Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F17/00—Fixed inductances of the signal type 
  • H01F17/04—Fixed inductances of the signal type  with magnetic core
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F17/00—Fixed inductances of the signal type 
  • H01F17/0006—Printed inductances

Definitions

• the present invention relates to a coil structure suitable for use in a transformer coil used in an electronic device or a power supply device, and more particularly to a device having good magnetic coupling, low loss, and good high-frequency characteristics when used as a transformer.
• Transformers are magnetic components used in electronic equipment and power supply devices. They provide insulation between the primary side and the secondary side, and the voltage on the secondary side is determined by the primary side voltage and the turns ratio. Having. Wire-wound transformers in which a conductor is wound around a bobbin are widely used as transformers for switching power supplies. In particular, the dimensions of the core, which is a magnetic core, are standardized by standards such as JIS and IEC.
• a transformer that does not use a bobbin for example, a printed coil type transformer in which windings are arranged on a single multilayer printed circuit board, which is disclosed in Japanese Patent Application Laid-Open No. 63-173,083, is known. ing. According to such a configuration, since the windings are arranged very close to each other, the loss through the leakage inductance is reduced. However, the present inventor has made further detailed investigations and found that the contribution of losses other than leakage inductance is large, so that a further reduction in loss is required.
• An object of the present invention is to solve such a problem, and an object of the present invention is to provide a small-sized printed coil type transformer having a rectangular shape in which transformer loss is minimized. Disclosure of the invention
• the present invention provides a coil laminated body 40 in which a plurality of concentric spiral coils are laminated in the thickness direction by using an insulating resin. Place 3 and 3 to set the magnetic coupling between the coils.
• the cross-sectional area of the core is made uniform along the magnetic path and the magnetic flux density is kept almost constant, the loss does not locally increase.
• the coil section is surrounded by the window formed by the core's midfoot and the leg core, the coil resistance can be minimized by optimizing the shape of the coil, and the transformer can be reduced in size.
• FIG. 1 is a perspective view showing a configuration of an assembled state showing one embodiment of the present invention, and is partially cut away.
• FIG. 2 is a cross-sectional view of the coil laminate 40.
• FIG. 3 is a diagram illustrating the details of the shape of the core 30.
• FIG. 4 is a conceptual diagram illustrating the relationship between the transformer loss P L oss and the cross section A e.
• FIG. 5 is a configuration perspective view showing a second embodiment of the present invention.
• FIG. 6 is a configuration diagram illustrating the shape of the UU-shaped core.
• FIG. 7 is a reference in comparison between the embodiment of FIG. 8 and the embodiment of FIG. 9, and is a configuration diagram when the dimension ratio (h Zw) of the core window is 1.
• FIG. 8 is a configuration perspective view showing a third embodiment of the present invention.
• FIG. 9 is a configuration perspective view showing a fourth embodiment of the present invention.
• FIG. 10 is a configuration perspective view showing a fifth embodiment of the present invention.
• FIG. 11 is a diagram illustrating the shape of the EE-shaped core.
• FIG. 12 is a configuration perspective view showing a sixth embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION
• FIG. 1 is a perspective view showing a configuration of an assembled state showing one embodiment of the present invention, in which a part of a coil laminate is cut away.
• a coil laminated body 40 is formed by integrating a conventional bobbin and a conductive wire, and a specific detailed structure thereof is disclosed in, for example, Japanese Patent Application Laid-Open No. Hei 6-3103545 proposed by the present applicant. Is disclosed.
• a through hole 41 is formed, and the upper core 31 and the lower hole are formed.
• FIG. 3 is a cross-sectional view of the coil laminated body 40, and shows a cross section taken along line 2-2 in FIG.
• the secondary coil 45 has two layers in the middle, and the upper and lower layers are sandwiched between the primary coils 44.
• An internal connection terminal 4 3 a that connects the primary coil 44 in each of the upper and lower layers near the core hole 41, and an internal connection terminal that connects all the primary coil 44 and the secondary coil 45 4 3b is provided.
• terminals 42 are provided on both sides of the coil laminate 40, one of which is the primary coil 44 of the upper and lower layers—the secondary terminal 42a, and the other is the secondary terminal 42a.
• the number of turns of the coil is 3 turns for each layer of the primary coil 44 and 2 turns for each layer of the secondary coil 45. Since each layer of the coil is filled with insulating resin, the separation distance required for obtaining various safety standards is as thin as 0.6 mm, which enables further downsizing of the transformer.
• FIG. 3 is a view for explaining the details of the shape of the core 30.
• A is a front view of an assembled state of the upper end 31 and the lower end 32
• B is a plan view of the core
• C is a plan view of the core
• D The diameter of the metatarsal core 33
• D The diameter of the metatarsal core 33
• the length of the connecting core 35 is A, the distance between the inner side surfaces of the leg cores 34 is E, and the thickness of the leg cores 34 is b.
• the distance between the inner side surface of the leg core 34 and the opposing peripheral surface of the middle leg 33 is w. Therefore, the following relationship holds.
• the distance between the opposing inner surfaces of the contact section 35 is h.
• the thickness of the contact section 35 is t, but the following relationship holds.
• the cross-sectional area Ae33 is twice as large as the cross-sectional areas Ae35 and Ae34 of the other cores since two magnetic flux lines pass through the middle cross-section. Defining the cross-sectional area of the foot core 33 as Ae33, it is as follows.
• V e 2 Ve35-f 2 Ve34 + Ve33
• iron loss refers to the power consumed by the magnetic core due to the time-varying magnetizing force, and the hysteresis loss and the eddy current loss is there.
• Iron loss PFe is expressed by the following equation.
• PFe ClVeB 2 f sw '(7)
• CI is a constant determined by the shape and material of the coil
• B is the magnetic flux density
• isw is the switching frequency. If the magnetic flux density B and the switching frequency f sw are constant, the iron loss P Fe is proportional to the core volume V e.
• Copper loss refers to load loss, including I 2 R loss due to eddy current and load in windings, stray loss due to leakage current, and loss caused by circulating current in parallel windings.
• the copper loss PCu is expressed by the following equation.
• the copper loss PCu is inversely proportional to the square of the core cross-sectional area A e.
• FIG 4 is a conceptual diagram illustrating the relationship between transformer loss P loss and core cross-sectional area A e.
• C Transformer loss P loss is defined by the sum of coil iron loss PFe and copper loss PCu. As expressed by Eq. (7), iron loss PFe tends to increase with increasing core cross-sectional area A e. On the other hand, the copper loss PCu tends to decrease as the core cross-sectional area A e increases. Therefore, for the transformer loss P loss that can be expressed by the sum of the two, there exists an optimal co-cutting area A e that minimizes the loss.
• Equation (12) C5 / ⁇ (ED) 2 D 4 ⁇ (12) In order to minimize transformer loss, Equation (12) should be minimized. (12) is minimized when the following condition is satisfied.
• the core shape that minimizes the transformer loss is as follows from the expressions a) and a6).
• FIG. 5 is a perspective view showing the configuration of the second embodiment of the present invention, wherein (A) shows a state in which a UU core is mounted on a coil laminate, and (B) shows a coil laminate. It shows a simple substance.
• the U-shaped connector has a connecting portion core 37 and two leg portions 36 provided at both ends thereof.
• the two-hole coil laminate 50 has two holes 5 la and 51 b.
• the detailed structure is described in, for example, Japanese Patent Application Laid-Open No. No. 9 discloses this.
• the terminals 52 are provided in a row on both sides of the two-hole coil laminate 50 along the direction in which the ends of the coil body 50 are mounted.
• a UU-shaped core or a UI-shaped core is mounted on the two-hole coil laminate 50 to form a closed magnetic circuit.
• FIG. 6 is a block diagram illustrating the shape of the UU-shaped core.
• (B) is a plan view of the U-shaped core.
• FIG. 6 uses the same reference numerals as in FIG. 3, but has values unique to FIG.
• the diameter of the leg core 36 is represented by D.
• the length of the joint 37 is A, the thickness is t, the width is C, and the distance between the inner peripheral surfaces of the legs 36 is 2 w. Therefore, the following equation holds for the core volume V e and the core cross-sectional area A e.
• V e A e ⁇ 2 (h + w) + 2 D ⁇ (19)
• the coefficient k is in the following range according to the equation (6).
• FIG. 7 is a reference for the embodiment of Fig. 8 and Fig. 9 and shows the configuration when the dimensional ratio (h / w) of the window is 1;
• (B) is a cross-sectional view taken along the line BB of (A), showing a state after the apparatus of FIG. 1 is substantially assembled.
• FIG. 8 is a configuration diagram showing a third embodiment of the present invention, in which the dimensional ratio (h / w) of the window is 1/2, and FIG. (B) is a cross-sectional view taken along line BB of (A).
• the cross section of the coil laminate 40 can be flattened, and the conductor can be further flattened. Therefore, the AC resistance related to copper loss can be reduced by increasing the conductor surface area due to the skin effect, and the copper loss is reduced. Therefore, the substantial increase in transformer loss is less than 5%.
• FIG. 9 is a configuration diagram showing a fourth embodiment of the present invention, in which the dimensional ratio (hw) of the end window is 2, and FIG. 9 (A) shows a state in which the EE core is mounted on the foil laminate. Plan view of the
• (B) is a BB sectional view of (A).
• the cross section of the coil laminate 40 can be vertically long.
• the planar dimensions of the coil laminate 40 are reduced, and the transformer mounting area can be reduced.
• FIG. 9 and FIG. 7 when the transformer mounting area is made vertically long, it is only half that in the case of the same size. Therefore, it is suitable for applications that require a small transformer mounting area, such as fields where high-density mounting is required.
• the transformer shape that minimizes the transformer loss is expressed by (18), (27) ), (28) and (29), the coefficient k may be in the following range.
• the product of the present invention has a lower height H of the EE type, and a shorter length A by about 10%. Therefore, the core volume V e has been reduced by about 20%, and conversely, the core cross-sectional area A e has been increased by about 30%. If the core volume Ve is small, the amount of the magnetic material used can be small, so that it can be manufactured lightly and inexpensively.
• the dimension ratio of the core window is hZw1 ⁇ 2l.5 in the product of the present invention, while that of the conventional transformer is flat.
• the transformer loss the copper loss is reduced by 40% and the iron loss is also reduced by 18%, indicating that the performance as a transformer is improved.
• FIG. 10 is a perspective view showing the configuration of a fifth embodiment of the present invention, in which (A) shows a state in which the EE type is mounted on a coil laminate, and (B) shows a coil laminate alone.
• FIGS. 11A and 11B are configuration diagrams illustrating the shape of the EE-type core.
• FIG. 11A is a front view of an assembled state of the EE-type core
• FIG. 11B is a plan view of the E-type core.
• This embodiment 5 is a modification of the embodiment of FIG. 3.
• the diameter D of the middle foot 33 is equal to the width C of the connection 35, but here, D ⁇ C has been selected.
• the thickness b of the leg portion can be reduced, and the dimensions h and w of the core window can be increased, so that the area hw of the core window can be increased.
• the transformer can be further reduced in size and thickness.
• FIGS. 12 and 13 are perspective views showing the configuration of the sixth embodiment of the present invention.
• FIG. 12 (A) shows a state in which an EI type coil is mounted on a coil laminate
• FIG. 12 (B) shows a coil laminate alone
• FIG. Fig. 7 is an explanatory diagram of a state in which an EI type is assembled.
• This embodiment 6 is a modification of the embodiment of FIG. 3, and is different from the embodiment shown in FIG. Even in this case, the same effect as in the first embodiment can be obtained by making the core window shapes h and w substantially the same.
• the dimensional ratio (hw) of the core window is set in the range of 0.5 to 2

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Coils Or Transformers For Communication (AREA)
• Coils Of Transformers For General Uses (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=15436322

Family Applications (1)

Country Status (3)

Cited By (5)

Families Citing this family (4)

Citations (6)

Family Cites Families (5)

• 1995
  • 1995-06-14 TW TW84106066A patent/TW436823B/zh not_active IP Right Cessation
  • 1995-06-15 WO PCT/JP1995/001195 patent/WO1996000972A1/ja not_active Application Discontinuation
  • 1995-06-15 EP EP95921971A patent/EP0716435A4/de not_active Ceased

Patent Citations (6)

Non-Patent Citations (1)

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