WO2019033879A1

WO2019033879A1 - Transformer

Info

Publication number: WO2019033879A1
Application number: PCT/CN2018/095592
Authority: WO
Inventors: 郭启利; 李永昌
Original assignee: 广州金升阳科技有限公司
Priority date: 2017-08-17
Filing date: 2018-07-13
Publication date: 2019-02-21
Also published as: CN107424794A

Abstract

The present invention provides a transformer. The transformer comprises a pair of combined magnetic cores and a framework provided with four terminal blocks, and can be used in a power supply product provided with two or more PCBs and having a high requirement on a power density. The volume of the power supply product can be reduced, and the space utilization can be improved. The winding and the assembly of the transformer can be automatically carried out, and accordingly, the production efficiency can be improved.

Description

a transformer

Technical field

The invention relates to a transformer, in particular to a double-sided connected transformer, which is mainly used in a switching power supply and a module power supply.

Background technique

The transformer skeleton is a component of the main structure of the electronic transformer. Its main functions are: (1) to provide the winding space for the copper wire in the transformer; (2) to carry the core; (3) the wire slot in the skeleton provides the path of the wire when the transformer is wound; (4) the metal pin in the skeleton is the transformer copper wire Wrapped pillars; connected to the PCB after soldering, and function as an electrical connection when the transformer is working; (5) The baffle at the bottom of the skeleton can make the transformer and the PCB board have a fixed positioning effect; the tin stack generated during soldering Provides spacing from PCB boards, cores, and PCB boards.

With the continuous improvement and development of power products, the requirements for transformers are becoming more diverse. In the prior art, the transformer is generally electrically connected to the PCB by a single-sided connection, as shown in FIG. 1-1, which is a commonly used transformer in the prior art. The transformer 91 is mainly disposed on the circuit board 96, and is directly soldered to the circuit board by the

pins

92 and 93 of the primary side and the secondary side of the transformer 91, and is electrically connected to the circuit on the circuit board 96. In turn, it functions as a transformer.

However, such a transformer structure is generally suitable for use in a power supply product having only one PCB board. In power supply products that require high volume or power density, two or more PCB boards may be required. In this case, such a single-sided transformer cannot meet the requirements.

Figure 1-2 shows two PCB substrates in a switching power supply product and a transformer that connects two PCB substrates. The transformer of Figure 1-1 is replaced with a longer pin. The purpose of connecting the upper substrate and the lower substrate is achieved. However, such a transformer is connected to the two substrates, and the degree of automation is low, and only by manual soldering, the transformer cannot be soldered to the PCB substrate by reflow soldering or by reflow soldering. The welding method is soldered on the substrate. As the labor cost becomes higher and higher, the cost of producing the transformer and its switching power supply product will be higher and higher; and the solution does not utilize the upper space and space where the transformer core is located. Low utilization.

As shown in Figure 1-3, a common connection between two PCBs is shown. The solution is to connect the pins or terminals between the two PCBs to achieve electrical connection between the upper substrate and the lower substrate. The terminal occupies too much space and is not suitable for use in high power density products with small product sizes.

Chinese Patent Application No. 201420301769.2, entitled "Transformer Connecting Both Upper and Lower Sides", hereinafter referred to as Background Document 1, shows a transformer structure suitable for two substrates. For convenience, the background document of this application Figure 5 of Figure 1 is presented in this application, see Figures 1-4 of the present application. It can be seen that the transformer can be used by two PCB power boards at the same time, that is, two boards share one transformer, which enhances the coupling and effectively reduces the volume of the product. However, the transformer is still in the application of the actual high power density product. The following deficiencies exist:

(1) The winding of the transformer is wound on the top surface and the bottom surface of the skeleton, which determines that in the case where the original secondary side has high isolation requirements, at least one PCB of the transformer corresponding to the coil cannot be arranged with a trace or a via hole, otherwise it will cause The insulation voltage between the input and output of the switching power supply of the transformer is lowered, and the problem can be optimized by adding one or more layers of insulating adhesive paper to the outside of the coil, adding an insulating gasket, etc., but the transformer needs to be produced. It consumes more manpower and material costs, while increasing the size of the transformer.

(2) A clear surface of the transformer can only be used as the primary side or the secondary side of the transformer. It cannot have both the primary side and the secondary side on the same surface;

(3), can not directly connect the upper and lower sides of the transformer with a wire before the core is fixed. Only after the core is wrapped by the transformer, re-route the wire up and down again, and then re-wire the wire on the terminal. Go, can not achieve the machine winding, increase production costs.

(4) From the top or bottom, the winding space of the skeleton slot is larger in length and width, but the depth is smaller. In this structure, the transformer that is wound out has a large leakage inductance and is wound in the same number of turns. The length of the coil wire is longer, and the number of coils of the same wire diameter cannot be more. Otherwise, it is easy to wind the wire beyond the space of the wire slot and cause bad. It is suitable for low power transmission where the transformer loss is not high, and is not suitable for power comparison. Large and large transformers with large numbers and small volume; this problem can be optimized by increasing the size of the transformer slot, but the size of the corresponding transformer core and skeleton will become larger, and the volume of the product will also increase.

Summary of the invention

In view of this, the present invention is to solve the deficiencies of the existing double-sided transformer, and provides a double-sided connected transformer suitable for a power supply product having two or more PCB boards with high power density requirements.

In order to achieve the above object, the present invention is achieved by the following technical solution: a transformer comprising a pair of combined cores and a bobbin, characterized in that: the bobbin comprises a hollow winding portion, and the winding portion is used for winding Winding, the hollow portion of the winding portion is used to carry the center pillar of the combined core, and the pair of combined magnetic cores are fixed by at least one turn of the magnetic core tape having a certain insulation level; the winding portions are two The first baffle 21 and the second baffle 22 are disposed in a direction perpendicular to the central axis of the winding portion, and the first baffle 21 and the second baffle 22 are parallel for limiting the winding range of the winding; A first terminal block 211 and a second terminal block 212 are disposed at two ends of the first baffle 21, and a third terminal block 221 and a fourth terminal block 222 are disposed at two ends of the second baffle 22, the first The horizontal inner surface of the terminal block 211 and the second terminal block 212 are in the same plane as the inner surface of the first baffle 21, and the horizontal inner surface of the third terminal block 221 and the fourth terminal block 222 and the second baffle 22 The inner surfaces are in the same plane, on the horizontal outer surface of each terminal block There is a set of pins.

Preferably, the horizontal outer surfaces of the first terminal block 211 and the second terminal block 212 are higher than the outer surface of the first baffle 21, and the horizontal outer surfaces of the third terminal block 221 and the fourth terminal block 222 are higher than The outer surface of the second baffle 22.

Preferably, two or more pins on the first terminal block 211 are connected to two or more pins on the third terminal block 221 by one or more wires. Or two or more pins on the second terminal block 212 are connected to two or more pins on the fourth terminal block 222 by one or more wires.

Preferably, the pin is a pin pin.

Preferably, the pin pins are used to fix the winding head of the winding, and the transformer is electrically connected to the circuit board through the pin pins.

Preferably, the pair of combined magnetic cores are bundled together by a magnetic core tape having a certain insulation level, and the magnetic core tape surrounds at least one of the magnetic cores.

Preferably, the pin pin is a pin pin bent into an L shape, and a bending point of the L-shaped pin pin is buried inside the terminal block, and one end of the L-shaped pin pin extends out of the terminal block level The outer surface, the other end of the L-shaped pin extends out of the vertical outer surface of the terminal block.

Preferably, the pin is a chip pin, and the chip pin is disposed on a horizontal outer surface of the terminal block, and one end of the chip pin extends beyond a horizontal outer surface of the terminal block.

Preferably, the chip pins are used to fix the winding head of the winding, and the transformer is electrically connected to the circuit board through the chip pins.

Preferably, the chip pin is a semi-finished chip pin having two terminals, the two terminals of the half-shaped chip pin are parallel, and the part connecting the two terminals in the middle is buried inside the terminal block. One terminal of the semi-formed chip pin is horizontally disposed on the horizontal outer surface of the terminal block, and the terminal head does not extend beyond the horizontal outer surface of the terminal block; the other terminal of the semi-formed patch extends out of the vertical outer surface of the terminal block.

Preferably, any two sets of pins serve as primary pins of the transformer, and the other two sets of pins serve as secondary pins of the transformer.

Preferably, a pair of combined cores are held together by an insulated core tape that surrounds at least one of the cores.

Compared with the prior art, the beneficial effects of the present invention are:

(1) The corresponding PCB position on the upper and lower sides of the transformer can arrange PCB traces or vias to increase the PCB utilization rate, which can further reduce the product volume and increase the power density;

(2), the transformer 4 group terminals can be arbitrarily combined, two groups are the primary side, the remaining two groups are the secondary side, one group is the primary side, and the remaining three groups are the secondary side; vice versa;

(3) The upper and lower sides of the transformer can also be provided with more terminals, so that the signal traces between the upper and lower PCBs can be directly connected to the corresponding terminals on the upper and lower sides of the transformer by one or more wires, instead of the upper and lower two. The PCB must be connected through the external terminals of the terminal to further reduce the volume of the product and increase the power density;

(3) It can be used in power products with high power density requirements of two or more PCB boards, which can improve space utilization, reduce the volume of power products, and thus increase the power density of switching power supplies.

(4) The same number of transformer windings have short wire lengths, and the number of wires or strands can be more, the resistance of the corresponding coil is smaller, and the transformer loss is smaller;

(5) The transformer can realize automatic winding of the machine, including connecting the terminals through the upper and lower sides of the transformer;

(6) In addition to the above several advantages, the transformer of the present invention can be assembled on the PCB by reflow soldering, and the production efficiency is improved as compared with manual soldering.

DRAWINGS

1-1 is a structural diagram of a PCB connected to a transformer in the prior art;

1-2 is a structural diagram of a prior art transformer connecting two PCB boards;

Figure 1-3 is a schematic structural view of two PCB boards;

1-4 are schematic structural diagrams of a transformer connecting two PCB boards in the prior art;

Figure 2 is a perspective view of a transformer according to a first embodiment of the present invention;

Figure 3 is a split view of the first embodiment of the present invention;

Figure 4 is a perspective view of a transformer according to a second embodiment of the present invention;

Figure 5 is a perspective view of a transformer according to a third embodiment of the present invention;

Figure 6 is a perspective view of a transformer according to a fourth embodiment of the present invention.

Detailed ways

First embodiment

2 is a perspective view of the transformer of the present embodiment, and FIG. 3 is a schematic view of the assembly. A transformer comprising a core 11 and a core 12, and a skeleton. The core 11 and the core 12 are selected from an ER type core. The fixing is carried out by wrapping the magnetic core tape having a certain insulating strength at least one turn.

The choice of ER core has the following beneficial effects:

1. For the coil of the same circumference, the Ae value of the ER core is relatively large, which is beneficial to the miniaturization of the transformer;

2. The middle column of the ER core is round and the coupling position is good, which can reduce the leakage inductance and improve the efficiency;

The skeleton includes a hollow winding portion 20 which is vertically disposed, the winding portion 20 is used for winding winding, the hollow portion of the winding portion is used for placing the center pillar of the combined core, and the winding portion 20 is provided with two ends in the horizontal direction Baffles 21 and 22 for limiting the range of windings; 21 and 22 are respectively provided with a terminal block 211, a terminal block 212, a terminal block 221, and a terminal block 222; each terminal block is provided on the horizontal outer surface Pin pin 23, pin pin 23 is used to fix the bobbin, and the transformer is connected to the PCB through pin pin 23.

The windings are respectively wound on the winding portion 20, and the winding heads of the windings are respectively fixed on the pins of the four terminal blocks, and any two sets of pins serve as primary pins of the transformer, and the other two sets of pins serve as secondary leads of the transformer. The feet form the primary side and the secondary side of the transformer.

The core 11 and the core 12 pass through the hollow portions at both ends of the winding portion, respectively, and are assembled with the winding portion.

Second embodiment

Different from the first embodiment, the pin pin is a pin pin bent into an L shape, and the bent point of the pin pin is buried inside the terminal block, and one end of the L-shaped pin extends out of the terminal. A horizontal outer surface for connecting the transformer to the PCB; the other end of the L-shaped pin extends out of the vertical outer surface of the terminal block for securing the winding head. As shown in pin 4 in Figure 4. The horizontal outer surface and the vertical outer surface of the terminal block can be connected to the PCB board. The product volume can be further reduced.

Third embodiment

Different from the first embodiment, the pin pins are replaced with patch pins, and the horizontal outer surface of each terminal block is provided with a chip pin 25, and one end of the chip pin 25 extends beyond the horizontal outer surface of the terminal block. As shown in Figure 5. Pin 25 is used to fix the winding of the winding and is fixed to the PCB by reflow soldering for connecting the transformer to the PCB.

Fourth embodiment

Unlike the third embodiment, the chip pins are half-shaped chip pins having two terminals. Since the pin is shaped like a half "work", it is named a half-shaped patch pin in this application. The two terminals of the half-shaped patch pin are parallel, and the part connecting the two terminals in the middle is buried inside the terminal block, and one terminal of the semi-formed chip pin is disposed on the horizontal outer surface of the terminal block, and the terminal head does not exceed the terminal a horizontal outer surface for connecting the transformer and the PCB; the other terminal of the semi-formed patch extends out of the vertical outer surface of the terminal block for fixing the winding end of the winding, thereby separating the winding end from the patch end, The height of the transformer can be further reduced.

Fifth embodiment

Different from the above four embodiments, after the winding of each structure of the transformer and the original secondary winding of the power transformer is completed, two or more of the terminal blocks 211 can be connected by one or more wires. The pins are connected to two or more pins on the terminal block 221, and two or more pins on the terminal block 212 can be connected to the terminal block 222 through one or more wires. Two or more pins are connected, and two or more pins of the upper and lower sides on the same side of the vertical plane are directly connected without a coil, and the connection between the pin and the PCB substrate may be a signal connection point. In place of the traditional multi-PCB, the electrical connection scheme must be realized through terminal connection or transformer extension terminal. For example, the upper substrate is used as the input side of the switching power supply, the lower substrate is used as the output side of the switching power supply, and the switching power supply is passed through the transformer and the optocoupler. To achieve electrical isolation, the optocoupler is placed on the lower substrate, then the signal of the optocoupler can be transmitted to the upper substrate by connecting two wires to the input side.

Wires connecting two or more pins can also be automated, and the wires are placed on the same side of the transformer core, so the wires do not affect the installation and removal of the core, which saves process and facilitates production.

The above is only a preferred embodiment of the present invention, and it should be noted that the above preferred embodiments are not to be construed as limiting the invention. It will be apparent to those skilled in the art that several modifications and refinements can be made without departing from the spirit and scope of the present invention. For example, for the convenience of coil winding, a plurality of wire grooves or bosses are added to the skeleton. These improvements and refinements are also considered to be within the scope of the present invention, and the scope of the present invention is defined by the scope of the claims.

Claims

A transformer comprising a pair of combined cores and a skeleton, wherein the skeleton comprises a hollow winding portion, the winding portion is used for winding winding, and the hollow portion of the winding portion is used for carrying a combined core a first baffle and a second baffle disposed at two ends of the winding portion in a direction perpendicular to a central axis of the winding portion, the first baffle and the second baffle being parallel for limiting the winding a first terminal block and a second terminal block are disposed at two ends of the first baffle, and a third terminal block and a fourth terminal block are disposed at two ends of the second baffle, and the first terminal block And the horizontal inner surface of the second terminal block is in the same plane as the inner surface of the first baffle, and the horizontal inner surfaces of the third terminal block and the fourth terminal block are in the same plane as the inner surface of the second baffle, Each terminal block is provided with a set of pins on the horizontal outer surface.
A transformer according to claim 1, wherein a horizontal outer surface of said first terminal block and said second terminal block is higher than an outer surface of said first baffle, said third terminal block and said fourth terminal The horizontal outer surface of the table is higher than the outer surface of the second baffle.
A transformer according to claim 2, wherein two or more pins on said first terminal block and two on said third terminal block are passed through one or more wires One or more pins are connected, or two or more pins on the second terminal block and two or more leads on the fourth terminal block are connected by one or more wires The feet are connected.
A transformer according to claim 3, wherein said pin is a pin pin.
A transformer according to claim 4, wherein said pin pins are used to fix the winding head of the winding, and the transformer is electrically connected to the circuit board through the pin pins.
A transformer according to claim 4, wherein said pin pin is a pin pin bent into an L shape, and a bending point of the L-shaped pin pin is buried inside the terminal block, L One end of the pin pin extends out of the horizontal outer surface of the terminal block, and the other end of the L-shaped pin extends out of the vertical outer surface of the terminal block.
A transformer according to claim 3, wherein said pin is a chip pin, said chip pin is disposed on a horizontal outer surface of the terminal block, and one end of said chip pin is beyond The horizontal outer surface of the terminal block.
A transformer according to claim 7 wherein said chip pins are used to secure the winding ends of the windings and the transformer is electrically connected to the board via the chip pins.
A transformer according to claim 7, wherein said chip pin is a semi-finished chip pin having two terminals, and two terminals of said half-shaped chip pin are parallel. The part connecting the two terminals in the middle is buried inside the terminal block, and one terminal of the semi-formed chip pin is horizontally disposed on the horizontal outer surface of the terminal block, and the terminal head does not exceed the horizontal outer surface of the terminal block; the other half of the semi-formed patch A terminal extends out of the vertical outer surface of the terminal block.
A transformer according to any of the preceding claims wherein said pair of combined cores are held together by an insulative core tape which surrounds at least one of the cores.