Magnetic element and circuit board assembly using same

Abstract

The invention provides a magnetic element and a circuit board assembly using the same. The magnetic element comprises a bottom plate, a cover plate, a first wrapping post, a second wrapping post, a primary winding and a secondary winding. The cover plate and the bottom plate are oppositely arranged. The first wrapping post is arranged between the bottom plate and the cover plate. The second wrapping post is arranged between the bottom plate and the cover plate. The primary winding is wound on the first wrapping post. The secondary winding is wound on the second wrapping post.

Description

TECHNICAL FIELD

[0001] The present application relates to a magnetic element and a circuit board assembly using the same. BACKGROUND

[0002] Isolation type DC-DC converters are widely used in charging heads, server power supplies, vehicle-mounted power supplies, and charging piles. Compared with other isolation type DC-DC converters, LLC series resonant converters have the characteristics of flexible switching in the full load range, and can effectively reduce the switching loss of switches under high-frequency switching conditions.

[0003] A typical LLC series resonant converter includes a magnetic element with a primary side coil and a secondary side coil. The magnetic element occupies the main space of the LLC series resonant converter. Therefore, how to provide a magnetic element that can reduce the overall size while maintaining good energy conversion efficiency and an LLC series resonant converter with the magnetic element is one of the efforts of the technical field. SUMMARY

[0004] The present application relates to a magnetic element and a circuit board assembly using the same, which can improve the above-mentioned problems.

[0005] One embodiment of the present application provides a magnetic element. The magnetic element includes a bottom plate, a cover plate, a first winding column, a second winding column, a third winding column, a primary winding, a first secondary winding, and a second secondary winding. The cover plate is arranged opposite to the bottom plate. The first winding column is arranged between the bottom plate and the cover plate. The second winding column is arranged between the bottom plate and the cover plate. The third winding column is arranged between the bottom plate and the cover plate. The primary winding is wound around the first winding column. The first secondary winding is wound around the second winding column. The second secondary winding is wound around the third winding column. The first winding column extends in a first direction and has a first length. The second winding column and the third winding column are arranged in the first direction and have a first distance. The first length is greater than the first distance.

[0006] Another embodiment of the present application provides a circuit board assembly. The circuit board assembly includes a circuit board, a magnetic component, a first switch set and a second switch set. The magnetic component includes a base plate, a cover plate, a first bobbin, a second bobbin, a third bobbin, a primary winding, a first secondary winding and a second secondary winding. The cover plate is disposed opposite to the base plate. The first bobbin is disposed between the base plate and the cover plate. The second bobbin is disposed between the base plate and the cover plate. The third bobbin is disposed between the base plate and the cover plate. The primary winding is wound around the first bobbin. The first secondary winding is wound around the second bobbin. The second secondary winding is wound around the third bobbin. The first bobbin extends along a first direction and has a first length. The second bobbin and the third bobbin are disposed along the first direction and have a first distance. The first length is greater than the first distance. The first switch set is disposed on the circuit board and coupled to the primary winding. The second switch set is disposed on the circuit board and coupled to the first secondary winding and the second secondary winding.

[0007] So that the foregoing and other objects, features and advantages of the present application can be readily understood, a more particular description of the application follows, as illustrated in the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1 An equivalent circuit diagram of a circuit board assembly according to an embodiment of the present application is shown;

[0009] Figure 2A A structural diagram of a magnetic component according to Figure 1 is shown;

[0010] Figure 2B A diagram showing Figure 1 a primary winding of Figure 2A disposed around a first bobbin of Figure 2A and secondary windings disposed around two second bobbins of

[0011] Figure 2C A top view of the magnetic component of Figure 2B is shown;

[0012] Figure 3 A diagram showing a leakage flux path of the magnetic component of Figure 2B is shown;

[0013] Figure 4 A diagram of a circuit board assembly according to an embodiment of the present application is shown;

[0014] Figure 5 A diagram of a circuit board assembly according to another embodiment of the present application is shown;

[0015] Figure 6 A diagram of a circuit board assembly according to another embodiment of the present application is shown;

[0016] Figure 7 a schematic diagram of a magnetic element according to another embodiment of the present application is shown;

[0017] Figure 8 an equivalent circuit diagram of a circuit board assembly according to another embodiment of the present application is shown.

[0018] wherein the reference signs refer to:

[0019] 10, 10', 10", 20: circuit board assembly;

[0020] 11: first switch group

[0021] 12, 22: second switch group;

[0022] 100, 200: magnetic element;

[0023] 110: base plate;

[0024] 120: cover plate;

[0025] 130: first winding post;

[0026] 130e, 140Ae, 140Be: connection surface;

[0027] 140A: second winding post;

[0028] 140B: third winding post;

[0029] 150, 250: primary winding;

[0030] 151: first primary sub-winding;

[0031] 152: second primary sub-winding;

[0032] 160A: first secondary winding;

[0033] 160B: second secondary winding;

[0034] 161: first secondary sub-winding;

[0035] 162: second secondary sub-winding;

[0036] 163: third secondary sub-winding;

[0037] 164: fourth secondary sub-winding;

[0038] 170: circuit board;

[0039] 170s1: first surface;

[0040] 170s2: second surface;

[0041] 171: heat dissipation region;

[0042] 170a1: first through-hole;

[0043] 170a2: second through-hole;

[0044] 170a3: third through-hole;

[0045] 240C: fourth bobbin;

[0046] 260C: third secondary winding;

[0047] 253: third primary sub-winding;

[0048] 265: fifth secondary sub-winding;

[0049] 266: sixth secondary sub-winding;

[0050] A 130e : first area;

[0051] A 140Ae : second area;

[0052] A 140Be : third area;

[0053] A’ 140e : area sum;

[0054] AX1, AX2, AX3: extension axis;

[0055] H1: first interval;

[0056] H2: second interval;

[0057] H3: third interval;

[0058] L 130 : first length;

[0059] L 110 : base plate length;

[0060] L m1 ,L m2 : excitation inductance;

[0061] R a1 ,R C ,R S ,R a1 ,R a2 : reluctance;

[0062] S1: first switch;

[0063] S2: second switch;

[0064] S3: third switch;

[0065] S4: fourth switch;

[0066] SR1, SR2, SR3, SR4, SR5, SR6: rectifier switch;

[0067] V in : input voltage;

[0068] V out : output terminal;

[0069] X: first direction;

[0070] Y: second direction;

[0071] Z: third direction;

[0072] Φ i , Φ C , Φ S : magnetic flux;

[0073] Φ IK1 : first leakage flux;

[0074] Φ IK2 : second leakage flux. DETAILED DESCRIPTION

[0075] The following detailed description provides many different embodiments, or examples, for implementing different features of the provided application. The following detailed description is not intended to limit the scope of the various embodiments and / or components as described and / or claimed herein. Rather, the following detailed description is intended to describe the various embodiments and / or components in sufficient detail to enable one skilled in the art to practice the various embodiments and / or components.

[0076] As to the terms 'first','second', etc. used herein, they are not intended to refer to order or sequence, but to distinguish different elements or operations described in the same technical terms.

[0077] Reference is made to Figure 1 , Figures 2A-2C , Figure 3 and Figure 4 , Figure 1 a schematic equivalent circuit diagram of a resonant converter 10 according to an embodiment of the present application, Figure 2A a schematic structural diagram of a magnetic element 100 according to Figure 1 , Figure 2B a schematic diagram showing that a primary winding 150 according to Figure 1 is arranged at a first bobbin 130 according to Figure 2A , and a first secondary winding 160A and a second secondary winding 160B are arranged at a second bobbin 140A and a third bobbin 140B, respectively, according to Figure 2A ,Figure 2C a top view of the magnetic element 100 (omitting the cover plate 120), Figure 2B a schematic diagram of a leakage flux path of the magnetic element 100, and Figure 3 a schematic diagram of a circuit board assembly 10 according to an embodiment of the present application. Figure 2B a top view of the magnetic element 100 (omitting the cover plate 120), Figure 4 a schematic diagram of a leakage flux path of the magnetic element 100, and

[0078] As shown in Figure 1 and Figure 4 , in the present embodiment, the circuit board assembly 10 includes, for example, an LLC series resonant converter, but embodiments of the present application are not limited thereto. The circuit board assembly 10 includes at least a circuit board 170 (shown in Figure 4 ), at least one magnetic element 100, a first switch group 11, and a second switch group 12.

[0079] As shown in Figure 2A , 2B and Figure 4 , the magnetic element 100 includes at least a base plate 110, a cover plate 120, a first winding post 130, a second winding post 140A, a third winding post 140B, a primary winding 150, a first secondary winding 160A, a second secondary winding 160B, a circuit board 170 (shown in Figure 4 ), and a semiconductor chip 180 (shown in Figure 4 ). The cover plate 120 is disposed opposite the base plate 110. The first winding post 130, the second winding post 140A, and the third winding post 140B can be disposed between the base plate 110 and the cover plate 120. The primary winding 150 is wound around the first winding post 130. The first secondary winding 160A and the second secondary winding 160B are wound around the second winding post 140A and the third winding post 140B, respectively. Since the primary winding 150 is wound around the first winding post 130, the leakage inductance can be increased, so that an additional inductor (which results in a larger footprint and a larger copper loss) does not need to be disposed, thereby increasing the space utilization and reducing the overall energy loss (e.g., the sum of the copper loss and the iron loss / core loss). The units of “copper loss” and “iron loss” herein are, for example, Watts (W).

[0080] As shown in Figure 2C , in an embodiment, the first winding post 130 extends along a first direction X and has a first length L 130 , and the second winding post 140A and the third winding post 140B are disposed along the first direction X and have a first spacing H1 (e.g., the shortest spacing), wherein the first length L 130 is greater than the first spacing H1.

[0081] As shown in Figure 1and Figure 4 As shown, the first switch group 11 is disposed on the circuit board 170 and coupled to the primary winding 150. The first switch group 11 includes several switches, such as a first switch S1, a second switch S2, a third switch S3, and a fourth switch S4. The first switch S1, the second switch S2, the third switch S3, and the fourth switch S4 are electrically connected to the input terminal V. in The primary winding 150 of the magnetic element 100 is connected to the secondary winding 160A and the secondary winding 160B. A second switch group 12 is disposed on the circuit board 170 and coupled to both the primary winding 160A and the secondary winding 160B, and includes at least rectifier switches SR1, SR2, SR3, and SR4. Rectifier switches SR1, SR2, SR3, and SR4 connect the secondary windings (160A and 160B) of the magnetic element 100 to the output terminal V. out Furthermore, the first switch group 11 is disposed on the first side of the magnetic element 100, and the second switch group 12 is disposed on the second side of the magnetic element 100, wherein the first side and the second side are adjacent sides of the magnetic element 100.

[0082] In the embodiment, the base plate 110, cover plate 120, first winding post 130, second winding post 140A and third winding post 140B are, for example, iron cores.

[0083] In a comparative example, compared to magnetic elements with an additional inductor, the footprint (in terms of the iron core) of the magnetic element in the embodiment of the present invention (which does not require an additional inductor) can be reduced by, for example, by about 30%, copper losses by, for example, by about 16.3% (because no additional inductor is required), while iron losses increase by about 5.6%. It is worth noting that although iron losses increase, the total losses are still reduced by 9.1%.

[0084] like Figure 3 As shown, the magnetic reluctance R i This indicates the magnetic reluctance of cover plate 120, and the magnetic flux Φ. i This represents the magnetic flux through the cross-section of cover plate 120. Magnetic reluctance R C This indicates the magnetic reluctance of the second winding post 140A or the third winding post 140B, and the magnetic flux Φ. C This represents the magnetic flux passing through the cross section of the second winding post 140A or the third winding post 140B. Magnetic reluctance R S This represents the magnetic reluctance of the first winding post 130, with magnetic flux Φ. S This represents the magnetic flux passing through the cross-section of the first winding post 130. Magnetic reluctance R a1 The air reluctance is on the secondary winding side, and the reluctance R... a2 The air reluctance is on the primary winding side. The first leakage flux Φ IK1 Not with secondary windings 160A and 160B (not shown) Figure 3 The coupling occurs, but the magnetic flux path passes through the first winding post 130, causing additional iron loss. The second leakage flux Φ IK2The magnetic flux path is surrounded by either the primary winding 160A or the secondary winding 160B (not shown in the diagram). Figure 3 The static current of the winding is 0 amperes and it is not coupled to the secondary winding (160A or 160B), but it flows through the first winding post 130, the base plate 110, and the cover plate 120, thus causing additional iron losses. Furthermore, through magnetoresistance analysis, the first leakage flux Φ IK1 and the second leakage flux Φ IK2 The increase is significant, resulting in a significant increase in leakage inductance.

[0085] In a comparative example, the primary winding 150 is wound on the second winding post 140A and the third winding post 140B (i.e., not wound on the first winding post 130), generating a leakage inductance of approximately 8.79 nanohenries (nH). Compared to this comparative example, the primary winding 150 of this embodiment is wound on the first winding post 130, generating a leakage inductance of approximately 454 nanohenries. Compared to the comparative example, the leakage inductance of the magnetic element 100 of this embodiment is increased by at least 51 times. Furthermore, in the comparative example, the primary winding 150 is wound on the second winding post (not wound on the first winding post 130), generating approximately 15.16 W of copper loss and 8.21 W of iron loss. Compared to this comparative example, the primary winding 150 of this embodiment is wound on the first winding post 130, generating approximately 17.23 W of copper loss and 10.75 W of iron loss.

[0086] like Figure 2A As shown, the projection of the first winding post 130 along the second direction Y at least partially overlaps with the second winding post 140A and the third winding post 140B. Specifically, the projection areas of the second winding post 140A and / or the third winding post 140B along the second direction Y onto the first winding post 130 at least partially overlap with the first winding post 130. The aforementioned second direction Y is different from the first direction X; for example, the second direction Y is substantially perpendicular to the first direction X.

[0087] like Figure 2A As shown, the first winding post 130 extends in a different direction than the second winding post 140A and / or the third winding post 140B. For example, the extension axis (or major axis) AX1 of the first winding post 130 extends along a first direction X, while the extension axis (or central axis) AX2 of the second winding post 140A and / or the extension axis (or central axis) AX3 of the third winding post 140B extends along a third direction Z, wherein the third direction Z is different from the first direction X; for example, the first direction X and the third direction Z are perpendicular to each other. Specifically, the first winding post 130 is, for example, a polyhedral prism (e.g., a triangular prism, a square prism, etc.), while the second winding post 140A and / or the third winding post 140B are, for example, cylindrical or elliptical cylinders. However, the embodiments of the present invention do not limit the cross-sectional shape of the winding posts.

[0088] like Figure 2BAs shown, in this embodiment, the second winding post 140A and the third winding post 140B can be configured separately along the first direction X. The first stage winding 160A and the second stage winding 160B are respectively wound on the second winding post 140A and the third winding post 140B. In another embodiment, the magnetic element 100 may omit the third winding post 140B.

[0089] like Figure 2B The primary winding 150 and secondary windings (160A and 160B) shown are for illustrative purposes only. Figure 2B I P This indicates the direction of current in the primary winding 150, while I S This indicates the direction of current in the secondary winding 160. The diagram shows the current direction as I. P This indicates the winding direction or method of the primary winding 150, while the current direction I is used to indicate the winding direction or method. S The winding direction or method of the secondary winding is indicated. In this embodiment of the invention, the specific winding method of the primary winding 150 and the secondary windings (160A and 160B) is not limited.

[0090] like Figure 2A and Figure 2C As shown, the connection surface (e.g., contact surface) between the first winding post 130 and the cover plate 120 has a first area, the connection surface (e.g., contact surface) between the second winding post 140A and the cover plate 120 has a second area, and the connection surface (e.g., contact surface) between the third winding post 140A and the cover plate 120 has a third area, wherein the ratio of the first area to the sum of the second and third areas can be between 80% and 150%. For example, the connection surface 130e between the first winding post 130 and the cover plate 120 has a first area A. 130e The connection surface 140Ae between the second winding post 140A and the cover plate 120 has a second area A. 140Ae The connection surface 140Be between the third winding post 140B and the cover plate 120 has a third area A. 140Be The second area A 140Ae With the third area A 140Be The sum of these is an area sum A' 140e The first area A 130e With area and A' 140e The proportion (i.e., A) 130e / A' 140e For example, it can be between 80% and 150%, such as 80%, 90%, 100%, 110%, 120%, 130%, 140% or 150%, but it can also be higher or lower.

[0091] like Figure 2C As shown, the ratio of the second area to the third area can be between 80% and 120%. For example, the second area A of the connecting surface 140Ae...140Ae The third area A of the connecting surface 140Be 140Be They can be the same or different. In one embodiment, the second area A 140Ae With the third area A 140Be One and the second area A 140Ae With the third area A 140Be The proportion of the other can be between 80% and 120%, for example, 80%, 90%, 100%, 110% or 120%, but it can also be higher or lower.

[0092] like Figure 2C As shown, in one embodiment, the base plate 110 has a base plate length L along the first direction X. 110 First length L 130 With the length L of the base plate 110 The ratio is, for example, between 50% and 100%, such as 50%, 60%, 70%, 80%, 90%, or 100%, but it can also be higher or lower. In other embodiments, the first winding post 130 and the second winding post 140A have a second spacing H2 (e.g., the shortest spacing) along the second direction Y, and the first winding post 130 and the third winding post 140B have a third spacing H3 (e.g., the shortest spacing) along the second direction Y. The ratio of the sum of the second spacing H2 and the third spacing H3 to the first spacing H1 is, for example, between 80% and 120%, such as 80%, 90%, 100%, 110%, or 120%, but it can also be higher or lower.

[0093] like Figure 4 As shown, the circuit board 170 has at least one heat dissipation area 171, which is made of metal, such as a metal pad. The area of ​​the heat dissipation area 171 may be smaller than the area of ​​the cover plate 120. For example, the heat dissipation area 171 is exposed from a first surface 170s1 of the circuit board 170, and the area of ​​the heat dissipation area 171 may be smaller than the projected area of ​​the cover plate 120 onto the first surface 170s1. In one embodiment, the area of ​​each heat dissipation area 171 is smaller than the area of ​​the cover plate 120. In another embodiment, the total area of ​​the plurality of heat dissipation areas 171 may be smaller than or larger than the area of ​​the cover plate 120. The configuration location, number, and / or area of ​​the heat dissipation areas 171 may depend on the configuration of electronic components (e.g., magnetic components 100, switch groups, chips, resistors, etc.) and the required heat dissipation efficiency, and are not limited in this embodiment of the invention.

[0094] The following is an introduction Figure 2B Winding design and Figure 1 The relationship between circuit design and circuit design.

[0095] like Figure 2B and Figure 1As shown, the primary winding 150 includes at least one primary sub-winding, such as a first primary sub-winding 151 and a second primary sub-winding 152. The secondary winding includes at least one primary sub-winding. For example, the first primary winding 160A includes a first primary sub-winding 161 and a second primary sub-winding 162, while the second primary winding 160B includes a third primary sub-winding 163 and a fourth secondary sub-winding 164. In an embodiment, the first primary sub-winding 161 is, for example, a first secondary-side positive half-cycle sub-winding, the second primary sub-winding 162 is, for example, a first secondary-side negative half-cycle sub-winding, the third primary sub-winding 163 is, for example, a second secondary-side positive half-cycle sub-winding, and the fourth secondary sub-winding 164 is, for example, a second secondary-side negative half-cycle sub-winding. The first primary sub-winding 151 and the second primary sub-winding 152 are connected in series and electrically connected to the switching circuit 11. The first stage sub-winding 161 and the third stage sub-winding 163 are connected in parallel and electrically connected to the rectifier circuit 12. The first stage sub-winding 161 and the second stage sub-winding 162 are electrically connected and form a first center tap structure. The third stage sub-winding 163 and the fourth stage sub-winding 164 are electrically connected and form a second center tap structure.

[0096] like Figure 2B and Figure 1 As shown, rectifier switch SR2 connects the primary winding 161 to the output terminal V. out The rectifier switch SR1 connects the secondary winding 162 to the output terminal V. out It is connected in reverse parallel with rectifier switch SR2. Rectifier switch SR4 connects the third stage sub-winding 163 to the output terminal V. out Furthermore, rectifier switch SR3 is connected to the fourth secondary winding 164 and the output terminal V. out It is connected in reverse parallel with the rectifier switch SR4. In this way, the magnetic element 100 forms two center-tapped rectifier circuits.

[0097] like Figure 1 As shown, when the first switch S1 and the fourth switch S4 are turned on, the second switch S2 and the third switch S3 are turned off, allowing the input current to flow through the first primary sub-winding 151 and the second primary sub-winding 152. Simultaneously, the rectifier switches SR2 and SR4 are turned on, allowing the induced current to flow simultaneously through the first primary sub-winding 161 and the third primary sub-winding 163. At this time, the induced current flowing through the first primary sub-winding 161 and the third primary sub-winding 163 has a current conduction direction opposite to that of the input current flowing through the first primary sub-winding 151 and the second primary sub-winding 152.

[0098] When the second switch S2 and the third switch S3 are turned on, the first switch S1 and the fourth switch S4 are turned off, allowing the input current to flow through the first primary sub-winding 151 and the second primary sub-winding 152. Simultaneously, the rectifier switches SR1 and SR3 are turned on, allowing the induced current to flow through the second secondary sub-winding 162 and the fourth secondary sub-winding 164. At this time, the induced current flowing through the second secondary sub-winding 162 and the fourth secondary sub-winding 164 has a current conduction direction opposite to that of the input current flowing through the first primary sub-winding 151 and the second primary sub-winding 152.

[0099] like Figure 4 As shown, the magnetic element 100, including the circuit board 170, can also be referred to as a planar magnetic element. In another embodiment, the circuit board 170 and the magnetic element 100 can be sub-elements of the same order in the circuit board assembly 10. The circuit board 170 can be disposed between the cover plate 120 and the base plate 110. Although not shown, the circuit board 170 may have a first through hole 170a1, a second through hole 170a2, and a third through hole 170a3, wherein the first through hole 170a1 allows the primary winding 150 to pass through, the second through hole 170a2 allows the primary winding 160A to pass through, and the third through hole 170a3 allows the secondary winding 160B to pass through. The circuit board 170 is, for example, a printed circuit board (PCB).

[0100] Although not shown, however Figure 2B The primary winding 150 and the secondary windings (160A and 160B) can be configured in the circuit board 170. For example, the circuit board 170 can be a multilayer circuit board, which may contain multiple circuit layers along the thickness direction. Adjacent circuit layers can be electrically connected by conductive vias (not shown). The primary winding 150 may be located in at least one layer of the circuit board 170, and the secondary windings (160A and 160B) may be located in at least one layer of the circuit board 170. The primary winding 150 and the secondary windings (160A and 160B) may be located in different circuit layers in the circuit board 170.

[0101] Although not shown, the primary winding 150 and / or the secondary winding 160 located in the circuit board 170 may be electrically connected to rectifier switches SR1, SR2, SR3 and SR4 and the first switch S1, the second switch S2, the third switch S3 and the fourth switch S4 through at least one conductive hole and / or at least one wiring (e.g., disposed on the line layer of the circuit board 170).

[0102] Please refer to Figure 5Fig. 6 shows a schematic diagram of a circuit board assembly 10' according to another embodiment of the present application. The circuit board assembly 10' comprises at least a circuit board 170, at least one magnetic element 100, a first switch set 11 and a second switch set 12. The circuit board assembly 10' comprises the same or similar technical features as the circuit board assembly 10 described above, except that the first switch set 11 and the second switch set 12 are respectively arranged on opposite sides of the magnetic element 100.

[0103] Referring to Fig. 6, Figure 6 Fig. 6 shows a schematic diagram of a circuit board assembly 10' according to another embodiment of the present application. The circuit board assembly 10' comprises at least a circuit board 170, at least one magnetic element 100, a first switch set 11 and a second switch set 12. The circuit board assembly 10' comprises the same or similar technical features as the circuit board assembly 10 described above, except that the first switch set 11 and the second switch set 12 are respectively arranged on opposite sides of the magnetic element 100.

[0104] Referring to Fig. 6, Figure 7 and Figure 8 , Figure 7 Fig. 6 shows a schematic diagram of a circuit board assembly 10' according to another embodiment of the present application. The circuit board assembly 10' comprises at least a circuit board 170, at least one magnetic element 100, a first switch set 11 and a second switch set 12. The circuit board assembly 10' comprises the same or similar technical features as the circuit board assembly 10 described above, except that the first switch set 11 and the second switch set 12 are respectively arranged on opposite sides of the magnetic element 100. Figure 8 Fig. 6 shows a schematic diagram of a circuit board assembly 10' according to another embodiment of the present application. The circuit board assembly 10' comprises at least a circuit board 170, at least one magnetic element 100, a first switch set 11 and a second switch set 12. The circuit board assembly 10' comprises the same or similar technical features as the circuit board assembly 10 described above, except that the first switch set 11 and the second switch set 12 are respectively arranged on opposite sides of the magnetic element 100.

[0105] As Figure 7As shown, the magnetic component 200 includes at least a base plate 110, a cover plate 120, a first winding post 230, a second winding post 140A, a third winding post 140B, a fourth winding post 240C, a primary winding 250 (not shown), at least one primary winding (e.g., a first primary winding 160A, a second primary winding 160B, and a third primary winding 260C), a circuit board (not shown), and a semiconductor chip (not shown). The cover plate 120 is configured opposite to the base plate 110. The first winding post 230 is disposed between the base plate 110 and the cover plate 120. The second winding post 140A, the third winding post 140B, and the fourth winding post 240C may be disposed between the base plate 110 and the cover plate 120. The primary winding 250 is wound around the first winding post 230. The primary winding 160A, the secondary winding 160B, and the tertiary winding 260C are wound on the second winding post 140A, the third winding post 140B, and the fourth winding post 240C, respectively. Since the primary winding 250 is wound on the first winding post 230, the leakage inductance can be increased, so there is no need to configure an additional inductor (this additional inductor would result in a larger footprint and increased copper losses), thereby increasing space utilization and reducing overall energy loss (e.g., the sum of copper losses and iron losses).

[0106] like Figure 8 As shown, the circuit board assembly 20 may include, for example, an LLC series circuit board, but embodiments of the present invention are not limited thereto. The circuit board assembly 20 includes at least a circuit board 170 (shown in...). Figure 4 ( ), at least one magnetic element 200, a first switch group 11 and a second switch group 22.

[0107] like Figure 8 As shown, the first switch group 11 is disposed on the circuit board 170 (circuit board 170 is shown in the figure). Figure 4 It is coupled to the primary winding 150. The first switch group 11 includes several switches, such as the first switch S1, the second switch S2, the third switch S3, and the fourth switch S4. The first switch S1, the second switch S2, the third switch S3, and the fourth switch S4 are electrically connected to the input terminal V. in The primary winding 150 of the magnetic element 100. The second switch group 22 is disposed on the circuit board 170 (circuit board 170 is shown in the figure). Figure 4 This is coupled to the primary winding 160A, the secondary winding 160B, and the tertiary winding 260C, and includes at least rectifier switches SR1, SR2, SR3, SR4, SR5, and SR6. Rectifier switches SR1, SR2, SR3, SR4, SR5, and SR6 connect the secondary windings (160A, 160B, and 260C) of the magnetic element 200 to the output terminal V. outFurthermore, the first switch group 11 is disposed on the first side of the magnetic element 200, and the second switch group 22 is disposed on the second side of the magnetic element 200, with the first side and the second side being adjacent or opposite sides of the magnetic element 200.

[0108] like Figure 8 As shown, the primary winding 250 includes a first primary sub-winding 151, a second primary sub-winding 152, and a third primary sub-winding 253. The secondary winding includes at least one primary sub-winding. For example, the first primary winding 160A includes a first primary sub-winding 161 and a second primary sub-winding 162, the second primary winding 160B includes a third primary sub-winding 163 and a fourth secondary sub-winding 164, and the third primary winding 260C includes a fifth secondary sub-winding 265 and a sixth secondary sub-winding 266. In this embodiment, the first primary sub-winding 161 is, for example, a first-secondary positive half-cycle sub-winding; the second primary sub-winding 162 is, for example, a first-secondary negative half-cycle sub-winding; the third primary sub-winding 163 is, for example, a second-secondary positive half-cycle sub-winding; the fourth primary sub-winding 164 is, for example, a second-secondary negative half-cycle sub-winding; the fifth primary sub-winding 265 is, for example, a third-secondary positive half-cycle sub-winding; and the sixth primary sub-winding 266 is, for example, a third-secondary negative half-cycle sub-winding. The first primary sub-winding 151, the second primary sub-winding 152, and the third primary sub-winding 253 are connected in series and electrically connected to the switching circuit 11. The first primary sub-winding 161 and the third primary sub-winding 163 are connected in parallel and electrically connected to the rectifier circuit 22. The third primary sub-winding 163 and the fifth primary sub-winding 265 are connected in parallel and electrically connected to the rectifier circuit 22. The first-stage sub-winding 161 and the second-stage sub-winding 162 are electrically connected to form a first center tap structure, the third-stage sub-winding 163 and the fourth-stage sub-winding 164 are electrically connected to form a second center tap structure, and the fifth-stage sub-winding 265 and the sixth-stage sub-winding 266 are electrically connected to form a third center tap structure.

[0109] like Figure 8 As shown, rectifier switch SR2 connects the primary winding 161 to the output terminal V. out The rectifier switch SR1 connects the secondary winding 162 to the output terminal V. out It is connected in reverse parallel with rectifier switch SR2. Rectifier switch SR4 connects the third stage sub-winding 163 to the output terminal V. out Furthermore, rectifier switch SR3 is connected to the fourth secondary winding 164 and the output terminal V. out It is connected in reverse parallel with rectifier switch SR4. Rectifier switch SR5 connects the sixth secondary winding 266 to the output terminal V. out It is connected in reverse parallel with the rectifier switch SR6.

[0110] In summary, the embodiments of the present application provide a magnetic element and a circuit board assembly using the same. The magnetic element is, for example, a transformer. The magnetic element can include a plurality of winding posts, a primary winding, and a secondary winding. Since the primary winding and the secondary winding are wound around different winding posts, leakage inductance can be increased, so that an additional inductor is not needed, thereby increasing space utilization and reducing overall energy loss. In one embodiment, a first winding post has a first area of a connection surface with the cover plate, a second winding post has a second area of a connection surface with the cover plate, and a third winding post has a third area of a connection surface with the cover plate. The ratio of the first area to the sum of the second area and the third area can be between 80% and 150%, but can be higher or lower. In another embodiment, the ratio of the second area to the third area can be between 80% and 120%, but can be higher or lower. In another embodiment, the first winding post has a first length in a direction, the bottom plate has a bottom plate length in the direction, and the ratio of the first length to the bottom plate length can be between 50% and 100%, but can be higher or lower. In another embodiment, the second winding post and the third winding post are separated by a first distance, and the second winding post and the third winding post are separated from the first winding post by a second distance and a third distance, respectively. The ratio of the sum of the second distance and the third distance to the first distance can be between 80% and 120%.

[0111] The above summary provides different features used in some embodiments or examples of the present application. The specific examples of components and configurations described above (e.g., the numerical values or names mentioned) are to simplify / suggest some embodiments of the present application. Of course, such components and configurations are only examples and are not intended to be limiting. In addition, some embodiments of the present application can repeatedly refer to reference signs and / or letters in various examples. This repetition is for the purpose of simplicity and clarity, and does not in itself indicate a relationship between the various embodiments and / or configurations discussed.

[0112] Although the present application has been disclosed in the above embodiments, it is not intended to limit the present application, and those skilled in the art can make some changes and modifications without departing from the spirit and scope of the present application. Therefore, the scope of protection of the present application is defined by the appended claims.

Claims

1. A magnetic element, characterized by, The magnetic element comprises: a bottom plate; a cover plate disposed opposite to the bottom plate; a first winding column disposed between the bottom plate and the cover plate; a second winding column disposed between the bottom plate and the cover plate; a third winding column disposed between the bottom plate and the cover plate; a primary winding wound on the first winding column; a first secondary winding wound on the second winding column; and a second secondary winding wound on the third winding column, wherein the first winding column extends along a first direction and has a first length, the second winding column and the third winding column are disposed along the first direction and have a first interval, and the first length is greater than the first interval.

2. The magnetic element of claim 1, wherein, A projection of the first winding column along a second direction at least partially overlaps the second winding column and the third winding column.

3. The magnetic element of claim 1, wherein, A connecting surface of the first winding column and the cover plate has a first area, a connecting surface of the second winding column and the cover plate has a second area, a connecting surface of the third winding column and the cover plate has a third area, and a ratio of the first area to a sum of the second area and the third area is between 80% and 150%.

4. The magnetic element of claim 1, wherein, A connecting surface of the second winding column and the cover plate has a second area, a connecting surface of the third winding column and the cover plate has a third area, and a ratio of the second area to the third area is between 80% and 120%.

5. The magnetic element of claim 1, wherein, The bottom plate has a bottom plate length along the first direction, and a ratio of the first length to the bottom plate length is between 50% and 100%.

6. The magnetic element of claim 1, wherein, The first winding column and the second winding column have a second interval along a second direction, the first winding column and the third winding column have a third interval along the second direction, and a ratio of a sum of the second interval and the third interval to the first interval is between 80% and 120%.

7. The magnetic element of claim 1, wherein, The magnetic element further comprises: a circuit board disposed between the cover plate and the bottom plate, wherein the primary winding, the first secondary winding, and the second secondary winding are disposed in the circuit board.

8. The magnetic element of claim 1, wherein, The magnetic element further comprises: a first leakage magnetic flux having a magnetic flux path passing through the first winding column; and a second leakage magnetic flux having a magnetic flux path passing through the first winding column, the bottom plate, and the cover plate, wherein the first leakage magnetic flux and the second leakage magnetic flux are not coupled to the first secondary winding and the second secondary winding.

9. The magnetic element of claim 8, wherein, The magnetic flux path of the second leakage magnetic flux has a static current of 0 ampere around the first secondary winding or the second secondary winding.

10. A circuit board assembly characterized by, The magnetic element comprises: a circuit board; a magnetic element disposed on the circuit board and having a bottom plate, a cover plate, a first winding column, a second winding column, a third winding column, a primary winding, a first secondary winding, and a second secondary winding, wherein the cover plate is disposed opposite to the bottom plate, the first winding column, the second winding column, and the third winding column are disposed between the bottom plate and the cover plate, the primary winding is wound on the first winding column, the first secondary winding is wound on the second winding column, the second secondary winding is wound on the third winding column, the first winding column extends along a first direction and has a first length, the second winding column and the third winding column are disposed along the first direction and have a first interval, and the first length is greater than the first interval; a first switch group disposed on the circuit board and coupled to the primary winding; and A second switch group is disposed on the circuit board and coupled to the first secondary winding and the second secondary winding.

11. The circuit board assembly of claim 10, wherein, The first winding post has a projection in a second direction that at least partially overlaps the second winding post and the third winding post, the second direction being perpendicular to the first direction.

12. The circuit board assembly of claim 10, wherein, The first switch group and the second switch group are disposed on opposite sides of the magnetic element.

13. The circuit board assembly of claim 10, wherein, The first switch group is disposed on a first surface of the circuit board, and the second switch group is disposed on a second surface of the circuit board, the first surface and the second surface being opposite surfaces of the circuit board.

14. The circuit board assembly of claim 13, wherein, The projection of the first switch group in a direction perpendicular to the second surface does not overlap the second switch group.

15. The circuit board assembly of claim 10, wherein, The circuit board has a heat dissipation region, the heat dissipation region being made of metal, and the area of the heat dissipation region being less than the area of the cover plate.

16. The circuit board assembly of claim 10, wherein, The circuit board has a plurality of heat dissipation regions, the heat dissipation regions being made of metal, and the total area of the heat dissipation regions being greater than the area of the cover plate.

17. The circuit board assembly of claim 10, wherein, The first switch group and the second switch group are disposed on opposite sides of the magnetic element.

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