Semiconductor discharge tube composite piezoresistor structure

Abstract

The utility model discloses a composite piezoresistor structure of a semiconductor discharge tube, and belongs to the field of piezoresistors. Comprising a piezoresistor and a semiconductor discharge tube, the piezoresistor is connected with the semiconductor discharge tube through a wire, the other end, connected with the piezoresistor, of the semiconductor discharge tube is provided with a discharge tube wire, and the discharge tube wire is connected with the wire between the piezoresistor and the semiconductor discharge tube. According to the utility model, through the combination of the piezoresistor and the semiconductor discharge tube, the composite piezoresistor of the TSS (semiconductor discharge tube) and the MOV (piezoresistor) is designed, and the service life of the MOV in normal operation can be effectively prolonged by adopting miniaturized patch packaging. Compared with the scheme that the MOV is connected with the GDT in series in the prior art, the scheme has the advantages that the action time of the TSS is shorter, the residual voltage is lower after the TSS is broken down, the leakage current is lower, the reliability is higher, more times of breakdown can be endured, and the service life is longer.

Description

Technical Field

[0001] The utility model belongs to the field of varistor, and specifically relates to a semiconductor discharge tube composite varistor structure. Background Art

[0002] In the power port part of the integrated circuit, due to cost and other considerations, MOV (metal oxide varistor) is usually used to protect the power port from overvoltage. MOV is set in the power port part to effectively prevent voltage surges or voltage surges from damaging the store equipment. The principle is that when the voltage exceeds the rated value of the MOV, the MOV will become a low-resistance state and divert the overvoltage to the ground line to protect the equipment from damage.

[0003] However, simply adding MOV to the power port for protection still poses the risk of aging and fire. Therefore, in the prior art, a GDT (gas transistor) is usually connected in series after the MOV. The role of the GDT is to reduce the voltage stress on the MOV when it is working normally, thereby delaying the aging of the MOV and extending the actual working life of the MOV.

[0004] The GDT component itself also has some problems. For example, the breakdown voltage error of GDT is large, generally ±20% to ±30%, so sufficient margin must be considered during design. In addition, the action time of GDT is relatively long. According to the surge waveform during actual use, the residual pressure generated is relatively high.

[0005] Therefore, a new solution is needed that can better replace GDT to protect MOV. Utility Model Content

[0006] In view of the above problems existing in the prior art, the purpose of the utility model is to provide a semiconductor discharge tube composite varistor structure.

[0007] In order to solve the above problems, the technical solution adopted by the utility model is as follows:

[0008] A semiconductor discharge tube composite varistor structure comprises a varistor and a semiconductor discharge tube, wherein the varistor is connected to the semiconductor discharge tube via a wire, and a discharge tube wire is arranged at the other end of the semiconductor discharge tube connected to the varistor, and the discharge tube wire is connected to the wire between the varistor and the semiconductor discharge tube.

[0009] The varistor and the semiconductor discharge tube are respectively a varistor layer and a semiconductor discharge tube layer, the semiconductor discharge tube layer is arranged above the varistor layer, the wire connecting the semiconductor discharge tube and the varistor is a wire layer, a discharge tube wire is arranged above the semiconductor discharge tube layer and connected to the wire layer, a varistor wire is arranged below the varistor layer, and the varistor layer, the semiconductor discharge tube layer, the wire layer and the wire package form an integrated structure.

[0010] The package is SMT package.

[0011] The wire connecting the semiconductor discharge tube layer and the wire layer is the positive electrode, and the wire of the varistor layer is the negative electrode.

[0012] The packaging is SMA, SMB and SMC structural packaging.

[0013] The packaging structure is an SMC packaging structure, the length of the SMC packaging structure is 8-8.1 mm, the width of the SMC packaging structure is 6.2-6.3 mm, and the height of the SMC packaging structure is 3.7-3.9 mm.

[0014] Compared with the prior art, the beneficial effects of the utility model are:

[0015] The utility model designs a composite varistor of TSS (semiconductor discharge tube) and MOV (varistor) by combining a varistor and a semiconductor discharge tube, and adopts a miniaturized patch package, which can effectively extend the working life of MOV in normal operation. Compared with the MOV series GDT solution in the prior art, the TSS has a shorter action time, lower residual pressure and leakage current after the TSS is broken down, and has higher reliability, can withstand more times of breakdown, and has a longer service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a cross-sectional schematic diagram of the utility model;

[0017] Figure 2 This is a schematic diagram of the circuit structure of the utility model;

[0018] Figure 3 This is a comparison chart of MOV leakage current change trends;

[0019] Figure 4 This is a comparison chart of the breakdown voltage variation trend of MOV;

[0020] In the figure: 1. Packaging layer; 2. Wire layer; 3. Semiconductor discharge tube; 4. Varistor. DETAILED DESCRIPTION

[0021] The utility model is further described below in conjunction with specific embodiments.

[0022] like Figure 1 As shown, the utility model mainly includes a semiconductor discharge tube 3 and a varistor 4.

[0023] The present solution adopts an SMT packaging structure, in which a semiconductor discharge tube 3 is arranged above a varistor 4, a wire layer 2 is arranged between the semiconductor discharge tube 3 and the varistor 4, a discharge tube wire layer 2 is led out from above the semiconductor discharge tube 3, a varistor wire layer 2 is led out from below the varistor 4, and the wire layer arranged between the semiconductor discharge tube 3 and the varistor 4 is connected to the wire layer led out from above the semiconductor discharge tube 3 as the positive electrode of the composite varistor, and the wire layer 2 led out from below the varistor 4 serves as the negative electrode of the composite varistor.

[0024] The structure of this solution is improved based on the structure of GDT (gas discharge tube) in series with MOV in the prior art, and the structure is replaced by a structure of TSS (semiconductor discharge tube 3) and MOV in series, such as Figure 2 The principle of improvement is based on the different working principles of GDT and TSS. Both are switch-type devices, but their shutdown mechanisms are different. TSS relies on current to shut down, while GDT relies on voltage to shut down. When GDT is broken down and turned on, the external voltage will be directly applied to both ends of MOV. It will not shut down until the AC voltage exceeds the zero point of GDT. After TSS is broken down and turned on, as long as the surge current is less than the holding current, TSS will shut down immediately.

[0025] Therefore, in actual use, the action time of TSS is shorter than that of GDT, and it has more significant advantages in terms of breakdown voltage error and lower residual voltage.

[0026] The varistor model used in the comparative test is 14D471K, the TSS model is P3100SB, and the GDT model is PG2D12N470. The varistor is tested in combination with TSS and GDT respectively. The residual pressure data under the 20us-8 / 20us waveform are shown in the following table:

[0027]

[0028] Table 1

[0029] The above combination was used for multiple tests to measure the change trend of each combination when the MOV leakage current gradually increased to about 4.5uA. The test results are as follows: Figure 3 shown.

[0030] It can be seen that when the TSS+MOV combination is used, the number of tests when the MOV leakage current increases to 4.5uA is 4.3 times that of a single MOV and 1.4 times that of the GDT+MOV combination.

[0031] At the same time, according to the definition of MOV degradation failure mode in GB18802.331-2007: if the nominal varistor of the MOV is less than 90% of that before the test, it is determined that the test product has degraded.

[0032] The trend comparison chart after multiple tests is as follows Figure 4 shown.

[0033] The combination of TSS+MOV is used. The number of experiments that the MOV undergoes before aging is 4.4 times that of a single MOV, and 1.5 times that of a GDT+MOV combination.

[0034] Therefore, the combination of TSS+MOV can effectively extend the service life of MOV, and compared with the commonly used combination of GDT+MOV in the prior art, it also has a more significant improvement, achieving lower residual pressure, lower leakage current, and better effect of extending the life of MOV.

[0035] For the structure in this scheme, the SMC patch package is used in this embodiment, and its internal structure is as follows Figure 1 As shown in the figure, the length of the sample after packaging is 8.01mm, the width is 6.22mm, and the height is 3.78mm. The test results are consistent with the data obtained during the test. Therefore, the structure is feasible for miniaturized SMD packaging. The product produced is a semiconductor discharge tube composite varistor, which realizes the miniaturization, SMD, low-cost and multifunctionality of the product.

Claims

1. A semiconductor discharge tube composite varistor structure, comprising a varistor and a semiconductor discharge tube, characterized in that: The varistor is connected to the semiconductor discharge tube through a wire, and the other end of the semiconductor discharge tube connected to the varistor is provided with a discharge tube wire, and the discharge tube wire is connected to the wire between the varistor and the semiconductor discharge tube; The varistor and the semiconductor discharge tube are respectively a varistor layer and a semiconductor discharge tube layer, the semiconductor discharge tube layer is arranged above the varistor layer, the wire connecting the semiconductor discharge tube and the varistor is a wire layer, a discharge tube wire is arranged above the semiconductor discharge tube layer and connected to the wire layer, a varistor wire is arranged below the varistor layer, and the varistor layer, the semiconductor discharge tube layer, the wire layer and the wire package form an integrated structure.

2. The semiconductor discharge tube composite varistor structure according to claim 1, characterized in that: The package is SMT package.

3. The semiconductor discharge tube composite varistor structure according to claim 2, characterized in that: The wire connecting the semiconductor discharge tube layer and the wire layer is the positive electrode, and the wire of the varistor layer is the negative electrode.

4. The semiconductor discharge tube composite varistor structure according to claim 3, characterized in that: The packaging is SMA, SMB and SMC structural packaging.

5. The semiconductor discharge tube composite varistor structure according to claim 4, characterized in that: The packaging structure is an SMC packaging structure, the length of the SMC packaging structure is 8-8.1 mm, the width of the SMC packaging structure is 6.2-6.3 mm, and the height of the SMC packaging structure is 3.7-3.9 mm.

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