The utility model content
At the prior art above shortcomings, it is strong that the purpose of this utility model provides a kind of not only heat-sinking capability, and the radiator structure of surface mounting high-power element simple in structure, that manufacturing cost is lower.
The purpose of this utility model is achieved in that the radiator structure of surface mounting high-power element, is used for the heat that the conduction and high power element gives out, and it is characterized in that, comprising:
-circuit board, the radiating surface of high-power components directly weld with the front that is embedded in the heat conduction copper billet in the circuit board;
-heat conduction copper billet, heat conduction copper billet be embedded in the circuit board and thickness the same with circuit board, the heat conduction copper billet has good heat conductivility;
-heating panel, the one side of heating panel and the reverse side welding that is embedded in heat conduction copper billet in the circuit board, another side connects heat-dissipating casing;
-heat-dissipating casing is used for heat is distributed in the air.
Further feature, described high-power components adopts the form of paster encapsulation.
The installation of described high-power components be by welding be embedded in circuit board on the front of heat conduction copper billet be connected.
Be coated with copper pad on heating panel, heating panel is by copper pad and the reverse side welding that is embedded in heat conduction copper billet on the circuit board.
Compared to existing technology, the utlity model has following advantage:
Owing on circuit board, inlay (among Fig. 2) heat conduction copper billet 7, (among Fig. 1) plated-through hole 2 that replaces prior art, the long-pending plated-through hole 2 in Fig. 1 of the heat-conducting section of heat conduction copper billet 7, so the heat of high-power components 1 just can be transmitted to the reverse side of circuit board 3 fast, be delivered to heat-dissipating casing 6 through aluminium base heating panel 5 again, heat conducted in the air by heat-dissipating casing 6.In the utility model, heat conduction copper billet 7 is directly to be welded on the aluminium base heating panel 5 by the copper pad 8 above the aluminium base heating panel 5 with welding method, and there is one deck chlorine monoxid insulating barrier on aluminium base heating panel 5 surfaces, copper pad 8 is tightly to be attached to the oxide isolated laminar surface of aluminium base heating panel 5 and to insulate with aluminium base by special processing, so just save the heat-conducting insulation material 4 among Fig. 1, also further reduced thermal resistance, be transmitted to purpose on the heat-radiating aluminum plate fast thereby reached the heat that will be in the high-power components 1 produces, thereby solved the problem of the quick heat radiating of high-power components.And structure is simpler, and manufacturing cost is lower.
The utility model adopts from high-power components-heat conduction copper billet-with the path of aluminium base heating panel-fin-air heat radiation of copper pad, effectively reduce the working temperature of high-power components, it is following that the high-power components working temperature is remained in the specified scope, satisfied the specification requirement of vehicle electronic device.
Embodiment
Embodiment 1: referring to Fig. 2, a kind of radiator structure of surface mounting high-power element is used for the heat that the conduction and high power element gives out, and comprising: circuit board, the radiating surface of high-power components 1 directly are welded on the front of the circuit board 3 that is inlaid with heat conduction copper billet 7; Heat conduction copper billet 7 be embedded in the circuit board 3 and thickness identical with circuit board 3, heat conduction copper billet 7 has good heat conductivility; The one side welding heat conduction copper billet 7 of heating panel 5, another side connects heat-dissipating casing 6; Heat-dissipating casing 6 is used for heat is conducted in the air.
The utility model is to fix a heat conduction copper billet 7 with the circuit board same thickness on the position of needs heat radiations of soldering surface mounted formula high-power components 1 in circuit board 3, and in board production, heat conduction copper billet 7 and circuit board 3 are set into one, in welding, high-power components 1 and heat conduction copper billet 7 are welded together, then a volume and the bigger heating panel 5 of area are welded on the another side of heat conduction copper billet 7 by scolding tin.
Described heating panel 5 adopts aluminium bases (the perhaps material of other good heat conductivity, such as materials such as copper, potteries) structure, aluminium base has perfect heat-dissipating, price is relatively low, manufacturing process is ripe, the advantage easily of drawing materials, thereby is applied in a large number in the radiator structure of power circuit.
Embodiment 2: as shown in Figure 2, be on the basis of embodiment 1, be coated with copper pad 8 on aluminium base heating panel 5, aluminium base heating panel 5 is by the reverse side welding of copper pad 8 with heat conduction copper billet 7.
Principle of the present utility model is: the heat that surface mounting high-power element 1 sends, directly pass to aluminium base heating panel 5 successively by the heat conduction copper billet 7 that is embedded in the circuit board 3, pass on the fin 6 of entire circuit through radiator aluminium base 5 again, the mode of surface mounting high-power element 1 by welding directly be embedded in circuit board 3 in heat conduction copper billet 7 be connected, heat conduction copper billet 7 is integrated by copper pad 8 welding with aluminium base heating panel 5, because the area of dissipation of aluminium base heating panel 5 is much larger than surface mounting high-power element 1, so it is just much smaller that aluminium base heating panel 5 is fixed on its thermal resistance of entire circuit shell, thereby just improved the efficient of heat transferred greatly.Not only the capacity of heat transmission is strong as heat carrier with the heat conduction copper billet, and easy to process, and manufacturing cost is lower.
The comparison of the capacity of heat transmission:
Thermal conductivity has two important parameters when calculating: thermal resistance and conductive coefficient.
Conductive coefficient is the thermal conduction characteristic of certain material, at shape size requirement is arranged;
Thermal resistance is at a certain fixed system, and strict size, thickness requirement are arranged, if change any part or size change, the thermal resistance of whole system all can change, corresponding to certain material, if overall dimension changes, thermal resistance also is different.
The homogenous material thermal resistance can be calculated by conductive coefficient and shape size.
Therefore, a kind of capacity of heat transmission of radiator structure will could clearly be represented by the calculating of system's thermal resistance.
The thermal source unanimity of this second mate figure can so be thought, the radiating mode capacity of heat transmission of system's thermal resistance minimum is just better.
The heat sink conception of Fig. 1:
R1 is the internal thermal resistance of MOSFET.It is a steady state value, often encapsulates to make when finishing at chip and has determined.Be about 1 ℃/W.
R2 is tin filling post (Sn63Pb37) thermal resistance in the aperture.The scolding tin conductive coefficient is 50W/m*K, totally 37 through holes, single hole sectional area 0.2mm
2, thickness 2mm.Expire if fill, single thermal resistance is 80 ℃/W, and total equivalent thermal resistance is 2.16 ℃/W.
R3 is a PCB substrate thermal resistance, and when material was FR4, conductive coefficient was generally 0.2W/m*K, and through hole is removed in the copper billet zone under the power chip, and the epoxy resin sectional area is 42.84mm altogether
2Its thermal resistance minimum is 233.4 ℃/W, and it is in parallel with the tin filling post, so it is little to the heat-sinking capability influence.
R4 is the heat conducting film thermal resistance, is 0.4 ℃/W.
R5 is the aluminium sheet thermal conductance, and area is 50.24mm
2, thickness 2mm.Conductive coefficient is 0.18 ℃/W.
R6 is an aluminium shell thermal resistance, supposes the shell unanimity, the thermal resistance unanimity of two kinds of comparative structures.
The heat sink conception of Fig. 2:
R1 is the internal thermal resistance of MOSFET.It is a steady state value, often encapsulates to make when finishing at chip and has determined.Be about 1 ℃/W.
R7 is the copper billet thermal resistance, sectional area 50.24mm
2, conductive coefficient 407W/m*K, the thermal resistance size is 0.01 ℃/W.
R8 is an aluminium base pad thermal resistance, has one deck Copper Foil and one deck zinc-plated on the pad, and zinc-plated and weld does not temporarily include, and copper thickness is generally 35 μ m, and the thermal resistance size is 0.000165 ℃/W, can ignore.
One deck layer Al that become attached to arranged between R5 and the R8
2O
396% aluminium oxide conductive coefficient is 30W/m*K, and 99% aluminium oxide conductive coefficient is 35W/m*K, calculates with lower 96% aluminium oxide here, calculate with R8 identical because thickness at 75 μ m between 155 μ m, be 0.1 ℃/W to the maximum.
R5 is an aluminium base, and area is 50.24mm
2, thickness 2mm.Conductive coefficient is 0.18 ℃/W.
R6 is an aluminium shell thermal resistance, supposes the shell unanimity, the thermal resistance unanimity of two kinds of comparative structures.
Equivalent thermal resistance except aluminium shell and chip internal thermal resistance and heat sink conception 1 is 2.74 ℃/W, and the equivalent thermal resistance of heat sink conception 2 is 0.29 ℃/W.Both differ 9.45 times.Calculate low 25 ℃ of the temperature rise of improved scheme 2 with the general dissipation power 10W of power chip commonly used.
The two identical welding portion is (1) and (2), between (1) and (7), supposes that welding procedure is identical, the thermal resistance unanimity.The utility model is not owing to use dielectric film, aluminium base also is to fit by welding and heat conduction copper billet, belonging to surface molecular merges, the contact-making surface gap is considerably less, the dielectric film that adopts with prior art (Fig. 1) compresses mode and (is confined to compress, still the surface of different materials contact) compare, contact heat resistance is lower; Moreover because prior art is used intensive through hole, because effect of surface tension, it is the comparison difficulty that whole holes will fully be filled up in the practical operation.When the power chip dissipation power was 10W in the reality, the utility model temperature after the improvement was than low 10 ℃ at least of prior aries (Fig. 1).