阅读说明：本技术 有源限制系统 (Active confinement system ) 是由 阿赫迈特·阿克塔格 卡格达斯·亚巴桑 于 2017-12-04 设计创作，主要内容包括：在本发明中,提供了一种有源限制系统,适用于保护低噪声放大器(LNA)免受从信号输入端(Ri)接收到的高功率信号的影响。所述有源限制系统包括至少一个第一开关(T1),其源极(s)连接到栅极电压(Vg)；至少一个第一电阻(R1),连接在第一开关(T1)的栅极(g)和源极(s)之间；至少一个第二电阻(R2),连接在漏极电压(Vd)和第一开关(T1)的漏极(d)之间；至少一个第二开关(T2),其源极(s)连接到所述漏极电压(Vd),其漏极(d)连接到所述信号输入端(Ri)；至少一个第三电阻(R3),连接在第一开关(T1)的漏极(d)和第二开关(T2)的栅极(g)之间；至少一个第一过滤元件(b1),其阻挡DC电流/电压,并连接在第二开关(T2)的源极(s)与地之间。(In the present invention, an active limiting system is provided, adapted to protect a Low Noise Amplifier (LNA) from high power signals received from a signal input (Ri). The active limiting system comprises at least one first switch (T1) whose source(s) is connected to a gate voltage (Vg); at least one first resistor (R1) connected between the gate (g) and the source(s) of the first switch (T1); at least one second resistor (R2) connected between the drain voltage (Vd) and the drain (d) of the first switch (T1); at least one second switch (T2), the source(s) of which is connected to the drain voltage (Vd), the drain (d) of which is connected to the signal input (Ri); at least one third resistor (R3) connected between the drain (d) of the first switch (T1) and the gate (g) of the second switch (T2); at least one first filter element (b1) blocking DC current/voltage and connected between the source(s) of the second switch (T2) and ground.)

1. An active limiting system adapted to protect a Low Noise Amplifier (LNA) from high power signals received from a signal input (Ri), comprising:

-at least one first switch (T1) having at least one source(s), at least one gate (g) and at least one drain (d), the source(s) of which is connected to a gate voltage (Vg), wherein the electrical connection between the source(s) and drain (d) of the first switch (T1) is controlled by the voltage of the gate (g) to the source(s) of the first switch (T1);

-at least one first resistance (R1) connected between the gate (g) and source(s) of the first switch (T1);

-at least one second resistor (R2) connected between a drain voltage (Vd) and the drain (d) of the first switch (T1);

-at least one second switch (T2) having at least one source(s), at least one gate (g) and at least one drain (d), the source(s) of which is connected to the drain voltage (Vd) and the drain (d) of which is connected to the signal input (Ri), wherein the electrical connection between the source(s) and drain (d) of the second switch (T2) is controlled by the gate (g) to source(s) voltage of the second switch (T2);

-at least one third resistor (R3) connected between the drain (d) of the first switch (T1) and the gate (g) of the second switch (T2);

-at least one first filter element (b1) blocking DC current/voltage and connected between the source(s) of the second switch (T2) and ground.

2. The active restriction system of claim 1, wherein: the first switch (T1) is in the form of a HEMT.

3. The active restriction system of claim 1, wherein: the second switch (T2) is in the form of a HEMT.

4. Active limiting system according to claim 1, characterized by comprising at least two second switches (T2) and at least two third resistors (R3).

5. Active limiting system according to claim 1, characterized by comprising at least one voltage damper (a) between the second resistor (R2) and the drain (d) of the first switch (T1).

6. Active limitation system according to claim 5, characterized in that the voltage damper (a) comprises at least one diode.

7. An active limiting system adapted to protect a Low Noise Amplifier (LNA) from high power signals received from a signal input (Ri), comprising

-at least one first switch (T1) having at least one source(s), at least one gate (g) and at least one drain (d), the source(s) of which is connected to a bias voltage (Vb), wherein the electrical connection between the source(s) and drain (d) of the first switch (T1) is controlled by the gate (g) to source voltage of the first switch (T1);

-at least one first resistance (R1) connected between the gate (g) and a gate voltage (Vg) of the first switch (T1);

-at least one second resistor (R2) connected between ground and the drain (d) of the first switch (T1);

-at least one second switch (T2) having at least one source(s), at least one gate (g) and at least one drain (d), the source(s) thereof being connected to ground and the drain (d) thereof being connected to a signal input terminal (Ri), wherein the electrical connection between the source(s) and drain (d) of the second switch (T2) is controlled by the gate (g) to source(s) voltage of the second switch (T2);

-at least one third resistor (R3) connected between the drain (d) of the first switch (T1) and the gate (g) of the second switch (T2).

8. Active limiting system according to claim 7, characterized by comprising at least two second switches (T2) and at least two third resistors (R3).

Technical Field

The present invention relates to an active limiting system capable of protecting amplifiers, in particular low noise amplifiers, from high input power levels.

Background

A Low Noise Amplifier (LNA) is an electronic amplifier that amplifies the power level of low power signals. Low noise amplifiers make the noise level of the output signal as low as possible when they amplify the power level of the signal. To perform such amplification, the low noise amplifier typically includes at least one transistor (e.g., HEMT).

Low noise amplifiers are commonly used in radio communication systems. Since radio communications typically handle low power signals (especially at the receiving end), low noise amplifiers are used to amplify the power level of the low power signals. In low noise amplifiers, sensitive components are used in order to reduce noise. Although the sensitive components are effective at reducing noise levels, they are generally susceptible to high power inputs. Although ideally no high power signal is sent to the low noise amplifier, the low noise amplifier may be exposed to the high power signal. For example, in radar applications, the transmitted power may reflect off the antenna, and the low noise amplifier may be exposed to the reflected high power through the circulator. In another example, the electromagnetic projectile may generate a high power signal to destroy the low noise amplifier.

Since low noise amplifiers are susceptible to high power signals, different protection systems are used in the known art to protect low noise amplifiers from high power signals. One of the protection systems used in the known art is a passive limiting circuit. An exemplary embodiment of the passive limiting circuit is disclosed in the paper "AnExamino of Recovery Time of an Integrated Limiter/LNA" by Jimloney et al. The passive limiting circuit includes a protection element that limits the voltage level of the low noise amplifier input. Although the passive limiting systems limit the input power, they can cause high noise levels. Therefore, when low noise is required, the passive confinement system is not preferable.

Disclosure of Invention

In the present invention, an active limiting system is provided that is adapted to protect a low noise amplifier from a high power signal received from a signal input. The active limiting system comprises at least one first switch, the source of which is connected to the gate voltage; at least one first resistor connected between the gate and the source of the first switch; at least one second resistor connected between the drain voltage and the drain of the first switch; at least one second switch having a source connected to the drain voltage and a drain connected to a signal input; at least one third resistor connected between the drain of the first switch and the gate of the second switch; at least one first filter element blocking DC current/voltage and connected between the source of the second switch and ground.

In the present application, by using the first switch and the second switch, when a low power voltage signal is received from the signal input terminal, the signal is directly sent to the low noise amplifier. On the other hand, when a high power voltage signal is received from the signal input, the high power is reflected back. Thus, the low noise amplifier is protected from high power signals.

Object of the Invention

It is an object of the invention to provide an active limiting system which is suitable for protecting an amplifier from high input power levels.

It is another object of the invention to provide an active confinement system that can be produced in combination with a low noise amplifier on a single substrate.

Drawings

Fig. 1 is an exemplary circuit diagram of an active limiting system of the present application.

Fig. 2 is another exemplary circuit diagram of the active limiting system of the present application.

Fig. 3 is another exemplary circuit diagram of the active limiting system of the present application.

All parts shown in the figures are individually assigned reference numerals, the corresponding terms of which are as follows:

low Noise Amplifier (LNA)

First switch (T1)

Second switch (T2)

Amplifier transistor (Ta)

Signal input terminal (Ri)

Signal output terminal (Ro)

First resistor (R1)

Second resistor (R2)

Third resistor (R3)

Drain voltage (Vd)

Grid voltage (Vg)

Bias voltage (Vb)

First matching network (M1)

Second matching network (M2)

First filter element (b1)

Second filter element (b2)

Third filter element (b3)

Voltage damper (a)

Grid (g)

Source(s)

Drain electrode (d)

Detailed Description

The low noise amplifier amplifies the power level of the low power signal at a low noise level. In order to keep the noise level as low as possible, sensitive components are used in low noise amplifiers. Low noise amplifiers are susceptible to high power inputs due to the sensitive components. Thus, in the present application, an active limiting system has been developed that protects low noise amplifiers from high power inputs.

In fig. 1-2 an exemplary view of an active limiting system of the invention is shown, comprising at least one first switch (T1), preferably in the form of a HEMT, having at least one source(s), at least one gate (g) and at least one drain (d), the source(s) of which is connected to a gate voltage (Vg), wherein the electrical connection between the source(s) and the drain (d) of the first switch (T1) is controlled by the gate (g) to source(s) voltage of the first switch (T1); at least one first resistor (R1) connected between the gate (g) and the source(s) of the first switch (T1); at least one second resistor (R2) connected between the drain voltage (Vd) and the drain (d) of the first switch (T1); at least one second switch (T2), preferably in the form of a HEMT, having at least one source(s), at least one gate (g) and at least one drain (d), the source(s) of which is connected to the drain voltage (Vd) and the drain (d) of which is connected to the signal input (Ri), wherein the electrical connection between the source(s) and the drain (d) of the second switch (T2) is controlled by the gate (g) to source(s) voltage of the second switch (T2); at least one third resistor (R3) connected between the drain (d) of the first switch (T1) and the gate (g) of the second switch (T2); at least one first filter element (b1) (e.g., a capacitor) blocking DC current/voltage and connected between the source(s) of the second switch (T2) and ground.

In an exemplary embodiment of the application, a Low Noise Amplifier (LNA) is fed by a signal received from a signal input (Ri). In this embodiment, the gate (g) of the first switch (T1) is connected to the amplifier transistor (Ta) of the Low Noise Amplifier (LNA) through a first matching network (M1). The Low Noise Amplifier (LNA) may further include a drain voltage (Vd) and a gate voltage (Vg), a second matching network (M2), a second filter element (b2) (e.g., a capacitor) blocking the DC current/voltage, and a signal output (Ro), wherein a signal received from the signal input terminal (Ri) is amplified by the amplifier transistor (Ta) and output from the signal output terminal (Ro). In this embodiment, when the power level of the signal received from the signal input terminal (Ri) is low, no current flows through the first resistor (R1). Accordingly, the gate (g) voltage and the source(s) voltage of the first switch (T1) become equal to each other (i.e., the gate voltage (Vg)), and the first switch (T1) becomes an on state. In this state, the second switch (T2) becomes an open state, and the signal received from the signal input terminal (Ri) is not affected by the second switch (T2). On the other hand, when the power level of the signal received from the signal input terminal (Ri) is high, a current flows through the first resistor (R1). Therefore, the gate (g) voltage of the first switch (T1) becomes smaller than the source(s) voltage of the first switch (T1). This causes the first switch (T1) to become open. In this state, the second switch (T2) becomes on, and the entrance impedance of the Low Noise Amplifier (LNA) is disturbed. Thus, high power is reflected and a Low Noise Amplifier (LNA) is protected from the high power.

As shown in fig. 2, in the preferred embodiment of the present application, the active limiting system includes at least two second switches (T2) and at least two third resistors (R3). In this embodiment, by using a plurality of second switches (T2), the parasitic effect of the second switches (T2) is reduced.

In another preferred embodiment of the present application, the active limiting system comprises at least one voltage damper (a) between the second resistor (R2) and the drain (d) of the first switch (T1). The voltage damper (a) preferably comprises at least one, preferably two, diodes in order to generate a voltage difference between the second resistor (R2) and the drain (d) of the first switch (T1). Due to the above voltage difference, almost any input signal is immediately reflected when the drain voltage (Vd) becomes 0V. Thus, the high power protection of the system is improved.

In another preferred embodiment of the present application, the active limiting system comprises at least one third filter element (b3) (e.g. a capacitor) blocking DC current/voltage, connected between the signal input (Ri) and the drain (d) of the second switch (T2).

In the above-described embodiment, the first switch (T1), the second switch (T2), and the second resistor (R2) are connected to the drain voltage (Vd) and/or the gate voltage (Vg) of the Low Noise Amplifier (LNA). Thus, no other input is required for the operation of the active restraint system. Also, the active limiting system and the Low Noise Amplifier (LNA) can be placed on the same chip. In alternative embodiments, the active limiting system and the Low Noise Amplifier (LNA) may be different components (e.g., in the form of different chips).

Fig. 3 shows an alternative embodiment of the present application. In this embodiment, the active limiting system comprises at least one first switch (T1), preferably in the form of a HEMT, having at least one source(s), at least one gate (g) and at least one drain (d), the source(s) of which is connected to a bias voltage (Vb), wherein the electrical connection between the source(s) and the drain (d) of the first switch (T1) is controlled by the voltage from the gate (g) to the source(s) of the first switch (T1); at least one first resistor (R1) connected between the gate (g) of the first switch (T1) and a gate voltage (Vg); at least one second resistor (R2) connected between ground and the drain (d) of the first switch (T1); at least one second switch (T2), preferably in the form of a HEMT, having at least one source(s), at least one gate (g) and at least one drain (d), the source(s) of which is connected to ground and the drain (d) of which is connected to the signal input (Ri), wherein the electrical connection between the source(s) and the drain (d) of the second switch (T2) is controlled by the gate (g) to source(s) voltage of the second switch (T2); at least one third resistor (R3) connected between the drain (d) of the first switch (T1) and the gate (g) of the second switch (T2). In this embodiment, the gate (g) of the first switch (T1) is adapted to be connected to the amplifier transistor (Ta) of the Low Noise Amplifier (LNA) through a first matching network (M1). Preferably, as shown in fig. 3, the active limiting system comprises at least two second switches (T2) and at least two third resistors (R3). In this embodiment, by using a plurality of second switches (T2), the parasitic effect of the second switches (T2) is reduced.

In the present application, by using a first switch (T1) and a second switch (T2), when a low power voltage signal is received from a signal input (Ri), the signal is directly sent to a Low Noise Amplifier (LNA). On the other hand, when a high power voltage signal is received from the signal input (Ri), the high power is reflected back. Thus, a Low Noise Amplifier (LNA) may be protected from high power signals.