CN205584141U

CN205584141U - High linearity broadband amplifier

Info

Publication number: CN205584141U
Application number: CN201620157228.6U
Authority: CN
Inventors: 曹然
Original assignee: SUZHOU RONGXIN MICROELECTRONICS Co Ltd
Current assignee: SUZHOU RONGXIN MICROELECTRONICS Co Ltd
Priority date: 2016-03-02
Filing date: 2016-03-02
Publication date: 2016-09-14
Anticipated expiration: 2026-03-02

Abstract

The utility model discloses a can maintain the gain of ideal and the high linearity broadband amplifier of the linearity at great incoming signal within range, include: cascode type amplifier circuit, with bias circuit, setting that cascode type amplifier circuit's input links to each other are in cascode type amplifier circuit's input, the static feedback circuit between the output and setting are in cascode type amplifier circuit's input, the dynamic feedback circuit between the output, these developments feedback circuit can adjust according to incoming signal's size dynamicly feedback resistance value between the input of cascode type amplifier circuit, the output. The utility model discloses be particularly useful for cable television's (CATV) transmission course and the radio frequency drive that fiber to the home.

Description

A kind of high linearity broadband amplifier

Technical field

This utility model relates to a kind of amplifier, refers more particularly to the broadband that a kind of input signal power is bigger Amplifier.

Background technology

Traditional amplifier circuit as shown in Figure 1, in order to reach bigger bandwidth, generally in input and defeated A feedback resistance R is introduced between going out_F.But, in a lot of application scenarios, such as cable television (CATV) Signal transmission or fiber-to-the-home radio-frequency driven, owing to the power bracket of input signal is relatively big, the most even can There is the dynamic range of tens dBm so that amplifier is easy to when big input signal saturated, thus affects The linearity index of output signal.In order to improve the linearity of amplifier, the method generally used is to amplify The emitter stage of device introduces a negative feedback resistor R_EImprove the linearity of amplifier, but, bearing of introducing is anti- Feed resistance R_EBring a negative effect, it may be assumed that reduce the gain of amplifier.Therefore, apply in reality In, generally require manual adjustment resistance R_EAnd R_FResistance so that amplifier is at bigger input reference signal In, maintain preferable gain and the linearity.

The method of this manual adjustment, it is desirable to amplifier integrated circuit has unnecessary pin, to peripheral control electricity Road uses, and this not only can increase the cost of integrated antenna package, also requires the control circuit outside configuration, this Under the trend seeking low cost application at present, often can not be received.It is true that if use The integrated circuit of SOT89 or other similar encapsulation only has three pins (input, export and ground), cannot at all The method realizing this outside regulation.

Utility model content

Technical problem to be solved in the utility model is: provide a kind of can in bigger input reference signal Maintain the high linearity broadband amplifier of preferable gain and the linearity.

For solving above-mentioned technical problem, the technical solution adopted in the utility model is: a kind of high linearity broadband Amplifier, including: cascode type amplifying circuit；

The biasing circuit being connected with the input of described cascode type amplifying circuit, it is that described cascode type amplifies Circuit provides bias voltage；

It is arranged on the static feedback resistance between the input of described cascode type amplifying circuit, outfan；

It is arranged on the dynamical feedback circuit between the input of described cascode type amplifying circuit, outfan, its effect It is: according to the size of input signal dynamically to regulate between the input of described cascode type amplifying circuit, outfan Feedback resistance value.

As a kind of preferred version, in described high linearity broadband amplifier, described dynamical feedback electricity The concrete structure on road includes: dynamically regulate audion, a pair i.e. upper offset resistance of biasing resistor and below-center offset electricity Resistance and a low-pass filtering electric capacity, the dynamically colelctor electrode of regulation audion and described cascode type amplifying circuit Outfan is connected with one end of upper offset resistance, and dynamically the emitter stage of regulation audion amplifies with described cascode type The input of circuit is connected with one end of below-center offset resistance, the respective other end of upper and lower biasing resistor be connected, And be connected with the dynamically base stage of regulation audion and the respective end of low-pass filtering electric capacity, low-pass filtering electric capacity another One end ground connection；Described static feedback circuit is static feedback resistance.

As a kind of preferred version, in described high linearity broadband amplifier, described cascode type amplifies Circuit is single transistor.

As a kind of preferred version, in described high linearity broadband amplifier, described cascode type amplifies Circuit is the transistor group of Darlington configuration.

As a kind of preferred version, in described high linearity broadband amplifier, described biasing circuit is Single resistance, resitstance voltage divider or automatic biasing structure.

The beneficial effects of the utility model are: this utility model is by adding one by transistor, biased electrical Resistance and the dynamical feedback circuit of low-pass filtering electric capacity composition, it is not necessary to extra pin and peripheral control circuits, real Show at bigger input reference signal, can dynamically regulate described amplifier according to the size of input signal Feedback resistance value, on the premise of not reducing whole amplifier gain, improve the linearity, and, fall Low application cost.

Accompanying drawing explanation

Fig. 1 is the electric principle assumption diagram of the broadband amplifier described in background technology.

Fig. 2 is the electric principle assumption diagram of broadband amplifier described in the utility model.

Fig. 3 is the actual measurement gain curve figure of two kinds of broadband amplifiers described in Fig. 1 and Fig. 2.

Detailed description of the invention

Below in conjunction with the accompanying drawings, the concrete real of high linearity broadband described in the utility model amplifier is described in detail Execute scheme:

As in figure 2 it is shown, a kind of high linearity broadband described in the utility model amplifier, including: by single NPN type triode Q1 constitute cascode type amplifying circuit 103, for audion Q1 provide bias voltage inclined Circuits 104, be arranged on the input of cascode type amplifying circuit 103, the outfan i.e. base stage of audion Q1 and The static feedback resistance R as static feedback circuit 102 between colelctor electrode_F, and be similarly disposed at cascode Dynamical feedback electricity between the input of type amplifying circuit 103, outfan i.e. base stage and the colelctor electrode of audion Q1 Road 101, the concrete structure of this dynamical feedback circuit 101 includes: NPN type dynamically regulate audion Q2, one To biasing resistor i.e. upper offset resistance R₁With below-center offset resistance R₂And a low-pass filtering electric capacity C_B, dynamically The colelctor electrode of regulation audion Q2 and the colelctor electrode of described audion Q1 and upper offset resistance R₁One end phase Even, the emitter stage of audion Q2 and the base stage of described audion Q1 and below-center offset resistance R are dynamically regulated₂One End is connected, upper and lower biasing resistor R₁And R₂The respective other end is connected and regulates audion Q2 with dynamic Base stage and low-pass filtering electric capacity C_BRespective end be connected, low-pass filtering electric capacity C_BOther end ground connection.

During actual application, described biasing circuit can use the differences such as single resistance, resitstance voltage divider, automatic biasing Structure；Described cascode type amplifying circuit 103 can be above-mentioned single audion Q1, it is also possible to be to reach The transistor group of spirit structure.

During real work, upper offset resistance R₁With below-center offset resistance R₂Composition resitstance voltage divider, for dynamically regulation Audion Q2 provides bias voltage；And, upper offset resistance R₁, below-center offset resistance R₂Also with low-pass filtering Electric capacity C_BForm a low pass filter, for the base voltage filtering of dynamically regulation audion Q2；By Fig. 3 It can be seen that the operating characteristic of dynamical feedback circuit 101 is equivalent to a variable resistance, its resistance is with amplification The increase of the power of device input signal and automatically reduce, with the reduction of power of amplifier input signal and automatic Increase.

In sum, preferred embodiment the most of the present utility model, not it is used for limiting this utility model The scope implemented, all according to the shape described in this utility model right, structure, feature and spirit institute Impartial change and the modification made, all should be included in right of the present utility model.

Claims

1. a high linearity broadband amplifier, including: cascode type amplifying circuit, it is characterised in that described High Linear broadband amplifier also include:

It is arranged on the static feedback circuit between the input of described cascode type amplifying circuit, outfan；

High linearity broadband the most according to claim 1 amplifier, it is characterised in that described is dynamic The concrete structure of feedback circuit includes: dynamically regulate audion, a pair i.e. upper offset resistance of biasing resistor and under Biasing resistor and a low-pass filtering electric capacity, dynamically the colelctor electrode of regulation audion amplifies with described cascode type The outfan of circuit is connected with one end of upper offset resistance, dynamically regulates the emitter stage of audion and described cascode The input of type amplifying circuit is connected with one end of below-center offset resistance, the respective other end of upper and lower biasing resistor It is connected and is connected with the dynamically base stage of regulation audion and the respective end of low-pass filtering electric capacity, low-pass filtering electricity The other end ground connection held；Described static feedback circuit is static feedback resistance.

High linearity broadband the most according to claim 2 amplifier, it is characterised in that described cascode Type amplifying circuit is single transistor.

High linearity broadband the most according to claim 2 amplifier, it is characterised in that described cascode Type amplifying circuit is the transistor group of Darlington configuration.

5. according to the high linearity broadband amplifier one of Claims 1-4 Suo Shu, it is characterised in that institute The biasing circuit stated is single resistance, resitstance voltage divider or automatic biasing structure.