High-integration double-base-island silicon controlled rectifier

Abstract

The utility model relates to a high-integration double-base-island silicon controlled rectifier which comprises a lead frame, a first lead, a second lead, a third lead and two silicon controlled rectifier chips of the same specification, anodes of the two silicon controlled rectifier chips are electrically connected through the first lead, and cathodes of the two silicon controlled rectifier chips are electrically connected through the second lead. Gate poles of the two silicon controlled rectifier chips are electrically connected through a third lead, the lead frame comprises a shell, an insulating substrate is arranged at the bottom of the shell, the two silicon controlled rectifier chips are fixed on the top surface of the insulating substrate, an anode pin, a cathode pin and a gate pole pin are embedded in the shell, and the lead frame further comprises a fourth lead, a fifth lead and a sixth lead. The anode of a silicon controlled rectifier chip is electrically connected with the anode pin through a fourth lead, the cathode of the silicon controlled rectifier chip is electrically connected with the cathode pin through a fifth lead, and the gate pole of the silicon controlled rectifier chip is electrically connected with the gate pole pin. According to the invention, the condition of circuit false triggering caused by reduction of a silicon controlled rectifier gate triggering value due to overheat of the base island is reduced.

Description

Technical Field

[0001] This application relates to the field of thyristors, and more specifically, to a highly integrated bi-base island thyristor. Background Technology

[0002] A silicon controlled rectifier (SCR) is a semiconductor device, belonging to the thyristor class of devices, primarily used in power control and switching circuits. It is a four-layer, three-terminal semiconductor device with unidirectional conductivity and switching control characteristics, widely used in AC current regulation, rectification, pulse width modulation (PWM), and other applications.

[0003] A thyristor typically consists of a lead frame and a silicon substrate. The silicon substrate is connected to the circuit via the lead frame. Different semiconductor regions are formed on the silicon substrate through doping, diffusion, and other techniques, thereby constructing a thyristor chip with a PNPN structure. The thyristor chip is composed of alternating P-type and N-type semiconductor materials, specifically having four semiconductor layers: the P1 layer, which is connected to the anode of the circuit and is called the anode; and the N1 layer, which is the junction between the anode and the anode contact point. The first PN junction, PN junction 1, is formed. The P2 layer, which is the gate contact, contacts the N1 layer to form the second PN junction, PN junction 2. This region is the control terminal of the thyristor and is usually connected to the control circuit, called the "gate". By applying a positive current or voltage to the gate, the turn-on and turn-off of the thyristor can be controlled. The N2 layer is connected to the cathode of the circuit and is called the cathode. When the thyristor is turned on, current flows into the cathode. The N2 layer contacts the P2 layer to form the third PN junction, PN junction 3.

[0004] When there is no trigger signal (no voltage at the gate), the three PN junctions of the thyristor chip form a state that prevents current flow. Current cannot flow from the anode to the cathode. When the gate receives a certain trigger current, the potential change of PN junction 1 and NP junction 2 causes a change in the PN junctions within the PNPN structure, switching the thyristor chip from the off state to the on state. At this point, current can flow from the anode to the cathode. The function of PN junction 3 is to maintain this on state. Once on, the thyristor chip will remain on until the main current drops below a certain value, at which point it will automatically turn off. The gate of a thyristor chip typically has a trigger value. Only when the current flowing through the gate is greater than the trigger value can the potential change of PN junction 1 and NP junction 2 be triggered. The gate trigger value has a negative correlation with temperature; the higher the temperature, the smaller the gate trigger current. Therefore, when the temperature of the thyristor chip is high, it can easily lead to false circuit activation.

[0005] In related technologies, thyristors typically have only one base island, i.e., a single silicon substrate. All current is introduced through this base island and passes through the PN junction of the entire device. Due to the relatively simple and concentrated conduction path of current and heat, the heat dissipation effect of a single-base-island thyristor is relatively poor. Heat is mainly concentrated on a single base island, which can easily cause the circuit to be accidentally turned on. Utility Model Content

[0006] To address the issue of relatively poor heat dissipation in single-island thyristors, where heat is concentrated on a single island and can easily cause accidental circuit activation, this application provides a highly integrated dual-island thyristor.

[0007] A highly integrated dual-base island thyristor includes a lead frame, a first lead, a second lead, a third lead, and two thyristor chips of the same specification. The anodes of the two thyristor chips are electrically connected through the first lead, the cathodes of the two thyristor chips are electrically connected through the second lead, and the gates of the two thyristor chips are electrically connected through the third lead. The lead frame includes a housing, and an insulating substrate is disposed at the bottom of the housing. The two thyristor chips are fixed to the top surface of the insulating substrate. An anode pin, a cathode pin, and a gate pin are embedded in the housing. The lead frame also includes a fourth lead, a fifth lead, and a sixth lead. The anode of one thyristor chip is electrically connected to the anode pin through the fourth lead, and the cathode of the same thyristor chip is electrically connected to the cathode pin through the fifth lead. The gate of the other thyristor chip is electrically connected to the gate pin.

[0008] Preferably, the housing is a closed structure covering the insulating substrate, and potting compound is injected inside the housing to fix the two thyristor chips onto the insulating substrate. One end of the anode pin, cathode pin, and gate pin all extend outside the housing.

[0009] Preferably, the potting compound is epoxy resin.

[0010] Preferably, the top surface of the insulating substrate is provided with two mounting platforms spaced apart, and the two thyristor chips are respectively fixed on the top surfaces of the two mounting platforms, and the size of the top surface of the mounting platform matches the size of the thyristor chip.

[0011] Preferably, the anode pin, cathode pin, and gate pin are all made of copper sheet.

[0012] Preferably, the housing is made of plastic material.

[0013] The beneficial technical effects of this application are as follows: By integrating two thyristor chips in a housing and setting the two thyristor chips in parallel, the two thyristor chips form two base islands. Current and heat can be distributed through the two base islands, and the local heat load is effectively dispersed, reducing the heat concentration of a single base island, thereby reducing the risk of overheating and reducing the situation where the circuit is falsely triggered due to the reduction of the thyristor gate trigger value caused by the overheating of the base island. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of a highly integrated dual-base island thyristor structure according to this embodiment.

[0015] Figure 2 This is a schematic diagram of a highly integrated dual-base island thyristor structure in this embodiment after removing the top cover.

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

[0017] Reference numerals: 1. Lead frame; 11. Housing; 111. Lower housing; 1111. Groove; 1112. First slot; 1113. Second slot; 112. Top cover; 1121. Fastening groove; 1122. First clearance groove; 1123. Second clearance groove; 13. Insulating substrate; 131. Mounting platform; 14. Anode pin; 15. Gate pin; 16. Cathode pin; 2. First lead; 3. Second lead; 4. Third lead; 5. Thyristor chip; 6. Encapsulating resin. Detailed Implementation

[0018] 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.

[0019] Reference Figure 1 and Figure 2A highly integrated dual-base island thyristor includes a lead frame 1, a first lead 2, a second lead 3, a third lead 4, and two thyristor chips 5 of the same specifications. The lead frame 1 includes a plastic housing 11, which includes a lower housing 111 and an upper cover 112. The lower housing 111 is provided with a groove 1111, and an insulating substrate 13 is provided on the bottom surface of the groove 1111. Two mounting platforms 131 are provided on the top surface of the insulating substrate 13 at intervals. The two thyristor chips 5 are placed on the top surface of the mounting platforms 131. The size of the top surface of the mounting platforms 131 matches the size of the thyristor chips 5, which facilitates the positioning and installation of the thyristor chips 5 and ensures accurate installation. Both ends of the first lead 2 are soldered to the anodes of the two thyristor chips 5 with solder paste, both ends of the second lead 3 are soldered to the cathodes of the two thyristor chips 5 with solder paste, and both ends of the third lead 4 are soldered to the gates of the two thyristor chips 5 with solder paste. The two thyristor chips 5 are connected in parallel through the connection of the leads.

[0020] Reference Figure 2 Two first slots 1112 are recessed on one side of the top surface of the lower shell 111. An anode pin 14 and a gate pin 15 are respectively embedded in the two first slots 1112. A second slot 1113 is recessed on the other side of the top surface of the lower shell 111. A cathode pin 16 is embedded in the second slot 1113. The anode pin 14, cathode pin 16, and gate pin 15 are all made of copper sheets, with one end extending outside the lower shell 111 and the other end placed in the groove 1111. The lead frame 1 also includes a fourth lead, a fifth lead, and a sixth lead. One end of the fourth lead is connected to a thyristor chip 5. The anode of the circuit is soldered with solder paste, and the other end of the fifth lead is soldered with solder paste to the end of the anode pin 14 located in the groove 1111. One end of the fifth lead is soldered with solder paste to the cathode of the thyristor chip 5, and the other end is soldered with solder paste to the end of the cathode pin 16 located in the groove 1111. One end of the sixth lead is soldered with solder paste to the gate of another thyristor chip 5, and the other end is soldered with solder paste to the end of the gate pin 15 located in the groove 1111. The anode of the circuit is connected through the anode pin 14, the cathode of the circuit is connected through the cathode pin 16, and the signal control source is connected through the gate pin 15.

[0021] Reference Figure 2 The groove 1111 of the lower shell 111 is filled with potting compound 6. The two thyristor chips 5 are fixed to the insulating substrate 13 by the potting compound 6, and the first lead 2, the second lead 3, the third lead 4, the fourth lead, the fifth lead and the first lead 2 are all in the potting compound 6. The anode pin 14, the cathode pin 16 and the gate pin 15 are all in the potting compound 6 at one end in the groove 1111. The potting compound 6 is used to seal and protect the thyristor chips 5 and the leads. The potting compound 6 is preferably epoxy resin.

[0022] Reference Figure 3 The bottom surface of the upper cover 112 is recessed with a fastening groove 1121 that matches the outer contour and size of the lower shell 111. Two first clearance grooves 1122 are opened on one side of the bottom surface of the upper cover 112, which are respectively aligned with the anode pin 14 and the gate pin 15. A second clearance groove 1123 is opened on the other side of the bottom surface of the upper cover 112, which is aligned with the cathode pin 16. The lower shell 111 is fastened into the fastening groove 1121 of the upper cover 112 for fixation. The two first clearance grooves 1122 respectively avoid the anode pin 14 and the gate pin 15, and the second clearance groove 1123 avoids the cathode pin 16, thus achieving fastening clearance. The upper cover 112 and the lower shell 111 constitute a closed structure covering the insulating substrate 13, thereby further protecting the thyristor chip 5.

[0023] The implementation principle of the highly integrated dual-base-island thyristor of this application is as follows: by integrating two thyristor chips 5 in a housing 11, and the two thyristor chips 5 are arranged in parallel, the two thyristor chips 5 form two base islands. Current and heat can be distributed through the two base islands, the local heat load is effectively dispersed, the heat concentration of a single base island is reduced, thereby reducing the risk of overheating and reducing the situation where the gate trigger value of the thyristor decreases due to overheating of the base island, which leads to circuit false triggering.

[0024] 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 highly integrated dual-base island thyristor, characterized in that: The device includes a lead frame, a first lead, a second lead, a third lead, and two identical silicon controlled rectifier (SCR) chips. The anodes of the two SCR chips are electrically connected via the first lead, the cathodes of the two SCR chips are electrically connected via the second lead, and the gates of the two SCR chips are electrically connected via the third lead. The lead frame includes a housing, and an insulating substrate is disposed at the bottom of the housing. The two SCR chips are fixed to the top surface of the insulating substrate. An anode pin, a cathode pin, and a gate pin are embedded in the housing. The lead frame also includes a fourth lead, a fifth lead, and a sixth lead. The anode of one SCR chip is electrically connected to the anode pin via the fourth lead, and the cathode of that SCR chip is electrically connected to the cathode pin via the fifth lead. The gate of the other SCR chip is electrically connected to the gate pin. The housing is a closed structure that covers the insulating substrate. The housing is filled with potting compound to fix the two thyristor chips onto the insulating substrate. One end of the anode pin, cathode pin, and gate pin all protrude outside the housing.

2. The highly integrated dual-base island thyristor according to claim 1, characterized in that: The potting compound is epoxy resin.

3. The highly integrated dual-base island thyristor according to claim 1, characterized in that: The top surface of the insulating substrate is provided with two mounting platforms spaced apart. The two thyristor chips are respectively fixed on the top surfaces of the two mounting platforms, and the size of the top surface of the mounting platform matches the size of the thyristor chip.

4. The highly integrated dual-base island thyristor according to claim 1, characterized in that: The anode pin, cathode pin, and gate pin are all made of copper sheet.

5. The highly integrated dual-base island thyristor according to claim 1, characterized in that: The shell is made of plastic material.

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