Bidirectional transient voltage suppressors

Abstract

The present invention discloses a bidirectional transient voltage suppressor device (TVS) comprising a first lead bar, a second lead bar, and two vertically stacked transient voltage suppressor (TVS) chips within an epoxy encapsulator. A first lead bar has one end connected to the lower end of a bent bar and its other end embedded in a notch at the bottom of the epoxy encapsulator. A second lead bar has one end electrically connected to the positive electrode of the TVS chip located at the bottom and its other end extends from the bottom surface of the epoxy encapsulator and is connected to a second lead bar. The second lead bar has a bent portion at its other end, and both the bent portion and the area of ​​the first lead bar near the side surface of the epoxy encapsulator are each formed with at least one through-hole. This invention improves the reliability of the device's electrical performance while maintaining the stability of the bonding force between the lead bar and the positive electrode of the TVS chip during use.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor devices, and in particular to a bidirectional transient voltage suppression device. Background Art

[0002] A diode is a commonly used semiconductor device. Its internal structure forms a PN junction composed of two semiconductors, P-type and N-type. Its primary characteristic is unidirectional conductivity, meaning current can only flow into the diode's positive terminal and out of its negative terminal. It is commonly used in circuits such as rectification, detection, and amplitude limiting. The time it takes for a switching diode to transition from cutoff (high-resistance state) to conduction (low-resistance state) is called turn-on time; the time it takes from conduction to cutoff is called reverse recovery time. The sum of these two times is called switching time. Diodes require excellent switching characteristics to be used in switching circuits. Summary of the Invention

[0003] The present invention aims to provide a bidirectional transient voltage suppressor device, which avoids cold solder joints and thus improves the reliability of the device's electrical performance while maintaining the stability of the bonding force between the lead bar and the positive electrode of the transient diode chip during use.

[0004] To achieve the above objectives, the present invention adopts a technical solution: a bidirectional transient voltage suppression device, comprising: a first lead bar, a second lead bar, and two vertically stacked transient diode chips within an epoxy package; a copper sheet is disposed between the cathode of the upper transient diode chip and the cathode of the lower transient diode chip; the copper sheet has a plurality of through holes formed therein at intervals; and two surfaces of the copper sheet are electrically connected to the positive and negative electrodes of adjacent transient diode chips, respectively, via a first solder layer;

[0005] One end of the first lead bar is electrically connected to the positive electrode of the transient diode chip located at the top, and the other end extends from the side of the epoxy encapsulation body and is connected to the upper end of the bending bar located outside the epoxy encapsulation body. One end of a first pin located between the epoxy encapsulation body and the bending bar is connected to the lower end of the bending bar, and the other end is embedded in the notch groove at the bottom of the epoxy encapsulation body.

[0006] One end of the second lead bar is electrically connected to the positive electrode of the transient diode chip at the bottom, and the other end extends from the bottom surface of the epoxy package and is connected to a second pin, and the first pin and the second pin are both flush with the bottom surface of the epoxy package;

[0007] The other end of the second lead bar is a bent portion, and the bent portion and the area of ​​the first lead bar close to the side surface of the epoxy package body are respectively provided with at least one through hole.

[0008] The further improved scheme in the above technical scheme is as follows:

[0009] 1. In the above solution, one end of the first lead bar is electrically connected to the positive electrode of the transient diode chip through the second solder layer.

[0010] 2. In the above solution, one end of the second lead bar is electrically connected to the positive electrode of the transient diode chip through the third solder layer.

[0011] 3. In the above solution, the shape of the through hole is circular, square or triangular.

[0012] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0013] 1. In the bidirectional transient voltage suppressor device of the present invention, a copper sheet is disposed between the cathode of an upper transient diode chip and the cathode of a lower transient diode chip. The copper sheet has a plurality of through holes formed at intervals. The two surfaces of the copper sheet are electrically connected to the positive and negative electrodes of adjacent transient diode chips, respectively, via a first solder layer. This effectively alleviates the defect that multiple transient diode chips are prone to shifting or warping when stacked vertically. The transient diode chips and the copper sheet can be maintained in parallel, preventing solder joint defects and thereby improving the reliability of the device's electrical performance.

[0014] 2. In the bidirectional transient voltage suppressor device of the present invention, the other end of the second lead bar is a bent portion, and the bent portion and the area of ​​the first lead bar near the side surface of the epoxy package body are respectively provided with at least one through hole, thereby maintaining the stability of the bonding force between the lead bar and the positive electrode of the transient diode chip during use, thereby improving the overall strength of the device; in addition, the other end of the first lead bar extends from the side of the epoxy package body and is connected to the upper end of the bent bar located outside the epoxy package body, and a first pin located between the epoxy package body and the bent bar has one end connected to the lower end of the bent bar and the other end embedded in the notch groove at the bottom of the epoxy package body, thereby reducing the probability of water vapor entering the interior of the device, thereby extending the service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Attachment Figure 1 Schematic diagram of the structure of the bidirectional transient voltage suppression device of the present invention.

[0016] In the above figures: 1. Epoxy package; 2. First lead bar; 3. Second lead bar; 4. Transient diode chip; 5. Bend bar; 6. First pin; 7. Second pin; 8. Copper sheet; 9. Through hole; 10. First solder layer; 11. Second solder layer; 12. Third solder layer; 13. Through hole; 14. Bend portion; 15. Notch. DETAILED DESCRIPTION

[0017] Example 1: A bidirectional transient voltage suppression device, comprising: a first lead bar 2, a second lead bar 3, and two vertically stacked transient diode chips 4 within an epoxy package 1. A copper sheet 8 is disposed between the cathode of the upper transient diode chip 4 and the cathode of the lower transient diode chip 4. The copper sheet 8 has a plurality of through holes 9 formed therein at intervals. The two surfaces of the copper sheet 8 are electrically connected to the positive and negative electrodes of the adjacent transient diode chips 4, respectively, via a first solder layer 10.

[0018] One end of the first lead bar 2 is electrically connected to the positive electrode of the transient diode chip 4 located at the top, and the other end extends from the side of the epoxy encapsulation body 1 and is connected to the upper end of the bending bar 5 located outside the epoxy encapsulation body 1. A first pin 6 located between the epoxy encapsulation body 1 and the bending bar 5 has one end connected to the lower end of the bending bar 5 and the other end embedded in the notch 15 at the bottom of the epoxy encapsulation body 1;

[0019] One end of the second lead bar 3 is electrically connected to the positive electrode of the transient diode chip 4 located at the bottom, and the other end extends from the bottom surface of the epoxy package 1 and is connected to a second pin 7. The first pin 6 and the second pin 7 are both flush with the bottom surface of the epoxy package 1;

[0020] The other end of the second lead bar 3 is a bent portion 14 . The bent portion 8 and the area of ​​the first lead bar 2 close to the side surface of the epoxy package 1 are each formed with at least one through hole 13 .

[0021] The through hole 9 is in a square or triangle shape.

[0022] Example 2: A bidirectional transient voltage suppression device, comprising: a first lead bar 2, a second lead bar 3, and two vertically stacked transient diode chips 4 within an epoxy package 1. A copper sheet 8 is disposed between the cathode of the upper transient diode chip 4 and the cathode of the lower transient diode chip 4. The copper sheet 8 has a plurality of through holes 9 formed therein at intervals. The two surfaces of the copper sheet 8 are electrically connected to the positive and negative electrodes of the adjacent transient diode chips 4, respectively, via a first solder layer 10.

[0023] One end of the first lead bar 2 is electrically connected to the positive electrode of the transient diode chip 4 located at the top, and the other end extends from the side of the epoxy encapsulation body 1 and is connected to the upper end of the bending bar 5 located outside the epoxy encapsulation body 1. A first pin 6 located between the epoxy encapsulation body 1 and the bending bar 5 has one end connected to the lower end of the bending bar 5 and the other end embedded in the notch 15 at the bottom of the epoxy encapsulation body 1;

[0024] One end of the second lead bar 3 is electrically connected to the positive electrode of the transient diode chip 4 located at the bottom, and the other end extends from the bottom surface of the epoxy package 1 and is connected to a second pin 7. The first pin 6 and the second pin 7 are both flush with the bottom surface of the epoxy package 1;

[0025] The other end of the second lead bar 3 is a bent portion 14 . The bent portion 8 and the area of ​​the first lead bar 2 close to the side surface of the epoxy package 1 are each formed with at least one through hole 13 .

[0026] One end of the first lead bar 2 is electrically connected to the anode of the transient diode chip 4 via the second solder layer 11 .

[0027] One end of the second lead bar 3 is electrically connected to the anode of the transient diode chip 4 via the third solder layer 12 .

[0028] The through hole 9 is in a triangular shape.

[0029] When using the above-mentioned bidirectional transient voltage suppressor device, it effectively improves the defect that multiple transient diode chips are easily offset or warped when stacked in the vertical direction, so that the transient diode chips and the copper sheet can be arranged in parallel, avoiding poor solder joints and thus improving the reliability of the device's electrical performance. In addition, the other end of the second lead bar is a bent portion, and the bent portion and the area of ​​the first lead bar near the side surface of the epoxy package body are each formed with at least one through hole. This maintains the stability of the bonding force between the lead bar and the positive electrode of the transient diode chip during use, thereby improving the overall strength of the device. In addition, the probability of water vapor entering the interior of the device is reduced, thereby extending the service life.

[0030] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A bidirectional transient voltage suppressor device, characterized in that: include: A first lead strip (2), a second lead strip (3) and two transient diode chips (4) stacked in a vertical direction are located in an epoxy package (1); a copper sheet (8) is provided between the cathode of the upper transient diode chip (4) and the cathode of the lower transient diode chip (4); a plurality of through holes (9) are provided on the copper sheet (8) at intervals; two surfaces of the copper sheet (8) are electrically connected to the anode and cathode of the adjacent transient diode chips (4) through a first solder layer (10); One end of the first lead bar (2) is electrically connected to the positive electrode of the transient diode chip (4) located at the top, and the other end extends from the side of the epoxy package (1) and is connected to the upper end of the bending bar (5) located outside the epoxy package (1); one end of a first pin (6) located between the epoxy package (1) and the bending bar (5) is connected to the lower end of the bending bar (5), and the other end is embedded in the notch groove (15) at the bottom of the epoxy package (1); One end of the second lead bar (3) is electrically connected to the positive electrode of the transient diode chip (4) located at the bottom, and the other end extends from the bottom surface of the epoxy package (1) and is connected to a second pin (7), and the first pin (6) and the second pin (7) are both flush with the bottom surface of the epoxy package (1); The other end of the second lead bar (3) is a bent portion (14), and the bent portion (14) and the area of ​​the first lead bar (2) close to the side surface of the epoxy package (1) are each provided with at least one through hole (13); One end of the first lead bar (2) is electrically connected to the positive electrode of the transient diode chip (4) via a second solder layer (11); and one end of the second lead bar (3) is electrically connected to the positive electrode of the transient diode chip (4) via a third solder layer (12).

2. The bidirectional transient voltage suppression device according to claim 1, wherein: The outer surfaces of the first pin (6) and the second pin (7) are each plated with a zinc layer.

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