Ultra-wideband electrostatic protection structure

Abstract

The invention relates to an ultra-wideband electrostatic protection structure, which comprises an internal circuit, a radio frequency signal link, a radio frequency interface, a conical inductor and an ESD protection circuit, and is characterized in that the internal circuit is connected with the radio frequency interface through the radio frequency signal link, the conical inductor is connected in series between the radio frequency signal link and the ESD protection circuit, one end of the ESD protection circuit is connected with the conical inductor, and the other end of the ESD protection circuit is grounded; a radio frequency signal of the internal circuit is transmitted to the radio frequency interface through the radio frequency signal link, and the conical inductor blocks the radio frequency signal; the radio frequency interface receives external static electricity, transmits the external static electricity to the internal circuit through the radio frequency signal link, transmits the external static electricity to the ESD protection circuit through the conical inductor, and is grounded through the ESD protection circuit. The ultra-wideband electrostatic protection structure is not only suitable for a radio frequency front end of a network analyzer, but also can be used for radio frequency front ends of other testing and measuring instruments and equipment. According to the invention, radio frequency signals can be effectively blocked, external electrostatic energy is guided to the ground, damage to an internal circuit is reduced, and the electrostatic protection effect is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of communication test instruments and meters, particularly to the transmitter field of a vector network analyzer, and specifically refers to an ultra-wideband electrostatic protection structure. Background Art

[0002] In daily life, static electricity is invisible and ubiquitous, often bringing various harms to us quietly, such as causing touch screen malfunctions, communication interface failures, burning out internal components of instruments, and so on.

[0003] In order to reduce or even eliminate the adverse effects of static electricity, various electrostatic protection measures need to be taken. Commonly used electrostatic protection measures include the method of series high-voltage capacitors, the method of using LC filters, the spark gap method, the method of parallel ESD protection devices, etc., among which the parallel TVS diode is the most commonly used. Such electrostatic protection measures are usually used in low-speed and low-frequency network interfaces, such as power interfaces, USB interfaces, network ports, serial ports, and so on.

[0004] However, for radio frequency signal interfaces, the above-mentioned electrostatic protection measures often have many deficiencies and cannot achieve good electrostatic protection effects. As Figure 1 shown, the radio frequency signals of the internal circuit, or even higher-frequency millimeter-wave signals, are transmitted to the radio frequency signal interface through the radio frequency signal link. At the same time, external static electricity is also transmitted to the internal circuit through the radio frequency signal link, causing damage to the internal circuit. The radio frequency signal link is both a path for internal radio frequency signals to be transmitted outward and a physical path for external harmful static electricity to be transmitted inward.

[0005] In order to reduce or even eliminate the damage of external static electricity to the internal circuit, it is usually necessary to connect an ESD protection circuit to ground in parallel on the radio frequency signal link between the radio frequency interface and the internal circuit. As Figure 1 shown, when external static electricity reaches the ESD protection circuit along the radio frequency signal link through the radio frequency interface, most of the static electricity energy is guided to the ground, reducing the static electricity energy reaching the internal circuit and achieving the protection effect on the internal circuit.

[0006] As Figure 1 shown, connecting an ESD protection circuit in parallel usually generates a parasitic parallel capacitance Cj to ground. The capacitance value of Cj is relatively small, generally between 1 pF and 1 nF. From the characteristic of high impedance for DC and low impedance for AC of the capacitor, the parasitic parallel capacitance Cj to ground provides a path for radio frequency signals to the ground, which will cause radio frequency signal leakage, resulting in radio frequency signal mismatch at the radio frequency interface and affecting the accuracy of test and measurement. As Figure 1 shown, due to the relatively small capacitance value of the parasitic parallel capacitance Cj to ground, this solution is applicable for lower frequencies, but for high-frequency and even millimeter-wave frequency bands, Figure 1 the solution shown is not applicable. Summary of the Invention

[0007] The object of the present invention is to overcome the above-mentioned disadvantages of the prior art, and provide an ultra-wideband electrostatic protection structure that has low damage to the circuit, high accuracy, and a relatively wide range of applications.

[0008] To achieve the above object, the ultra-wideband electrostatic protection structure of the present invention is as follows:

[0009] The ultra-wideband electrostatic protection structure, its main feature is that the structure includes an internal circuit, a radio frequency signal link, a radio frequency interface, a tapered inductor, and an ESD protection circuit. The internal circuit is connected to the radio frequency interface through the radio frequency signal link. The tapered inductor is connected in series between the radio frequency signal link and the ESD protection circuit. One end of the ESD protection circuit is connected to the tapered inductor, and the other end is grounded. The radio frequency signal of the internal circuit is transmitted to the radio frequency interface through the radio frequency signal link. The tapered inductor blocks the radio frequency signal. The radio frequency interface receives external static electricity, transmits it to the internal circuit through the radio frequency signal link, and transmits it to the ESD protection circuit through the tapered inductor, and is grounded through the ESD protection circuit.

[0010] Preferably, the structure further includes a first capacitor C1. The first capacitor C1 is connected in series on the radio frequency signal link between the internal circuit and the tapered inductor, and is used to cut off the physical path of external static electricity reaching the internal circuit along the radio frequency signal link.

[0011] Preferably, the structure includes a plurality of tapered inductors. The plurality of tapered inductors are connected in parallel and are all connected between the ESD protection circuit and the radio frequency signal link, and are used to improve the stability of the overall anti-static protection circuit.

[0012] Preferably, the structure includes a plurality of ESD protection circuits. The plurality of ESD protection circuits are connected in series between the tapered inductor and the ground.

[0013] Adopting the ultra-wideband electrostatic protection structure of the present invention is not only applicable to the radio frequency front end of a network analyzer, but also can be used for the radio frequency front end of other test and measurement instrument devices. The present invention adopts a combination of a tapered inductor and an ESD protection circuit, which can effectively block radio frequency signals while guiding external static electricity energy to the ground, reducing damage to the internal circuit and improving the electrostatic protection effect. The design of the tapered inductor can effectively block radio frequency signals without affecting the conduction of static electricity, making this technical solution particularly suitable for the electrostatic protection of ultra-wideband radio frequency signal interfaces. Through the design of connecting a plurality of tapered inductors in parallel and a plurality of ESD protection circuits in series, the stability of the overall anti-static protection circuit is improved, and the risk of circuit failure caused by electrostatic shock is reduced. This solution can adjust the number and parameters of the tapered inductor and the ESD protection circuit according to actual needs to adapt to radio frequency signal interfaces with different frequencies and power levels, and has good flexibility and scalability. Brief Description of the Drawings

[0014] Figure 1 FIG. 1 is a schematic structural diagram of a common electrostatic protection circuit scheme for a radio frequency signal link in the prior art.

[0015] Figure 2 FIG. 2 is a schematic circuit diagram of the ultra-wideband electrostatic protection structure of the present invention.

[0016] Figure 3 FIG. 3 is a schematic diagram of an embodiment of the ultra-wideband electrostatic protection structure of the present invention.

[0017] Figure 4 FIG. 4 is a schematic diagram of an electrostatic protection scheme with a tapered inductor in parallel in the ultra-wideband electrostatic protection structure of the present invention.

[0018] Figure 5 FIG. 5 is a schematic diagram of an electrostatic protection scheme with an ESD protection circuit in series in the ultra-wideband electrostatic protection structure of the present invention. Detailed Description of the Preferred Embodiments

[0019] In order to more clearly describe the technical content of the present invention, the following will be further described in conjunction with specific embodiments.

[0020] The ultra-wideband electrostatic protection structure of the present invention includes an internal circuit, a radio frequency signal link, a radio frequency interface, a tapered inductor, and an ESD protection circuit. The internal circuit is connected to the radio frequency interface through the radio frequency signal link. The tapered inductor is connected in series between the radio frequency signal link and the ESD protection circuit. One end of the ESD protection circuit is connected to the tapered inductor, and the other end is grounded. The radio frequency signal of the internal circuit is transmitted to the radio frequency interface through the radio frequency signal link. The tapered inductor blocks the radio frequency signal. The radio frequency interface receives external static electricity, transmits it to the internal circuit through the radio frequency signal link, and transmits it to the ESD protection circuit through the tapered inductor, and is grounded through the ESD protection circuit.

[0021] As a preferred embodiment of the present invention, the structure further includes a first capacitor C1. The first capacitor C1 is connected in series on the radio frequency signal link between the internal circuit and the tapered inductor, and is used to cut off the physical path of external static electricity reaching the internal circuit along the radio frequency signal link.

[0022] As a preferred embodiment of the present invention, the structure includes a plurality of tapered inductors. The plurality of tapered inductors are connected in parallel and are all connected between the ESD protection circuit and the radio frequency signal link, and are used to improve the stability of the overall electrostatic protection circuit.

[0023] As a preferred embodiment of the present invention, the structure includes a plurality of ESD protection circuits. The plurality of ESD protection circuits are connected in series and are connected between the tapered inductor and the ground.

[0024] In the specific embodiments of the present invention, as Figure 2 shown, the ESD protection circuit of the present invention includes an internal circuit, a radio frequency (RF) signal link, an RF interface, a tapered inductor, and an ESD protection circuit. Among them, the tapered inductor is connected in series between the RF signal link and the ESD protection circuit.

[0025] The ESD protection circuit can be well applied to the electrostatic protection of RF interfaces in the millimeter wave band, and can well solve Figure 1 the problems of the prior art shown in

[0026] The tapered inductor not only has the function of passing direct current and blocking alternating current, but also has excellent distributed parameter frequency response characteristics, and can easily achieve a high impedance state for millimeter wave signals within 50 GHz, and at the same time has good port return loss. Relying on its excellent frequency response, the tapered inductor is widely used in the bias circuit of millimeter wave distributed amplifiers. In the present invention, the tapered inductor is used in the ESD protection circuit of the RF circuit.

[0027] As Figure 2 shown, the RF signal of the internal circuit, or a higher frequency millimeter wave signal, is transmitted to the RF interface through the RF signal link. Since the tapered inductor has excellent characteristics of passing direct current and blocking alternating current in the ultra-wideband frequency range up to millimeter waves, the RF signal will be blocked by the tapered inductor and cannot be transmitted to the ground through the parasitic capacitance Cj of the ESD protection circuit. Thus, it is ensured that when the RF signal is transmitted along the RF signal link to the RF interface, it is not affected by the tapered inductor and the ESD protection circuit connected in parallel on the RF signal link.

[0028] As Figure 2 shown, the tapered inductor is a good direct current transmission channel. When external static electricity is transmitted from the RF interface along the RF signal link to the internal circuit, it reaches the ESD protection circuit through the tapered inductor and is then guided to the ground by the ESD protection circuit, realizing the anti-static protection of the internal circuit.

[0029] As Figure 3 shown, in order to better cut off the physical path of external static electricity reaching the internal circuit along the RF signal link, a capacitor C1 is connected in series on the RF signal link between the internal circuit and the tapered inductor. The RF signal can pass through the capacitor C1, while static electricity cannot pass through the capacitor C1. Combining the tapered inductor and the ESD protection circuit can better protect the internal circuit from damage by static electricity. In order to broaden the operating frequency and be applicable to millimeter wave frequencies, the capacitor C1 can be selected as an RF inductor with better high-frequency characteristics.

[0030] As Figure 4As shown, the anti-static current capacity of the tapered inductor can be improved by connecting tapered inductors in parallel, and the stability of the overall anti-static protection circuit can be better improved.

[0031] As Figure 5 shown, the ESD protection ability can be enhanced by connecting ESD protection circuits in series. At the same time, multiple parasitic capacitances Cj1, Cj2, etc. to ground form a parallel capacitance, making the total parasitic capacitance Cj to ground smaller and the high-frequency signals that can pass through higher. In this way, the frequency of the high-frequency signals that are not affected can also be correspondingly increased.

[0032] The technical solution of the present invention focuses on solving the circuit electrostatic protection in the radio frequency millimeter wave band through various combinations of tapered inductors and anti-static diodes, and good electrostatic protection can be achieved without deteriorating the radio frequency or millimeter wave signals.

[0033] For the specific implementation solution of this embodiment, reference can be made to the relevant descriptions in the above embodiments, and details will not be repeated here.

[0034] It can be understood that the same or similar parts in the above embodiments can be referred to each other, and the content not detailed in some embodiments can be referred to the same or similar content in other embodiments.

[0035] It should be noted that in the description of the present invention, terms such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description of the present invention, unless otherwise specified, the meaning of "a plurality" refers to at least two.

[0036] In the description of this specification, the description referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0037] The ultra-wideband electrostatic protection structure of the present invention is not only applicable to the RF front-end of network analyzers, but also can be used for the RF front-ends of other test and measurement instrument devices. The present invention adopts a combination of a tapered inductor and an ESD protection circuit, which can effectively block RF signals while guiding external electrostatic energy to the ground, reducing damage to internal circuits and improving the electrostatic protection effect. The design of the tapered inductor can effectively block RF signals without affecting the conduction of static electricity, making this technical solution particularly suitable for electrostatic protection of ultra-wideband RF signal interfaces. Through the design of parallel connection of multiple tapered inductors and series connection of multiple ESD protection circuits, the stability of the overall anti-static protection circuit is improved, and the risk of circuit failure caused by electrostatic shock is reduced. This solution can adjust the quantity and parameters of the tapered inductor and the ESD protection circuit according to actual needs to adapt to RF signal interfaces with different frequencies and power levels, and has good flexibility and scalability.

[0038] In this specification, the present invention has been described with reference to its specific embodiments. However, it is obvious that various modifications and variations can still be made without departing from the spirit and scope of the present invention. Therefore, the specification and drawings should be regarded as illustrative rather than restrictive.

Claims

1. An ultra-wideband electrostatic protection structure, characterized in that: The structure includes an internal circuit, a radio frequency signal link, a radio frequency interface, a conical inductor and an ESD protection circuit. The internal circuit is connected to the radio frequency interface through the radio frequency signal link, the conical inductor is connected in series between the radio frequency signal link and the ESD protection circuit, one end of the ESD protection circuit is connected to the conical inductor, and the other end is grounded; the radio frequency signal of the internal circuit is transmitted to the radio frequency interface through the radio frequency signal link, and the conical inductor blocks the radio frequency signal; the radio frequency interface receives external static electricity, transmits it to the internal circuit through the radio frequency signal link, and transmits it to the ESD protection circuit through the conical inductor, and is grounded through the ESD protection circuit.

2. The ultra-wideband electrostatic protection structure according to claim 1, characterized in that: The structure further includes a first capacitor C1, which is connected in series to the radio frequency signal link between the internal circuit and the conical inductor, and is used to cut off the physical path of external static electricity reaching the internal circuit along the radio frequency signal link.

3. The ultra-wideband electrostatic protection structure according to claim 1, characterized in that: The structure includes a plurality of conical inductors, which are connected in parallel and are all connected between the ESD protection circuit and the radio frequency signal link, so as to improve the stability of the overall anti-static protection circuit.

4. The ultra-wideband electrostatic protection structure according to claim 1, characterized in that: The structure comprises a plurality of ESD protection circuits, which are connected in series and between the conical inductor and the ground.

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