CN2788449Y

CN2788449Y - RF Power Amplifier Bias Circuit

Info

Publication number: CN2788449Y
Application number: CN 200520011782
Authority: CN
Inventors: 杨建生; 蔡坤洲
Original assignee: Longfor Technology Co ltd
Current assignee: Longfor Technology Co ltd
Priority date: 2005-04-13
Filing date: 2005-04-13
Publication date: 2006-06-14
Anticipated expiration: 2015-04-13

Abstract

The utility model discloses a radio frequency power amplifier bias circuit, which includes a bias circuit and an impedance matching circuit. The bias circuit is used to provide a stable working bias voltage for the radio frequency power amplifier, and the impedance matching circuit is used to connect an antenna and perform impedance matching. Thus, the current and power of the radio frequency power amplifier can maintain their linear stability at different temperatures, and the radio frequency power amplifier can achieve the effects of low current loss and high efficiency.

Description

The radio-frequency power amplifier bias circuit

Technical field:

The utility model relates to a kind of radio-frequency power amplifier bias circuit.

Background technology:

General existing bias circuit as shown in Figure 1, this bias circuit 4 provides the first transistor 41 bias voltages, is made up of a transistor seconds that is connected with this first transistor 41 42, the 3rd transistor 43 that is connected with this transistor seconds 42 and the 4th transistor 44 that is connected with the 3rd transistor 43; And the 3rd transistor 43 is connected with a resistance 45, and has a resistance 46 between this first, second transistor (41,42).

And when using, the electric current I of this bias circuit 4 ₁When in a single day this temperature rises, this electric current I ₁Then rising that can be relative, at this moment, this electric current I ₂Also can be because of electric current I ₁Rising and rise, this moment, total current I also can rise, and then caused operating current to be difficult to control, instability also can make angle of flow instability, influence the linearity and the efficient of power amplifier, other is as input signal power P _InRising can make the V of radio-frequency power amplifier the first transistor 41 bias voltages _BEDescend, and make total current I ascensional range excessive, and then cause the angle of flow to become big, cause the change of the angle of flow and influence the linearity of power amplifier.Therefore, it is required when reality is used generally can't to meet the user.

The utility model content:

Technical problem to be solved in the utility model is, at existing technical deficiency, a kind of temperature-compensating mechanism of having is provided, can make this radio-frequency power amplifier under different temperatures, keep the stable of its quiescent current and the linearity, and can reduce the quiescent current of radio-frequency power amplifier, and reach the radio-frequency power amplifier bias circuit of high power and high efficiency linear amplifier.

In order to solve the problems of the technologies described above, the technical scheme that the utility model adopted is: a kind of radio-frequency power amplifier bias circuit, this circuit includes one and is connected with bias circuit in order to the bias circuit and that this radio-frequency power amplifier steady operation bias voltage is provided, with the impedance matching circuit of using do impedance matching with antenna.

Compared with prior art, the utility model has the advantages that: can make the electric current of this radio-frequency power amplifier under different temperature, keep the stable of its linearity, and can make radio-frequency power amplifier keep its low current loss with power, and the height of increasing work efficiency.

Description of drawings:

Fig. 1 is existing bias circuit figure.

Fig. 2 is a circuit diagram of the present utility model.

Fig. 3 is the utility model and traditional quiescent current comparison schematic diagram under different temperatures.

Among the figure: a----tradition b----the utility model

Fig. 4 is the circuit diagram of another embodiment of the present utility model.

The figure number explanation:

Bias circuit 4

The first transistor 41

Transistor seconds 42

The 3rd transistor 43

The 4th transistor 44

Resistance 45,46

Bias circuit 1

The first transistor 11

Transistor seconds 12

The 3rd transistor 13

The 4th transistor 14

The 5th transistor 15

Resistance

16,17

First electric capacity 18

Impedance matching circuit 2

Antenna 21

Second electric capacity 22

Radio-frequency coil 23

Resistance 3

Embodiment:

See also Fig. 2-shown in Figure 3, a kind of radio-frequency power amplifier bias circuit, it is made up of a bias circuit 1 and an impedance matching circuit 2, can make the quiescent current of this radio-frequency power amplifier keep stable under different temperature.

The above-mentioned bias circuit of carrying 1 is in order to provide this radio-frequency power amplifier stable working bias voltage, this bias circuit 1 is by a first transistor 11, one transistor seconds 12 that is connected with this first transistor 11, one the 3rd transistor 13 that is connected with this transistor seconds 12 and the 5th transistor 15, the and the one and the 3rd, the 5th transistor (13,15) the 4th transistor 14 of Lian Jieing is formed, and this first transistor 11 uses for rate amplifier as one, and be connected with one first electric capacity 18 in this first transistor 11, this transistor seconds 12 uses as a buffer transistor, the 3rd, the 4th transistor (13,14) use as a reference diode, the 5th transistor 15 is as a negative feedback path that electric current is provided, and the 3rd transistor 13 is connected with a resistance 16, and is provided with a resistance 17 between this first transistor 11 and transistor seconds 12.

This impedance matching circuit 2 is connected with above-mentioned bias circuit 1, this impedance matching circuit 2 is connected with an antenna 21, be in order to making the usefulness of impedance matching with antenna 21, these impedance matching circuit 2 collocation are connected with one second electric capacity 22 and radio-frequency coil 23, use with bias circuit 1 to be connected.In this way, constitute a brand-new radio-frequency power amplifier bias circuit by said structure.

When running, make a radiofrequency signal transfer to this first transistor 11 and export the most the first transistor 11 of power amplifier of suitable operating current through bias circuit 1 through first electric capacity 18, and cooperate this radio-frequency coil 23 that the amplifying signal electric current is sent to impedance matching circuit 2 through second electric capacity 22, make this impedance matching circuit 2 can with the usefulness of antenna 21 as impedance matching; And after electric current transfers to this bias circuit 1 through first electric capacity 18, and when the electric current Vin of this power amplifier is risen, then can make its V by the effect of this first transistor 11 _BEDescend, as this V _BEThis electric current I during decline ₄Promptly can rise, but because this electric current I ₄Come from electric current I ₁, this moment this electric current I ₁Then can descend, so when this electric current I ₁This electric current I during decline ₄Also can descend thereupon, can make the electric current of this radio-frequency power amplifier under different temperature, keep the stable of its linearity with power, and it is low to make this radio-frequency power amplifier reach when not using electric current, the effect that the Use Limitation rate is high, and then make this angle of flow reach effect stable, undistorted and that efficient is high, as shown in Figure 3; Therefore, when this bias circuit cooperates radio-frequency power amplifier to use, be somebody's turn to do the suitable selection bias point of the first transistor 11 meeting processes, and constitute a class ab ammplifier, and reach high efficiency function as power amplifier.

See also shown in Figure 4ly, be the circuit diagram of another embodiment.As shown in the figure: the utility model is except that above-mentioned circuit kenel, also can be in this first transistor 11, transistor seconds 12, the 3rd transistor 13, can be connected with resistance 3 respectively between the 4th transistor 14 and the 5th transistor 15, and since the 5th transistor 15 as a negative feedback path that electric current is provided, therefore, this resistance 3 can be in order to adjust the relative ratio of electric current, and the back coupling amount of Control current, because when this radio-frequency power amplifier uses, its power supply is beated, can make this bias circuit cause the phenomenon of electric current change to take place, and then make the gain of this electric current produce change, or because electric current causes saturated very little, so suitable regulation and control resistance 3 can be controlled suitable electric current, and then reaches the linearity of improving radio-frequency power amplifier, and makes electric current more stable.

In sum, the utility model radio-frequency power amplifier bias circuit can make the electric current of this radio-frequency power amplifier keep the stable of its linearity with power under different temperature, and it is low to make this radio-frequency power amplifier reach when not using electric current, the effect that the Use Limitation rate is high.

Claims

1. A radio frequency power amplifier bias circuit, characterized in that: the circuit includes:

A bias circuit, which is used to provide a stable working bias voltage for the radio frequency power amplifier;

An impedance matching circuit, the impedance matching circuit is connected with the bias circuit, and used for impedance matching with an antenna.

2. The RF power amplifier bias circuit according to claim 1, characterized in that: the bias circuit is composed of a first transistor, a second transistor connected to the first transistor, and a second transistor connected to the second transistor. The third transistor is composed of the fifth transistor and a fourth transistor connected with the third and fifth transistors.

3. The RF power amplifier bias circuit according to claim 2, wherein the first transistor is used as a power amplifier.

4. The RF power amplifier bias circuit according to claim 2, wherein the first transistor is connected to a first capacitor.

5. The RF power amplifier bias circuit according to claim 2, wherein the second transistor is a buffer transistor.

6. The RF power amplifier bias circuit according to claim 2, wherein the third and fourth transistors are used as a reference diode.

7. The RF power amplifier bias circuit according to claim 2, wherein the fifth transistor serves as a negative feedback path for supplying current.

8. The RF power amplifier bias circuit according to claim 2, wherein the third transistor is connected with a resistor.

9. The radio frequency power amplifier bias circuit according to claim 2, wherein a resistor is arranged between the first transistor and the second transistor.

10. The radio frequency power amplifier bias circuit according to claim 2, characterized in that: the first transistor, the second transistor, the third transistor, the fourth transistor and the fifth transistor can be used according to the actual use. Resistors are respectively connected to adjust the amount of current feedback.

11. The RF power amplifier bias circuit according to claim 1, wherein the impedance matching circuit is connected with a second capacitor and a radio frequency coil connected to the bias circuit.

12. The radio frequency power amplifier bias circuit according to claim 1, wherein the impedance matching circuit is connected with an antenna.