Temperature compensation circuit based on radio frequency power amplifier
阅读说明：本技术 基于射频功率放大器的温度补偿电路 (Temperature compensation circuit based on radio frequency power amplifier ) 是由 朱明皓 于 2019-11-12 设计创作，主要内容包括：本发明揭示了一种基于射频功率放大器的温度补偿电路,所述温度补偿电路包括第一温度补偿单元及第二温度补偿单元,所述第一温度补偿单元包括运算放大器及与运算放大器输出端并联的具有正温度系数的第四电阻T1,所述第二温度补偿单元包括串联于运算放大器输出端的分压电阻和二极管、及与二极管相连的射频功率放大器,所述二极管的压降Vd具有负温度系数。本发明中第二温度补偿单元对射频功率放大器进行线性温度补偿,第一温度补偿单元通过具有正温度系数的电阻搭建电路进行非线性温度补偿,采用两种温度补偿相结合的方式,对射频功率放大器的偏置电压进行温度补偿,以提高射频功率放大器在不同温度下增益的线性度。(The invention discloses temperature compensation circuits based on radio frequency power amplifiers, which comprise a th temperature compensation unit and a second temperature compensation unit, wherein the th temperature compensation unit comprises an operational amplifier and a fourth resistor T1 which is connected with the output end of the operational amplifier in parallel and has a positive temperature coefficient, the second temperature compensation unit comprises a divider resistor and a diode which are connected with the output end of the operational amplifier in series, and a radio frequency power amplifier which is connected with the diode, wherein a voltage drop Vd of the diode has a negative temperature coefficient.)
The temperature compensation circuit based on the radio frequency power amplifier is characterized in that the temperature compensation circuit comprises a th temperature compensation unit and a second temperature compensation unit, the th temperature compensation unit comprises an operational amplifier and a fourth resistor T1 which is connected with the output end of the operational amplifier in parallel and has a positive temperature coefficient, the second temperature compensation unit comprises a divider resistor and a diode which are connected with the output end of the operational amplifier in series and a radio frequency power amplifier which is connected with the diode, and the voltage drop Vd of the diode has a negative temperature coefficient.
2. The RF power amplifier-based temperature compensation circuit of claim 1, wherein the positive input terminal of the operational amplifier is connected to a reference voltage Vref, the fourth resistor T1 is connected to the output terminal and the negative input terminal of the operational amplifier, respectively, and the output voltage of the th temperature compensation unit is Vs.
3. The temperature compensation circuit of claim 2, wherein the negative input terminal of the operational amplifier is connected to the third resistor R3 and then grounded.
4. The temperature compensation circuit of claim 3, wherein the output voltage of the th temperature compensation unit is:
5. the RF power amplifier-based temperature compensation circuit of claim 4, wherein the second temperature compensation unit comprises a th resistor R1, a diode D1 and a second resistor R2 electrically connected between the output terminal of the operational amplifier and GND, a second inductor L2 and an RF power amplifier M1 electrically connected between a power supply VCC and GND, and a th inductor L1 electrically connected between the RF power amplifier M1 and the diode D1.
6. The RF power amplifier based temperature compensation circuit of claim 5, wherein the bias voltage of the RF power amplifier is:
7. the rf power amplifier based temperature compensation circuit according to claim 1, wherein the fourth resistor T1 is a thermistor with positive temperature coefficient.
8. The temperature compensation circuit of claim 6, wherein the fourth resistor has a resistance of T1 ═ Rt × eβTThe voltage drop of the diode is Vd ═ V0 × (1- α T), wherein α and β are constants, T is temperature, and Rt and V0 do not change along with the temperature.
9. The radio frequency power amplifier based temperature compensation circuit according to claim 8, wherein the bias voltage Vg and the temperature T of the radio frequency power amplifier satisfy the following relationship:
10. the radio frequency power amplifier based temperature compensation circuit according to claim 5, wherein the diode D1 is or more diodes arranged in series.
Technical Field
The invention belongs to the technical field of radio frequency power devices, and particularly relates to temperature compensation circuits based on a radio frequency power amplifier.
Background
Radio Frequency Power Amplifier (RFPA) is a main part of a transmitting system, in a front-stage circuit of a transmitter, the power of a radio frequency signal generated by a modulation oscillation circuit is small, and the radio frequency signal needs to be fed to an antenna to be radiated after enough radio frequency power is obtained through series of amplifiers (a buffer stage, an intermediate amplifier stage and a final power amplifier stage).
The rf power Amplifier usually needs to be provided With a corresponding Temperature Compensation Circuit, for example, in the prior art, in an article "X-Band MMICPower Amplifier With an On Chip Temperature Compensation-Compensation Circuit" published in IEEE Transactions On Microwave Theory and Techniques 12 th 2001, schemes adopting On-Chip Temperature Compensation are disclosed, which shows that the Gain (Gain) of the rf power Amplifier varies With Temperature (T) and bias voltage (Vg) (as shown in fig. 1), and in order to ensure that the Amplifier has -like gains at-20 ℃ and 70 ℃, Vg needs to be increased by 0.4V With Temperature.
Disclosure of Invention
Accordingly, the present invention is directed to temperature compensation circuits for rf power amplifiers, so as to improve the linearity of the gain of the rf power amplifier at different temperatures.
In order to achieve the above object, an embodiment of the present invention provides the following technical solutions:
A temperature compensation circuit based on RF power amplifier, the temperature compensation circuit includes temperature compensation unit and second temperature compensation unit, the temperature compensation unit includes operational amplifier and the fourth resistance T1 with positive temperature coefficient that is connected with the operational amplifier output end in parallel, the second temperature compensation unit includes the divider resistance and diode that are connected in series with the operational amplifier output end, and the RF power amplifier that is connected with the diode, the voltage drop Vd of the diode has negative temperature coefficient.
in the embodiment, the positive input terminal of the operational amplifier is connected to the reference voltage Vref, the fourth resistor T1 is connected to the output terminal and the negative input terminal of the operational amplifier, respectively, and the output voltage of the temperature compensation unit is Vs.
, the negative input terminal of the operational amplifier is connected to the third resistor R3 and then grounded.
in an embodiment, the output voltage of the th temperature compensation unit is:
in the embodiment, the second temperature compensation unit includes a resistor R1, a diode D1 and a second resistor R2 electrically connected between the output terminal of the operational amplifier and GND, a second inductor L2 and a radio frequency power amplifier M1 electrically connected between the power supply VCC and GND, and an inductor L1 electrically connected between the radio frequency power amplifier M1 and the diode D1.
in an embodiment, the bias voltage of the rf power amplifier is:
, the fourth resistor T1 is a thermistor with a positive temperature coefficient.
, the fourth resistor has a resistance T1 ═ Rt × eβTThe voltage drop of the diode is Vd ═ V0 × (1- α T), wherein α and β are constants, T is temperature, and Rt and V0 do not change along with the temperature.
in the embodiment, the bias voltage Vg and the temperature T of the rf power amplifier satisfy the following relationship:
, the diode D1 is or more diodes arranged in series.
Compared with the prior art, the invention has the following advantages:
the second temperature compensation unit is used for performing linear temperature compensation on the radio frequency power amplifier, the th temperature compensation unit is used for performing nonlinear temperature compensation through a resistance building circuit with a positive temperature coefficient, and the bias voltage of the radio frequency power amplifier is subjected to temperature compensation in a mode of combining the two temperature compensations, so that the gain linearity of the radio frequency power amplifier at different temperatures is improved.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only the embodiments described in the present application, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a graph of the variation of Gain (Gain) of a radio frequency power amplifier with temperature (T) and bias voltage (Vg) in the prior art;
FIG. 2 is a schematic diagram of a prior art temperature compensation circuit;
FIG. 3 is a graph showing the variation of Gain (Gain) of the RF power amplifier with temperature (T) and bias voltage (Vg) after the temperature compensation circuit in FIG. 2 is adopted;
FIG. 4 is a schematic diagram of a temperature compensation circuit in an embodiment of the invention.
Detailed Description
The present invention will be described in detail below with reference to embodiments shown in the drawings. The embodiments are not intended to limit the present invention, and structural, methodological, or functional changes made by those skilled in the art according to the embodiments are included in the scope of the present invention.
The invention discloses an temperature compensation circuit based on a radio frequency power amplifier, which comprises a temperature compensation unit and a second temperature compensation unit, wherein the temperature compensation unit comprises an operational amplifier and a fourth resistor T1 which is connected with the output end of the operational amplifier in parallel and has a positive temperature coefficient, the second temperature compensation unit comprises a divider resistor and a diode which are connected with the output end of the operational amplifier in series, and the radio frequency power amplifier which is connected with the diode, and the voltage drop Vd of the diode has a negative temperature coefficient.
The temperature compensation circuit in the invention combines the th temperature compensation unit and the second temperature compensation unit to perform temperature compensation on the bias voltage of the radio frequency power amplifier so as to ensure that the gain of the radio frequency power amplifier is at different temperatures, and the compensation method considers that the gain of the radio frequency power amplifier is nonlinear to the temperature, so that the scheme of combining the th temperature compensation unit and the second temperature compensation unit is adopted to improve the linearity of the gain of the radio frequency power amplifier at different temperatures.
The invention is further illustrated in with reference to specific examples.
Referring to fig. 4, in an embodiment of the temperature compensation circuit of the present invention based on an rf power amplifier, the temperature compensation circuit includes a th
The th
Specifically, the positive input terminal of the operational amplifier OPA is connected to a reference voltage Vref, the reference voltage Vref is a reference voltage and does not change with temperature, the fourth resistor T1 is connected to the output terminal and the negative input terminal of the operational amplifier OPA, respectively, the output voltage of the temperature compensation unit is Vs, and the negative input terminal of the operational amplifier OPA is connected to the third resistor R3 and then grounded.
According to KVL law, the output voltage of the th temperature compensation unit is:
specifically, the second
The bias voltage of the rf power amplifier in this embodiment is:
preferably, the fourth resistor T1 in this embodiment is a thermistor with positive temperature coefficient, and the resistance value of the fourth resistor T1 is Rt × eβTThe voltage drop of the diode is Vd ═ V0 × (1- α T), wherein α and β are constants, T is temperature, and Rt and V0 do not change along with the temperature.
Therefore, the bias voltage Vg and the temperature T of the rf power amplifier in this embodiment satisfy the following relationship:
the on-chip compensation circuit in this embodiment is similar to the prior art, and Vs generates a voltage for the off-chip compensation circuit, which is provided to the on-chip compensation circuit instead of VCC in the prior art.
By designing a proper resistance value, the relationship between Vg and temperature T is close to linear at room temperature and close to exponential at high temperature (T >50 ℃).
For example, the fourth resistor T1 in this embodiment is a thermistor with T1 ═ 2Kohm @20 ℃, and by designing reasonable values of Vref, R1, R2, and R3, Vg temperature coefficients of +7.4mV/° c @20 ℃ and 20mV/° c @70 ℃ can be obtained, which is obviously better than the linear compensation in fig. 3 in responsiveness.
Preferably, in the invention, Vd can also be increased by serially connecting a diode D1 to increase the temperature coefficient of Vg.
The Radio Frequency Power Amplifier (RFPA) in the invention includes, but is not limited to, a Radio Frequency Power Amplifier (RFPA) realized based on processes such as a complementary metal oxide semiconductor transistor (CMOS), a Heterojunction Bipolar Transistor (HBT), a High Electron Mobility Transistor (HEMT), and the like, and of course, the invention is also applicable to amplifiers such as a Low Noise Amplifier (LNA), and the like, and all schemes of performing linear compensation by using the temperature compensation circuit belong to the protection scope of the invention.
According to the technical scheme, the invention has the following beneficial effects:
the second temperature compensation unit is used for performing linear temperature compensation on the radio frequency power amplifier, the th temperature compensation unit is used for performing nonlinear temperature compensation through a resistance building circuit with a positive temperature coefficient, and the bias voltage of the radio frequency power amplifier is subjected to temperature compensation in a mode of combining the two temperature compensations, so that the gain linearity of the radio frequency power amplifier at different temperatures is improved.
It will thus be seen that the embodiments are illustrative and not restrictive in any respect point of view, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
Furthermore, it should be understood that although the present description has been described in terms of examples, not every example contains independent solutions, and such description is merely for clarity, and those skilled in the art should take the description as whole, and the solutions in the examples can be combined as appropriate to form other embodiments understood by those skilled in the art.
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