Planar transformer, power converter and electronic equipment

Abstract

The utility model provides a planar transformer, a power converter and electronic equipment. The transformer comprises a first primary winding, a power supply winding, an auxiliary winding and a first shielding layer, the power supply winding is arranged on one side of the first sub-winding and is used for supplying power to an external power device; the auxiliary winding is arranged between the first sub-winding and the power supply winding and forms a mutual inductance structure with the first primary winding; the relative voltage difference between the auxiliary winding and the power supply winding is large, and the interference formed between the auxiliary winding and the power supply winding is large, so that the first shielding layer is arranged between the power supply winding and the auxiliary winding to suppress the common-mode interference between the power supply winding and the auxiliary winding; therefore, the common-mode interference of the planar transformer can be reduced to a greater extent; and on the other hand, the first shielding layer is grounded, so that the interference current can flow to the ground, and the common-mode interference in the planar transformer can be further reduced.

Description

Technical Field

[0001] The present application belongs to the field of electronic power technology, and in particular relates to a planar transformer, a power converter and an electronic device. Background Art

[0002] A planar transformer is a transformer with the characteristics of high frequency, low profile, small height and high operating frequency.

[0003] In the related art, the planar transformer includes a multi-layer structure, and capacitance and stray inductance are easily formed between two adjacent layers to generate interference; especially between the auxiliary winding layer and the power supply winding layer, since there is a very large voltage difference between the two, the interference generated is particularly significant.

[0004] Therefore, how to reduce the interference in the planar transformer is a problem that those skilled in the art need to solve at present. Utility Model Content

[0005] The purpose of the present application is to provide a planar transformer, a power converter and an electronic device, aiming to solve the problem of large interference in the planar transformer in the traditional technology.

[0006] A first aspect of an embodiment of the present application provides a planar transformer, the transformer comprising:

[0007] a first primary winding;

[0008] A power supply winding is arranged on one side of the first primary winding;

[0009] An auxiliary winding is arranged between the first primary winding and the power supply winding and forms a mutual inductance structure with the first primary winding;

[0010] The first shielding layer is arranged between the power supply winding and the auxiliary winding to suppress common mode interference between the power supply winding and the auxiliary winding; wherein the first shielding layer is grounded.

[0011] In some embodiments of the present application, the first shielding layer completely covers the power supply winding in a first direction, and the first direction is a direction from the auxiliary winding to the power supply winding;

[0012] And / or, the first shielding layer completely covers the auxiliary winding in a second direction, and the second direction is opposite to the first direction.

[0013] In some embodiments of the present application, the first shielding layer is a metal layer.

[0014] In some embodiments of the present application, the planar transformer further includes:

[0015] The secondary winding is arranged on a side of the power supply winding away from the first shielding layer;

[0016] A second primary winding is arranged on a side of the secondary winding away from the power supply winding, the second primary winding is connected in series with the first primary winding, and forms a mutual inductance structure with the secondary winding;

[0017] The second shielding layer is arranged between the secondary winding and the second primary winding to suppress common mode interference between the secondary winding and the second primary winding and between the power supply winding and the second primary winding.

[0018] The second shielding layer is a metal layer, and the second shielding layer is grounded.

[0019] In some embodiments of the present application, the first primary winding includes a first sub-winding and a second sub-winding connected in series, the first sub-winding is arranged on one side of the auxiliary winding, and the second sub-winding is arranged between the first sub-winding and the auxiliary winding;

[0020] And / or, the auxiliary winding includes a third sub-winding and a fourth sub-winding connected in series with each other, the third sub-winding is arranged on one side of the first primary winding, and the fourth sub-winding is arranged between the third sub-winding and the first shielding layer;

[0021] And / or, the second primary winding includes a fifth sub-winding and a sixth sub-winding connected in series, the fifth sub-winding is arranged on one side of the second shielding layer, and the sixth sub-winding is arranged on a side of the fifth sub-winding away from the second shielding layer.

[0022] In a second aspect, the present application also provides a power converter, comprising the above-mentioned planar transformer.

[0023] In some embodiments of the present application, the power converter further includes a first diode and a first capacitor, and the first diode and the first capacitor are connected in series at two ends of the power supply winding.

[0024] In some embodiments of the present application, the planar transformer includes a secondary winding; the power converter also includes a second diode and a second capacitor, the second diode and the second capacitor are connected in series at both ends of the secondary winding, and the secondary winding is grounded.

[0025] In some embodiments of the present application, the planar transformer includes a secondary winding, a second primary winding and a second shielding layer; the power converter also includes a third capacitor and a power switch tube, a first signal layer is provided on a side of the first primary winding away from the auxiliary winding, and a second signal layer is provided on a side of the second primary winding away from the second shielding layer;

[0026] One end of the third capacitor is connected to the first signal layer, and the other end of the third capacitor is used to connect to the second signal layer; the power switch tube is arranged between the third capacitor and the second signal layer to control the on and off between the third capacitor and the second signal layer.

[0027] In a third aspect, the present application also provides an electronic device, comprising the above-mentioned power converter.

[0028] Compared with the prior art, the beneficial effects of the embodiments of the utility model are as follows: the above-mentioned planar transformer, power converter and electronic device, the transformer includes a first primary winding, a power supply winding, an auxiliary winding and a first shielding layer; the power supply winding is arranged on one side of the first sub-winding, for supplying power to the first primary winding; the auxiliary winding is arranged between the first sub-winding and the power supply winding, and forms a mutual inductance structure with the first primary winding; since the relative voltage difference between the auxiliary winding and the power supply winding is large, the interference formed therebetween is also large, so in this application, the first shielding layer is arranged between the power supply winding and the auxiliary winding to suppress the common-mode interference between the power supply winding and the auxiliary winding, which is beneficial to further reduce the common-mode interference of the planar transformer; on the other hand, by setting the first shielding layer to be grounded, the interference current can flow to the ground, which is beneficial to further reduce the common-mode interference in the planar transformer. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic diagram of the structure of a planar transformer provided in one embodiment of the present application;

[0030] Figure 2 A schematic diagram of the circuit structure of a planar transformer provided in one embodiment of the present application;

[0031] Figure 3 A schematic diagram of the structure of a planar transformer provided in another embodiment of the present application.

[0032] Explanation of specific element symbols: 100-first primary winding, 110-first sub-winding, 120-second sub-winding, 200-auxiliary winding, 210-third sub-winding, 220-fourth sub-winding, 300-first shielding layer, 400-power supply winding, 500-secondary winding, 600-second shielding layer, 700-second primary winding, 710-fifth sub-winding, 720-sixth sub-winding, 800-first signal layer, 900-second signal layer, a-first direction, b-second direction, D1-first diode, D2-second diode, C1-first capacitor, C2-second capacitor, C3-third capacitor, Q1-power switch tube. DETAILED DESCRIPTION

[0033] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0034] It should be noted that when an element is referred to as being "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0035] It should be understood that the terms "length", "width", "up", "down", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0036] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0037] It should be noted that as the switching frequency of semiconductor devices increases significantly, their power density increases accordingly, and the electromagnetic interference (EMI) problem of power converters becomes more serious. The noise peaks reflected in actual tests move to higher frequency bands. Compared with ordinary wound transformers, current planar transformers have the characteristics of high frequency, low profile, small height and high operating frequency, which makes them have significant advantages in reducing equipment size and improving efficiency.

[0038] However, planar transformers usually have a multi-layer structure, with parasitic capacitance and stray inductance between layers. In addition, since the relative area between layers in a planar transformer is large, the dielectric constant of the material is also large, which leads to larger parasitic capacitance and stray inductance in the planar transformer. Parasitic capacitance and stray inductance will increase EMI problems, which will have a negative impact on the entire electronic device. Therefore, for planar transformers, the EMI problem is more serious.

[0039] Specifically, for planar transformers, when power semiconductors perform high-frequency rapid switching, large voltage change rates (du / dt) and current change rates (di / dt) will be generated, which will cause various coupling effects with parasitic capacitance and stray inductance in the line, resulting in serious common-mode interference.

[0040] In the related art, the planar transformer includes a primary winding, a secondary winding, an auxiliary winding and a power supply winding. The power supply winding supplies power to the external power device, and the primary winding and the secondary winding can form a mutual inductance structure to achieve voltage conversion. The auxiliary winding and the primary winding can also form a mutual inductance structure, and the multiple of the voltage conversion can be achieved by adjusting the auxiliary winding. There will be a large voltage difference between the auxiliary winding and the power supply winding, so there will be greater interference between the auxiliary winding and the power supply winding.

[0041] Based on this, the present application improves the related planar transformer, power converter and electronic equipment.

[0042] Please refer to Figure 1 and Figure 2 , Figure 1 FIG. 4 shows a schematic diagram of the structure of the planar transformer provided in this embodiment. Figure 2 The schematic diagram of the circuit structure of the planar transformer provided in this embodiment is shown. A planar transformer in this embodiment includes a first primary winding 100, a power supply winding 400, an auxiliary winding 200 and a first shielding layer 300; the power supply winding 400 is arranged on one side of the first primary winding 100, and is used to supply power to an external power device; the auxiliary winding 200 is arranged between the first primary winding 100 and the power supply winding 400, and forms a mutual inductance structure with the first primary winding 100; the first shielding layer 300 is arranged between the power supply winding 400 and the auxiliary winding 200 to suppress the common mode interference between the power supply winding 400 and the auxiliary winding 200; wherein the first shielding layer 300 is grounded.

[0043] It should be explained that the power supply winding 400 can supply power to external power devices, which may be MOS tubes, capacitors, inductors, etc. The auxiliary winding 200 is usually composed of a winding with a small number of turns. The auxiliary winding 200 is placed on one side of the secondary winding 500 to form a mutual inductance structure with the primary winding. The auxiliary winding 200 can be used to provide additional power and circuit control, and can also be used to increase the voltage and current capabilities of the winding. In addition, it can also improve the voltage regulation performance, improve the stability of the winding, and improve the short-circuit resistance of the transformer, reducing damage during short circuits.

[0044] In the current planar transformer, the relative voltage difference between the auxiliary winding 200 and the power supply winding 400 is large, and the interference formed therebetween is also greater. Therefore, in the present application, the first shielding layer 300 is set between the power supply winding 400 and the auxiliary winding 200 to suppress the common-mode interference between the power supply winding 400 and the auxiliary winding 200, thereby helping to reduce the common-mode interference of the planar transformer to a greater extent; on the other hand, the first shielding layer 300 is also set to be grounded so that the interference current can flow to the ground, which is conducive to further reducing the common-mode interference in the planar transformer.

[0045] In some embodiments of this application, please continue to refer to Figure 1 In this embodiment, the first shielding layer 300 completely covers the power supply winding 400 in the first direction a, and the first direction a is the direction in which the auxiliary winding 200 points to the power supply winding 400. In this way, it is beneficial to improve the shielding effect of the power supply winding 400, and further to reduce the interference of the auxiliary winding 200 on the power supply winding 400. It should be explained that the first shielding layer 300 completely covers the power supply winding 400 in the first direction a, which can be understood as the first shielding layer 300 covering the winding area of ​​the power supply winding 400 in the power supply winding 400 layer.

[0046] In another embodiment, the first shielding layer 300 completely covers the auxiliary winding 200 in the second direction b, and the second direction b is opposite to the first direction a. In this way, it is beneficial to improve the shielding effect of the auxiliary winding 200, and further to reduce the interference of the power supply winding 400 on the auxiliary winding 200. It should be explained that the first shielding layer 300 completely covers the auxiliary winding 200 in the second direction b, which can be understood as the first shielding layer 300 covering the winding area of ​​the auxiliary winding 200 in the auxiliary winding 200 layer.

[0047] In some embodiments of the present application, the first shielding layer 300 is a metal layer. This is because metal generally has a better electromagnetic shielding effect, and a polymer material layer with a high electromagnetic shielding effect can also be used. In some embodiments, the first shielding layer 300 is made of copper material.

[0048] In some embodiments of this application, please continue to refer to Figure 1The planar transformer of this embodiment also includes a secondary winding 500, a second primary winding 700 and a second shielding layer 600; the secondary winding 500 is arranged on the side of the power supply winding 400 away from the first shielding layer 300; the second primary winding 700 is arranged on the side of the secondary winding 500 away from the power supply winding 400, the second primary winding 700 is connected in series with the first primary winding 100, and forms a mutual inductance structure with the secondary winding 500; the second shielding layer 600 is arranged between the secondary winding 500 and the second primary winding 700 to suppress common mode interference between the secondary winding 500 and the second primary winding 700 and between the power supply winding 400 and the second primary winding 700.

[0049] It is understandable that there is also a large parasitic capacitance and stray inductance between the secondary winding 500 and the second primary winding 700; there is also a large parasitic capacitance and stray inductance between the power supply winding 400 and the second primary winding 700. Like the role of the first shielding layer 300 between the power supply winding 400 and the auxiliary winding 200, the second shielding layer 600 between the secondary winding 500 and the second primary winding 700 and between the power supply winding 400 and the second primary winding 700 can also play a role in suppressing common mode interference.

[0050] In some embodiments, the second shielding layer 600 of this embodiment is a metal layer. This is because metal generally has a better electromagnetic shielding effect, and a polymer material layer with a high electromagnetic shielding effect can also be used. In some embodiments, the first shielding layer 300 is made of copper material.

[0051] In some embodiments, the second shielding layer 600 is grounded. In this embodiment, by setting the second shielding layer 600 to be grounded, the interference current can flow to the ground, which is beneficial to further reduce the common mode interference in the planar transformer.

[0052] In some embodiments of this application, please refer to Figure 3 , Figure 3 The first primary winding 100 of the present embodiment includes a first sub-winding 110 and a second sub-winding 120 connected in series, the first sub-winding 110 is arranged on one side of the auxiliary winding 200, and the second sub-winding 120 is arranged between the first sub-winding 110 and the auxiliary winding 200.

[0053] In some embodiments, please refer to Figure 3 The auxiliary winding 200 includes a third sub-winding 210 and a fourth sub-winding 220 connected in series. The third sub-winding 210 is arranged on one side of the first primary winding 100 , and the fourth sub-winding 220 is arranged between the third sub-winding 210 and the first shielding layer 300 .

[0054] In some embodiments, please refer to Figure 3 The second primary winding 700 includes a fifth sub-winding 710 and a sixth sub-winding 720 connected in series. The fifth sub-winding 710 is arranged on one side of the second shielding layer 600 , and the sixth sub-winding 720 is arranged on a side of the fifth sub-winding 710 away from the second shielding layer 600 .

[0055] Furthermore, in order to better implement the planar transformer in any of the above embodiments, this embodiment further provides a power converter based on the above planar transformer, including the planar transformer in any of the above embodiments.

[0056] In some embodiments of this application, please continue to refer to Figure 2 The power converter of this embodiment further includes a first diode D1 and a first capacitor C1, and the first diode D1 and the first capacitor C1 are connected in series at both ends of the power supply winding 400. Specifically, the positive electrode of the first diode D1 is connected to the power supply winding 400, and the negative electrode is connected to the first capacitor C1. In some embodiments, the power supply winding 400 is grounded.

[0057] In some embodiments of this application, please continue to refer to Figure 2 and Figure 3 The power converter of this embodiment further includes a second diode D2 and a second capacitor C2, the second diode D2 and the second capacitor C2 are connected in series at both ends of the secondary winding 500, and the secondary winding 500 is grounded. Specifically, the positive electrode of the second diode D2 is connected to the secondary winding 500, and the negative electrode is connected to the second capacitor C2. In some embodiments, the secondary winding 500 is grounded.

[0058] In some embodiments of this application, please continue to refer to Figure 2 and Figure 3 The power converter of this embodiment includes a third capacitor C3 and a power switch tube Q1. A first signal layer 800 is provided on the side of the first primary winding 100 away from the auxiliary winding 200, and a second signal layer 900 is provided on the side of the second primary winding 700 away from the second shielding layer 600; one end of the third capacitor C3 is connected to the first signal layer 800, and the other end of the third capacitor C3 is used to connect to the second signal layer 900; the power switch tube Q1 is arranged between the third capacitor C3 and the second signal layer 900 to control the on-off between the third capacitor C3 and the second signal layer 900.

[0059] In some embodiments, the power switch tube Q1 is a MOS tube.

[0060] Furthermore, in order to better implement the power converter in any of the above embodiments, based on the above power converter, this embodiment also provides an electronic device including the above power converter.

[0061] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0062] The basic concepts have been described above. Obviously, for those skilled in the art, the above detailed disclosure is only for example and does not constitute a limitation of the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements and amendments to the present application. Such modifications, improvements and amendments are suggested in the present application, so such modifications, improvements and amendments still belong to the spirit and scope of the exemplary embodiments of the present application.

[0063] At the same time, the present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0064] Similarly, it should be noted that in order to simplify the description of the disclosure of this application and thus help understand one or more utility model embodiments, in the above description of the embodiments of this application, multiple features are sometimes combined into one embodiment, drawing or description thereof. However, this disclosure method does not mean that the features required by the object of this application are more than the features mentioned in the claims. In fact, the features of the embodiments are less than all the features of the single embodiment disclosed above.

[0065] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A planar transformer, characterized in that: The transformer includes: a first primary winding; A power supply winding, arranged on one side of the first primary winding; an auxiliary winding, arranged between the first primary winding and the power supply winding, and forming a mutual inductance structure with the first primary winding; A first shielding layer is arranged between the power supply winding and the auxiliary winding to suppress common mode interference between the power supply winding and the auxiliary winding; wherein the first shielding layer is grounded.

2. The planar transformer according to claim 1, characterized in that: The first shielding layer completely covers the power supply winding in a first direction, and the first direction is a direction in which the auxiliary winding points to the power supply winding; And / or, the first shielding layer completely covers the auxiliary winding in a second direction, and the second direction is opposite to the first direction.

3. The planar transformer according to claim 1 or 2, characterized in that: The first shielding layer is a metal layer.

4. The planar transformer according to claim 1, characterized in that: The planar transformer also includes: A secondary winding is arranged on a side of the power supply winding away from the first shielding layer; a second primary winding, arranged on a side of the secondary winding away from the power supply winding, the second primary winding being connected in series with the first primary winding and forming a mutual inductance structure with the secondary winding; a second shielding layer, the second shielding layer being arranged between the secondary winding and the second primary winding to suppress common mode interference between the secondary winding and the second primary winding and between the power supply winding and the second primary winding; Wherein, the second shielding layer is a metal layer, and the second shielding layer is grounded.

5. The planar transformer according to claim 4, characterized in that: The first primary winding includes a first sub-winding and a second sub-winding connected in series, the first sub-winding is arranged at one side of the auxiliary winding, and the second sub-winding is arranged between the first sub-winding and the auxiliary winding; And / or, the auxiliary winding includes a third sub-winding and a fourth sub-winding connected in series, the third sub-winding is arranged on one side of the first primary winding, and the fourth sub-winding is arranged between the third sub-winding and the first shielding layer; And / or, the second primary winding includes a fifth sub-winding and a sixth sub-winding connected in series, the fifth sub-winding is arranged on one side of the second shielding layer, and the sixth sub-winding is arranged on a side of the fifth sub-winding away from the second shielding layer.

6. A power converter, characterized in that: A planar transformer comprising any one of claims 1 to 5.

7. The power converter according to claim 6, characterized in that: The power converter further includes a first diode and a first capacitor, wherein the first diode and the first capacitor are connected in series at two ends of the power supply winding.

8. The power converter according to claim 6, characterized in that: The planar transformer includes a secondary winding; the power converter also includes a second diode and a second capacitor, the second diode and the second capacitor are connected in series at two ends of the secondary winding, and the secondary winding is grounded.

9. The power converter according to claim 6, wherein: The planar transformer includes a secondary winding, a second primary winding and a second shielding layer; the power converter also includes a third capacitor and a power switch tube, a first signal layer is provided on a side of the first primary winding away from the auxiliary winding, and a second signal layer is provided on a side of the second primary winding away from the second shielding layer; One end of the third capacitor is connected to the first signal layer, and the other end of the third capacitor is used to connect to the second signal layer; the power switch tube is arranged between the third capacitor and the second signal layer to control the on and off between the third capacitor and the second signal layer.

10. An electronic device, characterized in that: A power converter comprising any one of claims 6 to 9.

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