CN113438801A

CN113438801A - PCB circuit convenient to heat dissipation

Info

Publication number: CN113438801A
Application number: CN202110765879.9A
Authority: CN
Inventors: 陈岚; 付康; 万志翀; 周志鹏
Original assignee: Shanghai Institute of Technology
Current assignee: Shanghai Institute of Technology
Priority date: 2021-07-06
Filing date: 2021-07-06
Publication date: 2021-09-24

Abstract

The invention provides a PCB circuit convenient for heat dissipation, which comprises a PCB; a plurality of first heating elements and a plurality of second heating elements are arranged on the front side surface of the PCB; the heat generation amount of the first heating element is larger than that of the second heating element; the first heating element is provided with a mounting hole, and a heat dissipation through hole for heat dissipation is formed below the mounting hole of the PCB; and a heat conducting through hole for heat dissipation is formed below the second heating element of the PCB. The PCB board adopts the design of 4 laminated layers, and each layer is provided with a base layer and a copper-clad area which are mutually laminated. The thickness of the copper-clad area of each layer in the PCB board is the same. The basic unit is aluminium base heat-conducting layer, every layer aluminium base heat-conducting layer thickness in the PCB stromatolite the same. The PCB board adopts the design of four laminated layers, and compared with a double-layer PCB, the simulation overall result shows that: the overall maximum temperature of the four-layer PCB is reduced by about 20 ℃ compared with the overall maximum temperature of the two-layer PCB.

Description

PCB circuit convenient to heat dissipation

Technical Field

The invention relates to the field of automotive electronics, in particular to a PCB circuit convenient for heat dissipation, which can be used as an automotive gauge LED driving circuit.

Background

With the development of electronic design and manufacturing industries, electronic and related industries have focused on the development of light, thin, short, small and high performance electronic components, and in a PCB board containing heating components such as a power tube, a magnetic core device, and a power resistor, the heat dissipation capability directly affects the maximum working environment temperature of the whole product and the product life.

Most of the commonly used heat dissipation methods at present are: 1. the PCB is coated with copper through the inner layer of the PCB, the heat of the heating element is dispersed to the copper-coated layer to realize the heat dissipation of the PCB, but the common copper-coated layer can hardly meet the heat dissipation requirement along with the increasing power consumption of the heating element; 2. the surface of the power tube is pasted with a heat dissipation aluminum sheet, the heat dissipation method only achieves local heat dissipation, and the integral heat dissipation condition of the PCB is not considered.

In view of the above disadvantages of conventional heat dissipation, a convenient and efficient heat dissipation method is needed.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a PCB circuit convenient for heat dissipation, which can be used as a vehicle-scale LED driving circuit.

The PCB circuit convenient for heat dissipation provided by the invention comprises a PCB; a plurality of first heating elements and a plurality of second heating elements are arranged on the front side surface of the PCB; the heat generation amount of the first heating element is larger than that of the second heating element;

the first heating element is provided with a mounting hole, and a heat dissipation through hole for heat dissipation is formed below the mounting hole of the PCB; and a heat conducting through hole for heat dissipation is formed below the second heating element of the PCB.

Preferably, the PCB board adopts a 4-layer-stacked design, and each layer is provided with a base layer and a copper-clad area which are mutually overlapped.

Preferably, the thickness of the copper-clad area of each layer in the PCB board is the same.

Preferably, the base layer is an aluminum-based heat conduction layer, and the thickness of each aluminum-based heat conduction layer in the PCB lamination layer is the same.

Preferably, the heat conducting via hole connects the multi-layer copper-clad area and the aluminum-based heat conducting layer.

Preferably, the mounting hole and the heat dissipation through hole are concentrically arranged.

Preferably, the heat dissipation through hole is internally covered with a metal layer;

and the back surface of the PCB is provided with a heat dissipation metal sheet, and the heat dissipation metal sheet is connected with the metal layer covered in the heat dissipation through hole.

Preferably, a heat sink is mounted on the back surface of the PCB, and the heat dissipation metal sheet is connected to the heat sink.

Preferably, the first heating element at least comprises any one or more of an STM32 chip module, a high-power triode and a voltage stabilizer;

the second heating element includes at least any one or any plural of a resistor and a capacitor.

Preferably, the number of the heat conducting through holes is multiple, and the heat conducting through holes are closely arranged.

Compared with the prior art, the invention has the following beneficial effects:

1. the PCB board adopts the design of four laminated layers, and compared with a double-layer PCB, the simulation overall result shows that: the overall maximum temperature of the four-layer PCB is reduced by about 20 ℃ compared with that of the double-layer PCB;

2. the PCB board base layer adopts the aluminum-based heat conduction layer, and compared with the FR4 base layer, the aluminum-based heat conduction layer can more rapidly reduce the temperature of the PCB board, and the difference of the whole highest temperature is about 30 ℃;

3. the heat conducting through hole can quickly transfer the heat of the low-heating low-power consumption element into the radiator, and then the heat is transferred into the air by the radiator to reduce the temperature of the heating element;

4. according to the invention, the installation holes are formed in the high-heating high-power-consumption element and the concentric heat dissipation through holes are formed in the PCB, so that the heat of the high-power-consumption element can be transferred to the heat dissipation metal sheet connected with the heat dissipation through holes from the heat dissipation through holes on the surface of the PCB, and then the heat is transferred to the radiator through the heat dissipation through holes by the heat dissipation metal sheet, and the heat dissipation of the high-power-consumption element can be rapidly realized.

Drawings

Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:

FIG. 1 is a circuit diagram of a PCB of a vehicle-scale LED driving circuit according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a PCB circuit facilitating heat dissipation according to an embodiment of the present invention;

FIGS. 3 (a), (b), (c), (d) are graphs comparing simulation results of a two-layer PCB stack design and a 4-layer PCB stack design in an embodiment of the present invention;

fig. 4 (a), (b) are graphs showing comparison of simulation results of using FR4 base layer and aluminum base layer in the embodiment of the present invention;

FIG. 5 is a cross-sectional view of a PCB circuit that facilitates heat dissipation in an embodiment of the present invention;

FIG. 6 is a top view of a PCB circuit that facilitates heat dissipation in an embodiment of the present invention;

fig. 7 is a back view of a PCB board circuit facilitating heat dissipation in an embodiment of the present invention.

In the figure: 1 is the STM32 chip, and 2.1 is first resistance element, and 2.2 are the low-power triode, and 2.3 is second resistance element, and 3 are the high power triode, and 4 are the PCB board, and 5 are the mounting hole, and 6 are the heat dissipation sheetmetal, and 7 are the radiator, and 8 are the heat conduction via hole, and 9 are aluminium base heat-conducting layer, and 10 are covering copper, and 11 are the heat dissipation through-hole.

Detailed Description

The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications can be made by persons skilled in the art without departing from the spirit of the invention. All falling within the scope of the present invention.

Fig. 1 is a circuit diagram of a PCB board of a vehicle-scale LED driving circuit according to an embodiment of the present invention, as shown in fig. 1, an STM32 chip, a plurality of resistor elements R1-R12, a plurality of capacitor elements C1-C6, a low-power transistor Q1-Q3, a high-power transistor U2, a resistor capacitor and a low-power transistor default to a low-power low-heat element, a high-power transistor default to a high-power high-heat element, and all elements are arranged in an array.

Fig. 2 is a schematic diagram of a circuit of a PCB board convenient for heat dissipation according to an embodiment of the present invention, as shown in fig. 2, the PCB board is provided with a plurality of first heat generating elements and second heat generating elements; the heat generation amount of the first heating element is larger than that of the second heating element;

the first heating element is provided with a mounting hole, and the PCB is provided with a heat dissipation through hole for heat dissipation below the mounting hole; and a heat conducting through hole for heat dissipation is formed below the second heating element of the PCB.

The PCB board adopts 4-layer laminated design, the copper-clad area 10 is positioned in the PCB board, and each layer is provided with a base layer and a copper-clad area. As shown in fig. 3, the overall maximum temperature of the PCB panel using the 4-layer stacked design is reduced by about 20 ℃.

In the embodiment of the present invention, the aluminum-based heat conduction layer 9 is used as the PCB substrate, and a simulation compared with the FR4 substrate is shown in fig. 4, it can be found that the maximum temperature of the whole PCB 4 is reduced by about 30 ℃ by using the aluminum-based heat conduction layer 9 compared with using the FR4 substrate.

Further, the PCB 4 is copper clad 10loz thick per layer, and if the average thickness of the copper clad area is expressed herein in terms of weight per area, i.e., the copper weight per square foot is about 28.35g, the aluminum based heat conductive layer 9 of each layer is uniform in thickness and the specific thickness can be determined by the PCB size.

Fig. 5 is a cross-sectional view of a PCB circuit facilitating heat dissipation in the embodiment of the present invention, and fig. 6 is a top view of the PCB circuit facilitating heat dissipation in the embodiment of the present invention, as shown in fig. 5, for heat dissipation of resistors 2.1, 2.3 and a low-power transistor 2.2, a heat conducting via 8 is formed in a bottom region of the heat conducting via, and the number of the heat conducting via 8 may be determined according to the size of an element and actual power consumption, and theoretically, the number of the heat conducting vias may be increased to accelerate heat dissipation of the element without affecting the layout of the PCB traces.

As shown in fig. 5 and 6, for the heat dissipation of the high-power triode 3, a mounting hole 5 is formed on the high-power triode 3, a heat dissipation through hole 11 is formed on the PCB board, and the heat dissipation through hole 11 is concentrically arranged with the mounting hole 5; and a metal layer is covered in the heat dissipation through hole 11 on the PCB board 4 and is connected with the heat dissipation metal sheets 6 on the two sides of the PCB board 4. The high-power triode 3 is provided with a metal welding point and can be fixedly connected with the heat dissipation metal layer 6 in a welding mode. The metal layer in the heat dissipating through hole 11 and the heat dissipating metal sheet 6 on the PCB 4 may be made of metal such as copper, tin, etc. for easy soldering.

The shape of the heat dissipation through hole 11 on the PCB board 4 can be circular, rectangular, oval and the like which are convenient to process, and the size can be designed according to the actual size of the PCB board.

Further, the heat-dissipating metal sheet 6 may be a circle, a rectangle, an ellipse, etc. for easy processing, and its thickness may be determined according to the actual size of the PCB board.

Fig. 7 is a back view of the PCB circuit facilitating heat dissipation in the embodiment of the present invention, as shown in fig. 7, a heat sink 7 directly connected to the heat dissipation metal sheet 6 is disposed on the back of the PCB 4, and the first resistance element 2.1, the second resistance element 2.3, and the low power transistor 2.2 can dissipate heat of the device to the heat sink 7 through the heat conduction via 8, and then to the air through the heat sink 7; the high-power triode 3 can transfer the heat of the components from the heat dissipation through hole 11 on the surface of the PCB 4 to the heat dissipation metal sheet 6 connected with the heat dissipation through hole 11, then the heat is transferred to the radiator 7 through the heat dissipation through hole 11 by the heat dissipation metal sheet 6, and finally the heat is dissipated to the air by the radiator 7.

In the embodiment of the invention, the PCB board adopts a four-layer-stacked design, and compared with a double-layer PCB, the simulation overall result shows that: the overall maximum temperature of the four-layer PCB is reduced by about 20 ℃ compared with that of the double-layer PCB; the PCB board base layer adopts the aluminum base layer, compared with the FR4 base layer, the aluminum base layer can more rapidly reduce the temperature of the PCB board, and the difference of the whole highest temperature is about 30 ℃; the heat conducting through hole can quickly transfer the heat of the low-heating low-power consumption element into the radiator, and then the heat is transferred into the air by the radiator to reduce the temperature of the heating element; according to the invention, the installation holes are formed in the high-heating high-power-consumption element and the concentric heat dissipation through holes are formed in the PCB, so that the heat of the high-power-consumption element can be transferred to the heat dissipation metal sheet connected with the heat dissipation through holes from the heat dissipation through holes on the surface of the PCB, and then the heat is transferred to the radiator through the heat dissipation through holes by the heat dissipation metal sheet, and the heat dissipation of the high-power-consumption element can be rapidly realized.

The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes and modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention.

Claims

1. A PCB circuit convenient for heat dissipation is characterized by comprising a PCB; a plurality of first heating elements and a plurality of second heating elements are arranged on the front side surface of the PCB; the heat generation amount of the first heating element is larger than that of the second heating element;

2. The PCB circuit for facilitating heat dissipation of claim 1, wherein the PCB is designed to be 4 laminated layers, and each layer is provided with a base layer and a copper-clad area which are laminated with each other.

3. The PCB circuit for facilitating heat dissipation of claim 2, wherein the copper-clad area of each layer of the PCB is the same in thickness.

4. The PCB board circuit facilitating heat dissipation of claim 2, wherein the base layer is an aluminum-based heat conducting layer, and the thickness of each aluminum-based heat conducting layer in the PCB laminate is the same.

5. The PCB circuit for facilitating heat dissipation of claim 4, wherein the thermally conductive via connects the multi-layer copper-clad region and the aluminum-based thermally conductive layer.

6. The PCB board circuit facilitating heat dissipation of claim 1, wherein the mounting hole and the heat dissipation through hole are concentrically arranged.

7. The PCB circuit convenient for heat dissipation of claim 1, wherein the heat dissipation through hole is internally covered with a metal layer;

8. The PCB circuit for facilitating heat dissipation of claim 7, wherein a heat sink is mounted on the back side of the PCB, and the heat dissipation metal sheet is connected with the heat sink.

9. The PCB circuit for facilitating heat dissipation of claim 1, wherein the first heat generating element comprises at least any one or more of an STM32 chip module, a high-power triode and a voltage regulator;

10. The PCB circuit for facilitating heat dissipation of claim 1, wherein the number of the heat conducting vias is plural, and the heat conducting vias are closely arranged.