PCB transformer coil board and PCB transformer

Abstract

A PCB transformer coil board and a PCB transformer are provided. The PCB transformer coil board includes: a Q-layer PCB and P coupled coil groups. The coupled coil group is disposed on the PCB, and each coupled coil group includes two primary coils and one secondary coil disposed between the two primary coils. P is an integer greater than 0; when P is an even number, Q=3P, or when P is an odd number, Q=3P+1; and an inlet end and an outlet end of the secondary coil on at least one layer of the PCB are separately provided on an outer circumference of the secondary coil.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present disclosure claims priorities to Chinese Patent Application No. 202320234651.1, filed by BYD Company Limited on February 2, 2023, and entitled "PCB TRANSFORMER COIL BOARD AND PCB TRANSFORMER", to Chinese Patent Application No. 202320637479.4, filed by BYD Company Limited on March 27, 2023, and entitled "TRANSFORMER", and to Chinese Patent Application No. 202310349360.1, filed by BYD Company Limited on March 27, 2023, and entitled "TRANSFORMER", all of which are incorporated herein by reference in their entireties.TECHNICAL FIELD

[0002] This application relates to the field of transformer technologies, and in particular, to a PCB transformer coil board, and a PCB transformer including the PCB transformer coil board.BACKGROUND

[0003] PCB transformers are mainly used in switching power supplies. With development of high-frequency switching power supplies, a coupling effect of the PCB transformer has increasingly large impact on the switching power supply. In a conventional technology, a primary coil and a secondary coil are usually stacked in a staggered manner. This PCB transformer has poor performance, and cannot meet a high-frequency requirement of the switching power supply. In addition, it is prone to difficult routing because it is difficult for a tail end of the primary coil or the secondary coil to penetrate from an inner side of the coil.SUMMARY

[0004] This application is intended to resolve at least one of technical problems in a related technology to some extent.

[0005] Therefore, this application provides a PCB transformer coil board.

[0006] The PCB transformer coil board according to embodiments of this application includes an N-layer PCB and M coupled coil groups. The coupled coil group is disposed on the PCB, and each coupled coil group includes two primary coils and one secondary coil disposed between the two primary coils. M is an integer greater than 0; when M is an even number, N=3M, or when M is an odd number, N=3M+1; and an inlet end and an outlet end of the secondary coil on at least one layer of the PCB are separately provided on an outer circumference of the secondary coil.

[0007] In the PCB transformer coil board according to this application, the coupled coil group is formed by sandwiching one secondary coil between two primary coils, so that a coupling effect of the coupled coil group can be enhanced. In addition, a quantity of layers of the PCB is limited by adjusting a quantity of coupled coil groups, so that ends of the primary coil and the secondary coil are all located outside the coil, and difficult routing because the end of the coil is located inside the coil are avoided.

[0008] This application further provides a PCB transformer, including the foregoing PCB transformer coil board.

[0009] This application further provides a PCB transformer, including a coil. The coil includes a primary coil and a secondary coil, the coil extends from a starting end to a terminating end in a spiral direction from inside to outside. In the spiral direction from inside to outside, a width of the primary coil increases continuously, and a width of the secondary coil remains unchanged.

[0010] This application further provides a PCB transformer, including a primary coil and a secondary coil. The primary coil and the secondary coil are insulated from each other and magnetically coupled. The primary coil extends from a first starting end to a first terminating end in a spiral direction from inside to outside, and includes a plurality of head-to-tail winding segments. The primary coil has at least two line widths, and the secondary coil has one line width.

[0011] A part of additional aspects and advantages of this application is provided in part in the following descriptions, the part becomes clear from the following descriptions, or may be learned through the practice of this application.BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG. 1 is a diagram of a PCB transformer coil board according to Embodiment 1 of this application; FIG. 2 is an exploded view of a PCB transformer coil board according to Embodiment 1 of this application; FIG. 3 is a diagram of a first layer of a PCB transformer coil board according to Embodiment 1 of this application; FIG. 4 is a diagram of a second layer of a PCB transformer coil board according to Embodiment 1 of this application; FIG. 5 is a diagram of a third layer of a PCB transformer coil board according to Embodiment 1 of this application; FIG. 6 is a diagram of a fourth layer of a PCB transformer coil board according to Embodiment 1 of this application; FIG. 7 is a diagram of a fifth layer of a PCB transformer coil board according to Embodiment 1 of this application; FIG. 8 is a diagram of a sixth layer of a PCB transformer coil board according to Embodiment 1 of this application; FIG. 9 is a diagram of a PCB transformer coil board according to Embodiment 2 of this application; FIG. 10 is a diagram of a first layer of a PCB transformer coil board according to Embodiment 2 of this application; FIG. 11 is a diagram of a second layer of a PCB transformer coil board according to Embodiment 2 of this application; FIG. 12 is a diagram of a third layer of a PCB transformer coil board according to Embodiment 2 of this application; FIG. 13 is a diagram of a fourth layer of a PCB transformer coil board according to Embodiment 2 of this application; FIG. 14 is a diagram of a secondary coil of a PCB transformer coil board according to Embodiment 3 of this application; FIG. 15 is a diagram of a secondary coil of a PCB transformer coil board according to Embodiment 4 of this application; FIG. 16 is a diagram of a secondary coil of a PCB transformer coil board according to Embodiment 5 of this application; FIG. 17 is a curve graph of a change in an output voltage generated by a secondary coil in Embodiment 3 to Embodiment 5 according to an embodiment of this application; FIG. 18 is a diagram of winding of a printed circuit board-based coil, namely, PCB coil, with unequal line widths according to an embodiment of this application; FIG. 19 is a diagram of a transformer according to an embodiment of this application; FIG. 20(a) is a diagram of routing of a primary coil on a top layer according to an embodiment of this application; FIG. 20(b) is a diagram of routing of a secondary coil on a bottom layer according to an embodiment of this application; FIG. 20(c) is a diagram of multi-layer routing according to an embodiment of this application; FIG. 21 is a diagram of a transformer according to still another embodiment of this application; FIG. 22(a) is a diagram of routing of a primary coil on a top layer according to still another embodiment of this application; FIG. 22(b) is a diagram of routing of a primary coil on a second layer according to still another embodiment of this application; FIG. 22(c) is a diagram of routing of a primary coil on a fourth layer according to still another embodiment of this application; FIG. 22(d) is a diagram of routing of a secondary coil on a third layer according to still another embodiment of this application; FIG. 22(e) is a diagram of routing on another layer according to still another embodiment of this application; FIG. 23 is a diagram of a transformer according to another embodiment of this application; FIG. 24(a) is a diagram of routing of a primary coil on a top layer according to another embodiment of this application; FIG. 24(b) is a diagram of routing of a primary coil on a second layer according to another embodiment of this application; FIG. 24(d) is a diagram of routing of a secondary coil on a third layer according to another embodiment of this application; FIG. 24(b) is a diagram of routing of a secondary coil on a bottom layer according to another embodiment of this application; FIG. 25(a) is a diagram of a primary coil according to yet another embodiment of this application; FIG. 25(b) is a diagram of a structure of a primary coil in a conventional technology; FIG. 26 is a diagram of comparison of output voltages of transformers including primary coils in FIG. 25(a) and FIG. 25(b); FIG. 27 is a waveform diagram of output voltages of transformers formed by different combinations; FIG. 28 is a diagram of a primary coil and a secondary coil of a transformer according to an embodiment of this application; FIG. 29 is a diagram of an unfolded primary coil of a transformer according to an embodiment of this application; FIG. 30 is a diagram of an unfolded primary coil of a transformer according to an embodiment of this application; FIG. 31 is a diagram of comparison of waveforms of output voltages of the transformer having the primary coil shown in FIG. 30 and a transformer having a primary coil of another structure; FIG. 32 is a diagram of an unfolded primary coil of a transformer according to an embodiment of this application; FIG. 33 is a diagram of an unfolded primary coil of a transformer according to an embodiment of this application; FIG. 34 is a diagram of an unfolded winding segment of a primary coil of a transformer according to an embodiment of this application; FIG. 35 is a diagram of a primary coil of a transformer according to an embodiment of this application; FIG. 36 is a diagram of a primary coil of a transformer according to an embodiment of this application; FIG. 37 is a diagram of a primary coil of a transformer according to an embodiment of this application; FIG. 38 is a diagram of comparison of waveforms of output voltages of the transformer having the primary coil shown in FIG. 37 and a transformer having a primary coil of another structure; FIG. 39 is a diagram of a transformer according to an embodiment of this application; FIG. 40 is a diagram of a line drawn on each layer of the board of a transformer in FIG. 12; FIG. 41 is a diagram of a transformer according to an embodiment of this application; FIG. 42 is a diagram of a line drawn on each layer of a board of the transformer in FIG. 41; FIG. 43 is a diagram of a transformer according to an embodiment of this application; and FIG. 44 is a diagram of a line drawn on each layer of a board of the transformer in FIG. 43. DESCRIPTION OF EMBODIMENTS

[0013] The following describes in detail embodiments of this application, and examples of embodiments are shown in accompanying drawings, where same or similar reference numerals throughout represent same or similar elements or elements having same or similar functions. Embodiments described below with reference to the accompanying drawings are examples, are intended to explain this application, and shall not be understood as a limitation on this application.

[0014] First, it should be noted that this application is provided based on the foregoing priority documents. Therefore, terms in the priority documents are unified.

[0015] The reference numeral of "coil portion 10" in the priority document "202320637479.4" is changed to "coil portion 40".

[0016] The reference number "transformer 10" in the priority document "202310349360.1" is changed to "transformer 1000".

[0017] The "primary coil 20" in the priority document "202320637479.4", the "primary coil 10" in the priority document "202320234651.1", and the "primary coil 11" in the priority document "202310349360.1" are a same part and component, and are collectively named as a "primary coil 10".

[0018] The "secondary coil 30" in the priority document "202320637479.4", the "secondary coil 20" in the priority document "202320234651.1", and the "secondary coil 12" in the priority document "202310349360.1" are a same part and component, and are collectively named as a "secondary coil 20".

[0019] The "first connection end H1" in the priority document "202320637479.4", the "primary output end H1" in the priority document "202320234651.1", and the "first connection end H1" in the priority document "202310349360.1" are a same part and component, and are collectively named as a "primary output end H1".

[0020] The "second connection end H2" in the priority document "202320637479.4", the "primary input end H2" in the priority document "202320234651.1", and the "second connection end H2" in the priority document "202310349360.1" are a same part and component, and are collectively named as a "primary input end H2".

[0021] The "third connection end H3" in the priority document "202320637479.4", the "secondary input end H3" in the priority document "202320234651.1", and the "third connection end H3" in the priority document "202310349360.1" are a same part and component, and are collectively named as a "secondary input end H3".

[0022] The "fourth connection end H4" in the priority document "202320637479.4", the "secondary output end H4" in the priority document "202320234651.1", and the "fourth connection end H4" in the priority document "202310349360.1" are a same part and component, and are collectively named as a "secondary output end H4".

[0023] Therefore, names and reference numerals of same components in the two priority documents are unified.

[0024] The following first specifically describes in detail a PCB transformer coil board 100 according to an embodiment of this application with reference to the accompanying drawings.

[0025] As shown in FIG. 1 to FIG. 14, the PCB transformer coil board 100 according to this embodiment of this application includes a Q-layer PCB and P coupled coil groups.

[0026] The coupled coil group is disposed on the PCB, and each coupled coil group includes two primary coils 10 and one secondary coil 20 disposed between the two primary coils 10. P is an integer greater than 0; when P is an even number, Q=3P, or when P is an odd number, Q=3P+1; and an inlet end and an outlet end of the secondary coil 20 on at least one layer of the PCB are separately provided on an outer circumference of the secondary coil 20.

[0027] In other words, the PCB transformer coil board 100 according to this application embodiment mainly includes the Q PCBs and the P coupled coil groups. P may be an integer greater than 0, for example, 1, 2, 3, ..., or P, and at least one coupled coil group is provided on the PCB.

[0028] Each coupled coil group may correspond to a three-layer PCB. The two primary coils 10 in each coupled coil group may be disposed on a lower layer and an upper layer of the three-layer PCB, and the two primary coils 10 are connected in series. The secondary coil 20 in each coupled coil group may be disposed on an intermediate layer of the three-layer PCB. When the PCB transformer coil board 100 includes two or more coupled coil groups, primary coils 10 in the coupled coil groups may be sequentially connected in series to form a whole, and secondary coils 20 in the coupled coil groups may also be sequentially connected in series to form a whole. After being energized, the primary coil 10 may be coupled to the secondary coil 20, so that an induced current is formed in the secondary coil 20.

[0029] In addition, when P is an even number, the PCB transformer coil board 100 may include a 3P-layer PCB. For example, when P is 2, 4, or 6, there may be 6 layers, 12 layers, or 18 layers of the PCB respectively.

[0030] In this case, there are a total of 2P primary coils 10, and a total quantity of the primary coils 10 is an even number. This helps wind the primary coils 10 in a manner of winding one primary coil 10 inwardly and one primary coil 10 outwardly, so that two ends of a primary coil 10 formed by connecting the primary coils 10 in series are both located outside a coil, to facilitate a connection of the two ends of the primary coil 10 to external wiring terminals. Therefore, a quantity of primary coils 10 are set to be an even number, so that a quantity of connection parts present when the primary coils 10 are connected across layers can be effectively reduced.

[0031] There are a total of P secondary coils 20, and a total quantity of the secondary coils 20 is also an even number. Therefore, the secondary coils 20 may also be wound in a manner of winding one secondary coil 20 inwardly and one secondary coil 20 outwardly, so that two ends of a secondary coil 20 formed by connecting the secondary coils 20 in series are both located outside the coil, to facilitate connections of the two ends of the secondary coil 20 to external wiring terminals. Therefore, a quantity of secondary coils 20 are set to be an even number, so that a quantity of connection parts present when the secondary coils 20 are connected across layers can be effectively reduced.

[0032] When P is an odd number, the PCB transformer coil board 100 may include a 3P+1-layer PCB. For example, when P is 1, 3, or 5, there may be 4 layers, 10 layers, or 16 layers of the PCB respectively.

[0033] In this case, a total quantity of primary coils 10 may be 2P, so that a quantity of connection parts present when the primary coils 10 are connected across layers can be effectively reduced. A total quantity of secondary coils 20 may be P+1. At least one secondary coil 20 may be directly connected to a corresponding external terminal on the PCB. For example, in P+1 secondary coils 20, P secondary coils 20 may be sequentially wound in a manner of winding one secondary coil 20 inwardly and one secondary coil 20 outwardly. Because P is an odd number, one of two ends of a whole formed through winding of the P secondary coils 20 is inside the coil, and the other of the two ends is outside the coil. The end inside the coil may penetrate through a (P+1) th< layer of the PCB from the inside of coil to directly connect to the external wiring terminal without further winding. This avoids difficult routing because the end of the secondary coil 20 is located inside the coil.

[0034] Therefore, in the PCB transformer coil board 100 according to an embodiment of this application, a coupled coil group is formed by sandwiching one secondary coil 20 between two primary coils 10, so that the secondary coil 20 can be couple to the two primary coils 10, to enhance a coupling effect of the coupled coil group. In addition, a quantity of layers of the PCB is limited by adjusting a quantity of coupled coil groups, so that a quantity of coupled coil groups adapted by a multi-layer PCB can be determined. Therefore, ends of the primary coil 10 and the secondary coil 20 are all located outside the coil, and difficult routing because the end of the coil is located inside the coil are avoided.

[0035] According to an embodiment of this application, a line width of the primary coil 10 is greater than a line width of the secondary coil 20. It should be noted that coil layers formed through winding of each primary coil 10 and secondary coil 20 have approximately same inner diameters and approximately same outer diameters. A larger quantity of turns of the secondary coil 20 wrapped under one turn of primary coil 10 indicates a better coupling effect of the coupled coil group. Therefore, the line width of the primary coil 10 is set to be greater than that of the secondary coil 20, to help improve the coupling effect of the coupled coil group and increase an induced voltage generated by the secondary coil 20, so that a coupling effect of the PCB transformer coil board 100 is improved.

[0036] According to some other embodiments of this application, a quantity of turns of the secondary coil 20 in each coupled coil group is greater than a quantity of turns of the corresponding primary coil 10. Because each primary coil 10 and secondary coil 20 has approximately same inner diameters and approximately same outer diameters, the quantity of turns of the secondary coil 20 in each coupled coil group helps reduce the line width of the secondary coil 20, so that the quantity of turns of the secondary coil 20 wrapped under one turn of primary coil 10 is increased. This helps improve the coupling effect of the coupled coil group and increase the induced voltage generated by the secondary coil 20, so that the coupling effect of the PCB transformer coil board 100 is improved.

[0037] In some implementations of this application, in each coupled coil group, an inlet end of one primary coil 10 is provided within an inner circumference, an outlet end of the primary coil 10 is provided on an outer circumference, an inlet end of the other primary coil 10 is provided on the outer circumference, and an outlet end of the other primary coil 10 is provided within the inner circumference. The outlet end of the primary coil 10 is connected in series to the inlet end of the other primary coil 10 through a first via on an inner side of the primary coil 10.

[0038] In each coupled coil group, an upper layer and a lower layer may be primary coils 10, and an intermediate layer may be a secondary coil 20. The primary coil 10 on the upper layer may be wound from outside to inside, so that an inlet end of the primary coil 10 on the upper layer is located on an outer circumference of the coil, and an outlet end is located within an inner circumference of the coil. The primary coil 10 on the lower layer may be wound from inside to outside, so that an inlet end of the primary coil 10 on the lower layer is located within an inner circumference of the coil, and an outlet end is located on an outer circumference of the coil.

[0039] In addition, the outlet end of the primary coil 10 on the upper layer and the inlet end of the primary coil 10 on the lower layer may be connected in series through the first via. The first via may be provided on an inner circumferential side of the primary coil 10, so that the primary coils 10 on the upper layer and the lower layer can be directly connected through the PCB.

[0040] In this embodiment, winding directions of the two primary coils 10 in each coupled coil group may be opposite, and the two primary coils 10 are connected through the first via on the inner circumferential side of the coil, so that ends of a whole formed by connecting the two primary coils 10 in series may be located outside the coil, to facilitate a connection of the end of the primary coil 10 to a primary coil 10 in an adjacent coupled coil group or to an external wiring terminal.

[0041] According to some embodiments of this application, in two adjacent coupled coil groups, two adjacent primary coils 10 are connected in series through a second via on an outer side of the primary coil 10, an inlet end of a secondary coil 20 in one coupled coil group is provided on an outer circumference, an inlet end of a secondary coil 20 in the other coupled coil group is provided within an inner circumference, and two adjacent secondary coils 20 are connected in series through a third via.

[0042] For ease of description, the two adjacent coupled coil groups may be defined as a first coil group and a second coil group, the first coil group may be disposed on a lower side of the second coil group, a primary coil 10 on an upper layer of the first coil group is adjacent to a primary coil 10 on a lower layer of the second coil group. The primary coil 10 on the upper layer of the first coil group may be wound from inside to outside, and the primary coil 10 on the lower layer of the second coil group may be wound from outside to inside, an outlet end of the primary coil 10 on the upper layer of the first coil group and an inlet end of the primary coil 10 on the lower layer of the second coil group are both located on an outer circumferential side of the coil, the PCB may be provided with a second via, and the second via is located on the outer circumferential side of the coil. The outlet end of the primary coil 10 on the upper layer of the first coil group and the inlet end of the primary coil 10 on the lower layer of the second coil group may be connected through the second via, so that primary coils 10 are sequentially wound on respective layers of the PCB.

[0043] A secondary coil 20 in the first coil group and a secondary coil 20 in the second coil group are spaced apart, and the secondary coils 20 are spaced apart by the two primary coils 10. The secondary coil 20 in the first coil group may be wound from outside to inside, and the secondary coil 20 in the second coil group may be wound from inside to outside, so that an outlet end of the secondary coil 20 in the first coil group and an inlet end of the secondary coil 20 in the second coil group are both located on an inner circumferential side of the coil. The PCB may be provided with a third via, and the outlet end of the secondary coil 20 in the first coil group and the inlet end of the secondary coil 20 in the second coil group may be connected through the third via, so that secondary coils 20 are sequentially wound on respective layers of the PCB.

[0044] It should be noted that the third via may be provided on the inner circumferential side of the coil or the outer circumferential side of the coil, and a position of the third via may be determined based on positions of inlet ends and outlet ends of the two connected secondary coils 20. For example, when there are four coupled coil groups, a third via for a secondary coil 20 in a first coupled coil group and a secondary coil 20 in a second coupled coil group to connect in series may be provided on an inner circumferential side of the coil, a third via for the secondary coil 20 in the second coupled coil group and a secondary coil 20 in a third coupled coil group to connect in series may be provided on an outer circumferential side of the coil, and a third via for the secondary coil 20 in the third coupled coil group and a secondary coil 20 in a fourth coupled coil group may be provided on the inner circumferential side of the coil.

[0045] In this embodiment, the two adjacent primary coils 10 in the two adjacent coupled coil groups are connected in series through the second via outside the coil, so that the primary coils 10 are sequentially wound on the PCB in a stacking order. Therefore, cross-interference between both an inlet end and an outlet end of each primary coil 10 and the coil. The secondary coils 20 in the two adjacent coupled coil groups may be connected in series through the third via, so that the secondary coils 20 are also sequentially wound on the PCB in a stacking order. Therefore, cross-interference between both an inlet end and an outlet end of each secondary coil 20 and the coil.

[0046] According to some other embodiments of this application, the first via, the second via, and the third via are spaced apart on the PCB.

[0047] It should be noted that the first via, the second via, and the third via each may penetrate and communicate each layer of the PCB, to simplify a production process of the PCB. The first via, the second via, and the third via are spaced apart on the PCB, so that a short circuit between primary coils 10 or secondary coils 20 connected through vias can be avoided.

[0048] There may be P first vias, there may be P-1 second vias, the P first vias are spaced apart and distributed on the inner circumferential side of the coil, and the P-1 second vias are spaced apart and distributed on the outer circumferential side of the coil. There may be a plurality of third vias, a part of the third vias may be spaced apart and distributed on the inner circumferential side of the coil, the other part of the third vias may be spaced apart and distributed on the outer circumferential side of the coil, and a quantity of the third vias may be determined based on a quantity of secondary coils 20.

[0049] In some implementations of this application, the PCB is provided with a primary input end H2, a primary output end H1, a secondary input end H3, and a secondary output end H4, the primary coil 10 is connected to the primary input end H2 and the primary output end H1, and the secondary coil 20 is connected to the secondary input end H3 and the secondary output end H4.

[0050] There may be four external wiring terminals, including the primary input end H2, the primary output end H1, the secondary input end H3, and the secondary output end H4, and the four external wiring terminals may be disposed on the PCB. The primary input end H2 and the primary output end H1 are configured to connect to the two ends of the primary coil 10, and the secondary input end H3 and the secondary output end H4 are configured to connect to the two ends of the secondary coil 20.

[0051] The primary input end H2 and the primary output end H1 may be spaced apart on one side of the coil, and the secondary input end H3 and the secondary output end H4 may be spaced apart on another side of the coil, to facilitate connections of the ends of the primary coil 10 or the secondary coil 20.

[0052] According to some embodiments of this application, the PCB includes a first layer, a second layer, a third layer, and a fourth layer. The primary coil 10 includes a first coil disposed on the first layer and a second coil disposed on the third layer, and the secondary coil 20 includes a third coil disposed on the second layer and a connection cable disposed on the fourth layer.

[0053] An inlet end of the first coil is connected to the primary input end H2, an outlet end of the first coil is connected to an inlet end of the second coil through a first via, an outlet end of the second coil is connected to the primary output end H1, an inlet end of the third coil is connected to the secondary input end H3, an outlet end of the third coil is connected to an inlet end of the connection cable, and an outlet end of the connection cable is connected to the secondary output end H4.

[0054] In other words, Q=4, and the PCB transformer coil board 100 in this embodiment includes the four-layer PCB. As shown in FIG. 9 to FIG. 14, the four layers of the PCB are sequentially stacked, the first layer and the third layer are configured to dispose the primary coil 10, and the second layer and the fourth layer are configured to dispose the secondary coil 20. The coils of the first layer to the third layer are combined to form a coupled coil group. That is, when Q=4, one coupled coil group may be disposed.

[0055] As shown in FIG. 10, on the first layer of the PCB, the first coil is wound from outside to inside, the inlet end of the first coil is formed as one end of the primary coil 10, and is connected to the primary input end H2, and the outlet end of the first coil is located on an inner circumferential side of the coil, and is connected to the inlet end of the second coil shown in FIG. 12 through the first via on the inner circumferential side of the coil. The second coil is wound from inside to outside, and the outlet end of the second coil is formed as the other end of the primary coil 10, and is connected to the primary output end H1.

[0056] As shown in FIG. 11, on the second layer of the PCB, the third coil is wound from inside to outside, the outlet end of the third coil is formed as one end of the secondary coil 20, and is connected to the secondary output end H4, and the inlet end of the third coil is located on the inner circumferential side of the coil, and is connected to the outlet end of the connection cable shown in FIG. 13 through a third via on the inner circumferential side of the coil. The inlet end of the connection cable is formed as the other end of the secondary coil 20, and is connected to the secondary input end H3.

[0057] In this embodiment, when there are four layers of the PCB, the PCB transformer coil board 100 may include a coil group, where primary coils 10 may be wound in a manner of winding one primary coil 10 inwardly and one primary coil 10 outwardly, so that two ends of the primary coil 10 are both located on an outer circumferential side of the coil, to facilitate connections to the primary input end H2 and the primary output end H1. The secondary coil 20 may be wound inward on one layer, and then directly penetrates from the inner circumferential side of the coil on the other layer and is connected to the secondary output end H4. The connection cable is disposed on the fourth layer of the PCB, so that a connection of the end of the secondary coil 20 can be facilitated. In addition, this also helps increase a quantity of turns of the primary coil 10 on the second layer. Therefore, a line width of the primary coil 10 is reduced, and the coupling effect of the PCB transformer coil board 100 is enhanced.

[0058] According to some other embodiments of this application, the PCB includes a first layer, a second layer, a third layer, a fourth layer, a fifth layer, and a sixth layer. The primary coil 10 includes a first coil, a second coil, a third coil, and a fourth coil that are sequentially disposed on the first layer, the third layer, the fourth layer, and the sixth layer, the secondary coil 20 includes a fifth coil and a sixth coil that are sequentially disposed on the second layer and the fifth layer, and there are two first vias.

[0059] An inlet end of the first coil is connected to the primary input end H2, an outlet end of the first coil is connected to an inlet end of the second coil through one first via, an outlet end of the second coil is connected to an inlet end of the third coil through a second via, an outlet end of the third coil is connected to an inlet end of the fourth coil through the other first via, an outlet end of the fourth coil is connected to the primary output end H1, an inlet end of the fifth coil is connected to the secondary input end H3, an outlet end of the fifth coil is connected to an inlet end of the sixth coil through a third via, and an outlet end of the sixth coil is connected to the secondary output end H4.

[0060] In other words, Q=6, and the PCB transformer coil board 100 in this embodiment includes the six-layer PCB. As shown in FIG. 1 to FIG. 8, the six layers of the PCB are sequentially stacked, the first layer, the third layer, the fourth layer, and the sixth layer are configured to dispose the primary coil 10, and the second layer and the fourth layer are configured to dispose the secondary coil 20. The coils of the first layer to the third layer are combined to form a coupled coil group, and the coils of the fourth layer to the sixth layer are combined to form another coupled coil group. That is, when Q=6, two coupled coil groups may be disposed to improve the coupling effect.

[0061] As shown in FIG. 3, on the first layer of the PCB, the first coil is wound from outside to inside, the inlet end of the first coil is formed as one end of the primary coil 10, and is connected to the primary input end H2, and the outlet end of the first coil is located on an inner circumferential side of the coil, and is connected to the inlet end of the second coil shown in FIG. 5 through the first via on the inner circumferential side of the coil. The second coil is wound from inside to outside, and the outlet end of the second coil is connected to the inlet end of the third coil shown in FIG. 6 through the second via on an outer circumferential side of the coil. The third coil is wound from outside to inside, and the outlet end of the third coil is connected to the inlet end of the fourth coil shown in FIG. 8 through the other first via on the inner circumferential side of the coil. The fourth coil is wound from inside to outside, and the outlet end of the fourth coil is formed as the other end of the primary coil 10, and is connected to the primary output end H1.

[0062] As shown in FIG. 4, on the second layer of the PCB, the fifth coil is wound from outside to inside, the outlet end of the fifth coil is formed as one end of the secondary coil 20, and is connected to the secondary output end H4, and the inlet end of the fifth coil is located on the inner circumferential side of the coil, and is connected to the outlet end of the sixth coil shown in FIG. 7 through the third via on the inner circumferential side of the coil. The sixth coil is wound from outside to inside, and the inlet end of the sixth coil is formed as the other end of the secondary coil 20, and is connected to the secondary output end H4.

[0063] In this embodiment, when there are six layers of the PCB, the PCB transformer coil board 100 may include two coil groups to improve an effect of the PCB transformer coil board 100. Primary coils 10 may be sequentially wound from outside to inside and from inside to outside, so that two ends of the primary coil 10 are both located on the outer circumferential side of the coil, to facilitate connections to the primary input end H2 and the primary output end H1. Secondary coils 20 may be wound in a manner of winding one secondary coil 20 inwardly and one secondary coil 20 outwardly, so that two ends of the secondary coil 20 are both located on the outer circumferential side of the coil, to facilitate connections to an input end of the secondary coil 20 and an output end of the secondary coil 20.

[0064] The following describes in detail the PCB transformer coil board 100 in a plurality of embodiments of this application with reference to specific implementations.Embodiment 1

[0065] In this embodiment, as shown in FIG. 1 to FIG. 8, a primary coil 10 and a secondary coil 20 have a same center, the PCB is a 6-layer board, and N layers of the board are sequentially numbered 1 to 6 from a top layer to a bottom layer. That a quantity of coupled coil groups is 2 may be obtained according to a formula. Primary coils 10 in a first group of coupled coils are respectively located on a first layer and a third layer, and a secondary coil 20 is located on a second layer. Primary coils 10 in a second group of coupled coils are respectively located on a fourth layer and a sixth layer, and a secondary coil 20 is located on a fifth layer. The PCB is also provided with a primary output end H1, a primary input end H2, a secondary input end H3, and a secondary output end H4.

[0066] A through hole 1 is an intra-group through hole of the primary coils 10 in the first group of coupled coils, a through hole 3 is an intra-group through hole of the primary coils 10 in the second group of coupled coils, a through hole 2 is an inter-group through hole between the primary coils 10 in the first group of coupled coils and the primary coils 10 in the second group of coupled coils, and a through hole 4 is an inter-group through hole between the secondary coil 20 in the first group of coupled coils and the secondary coil 20 in the second group of coupled coils. The through hole 1 and the through hole 3 are formed as a first via, the through hole 2 is formed as a second via, and the through hole 4 is formed as a third via.

[0067] Primary coils 10 located on the first layer and the fourth layer are wound clockwise from outside to inside, and primary coils 10 located on the third layer and the sixth layer are wound clockwise from inside to outside. A secondary winding located in the first group of coupled coils is an odd group, and therefore, the secondary coil 20 located on the second layer is wound clockwise from inside to outside. A secondary winding located in the second group of coupled coils is an even group, and therefore, the secondary coil 20 located on the fourth layer is wound clockwise from outside to inside. Each primary coil 10 has 7 turns, each secondary coil 20 has 15 turns, there are a total of 28 turns of primary coils 10, and there are a total of 30 turns of secondary coils 20.Embodiment 2

[0068] In this embodiment, as shown in FIG. 9 to FIG. 13, a primary coil 10 and a secondary coil 20 have a same center, the PCB is a 4-layer board, and N layers of the board are sequentially numbered 1 to 4 from a top layer to a bottom layer. That a quantity of coupled coil groups is 1 may be obtained according to a formula. Primary coils 10 in the coupled coil group are respectively located on a first layer and a third layer, and a secondary coil 20 is located on a second layer. The PCB is also provided with a primary output end H1, a primary input end H2, a secondary input end H3, and a secondary output end H4.

[0069] A through hole 1 is an intra-group through hole of the primary coils 10 in the first group of coupled coils, and a through hole 5 is a routing through hole for the secondary coil 20 in the first group of coupled coils to penetrate from an inner side of the coil. The through hole 1 is formed as a first via, and the through hole 5 is formed as a third via.

[0070] The primary coil 10 located on the first layer is wound clockwise from outside to inside, and the primary coil 10 located on the third layer is wound clockwise from inside to outside. A secondary winding located in the coupled coil group is an odd group, and therefore, the secondary coil 20 located on the second layer is wound clockwise from inside to outside. The secondary coil 20 on the fourth layer penetrates through the through hole 5 in the coil and is directly connected to the secondary output end H4. Each primary coil 10 has 7 turns, each secondary coil 20 has 15 turns, there are a total of 14 turns of primary coils 10, and there are a total of 15 turns of secondary coils 20.Embodiment 3

[0071] Based on Embodiment 2, an area of the secondary coil 20 remains unchanged, a quantity of turns of the secondary coil 20 is changed, and the quantity of turns of the secondary coil 20 is set to 3 turns as shown in FIG. 14.Embodiment 4

[0072] Based on Embodiment 2, an area of the secondary coil 20 remains unchanged, a quantity of turns of the secondary coil 20 is changed, and the quantity of turns of the secondary coil 20 is set to 5 turns as shown in FIG. 15.Embodiment 5

[0073] Based on Embodiment 2, an area of the secondary coil 20 remains unchanged, a quantity of turns of the secondary coil 20 is changed, and the quantity of turns of the secondary coil 20 is set to 10 turns as shown in FIG. 16.

[0074] According to the law of electromagnetic induction, each turn of a secondary coil generates an induced voltage due to sensing of a change of a magnetic field. When a current in one turn of a primary coil 10 changes, a secondary coil 20 covered by the turn of the coil generates an induced voltage accordingly. A larger quantity of turns of the secondary coil covered by the turn of the primary coil 10 indicates a higher induced voltage that may be generated by the secondary coil 20 covered by the turn of the primary coil.

[0075] Embodiments 3 to 5 are simulated. In a case of a same quantity of turns of the primary coil and different quantities of turns of the secondary coil, a change of an output voltage generated by the secondary coil 20 with time is shown in FIG. 17. Embodiment 3 is indicated by a curve L1 in the figure, Embodiment 4 is indicated by a curve L2 in the figure, and Embodiment 5 is indicated by a curve L3 in the figure.

[0076] When the secondary coil 20 has 10 turns, an output voltage is approximately 19 V, and is far greater than output voltages in cases in which the secondary coil 20 has 3 turns and the secondary coil 20 has 5 turns. It can be clearly learned that a larger quantity of turns of the secondary coil 20 covered by one turn of the primary coil 10 indicates a higher induced voltage and a better coupling effect of a coupled coil group.Embodiment 6

[0077] Based on Embodiment 2, a quantity of turns of the secondary coil 20 is changed. Each primary coil 10 has 5 turns, each secondary coil 20 has 10 turns, there are a total of 10 turns of primary coils 10, and there are a total of 10 turns of secondary coils 20.Comparative embodiment

[0078] Based on Embodiment 6, a structure of the fourth layer and a quantity of turns of the secondary coil 20 on the second layer are changed. Five turns of a secondary coil 20 are disposed on the fourth layer, the quantity of turns of the secondary coil 20 on the second layer is set to 5 turns, there are a total of 10 turns of primary coils 10, and there are a total of 10 turns of secondary coils 20.

[0079] It should be noted that, energy generated by a primary coil 10 after a current flows into the primary coil 10 is fixed. Therefore, it is assumed that energy generated by each primary coil 10 is 1, and in a coupled coil group, a single secondary coil 20 may absorb energy, which is 1, generated by a primary coil 10 on a first layer, and also absorb energy, which is 1, generated by a primary coil 10 on a third layer. In this case, total energy absorbed by the secondary coil 20 in the coupled coil group is approximately 2.

[0080] In the comparative embodiment, the secondary coil 20 on the second layer may completely absorb the energy generated the primary coil 10 on the first layer, and the energy generated on the third layer is absorbed by the secondary coils 20 on the second layer and the fourth layer together. In this case, total energy absorbed by the secondary coils 20 is also approximately 2. Therefore, in a no-load case, output voltages in Embodiment 6 and the comparative embodiment are approximately the same, and test results are shown in Table 1. Table 1: Actual test resultsInput voltageFrequencyDuty cyclePower of a power supplyOutput voltageEmbodiment 6Turn ratio: 10:105 V1 MHz0.52.7 W18.769 VPrimary coils on a first layer and a third layer that are connected in series, and a secondary coil on a second layerComparative embodimentTurn ratio: 10:105 V1 MHz0.52.7 W18.678 VPrimary coils on a first layer and a third layer that are connected in series, and secondary coils on a second layer and a fourth layer that are connected in series

[0081] It may be clearly learned from Table 1 that the output voltages in Embodiment 6 and the comparative embodiment are approximately the same. Therefore, a voltage output by the coupled coil group provided in this application can be approximately the same as that in the conventional technology. However, a quantity of secondary coils 20 is less than a quantity of secondary coils 20 in the comparative embodiment. This helps simplify a structure of the PCB transformer coil board 100.

[0082] An embodiment of this application further provides a PCB transformer. The PCB transformer includes the PCB transformer coil board 100 according to any one of the foregoing embodiments. The PCB transformer may further include a magnetic core. The magnetic core may pass through the PCB. Each primary coil 10 and secondary coil 20 surrounds the magnetic core, so that the secondary coil 20 can cooperate with the primary coil 10 to form an induced current. Because the PCB transformer coil board 100 according to embodiments of this application has the foregoing technical effect, the PCB transformer according to this embodiment of this application also has the corresponding technical effect, to be specific, enhancing the coupling effect of the coupled coil group, to facilitate routing of the primary coil 10 and the secondary coil 20 from the outside of the coil.

[0083] The following specifically describes in detail the transformer according to this embodiment of this application with reference to the accompanying drawings.

[0084] As shown in FIG. 18 and FIG. 25(a), the transformer according to this embodiment of this application includes a coil, the coil includes a primary coil 10 and a secondary coil 20, and the coil extends from a starting end to a terminating end in a spiral direction from inside to outside. In the spiral direction from inside to outside, a width of the primary coil 10 increases continuously, and a width of the secondary coil 20 remains unchanged.

[0085] In other words, the transformer according to this embodiment of this application includes the coil. A shape of the coil may be roughly spiral. In other words, the coil may be a continuously spiral member that is wound outward about a rotation center.

[0086] It should be noted that, in a manufacturing process of the coil in this embodiment of this application, the coil may be wound from inside to outside about the rotation center. In other words, an inlet end of the coil is located at the rotation center, and an outlet end of the coil is located on an outer circumference of the coil. Alternatively, the coil may be wound from outside to inside about the rotation center. In other words, an inlet end of the coil is located on an outer circumference of the coil, and an outlet end of the coil is located at the rotation center. This is not limited herein.

[0087] In addition, the coil may include the primary coil 10 and the secondary coil 20. In a winding direction starting from the rotation center from inside to outside, the width of the primary coil 10 increases continuously. In other words, a line width of the primary coil 10 gradually increases continuously in a spiral extension process. Correspondingly, the width of the primary coil 10 reduces continuously in a winding direction from outside to inside. If the entire primary coil 10 is divided into M segments in a rotation direction of the primary coil 10, each segment of the primary coil 10 has a plurality of widths instead of only one line width. In this embodiment, the primary coil 10 may be wound to form a spiral structure with one turn or a plurality of turns. This is not limited herein.

[0088] In addition, in the winding direction starting from the rotation center from inside to outside, the width of the secondary coil 20 remains unchanged. It should be noted that, by comparing a secondary coil 20 with an increasing width with the secondary coil 20 with the unchanged width that have a same quantity of turns, it can be learned that the secondary coil 20 with the unchanged width can cover a larger magnetic field range of the primary coil 10, so that a coupling effect is improved.

[0089] In this embodiment, a primary coil 10 with a gradually changed width in the spiral direction from inside to outside cooperates with the secondary coil 20 with the unchanged width, so that a coupling coefficient between the primary coil 10 and the secondary coil 20 can be improved, mutual inductance can be enhanced, and a voltage induction capability of the secondary coil 20 can be improved.

[0090] Therefore, in the transformer according to this embodiment of this application, winding line widths of the primary coil 10 and the secondary coil 20 are limited, and in the winding direction from inside to outside, a width of at least a portion of the primary coil 10 increases continuously, and the width of the secondary coil 20 remains unchanged, so that a magnetic concentration capability of the coil in the transformer can be effectively enhanced, and a coupling effect of the coil can be improved.

[0091] According to an embodiment of this application, the primary coil 10 is a multi-turn spiral conducting wire formed through winding. A terminating end of a previous turn of the conducting wire is connected to a starting end of a next turn of the conducting wire, and a width of a terminating end of at least one turn of the conducting wire is increased by A compared with that of a starting end of the at least one turn of the conducting wire. The turn of the conducting wire is divided into M segments in a winding direction of the conducting wire, and an increment of a width of each segment is A / M.

[0092] In other words, in this embodiment, the primary coil 10 is of a multi-turn spiral structure, and the primary coil 10 may be divided into N turns of conducting wires starting from the rotation center from inside to outside. The terminating end of the previous turn of conducting wire is connected to the starting end of the next turn of conducting wire. Whether a length of each turn of conducting wire is the same is not limited in this embodiment. The multi-turn conducting wire herein may be understood as that a plurality of coil portions 40 is formed through winding of the primary coil 10, each coil portion 40 has a starting end and a terminating end, and a terminating end of a previous coil portion 40 is connected to a starting end of a next coil portion 40. For example, the primary coil 10 is divided into N coil portions 40 in the winding direction, and a terminating end of an (N-1) th< coil portion 40 is connected to a starting end of an N th< coil portion 40, so that the primary coil 10 continuously extending in a spiral is formed.

[0093] In addition, a width of a starting end of at least one turn is defined as L1, and a width of a terminating end is defined as L2. In this case, an increased width of the terminating end relative to the corresponding starting end is A, where A=L2-L1. The turn of conducting wire is divided into M segments in a winding direction of the turn of conducting wire, and an increment of a width of each segment is A / M, that is, (L2-L1) / M.

[0094] In this embodiment, that the at least one turn of conducting wire is divided into M segments in the winding direction of the turn of conducting wire is limited, so that the increment of the width of each segment is A / M. In other words, the increment of the width of each segment of the at least one turn of conducting wire in the primary coil 10 is the same. The increment of the width of each segment of each turn of conducting wire is the same, so that a region in which the line width increases continuously can be expanded, to facilitate processing and manufacturing of the primary coil 10 while ensuring the magnetic concentration capability.

[0095] In some implementations of this application, a starting end corresponding to each turn of conducting wire increases gradually in width to a terminating end of the turn of the conducting wire through 360° spiral rotation. For example, a width of a starting end of a coil portion 40 is L1, and the coil portion 40 gradually increases the width by A through 360° spiral rotation from the starting end to a terminating end, and a width of the terminating end of the coil portion 40 is L1+A.

[0096] In addition, a starting end and a terminating end corresponding to each coil portion 40 correspond to each other in a radial direction of the primary coil 10. To be specific, in a radial direction starting from the rotation center from inside to outside, a starting end and a terminating end of one coil portion 40 are spaced apart and are provided relative to each other. In this case, a spacing between the starting end and the terminating end corresponding to the coil portion 40 may be defined as B, a width of the coil portion 40 is greater than or equal to 0 mm, and the spacing B between the starting end and the terminating end is greater than 0 mm. A spacing between the starting end and the terminating end corresponding to each coil portion 40 is limited to be greater than a preset spacing, to help design and process the primary coil 10.

[0097] In this embodiment, in the radial winding direction from inside to outside, a width of each coil portion 40 formed through a 360° radial rotation increases continuously, and each turn of the coil portion 40 has an infinite quantity of line widths, so that the magnetic concentration capability of the coil can be improved.

[0098] According to an embodiment of this application, a width corresponding to the terminating end of the previous coil portion 40 and a width corresponding to the starting end of the next coil portion 40 are equal or unequal. For example, when a line width of a terminating end of an N th< turn of the coil portion 40 is equal to a line width of a starting end of an (N+1) th< turn of the coil portion 40, the width is in a continuously gradual change mode. When a line width of a terminating end of an N th< turn of the coil portion 40 is unequal to a line width of a starting end of an (N+1) th< turn of the coil portion 40, the width is in a sudden change mode. Provided that a width of an original coil 20 can increase continuously in the winding direction from inside to outside in a solution, the solution falls within the protection scope of this application.

[0099] In some implementations of this application, the increased width of the terminating end corresponding to each coil portion 40 relative to the corresponding starting end is a fixed value or a value within a preset range. In other words, the increased width A of the terminating end corresponding to each coil portion 40 relative to the starting end may be the same or different. For example, A corresponding to the N th< turn of the coil portion 40 and A corresponding to the (N-1) th< turn of the coil portion 40 may be equal or unequal.

[0100] For example, as shown in FIG. 18, the primary coil 10 may be wound in the following specific manner: for a 1 st< turn of conducting wire, an initial line width W 11 is spirally increased by A 1 starting from a starting end R 1 to a terminating end R 2 , where a line width of the terminating end is W 12 =W 11 +A 1 ; for a 2 nd< turn of conducting wire, an initial line width W 21 is spirally increased by A 2 starting from a starting end R 2 to a terminating end R 3 , where W 21 is equal or unequal to W 12 , and a line width of the terminating end is W 22 =W 21 +A 2 ; for a 3 rd< turn of conducting wire, an initial line width W 31 is spirally increased by A 3 starting from a starting end R 3 to a terminating end R 4 , where W 31 may be equal or unequal to W 22 , and a line width of the terminating end is W 32 =W 31 +A 3 ; and for an N th< turn of conducting wire, an initial line width W n1 is spirally increased by A n starting from a starting end R n to a terminating end R n+1 , where W n1 may be equal or unequal to W (n-1)2 , and a line width of the terminating end is W n2 =W n1 +A n .

[0101] In some implementations of this application, at least a portion of the primary coil 10 is wound to form an arc-shaped member. In other words, in the winding direction of the primary coil 10, at least a portion of at least one coil portion 40 is an arc-shaped member. That is, arc routing is used for at least the portion of the primary coil 10 in a spiral winding process, so that EMI (electromagnetic interference) generated by right-angle routing is reduced. In addition, the spiral arc routing can reduce a capacitive load on a transmission line and also make impedance on the transmission line uniform. The arc routing is used for the entire primary coil 10. In other words, the arc routing is used for each coil portion 40, so that the EMI and the capacitive load on the transmission line can be reduced.

[0102] In this embodiment, the spiral arc routing is used, so that the EMI caused by the right-angle routing can be effectively reduced, and an uniformly increase or reduction in the line width can reduce a capacitive load of the primary coil 10, make parasitic impedance of the primary coil 10 uniform, and enhance transmission performance.

[0103] According to an embodiment of this application, the transformer further includes a board body. The board body is a multi-layer board, and the primary coil 10 and the secondary coil 20 are respectively disposed on different layers of the board. In other words, the coil is mounted on the board body, the board body is a multi-layer board, and the primary coil 10 and the secondary coil 20 are mounted on the board body. For example, a board body of a printed circuit board (PCB) may be a multi-layer board, and the coil is drawn on each layer of the printed circuit board.

[0104] In some implementations of this application, as shown in FIG. 19, a primary coil 10 is located on a top-layer board of the multi-layer board, and a secondary coil 20 is located on a bottom-layer board of the multi-layer board. The multi-layer board is provided with a first connection end H1, a primary input end H2, a secondary input end H3, and a secondary output end H4. The first connection end H1 and the primary input end H2 are connected to the primary coil 10, to form input and output ends of the primary coil 10. The secondary input end H3 and the secondary output end H4 are connected to the secondary coil 20, to form input and output ends of the secondary coil 20. In this embodiment, that the multi-layer board is provided with the first connection end H1, the primary input end H2, the secondary input end H3, and the secondary output end H4 is limited. This helps form the input and output ends of the primary coil 10, and form the input and output ends of the secondary coil 20.

[0105] According to an embodiment of this application, the first connection end H1, the primary input end H2, the secondary input end H3, and the secondary output end H4 penetrate the board body.

[0106] For example, the multi-layer board is provided with a through hole G1 and a through hole G2. The through hole G1 may allow an inlet end of the primary coil 10 to be routed to an outer circumference of the primary coil 10 through another layer of the multi-layer board. In other words, the through hole G1 may allow a starting end of the primary coil 10 located on the top-layer board to be routed to the first connection end H1 through the another layer. The through hole G2 may allow an inlet end of the secondary coil 20 to be routed to an outer circumference of the secondary coil 20 through another layer of the multi-layer board. In other words, the through hole G2 may allow a starting end of the secondary coil 20 located on the bottom-layer board to be routed to the secondary output end H4 through the another layer. The first connection end H1 and the primary input end H2 are the input and output ends of the primary coil 10, and the secondary input end H3 and the secondary output end H4 are the input and output ends of the secondary coil 20, to facilitate provision of input ends and output ends of the primary coil 10 and the secondary coil 20.

[0107] For another example, the board body includes a six-layer board. Primary coils 10 are placed on the top-layer board, a second-layer board, and a fourth-layer board of the board body, and a secondary coil 20 is placed on a third-layer board. The primary coil 10 located on the top-layer board is connected to the primary coil 10 located on the second-layer board through a through hole G3, and the primary coil 10 located on the second-layer board is connected to the primary coil 10 located on the fourth-layer board through a through hole G5, and then a winding termination end in an inner diameter of the primary coil 10 located on the fourth-layer board is connected to the first connection end H1 through a through hole G4. The secondary coil 20 is wound counterclockwise from inside to outside, and a through hole G6 allows a winding starting end of the secondary coil 20 to be routed to the secondary output end H4 through another layer.

[0108] It can be learned that, in this embodiment, that the first connection end H1, the primary input end H2, the secondary input end H3, and the secondary output end H4 penetrate the board body is limited. This helps improve diversity and flexibility of a distribution relationship between the primary coil 10 and the secondary coil 20 on the board body.

[0109] In some implementations of this application, one primary coil 10 is included. A terminating end of the primary coil 10 is connected to the primary input end H2, and a starting end of the primary coil 10 is connected to the first connection end H1 through a trace. For example, as shown in FIG. 20(a) to FIG. 20(c), the board body is a four-layer board, there are one primary coil 10, and the primary coil 10 is drawn on a topmost-layer board of the board body. The starting end of the primary coil 10 is located on the inside, and the terminating end is located on the outside. The starting end of the primary coil 10 may be routed to the first connection end H1 through another layer of the board body, and the terminating end may be connected to the primary input end H2. In this embodiment, that the terminating end of the primary coil 10 is connected to the primary input end H2 and that the starting end of the primary coil 10 is connected to the first connection end H1 through a trace are limited. This helps the first connection end H1 and the primary input end H2 form the coil input end and the coil output end of the primary coil 10, where the coil input end and the coil output end of the primary coil 10 are close to an outer side of the coil.

[0110] According to an embodiment of this application, one secondary coil 20 is included. The secondary coil 20 extends from a starting end to a terminating end of the secondary coil 20 in a spiral direction from inside to outside. The terminating end of the secondary coil 20 is connected to the secondary input end H3, and the starting end of the secondary coil 20 is connected to the secondary output end H4 through a trace. For example, as shown in FIG. 20(a) to FIG. 20(c), the board body is a four-layer board, there are one secondary coil 20, and the secondary coil 20 is drawn on a bottommost-layer board of the board body. The starting end of the secondary coil 20 is located on the inside, and the terminating end is located on the outside. The starting end of the secondary coil 20 may be routed to the secondary output end H4 through another layer of the board body, and the terminating end may be connected to the secondary input end H3. In this embodiment, that the terminating end of the secondary coil 20 of the secondary coil 20 is connected to the secondary input end H3 and that the starting end of the secondary coil 20 is connected to the secondary output end H4 through a trace are limited. This helps the secondary input end H3 and the secondary output end H4 form the coil input end and the coil output end of the secondary coil 20, where the coil input end and the coil output end of the secondary coil 20 are close to the outer side of the coil.

[0111] In some implementations of this application, one primary coil 10 is included. The terminating end of the primary coil 10 is connected to the primary input end H2, and the starting end of the primary coil 10 is connected to the first connection end H1 through a trace. In addition, one secondary coil 20 is included. The secondary coil 20 extends from the starting end to the terminating end of the secondary coil 20 in the spiral direction from inside to outside. The terminating end of the secondary coil 20 is connected to the secondary input end H3, and the starting end of the secondary coil 20 is connected to the secondary output end H4 through a trace. This helps the first connection end H1 and the primary input end H2 form the coil input end and the coil output end of the primary coil 10, and also helps the secondary input end H3 and the secondary output end H4 form the coil input end and the coil output end of the secondary coil 20.

[0112] According to an embodiment of this application, an odd quantity of primary coils 10 that are stacked and connected in series are included, where the quantity is not less than 3. A terminating end of a 1 st< primary coil 10 in a series connection direction is connected to the primary input end H2, a starting end of a last primary coil 10 is connected to the first connection end H1 through a trace, and spiral directions of adjacent primary coils 10 are opposite.

[0113] For example, as shown in FIG. 22(a) to FIG. 22(e), the board body includes a six-layer board. Primary coils 10 are respectively placed on a top-layer board, a second-layer board, and a fourth-layer board. In this case, there are three primary coils 10. The primary coil 10 located on the top-layer board is connected to the primary coil 10 located on the second-layer board through the through hole G3, and the primary coil 10 located on the second-layer board is connected to the primary coil 10 located on the fourth-layer board through the through hole G5, and then the winding termination end in the inner diameter of the primary coil 10 located on the fourth-layer board is connected to the first connection end H1 through the through hole G4. The primary coil 10 located on the top-layer board is spirally wound counterclockwise from inside to outside, the primary coil 10 located on the second-layer board is spirally wound clockwise from inside to outside, and the primary coil 10 located on the fourth-layer board is spirally wound clockwise from outside to inside, to ensure that the three primary coils 10 are connected in series.

[0114] It can be learned that, in this embodiment, that the terminating end of the 1 st< primary coil 10 in the series connection direction is connected to the primary input end H2, that the starting end of the last primary coil 10 is connected to the first connection end H1 through the trace, and that the spiral directions of the adjacent primary coils 10 are opposite are limited. This helps the odd quantity of primary coils 10 be connected in series, and the coil input end and the coil output end of the primary coil 10 be close to the outer side of the coil.

[0115] In some implementations of this application, an odd quantity of secondary coils 20 that are stacked and connected in series are included, where the quantity is not less than 3. The secondary coil 20 extends from a starting end to a terminating end of the secondary coil 20 in the spiral direction from inside to outside. A terminating end of a 1 st< secondary coil 20 in a series connection direction is connected to the secondary input end H3, a starting end of a last secondary coil 20 is connected to the secondary output end H4 through a trace, and spiral directions of adjacent secondary coils 20 in the series connection direction are opposite. This helps the odd quantity of secondary coils 20 be connected in series.

[0116] According to an embodiment of this application, the odd quantity of primary coils 10 that are stacked and connected in series are included, where the quantity is not less than 3. The terminating end of the 1 st< primary coil 10 in the series connection direction is connected to the primary input end H2, the starting end of the last primary coil 10 is connected to the first connection end H1 through the trace, and the spiral directions of the adjacent primary coils 10 are opposite. In addition, the odd quantity of secondary coils 20 that are stacked and connected in series are included, where the quantity is not less than 3. The secondary coil 20 extends from the starting end to the terminating end of the secondary coil 20 in the spiral direction from inside to outside. The terminating end of the 1 st< secondary coil 20 in the series connection direction is connected to the secondary input end H3, the starting end of the last secondary coil 20 is connected to the secondary output end H4 through the trace, and the spiral directions of the adjacent secondary coils 20 in the series connection direction are opposite. This helps the odd quantity of primary coils 10 be connected in series and the odd quantity of secondary coils 20 be connected in series, and the coil input end and the coil output end of the secondary coil 20 be close to the outer side of the coil.

[0117] In some implementations of this application, an even quantity of primary coils 10 that are stacked and connected in series are included, where the quantity is not less than 2. A terminating end of a 1 st< primary coil 10 in a series connection direction is connected to the primary input end H2, a starting end of a last primary coil 10 is connected to the first connection end H1, and spiral directions of adjacent primary coils 10 in the series connection direction are opposite.

[0118] For example, as shown in FIG. 24(a) to FIG. 24(d), the board body is a four-layer board, there are two primary coils 10, one is located on a top-layer board of the board body, and the other is located on a second-layer board of the board body. The primary coil 10 located on the top-layer board is spirally wound counterclockwise from inside to outside. A starting end of the primary coil 10 is located inside the primary coil 10, and a terminating end is located on the outside, and is connected to the primary input end H2. The primary coil 10 located on a second layer is spirally wound clockwise from inside to outside. A starting end of the primary coil 10 is located inside the primary coil 10, and a terminating end is located on the outside, and is connected to the first connection end H1.

[0119] In this embodiment, that the terminating end of the 1 st< primary coil 10 is connected to the primary input end H2, that the starting end of the last primary coil 10 is connected to the first connection end H1, and that the spiral directions of the adjacent primary coils 10 in the series connection direction are opposite are limited. This helps ensure that the even quantity of primary coils 10 are connected in series, and a coil input end and a coil output end of the primary coil 10 are close to an outer side of the coil.

[0120] According to an embodiment of this application, an even quantity of secondary coils 20 that are stacked and connected in series are included, and the quantity is not less than 2. The secondary coil 20 extends from a starting end to a terminating end of the secondary coil 20 in a spiral direction from inside to outside. A terminating end of a 1 st< secondary coil 20 in a series connection direction is connected to the secondary input end H3, and a starting end of a last secondary coil 20 is connected to the secondary output end H4.

[0121] For example, as shown in FIG. 24(a) to FIG. 24(d), the board body is a four-layer board, there are two secondary coils 20, one is located on a third-layer board of the board body, and the other is located on a bottom-layer board of the board body. The secondary coil 20 located on a third layer is spirally wound counterclockwise from inside to outside. A starting end of the secondary coil 20 is located inside the secondary coil 20, and a terminating end is located on the outside, and is connected to the secondary input end H3. The secondary coil 20 located on the bottom-layer board is spirally wound clockwise from inside to outside. A starting end of the secondary coil 20 is located inside the secondary coil 20, and a terminating end is located on the outside, and is connected to the secondary output end H4.

[0122] In this embodiment, that the terminating end of the 1 st< secondary coil 20 is connected to the secondary input end H3 and that the starting end of the last secondary coil 20 is connected to the secondary output end H4 are limited. This helps ensure that the even quantity of secondary coils 20 are connected in series, and a coil input end and a coil output end of the secondary coil 20 are close to the outer side of the coil.

[0123] In some implementations of this application, the even quantity of primary coils 10 that are stacked and connected in series are included, and the quantity is not less than 2. The terminating end of the 1 st< primary coil 10 in the series connection direction is connected to the primary input end H2, the starting end of the last primary coil 10 is connected to the first connection end H1, and the spiral directions of the adjacent primary coils 10 in the series connection direction are opposite. In addition, the even quantity of secondary coils 20 that are stacked and connected in series are included, where the quantity is not less than 2. The secondary coil 20 extends from the starting end to the terminating end of the secondary coil 20 in the spiral direction from inside to outside. The terminating end of the 1 st< secondary coil 20 in the series connection direction is connected to the secondary input end H3, and the starting end of the last secondary coil 20 is connected to the secondary output end H4. In this embodiment, connection relationships between both the even quantity of secondary coils 20 and the even quantity of primary coils 10 and the first connection end H1, the primary input end H2, the secondary input end H3, and the secondary output end H4 are all limited, so that it can be ensured that the even quantity of primary coils 10 are connected in series and that the even quantity of secondary coils 20 are connected in series.

[0124] The following describes in detail the transformer in embodiments of this application with reference to specific embodiments.Embodiment 7

[0125] A PCB is a four-layer board, and a primary winding and a secondary winding are drawn on the PCB. A primary coil 10 of the primary winding is placed on a top layer of the PCB, and a secondary coil 20 of the secondary winding is placed on a bottom layer of the PCB. The primary coil 10 and the secondary coil 20 each include 7 turns of coils, and are drawn with a same center on the four-layer PCB. In addition, a method for designing unequal-width coils is used, and each turn of coil is in a continuous increase mode. FIG. 18 shows winding of a PCB coil with unequal widths.

[0126] Other two layers of the PCB are used for routing. A through hole G1 allows a starting end of the primary coil 10 located on the top layer to be routed to a first connection end H1 through another layer. As shown in FIG. 19, FIG. 19 shows the transformer including unequal-width coils. A through hole G2 allows a starting end of the secondary coil 20 located at a bottom end to be routed to a secondary output end H4 through another layer. The first connection end H1 and a primary input end H2 are input and output ends of the primary coil 10, and a secondary input end H3 and the secondary output end H4 are input and output ends of the secondary coil 20. A routing method is shown in FIG. 20(a) to FIG. 20(c).Embodiment 8

[0127] A PCB is a six-layer board, and a primary winding and a secondary winding are drawn on the PCB. Primary coils 10 of the primary winding are placed on a top layer, a second layer, and a fourth layer of the PCB, and a secondary coil 20 of the secondary winding is placed on a third layer.

[0128] The primary coil 10 and the secondary coil 20 each include 7 turns of coils, and are drawn with a same center on the six-layer PCB. In addition, a method for designing unequal-width coils is used, and each turn of coil is in a continuous increase mode. FIG. 21 shows a structure of a transformer using a plurality of series-connected primary coils 10 with unequal-width coils. FIG. 22(a) to FIG. 22(e) show PCB traces of a plurality of series-connected primary coils 10 with unequal-width coils.

[0129] As shown in FIG. 21, the primary coil 10 located on the top layer is connected to the primary coil 10 located on the second layer through a through hole G3, and the primary coil 10 located on the second layer is connected to the primary coil 10 located on the fourth layer through a through hole G5, and then a winding termination end in an inner diameter of the primary coil 10 located on the fourth layer is connected to a first connection end H1 through a through hole G4. The primary coil 10 located on the top layer is spirally wound counterclockwise from inside to outside, the primary coil 10 located on the second layer is spirally wound clockwise from inside to outside, and the primary coil 10 located on the fourth layer is spirally wound clockwise from outside to inside, to ensure that the three primary coils 10 have consistent rotating directions and are connected in series.

[0130] The secondary coil 20 is placed on the third layer of the PCB. The secondary coil 20 is wound counterclockwise from inside to outside. A through hole G6 allows a winding starting end of a secondary coil 20 located on a bottom end to be routed to a secondary output end H4 through another layer. A first connection end H1 and a primary input end H2 are input and output ends of the primary coil 10, and a secondary input end H3 and the secondary output end H4 are input and output ends of the secondary coil 20.

[0131] A fifth layer and a sixth layer are used for routing, to lead out primary and secondary side lines at an inner diameter of the coil. A routing method is shown in FIG. 22.Embodiment 9

[0132] A PCB is a four-layer board, and a primary winding and a secondary winding are drawn on the PCB. Primary coils 10 of the primary winding are placed on a top layer and a second layer of the PCB, and secondary coils 20 of the secondary winding are placed on a third layer and a bottom layer. The primary coil 10 and the secondary coil 20 each include 7 turns of coils, and are drawn with a same center on the four-layer PCB. In addition, a method for designing unequal-width coils is used, and each turn of coil is in a continuous increase mode. FIG. 23 shows a transformer including a plurality of series-connected primary coils 10 and secondary coils 20 with unequal-width coils. FIG. 24(a) to FIG. 24(d) show PCB traces of a plurality of series-connected primary coils 10 and secondary coils 20 with unequal-width coils.

[0133] As shown in FIG. 23, the primary coil 10 located on the top layer is connected to the primary coil 10 located on the second layer through a through hole G7, the primary coil 10 located on the top layer spirally wound counterclockwise from inside to outside, and the primary coil 10 located on the second layer is spirally wound clockwise from inside to outside, to ensure that the two primary coils 10 have consistent rotating directions and are connected in series.

[0134] The secondary coils 20 are placed on the third layer and the bottom layer of the PCB. The secondary coil 20 located on the third layer is connected to the secondary coil 20 located on the bottom layer through a through hole G8, the secondary coil 20 located on the third layer spirally wound counterclockwise from inside to outside, and the secondary coil 20 located on the bottom layer is spirally wound clockwise from inside to outside, to ensure that the two secondary coils 20 have consistent rotating directions and are connected in series.

[0135] A first connection end H1 and a primary input end H2 are input and output ends of the primary coil 10, and a secondary input end H3 and a secondary output end H4 are input and output ends of the secondary coil 20. A routing method is shown in FIG. 24.Embodiment 10

[0136] As shown in FIG. 25(a), a primary coil 10 and a secondary coil 20 are combined to form a transformer. Line widths of turns in the primary coil 10 changes gradually and increases gradually, and line widths in the secondary coil 20 are the same.

[0137] The following tests transformers in a plurality of embodiments of this application.Test 1

[0138] A structure in this embodiment of this application in which line widths of turns of coils increase gradually and a structure in a conventional technology in which a line width of a coil remains unchanged but a line width of a next turn increases are compared through Q3D simulation.

[0139] Coil structures are shown in FIG. 25(a) and FIG. 25(b). The coil in FIG. 25(a) is the coil structure in which line widths of turns change gradually and increase gradually, and the coil in FIG. 25(b) is the coil structure in which line widths of turns remain unchanged and increase gradually. A comparison result is shown in Table 1. In a case in which a coil size is constant, an inductance of the coil structure in which line widths of turns change gradually and increase gradually is larger than that of the coil structure in which line widths of turns remain unchanged and increase gradually. Although resistance of the structure is larger, but an internal parasitic capacitance thereof is smaller than that of the coil structure in which line widths of turns remain unchanged and increase gradually.

[0140] Maxwell modeling is performed on the structure in this embodiment of this application in which line widths of turns of coils increase gradually and the structure in the conventional technology in which a line width of a coil remains unchanged but a line width of a next turn increases, and a topology structure of a flyback transformer is built in Simplorer for simulation. In a case in which a same primary current is ensured, a secondary output voltage is compared. As shown in FIG. 26, a line a in FIG. 26 corresponds to an output waveform diagram of a transformer including a primary coil 10 using the coil structure in which line widths of turns change gradually and increase gradually and an equal-width secondary coil 20. A line b in FIG. 26 corresponds to an output waveform diagram of a transformer including a primary coil 10 using the coil structure in which line widths of turns remain unchanged and increase gradually and an equal-width secondary coil 20. It can be learned that an output voltage of the solution according to this application in which the primary coil with the structure in which line widths of turns change gradually and increase gradually is combined with the equal-width secondary coil can reach 20 V, but an output voltage of the conventional technology in which the primary coil with the structure in which line widths of turns remain unchanged and increase gradually is combined with the equal-width secondary coil is only 17 V. Table 1Coil structure in which line widths of turns change gradually and increase graduallyCoil structure in which line widths of turns remain unchanged and increase graduallyInner diameter of a coil3.5 mm3.5 mmOuter diameter of the coil7 mm7 mmQuantity of turns55Q3D simulated inductance314.02705nH273.42368nHQ3D simulated resistance0.1036 Ω0.09898 ΩQ3D simulated capacitance0.46104 pF0.48470 pF Test 2

[0141] A primary coil 10 and a secondary coil 20 are combined to form a transformer, and four combinations are established. The four transformer combinations include: Combination 1: The primary coil 10 has equal widths, and the secondary coil 20 has equal widths; Combination 2: The primary coil 10 has equal widths, and the secondary coil 20 has unequal widths; Combination 3: Line widths of turns in the primary coil 10 change gradually and increase gradually, and the secondary coil 20 has equal widths; and Combination 4: The primary coil 10 has unequal widths, and the secondary coil 20 has unequal widths.

[0142] Equal widths mean that line widths of turns of coils are equal, and unequal widths mean that line widths of turns of coils are unequal. The primary coil with the structure in which line widths of turns change gradually and increase gradually is shown in FIG. 25(a).

[0143] The topology structure of the flyback transformer is built by using Simplorer, and joint simulation is performed by using Maxwell and Simplorer. When it is ensured that a same current flows into the primary coil 10, a secondary voltage output result is obtained, as shown in FIG. 18 and FIG. 27. In FIG. 18 and FIG. 27, a line c corresponds to Combination 1, a line d corresponds to Combination 2, a line e corresponds to Combination 3, and a line f corresponds to Combination 4. It can be learned that a secondary voltage generated by the combination of the primary coil with the structure in which line widths of turns change gradually and increase gradually is the highest, and a coupling effect of the primary coil 10 and the secondary coil 20 is optimal.

[0144] It can be learned through testing and combination that, in the printed circuit board and the transformer according to embodiments of this application, the coil structure in which a width increases gradually in a direction from inside to outside is used, so that the coupling effect of the primary coil 10 and the secondary coil 20 can be improved.

[0145] As shown in FIG. 28, a transformer 1000 according to an embodiment of this application includes a primary coil 10 and a secondary coil 20. The primary coil 10 and the secondary coil 20 are insulated from each other and magnetically coupled. The primary coil 10 extends from a first starting end 11a to a first terminating end 11b in a spiral direction from inside to outside, and the primary coil 10 includes a plurality of head-to-tail winding segments 111. The primary coil 10 has at least two line widths, and the secondary coil 20 has one line width. That the coil has at least two line widths means that the coil has at least two regions with different widths. That the coil has one line width means that widths of all parts of the coil are the same.

[0146] According to the transformer 1000 according to this embodiment of this application, the primary coil 10 in the transformer 1000 has at least two line widths, and the secondary coil 20 has one line width. Through cooperation between the primary coil 10 and the secondary coil 20, a magnetic concentration capability of the coil can be effectively enhanced, a coupling coefficient of the primary coil and the secondary coil can be improved, mutual inductance can be enhanced, and a capability of the secondary coil 20 to induce a voltage.

[0147] As shown in FIG. 31, FIG. 28 and FIG. 38, these accompanying drawings show output waveform diagrams of transformers 1000 of different forms. A waveform 1 is a waveform diagram in which the primary coil has at least two line widths and the secondary coil has one line width, a waveform 2 is a waveform diagram in which the primary coil has one line width and the secondary coil has one line width, a waveform 3 is a waveform diagram in which the primary coil has at least two line widths and the secondary coil has at least two line widths, and a waveform 4 is a waveform diagram in which the primary coil has one line width and the secondary coil has at least two line widths. It can be learned from a comparative analysis of the waveform 1, the waveform 2, the waveform 3, and the waveform 4 that, in this application, disposition in which the primary coil has at least two line widths and the secondary coil has one line width effectively improves the coupling coefficient and magnetic concentration capability of the primary coil and the secondary coil, and can have a stronger mutual inductance capability.

[0148] In addition, in this application, the primary coil 10 extends in the spiral direction from inside to outside, and a line width of a predetermined position on the primary coil 10 is the direction from inside to outside of the primary coil 10, and is perpendicular to a size of the predetermined position on the primary coil 10. The secondary coil 20 may be disposed in a stacked manner with the primary coil 10, and may be disposed to extend in the spiral direction from inside to outside. A line width of a predetermined position on the secondary coil 20 may be the direction from inside to outside of the secondary coil 20, and is perpendicular to a size of the predetermined position on the secondary coil 20.

[0149] In addition, the primary coil 10 according to this application may be flat and drawn on the circuit board, and the secondary coil 20 may also be flat and drawn on the circuit board. Certainly, overall shapes of the primary coil 10 and the secondary coil 20 may alternatively adopt another embodiment in the conventional technology.

[0150] The primary coil 10 according to this application has at least two line widths. The at least two line widths may be formed in the primary coil 10 in different forms. In this application, the following describes in detail from perspectives of a plurality of implementations, and analyzes some of the implementations. In addition, in this application, a plurality of primary coils 10 may be included, and the plurality of primary coils 10 may be connected in series and / or connected in parallel (for example, the plurality of primary coils 10 are connected in series). The plurality of primary coils 10 may have a same structure form, or at least two primary coils 10 have different structure forms. For example, when there are a plurality of primary coils 10, at least one primary coil 10 may have at least two line widths, and the plurality of primary coils 10 may also include a primary coil 10 with only one line width.

[0151] In the following different embodiments in this application, the primary coil 10 has different structure forms, so that the primary coil 10 has at least two line widths, for example, includes but is not limited to a case in which the winding segment 111 has at least two line widths, the winding segment 111 has only one line width, line widths of at least two winding segments 111 are different, or the like. Certainly, these descriptions are merely for describing the specific implementations of this application, and are not intended to limit the protection scope of this application. For example, a combination of the following different embodiments of this application may form a new implementation.Embodiment 10

[0152] As shown in FIG. 29, in some embodiments of this application, at least one winding segment 111 has at least two line widths. This includes but is not limited to: Each winding segment 111 has at least two line widths (as shown in FIG. 29 and FIG. 30); only one of a plurality of winding segments 111 has at least two line widths (as shown in FIG. 31), and other winding segments 111 have only one line width; only two of a plurality of winding segments 111 have at least two line segments (as shown in FIG. 32), and other winding segments 111 have only one line width; and the like. In addition, in the winding segment 111 having the at least two line widths, there may be two line widths, three line widths, four line widths, or the like. Through such disposition manner, a magnetic concentration capability of a coil can be optimized, a coupling coefficient of a primary coil 10 and a secondary coil 20 can be improved, and performance of a transformer 1000 can be improved.

[0153] In addition, it should be noted that FIG. 29, FIG. 30, FIG. 32, FIG. 33, and FIG. 34 are diagrams of an unfolded primary coil 10 or an unfolded winding segment 111, and structures in these diagrams may be wound from one end to the other end in a spiral direction from inside to outside to form the primary coil 10 or the winding segment 111.

[0154] With reference to FIG. 29, FIG. 30, and FIG. 34, the plurality of winding segments 111 may each have a first end and a second end. The first end of the winding segment 111 is a first line width, the second end of the winding segment 111 is a second line width, and the first line width and the second line width are different. For example, the first line width may be set to be greater than the second line width, or the first line width may be set to be less than the second line width. The winding segment 111 from the first end to the second end may be in a gradual change in line width, or may be in a sudden change in line width. For example, the first end of the winding segment 111 is the first line width, the second end is the second line width, and the first line width is less than the second line width. The winding segment 111 may be configured to have widths that increase linearly from the first end to the second end (as shown in FIG. 34). Alternatively, a step may be constructed between the first line width and the second line width of the winding segment 111, to form the sudden change in line width. The first line width and the second line width are respectively provided at two ends of the winding segment 111, to facilitate forming of the primary coil 10, so that forming efficiency of the primary coil 10 can be improved, and a magnetic coupling coefficient between the primary coil 10 and the secondary coil 20 can be improved.

[0155] In some examples, with reference to FIG. 29 and FIG. 34, the first end of the winding segment 111 is close to a first starting end 11a, and the second end of the winding segment 111 is close to a first terminating end 11b. Adjacent winding segments 111 may be respectively defined as a first winding segment 111 and a second winding segment 111. The first winding segment 111 is closer to the first starting end 11a than the second winding segment 111, and a second end of the first winding segment 111 is connected to a first end of the second winding segment. A midpoint of the first line width in a width direction may be aligned with a midpoint of the second line width in the width direction. Through such disposition, the primary coil 10 can be better coupled to the secondary coil 20 can be better coupled, and magnetic coupling performance can be improved.

[0156] In some examples, as shown in FIG. 30 and FIG. 34, starting from a first starting end 11a of the primary coil 10, a first end of an odd-numbered winding segment 111 is close to the first starting end 11a, and a second end is close to a first terminating end 11b, a first end of an even-numbered winding segment 111 is close to the first terminating end 11b, and a second end is close to the first starting end 11a. This helps a current to smoothly flow through the primary coil 10, so that the coupling coefficient between the primary coil 10 and the secondary coil 20 is improved.

[0157] Adjacent winding segments 111 may be respectively defined as a first winding segment 111 and a second winding segment 111. The first winding segment 111 is closer to the first starting end 11a than the second winding segment 111.

[0158] When the first winding segment 111 is the odd-numbered winding segment 111 and the second winding segment 111 is the even-numbered winding segment 111, a first end of the first winding segment 111 is close to the first starting end 11a, and a second end is close to the first terminating end 11b; and a first end of the second winding segment 111 is close to the first terminating end 11b, and a second end is close to the first starting end 11a. The second end of the first winding segment 111 is connected to the second end of the second winding segment 111, and the second end of the first winding segment 111 and the second end of the second winding segment 111 are both second line widths. In addition, a midpoint of the second end of the first winding segment 111 in a width direction may be aligned with a midpoint of the second end of the second winding segment 111 in the width direction.

[0159] Moreover, when the first winding segment 111 is the even-numbered winding segment 111 and the second winding segment 111 is the odd-numbered winding segment 111, a first end of the first winding segment 111 is close to the first terminating end 11b, and a second end is close to the first starting end 11a; and a first end of the second winding segment 111 is close to the first starting end 11a, and a second end is close to the first terminating end 11b. The first end of the first winding segment 111 is connected to the first end of the second winding segment 111, and the first end of the first winding segment 111 and the first end of the second winding segment 111 are both first line widths. In addition, a midpoint of the first end of the first winding segment 111 in a width direction may be aligned with a midpoint of the first end of the second winding segment 111 in the width direction.

[0160] In comparison, in a case in which it is ensured that line widths of the secondary coil 20 are equal, each turn of coil of the primary coil 10 may be divided into M segments, with each segment increasing by A, and a line width of a terminating position of each coil increases by M*A compared to a line width of the first starting end of the primary coil 10. This approximately forms a structure in which each turn of the coil increases gradually. For ease of modeling and simulation, M is set to 2, A is set to 0.08 mm, and a quantity of turns may be set to 5, as shown in FIG. 29 or FIG. 30. A topology structure of a flyback transformer 1000 is built by using Simplorer. When it is ensured that primary currents and other parameters are equal, a secondary output voltage is simulated and analyzed. As shown in FIG. 31, line widths of each winding segment 111 of the primary coil 10 change gradually and widths of the secondary coil 20 are equal (a waveform 1), widths of the primary coil 10 are equal and widths of the secondary coil 20 are equal (a waveform 2), widths of the primary coil 10 are unequal and widths of the secondary coil 20 are unequal (a waveform 3), and widths of the primary coil 10 are equal and widths of the secondary coil 20 are unequal (a waveform 4). It can be found that an output voltage of a structure in which the line widths of the primary coil 10 increase gradually or reduces gradually can reach 19 V while an output voltage of the structure in which the widths of the primary coil 10 are equal and the widths of the secondary coil 20 are equal is only 18.5 V.

[0161] With reference to the foregoing embodiments, the first line width may be set to be less than the second line width, and a line width of the winding segment 111 increases linearly in a direction from the first end to the second end. Alternatively, the first line width is greater than the second line width, and a line width of the winding segment 111 reduces linearly in a direction from the first end to the second end. This helps a current to more smoothly flow through the primary coil 10, so that the coupling coefficient between the primary coil 10 and the secondary coil 20 is improved.

[0162] Certainly, with reference to the foregoing embodiments, the winding segment 111 may alternatively be configured to have line widths that increase or reduce non-linearly in a direction from the first end to the second end.Embodiment 11

[0163] In some embodiments of this application, as shown in FIG. 35 to FIG. 28 and FIG. 37, each winding segment 111 may alternatively be configured to have only one line width, and a plurality of winding segments 111 has at least two line widths, so that a magnetic coupling coefficient between a primary coil 10 and a secondary coil 20 can be increased.

[0164] As shown in FIG. 35, in some examples, starting from a first starting end 11a of the primary coil 10, line widths of the plurality of winding segments 111 increase gradually. To be specific, each winding segment 111 has only one line width, and the line width of each winding segment 111 is consistent. As the primary coil 10 extends from inside to outside, in two adjacent winding segments 111, a line width of a winding segment 111 close to a first terminating end 11b is greater than a line width of a winding segment 111 close to a first starting end.

[0165] As shown in FIG. 36, in some examples, starting from a first starting end 11a of the primary coil 10, in two adjacent winding segments 111, a line width of an odd-numbered winding segment 111 is greater than a line width of an even-numbered winding segment 111. To be specific, each winding segment 111 has one line width, and the line width of each winding segment 111 is consistent. As the primary coil 10 extends from inside to outside, widths of a plurality of adjacent winding segments 111 change.

[0166] For example, two adjacent winding segments 111 may be respectively set as a first winding segment 111 and a second winding segment 111, the first winding segment 111 is the odd-numbered winding segment 111 counted from the first starting end 11a, and the second winding segment 111 is the even-numbered winding segment 111 counted from the first starting end. The first winding segment 111 has only a first line width, the second winding segment 111 has only a second line width, and the first line width is greater than the second line width. In addition, line widths of a plurality of winding segments 111 located at odd positions may be the same or different, and line widths of a plurality of winding segments 111 located at even positions may be the same or different.

[0167] As shown in FIG. 28 and FIG. 37, in some examples, starting from a first starting end 11a of the primary coil 10, in two adjacent winding segments 111, a line width of an odd-numbered winding segment 111 is less than a line width of an even-numbered winding segment 111. To be specific, each winding segment 111 has one line width, and the line width of each winding segment 111 is consistent. As the primary coil 10 extends from inside to outside, widths of a plurality of adjacent winding segments 111 change.

[0168] For example, two adjacent winding segments 111 may be respectively set as a first winding segment 111 and a second winding segment 111, the first winding segment 111 is the odd-numbered winding segment 111 counted from the first starting end 11a, and the second winding segment 111 is the even-numbered winding segment 111 counted from the first starting end. The first winding segment 111 has only a first line width, the second winding segment 111 has only a second line width, and the first line width is less than the second line width. In addition, line widths of a plurality of winding segments 111 located at odd positions may be the same or different, and line widths of a plurality of winding segments 111 located at even positions may be the same or different.

[0169] As shown in FIG. 28 and FIG. 38, in comparison, in a case in which it is ensured that line widths of the secondary coil 20 are equal, a line width of each turn of coil of the primary coil 10 is fixed, a line width of an N th< turn is different from a line width of an (N+1) th< turn. In this embodiment, adjacent line widths that are unequal are listed, so that a structure in which one line width is large and one line width is small is formed. As shown in FIG. 36, FIG. 28, and FIG. 37, a topology structure of a flyback transformer 1000 is built by using Simplorer. When it is ensured that primary currents and other parameters are equal, a secondary output voltage is simulated and analyzed. As shown in FIG. 28 and FIG. 38, it can be found that output of a structure in which the line widths of the primary coil 10 increase gradually or reduces gradually can reach 19.5 V while output of a structure in which widths of the primary coil are equal and widths of the secondary coil are equal is only 18.5 V. It is shown that a primary coil 10 with line widths changing irregularly generates a large output voltage, and a coupling effect of a primary coil and a secondary coil is stronger than an effect of an equal-width coil.

[0170] A waveform 1 shows a structure in which one line width of a plurality of winding segments of the primary coil is large and one is small and widths of the secondary coil are equal. A waveform 2 shows a structure in which widths of the primary coil are equal and widths of the secondary coil are equal. A waveform 3 shows a structure in which widths of the primary coil are unequal and widths of the secondary coil are unequal. A waveform 4 shows a structure in which widths of the primary coil are equal and widths of the secondary coil are unequal.

[0171] In addition, there may be another example in this application. For example, starting from the first starting end 11a of the primary coil 10, line widths of the plurality of winding segments 111 reduce gradually. To be specific, each winding segment 111 has only one line width, and the line width of each winding segment 111 is consistent. As the primary coil 10 extends from inside to outside, in two adjacent winding segments 111, a line width of a winding segment 111 close to a first terminating end 11b is less than a line width of a winding segment 111 close to a first starting end.Embodiment 12

[0172] As shown in FIG. 28 and FIG. 35, in some embodiments of this application, a line width of inner winding of a primary coil 10 is less than a line width of outer winding. The inner winding and the outer winding are relative. In other words, the inner winding is closer to a first starting end than the outer winding. In this way, when the primary coil and a secondary coil with an unchanged line width are combined, a better magnetic coupling effect can be achieved, and performance of a transformer can be improved.

[0173] The primary coil 10 may have two line widths, the inner winding has one line width, the outer winding has the other line width, and the line width of the inner winding is less than the line width of the outer winding. In addition, the primary coil 10 may alternatively have more than two line widths. As shown in FIG. 35, each winding segment has one line width, and line widths of a plurality of winding segments increase gradually from the first starting end to a first terminating end. The primary coil 10 may alternatively be configured to have line widths that increase linearly from the first starting end 11a to a first terminating end 11b.

[0174] Moreover, with reference to the foregoing embodiments, the primary coil 10 according to this application may alternatively have another disposition manner. For example, the primary coil 10 according to this application may be spiraled in a square shape, an elliptical shape, a circular shape, or another shape. As shown in FIG. 28, in some embodiments of this application, the primary coil 10 is spirally wound and has arc routing. This reduces EMI generated by right-angle routing. In addition, the spiral arc routing can reduce a capacitive load on a transmission line, make parasitic impedance of the coil uniform, and enhance transmission performance.

[0175] In some embodiments of this application, a plurality of primary coils 10 are included, and the plurality of primary coils 10 are stacked and connected in series. Therefore, a larger magnetic coupling coefficient can be achieved, and the performance of the transformer 1000 can be improved.

[0176] When the primary coil 10 extends in a spiral direction, a segment of a predetermined length on the primary coil 10 may be selected as a winding segment 111. For example, a center of the spiral direction is taken as an origin, and a plurality of winding segments 111 have a same central angle, or at least two of a plurality of winding segments 111 has different central angles. When a center of the primary coil 10 is taken as the origin, the central angle of the winding segment 111 may be greater than 0°. For example, the central angle corresponding to the winding segment 111 is set to 30°, 80°, 180°, 360°, 480°, or the like. In an embodiment of this application, at least a portion of the plurality of winding segments 111 is a circle extending in the spiral direction. The winding segment 111 has a first end and a second end, the first end of the winding segment is close to the first starting end, and the second end is close to the first terminating end. The second end of the winding segment is located outside the first end, and has a gap of a predetermined size. Therefore, an electromagnetic induction effect of the primary coil 10 can be improved, so that the primary coil 10 and a secondary coil 20 have a larger magnetic coupling coefficient.

[0177] As shown in FIG. 28, FIG. 39 to FIG. 28, and FIG. 44, in some embodiments of this application, the transformer 1000 further includes a substrate (not directly shown in the figure), and the primary coil 10 and the secondary coil 20 are both printed on the substrate. Through coil winding, a volume of the transformer 1000 can be reduced, so that a smaller transformer 1000 can be constructed. This better conforms to miniaturization of an electronic component, and effectively ensures the performance of the transformer 1000.

[0178] For ease of molding of the transformer 1000, the substrate in this application may be configured as a multi-layer board, and the primary coil 10 and the secondary coil 20 are disposed on different layers of the board, to increase the magnetic coupling coefficient and improve the performance. Different implementations may be used to change a form of the transformer 1000. Certainly, this should not be construed as a limitation on the protection scope of this application. In addition, these embodiments may be combined to form a new embodiment. For example, a combination of one group of primary coils 10 and a plurality of groups of secondary coils 20 is disposed, and different secondary coils 20 and primary coils 10 have different coupling forms, or different secondary coils 20 and primary coils 10 have a same coupling form; for another example, a plurality of groups of primary coils 10 and a plurality of groups of secondary coils 20 are disposed, and different primary coils 10 and secondary coils 20 have different coupling forms, or different primary coils 10 and secondary coils 20 have a same coupling form; or the like.

[0179] In some embodiments of this application, the substrate is a multi-layer board, the primary coil 10 and the secondary coil 20 are respectively disposed on different layers of the board. The substrate is provided with a primary output end H1, a primary input end H2, a secondary input end H3, and a secondary output end H4. The primary output end H1 and the primary input end H2 are connected to the primary coil 10, to form input and output ends of the primary coil 10. The secondary input end H3 and the secondary output end H4 are connected to the secondary coil 20, to form input and output ends of the secondary coil 20. Through layered disposition, molding efficiency of the transformer 1000 can be improved, and the magnetic coupling coefficient can be improved. In addition, input and output of electric energy can be implemented through the connection end, routing can be facilitated through the multi-layer board, and the performance of the transformer 1000 can be optimized.

[0180] As shown in FIG. 28, FIG. 39, FIG. 28, and FIG. 40, in some examples, one primary coil 10 may be included, the first starting end 11a of the primary coil 10 is connected to the primary output end H1 through a trace, and the first terminating end 11b of the primary coil 10 is connected to the primary input end H2. Therefore, this can help lead out the starting end of the primary coil 10 through the trace, so that the primary coil 10 can be better connected to an external circuit, the performance of the transformer 1000 can be optimized, and cable connection of the transformer 1000 can be facilitated.

[0181] As shown in FIG. 28, FIG. 39, FIG. 28, and FIG. 40, in some examples, one secondary coil 20 may also be included. The secondary coil 20 extends from a second starting end 12a to a second terminating end 12b in a spiral direction from inside to outside, the second terminating end 12b of the secondary coil 20 is connected to the secondary input end H3, and the second starting end 12a of the secondary coil 20 is connected to the secondary output end H4 through a trace. Therefore, this can help lead out the second starting end 12a of the secondary coil 20 through the trace, so that the secondary coil 20 can be better connected to an external circuit, the performance of the transformer 1000 can be optimized, and cable connection of the transformer 1000 can be facilitated.

[0182] As shown in FIG. 28, FIG. 41, FIG. 28, and FIG. 42, in some examples, an odd quantity of primary coils 10 that are stacked and connected in series are included, and the quantity of primary coils 10 is not less than 3. A first terminating end 11b of a 1 st< primary coil 10 in a series connection direction is connected to the primary input end H2, a first starting end 11a of a last primary coil 10 is connected to the primary output end H1 through the trace, and spiral directions of adjacent primary coils 10 in the series connection direction are opposite. The plurality of primary coils 10 are connected in series, so that a larger magnetic coupling coefficient can be provided, and therefore, the performance of the transformer 1000 is improved. In addition, when the odd quantity of primary coils 10 are used, input and output ends of the primary coil 10 are located at the first starting end 11a corresponding to the primary coil 10. In this application, the trace is used for leading, so that the performance of the transformer 1000 can be optimized.

[0183] In addition, the odd quantity of primary coils 10 according to this application may be disposed on different layers of the substrate, and the primary coils 10 are electrically connected by providing an opening on the board. Three primary coils 10 may be included, namely, a first primary coil 10, a second primary coil 10, and a third primary coil 10. The first primary coil 10, the second primary coil 10, and the third primary coil 10 are stacked. A first terminating end 11b of the first primary coil 10 may be connected to the primary input end H2, a first starting end 11a of the first primary coil 10 may be connected to a first starting end 11a of the second primary coil 10, a first terminating end 11b of the second primary coil 10 may be connected to a first terminating end 11b of the third primary coil 10, a first starting end 11a of the third primary coil 10 is connected to the primary output end H1 through the trace, and the primary output end H1 and the primary input end H2 are used as the input and output ends of the primary coil 10. The first primary coil 10 may be spiraled counterclockwise in a direction from inside to outside, the second primary coil 10 may be spiraled clockwise in the direction from inside to outside (in other words, spiraled counterclockwise in a direction from outside to inside), and the third primary coil 10 may be spiraled counterclockwise in the direction from inside to outside, so that, after the first primary coil 10, the second primary coil 10, and the third primary coil 10 are connected in series, induced magnetic field directions of the primary coils 10 are the same when a current passes through the first primary coil 10, the second primary coil 10, and the third primary coil 10.

[0184] In some examples, an odd quantity of secondary coils 20 that are stacked and connected in series are included, and the quantity of secondary coils 20 is not less than 3. The secondary coil 20 extends from the second starting end 12a to the second terminating end 12b in a spiral direction from inside to outside. A second terminating end 12b of a 1 st< secondary coil 20 in a series connection direction is connected to the secondary input end H3, a second starting end 12a of a last secondary coil 20 is connected to the secondary output end H4 through a trace, and spiral directions of adjacent secondary coils 20 in the series connection direction are opposite. The plurality of secondary coils 20 are connected in series, so that a larger magnetic coupling coefficient can be provided, and therefore, the performance of the transformer 1000 is improved. In addition, when the odd quantity of secondary coils 20 are used, input and output ends of the secondary coil 20 are located at the second starting end 12a corresponding to the secondary coil 20. In this application, the trace is used for leading, so that the performance of the transformer 1000 can be optimized.

[0185] In addition, the odd quantity of secondary coils 20 according to this application may be disposed on different layers of the substrate, and the secondary coils 20 are electrically connected by providing an opening on the board. Three secondary coils 20 may be included, namely, a first secondary coil 20, a second secondary coil 20, and a third secondary coil 20. The first secondary coil 20, the second secondary coil 20, and the third secondary coil 20 are stacked. A second terminating end 12b of the first secondary coil 20 may be connected to the primary output end H1, a second starting end 12a of the first secondary coil 20 may be connected to a second starting end 12a of the second secondary coil 20, a second terminating end 12b of the second secondary coil 20 may be connected to a second terminating end 12b of the third secondary coil 20, a second starting end 12a of the third secondary coil 20 is connected to the primary input end H2 through the trace, and the primary output end H1 and the primary input end H2 are used as the input and output ends of the secondary coil 20. The first secondary coil 20 may be spiraled counterclockwise in a direction from inside to outside, the second secondary coil 20 may be spiraled clockwise in the direction from inside to outside (in other words, spiraled counterclockwise in a direction from outside to inside), and the third secondary coil 20 may be spiraled counterclockwise in the direction from inside to outside, so that, after the first secondary coil 20, the second secondary coil 20, and the third secondary coil 20 are connected in series, induced magnetic field directions of the secondary coils 20 are the same when a current passes through the first secondary coil 20, the second secondary coil 20, and the third secondary coil 20.

[0186] As shown in FIG. 28, FIG. 43, FIG. 28, and FIG. 44, in some examples, an even quantity of primary coils 10 that are stacked and connected in series are included, and the quantity of primary coils 10 is not less than 2. A first terminating end 11b of a 1 st< primary coil 10 in a series connection direction is connected to the primary output end H1, a first starting end 11a of a last primary coil 10 is connected to the primary input end H2, and spiral directions of adjacent primary coils 10 in the series connection direction are opposite.

[0187] In addition, the even quantity of primary coils 10 according to this application may be disposed on different layers of the substrate, and the primary coils 10 are electrically connected by providing an opening on the board. Two primary coils 10 may be included, namely, a first primary coil 10 and a second primary coil 10. The first primary coil 10 and the second primary coil 10 are stacked. A first terminating end 11b of the first primary coil 10 may be connected to the primary input end H2, a first starting end 11a of the first primary coil 10 may be connected to a first starting end 11a of the second primary coil 10, a first terminating end 11b of the second primary coil 10 may be connected to the primary output end H1, and the primary output end H1 and the primary input end H2 are used as the input and output ends of the primary coil 10. The first primary coil 10 may be spiraled counterclockwise in a direction from inside to outside, and the second primary coil 10 may be spiraled clockwise in the direction from inside to outside (in other words, spiraled counterclockwise in a direction from outside to inside), so that, after the first primary coil 10 and the second primary coil 10 are connected in series, induced magnetic field directions of the primary coils 10 are the same when a current passes through the first primary coil 10 and the second primary coil 10.

[0188] As shown in FIG. 28, FIG. 43, FIG. 28, and FIG. 44, in some examples, an even quantity of secondary coils 20 that are stacked and connected in series are included, and the quantity of secondary coils 20 is not less than 2. The secondary coil 20 extends from the second starting end 12a to the second terminating end 12b in a spiral direction from inside to outside. A second terminating end 12b of a 1 st< secondary coil 20 in a series connection direction is connected to the secondary input end H3, and a second starting end 12a of a last secondary coil 20 is connected to the secondary output end H4.

[0189] In addition, the even quantity of secondary coils 20 according to this application may be disposed on different layers of the substrate, and the secondary coils 20 are electrically connected by providing an opening on the board. Two secondary coils 20 may be included, namely, a first secondary coil 20 and a second secondary coil 20. The first secondary coil 20 and the second secondary coil 20 are stacked. A second terminating end 12b of the first secondary coil 20 may be connected to the secondary input end H3, a second starting end 12a of the first secondary coil 20 may be connected to a second starting end 12a of the second secondary coil 20, a second terminating end 12b of the second secondary coil 20 may be connected to the secondary output end H4, and the secondary input end H3 and the secondary output end H4 are used as the input and output ends of the secondary coil 20. The first secondary coil 20 may be spiraled counterclockwise in a direction from inside to outside, and the second secondary coil 20 may be spiraled clockwise in the direction from inside to outside (in other words, spiraled counterclockwise in a direction from outside to inside), so that, after the first secondary coil 20 and the second secondary coil 20 are connected in series, induced magnetic field directions of the secondary coils 20 are the same when a current passes through the first secondary coil 20 and the second secondary coil 20.

[0190] The foregoing different implementation solutions may be combined to obtain a structure of the transformer 1000. This application provides several implementations based on the foregoing descriptions, but this is not a limitation on the protection scope of this application.Embodiment 10

[0191] As shown in FIG. 28, FIG. 39, FIG. 28, and FIG. 40, an unequal-width coil design method is used for a primary coil 10. A plurality of winding segments 111 of the primary coil 10 in a direction from inside to outside are in a continuous increase mode, and each winding segment 111 is one turn that surrounds one circle. A substrate is of a four-layer circuit board structure, a plurality of turns of primary coils 10 with a same circle center and a plurality of turns of secondary coils 20 with a same circle center are drawn on the substrate, the primary coil 10 is placed on a first layer, the secondary coil 20 is placed on a fourth layer, and the other two layers are used for routing. A through hole G1 allows a first starting end 11a of the primary coil 10 located on the first layer to be routed to H1 through the another layer, a through hole G2 allows a starting end of the secondary coil 20 located on the fourth layer to be routed to H4 through the another layer, H1 and H2 are input and output ends of the primary coil 10, and H3 and H4 are input and output ends of the secondary coil 20, as shown in FIG. 28 and FIG. 39. A routing method is shown in FIG. 28 and FIG. 40.

[0192] FIG. 28 and FIG. 40 show coil disposition forms on different layers of the board. The primary coil 10 is drawn on the first layer, a first terminating end 11b of the primary coil 10 is connected to a primary input end H2, and the first starting end 11a of the primary coil 10 penetrates from the through hole G1, and is connected to a primary output end H1 through a trace of an intermediate layer. The secondary coil 20 is drawn on the fourth layer, a second terminating end 12b of the secondary coil 20 is connected to a secondary input end H3, and the first terminating end 11b of the secondary coil 20 penetrates from the through hole G2, and is connected to a secondary output end H4 through a trace of the intermediate layer. The intermediate layer is a second layer and a third layer, which are stacked between the first layer and the fourth layer.Embodiment 11

[0193] As shown in FIG. 28, FIG. 41, FIG. 28, and FIG. 42, an unequal-width coil design method is used for a primary coil 10. A plurality of winding segments 111 of the primary coil 10 in a direction from inside to outside are in a continuous increase mode, and seven turns of primary coils and secondary coils 20 with a same circle center are drawn on a six-layer board. Primary coils 10 are placed on a first layer, a second layer, and a fourth layer, the primary coil 10 on the first layer is connected to the primary coil 10 located on the second layer through a through hole G3, the primary coil 10 located on the second layer is connected to the primary coil 10 located on the fourth layer through a through hole G5, and a first starting end of the primary coil 10 located on the fourth layer is connected to H1 through a through hole G4. The primary coil 10 located on the first layer is spirally wound counterclockwise from inside to outside, the primary coil 10 located on the second layer is spirally wound clockwise from inside to outside, and the primary coil 10 located on the fourth layer is spirally wound clockwise from outside to inside, to ensure that the three primary coils 10 have consistent current directions and are connected in series. The secondary coil 20 is placed on a third layer. The secondary coil 20 is wound counterclockwise from inside to outside. A through hole G6 allows a second starting end 12a of the secondary coil 20 located on the third layer to be routed to H4 through another layer. H1 and H2 are input and output ends of the primary coil 10, and H3 and H4 are input and output ends of the secondary coil 20, as shown in FIG. 28 and FIG. 41, a fifth layer and a sixth layer are used for routing, to lead out primary and secondary side lines at an inner diameter of the coil. A routing method is shown in FIG. 28 and FIG. 42.Embodiment 12

[0194] As shown in FIG. 28, FIG. 43, FIG. 28, and FIG. 44, an unequal-width coil design method is used for a primary coil 10. A plurality of winding segments 111 of the primary coil 10 in a direction from inside to outside are in a continuous increase mode, and seven turns of primary coils and secondary coils 20 with a same circle center are drawn on a four-layer board. Primary coils 10 are placed on a first layer and a second layer, and the primary coil 10 located on the first layer is connected to the primary coil 10 located on the second layer through a through hole G7. The primary coil 10 located on the first layer is spirally wound counterclockwise from inside to outside, and the primary coil 10 located on the second layer is spirally wound clockwise from inside to outside, to ensure that the two primary coils 10 have consistent current directions and are connected in series. The secondary coils 20 are placed on a third layer and a bottom layer. The secondary coil 20 located on the third layer is connected to the secondary coil 20 located on the fourth layer through a through hole G8, the secondary coil 20 located on the third layer spirally wound counterclockwise from inside to outside, and the secondary coil 20 located on the fourth layer is spirally wound clockwise from inside to outside, to ensure that the two secondary coils 20 have consistent current directions and are connected in series. As shown in FIG. 28 and FIG. 43, H1 and H2 are input and output ends of the primary coil 10, and H3 and H4 are input and output ends of the secondary coil 20. A routing method is shown in FIG. 28 and FIG. 44.

[0195] In addition, with reference to the foregoing embodiments, as shown in FIG. 28, FIG. 39 to FIG. 28, and FIG. 44, the primary output end H1, the primary input end H2, the secondary input end H3, and the secondary output end H4 are provided around outer sides of the primary coil 10 and the secondary coil 20. This can facilitate cable connection of the primary output end H1, the primary input end H2, the secondary input end H3, and the secondary output end H4, reduce impact of cables on performance of a transformer 1000, so that cable connection is facilitated, and the performance of the transformer 1000 can be optimized.

[0196] As described above, the primary coil 10 and the secondary coil 20 may extend from inside to outside in a spiral direction. In some embodiments, a first starting end 11a of the primary coil 10 and a second starting end 12a of the secondary coil 20 may be led out through routing, to facilitate connection between the primary coil 10 and both the primary output end H1 and a second connection segment and facilitate connection between the secondary coil 20 and both the secondary input end H3 and the secondary output end H4. Therefore, when a plurality of connection ends are provided around the outer sides of the primary coil 10 and the secondary coil 20, the connection ends can also be connected to the primary coil 10 and the secondary coil 20.

[0197] In the descriptions of this application, it should be understood that orientation or position relationships indicated by the terms such as "center", "width", "inner", "outer", "clockwise", and "counterclockwise" are based on orientation or position relationships shown in the accompanying drawings, and are merely intended to describe this application and simplify the descriptions, but are not intended to indicate or imply that an indicated apparatus or element needs to have a specific orientation or be constructed and operated in a specific orientation. Therefore, such terms should not be understood as a limitation on this application.

[0198] In addition, the terms "first" and "second" are merely intended for a purpose of description, and shall not be understood as an indication or implication of relative importance or implicit indication of a quantity of indicated technical features. Therefore, a feature limited by "first" or "second" may explicitly or implicitly include one or more features. In the descriptions of this application, unless otherwise specifically limited, "a plurality of" means two or more.

[0199] In this application, unless otherwise specified and limited, the terms such as "mount", "interconnect", "connect", and "fasten" should be understood in a broad sense. For example, the term may indicate a fixed connection, a detachable connection, or an integrated connection; may indicate a mechanical connection or an electrical connection; or may indicate a direct connection, an indirect connection through an intermediate medium, or internal communication between two elements or an interaction relationship between two elements. A person of ordinary skill in the art may understand specific meanings of the foregoing terms in this application based on specific situations.

[0200] In this application, unless otherwise specified and limited, that a first feature is "above" or "below" a second feature may be that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. In addition, that the first feature is "above", "over", or "on" the second feature may be that the first feature is right above or obliquely above the second feature, or merely mean that a horizontal height of the first feature is greater than that of the second feature. That the first feature is "below", "under", or "underneath" the second feature may be that the first feature is right below or obliquely below the second feature, or merely mean that the horizontal height of the first feature is less than that of the second feature.

[0201] Although embodiments of this application have been shown and described above, it may be understood that the foregoing embodiments are examples and should not be construed as a limitation on this application. A person of ordinary skill in the art may make changes, modifications, replacement, and variations to the foregoing embodiments within the scope of this application.

Claims

1. A PCB transformer coil board, comprising: a Q-layer PCB; and P coupled coil groups, the coupled coil group is disposed on the PCB, and each coupled coil group comprises two primary coils and one secondary coil disposed between the two primary coils, wherein P is an integer greater than 0; when P is an even number, Q=3P, or when P is an odd number, Q=3P+1; and an inlet end and an outlet end of the secondary coil on at least one layer of the PCB are separately provided on an outer circumference of the secondary coil.

2. The PCB transformer coil board according to claim 1, wherein a line width of the primary coil is greater than a line width of the secondary coil.

3. The PCB transformer coil board according to claim 1 or 2, wherein a quantity of turns of the secondary coil in each coupled coil group is greater than a quantity of turns of the corresponding primary coil.

4. The PCB transformer coil board according to any one of claims 1 to 3, wherein in each coupled coil group, an inlet end of one primary coil is provided within an inner circumference, an outlet end of the primary coil is provided on an outer circumference, an inlet end of the other primary coil is provided on the outer circumference, an outlet end of the other primary coil is provided within the inner circumference, the outlet end of the primary coil is connected in series to the inlet end of the other primary coil through a first via on an inner side of the primary coil.

5. The PCB transformer coil board according to claim 4, wherein in two adjacent coupled coil groups, two adjacent primary coils are connected in series through a second via on an outer side of the primary coil, an inlet end of a secondary coil in one of the coupled coil groups is provided on an outer circumference, an inlet end of a secondary coil in the other of the coupled coil groups is provided within an inner circumference, and two adjacent secondary coils are connected in series through a third via.

6. The PCB transformer coil board according to claim 5, wherein the first via, the second via, and the third via are spaced apart on the PCB.

7. The PCB transformer coil board according to claim 5 or 6, wherein the PCB is provided with a primary input end, a primary output end, a secondary input end, and a secondary output end, the primary coil is connected to the primary input end and the primary output end, and the secondary coil is connected to the secondary input end and the secondary output end.

8. The PCB transformer coil board according to claim 7, wherein the PCB comprises a first layer, a second layer, a third layer, and a fourth layer, the primary coil comprises a first coil disposed on the first layer and a second coil disposed on the third layer, and the secondary coil comprises a third coil disposed on the second layer and a connection cable disposed on the fourth layer, wherein an inlet end of the first coil is connected to the primary input end, an outlet end of the first coil is connected to an inlet end of the second coil through the first via, an outlet end of the second coil is connected to the primary output end, an inlet end of the third coil is connected to the secondary input end, an outlet end of the third coil is connected to an inlet end of the connection cable, and an outlet end of the connection cable is connected to the secondary output end.

9. The PCB transformer coil board according to claim 7, wherein the PCB comprises a first layer, a second layer, a third layer, a fourth layer, a fifth layer, and a sixth layer, the primary coil comprises a first coil, a second coil, a third coil, and a fourth coil that are sequentially disposed on the first layer, the third layer, the fourth layer, and the sixth layer, the secondary coil comprises a fifth coil and a sixth coil that are sequentially disposed on the second layer and the fifth layer, and there are two first vias, wherein an inlet end of the first coil is connected to the primary input end, an outlet end of the first coil is connected to an inlet end of the second coil through one first via, an outlet end of the second coil is connected to an inlet end of the third coil through the second via, an outlet end of the third coil is connected to an inlet end of the fourth coil through the other first via, an outlet end of the fourth coil is connected to the primary output end, an inlet end of the fifth coil is connected to the secondary input end, an outlet end of the fifth coil is connected to an inlet end of the sixth coil through the third via, and an outlet end of the sixth coil is connected to the secondary output end.

10. A PCB transformer, comprising the PCB transformer coil board according to any one of claims 1 to 9.

11. A PCB transformer, comprising a coil, wherein the coil comprises a primary coil and a secondary coil, the coil extends from a starting end to a terminating end in a spiral direction from inside to outside, and in the spiral direction from inside to outside, a width of the primary coil increases continuously, and a width of the secondary coil remains unchanged.

12. The PCB transformer according to claim 11, the primary coil is a multi-turn spiral conducting wire formed through winding, a terminating end of a previous turn of the conducting wire is connected to a starting end of a next turn of the conducting wire, a width of a terminating end of at least one turn of the conducting wire is increased by A compared with that of a starting end of the at least one turn of the conducting wire, the turn of the conducting wire is divided into M segments in a winding direction of the conducting wire, and an increment of a width of each segment is A / M.

13. The PCB transformer according to claim 12, wherein a starting end corresponding to each turn of the conducting wire increases gradually in width to a terminating end of the turn of the conducting wire through 360° spiral rotation.

14. The PCB transformer according to any one of claims 11 to 13, wherein at least a portion of the primary coil is wound to form an arc-shaped member.

15. The PCB transformer according to any one of claims 11 to 14, further comprising a board body, wherein the board body is a multi-layer board, and the primary coil and the secondary coil are respectively disposed on different layers of the board.

16. The PCB transformer according to claim 15, wherein one primary coil is located on a top-layer board of the multi-layer board, one secondary coil is located on a bottom-layer board of the multi-layer board, the multi-layer board is provided with a primary output end, a primary input end, a secondary input end, and a secondary output end, the primary output end and the primary input end are connected to the primary coil, to form input and output ends of the primary coil, and the secondary input end and the secondary output end are connected to the secondary coil, to form input and output ends of the secondary coil.

17. The PCB transformer according to claim 16, wherein the primary output end, the primary input end, the secondary input end, and the secondary output end penetrate the board body.

18. The PCB transformer according to claim 16, wherein one primary coil is comprised, a terminating end of the primary coil is connected to the primary input end, and a starting end of the primary coil is connected to the primary output end through a trace; and / or one secondary coil is comprised, the secondary coil extends from a starting end to a terminating end of the secondary coil in the spiral direction from inside to outside, the terminating end of the secondary coil is connected to the secondary input end, and the starting end of the secondary coil is connected to the secondary output end through a trace.

19. The PCB transformer according to claim 16, wherein an odd quantity of primary coils that are stacked and connected in series are comprised, the quantity is not less than 3, a terminating end of a 1st primary coil in a series connection direction is connected to the primary input end, a starting end of a last primary coil is connected to the primary output end through a trace, and spiral directions of adjacent primary coils are opposite; and / or an odd quantity of secondary coils that are stacked and connected in series are comprised, the quantity is not less than 3, the secondary coil extends from a starting end to a terminating end of the secondary coil in the spiral direction from inside to outside, a terminating end of a 1st secondary coil in a series connection direction is connected to the secondary input end, a starting end of a last secondary coil is connected to the secondary output end through a trace, and spiral directions of adjacent secondary coils in the series connection direction are opposite.

20. The PCB transformer according to claim 16,wherein an even quantity of primary coils that are stacked and connected in series are comprised, the quantity is not less than 2, a terminating end of a 1st primary coil in a series connection direction is connected to the primary input end, a starting end of a last primary coil is connected to the primary output end, and spiral directions of adjacent primary coils in the series connection direction are opposite; and / or an even quantity of secondary coils that are stacked and connected in series are comprised, the quantity is not less than 2, the secondary coil extends from a starting end to a terminating end of the secondary coil in the spiral direction from inside to outside, a terminating end of a 1st secondary coil in a series connection direction is connected to the secondary input end, and a starting end of a last secondary coil is connected to the secondary output end.

21. The PCB transformer according to any one of claims 11 to 20, comprising the PCB transformer coil board according to any one of claims 1 to 9.

22. A PCB transformer, comprising a primary coil and a secondary coil, wherein the primary coil and the secondary coil are insulated from each other and magnetically coupled, the primary coil extends from a first starting end to a first terminating end in a spiral direction from inside to outside, and comprises a plurality of head-to-tail winding segments, the primary coil has at least two line widths, and the secondary coil has one line width.

23. The PCB transformer according to claim 22, wherein at least one of the winding segments has at least two line widths.

24. The PCB transformer according to claim 23, wherein each of the winding segments has a first end and a second end, the first end of the winding segment has a first line width, the second end has a second line width, and the first line width and the second line width are different.

25. The PCB transformer according to claim 24, wherein the first end of the winding segment is close to the first starting end, and the second end is close to the first terminating end; or starting from the first starting end of the primary coil, a first end of an odd-numbered winding segment is close to the first starting end, and a second end is close to the first terminating end, a first end of an even-numbered winding segment is close to the first terminating end, and a second end is close to the first starting end.

26. The PCB transformer according to claim 24 or 25, wherein the first line width is less than the second line width, and a line width of the winding segment increases linearly in a direction from the first end to the second end.

27. The PCB transformer according to claim 22, wherein each of the winding segments has one line width, and the plurality of winding segments has at least two line widths.

28. The PCB transformer according to claim 27, wherein starting from the first starting end of the primary coil, the line widths of the plurality of winding segments increase gradually; starting from the first starting end of the primary coil, in two adjacent winding segments, a line width of an odd-numbered winding segment is greater than a line width of an even-numbered winding segment; or starting from the first starting end of the primary coil, in two adjacent winding segments, a line width of an odd-numbered winding segment is less than a line width of an even-numbered winding segment.

29. The PCB transformer according to claim 22, wherein a line width of inner winding of the primary coil is less than a line width of outer winding.

30. The PCB transformer according to claim 22, wherein the primary coil is spirally wound and has arc routing.

31. The PCB transformer according to claim 22, wherein the primary coil comprises a plurality of primary coils, and the plurality of primary coils are stacked and connected in series.

32. The PCB transformer according to claim 22, wherein at least a portion of the plurality of winding segments is a circle extending in the spiral direction, the winding segment has a first end and a second end, the first end of the winding segment is close to the first starting end, the second end is close to the first terminating end, and the second end of the winding segment is located outside the first end, and has a gap of a predetermined size.

33. The PCB transformer according to any one of claims 22 to 25 and claims 27 to 32, the PCB transformer further comprises a substrate, and the primary coil and the secondary coil are both printed on the substrate.

34. The PCB transformer according to claim 33, wherein the substrate is a multi-layer board, the primary coil and the secondary coil are respectively disposed on different layers of the board, the substrate is provided with a primary output end, a primary input end, a secondary input end, and a secondary output end, the primary output end and the primary input end are connected to the primary coil, to form input and output ends of the primary coil, and the secondary input end and the secondary output end are connected to the secondary coil, to form input and output ends of the secondary coil.

35. The PCB transformer according to claim 34, wherein one primary coil is comprised, a first terminating end of the primary coil is connected to the primary input end, and a first starting end of the primary coil is connected to the primary output end through a trace; and / or one secondary coil is comprised, the secondary coil extends from a second starting end to a second terminating end in the spiral direction from inside to outside, the second terminating end of the secondary coil is connected to the secondary input end, and the second starting end of the secondary coil is connected to the secondary output end through a trace.

36. The PCB transformer according to claim 34, wherein an odd quantity of primary coils that are stacked and connected in series are comprised, the quantity is not less than 3, a first terminating end of a 1st primary coil in a series connection direction is connected to the primary input end, a first starting end of a last primary coil is connected to the primary output end through a trace, and spiral directions of adjacent primary coils are opposite; and / or an odd quantity of secondary coils that are stacked and connected in series are comprised, the quantity is not less than 3, the secondary coil extends from a second starting end to a second terminating end in the spiral direction from inside to outside, a second terminating end of a 1st secondary coil in a series connection direction is connected to the secondary input end, a second starting end of a last secondary coil is connected to the secondary output end through a trace, and spiral directions of adjacent secondary coils in the series connection direction are opposite.

37. The PCB transformer according to claim 34, wherein an even quantity of primary coils that are stacked and connected in series are comprised, the quantity is not less than 2, a first terminating end of a 1st primary coil in a series connection direction is connected to the primary input end, a first starting end of a last primary coil is connected to the primary output end, and spiral directions of adjacent primary coils in the series connection direction are opposite; and / or an even quantity of secondary coils that are stacked and connected in series are comprised, the quantity is not less than 2, the secondary coil extends from a second starting end to a second terminating end in the spiral direction from inside to outside, a second terminating end of a 1st secondary coil in a series connection direction is connected to the secondary input end, and a second starting end of a last secondary coil is connected to the secondary output end.

38. The PCB transformer according to claim 34, wherein the primary output end, the primary input end, the secondary input end, and the secondary output end are provided around outer sides of the primary coil and the secondary coil.

39. The PCB transformer according to any one of claims 22 to 38, comprising the PCB transformer coil board according to any one of claims 1 to 9.

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