CN213816118U

CN213816118U - Packaging structure of SMD linear constant current IC

Info

Publication number: CN213816118U
Application number: CN202022952910.3U
Authority: CN
Inventors: 肖亮; 张伟
Original assignee: Guagnzhou Tianxin Photoelectric Co ltd
Current assignee: Guagnzhou Tianxin Photoelectric Co ltd
Priority date: 2020-12-08
Filing date: 2020-12-08
Publication date: 2021-07-27
Anticipated expiration: 2030-12-08

Abstract

The utility model discloses a linear constant current IC's of SMD packaging structure relates to the chip technology. The scheme is provided aiming at the problems of poor heat dissipation and the like in the prior art, and four wiring pieces are arranged on the upper surface of the ceramic substrate; all lead terminals with the same function of the constant current IC are connected to the same wiring piece through gold wires respectively. The four wiring pieces extend to the lower surface of the ceramic substrate through the through holes respectively; the lower surface of the ceramic substrate is also provided with a heat dissipation conducting pad; the upper surface of the ceramic substrate is provided with a protective layer for sealing all the constant-current ICs, the wiring pieces and the gold wires. The ceramic substrate has the advantages that the size controllability of the ceramic substrate is high, and the heat dissipation conducting pad can be arranged. No matter how many the quantity of constant current IC changes, all have four pins to the outside, and the pin wiring reduces and enables the size of packaging structure to also further reduce. The wiring complexity is effectively reduced to the special design of wiring piece, and simple wiring is favorable to the thermal diffusivity to promote.

Description

Packaging structure of SMD linear constant current IC

Technical Field

The utility model relates to a IC packaging structure especially relates to a linear constant current IC's of SMD packaging structure.

Background

The conventional constant current IC is generally led out by a plurality of pins, and has a large volume. The package structure of the conventional constant-current IC product is shown in fig. 1, and the overall size of the product is generally over 5 × 5mm, and there is no dedicated heat dissipation pad structure. One constant current IC at least corresponds to four pins, and when the number of the constant current ICs rises, the size and the heat dissipation problems brought by the pins become more and more obvious.

The metal and plastic are packaged by plastic or epoxy resin, and the expansion coefficient difference between the metal and the plastic is large, so that the metal and plastic are used in an environment with high temperature difference in the actual use process, the gold wires connected inside deform and even break, and the failure probability is increased. In addition, the packaging material has low thermal conductivity and high thermal resistance, so that the temperature sensitivity is not high, and the temperature cannot be timely synchronized with a power device. The temperature of the power device exceeds the temperature difference of the linear IC by 10 ℃ or more, and the power device cannot respond in time when needing linear regulation and control at a specified temperature, so that the product can run at an overhigh temperature. Thereby causing the service life of the product to be reduced and even damaged, or causing the self temperature to be overhigh due to overlarge self thermal resistance and poor heat dissipation. And the power device starts linear constant current under the condition of lower temperature, so that the running power of the power device is insufficient, and the expected stable power effect cannot be achieved.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a linear constant current IC's of SMD packaging structure to solve the problem that above-mentioned prior art exists.

The utility model discloses a chip type linear constant current IC packaging structure, which comprises a ceramic substrate and more than one constant current IC arranged above the ceramic substrate; four wiring pieces are arranged on the upper surface of the ceramic substrate; the positive terminals of all the constant-current ICs are electrically connected with the first wiring piece through gold wires, the negative terminals of all the constant-current ICs are electrically connected with the second wiring piece through gold wires, the grounding terminals of all the constant-current ICs are electrically connected with the third wiring piece through gold wires, and the regulating terminals of all the constant-current ICs are electrically connected with the fourth wiring piece through gold wires; the four wiring pieces extend to the lower surface of the ceramic substrate through the through holes respectively; the lower surface of the ceramic substrate is also provided with a heat dissipation conducting pad; the upper surface of the ceramic substrate is provided with a protective layer for sealing all the constant-current ICs, the wiring pieces and the gold wires.

The ceramic substrate upper surface be equipped with the boss, all constant current IC sets up on the boss.

The wire connector comprises a surface conductive pad, an extension part, a bottom conductive pad and a through hole; the surface conducting pad is arranged at one corner of the upper surface of the ceramic substrate, the bottom conducting pad is arranged at the corresponding corner of the lower surface of the ceramic substrate, and the bottom conducting pad and the surface conducting pad are electrically connected through a through hole; the extension part is arranged on the upper surface of the ceramic substrate, one end of the extension part is connected with the surface conductive pad, and the other end of the extension part freely extends towards the adjacent corner.

The bottom conductive pad extends towards the middle along the short edge of the ceramic substrate.

The extension part extends along the long side of the ceramic substrate to the other corner part.

And the two extending parts on the same long edge of the ceramic substrate are in complementary pair.

The ceramic substrate has the size of 5.4 mm-6.0 mm in length and 1.9 mm-2.5 mm in width, and preferably has the size of 5.7mm in length and 2.2mm in width.

The boss size be 5.5mm long, wide 1 mm.

A linear constant current IC's of SMD packaging structure, its advantage lies in, utilizes the ceramic substrate size controllability high, can also set up the heat dissipation conducting pad. No matter how many the quantity of constant current IC changes, all have four pins to the outside, and the pin wiring reduces and enables the size of packaging structure to also further reduce. The wiring complexity is effectively reduced to the special design of wiring piece, and simple wiring is favorable to the thermal diffusivity to promote. Because the heat dissipation is improved, the constant current IC can work under higher power, and is particularly suitable for driving a light source of an automobile headlamp.

Drawings

Fig. 1 is a schematic structural diagram of a patch type linear constant current IC package structure in the prior art.

Fig. 2 is a schematic structural diagram of the package structure of the present invention;

FIG. 3 is a cross-sectional view taken along line A-A of FIG. 2;

FIG. 4 is a schematic structural view of the junction block of the present invention;

FIG. 5 is a right side view of the wire connector of the present invention;

fig. 6 is a rear view of the package structure of the present invention.

Reference numerals:

10-ceramic substrate, 11-boss, 12-protective layer;

20-wire connector, 21-surface conductive pad, 22-extension, 23-bottom conductive pad, 24-via, 25-heat dissipating conductive pad;

30-constant current IC, 31-gold wire.

Detailed Description

As shown in fig. 2-6, the present invention relates to a chip type linear constant current IC package structure, which includes a rectangular ceramic substrate 10 and a constant current IC30 disposed on the ceramic substrate 10. The ceramic substrate 10 has a dimension length of 5.7 + -0.3 mm and a width of 2.2 + -0.3 mm, and preferably has a dimension of 5.7mm × 2.2 mm. In order to reduce the wiring difficulty, a boss 11 extending in the same direction protrudes on the upper surface of the ceramic substrate 10. The length of the boss 11 is slightly smaller than that of the ceramic substrate 10, and the width is about 1/2 of the ceramic substrate 10, for example, the length and width of the boss 11 is selected to be 5.5mm × 1mm based on the preferred size of the ceramic substrate 10. The boss 11 is preferably located at the center of the ceramic substrate 10, and the opposite spaces between the long sides of the two sides and the ceramic substrate 10 are used for accommodating all the collinear metal layers.

The constant current IC30 can be configured with 1 to 16 ICs of the same type according to different applications. In general, 1 to 8 ICs are suitable for the light source scene of the automobile headlamp. All of the constant current ICs 30 are evenly spaced and distributed in parallel along the extension of the boss 11. All of the constant current ICs 30 are placed so that all of the terminals with the same function are on the same side, in order to simplify the wiring scheme, i.e., all of the positive terminals are on the left side of the boss 11.

The collinear metal layer can be obtained by etching the same metal layer, so that wiring metal pairs with symmetrical structures are divided between the long sides of the boss 11 and the ceramic substrate 10. The wiring metal pair is composed of two complementary extended metal strips, including surface conductive pads 21 and extensions 22. The extension 22 has one end connected to the surface pad 21 and the other end freely extending toward the other metal strip surface pad 21 disposed in pair. All the surface conductive pads 21 are disposed at the corner positions of the upper surface of the ceramic substrate 10, and bottom conductive pads 23 corresponding to the upper surface conductive pads 21 one by one are disposed at the corner positions of the lower surface of the ceramic substrate 10. The bottom conductive pad 23 and the surface conductive pad 21 are electrically connected by a via 24. The bottom conductive pad 23 extends from the corner portion to the middle portion along the short side of the ceramic substrate 10, so that the heat dissipation conductive pad 25 can be kept rectangular when the bonding area is enlarged, thereby reducing the process difficulty. The surface conductive pad 21, the extension 22, the bottom conductive pad 23 and the via 24, which are connected to each other, together constitute a wiring member 20.

The heat dissipation conductive pad 25 is located on the lower surface of the ceramic substrate 10 and can be made of a heat sink metal. The long sides of the heat-dissipating pads 25 are as close as possible to the corresponding long sides of the ceramic substrate 10, and the short sides of the heat-dissipating pads 25 are as close as possible to the bottom pads 23 without contacting. The purpose is to fill the lower surface of the ceramic substrate 10 with the heat-dissipating conductive pads 25 as much as possible to improve the heat-dissipating efficiency.

All the terminals of the constant current IC30 with the same function are connected to the same extension 22 through gold wires 31, and the common constant current IC30 includes a positive terminal, a negative terminal, a ground terminal, and a control terminal. All positive terminals are electrically connected with the first wiring piece through gold wires, all negative terminals are electrically connected with the second wiring piece through gold wires, all grounding terminals are electrically connected with the third wiring piece through gold wires, and all regulation and control terminals are electrically connected with the fourth wiring piece through gold wires.

Finally, a protection layer 12 is disposed on the upper surface of the ceramic substrate 10 to seal all the surface conductive pads 21, the extension portions 22, the constant current IC30 and the gold wires 31, thereby forming a complete package structure.

The standard current corresponding to different models is different by adjusting the different models of all the constant current ICs so as to adjust the magnitude of the external constant current. For example, 5 constant current ICs use a model corresponding to 200 milliamperes at the same time, and the external constant current is 1000 milliamperes; the 8 constant current ICs simultaneously use 300 milliamperes, and the external current is 2400 milliamperes, so that the packaging mode with large-range constant current can be realized. The IC packaging structure is compact and compact, the performance of the ceramic circuit is stable, the size of a ceramic single-grain cutting product is accurate, full-automatic equipment can be adopted for sorting and packaging, and the consistency of products produced in large-scale production is good. The wiring is simple, and good heat dissipation can make the product work under higher power environment. Due to the advantages of the product in the aspects of size and performance, the product competitiveness of downstream enterprises can be effectively improved.

Various other modifications and changes may be made by those skilled in the art based on the above-described technical solutions and concepts, and all such modifications and changes are intended to fall within the scope of the claims.

Claims

1. A packaging structure of a patch type linear constant current IC is characterized by comprising a ceramic substrate (10) and more than one constant current IC (30) arranged above the ceramic substrate (10); four wiring pieces (20) are arranged on the upper surface of the ceramic substrate (10); the positive terminals of all the constant-current ICs (30) are electrically connected with the first wiring piece through gold wires, the negative terminals are electrically connected with the second wiring piece through gold wires, the grounding terminals are electrically connected with the third wiring piece through gold wires, and the regulating terminals are electrically connected with the fourth wiring piece through gold wires; the four wiring pieces (20) respectively extend to the lower surface of the ceramic substrate (10) through the through holes (24); the lower surface of the ceramic substrate (10) is also provided with a heat dissipation conducting pad (25); the upper surface of the ceramic substrate (10) is provided with a protective layer (12) for sealing all the constant current IC (30), the wiring piece (20) and the gold wire.

2. The packaging structure of the patch type linear constant current IC according to claim 1, wherein bosses (11) are provided on the upper surface of the ceramic substrate (10), and all the constant current ICs (30) are provided on the bosses (11).

3. The package structure of the patch type linear constant current IC according to claim 1, wherein the wiring member (20) includes a surface conductive pad (21), an extension portion (22), a bottom conductive pad (23), and a via hole (24); the surface conductive pad (21) is arranged at one corner of the upper surface of the ceramic substrate (10), the bottom conductive pad (23) is arranged at the corresponding corner of the lower surface of the ceramic substrate (10), and the bottom conductive pad (23) and the surface conductive pad (21) are electrically connected through a through hole (24); the extension part (22) is arranged on the upper surface of the ceramic substrate (10), one end of the extension part is connected with the surface conductive pad (21), and the other end of the extension part freely extends towards the adjacent corner.

4. The package structure of the chip type linear constant current IC according to claim 3, wherein the bottom conductive pad (23) extends along a short edge of the ceramic substrate (10) toward a middle portion.

5. The package structure of the patch type linear constant current IC according to claim 4, wherein the extension portion (22) extends along a long side of the ceramic substrate (10) to another corner portion.

6. The packaging structure of the patch type linear constant current IC according to claim 5, wherein the two extending portions (22) on the same long side of the ceramic substrate (10) are complementary to each other.

7. The packaging structure of the patch type linear constant current IC according to any one of claims 1 to 6, wherein the ceramic substrate (10) has a length of 5.4mm to 6.0mm and a width of 1.9mm to 2.5 mm.

8. The package structure of the patch type linear constant current IC according to claim 7, wherein the ceramic substrate (10) has a length of 5.7mm and a width of 2.2 mm.

9. The packaging structure of the patch type linear constant current IC according to claim 2, wherein the size of the boss (11) is 5.5mm long and 1mm wide.