Zero-crossing prevention thyristor

Abstract

The application relates to a zero-crossing oscillation prevention thyristor, which comprises a thyristor chip, a bidirectional trigger diode chip, a heat dissipation substrate, first to third pins and a package. The top layer of the heat dissipation substrate is provided with independent first and second solder pads; the MT1 terminal of the thyristor chip is soldered to the first solder pad, and the bottom surface electrode of the bidirectional trigger diode chip is soldered to the second solder pad; the top surface electrode is connected to the thyristor gate through a first bonding wire; the second solder pad is connected to the first pin through a second bonding wire; the MT2 terminal of the thyristor is connected to the second pin through a third bonding wire; the third pin is soldered to the first solder pad; and all the elements are integrated and packaged by the package. The application has the effect of preventing zero-crossing oscillation, low cost and high energy effect.

Description

Technical Field

[0001] This application relates to the field of semiconductor devices, and more specifically, to a thyristor that is protected against zero-crossing oscillation. Background Technology

[0002] As a high-power semiconductor switching device, the thyristor is widely used in AC voltage regulation, motor control, solid-state relays, lighting dimming, and power switching. It controls the conduction angle through a gate trigger signal to achieve phase control of AC power, and has advantages such as low cost, high voltage withstand capability, and large current carrying capacity.

[0003] Zero-crossing oscillation refers to the high-frequency damped oscillation that easily forms when the reverse electromotive force generated by the inductive load is superimposed on the power supply voltage near the zero-crossing point of the AC current. Zero-crossing oscillation can easily cause instantaneous changes in the voltage waveform near the zero-crossing point. If the thyristor is in the critical state of being turned off at this time, the oscillating voltage may cause the following serious problems: 1. Exceeding the device's critical value, causing the thyristor to self-conduct without a gate signal, thus destroying the phase control logic; 2. Repeated unexpected switching on and off causes load current oscillation, resulting in equipment jitter, noise, and abnormal temperature rise; 3. Repeated surge currents accelerate device aging and may even break down the silicon wafer structure.

[0004] In related technologies, embedded RC snubber circuits are commonly used to suppress zero-crossing oscillations. However, this technology has drawbacks such as increased system size and cost, and continuous heating of the resistor reducing energy efficiency. Therefore, it is necessary to design a low-cost, high-efficiency thyristor to suppress zero-crossing oscillations. Utility Model Content

[0005] In order to address the problem that in related technologies, thyristors use embedded RC buffer circuits to suppress zero-crossing oscillations, which increases system size and cost and causes continuous heating of resistors, thus reducing energy efficiency, this application provides a thyristor that prevents zero-crossing oscillations.

[0006] A zero-crossing oscillation-resistant thyristor includes a thyristor chip, a bidirectional trigger diode chip, a heat dissipation substrate, a first pin, a second pin, a third pin, and a package. The top layer of the heat dissipation substrate has independent first and second pads. The MT1 terminal of the thyristor chip is soldered to the first pad. The bottom electrode of the bidirectional trigger diode chip is soldered to the second pad. The top electrode of the bidirectional trigger diode chip is connected to the gate terminal of the thyristor chip via a first bonding wire. The second pad is connected to the first pin via a second bonding wire. The MT2 terminal of the thyristor chip is connected to the second pin via a third bonding wire. The third pin is soldered to the first pad. The package covers the thyristor chip, the bidirectional trigger diode chip, the heat dissipation substrate, the first bonding wire, the second bonding wire, and the third bonding wire.

[0007] Preferably, the heat dissipation substrate is a copper-clad ceramic substrate or an insulating metal substrate.

[0008] Preferably, the first bonding wire, the second bonding wire, and the third bonding wire are aluminum wires.

[0009] Preferably, the solder is solder paste.

[0010] Preferably, the package includes a plastic shell and epoxy resin. The plastic shell covers the thyristor chip, the bidirectional trigger diode chip, the heat dissipation substrate, the first bonding wire, the second bonding wire, and the third bonding wire. One end of the first pin, the second pin, and the third pin is placed inside the plastic shell, and the other end of the first pin, the second pin, and the third pin is placed outside the plastic shell. The epoxy resin fills the interior of the plastic shell.

[0011] Preferably, the thyristor chip is a unidirectional thyristor chip.

[0012] Preferably, the bidirectional trigger diode chip has a five-layer symmetrical structure.

[0013] The beneficial technical effects of this application are as follows: By integrating a bidirectional trigger diode chip within the package, the bidirectional trigger diode chip sets a high trigger threshold through its precise and symmetrical break-off voltage. It maintains absolute off-state in the low-voltage region where the AC voltage crosses zero, completely cutting off any current path flowing to the gate of the thyristor, thereby fundamentally preventing false triggering near the zero-crossing point caused by minor noise or voltage. Simultaneously, its negative resistance characteristic and low holding current ensure that the trigger signal is a short pulse, and the gate current is quickly cut off after triggering. These two characteristics work together to ensure that the thyristor is only triggered when the AC voltage rises sufficiently and the load current can reliably maintain its conduction, effectively eliminating zero-crossing oscillation and ensuring stable and reliable operation of the thyristor in AC circuits. This structure eliminates dependence on external RC components, directly reducing resistors, capacitors, and PCB mounting space, lowering overall material costs and circuit board layout complexity. The integrated design makes the application circuit more compact, and it avoids the continuous conduction loss of resistors in traditional solutions, reducing system standby power consumption and improving energy efficiency. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of a thyristor that prevents zero-crossing oscillation in this embodiment.

[0015] Figure 2 This is a schematic diagram of the internal structure of a thyristor that prevents zero-crossing oscillation in this embodiment.

[0016] Figure 3 This is a schematic diagram of the structure of the thyristor chip in this embodiment.

[0017] Figure 4 This is a schematic diagram of the bidirectional trigger diode chip in this embodiment.

[0018] Reference numerals: 1. Thyristor chip; 11. MT1 terminal; 12. MT2 terminal; 13. Gate terminal; 14. Outer P layer; 15. Outer N layer; 16. Middle P layer; 17. Middle N layer; 2. Bidirectional trigger diode chip; 21. First N+ type heavily doped silicon layer; 22. First P type silicon layer; 23. N type lightly doped silicon layer; 24. Second P type silicon layer; 25. Second N+ type heavily doped silicon layer; 3. Heat dissipation substrate; 31. First pad; 32. Second pad; 4. First pin; 5. Second pin; 6. Third pin; 7. Package; 71. Plastic shell; 8. First bonding wire; 9. Second bonding wire; 10. Third bonding wire. 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 1-4A thyristor with zero-crossing oscillation protection includes a thyristor chip 1, a bidirectional trigger diode chip 2, a heat dissipation substrate 3, a first pin 4, a second pin 5, a third pin 6, and a package 7. The thyristor chip 1 is a unidirectional thyristor, which adopts a standard four-layer three-terminal semiconductor structure, including an MT1 terminal 11, an MT2 terminal 12, a gate terminal 13, an outer P layer, an outer N layer, a middle P layer 16, and a middle N layer 17. The MT1 terminal 11 is connected to the outermost P layer 14, the MT2 terminal 12 is connected to the outermost N layer 15, and the gate terminal 13 is connected to the middle P layer 16. The bidirectional trigger diode chip has a five-layer symmetrical structure, which, from top to bottom, consists of a first N+ type heavily doped silicon layer 21, a first P type silicon layer 22, an N type lightly doped silicon layer 23, a second P type silicon layer 24, and a second N+ type heavily doped silicon layer 25. The top surface of the thyristor chip 1 is the top electrode, and the bottom surface of the second N+ type heavily doped silicon layer 24 is the bottom electrode. The top layer of the heat dissipation substrate 3 is provided with independent first pad 31 and second pad 32. The MT1 terminal 11 of the thyristor chip 1 is soldered to the first pad 31. The bottom electrode of the bidirectional trigger diode chip 2 is soldered to the second pad 32. The top electrode of the bidirectional trigger diode chip 2 is connected to the gate terminal 13 of the thyristor chip 1 through the first bonding wire 8. The second pad 32 is connected to the first pin 4 through the second bonding wire 9. The MT2 terminal 12 of the thyristor chip 1 is connected to the second pin 5 through the third bonding wire 10. The third pin 6 is soldered to the first pad 31. The package 7 covers the thyristor chip 1, the bidirectional trigger diode chip 2, the heat dissipation substrate 3, the first bonding wire 8, the second bonding wire 9, and the third bonding wire 10. In the above structure, a bidirectional trigger diode chip is integrated into the thyristor. The high-precision breakover voltage of the bidirectional trigger diode chip creates a trigger threshold in the low-voltage region near the AC zero-crossing point, completely blocking stray current paths flowing to the gate of the thyristor and eliminating false triggering caused by oscillating voltage. Furthermore, the negative resistance characteristic of the bidirectional trigger diode chip ensures that the trigger signal is a short pulse. After triggering, the gate current is automatically cut off, so that the thyristor is only triggered in the range where the AC voltage rises to reliably maintain conduction. Compared with existing technologies, it eliminates the need for an external RC snubber circuit, directly reducing resistors, capacitors, and PCB space, reducing material costs and layout complexity, eliminating the continuous conduction loss of resistors in traditional RC circuits, reducing system standby power consumption, and improving energy efficiency.

[0021] Reference Figure 2 Furthermore, the heat dissipation substrate 3 is a copper-clad ceramic substrate or an insulating metal substrate, preferably a copper-clad ceramic substrate. The copper-clad ceramic substrate has excellent heat dissipation performance, which facilitates heat dissipation of the device and enhances its service life.

[0022] Reference Figure 2 Furthermore, the first bonding wire 8, the second bonding wire 9, and the third bonding wire 10 are aluminum wires. Aluminum wires have excellent conductivity, which helps to reduce losses.

[0023] Furthermore, the solder is solder paste, which is simple to operate and low in cost.

[0024] Reference Figure 1 and Figure 2 Furthermore, the package 7 includes a plastic shell 71 and epoxy resin. The plastic shell 71 covers the silicon controlled rectifier chip 1, the bidirectional trigger diode chip 2, the heat dissipation substrate 3, the first bonding wire 8, the second bonding wire 9, and the third bonding wire 10. One end of the first pin 4, the second pin 5, and the third pin 6 is placed inside the plastic shell 71, and the other end of the first pin 4, the second pin 5, and the third pin 6 is placed outside the plastic shell 71. The epoxy resin fills the interior of the plastic shell 71. The device is mechanically protected and electrically insulated by the insulating effect of the plastic shell 71. The epoxy resin fills the plastic shell 71. When the epoxy resin is in liquid state, it penetrates into the micro gaps between the chip, the bonding wire, and the pad. After curing, it forms a rigid support to prevent the device from shifting under vibration or impact and to avoid the bonding wire from breaking or the solder joint from detaching.

[0025] Reference Figure 1 Furthermore, the first pin 4 is the trigger signal input terminal, serving as the access point for the external trigger circuit. The second pin 5 is the main current output terminal, serving as the current output electrode of the thyristor and carrying all the operating current. The third pin 6 is the common terminal, serving as both current input and heat dissipation. When the third pin 6 is used for current input, it is at the same potential as the MT1 terminal 11 of the thyristor chip 1, forming the main circuit input electrode. When the third pin 6 is used for heat dissipation, it provides a low thermal resistance path in conjunction with the heat dissipation substrate 3, solving the problem of concentrated heat generation of the thyristor chip 1.

[0026] 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 thyristor with zero-crossing oscillation protection, characterized in that: The package includes a silicon controlled rectifier (SCR) chip, a bidirectional trigger diode chip, a heat dissipation substrate, a first pin, a second pin, a third pin, and a package. The top layer of the heat dissipation substrate has independent first and second pads. The MT1 terminal of the SCR chip is soldered to the first pad. The bottom electrode of the bidirectional trigger diode chip is soldered to the second pad. The top electrode of the bidirectional trigger diode chip is connected to the gate terminal of the SCR chip via a first bonding wire. The second pad is connected to the first pin via a second bonding wire. The MT2 terminal of the SCR chip is connected to the second pin via a third bonding wire. The third pin is soldered to the first pad. The package covers the SCR chip, the bidirectional trigger diode chip, the heat dissipation substrate, the first bonding wire, the second bonding wire, and the third bonding wire.

2. The thyristor for preventing zero-crossing oscillation according to claim 1, characterized in that: The heat dissipation substrate is a copper-clad ceramic substrate or an insulating metal substrate.

3. The thyristor for preventing zero-crossing oscillation according to claim 1, characterized in that: The first bonding wire, the second bonding wire, and the third bonding wire are aluminum wires.

4. A thyristor for preventing zero-crossing oscillation according to claim 1, characterized in that: The solder is solder paste.

5. A thyristor for preventing zero-crossing oscillation according to claim 1, characterized in that: The package includes a plastic shell and epoxy resin. The plastic shell covers the silicon controlled rectifier chip, the bidirectional trigger diode chip, the heat dissipation substrate, the first bonding wire, the second bonding wire, and the third bonding wire. One end of the first pin, the second pin, and the third pin is placed inside the plastic shell, and the other end of the first pin, the second pin, and the third pin is placed outside the plastic shell. The epoxy resin fills the interior of the plastic shell.

6. A thyristor for preventing zero-crossing oscillation according to claim 1, characterized in that: The thyristor chip is a unidirectional thyristor chip.

7. A thyristor for preventing zero-crossing oscillation according to claim 1, characterized in that: The bidirectional trigger diode chip has a five-layer symmetrical structure.

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