A low-stress high-current bridge rectifier
By using flexible circuit boards and precision wiring to optimize the current path, the problem of silicon chip cracking and desoldering caused by the difference in thermal expansion coefficients in bridge rectifiers was solved, improving device reliability and electrical efficiency, and achieving miniaturization and simplified production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- DONGGUAN NEWAIR ELECTRONICS CO LTD
- Filing Date
- 2025-06-25
- Publication Date
- 2026-06-19
AI Technical Summary
In bridge rectifiers, copper sheets are soldered to the anode and cathode of the silicon chip. The large difference in thermal expansion coefficients between copper and silicon causes mechanical stress caused by temperature fluctuations under high current conditions, which can lead to silicon chip breakage or electrode detachment.
Flexible circuit boards are used to replace traditional rigid copper sheets as the connection carrier for chip electrodes and the internal circuit connection medium. Flexible circuit boards made of polyimide material have excellent flexibility and low bending stiffness, absorb and buffer stress, and optimize the current path through precision wiring.
It effectively solves the problems of chip stress cracking and desoldering caused by mismatch in thermal expansion coefficients, improves the reliability and lifespan of devices, reduces parasitic parameters, improves electrical efficiency, and facilitates miniaturization and simplified production.
Smart Images
Figure CN224385785U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of semiconductor devices, and more specifically, to a low-stress, high-current bridge rectifier. Background Technology
[0002] A bridge rectifier is a commonly used circuit that converts alternating current (AC) to direct current (DC). Its core structure consists of four diodes connected in a specific way to form a "bridge" topology.
[0003] In related technologies, bridge rectifiers typically include four silicon chips. Each silicon chip has copper sheets welded to its anode and cathode to form a diode structure. The four diode structures are encapsulated in a package. Using the above-mentioned technologies, the thermal expansion coefficients of copper and silicon differ greatly. Under high current conditions, temperature fluctuations can easily cause deformation of the copper sheets, generating mechanical stress that can cause the silicon chips to crack or the electrodes to detach. Utility Model Content
[0004] To address the problem in related technologies where copper sheets are welded to both the anode and cathode of a silicon chip to form a diode structure, and the large difference in thermal expansion coefficients between copper and silicon, temperature fluctuations under high current conditions can easily cause deformation of the copper sheets, generating mechanical stress that can lead to silicon chip breakage or electrode detachment, this application provides a low-stress, high-current bridge rectifier.
[0005] A low-stress, high-current bridge rectifier includes a first silicon chip, a second silicon chip, a third silicon chip, a fourth silicon chip, a bottom flexible circuit board, a first top flexible circuit board, a second top flexible circuit board, a DC positive pin, a DC negative pin, an AC positive pin, an AC negative pin, and a base plate. The bottom flexible circuit board is laid flat and fixed on the base plate. The bottom flexible circuit board has a first pad, a second pad, a third pad, and a fourth pad arranged in a square. The cathode of the first silicon chip is soldered to the first pad via solder. The anode of the second silicon chip is soldered to the second pad via solder. The cathode of the third silicon chip is soldered to the third pad via solder. The anode of the fourth silicon chip is soldered to the fourth pad via solder. A fifth pad is disposed between the first and second pads on the bottom flexible circuit board. A sixth pad is disposed between the third and fourth pads on the bottom flexible circuit board. A first connection circuit and a second connection circuit are disposed between the layers of the bottom flexible circuit board. The first, second, and fifth pads are electrically connected through the first connection circuit. The third... The first, fourth, and sixth pads are electrically connected via a second connection circuit. The AC positive pin is connected to the fifth pad via a bonding wire, and the AC negative pin is connected to the sixth pad via a bonding wire. The first top flexible circuit board is provided with a seventh, eighth, and ninth pad. The anode of the first silicon chip is soldered to the seventh pad via solder, and the anode of the third silicon chip is soldered to the eighth pad via solder. A third connection circuit is provided between the layers of the first top flexible circuit board, and the seventh, eighth, and ninth pads are connected via... The DC positive terminal pin is electrically connected to the ninth pad via a third circuit. The second top flexible circuit board is provided with a tenth pad, an eleventh pad, and a twelfth pad. The cathode of the second silicon chip is soldered to the tenth pad via solder. The cathode of the fourth silicon chip is soldered to the eleventh pad via solder. A fourth connection circuit is provided between the layers of the second top flexible circuit board. The tenth pad, the eleventh pad, and the twelfth pad are electrically connected via the fourth connection circuit. The DC negative terminal pin is connected to the twelfth pad via a bonding wire.
[0006] Preferably, the substrate of the bottom flexible circuit board, the first top flexible circuit board, and the second top flexible circuit board is polyimide, and its elastic modulus is ≤3.5GPa2.
[0007] Preferably, the DC positive pin, DC negative pin, AC positive pin, and AC negative pin are all fixed to the substrate by an adhesive layer.
[0008] Preferably, the DC positive pin, DC negative pin, AC positive pin, and AC negative pin are all copper sheets.
[0009] Preferably, the bonding wire is a copper wire.
[0010] Preferably, the solder is solder paste.
[0011] Preferably, the PN junction depletion regions of the first silicon chip, the second silicon chip, the third silicon chip, and the fourth silicon chip extend directly to the chip surface.
[0012] Preferably, the package further includes a package body comprising a plastic shell and epoxy resin. The plastic shell covers a first silicon chip, a second silicon chip, a third silicon chip, a fourth silicon chip, a bottom flexible circuit board, a first top flexible circuit board, a second top flexible circuit board, a DC positive pin, a DC negative pin, an AC positive pin, an AC negative pin, and a bottom substrate. The DC positive pin, DC negative pin, AC positive pin, AC negative pin, and bottom substrate partially extend outside the plastic shell, and the epoxy resin fills the interior of the plastic shell.
[0013] The beneficial technical effects of this application are as follows: Using a flexible circuit board instead of a traditional rigid copper sheet as the connection carrier for chip electrodes and the internal circuit connection medium, the flexible circuit board has excellent flexibility and low bending stiffness, effectively absorbing and buffering stress. This solves the problem of chip stress cracking and desoldering failure caused by thermal expansion coefficient mismatch under high current conditions, significantly improving the reliability and lifespan of the device. Simultaneously, the precise wiring integrated by the FPC optimizes the current path, reduces parasitic parameters, and improves electrical efficiency; its compact structure facilitates miniaturization and simplifies production. Attached Figure Description
[0014] Figure 1 This is a schematic diagram of the overall structure of a low-stress, high-current bridge rectifier according to this embodiment.
[0015] Figure 2 This is a schematic diagram of the internal structure of a low-stress, high-current bridge rectifier according to this embodiment.
[0016] Figure 3 This is a schematic diagram of the structure of the first top flexible circuit board in this embodiment.
[0017] Figure 4 This is a schematic diagram of the structure of the second top flexible circuit board in this embodiment.
[0018] Reference numerals: 1. First silicon chip; 2. Second silicon chip; 3. Third silicon chip; 4. Fourth silicon chip; 5. Bottom flexible circuit board; 6. First top flexible circuit board; 7. Second top flexible circuit board; 8. DC positive pin; 9. DC negative pin; 10. AC positive pin; 11. AC negative pin; 12. Substrate; 13. Package; 14. First pad; 15. Second pad; 16. Third pad; 17. Fourth pad; 18. Fifth pad; 19. Sixth pad; 20. Bonding wire; 21. Seventh pad; 22. Eighth pad; 23. Ninth pad; 24. Tenth pad; 25. Eleventh pad; 26. Twelfth pad; Detailed Implementation
[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0020] Reference Figure 1 and Figure 2 A low-stress, high-current bridge rectifier comprises a first silicon chip 1, a second silicon chip 2, a third silicon chip 3, a fourth silicon chip 4, a bottom flexible circuit board 5, a first top flexible circuit board 6, a second top flexible circuit board 7, a DC positive pin 8, a DC negative pin 9, an AC positive pin 10, an AC negative pin 11, a base plate 12, and a package 13. The bottom flexible circuit board 5 is laid flat and fixed on the base plate 12 and is fixed to the base plate 12 with high-temperature resistant epoxy resin. The bottom flexible circuit board 5 is provided with a first pad 14, a second pad 15, a third pad 16, and a fourth pad 17 arranged in a square. The cathode of the first silicon chip 1 is soldered to the first pad 14, the anode of the second silicon chip 2 is soldered to the second pad 15, the cathode of the third silicon chip 3 is soldered to the third pad 16, and the anode of the fourth silicon chip 4 is soldered to the fourth pad 17.
[0021] The bottom flexible circuit board 5 has a fifth pad 18 between the first pad 14 and the second pad 15, and a sixth pad 19 between the third pad 16 and the fourth pad 17. The bottom flexible circuit board 5 has a first connection circuit and a second connection circuit between its layers. The first pad 14, the second pad 15, and the fifth pad 18 are electrically connected through the first connection circuit. The AC positive pin 10 is connected to the fifth pad 18 through a bonding wire 20, and the AC negative pin 11 is connected to the sixth pad 19 through a bonding wire 20.
[0022] The first top flexible circuit board 6 is provided with a seventh pad 21, an eighth pad 22, and a ninth pad 23. The anode of the first silicon chip 1 is soldered to the seventh pad 21 through solder, and the anode of the third silicon chip 3 is soldered to the eighth pad 22 through solder. A third connection circuit is provided between the layers of the first top flexible circuit board 6. The ninth pad 23 is located between the seventh pad 21 and the eighth pad 22, and the seventh pad 21, the eighth pad 22, and the ninth pad 23 are electrically connected through the third circuit. The DC positive pin 8 is connected to the ninth pad 23 through a bonding wire 20.
[0023] The second top flexible circuit board 7 is provided with a tenth pad 24, an eleventh pad 25, and a twelfth pad 26. The cathode of the second silicon chip 2 is soldered to the tenth pad 24, and the cathode of the fourth silicon chip 4 is soldered to the eleventh pad 25. A fourth connection circuit is provided between the layers of the second top flexible circuit board 7. The twelfth pad 26 is located between the tenth pad 24 and the eleventh pad 25, and the tenth pad 24, the eleventh pad 25, and the twelfth pad 26 are electrically connected through the fourth connection circuit. The DC negative terminal pin 9 is connected to the twelfth pad 26 through a bonding wire 20.
[0024] In the aforementioned structure, a flexible circuit board (FPC) replaces the traditional rigid copper sheet as the connection carrier for chip electrodes and the internal circuit connection medium. The FPC's excellent flexibility and low bending stiffness effectively absorb and buffer stress, solving the problem of chip stress cracking and desoldering failure caused by thermal expansion coefficient mismatch under high current conditions, significantly improving device reliability and lifespan. Simultaneously, the precise wiring integrated by the FPC optimizes the current path, reduces parasitic parameters, and improves electrical efficiency; its compact structure facilitates miniaturization and simplified production.
[0025] Furthermore, the substrate 12 is made of ceramic substrate, which has good heat dissipation effect and facilitates heat dissipation for flexible circuit boards and silicon chips.
[0026] Furthermore, the substrates of the bottom flexible circuit board 5, the first top flexible circuit board 6, and the second top flexible circuit board 7 are polyimide with an elastic modulus ≤3.5GPa2. The low elastic modulus of polyimide causes the flexible circuit board to undergo micro-bending deformation during thermal expansion, which effectively avoids stress transmission to the silicon chip.
[0027] Furthermore, the DC positive pin 8, DC negative pin 9, AC positive pin 10, and AC negative pin 11 are all fixed to the base plate 12 by an adhesive layer, so that the pins are rigidly supported. The adhesive layer is high-temperature resistant epoxy resin, and the DC positive pin 8, DC negative pin 9, AC positive pin 10, and AC negative pin 11 are all copper sheets with good conductivity.
[0028] Furthermore, the bonding wire 20 is a copper wire.
[0029] Furthermore, the solder is solder paste, and the soldering method used is reflow soldering.
[0030] Furthermore, the PN junction depletion regions of the first silicon chip 1, the second silicon chip 2, the third silicon chip 3, and the fourth silicon chip extend directly to the chip surface, which allows the chip to carry a larger current.
[0031] Furthermore, the package 13 includes a plastic shell and epoxy resin. The plastic shell covers the first silicon chip 1, the second silicon chip 2, the third silicon chip 3, the fourth silicon chip 4, the bottom flexible circuit board 5, the first top flexible circuit board 6, the second top flexible circuit board 7, the DC positive pin 8, the DC negative pin 9, the AC positive pin 10, the AC negative pin 11, and the base plate 12. The DC positive pin 8, the DC negative pin 9, the AC positive pin 10, the AC negative pin 11, and the base plate 12 extend outside the plastic shell. The epoxy resin fills the inside of the plastic shell. The combination of plastic and epoxy resin is used to encapsulate the chips, flexible circuit boards, and pins, reducing the damage to the chips and flexible circuit boards caused by external environmental influences. The epoxy resin filling provides good heat dissipation.
[0032] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A low-stress, high-current bridge rectifier, characterized in that: The system includes a first silicon chip, a second silicon chip, a third silicon chip, a fourth silicon chip, a bottom flexible circuit board, a first top flexible circuit board, a second top flexible circuit board, a DC positive terminal pin, a DC negative terminal pin, an AC positive terminal pin, an AC negative terminal pin, and a base substrate. The bottom flexible circuit board is laid flat and fixed on the base substrate. The bottom flexible circuit board has a first pad, a second pad, a third pad, and a fourth pad arranged in a square. The cathode of the first silicon chip is soldered to the first pad, the anode of the second silicon chip is soldered to the second pad, the cathode of the third silicon chip is soldered to the third pad, and the anode of the fourth silicon chip is soldered to the fourth pad. A fifth pad is provided between the first and second pads on the bottom flexible circuit board, and a sixth pad is provided between the third and fourth pads. A first connection circuit and a second connection circuit are provided between the layers of the bottom flexible circuit board. The first, second, and fifth pads are electrically connected through the first connection circuit, and the third and fourth pads are... The sixth pad is electrically connected via a second connection circuit. The positive AC pin is connected to the fifth pad via a bonding wire, and the negative AC pin is connected to the sixth pad via a bonding wire. The first top flexible circuit board is provided with a seventh, eighth, and ninth pad. The anode of the first silicon chip is soldered to the seventh pad via solder, and the anode of the third silicon chip is soldered to the eighth pad via solder. A third connection circuit is provided between the layers of the first top flexible circuit board, and the seventh, eighth, and ninth pads are connected via the third circuit. The circuit is electrically connected, with the DC positive pin connected to the ninth pad via a bonding wire. The second top flexible circuit board is provided with a tenth pad, an eleventh pad, and a twelfth pad. The cathode of the second silicon chip is soldered to the tenth pad via solder, and the cathode of the fourth silicon chip is soldered to the eleventh pad via solder. A fourth connection circuit is provided between the layers of the second top flexible circuit board, and the tenth, eleventh, and twelfth pads are electrically connected via the fourth connection circuit. The DC negative pin is connected to the twelfth pad via a bonding wire.
2. The low-stress, high-current bridge rectifier according to claim 1, characterized in that: The substrate of the bottom flexible circuit board, the first top flexible circuit board, and the second top flexible circuit board is polyimide, and its elastic modulus is ≤3.5GPa2.
3. The low-stress, high-current bridge rectifier according to claim 1, characterized in that: The DC positive pin, DC negative pin, AC positive pin, and AC negative pin are all fixed to the substrate by an adhesive layer.
4. A low-stress, high-current bridge rectifier according to claim 3, characterized in that: The DC positive pin, DC negative pin, AC positive pin, and AC negative pin are all made of copper.
5. A low-stress, high-current bridge rectifier according to claim 4, characterized in that: The bonding wire is copper wire.
6. A low-stress, high-current bridge rectifier according to claim 1, characterized in that: The solder is solder paste.
7. A low-stress, high-current bridge rectifier according to claim 1, characterized in that: The PN junction depletion regions of the first silicon chip, the second silicon chip, the third silicon chip, and the fourth silicon chip extend directly to the chip surface.
8. A low-stress, high-current bridge rectifier according to claim 1, characterized in that: It also includes a package, which comprises a plastic shell and epoxy resin. The plastic shell covers a first silicon chip, a second silicon chip, a third silicon chip, a fourth silicon chip, a bottom flexible circuit board, a first top flexible circuit board, a second top flexible circuit board, a DC positive pin, a DC negative pin, an AC positive pin, an AC negative pin, and a bottom substrate. The DC positive pin, DC negative pin, AC positive pin, AC negative pin, and bottom substrate partially extend outside the plastic shell, and the epoxy resin fills the interior of the plastic shell.