CN102347745A

CN102347745A - Adaptive impedance matching circuit

Info

Publication number: CN102347745A
Application number: CN2010102438582A
Authority: CN
Inventors: 赵登; 陈陶陶
Original assignee: Ambit Microsystems Shanghai Ltd; Hon Hai Precision Industry Co Ltd
Current assignee: Ambit Microsystems Shanghai Ltd; Hon Hai Precision Industry Co Ltd
Priority date: 2010-08-04
Filing date: 2010-08-04
Publication date: 2012-02-08

Abstract

The invention discloses an adaptive impedance matching circuit applicable to a microwave circuit. The adaptive impedance matching circuit comprises an input end, an output end, a variable impedance circuit, a first directional coupler, a second directional coupler, a subtraction unit and a regulation unit, wherein the variable impedance circuit is connected between the input end and the output end and comprises a variable capacitor; the first directional coupler is used for measuring the input power of the input end; the second directional coupler is used for measuring the output power of the output end; the subtraction unit is used for calculating a difference value of the input power and the output power; and the regulation unit is used for regulating a bias voltage of the variable capacitor according to the difference value so as to change an impedance value of the variable impedance circuit to realize timely impedance matching. When the output power changes along with the change of a load, the impedance of the variable impedance circuit can be automatically regulated according to the power difference value of the input end and the output end, so that the timely impedance matching of the load and a pre-stage circuit is realized.

Description

The self adaptation impedance matching circuit

Technical field

The present invention relates to a kind of microwave circuit, particularly a kind of self adaptation impedance matching circuit.

Background technology

The impedance of load must for this reason, all be designed with impedance matching circuit with the impedance matching of front stage circuits so that the performance of microwave circuit reaches optimum in the microwave circuit in the microwave circuit.The resistance value of existing impedance matching circuit is fixed; Yet for the more and more abundanter microwave product of function, its load in use can change within the specific limits; Will cause the mismatch of impedance matching circuit like this, thereby influence the performance of microwave circuit.

Summary of the invention

In view of this, be necessary to provide a kind of self adaptation impedance matching circuit, it can adjust its impedance to realize in good time impedance matching automatically according to the change of load.

A kind of self adaptation impedance matching circuit, it comprises an input, an output, a variable impedance circuit, first, second directional coupler, subtrator and regulon.Variable impedance circuit is connected between this input and this output, and said variable impedance circuit comprises a variable capacitance.First directional coupler is connected between this variable impedance circuit and this input, is used to measure the input power of this input.Second directional coupler is connected between this variable impedance circuit and this output, is used to measure the power output of this output.Subtrator is connected between this first directional coupler and this second directional coupler, is used to calculate the difference of this input power and this power output.Regulon is connected between this subtrator and this variable impedance circuit, is used for regulating according to this difference the bias voltage of this variable capacitance, thereby the resistance value that changes this variable impedance circuit is to realize in good time impedance matching.

When causing the power output change owing to load variations, the present invention can regulate the impedance of variable impedance circuit automatically according to the power difference of input and output, thereby realizes the in good time impedance matching of load and front stage circuits.

Description of drawings

Fig. 1 is the circuit module figure of the self adaptation impedance matching circuit of embodiment of the present invention.

Fig. 2 is the circuit diagram of the variable impedance circuit of the self adaptation impedance circuit among Fig. 1.

The main element symbol description

Front stage circuits 10

Self adaptation impedance matching circuit 20

Input 21

Directional coupler

22,24

Variable impedance circuit 23

Input 231

Fixed capacity 232,233

Inductance element 234

Output 235

Earth terminal 236

Variable capacitance 237

Resistance 238

Adjustable side 239

Output 25

AC/DC (AC/DC) modular converter 26,28

Regulon 27

Power supply 271

Amplifier

29,31

Subtrator 30

Load 40

Power P 1, P2

Difference S

Embodiment

To combine accompanying drawing below, the present invention will be done further detailed description.

Please join Fig. 1, Fig. 2, a kind of self adaptation impedance matching circuit 20 that embodiment of the present invention provides.This self adaptation impedance matching circuit 20 comprises an input 21 and an output 25, and said input 21 is coupled to a front stage circuits 10, and said output 25 is coupled to a load 40, and the impedance meeting of this load 40 is change within the specific limits in use.

This self adaptation impedance matching circuit 20 comprises variable impedance circuit 23,

directional coupler

22,24, AC/DC (AC/DC)

modular converter

26,28,

amplifier

29,31, subtrator 30, regulon 27 and power supply 271.The input of directional coupler 22 is connected to the input 21 of self adaptation impedance matching circuit 20; The output of directional coupler 22 connects the input 231 of variable impedance circuit 23; The input of directional coupler 23 connects the output 235 of variable impedance circuit 23, and the output of directional coupler 23 connects this output 25.The coupled end of directional coupler 22 connects the input of AC/DC modular converter 26, and the output of AC/DC modular converter 26 connects the input of amplifier 29, and the output of amplifier 29 connects an input of subtrator 30; The coupled end of directional coupler 24 connects the input of AC/DC modular converter 28, and the output of AC/DC modular converter 28 connects the input of amplifier 31, and the output of amplifier 31 connects another input of subtrator 30.The output of subtrator 30 is connected to the input of regulon 27, and the output of regulon 27 is connected to the adjustable side 239 of variable impedance circuit 23.Power supply 271 is connected with regulon 27 to provide power supply to regulon 27.

Directional coupler 22 is used to measure the power P 1 of impedance matching circuit 20 inputs 21, the i.e. power output of front stage circuits 10.In this execution mode, the size of power is with the alternating current value representation.Power signal P1 converts direct current signal to through AC/DC modular converter 26, is input to subtrator 30 after amplifying through amplifier 29.Certainly, in other embodiments, also available other signals of telecommunication characterize this power P 1, for example voltage.

Directional coupler 24 is used to measure the power P 2 of the output 25 of impedance matching circuit 20, promptly is applied to the power in the load 40.Power signal P2 converts direct current signal to through AC/DC modular converter 28, is input to subtrator 30 after amplifying through amplifier 31.

Subtrator 30 is used to calculate the difference S of power P 1 and P2, and this difference S is outputed to regulon 27.Regulon 27 is used for regulating according to this difference S the resistance value of variable impedance circuit 23, equates until P1 and P2.In this execution mode, power supply 271 is regulated required voltage for regulon 27 provides, and regulon 27 is applied to the bias voltage on the variable impedance circuit 23 through adjusting, changes the resistance value of variable impedance circuit 23.

Above-mentioned directional coupler, AC/DC modular converter, amplifier, subtrator, regulon are that those skilled in the art know, and do not do introduction at this concrete structure to above-mentioned parts.

Variable impedance circuit 23 comprises fixed capacity 232,233, inductance element 234, variable capacitance 237 and resistance 238.Inductance element 234 1 ends are connected to the output 235 of variable impedance circuit 23, and the other end is connected to an end of fixed capacity 233.One end of fixed capacity 232 is connected to the input 231 of variable impedance circuit 23.The other end of fixed capacity 232,233 is connected with each other.Variable capacitance 237 1 ends are connected in fixed capacity 232, between 233, the other end links to each other with earth terminal 236.Resistance 238 1 ends are connected in fixed capacity 232, between 233, the other end is connected to the adjustable side 239 of variable impedance circuit 23.

Inductance element 234 is used to form a lc circuit with variable capacitance 237, applies the capacitance that bias voltage changes electric capacity 237, just can change the impedance of above-mentioned lc circuit.Resistance 238 is used to receive the voltage that applies from regulon 27 and also this voltage is imposed on variable capacitance 237.Fixed capacity 232,233 is used for the DC component of isolated circuit, can not be applied in the load 40 to guarantee it.

Electric capacity, inductance, the concrete value of resistance can be confirmed according to actual conditions; For example; When the resistance of load 40 was designed to 50 ohm (ohm), the inductance value of inductance element 234 can be designed to 469 microhenries (uH), and the capacitance scope of variable capacitance 237 can be designed to 5.8 microfarads (uF)～0.37 microfarads (uF); Accordingly; The bias voltage scope that is applied on the variable capacitance 237 is 0～40 volt of (V) direct current (DC), and the resistance of resistance 238 is 0 ohm (ohm), and the electric capacity of fixed capacity 232,233 is respectively 50 pico farads (pF).This moment, the impedance ranges of impedance matching circuit 20 was (0.1-j2.9)～(34.1-j33.7) ohm (ohm).

In addition, those skilled in the art can do other variation in spirit of the present invention, and still, all variations of doing according to spirit of the present invention all should be included within the present invention's scope required for protection.

Claims

1. self adaptation impedance matching circuit, it comprises

One input;

One output;

One is connected in the variable impedance circuit between this input and this output, and this variable impedance circuit comprises a variable capacitance;

One is connected in first directional coupler between this variable impedance circuit and this input, is used to measure the input power of this input;

One is connected in second directional coupler between this variable impedance circuit and this output, is used to measure the power output of this output;

One is connected in the subtrator between this first directional coupler and this second directional coupler, is used to calculate the difference of this input power and this power output; And

One is connected in the regulon between this subtrator and this variable impedance circuit, is used for regulating according to this difference the bias voltage of this variable capacitance, thereby the resistance value that changes this variable impedance circuit is to realize in good time impedance matching.

2. self adaptation impedance matching circuit as claimed in claim 1; It is characterized in that: this first directional coupler is represented with AC signal with the power that this second directional coupler records; This self adaptation impedance matching circuit comprises also and is connected in the first AC/DC modular converter between this first directional coupler and this subtrator and is connected in the second AC/DC modular converter between this second directional coupler and this subtrator that the AC signal that is used for respectively this first directional coupler and this second directional coupler being recorded converts direct current signal into.

3. self adaptation impedance matching circuit as claimed in claim 2; It is characterized in that: also comprise first amplifier that is connected between this first AC/DC modular converter and this subtrator; And being connected in second amplifier between this second AC/DC modular converter and this subtrator, the signal after the power signal that is used for respectively this first directional coupler and this second directional coupler being recorded amplifies and will amplify outputs to this subtrator.

4. self adaptation impedance matching circuit as claimed in claim 1 is characterized in that: comprise that also one is connected to the power supply of this regulon, be used to regulon power supply is provided.

5. self adaptation impedance matching circuit as claimed in claim 1; It is characterized in that: this variable impedance circuit also comprises first fixed capacity and second fixed capacity; This first fixed capacity, one end is connected with this input; This second fixed capacity, one end is connected with this output, and the other end of this first fixed capacity and this second fixed capacity is interconnected each other.

6. self adaptation impedance matching circuit as claimed in claim 5 is characterized in that: this variable capacitance one end ground connection, the other end are connected between this first fixed capacity and this second fixed capacity and further are connected to this regulon.

7. self adaptation impedance matching circuit as claimed in claim 6 is characterized in that: this variable impedance circuit also comprises a resistance, and this variable capacitance is connected to this regulon through this resistance.

8. self adaptation impedance matching circuit as claimed in claim 5 is characterized in that: this variable impedance circuit also comprises an inductance, and this second fixed capacity is connected to this output through this inductance.

9. self adaptation impedance matching circuit as claimed in claim 1 is characterized in that: the capacitance scope of this variable capacitance is 5.8 microfarads (uF)～0.37 microfarads (uF).

10. self adaptation impedance matching circuit as claimed in claim 1 is characterized in that: the resistance value scope of this variable impedance circuit is (0.1-j2.9)～(34.1-j33.7) ohm (ohm).