A high-power thin patch type bridge stack rectifier

Abstract

The application relates to a high-power thin patch bridge rectifier, which comprises an upper patch, a lower patch, four diode chips, an epoxy resin package and four pins extending from the epoxy resin package, a tapered hole is arranged in the middle of the epoxy resin package and extends along the thickness direction of the epoxy resin package, the four diode chips are distributed in a diamond shape around the tapered hole; a group of annularly arranged heat dissipation fins are arranged on the wall of the tapered hole, four heat pipes are arranged in the epoxy resin package, the evaporation section of the heat pipe is in heat conduction connection with one of the diode chips, and the condensation section extends to be welded and fixed with the heat dissipation fin group. The heat pipe is used for rapidly transferring the heat of the diode chips to the heat dissipation fin group at the tapered hole, air in the tapered hole is heated, the density of the air is reduced, the air is naturally lifted, cold air outside enters from the bottom of the tapered hole to be supplemented, a natural convection circulation is formed, a double heat dissipation effect composed of a temperature difference driven active heat dissipation and passive heat dissipation of the heat pipe and the heat dissipation fin group is formed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor devices, in particular to a high-power thin patch type bridge stack rectifier. BACKGROUND

[0002] The patch type bridge stack rectifier is a surface mount technology (SMT) rectifier device, and its core function is to convert alternating current into direct current, which is suitable for high-power and high-density circuit scenarios. Its characteristics are thinness, high-efficiency heat dissipation and large current carrying capacity, and its typical thickness is only 1.4-1.6 mm. It mainly adopts an upper and lower patch structure, and four diode chips are welded inside with tin paste, and the outside is plastic encapsulated with epoxy resin and extends out the lead.

[0003] The Chinese patent application with the application number CN202010599497.9 in the related art proposes a high-power thin patch type bridge stack rectifier, which comprises: a first diode chip, a second diode chip, a metal lead frame and an L-shaped metal lead. A plurality of first protrusions are distributed on the surface of the first welding strip of the metal lead frame, and the first welding strip and the first protrusions are connected with the positive electrode of the first diode chip and the second diode chip through the first solder layer. A plurality of second protrusions are distributed on the surface of the second welding strip of the L-shaped metal lead, and the second welding strip and the second protrusions are connected with the negative electrode of the first diode chip and the second diode chip through the second solder layer. The first welding strip of the metal lead frame and the second welding strip of the L-shaped metal lead each have a protruding portion on the region of the first diode chip and the second diode chip. The design of the first protrusions and the second protrusions avoids false welding, improves the reliability of the device, effectively prevents water vapor from entering the interior of the device, and improves the weather resistance and overall strength.

[0004] The related technology in the above has the following defects: The working current of the high-power thin patch type bridge stack rectifier can usually reach 8A and above, compared with the working current 4A of the conventional bridge stack rectifier. Such a high-power rectifier has greater demand for heat dissipation when working, and currently mainly relies on copper sheets and encapsulated epoxy resin for passive heat conduction, and there is a certain upper limit to the heat dissipation efficiency. Once the heat accumulated in the diode chip is too much, the diode chip will still be detached. SUMMARY

[0005] In order to improve the problem that the passive heat dissipation of the high-power patch type rectifier relying on copper sheets and epoxy resin cannot meet the demand, the present application provides a high-power thin patch type bridge stack rectifier.

[0006] The high-power thin patch type bridge stack rectifier provided by the present application adopts the following technical solution:

[0007] The application discloses a high-power thin patch bridge rectifier, which comprises an upper patch, a lower patch, four diode chips, an epoxy resin package and four pins extending from the epoxy resin package, a tapered hole is formed in the middle of the epoxy resin package and extends along the thickness direction of the epoxy resin package, the four diode chips are distributed in a rhombic shape around the tapered hole.

[0008] A group of annularly arranged heat dissipation fins are mounted on the wall of the tapered hole, four heat pipes are arranged in the epoxy resin package, the evaporation section of the heat pipe is in heat conduction connection with one of the diode chips, and the condensation section extends to be welded and fixed with the heat dissipation fin group.

[0009] Further, the upper patch comprises a first upper copper sheet and a second upper copper sheet arranged in an insulating mode and corresponding to two diode chips respectively, and the lower patch comprises a first lower copper sheet and a second lower copper sheet arranged in an insulating mode and corresponding to two diode chips respectively.

[0010] The two diode chips adjacent to the insulating parts of the first lower copper sheet and the second lower copper sheet correspond to the first upper copper sheet, and the two diode chips adjacent to the other insulating parts of the first lower copper sheet and the second lower copper sheet correspond to the second upper copper sheet.

[0011] Further, the first upper copper sheet and the second upper copper sheet are provided with first protrusions downward corresponding to the parts of the opposite two diode chips, and the first lower copper sheet and the second lower copper sheet are provided with second protrusions upward corresponding to the parts of the other opposite two diode chips.

[0012] The four diode chips comprise upper chips and lower chips arranged in a staggered mode in the vertical direction, the upper chips are located between the second protrusions and the first upper copper sheet or the second upper copper sheet, and the lower chips are located between the first protrusions and the first lower copper sheet or the second lower copper sheet.

[0013] Further, the heat dissipation fin group comprises two annular integral fins arranged in an axial direction and spaced apart along the tapered hole, the evaporation section of the heat pipe corresponding to the lower chip is located in the back groove of the corresponding first protrusion, and the condensation section is connected with the annular integral fin located above, and the evaporation section of the heat pipe corresponding to the upper chip is located in the back groove of the corresponding second protrusion, and the condensation section is connected with the annular integral fin located below.

[0014] Further, the condensation section of the heat pipe has a semicircular arc part matched with the annular integral fin, and the semicircular arc part is located on the upper end face of the annular integral fin.

[0015] Further, the annular integral fin is arranged in an inclined mode, and the inner edge end of the annular integral fin is closest to the upper end face of the epoxy resin package.

[0016] Further, the heat dissipation fin group further comprises a plurality of split fins arranged in an equidistant circumferential array along the axial direction of the tapered hole, the split fins being arranged on one side of the lower annular integral fin close to the lower end surface of the epoxy resin package, and a bimetallic sheet being fixed between the split fins and the wall of the tapered hole, the bimetallic sheet being configured to drive the split fins to flip towards the annular integral fin when the body temperature of the bimetallic sheet is greater than a set value.

[0017] Further, a honeycomb copper mesh ring is arranged between the bimetallic sheet and the adjacent annular integral fin on the wall of the tapered hole.

[0018] Further, a plurality of helical flow guide vanes arranged in an equidistant circumferential array along the axial direction of the tapered hole are fixed to the lower end surface of the epoxy resin package, the helical flow guide vanes being arranged radially along the tapered hole, and the side of the helical flow guide vanes away from the epoxy resin package being flush with the free end of the pin.

[0019] Further, an insulating heat conducting layer is arranged between the contact part of the heat pipe and the upper patch and the lower patch and / or between the contact part of the heat pipe and the heat dissipation fin group.

[0020] In summary, the beneficial technical effects of the present application are:

[0021] 1. By arranging two upper chips and two lower chips in the epoxy resin package in a staggered manner in the vertical direction, the heat dissipation between the two diode chips in the same layer is not interfered, and the heat dissipation between the two diode chips on the same side is staggered, so that the interference area between the heat dissipation spaces of each diode chip is minimal, which helps the diode chip to dissipate heat through the upper patch and the lower patch and the epoxy resin package, thereby improving the heat dissipation efficiency of the diode chip in an effective volume space;

[0022] 2. The heat pipe quickly transfers the heat of the diode chip to the heat dissipation fin group at the tapered hole in the middle of the epoxy resin package, so that the air in the tapered hole is heated and naturally rises due to the decrease in density, and the cold air outside enters from the bottom of the tapered hole to supplement, forming a natural convection circulation; and due to the arrangement of the tapered hole being smaller at the top and larger at the bottom, the suction force for the cold air at the bottom is enhanced, and the rapid outflow of hot air in the tapered hole is promoted, forming a double heat dissipation effect of active heat dissipation driven by temperature difference + passive heat dissipation of the heat pipe and the heat dissipation fin group, which can improve the heat air exhaust efficiency;

[0023] 3. Compared with the common straight hole, the conical hole has high air flow resistance, low flow rate, easy formation of "dead zone", short air flow residence time and other defects, and its essence is passive heat dissipation; the setting of the conical hole of the application can enhance the suction force of the cold air at the bottom, improve the air flow speed in the conical hole, promote the rapid exhaust of hot air, form high-efficiency circulation, and enhance the heat exchange effect of the cold air and the heat dissipation fin group, so that the comprehensive heat dissipation efficiency is obviously improved;

[0024] 4. By setting the upper and lower two annular integrated fins in different angles, materials, and numbers of ultra-thin fins, the difference in heat dissipation and cooling of the corresponding heat pipes caused by the different temperatures of the air flow contacting the two annular integrated fins can be reduced, and the working stability and service life of the four diode chips can be ensured;

[0025] 5. By setting the multiple split fins, bimetallic sheets and honeycomb copper mesh rings, the inclination angle of the split fins can be adjusted in real time according to the temperature at the root of the lower annular integrated fin, and then the air flow concentration of the conical hole inlet can be adjusted, so as to dynamically adjust the overall heat dissipation effect of the two annular integrated fins. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a schematic diagram of the overall structure of the embodiment of the application;

[0027] Figure 2 is a schematic diagram of the structure of the embodiment of the application after the epoxy resin package is hidden;

[0028] Figure 3 is a schematic diagram of the exploded structure of the embodiment of the application after the epoxy resin package is hidden;

[0029] Figure 4 is a schematic diagram of the cross-sectional structure along the A-A line in Figure 1 ;

[0030] Figure 5 is a schematic diagram of the cross-sectional structure along the B-B line in Figure 1 ;

[0031] Figure 6 is a schematic diagram of the local enlargement of the C part in Figure 4 ;

[0032] Figure 7 is a schematic diagram of the structure of the embodiment of the application mainly used to show the spiral flow guide piece.

[0033] Explanation of reference signs:

[0034] 11, upper patch; 111, first upper copper sheet; 112, second upper copper sheet; 113, first protruding part; 12, lower patch; 121, first lower copper sheet; 122, second lower copper sheet; 123, second protruding part;

[0035] 2, diode chip; 21, upper chip; 22, lower chip;

[0036] 3, epoxy resin package; 31, conical hole;

[0037] 4, pin;

[0038] 5, heat pipe; 51, semicircular arc part;

[0039] 61, annular integral fin; 62, split fin; 63, bimetallic strip; 64, honeycomb copper mesh ring;

[0040] 7, helical guide vane. DETAILED DESCRIPTION

[0041] The technical solutions of the present application will be described in detail below with reference to the drawings. Obviously, the described embodiments are only some of the embodiments of the present application, but not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0042] The present application discloses a high-power thin patch type bridge rectifier. Referring to Figure 1 、 Figure 2 and Figure 3 , which comprises an upper patch 11, a lower patch 12, four diode chips 2, an epoxy resin package 3 and four pins 4 extending from the epoxy resin package 3. A conical hole 31 is formed in the middle of the epoxy resin package 3 along the thickness direction, the taper of the conical hole 31 is 10°-15°, and the four diode chips 2 are distributed in a diamond shape around the conical hole 31. Among them, the side of the epoxy resin package 3 close to the free end of the pin 4 is the lower end face, and the other side is the upper end face.

[0043] A set of annular heat dissipation fins is installed on the wall of the conical hole 31, and four heat pipes 5 are arranged in the epoxy resin package 3, the evaporation section of the heat pipe 5 is in thermal conductive connection with one of the diode chips 2, and the condensation section extends to be welded and fixed with the heat dissipation fin set. Among them, the sintered copper heat pipe 5 is selected, the cross section is rectangular and the whole is flat, the internal working medium is water, and the reflux of the working medium in the condensation section and the evaporation section is realized by means of the capillary effect of the internal capillary pressure head.

[0044] Specifically, the upper patch 11 includes the first upper copper sheet 111 and the second upper copper sheet 112 which are insulated and correspond to the two diode chips 2 respectively, and the lower patch 12 includes the first lower copper sheet 121 and the second lower copper sheet 122 which are insulated and correspond to the two diode chips 2 respectively; the first upper copper sheet 111, the second upper copper sheet 112, the first lower copper sheet 121 and the second lower copper sheet 122 are all in the shape of triangle, and are provided with arc-shaped notches at the positions close to the tapered hole 31, so that the occupying area of the upper patch 11 and the lower patch 12 in the epoxy resin package 3 is as large as possible, and the good heat conduction effect of copper is utilized to achieve the high-efficiency heat dissipation effect of the rectifier of the present application.

[0045] Wherein, referring to Figure 2 and Figure 3 , the two diode chips 2 on the first lower copper sheet 121 and the second lower copper sheet 122 adjacent to the insulating portions thereof correspond to the first upper copper sheet 111, and the two diode chips 2 on the first lower copper sheet 121 and the second lower copper sheet 122 adjacent to the other insulating portions thereof correspond to the second upper copper sheet 112. That is, the insulating portions between the first upper copper sheet 111 and the second upper copper sheet 112 are arranged in a staggered manner with the insulating portions between the first lower copper sheet 121 and the second lower copper sheet 122, so as to satisfy the good rectification path of the four pins 4 connected to the first upper copper sheet 111, the second upper copper sheet 112, the first lower copper sheet 121 and the second lower copper sheet 122 respectively.

[0046] Further, the first upper copper sheet 111 and the second upper copper sheet 112 are provided with the first protruding portion 113 protruding downward at the positions corresponding to the two opposite diode chips 2, and the first lower copper sheet 121 and the second lower copper sheet 122 are provided with the second protruding portion 123 protruding upward at the positions corresponding to the other two opposite diode chips 2.

[0047] The four diode chips 2 include the upper chip 21 and the lower chip 22 which are arranged in a staggered manner in the vertical direction, the upper chip 21 is located between the second protruding portion 123 and the first upper copper sheet 111 or the second upper copper sheet 112, and the lower chip 22 is located between the first protruding portion 113 and the first lower copper sheet 121 or the second lower copper sheet 122.

[0048] Specifically, the flared end of the tapered hole 31 can be located on the upper end face of the epoxy resin package 3 or the lower end face of the epoxy resin package 3, when the flared end is located on the upper end face, it is used as the air outlet, the resistance of the hot air rising in the tapered hole 31 is smaller, which can effectively inhibit the turbulent flow and prolong the contact time of the cold and hot air; compared with the ordinary straight hole, the flared end air outlet tapered hole 31 can reduce the air flow resistance, reduce the turbulent flow, improve the flow continuity of the air in the tapered hole 31, and also prolong the contact time of the cold and hot air, so as to enhance the heat exchange effect of the cold air and the heat dissipation fin group.

[0049] When the flared end is located at the lower end surface, it is used as an air inlet, and the outlet of the tapered hole 31 is a small end. When air enters from the air inlet at the bottom end of the tapered hole 31, the air is gradually accelerated as the diameter of the tapered hole 31 gradually decreases, so that the high-speed airflow at the outlet of the tapered hole 31 forms a low-pressure area, which can enhance the suction of the cold air at the bottom, further increase the air inlet speed in the tapered hole 31, and form a high-efficiency circulation. Moreover, the hole wall of the tapered hole 31 can form a streamlined guide to the entering air for smooth acceleration, avoiding problems such as low flow rate, turbulence and "dead zone" that easily exist in ordinary straight holes.

[0050] Considering that when the flared end of the tapered hole 31 is arranged at the lower end surface of the epoxy resin package 3, the flared end of the tapered hole 31 is used as an air inlet and the small end is used as an air outlet, the flow speed of the airflow in the tapered hole 31 can be improved, and the active heat dissipation effect formed by the internal and external pressure difference can be more obvious. Therefore, in the embodiment of the present application, the flared end of the tapered hole 31 is arranged at the lower end surface of the epoxy resin package 3, that is, when the rectifier of the present application is installed on the circuit board, the lower end of the tapered hole 31 on the epoxy resin package 3 is large and used as an air inlet, and the upper end is small and used as an air outlet. It should be noted that this selection cannot be regarded as a limitation of the arrangement of the tapered hole 31 in the embodiment of the present application, but only as a more optimal choice, and another scheme can be selected in other embodiments.

[0051] Therefore, by arranging the two upper chips 21 and the two lower chips 22 in the vertical direction in the epoxy resin package 3, and arranging the two upper chips 21 and the two lower chips 22 symmetrically with respect to the axis of the tapered hole 31, the heat dissipation between the two diode chips 2 in the same layer is not interfered, and the heat dissipation between the two diode chips 2 on the same side is staggered, so that the heat dissipation space of each diode chip 2 has a very small interference area, which helps the diode chip 2 to dissipate heat by means of the upper patch 11 and the lower patch 12 and the epoxy resin package 3, and can improve the heat dissipation efficiency of the diode chip 2 in the effective volume space.

[0052] Moreover, by arranging the first protrusion 113 and the second protrusion 123 on the upper patch 11 and the lower patch 12, respectively, the welding of the diode chip 2 between the upper patch 11 and the lower patch 12 is more stable, and the situation of high-temperature de-welding can be effectively avoided. At the same time, the heat generated by each diode chip 2 during operation can be quickly transferred to the heat dissipation fin group at the tapered hole 31 in the middle of the epoxy resin package 3, and the heat can be dissipated through the air flowing in the tapered hole 31, and the heat dissipation efficiency is improved more obviously.

[0053] More importantly, when the air in the tapered hole 31 is heated by the heat pipe 5 and the heat dissipation fin group, the density decreases and naturally rises, and the external cold air enters from the bottom of the tapered hole 31 to supplement, forming a natural convection cycle; and due to the setting of the tapered hole 31 being small at the top and large at the bottom, the gas flow velocity at the top of the tapered hole 31 is large and the air pressure is low, which can enhance the suction force of the cold air at the bottom and promote the rapid outflow of hot air in the tapered hole 31, thereby improving the hot air exhaust efficiency and further promoting the heat dissipation effect of the heat dissipation fin group, forming a double heat dissipation effect composed of the temperature difference driven active heat dissipation and the passive heat dissipation of the heat pipe 5 and the heat dissipation fin group. And this way of driving gas flow by internal and external temperature difference is that the larger the temperature difference between the internal heat source temperature and the external environment temperature, the greater the effect of lifting the airflow, that is, the more heat the diode chip 2 generates when working, the greater the airflow speed in the tapered hole 31, and the better the above-mentioned double heat dissipation effect. The upper limit of the chip junction temperature of the diode chip 2 is generally 150°C, which provides sufficient conditions for this way of driving gas flow by internal and external temperature difference, and can ensure that the temperature difference driven active heat dissipation in the tapered hole 31 can operate stably.

[0054] Compared with ordinary straight holes, the tapered hole 31 in the epoxy resin package 3 of the present application has the advantages of high air flow resistance, low flow rate, easy formation of "dead zones", short air flow residence time, and the like, and its essence is still passive heat dissipation; the setting of the tapered hole 31 in the epoxy resin package 3 of the present application can enhance the suction force of the cold air at the bottom, improve the airflow speed in the tapered hole 31, and promote the rapid exhaust of hot air, forming a high-efficiency circulation to enhance the heat exchange effect between the cold air and the heat dissipation fin group, and the comprehensive heat dissipation efficiency can be improved by at least 35%.

[0055] Further, referring to Figure 4 、 Figure 5 and Figure 6The heat dissipation fin group comprises two annular integral fins 61 arranged axially along the tapered hole 31, the evaporation section of the heat pipe 5 corresponding to the lower chip 22 is located in the back recess of the corresponding first protrusion 113, the condensation section is connected with the annular integral fin 61 located above, the evaporation section of the heat pipe 5 corresponding to the upper chip 21 is located in the back recess of the corresponding second protrusion 123, and the condensation section is connected with the annular integral fin 61 located below; meanwhile, the first protrusion 113 and the second protrusion 123 both have an extension protrusion extending to the arc-shaped notch of the upper patch 11 and the lower patch 12 respectively, so that the heat pipe 5 is arranged without protruding from the surface of the upper patch 11 and the lower patch 12. And an insulating heat conduction layer is arranged between the contact part of the heat pipe 5 and the upper patch 11 and the lower patch 12 and / or between the contact part of the heat pipe 5 and the heat dissipation fin group, specifically, the insulating heat conduction layer is arranged between the combination part of the evaporation section of the heat pipe 5 and the upper patch 11 and the lower patch 12 and between the condensation section of the heat pipe 5 and the annular integral fin 61, the insulating heat conduction layer can be boron nitride ceramic coating, graphene film, aluminum oxide ceramic coating, etc., the thickness is controlled to be 10-20 μm, which can conduct heat and insulate, and low-temperature brazing material is used when welding the heat pipe 5 to avoid damaging the coating.

[0056] And, referring to Figure 3 and Figure 4 The condensation section of the heat pipe 5 has a semicircular arc part 51 matched with the annular integral fin 61, and the semicircular arc part 51 is located at the upper end surface of the annular integral fin 61 to reduce the influence of wind resistance; the annular integral fin 61 is arranged obliquely, and the inner edge end thereof is closest to the upper end surface of the epoxy resin package 3, specifically, the annular integral fin 61 is inclined upward along the direction of the airflow in the tapered hole 31.

[0057] Therefore, by embedding the heat pipe 5 in the back recess of the first protrusion 113, the back recess of the second protrusion 123 and the back recess of the extension protrusion, the heat pipe 5 can be arranged without protruding from the surface of the upper patch 11 and the lower patch 12, which greatly reduces the overall thickness of the upper patch 11, the lower patch 12 and the heat pipe 5, and is beneficial to the overall thickness control of the rectifier of the present application. Moreover, such arrangement is also beneficial to the gap control of the two annular integral fins 61, which ensures that the overall arrangement trend of the heat pipe 5 is horizontal and avoids breaking after welding at both ends. Meanwhile, by arranging the insulating heat conduction layer between the heat pipe 5 and the upper patch 11, the lower patch 12 and the annular integral fin 61, the heat conduction and heat dissipation effect of the heat pipe 5 can be ensured, and the short-circuit connection of the upper patch 11 and the lower patch 12 can be avoided.

[0058] Moreover, by setting the semicircular arc part 51, the contact area of the condenser section of the heat pipe 5 and the annular integrated fin 61 can be greatly increased, and the heat dissipation effect of the annular integrated fin 61 on the condenser section of the heat pipe 5 can be improved. Moreover, by setting the annular integrated fin 61 to be inclined, the smoothness of the airflow flowing in the tapered hole 31 can be improved, and the effective contact area of the annular integrated fin 61 with the flowing airflow can also be increased, so that the heat dissipation effect of the annular integrated fin 61 can be improved.

[0059] However, considering that the annular integrated fin 61 close to the air inlet of the tapered hole 31 contacts the cold air earlier, and has a larger outer diameter and can have a larger heat dissipation area, the cooling effect of the two diode chips 2 corresponding to the two annular integrated fins 61 can be different, which can cause the four diode chips 2 to work unstably or have a shortened service life.

[0060] Therefore, in one embodiment, the inclination angle of the annular integrated fin 61 close to the air inlet can be set to be greater than the inclination angle of the annular integrated fin 61 close to the air outlet, so as to reduce the interception effect of the annular integrated fin 61 close to the air inlet on the cold air entering from the air inlet of the tapered hole 31, and to minimize the difference in heat dissipation and cooling between the two annular integrated fins 61 and the two groups of heat pipes 5 corresponding to the two annular integrated fins 61.

[0061] In another embodiment, the materials of the two annular integrated fins 61 can also be different, for example, the material of the annular integrated fin 61 close to the air outlet is selected to be a high-thermal-conductivity composite material, such as aluminum-based graphene, and the material of the annular integrated fin 61 close to the air inlet is selected to be a conventional aluminum material, so as to balance the difference in heat dissipation and cooling by the difference in thermal conductivity coefficients of the two materials.

[0062] In another embodiment, the annular integrated fin 61 can also be set to be integrated by a plurality of ultra-thin fins, and the gap between the adjacent two ultra-thin fins in the annular integrated fin 61 close to the air outlet is small and the number of the ultra-thin fins is large, while the gap between the adjacent two ultra-thin fins in the annular integrated fin 61 close to the air inlet is large and the number of the ultra-thin fins is small, so as to also balance the difference in heat dissipation and cooling between the two.

[0063] Further, in order to improve the heat dissipation effect of the heat dissipation fin group of the present application, with reference to Figure 4 and Figure 6The heat dissipation fin group further comprises a plurality of split fins 62 arranged in an equidistant circumferential array along the axial direction of the tapered hole 31, and the plurality of split fins 62 are combined into an annular heat dissipation structure. The split fins 62 are arranged on one side of the annular integral fin 61 located below and close to the closed end of the tapered hole 31. A bimetallic strip 63 is fixed between the split fins 62 and the hole wall of the tapered hole 31. The bimetallic strip 63 is configured to flip the split fins 62 towards the annular integral fin 61 when the body temperature of the bimetallic strip 63 is greater than a set value, such as 100℃. A honeycomb copper mesh ring 64 is arranged on the hole wall of the tapered hole 31 between the bimetallic strip 63 and the adjacent annular integral fin 61.

[0064] Therefore, the annular heat dissipation structure composed of the plurality of split fins 62 can form a linear flow guide structure with the two annular integral fins 61 on the hole wall of the tapered hole 31, which can ensure smooth airflow in the tapered hole 31 as much as possible. The arrangement of the honeycomb copper mesh ring 64 can thermally connect the plurality of bimetallic strips 63 and the roots of the adjacent annular integral fins 61, so that the bimetallic strips 63 can monitor the temperature of the roots of the annular integral fins 61 in real time. Once the temperature of the roots of the annular integral fins 61 exceeds the preset value, the bimetallic strips 63 will bend upward, causing the split fins 62 on them to flip towards the annular integral fin 61, thereby increasing the inclination angle of the annular heat dissipation structure, reducing the airflow concentration at the inlet of the tapered hole 31, reducing the impact on the incoming airflow at the inlet of the tapered hole 31, and increasing the windward area of the annular integral fin 61 located below that is actually in contact with the airflow, thereby improving the overall heat dissipation effect of the two annular integral fins 61.

[0065] In order to ensure the air intake amount of the inlet of the tapered hole 31, with reference to Figure 4 and Figure 7 The lower end surface of the epoxy resin package 3 is fixed with a plurality of helical flow guide vanes 7 arranged in an equidistant circumferential array along the axial direction of the tapered hole 31. The helical flow guide vanes 7 are arranged along the radial direction of the tapered hole 31, and the side of the helical flow guide vanes 7 away from the epoxy resin package 3 is flush with the free end of the pin 4. Specifically, the helical angle of the helical flow guide vane 7 is 30°-45°, and four pieces are arranged to reduce the impact on the pressure drop and flow of the incoming airflow as much as possible.

[0066] Therefore, when the external air flows into the air inlet of the tapered hole 31 along the gap between the rectifier and the circuit board under the suction effect of the air inlet of the tapered hole 31, the airflow entering the air inlet of the tapered hole 31 is guided by the plurality of spiral flow guides 7 to form a spiral flow and accelerate the airflow speed. On the one hand, the spiral motion of the airflow after entering the tapered hole 31 can enhance the contact area between the airflow and the heat sink fin group, increase the contact time between the airflow and the heat sink fin group, improve the heat dissipation efficiency, and guide the airflow to flow along the axis direction of the tapered hole 31 to reduce lateral diffusion and accelerate natural convection by the pressure difference between the upper and lower ends of the tapered hole 31. On the other hand, the generation of spiral airflow can also eliminate airflow separation at the air inlet, avoid direct collision of cold and hot air, and reduce the formation of local vortex. Compared with the conventional straight hole arrangement, the airflow speed distribution uniformity can be improved. Therefore, the arrangement of the spiral flow guide 7 can form forced rotational flow and turbulence enhancement, which can significantly improve the heat dissipation uniformity and heat dissipation efficiency in the tapered hole 31, and is particularly suitable for high-power density electronic device heat dissipation scenarios with limited space.

[0067] In addition, considering that the typical thickness of the patch rectifier of the present application is only 1.4-1.6 mm, it is particularly noted that in assembling the present application, the upper patch 11, the lower patch 12 and the four diode chips 2 therein are first welded and fixed, and then the heat pipe 5 is welded on the upper patch 11 and the lower patch 12. After the heat pipe 5 is welded, the mold is positioned with the two annular integral fins 61, the plurality of split fins 62 and the plurality of bimetallic sheets 63. The outer wall of the mold fits the hole wall of the tapered hole 31, and then a layered packaging method is used to gradually form the epoxy resin packaging body 3. The outer edges of the annular integral fin 61 and the bimetallic sheet 63 need to be embedded in the epoxy resin packaging body 3 to a certain depth to meet the structural strength requirements. After the mold is removed, the honeycomb copper ring 64 is finally welded or bonded with thermal conductive glue. If necessary, the hole wall of the tapered hole 31 can be deburred.

[0068] Unless otherwise defined, the technical terms or scientific terms used in the present application should be understood as the usual meaning understood by a person with ordinary skills in the art to which the present application belongs. The "first", "second", "third" and similar words used in the specification and claims of the present application do not represent any order, quantity or importance, but are used to distinguish different components. "One" or "a" and similar words do not represent a quantity limitation, but represent the existence of at least one. "Include" or "contain" and similar words mean that the elements or objects appearing before "include" or "contain" cover the elements or objects listed after "include" or "contain" and their equivalents, and do not exclude other elements or objects. "Up", "down", "left", "right" and the like are only used to represent relative positional relationship, and when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0069] The above are all preferred embodiments of the present application, and do not limit the protection scope of the present application, so that: all equivalent changes made according to the structure, shape, principle of the present application should be covered within the protection scope of the present application.

Claims

1. A high-power thin-type patch bridge rectifier comprising an upper patch (11), a lower patch (12), four diode chips (2), an epoxy resin package (3), and four pins (4) protruding from the epoxy resin package (3), characterized in that, A conical hole (31) is formed in the middle of the epoxy resin package (3) and extends along the thickness direction of the epoxy resin package (3); four diode chips (2) are distributed in a diamond shape around the conical hole (31); A group of annular heat dissipation fins are mounted on the wall of the conical hole (31); four heat pipes (5) are arranged in the epoxy resin package (3); the evaporation section of the heat pipe (5) is in thermal connection with one of the diode chips (2), and the condensation section extends to be welded and fixed with the group of heat dissipation fins; The upper patch (11) includes a first upper copper patch (111) and a second upper copper patch (112) arranged in an insulating manner and corresponding to two diode chips (2) respectively; the lower patch (12) includes a first lower copper patch (121) and a second lower copper patch (122) arranged in an insulating manner and corresponding to two diode chips (2) respectively; The two diode chips (2) adjacent to the insulating parts of the first lower copper patch (121) and the second lower copper patch (122) correspond to the first upper copper patch (111); the two diode chips (2) adjacent to the other insulating parts of the first lower copper patch (121) and the second lower copper patch (122) correspond to the second upper copper patch (112); The first upper copper patch (111) and the second upper copper patch (112) are provided with first protrusions (113) downward corresponding to the parts of the opposite two diode chips (2); the first lower copper patch (121) and the second lower copper patch (122) are provided with second protrusions (123) upward corresponding to the parts of the other opposite two diode chips (2); The four diode chips (2) include upper chips (21) and lower chips (22) arranged in a staggered manner in the vertical direction; the upper chip (21) is located between the second protrusion (123) and the first upper copper patch (111) or the second upper copper patch (112); the lower chip (22) is located between the first protrusion (113) and the first lower copper patch (121) or the second lower copper patch (122); The group of heat dissipation fins includes two annular integral fins (61) arranged in an axial direction and spaced apart from each other; the evaporation section of the heat pipe (5) corresponding to the lower chip (22) is located in the back recess of the corresponding first protrusion (113), and the condensation section is connected with the annular integral fin (61) located above; the evaporation section of the heat pipe (5) corresponding to the upper chip (21) is located in the back recess of the corresponding second protrusion (123), and the condensation section is connected with the annular integral fin (61) located below.

2. A high power thin type patch bridge rectifier according to claim 1, characterized in that, The condensation section of the heat pipe (5) has a semicircular arc part (51) matched with the annular integral fin (61), and the semicircular arc part (51) is located at the upper end surface of the annular integral fin (61).

3. A high power thin type patch bridge rectifier according to claim 1, characterized in that, The annular integral fin (61) is arranged in an inclined manner, and the inner edge end thereof is closest to the upper end surface of the epoxy resin package (3).

4. The high power thin-type patch bridge rectifier of claim 1, wherein, The heat dissipation fin group further comprises a plurality of split fins (62) arranged in an equidistant circumferential array along the axial direction of the tapered hole (31), the split fins (62) being arranged on the side of the lower annular integral fin (61) close to the lower end surface of the epoxy resin package (3), a bimetallic strip (63) being fixed between the split fin (62) and the wall of the tapered hole (31), the bimetallic strip (63) being configured to drive the split fin (62) to flip in the direction close to the annular integral fin (61) when the body temperature of the bimetallic strip (63) is greater than a set value.

5. A high power thin type patch bridge rectifier according to claim 4, characterized in that, A honeycomb copper mesh ring (64) is arranged between the bimetallic strip (63) and the adjacent annular integral fin (61) on the wall of the tapered hole (31).

6. A high power thin type patch bridge rectifier according to claim 1, wherein A plurality of helical flow guide vanes (7) are fixed to the lower end surface of the epoxy resin package (3) and arranged in an equidistant circumferential array along the axial direction of the tapered hole (31), the helical flow guide vanes (7) being arranged along the radial direction of the tapered hole (31), the side of the helical flow guide vane (7) away from the epoxy resin package (3) being flush with the free end of the pin (4).

7. A high power thin type patch bridge rectifier as defined in claim 1, wherein An insulating heat-conducting layer is arranged between the contact part of the heat pipe (5) and the upper patch (11) and the lower patch (12) and / or between the contact part of the heat pipe (5) and the heat dissipation fin group.

Images