the present invention, there is also provided a power adapter corresponding to the switching power supply. The power adapter may include: the above-mentioned switching power supply.

[0054] Switching power supplies and power adapters convert the strong power from the power grid into the weak power used by electronic devices, and are key core components of many electronic devices. To meet the requirements of electromagnetic compatibility testing, in some solutions, the vast majority of switching power supplies and power adapters use common-mode inductors as filtering devices. However, common-mode inductors cannot be inserted by machines, which is not conducive to automated production and increases labor costs and working hours. In some solutions, the high-frequency transformers of the vast majority of switching power supplies and power adapters have auxiliary windings for the control of main power devices and output voltage feedback. The auxiliary windings and their circuits increase the circuit complexity, raise the product cost, and also increase the volume and leakage inductance of the transformer, increase the voltage stress of the main power device, and reduce the reliability of the switching power supply and power adapter.

[0055] In some embodiments, the solution of the present invention proposes a switching power supply circuit that can use two differential-mode inductors instead of a common-mode inductor and has no auxiliary winding in the high-frequency transformer, which can be applied to a power adapter.

[0056] In the solution of the present invention, the main circuit uses differential-mode inductors for filtering and has no common-mode inductor;

[0057] In the solution of the present invention, through the special design of the transformer winding, using differential-mode inductors to replace common-mode inductors can also meet the electromagnetic compatibility testing, which can solve the problem that common-mode inductors are not conducive to automated production because they cannot be inserted by machines, thus facilitating automated production and improving production efficiency. That is to say, in the solution of the present invention, through the special design of the transformer winding, the problem that the traditional filtering circuit using common-mode inductors cannot be inserted by machines is solved. Using differential-mode inductors can meet the relevant electromagnetic compatibility tests, and differential-mode inductors are convenient for automated production and improve production efficiency.

[0058] In the solution of the present invention, the drive and control circuit takes power from the DC bus or the drain, and the transformer has no auxiliary winding. Specifically, in the solution of the present invention, the high-frequency transformer only has a primary winding and an output winding; the outermost layer of the transformer is the first part of the primary winding, which is only wound in one layer and connected to the static point of the DC bus; from the outside to the inside are the first part of the primary winding, the output winding, the shielding layer, and the second part of the primary winding; the second part of the primary winding is connected to the main power device.

[0059] In the solution of the present invention, the control circuit of the main power device takes power from the DC bus or the drain, and the transformer has no auxiliary winding, which can solve the problems of complex circuit, many circuit components, and high cost caused by the transformer having an auxiliary winding, and simplifies the circuit structure. That is to say, in the solution of the present invention, the control circuit of the main power device uses power taken from the DC bus or the drain, solving the problem of the traditional transformer requiring an auxiliary winding and having a complex circuit structure, making the transformer smaller in volume, lower in leakage inductance, and simpler in circuit structure.

[0060] In some specific embodiments, it can be combinedFigures 1 to 5 The example shown below exemplarily illustrates the specific implementation process of the solution of the present invention.

[0061] Figure 2 It is a schematic structural diagram of an embodiment of a switching power supply circuit. As Figure 2 shown, the switching power supply circuit includes: a rectifier filter circuit, a freewheeling and absorption circuit, a high-frequency transformer, an AC low-impedance bypass circuit, a main switch device and its control circuit, and an output filter circuit. The AC power input is connected to the rectifier filter circuit, and the rectifier filter circuit is connected to a circuit composed of the primary winding of the high-frequency transformer and the main switch device in series. The secondary winding of the high-frequency transformer is connected to the freewheeling and absorption circuit, the freewheeling and absorption circuit is connected to the output filter circuit, and the output filter circuit is connected to the load.

[0062] In Figure 2 the example shown, the transformer has no auxiliary winding. There are two ways to obtain power, namely, taking power from the DC bus and taking power from the drain. There are two feedback methods. That is, if high precision of the output voltage is required, secondary-side feedback is adopted, isolated by a transformer or an optocoupler; if low precision of the output voltage is required, primary-side feedback is adopted.

[0063] In Figure 2 the example shown, the function of the AC low-impedance bypass circuit is to provide a bypass path for common-mode interference, and generally consists of one or more series capacitors. In particular, in this embodiment, 2 2.2 nF ceramic capacitors are connected in series.

[0064] In Figure 2 the example shown, the main power device and its control circuit can be integrated on one chip or discrete devices can be used. As Figure 2 shown, the control circuit can be powered by the DC bus or the drain voltage. There are two feedback methods for the output voltage. The commonly used one is secondary-side feedback, isolated by a transformer or an optocoupler; if low precision of the output voltage is required, primary-side feedback can also be adopted.

[0065] Figure 3 It is a schematic structural diagram of an embodiment of a rectifier filter circuit. As Figure 3 shown, the rectifier filter circuit is composed of a rectifier bridge and a filter circuit. The filter circuit is composed of two differential-mode inductors and two capacitors. The inductance values of the two differential-mode inductors can be the same or different, and the capacitance values of the two capacitors can also be the same or different.

[0066] In Figure 3 the example shown, a common-mode inductor is adopted, but the common-mode inductor cannot be inserted by machine. The solution of the present invention uses a differential-mode inductor instead of a common-mode inductor, which can realize automated production. The capacitor on the AC side is selected as a thin-film capacitor, and the capacitor on the DC side is selected as an electrolytic capacitor. The rectifier bridge can be placed as Figure 3Any position shown. The entire structure functions as a rectifier filter, and the rectifier bridge functions to convert AC to DC; at each position, the first capacitor C1, the second capacitor C2, the first inductor L1, and the second inductor L2 can function to suppress electromagnetic interference from the power grid.

[0067] Generally, in the solution of the present invention, the rectifier filter circuit can be divided into 4 structures as shown according to whether the filtering components are located on the AC or DC side. Among them, film capacitors are selected for the capacitors located on the AC side, and electrolytic capacitors are selected for the capacitors located on the DC side. Figure 3 shown, where film capacitors are selected for the capacitors located on the AC side, and electrolytic capacitors are selected for the capacitors located on the DC side.

[0068] Among them, the Figure 3 4th structure in is adopted. Among them, both of the two common-mode inductors are I-shaped inductors of 220 uH, and the first capacitor C1 and the second inductor C2 are aluminum electrolytic capacitors of 10 F / 400V and 33 F / 400V respectively.

[0069] In some embodiments, the transformer winding structure is as shown in Figure 1 shown. The primary winding is the original side winding, and the secondary winding is the secondary side winding. In the transformer winding structure, from the outside to the inside are the first part of the primary winding, the secondary winding, the shielding winding, and the second part of the primary winding. The windings are wound on the transformer skeleton 1, and insulating tape 2 is used for insulation between the windings. Usually, the number of tape turns is 1 - 3 turns.

[0070] Among them, the first part of the primary winding is only wound in one layer, and the whole layer is covered in a closely wound or sparsely wound manner. One end of the first part of the primary winding is connected to the positive pole of the DC bus, and the other end is connected to the middle node of the transformer.

[0071] The number of strands, wire diameter, and number of turns of the secondary winding are determined according to the number of output circuits, current, and voltage.

[0072] The shielding winding is wound with metal foil, metal tape or metal wire, wound in one layer, and can be in the form of multiple strands wound together; the shielding winding is connected to the positive end of the DC bus, and the head and tail of the shielding winding cannot be short-circuited.

[0073] The second part of the primary winding uses the same wire as the first part, usually wound in an integer number of layers. The number of layers and turns of the second part do not have to be close to or equal to those of the first part; one end of the second part of the primary winding is connected to the middle node of the transformer, and the other end is connected to the main power device.

[0074] Particularly, in one embodiment, the number of output circuits is 1, the wire diameter of the secondary winding is 0.4 mm, 2 strands are wound together, and wound in 2 layers; the wire diameter of the first part of the primary winding is 0.3 mm, single strand wound in one layer; the wire diameter of the second part of the primary winding is 0.3 mm, single strand wound in 2 layers; the wire diameter of the shielding winding is 0.18 mm, 4 strands are wound together, and wound in one layer.

[0075] In the solution of the present invention, the overall circuit is relatively simple, facilitating the later PCB layout. The device selection is conducive to automated assembly, and while ensuring a low-cost control circuit, excellent EMC performance can be guaranteed. Figure 4 The measured results of the conducted EMI of the switching power supply circuit adopting the solution of this embodiment show that the margin is higher than 7.54 dB in the frequency band of 150 kHz - 30 MHz, fully meeting the national standard requirements.

[0076] Figure 4 And Figure 5 To show the technical effects and advantages brought by the solution of the present invention applied in a typical circuit, that is, it has good conducted EMI performance; the transformer structure has no auxiliary winding, simplifying the transformer structure, making production more convenient and with lower cost.

[0077] Since the processing and functions implemented by the method of this embodiment basically correspond to the embodiments, principles and examples of the foregoing switching power supply, for the details not described in the description of this embodiment, reference can be made to the relevant descriptions in the foregoing embodiments, and no further elaboration will be made here.

[0078] Verified by a large number of tests, by adopting the technical solution of this embodiment, a switching power supply circuit with two differential-mode inductors replacing the common-mode inductor and no auxiliary winding in the high-frequency transformer, when applied to a power adapter, can simplify the circuit structure and improve production efficiency.

[0079] In summary, it is easy for those skilled in the art to understand that, on the premise of no conflict, the above-mentioned advantageous ways can be freely combined and superimposed.

[0080] The above are only the embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, various changes and modifications can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the scope of the claims of the present invention.

Claims

1. A transformer device, characterized in that, Applied to high-frequency transformers; The transformer device includes: a primary winding module, a secondary winding, and a shielding layer; the primary winding module includes: a first part of the primary winding and a second part of the primary winding; wherein, The first part of the primary winding, the secondary winding, the shielding layer, and the second part of the primary winding are arranged in sequence in a set direction; The first part of the primary winding is configured to be connected to the DC bus; the second part of the primary winding is configured to be connected to the main power device of the switching power supply; the first part of the primary winding is wound only one layer and is fully covered with a tight winding or a loose winding method; the second part of the primary winding is wound two layers with the same wire material as the first part of the primary winding and is fully covered with the whole layer; The shielding layer includes a shielding winding; the shielding winding is wound with any one of a metal foil, a metal strip, and a metal wire, wound one layer, and can be wound in a multi-strand parallel winding method; the shielding winding is configured to be connected to the positive pole of the DC bus, and the head and tail of the shielding winding are set to prevent short circuit; by taking power from the DC bus or the drain for the control circuit of the main power device, a high-frequency transformer without an auxiliary winding is set.

2. The transformer device according to claim 1, characterized in that It further includes: a transformer skeleton (1); The first part of the primary winding, the secondary winding, the shielding layer, and the second part of the primary winding are wound on the transformer skeleton (1); and an insulating layer is provided between adjacent parts of the first part of the primary winding, the secondary winding, the shielding layer, and the second part of the primary winding.

3. The transformer device according to claim 1 or 2, characterized in that The first end of the first part of the primary winding is configured to be connected to the positive pole of the DC bus; the second end of the first part of the primary winding is configured to be connected to the intermediate node of the transformer device.

4. The transformer device according to claim 1 or 2, characterized in that, The secondary winding can determine at least one of the number of winding strands, wire diameter, and number of turns according to at least one of the target output number of paths, target output current, and target output voltage.

5. The transformer device according to claim 1 or 2, characterized in that The first end of the second part of the primary winding is configured to be connected to the intermediate node of the transformer device; the second end of the second part of the primary winding is configured to be connected to the drain of the main power device of the switching power supply.

6. A switching power supply, characterized in that, Includes: A rectifier filter circuit, a high-frequency transformer, a main control unit, an AC low-impedance bypass circuit, a freewheeling and absorption circuit, and an output filter circuit; The main control unit includes: a main switch device and a control system; the high-frequency transformer adopts the transformer device described in any one of claims 1 to 5; wherein, The rectifier filter circuit is connected to the primary winding of the transformer device and the main control unit; the secondary winding of the transformer device is connected to the output filter circuit after passing through the freewheeling and absorption circuit; The control system takes power from the secondary side of the transformer device at the first output voltage; takes power from the primary side of the transformer device at the second output voltage; the output accuracy of the first output voltage is greater than the output accuracy of the second output voltage.

7. The switching power supply according to claim 6, characterized in that The rectifying and filtering circuit includes a rectifier bridge and a filtering circuit; the rectifier bridge is arranged in cooperation with the filtering circuit; the filtering circuit includes two differential-mode inductors and two capacitors; the two differential-mode inductors are arranged in parallel, and the two capacitors are arranged in parallel at the ends of the two differential-mode inductors.

8. The switching power supply according to claim 7, wherein The rectifier bridge is arranged between the two capacitors and on either side of the two differential-mode inductors, or the rectifier bridge is arranged on the same side of the two capacitors; among the two capacitors, the capacitor on the AC side is a film capacitor, and the capacitor on the DC side is an electrolytic capacitor.

9. A power adapter, characterized in that, It includes: The switching power supply according to any one of claims 6 to 8.

Images