JPWO2008044276A1 - Power amplifier - Google Patents

Abstract

A high-efficiency and low-distortion power amplifier that can be applied to multi-mode terminals that support various modulation systems. In this power amplification device, when a baseband signal in the RF band is input to the coupler (101), the envelope detector (102) is insulated from the coupler (101) and detects the envelope information of the baseband signal. The peak detection unit (104) calculates peak power from the envelope information, and the average processing unit (103) calculates average power within a predetermined time from the envelope information. The amplifier control unit (109) changes the power supply voltage of the transistor (107) and the load impedance viewed from the output matching circuit (108) based on the peak power and the average power. Further, based on the average power, the gain of the variable gain amplifier is adjusted in accordance with the variation of the amplification factor of the transistor (107) so that the total gain as the power amplifier becomes constant.

Description

  The present invention relates to a power amplifying apparatus that is applied to a mobile communication terminal or the like and amplifies an RF (Radio Frequency) signal.

  Conventionally, in amplifiers used in mobile communication terminals that perform transmission power control, a method of performing power supply voltage control and load impedance control of an amplifier together as a method of realizing high efficiency with low distortion and a wide dynamic range. (For example, refer to Patent Document 1). FIG. 1 is a block diagram showing an example of a conventional power amplifier. As shown in FIG. 1, this power amplifying apparatus mainly includes an input power sensor 1, a coupler 2, a variable gain amplifier 3, an input matching circuit 4, a transistor 5, an output matching circuit 6, and a power supply circuit 7. It has become.

  In this power amplification device, when the input power sensor 1 detects the average power of an RF (Radio Frequency) band input signal supplied to the variable gain amplifier 3 and determines that the average power is small, the power supply circuit 7 The DC voltage supplied to the transistor 5 is lowered, and at the same time, the load impedance control signal is transmitted from the power supply circuit 7 to the output matching circuit 6 so as to increase the load impedance, thereby performing impedance control. In this way, the amplitude of the output voltage can be increased by increasing the load impedance, and as a result, the distortion characteristics can be improved.

  On the other hand, when the input power sensor 1 determines that the average power of the input signal supplied to the variable gain amplifier 3 is large, the DC voltage supplied from the power supply circuit 7 to the transistor 5 is increased and the load impedance is decreased. As a result, the amplitude of the output voltage can be made smaller than the breakdown voltage of the transistor 5 even at high power, and it is possible to perform highly efficient power amplification with less distortion while improving reliability. .

  Here, the reason why low distortion and high efficiency can be realized by performing power supply voltage control and load impedance control of the transistor amplifier together will be described. FIG. 2 is a characteristic diagram showing voltage-current characteristics and load characteristics of a transistor amplifier. FIG. 2A shows the case where power supply voltage control is performed when the average power of the input signal is large, and FIG. 2B shows the average of the input signal. When the power supply voltage control is performed when the power is low, (c) shows the respective characteristics when the power supply voltage control and the load impedance control are performed when the average power of the input signal is small. In each characteristic diagram, the horizontal axis represents the drain voltage (vd) of the transistor amplifier, and the vertical axis represents the drain current (id).

  As shown in FIG. 2A, when the power supply voltage control is performed when the average power of the input signal is large, a good linearity is obtained for the amplification characteristic as in the load line (A). However, when the power supply voltage control is performed when the average power of the input signal is small, load characteristics such as the load line (B) shown in FIG. 2B are obtained, so that voltage (vd) -current (id) The linearity is lost in the rising region, and the distortion characteristics deteriorate. That is, the linearity is deteriorated simply by controlling the power supply voltage according to the average power of the input signal (or the output power).

Therefore, as shown in FIG. 2C, when the average power of the input signal decreases, the load impedance is increased from the load line (B) to the load line (C) (that is, the slope of the id-vd characteristic). By reducing the ratio, the ratio of the rising region of the voltage (vd) -current (id) occupied by the load line (C) is reduced to improve the linearity. That is, the distortion characteristics can be improved and the efficiency can be improved by performing both the power supply voltage control and the load impedance control. Note that the gain change at this time is compensated by the VGA of the driver stage.
JP 2000-174559 A

  However, in the conventional power amplifying device described in Patent Document 1 above, when the modulation method changes, the peak power to average power ratio (PAPR) of the input signal changes and the amplitude of the output voltage exceeds that assumed. Therefore, problems such as deterioration of distortion characteristics occur. For example, even in communication using the same frequency band in a multi-mode terminal, the PAPR varies depending on the type of communication mode, such as WCDMA, HSDPA, 3.9G. Therefore, if the load impedance control is performed only with the average power of the input signal as in the conventional power amplifying device, the distortion characteristic may be deteriorated when the modulation method is changed. In particular, the distortion characteristics are significantly deteriorated with modulated signals having different PAPRs. Furthermore, since the back-off is required, the transmitter efficiency may be deteriorated.

  An object of the present invention is to provide a high-efficiency and low-distortion power amplifying apparatus that can be applied to a multimode terminal that supports various modulation schemes, and a radio transmission apparatus using the power amplifying apparatus. .

  The power amplifying apparatus of the present invention is a power amplifying apparatus for amplifying the power of the RF signal, and a variable gain amplifier for variably amplifying the power of the RF signal, and amplifies the RF signal based on the magnitude of the power supply voltage. A transistor, an impedance matching circuit for adjusting a load impedance of the RF signal, and the power supply voltage control so that a saturation voltage and the peak power of the transistor are equal based on a peak power of the RF signal, and the RF signal The load impedance of the impedance matching circuit is controlled based on the peak power of the transistor so that the transistor can output the maximum power, and the total gain is constant based on the average power of the RF signal. And a control means for controlling the gain of the variable gain amplifier.

  According to the present invention, the power supply voltage and load impedance of the transistor are changed based on the peak power and average power of the RF signal corresponding to the modulation mode. This allows the transistor to perform power amplification in an optimum state corresponding to each modulation mode. Therefore, even in a multi-mode portable terminal in which the modulation mode system is variously changed, power amplification of the RF signal can be performed with high efficiency and low distortion. As a result, a wireless signal with high efficiency and low distortion can be transmitted from the wireless transmission device.

Configuration diagram showing an example of a conventional power amplifier Characteristic diagram showing voltage-current characteristics and load characteristics of transistor amplifier FIG. 6 is a characteristic diagram showing voltage-current characteristics and load characteristics of an amplifying transistor applied to the power amplifying device of the present invention. FIG. 6 is a characteristic diagram showing voltage-current characteristics and load characteristics of an amplifying transistor when the modulation mode changes and the peak power of the input signal changes in the power amplification device of the present invention The block diagram which shows the structure of the power amplification apparatus which concerns on Embodiment 1 of this invention. The circuit diagram which shows an example of the load impedance variable circuit with which the output matching circuit of the power amplification apparatus shown in FIG. FIG. 6 is a characteristic diagram showing the operation of the load impedance variable circuit shown in FIG. The block diagram which shows the structure of the power amplifier which concerns on Embodiment 2 of this invention. The block diagram which shows the structure of the power amplification apparatus which concerns on Embodiment 3 of this invention. The block diagram which shows the structure of the power amplification apparatus which concerns on Embodiment 4 of this invention. Block diagram showing the configuration of a wireless transmission apparatus according to Embodiment 5 of the present invention The block diagram which shows the structure of the radio | wireless transmitter which concerns on Embodiment 6 of this invention.

<Summary of invention>
In the power amplifying device of the present invention, not only the average power of the RF signal input to the power amplifying device but also the peak power of the RF signal is used to control the power supply voltage and load impedance of the transistor. As a result, it is compensated that the power is amplified without generating distortion in the peak power, so that the distortion characteristics do not deteriorate. In addition, the power amplifying device of the present invention compensates for variations in amplification factor due to power supply voltage control and load impedance control based on average power. As a result, even if the amplification factor fluctuates, it is possible to realize transmission power with an accurate power level corresponding to the power supply voltage and the load impedance. Furthermore, the power amplifying apparatus of the present invention uses TPC (transmission power control) information as average power, and uses TPC information + PAPR (peak power to average power ratio) information as peak power. Thus, by holding the PAPR value for each modulation mode in advance, it is possible to perform amplification with low distortion and high efficiency even in a multimode terminal.

  Here, the concept of power supply voltage control and load impedance control in an amplifying transistor applied to the power amplifying device of the present invention will be described. FIG. 3 is a characteristic diagram showing voltage-current characteristics and load characteristics of an amplifying transistor applied to the power amplifying device of the present invention, where the horizontal axis represents the drain voltage (vd) and the vertical axis represents the drain current (id). ).

  In FIG. 3, a load line (A) shows a current swing when the power is large, and a load line (B) shows a current swing when the power is small. A rising region (C) of voltage (vd) -current (id) indicates a region where the linearity of the amplifying transistor is lost and the distortion characteristic is deteriorated. That is, by adjusting the drain voltage (vd) so that the current swing is just below the saturation of the amplifying transistor in accordance with the magnitude of the power, the power is small even when the load line (A) has a large power. Even when the load line (B) is used, high-efficiency amplification can be performed while maintaining good linearity.

  FIG. 4 is a characteristic diagram showing the voltage-current characteristic and load characteristic of the amplifying transistor when the modulation mode changes and the peak power of the input signal changes in the power amplification device of the present invention, and the horizontal axis indicates the drain voltage. (Vd), and the vertical axis represents the drain current (id). Note that the modulation mode includes a modulation scheme, the number of code multiplexes, a channel configuration, a peak suppression parameter, and the like. As shown in FIG. 4, when the peak power is large, the current swing is increased as in the load line (A) (that is, the slope of the load line is increased), and when the peak power is small, the load line (B). As shown, the current swing is reduced, that is, the slope of the load line is made gentle.

  Thus, if the swing of the current is changed by controlling the magnitude of the load impedance according to the modulation mode, the rising region (C) of voltage (vd) -current (id) is not used. Good linearity can be maintained whether the power is large or small. That is, by changing the load line according to the magnitude of the peak power, it is possible to perform highly efficient power amplification without distorting the input signal even in a multimode terminal.

  That is, the power amplification device of the present invention can efficiently amplify even with low power by controlling the power supply voltage according to the magnitude of power in the basic form. Moreover, by changing the magnitude of the load impedance according to the magnitude of the peak power, it is possible to maintain high efficiency while ensuring good linearity. As a control method at this time, it is only necessary to have one power-to-power voltage correspondence table regardless of the modulation method. In the power amplifying apparatus of the present invention, the load impedance is controlled according to the peak power, but is amplified by the variable gain amplifier on the input side so that the gain of the entire power amplifying apparatus is not changed by changing the load impedance. The rate is fine-tuned.

  Next, some specific embodiments of the power amplifying device according to the present invention will be described in detail. Note that, in the drawings used in the following embodiments, the same components are denoted by the same reference numerals, and redundant description is omitted as much as possible.

<Embodiment 1>
First, the configuration of the power amplifying apparatus according to Embodiment 1 of the present invention will be described. FIG. 5 is a block diagram showing a configuration of the power amplifying apparatus according to Embodiment 1 of the present invention. 5 includes a coupler 101, an envelope detector 102, an average processing unit 103, a peak detection unit 104, a variable gain amplifier 105, an input matching circuit 106, an amplifying transistor 107, and an output. The configuration includes a matching circuit 108 and an amplifier control unit 109.

  The coupler 101 has a function of inputting an RF band signal and extracting a part of the RF signal. The envelope detector 102 has a function of extracting envelope information from the RF modulated wave extracted from the coupler 101. The average processing unit 103 has a function of obtaining the average power of the RF signal from the envelope information extracted by the envelope detector 102. The peak detection unit 104 has a function of detecting peak power in a predetermined time interval from envelope information extracted by the envelope detector 102.

  The variable gain amplifier 105 has a function of changing the power amplification factor of the input RF signal to a desired value in accordance with the fluctuation of the amplification factor of the transistor 107. The input matching circuit 106 has a function of matching the impedance on the input side of the power amplifier. The amplifying transistor 107 has a function of changing the saturation power in accordance with the magnitude of the power supply voltage input from the amplifier control unit 109. The output matching circuit 108 includes an impedance variable circuit (not shown), and has a function of changing the load impedance based on a control signal from the amplifier control unit 109. The amplifier control unit 109 receives the average power obtained by the average processing unit 103 and the peak power obtained by the peak detection unit 104, and inputs the amplification factor of the variable gain amplifier 105, the power supply voltage of the transistor 107, and the load impedance. It has a function to change.

  In such a configuration, the power amplifying apparatus shown in FIG. 5 changes the power supply voltage and the load impedance of the transistor 107 based on the peak power obtained by the peak detection unit 104 and the average power obtained by the average processing unit 103. Further, based on the average power obtained by the average processing unit 103, the gain of the variable gain amplifier 105 is adjusted in accordance with the variation of the amplification factor of the transistor 107 so that the total gain as the power amplification device becomes constant. be able to.

  Next, the operation of the power amplifying apparatus according to Embodiment 1 shown in FIG. 5 will be described. In the RF input line, a coupler 101 is provided at the input stage of a power amplifying apparatus including a variable gain amplifier 105, an input matching circuit 106, a transistor 107, and an output matching circuit 108, and an input RF signal (hereinafter referred to as an input signal) is supplied. A part is taken out by the coupler 101. The input signal extracted by the coupler 101 is extracted as envelope information of the RF modulated wave by the envelope detector 102 and input to the average processing unit 103 and the peak detection unit 104.

  The average processing unit 103 outputs average power from the extracted envelope information, and the peak detection unit 104 detects peak power within a predetermined time interval. Both the average processing unit 103 and the peak detection unit 104 may perform analog processing or digital processing. When digital processing is performed, the output of the analog envelope detector 102 may be converted into a digital signal by an A / D converter or the like as necessary. In addition, it is desirable that the length of the predetermined time section is the maximum time during which the average power does not vary. For example, it is desirable to use the transmission power control (TPC) control period, the time of one frame of the wireless transmission signal, or the like.

  Both the average power output from the average processing unit 103 and the maximum power (peak power) output from the peak detection unit 104 are input to the amplifier control unit 109. Then, the amplifier control unit 109 adjusts the amplification factor of the variable gain amplifier 105 and the power supply voltage of the transistor 107 based on the input average power and peak power, and at least the input matching circuit 106 and the output matching circuit 108. Adjust one impedance. Normally, the impedances of both the input matching circuit 106 and the output matching circuit 108 are adjusted.

An adjustment procedure by the amplifier control unit 109 at this time will be described. First, the amplifier control unit 109 calculates a peak power value Pout_peak and an average power value Pout_avg expected as an output of the amplifier of the transistor 107 from the input peak power value Pin_peak and average power value Pin_avg. Here, when the expected average power value Pout_avg of the output is known, the following equation (1) is established.
Pout_peak = Pin_peak + (Pout_ave−Pin_avg) (1)

In addition, when the gain G of the amplifier of the transistor 107 is known, the average power value Pout_avg and the peak power value Pout_peak expected as the output of the transistor 107 are respectively expressed by the following equations (2) and (3 ).
Pout_avg = Pin_avg + G (2)
Pout_peak = Pin_peak + G (3)

  Next, when the peak power value Pout_peak expected as the output of the amplifier of the transistor 107 is equal to the maximum output power of the transistor 107, the power supply voltage is adjusted to be equal to the rated voltage of the transistor 107. The output impedance of the output matching circuit 108 is adjusted so as to satisfy the matching condition that can output the maximum power.

  When the peak power value Pout_peak expected as the output of the amplifier of the transistor 107 is smaller than the maximum output power of the transistor 107, the power supply voltage is set lower than the rated voltage of the transistor 107, and the output impedance of the output matching circuit 108 is increased. To do. That is, by lowering the power supply voltage and increasing the output impedance, the substantial saturation power of the amplifier of the transistor 107 becomes lower than the maximum output power of the transistor 107, and the input peak power value and the amplifier of the transistor 107 are reduced. Can be made equal to the substantial saturation power. In addition, since the amplifier of the transistor 107 operates near saturation power, the transistor 107 can operate with high efficiency. Further, since the peak power becomes equal to the substantial saturation power, no distortion occurs in the peak power, so that the amplifier of the transistor 107 can be reduced in distortion.

  Further, the gain G (= Pout_avg−Pin_avg) of the amplifier of the transistor 107 can be increased by controlling the load impedance. Further, the gain G of the amplifier of the transistor 107 can be changed also by changing the power supply voltage. With these changes (that is, changes in gain G), the amplification factor of the variable gain amplifier 105 is adjusted so that the expected output power can be obtained, and appropriate power is input to the input matching circuit 106 of the transistor 107. In other words, the gain of the variable gain amplifier 105 is adjusted in accordance with the fluctuation of the amplification factor of the transistor 107 so that the total gain as the power amplification device becomes constant.

  FIG. 6 is a circuit diagram showing an example of a load impedance variable circuit included in the output matching circuit 108 of the power amplification device shown in FIG. FIG. 7 is a characteristic diagram showing the operation of the load impedance variable circuit shown in FIG. In FIG. 7, the horizontal axis represents the load impedance adjustment terminal voltage Vz (V) shown in FIG. 6, and the vertical axis represents the load impedance Z (Ω) viewed from the input side of the load impedance variable circuit shown in FIG.

  The load impedance variable circuit shown in FIG. 6 has a configuration in which a T-type LC circuit and an isolator 110 are connected in series, and a variable capacitor C110 is formed by a parallel capacitor and a varactor diode. By changing the load impedance adjustment terminal voltage Vz of the variable capacitance capacitor C110 of FIG. 6 according to the control voltage of the amplifier control unit 109 of FIG. 5, it is possible to change the load impedance by changing the capacitance of the variable capacitance capacitor C110. . That is, by controlling the load impedance adjustment terminal voltage Vz of the capacitance variable capacitor C110 of FIG. 6, for example, the load impedance Z can be arbitrarily changed within a range of 50Ω to 150Ω as shown in FIG.

  That is, in the power amplifying apparatus shown in FIG. 5, the power supply voltage of the transistor 107 and the load impedance are controlled by the peak power in a predetermined section of the envelope in the input RF signal. Further, variation in the amplification factor of the transistor 107 is compensated by average power and peak power. At this time, the average power and peak power calculation sections are held for a certain period of time (for example, a burst section).

<Embodiment 2>
FIG. 8 is a block diagram showing the configuration of the power amplifying apparatus according to Embodiment 2 of the present invention. The power amplifying device of the second embodiment shown in FIG. 8 is obtained by removing the coupler 101, the envelope detector 102, the average processing unit 103, and the peak detecting unit 104 from the power amplifying device of the first embodiment shown in FIG. It has a configuration. That is, the power amplifying apparatus according to the second embodiment shown in FIG. 8 includes a variable gain amplifier 105, an input matching circuit 106, a transistor 107, an output matching circuit 108, and an amplifier control unit 109a.

  In such a configuration, the amplifier control unit 109a receives a TPC signal and a PAPR signal as input signal information, instead of having information on the average power value and the peak power value. Based on the input TPC signal and PAPR signal, the amplifier control unit 109a calculates the peak power value Pout_peak and the average power value Pout_avg expected as the output of the amplifier of the transistor 107 by the following equations (4) and (5). calculate. Other processes are the same as those in the first embodiment.

Pout_peak = TPC value + PAPR value (4)
Pout_avg = TPC value (5)

  That is, information on the average power value Pout_avg expected as the output of the amplifier of the transistor 107 is calculated from the TPC signal (ie, TPC command), and information on the peak power value Pout_peak expected as the output of the amplifier of the transistor 107 is Calculation is performed based on the TPC signal and the PAPR signal.

  The PAPR value may be calculated from a PAPR signal extracted from a digital baseband signal, or may be a theoretical maximum power value for each modulation mode stored in advance in a table. In the case of a fixed mode terminal, The PAPR information may be held in a ROM or the like inside the amplifier control unit 109a.

  In this manner, when the amplifier control unit 109a inputs the TPC signal and the PAPR signal, the average power and the peak power can be obtained without complicating the configuration of the analog unit. Then, based on the average power and the peak power, the power supply voltage and load impedance of the transistor 107 are changed, and further, in accordance with the variation of the amplification factor of the transistor 107 so that the total gain as the power amplification device becomes constant. The gain of the variable gain amplifier can be adjusted. This makes it possible to achieve low distortion and highly efficient amplification even in a multimode terminal.

<Embodiment 3>
FIG. 9 is a block diagram showing a configuration of a power amplifying apparatus according to Embodiment 3 of the present invention. The power amplifying device according to the third embodiment shown in FIG. 9 has a configuration in which the peak detection unit 104 is removed from the power amplifying device according to the first embodiment shown in FIG. That is, the power amplifying device of the third embodiment shown in FIG. 9 includes a coupler 101, an envelope detector 102, an average processing unit 103, a variable gain amplifier 105, an input matching circuit 106, a transistor 107, an output matching circuit 108, and an amplifier. The control unit 109b is provided.

  That is, since the power amplifying apparatus of the third embodiment does not have a peak detection unit, information on peak power is not input to the amplifier control unit 109b. Therefore, an external PAPR signal and average power information from the average processing unit 103 are input to the amplifier control unit 109b.

The amplifier control unit 109b obtains the peak power value Pout_peak and the average power value Pout_avg expected as the output of the amplifier of the transistor 107 from the average power Pin_avg input from the average processing unit 103 and the PAPR signal input from the outside, as follows: It calculates by Formula (6) and Formula (7). Other processes are the same as those in the first embodiment.
Pout_avg = Pin_avg + G (6)
Pout_peak = Pin_avg + G + PAPR value (7)

  In the power amplifying apparatus of the third embodiment, the average power information is calculated from a value obtained by averaging the output of the envelope detector 102 by the average processing unit 103, and the peak power information is obtained from the baseband signal. It is calculated from the information of the PAPR signal and the average power value.

  The PAPR value may be calculated from a PAPR signal extracted from a digital baseband signal, or may be a theoretical maximum power value for each modulation mode stored in advance in a table. In the case of a fixed mode terminal, The PAPR information may be held in a ROM or the like inside the amplifier control unit 109b.

  In the power amplifying apparatus according to the third embodiment, since the actually observed average power is used, load impedance control can be performed with higher accuracy. Therefore, low-distortion and high-efficiency power amplification can be performed even in a multimode terminal. Can be performed.

<Embodiment 4>
FIG. 10 is a block diagram showing a configuration of a power amplifying apparatus according to Embodiment 4 of the present invention. The power amplifying apparatus of the fourth embodiment shown in FIG. 10 is different from the power amplifying apparatus of the first embodiment shown in FIG. 5 in that the PAPR calculation is performed instead of the presence of the average processing unit 103 and the peak detecting unit 104. A point 112 is provided and a TPC signal is input to the amplifier control unit 109c. That is, the power amplifying device of the fourth embodiment shown in FIG. 10 includes a coupler 101, an envelope detector 102, a PAPR calculator 112, a variable gain amplifier 105, an input matching circuit 106, a transistor 107, an output matching circuit 108, and an amplifier. The control unit 109c is provided.

  That is, the coupler 101 is provided on the RF input side, a part of the input RF signal is taken out, and the envelope detector 102 detects the envelope of the RF signal. Then, the PAPR calculation unit 112 obtains PAPR (peak power to average power ratio) from the result information obtained by detecting the envelope. The PAPR obtained by the PAPR calculation unit 112 is used as PAPR information for the amplifier control unit 109c. On the other hand, a TPC signal is extracted from the outside (baseband unit) and input to the amplifier control unit 109c. Other processes are the same as those in the second embodiment.

  According to the power amplifying apparatus of the fourth embodiment, since the actually observed PAPR is used, the power supply voltage and the load impedance of the transistor 107 can be more accurately detected without being affected by the difference between the digital and analog PAPR. Can be controlled. Even if the input side baseband unit (not shown) is in multimode, low distortion and high efficiency amplification can be performed even in multimode without changing the configuration of the analog unit. .

<Embodiment 5>
In the fifth embodiment, a radio transmission apparatus provided with the power amplification apparatus of the second embodiment will be described. FIG. 11 is a block diagram showing a configuration of a radio transmission apparatus according to Embodiment 5 of the present invention. This wireless transmission device includes a modulation unit 121, a modulation mode control unit 122, a D / A conversion unit 123, a frequency conversion unit 124, in addition to the amplifier unit 113 that constitutes the power amplification device of the second embodiment illustrated in FIG. The configuration includes a PAPR measurement unit 125, a PAPR delay unit 126, a transmission power control unit 127, and a TPC delay unit 128. That is, the wireless transmission device in FIG. 11 shows the overall configuration including the baseband unit of the multimode terminal and the power amplification device.

  The modulation unit 121 has a function of generating a digital baseband signal (modulation signal) from transmission data. The modulation mode control unit 122 has a function of instructing the modulation unit 121 to switch to a desired modulation mode. For example, the modulation mode control unit 122 can instruct switching to a modulation scheme, the number of code multiplexes, a channel configuration, a peak suppression parameter, and the like. The D / A conversion unit 123 has a function of converting the digital baseband signal generated by the modulation unit 121 into an analog baseband signal. The frequency conversion unit 124 has a function of converting an analog baseband signal into an RF band signal.

  The PAPR measurement unit 125 has a function of measuring a PAPR value that is a ratio between the average power and peak power of the digital baseband signal and inputting the measured value to the PAPR delay unit 126. The PAPR delay unit 126 receives the PAPR signal input from the PAPR measurement unit 125 to the amplifier control unit 109a of the amplifier unit 113, and the variable gain amplifier 105 of the amplifier unit 113 from the D / A conversion unit 123 via the frequency conversion unit 124. Has a function of adjusting the delay time difference from the RF signal input to. The transmission power control unit 127 has a function of generating a TPC signal including average power information of the RF signal and inputting the TPC signal to the TPC delay unit 128. The TPC delay unit 128 receives the TPC signal input from the transmission power control unit 127 to the amplifier control unit 109a of the amplifier unit 113, and the variable gain amplifier 105 of the amplifier unit 113 from the D / A conversion unit 123 via the frequency conversion unit 124. Has a function of adjusting the delay time difference from the RF signal input to.

  Next, the operation of the radio transmission apparatus according to Embodiment 5 shown in FIG. 11 will be described. When transmission data is received by the modulation unit 121, the transmission data is modulated into a desired mode by the modulation unit 121 based on an instruction from the modulation mode control unit 122, and output as a digital baseband signal from the modulation unit 121. Is done. The digital baseband signal output from the modulation unit 121 is distributed and input to the PAPR measurement unit 125 and the D / A conversion unit 123.

  The digital baseband signal input to the PAPR measurement unit 125 is measured by the PAPR measurement unit 125 for a PAPR value that is a ratio of average power to peak power. Then, the PAPR signal corresponding to the PAPR value is input to the PAPR delay unit 126, the delay time difference from the RF signal input to the variable gain amplifier 105 of the amplifier unit 113 is adjusted, and input to the amplifier control unit 109a.

  On the other hand, the digital baseband signal input to the D / A converter 123 is converted into an analog baseband signal. Further, the analog baseband signal is converted into an RF signal by the frequency converter 124, and the amplifier 113. To the variable gain amplifier 105. Further, the TPC signal output from the transmission power control unit 127 is input to the TPC delay unit 128, and the delay time difference from the RF signal input to the variable gain amplifier 105 of the amplifier unit 113 is adjusted, and the amplifier control unit 109a is adjusted. Entered.

  In this way, the PAPR signal and the TPC signal are modulated by the PAPR delay unit 126 and the TPC delay unit 128 in the digital unit and the analog unit including the modulation unit 121, the D / A conversion unit 123, and the frequency conversion unit 124. The signal is delayed by the received delay time and input to the amplifier controller 109a at a timing synchronized with the modulation signal. Further, the RF output that is the output of the amplifier unit 113 is transmitted as a radio signal to an antenna (not shown). Note that the operation of the amplifier unit 113 that receives the RF signal, the PAPR signal, and the TPC signal from the multi-mode terminal is the same as the operation described in the second embodiment, and thus a duplicate description is omitted.

  With such a configuration, the operation of the modulation unit 121 is changed to a desired mode by switching between WCDMA and HSDPA by the modulation mode control unit 122. At this time, even if the PAPR of the modulation signal changes, each time the PAPR measurement unit 125 measures the PAPR of the modulation signal and transmits the PAPR signal to the amplifier control unit 109a together with the TPC signal from the transmission power control unit 127. Even if the modulation mode changes, it is possible to transmit a radio signal with high efficiency without deteriorating distortion characteristics.

<Embodiment 6>
FIG. 12 is a block diagram showing a configuration of a radio transmission apparatus according to Embodiment 6 of the present invention. The wireless transmission device of the sixth embodiment shown in FIG. 12 is different from the wireless transmission device of the fifth embodiment shown in FIG. 11 in that a PAPR table that stores PAPR values for each modulation mode instead of having the PAPR measurement unit 125. 129 is provided. That is, the mode signal output from the modulation mode control unit 122 is input to the PAPR table 129, and the PAPR value for each modulation mode stored in advance is selected from the PAPR table 129 corresponding to the mode signal. The PAPR signal corresponding to the selected PAPR value is input to the amplifier control unit 109 after delay adjustment by the PAPR delay unit 126a. Subsequent operations are the same as the operations described in the second embodiment, and a duplicate description is omitted.

  That is, in the wireless transmission device of the sixth embodiment, the PAPR value is not directly measured, but the PAPR value is obtained by referring to the PAPR table 129 based on the mode information transmitted by the modulation mode control unit 122. Then, the PAPR signal corresponding to the PAPR value is input to the amplifier control unit 109a of the amplifier unit 113 together with the TPC signal. As a result, even if the modulation mode changes, it is possible to transmit a radio signal with high efficiency without deteriorating distortion characteristics. The operations after the amplifier unit 113 are the same as those in the fifth embodiment.

<Summary>
That is, the power amplifying device of the present invention performs load impedance control and power supply voltage control of the transistor 107 using average power and peak power. At this time, the average power is used to compensate for fluctuations in the gain of the transistor 107, and the peak power is used to optimize the magnitude of the output voltage swing of the transistor 107.

  As information used for controlling the power supply voltage and load impedance of the transistor 107, the envelope detector 102 detects the instantaneous power of the RF signal, and the average processing unit 103 and the peak detection unit 104 detect the average power and the peak power. Information extracted separately for power is used. Instead of using the envelope detector 102, the average power and the peak power may be obtained directly from the RF signal using the average power sensor and the peak power sensor. Further, the TPC information and the PAPR information may be acquired by performing PAPR detection at the analog stage, or may be acquired by performing PAPR detection at the digital stage. Further, instead of directly detecting PAPR information, a PAPR table may be provided for each modulation mode, and PAPR information corresponding to the modulation mode may be acquired from the PAPR table.

  As a control method for the power amplifying device, a control method for determining the magnitude of the load impedance corresponding to the magnitude of the peak power, and a method for controlling the increase / decrease in the load impedance from the difference in PAPR from the basic mode, There is.

  According to the power amplifying device and the wireless transmission device of the present invention, high efficiency and low distortion can be realized by performing power supply voltage control and load impedance control corresponding to the modulation mode. It can be used effectively for terminals and the like.

  The present invention relates to a power amplifying apparatus that is applied to a mobile communication terminal or the like and amplifies an RF (Radio Frequency) signal.

  Conventionally, in amplifiers used in mobile communication terminals that perform transmission power control, a method of performing power supply voltage control and load impedance control of an amplifier together as a method of realizing high efficiency with low distortion and a wide dynamic range. (For example, refer to Patent Document 1). FIG. 1 is a block diagram showing an example of a conventional power amplifier. As shown in FIG. 1, this power amplifying apparatus mainly includes an input power sensor 1, a coupler 2, a variable gain amplifier 3, an input matching circuit 4, a transistor 5, an output matching circuit 6, and a power supply circuit 7. It has become.

  In this power amplification device, when the input power sensor 1 detects the average power of an RF (Radio Frequency) band input signal supplied to the variable gain amplifier 3 and determines that the average power is small, the power supply circuit 7 The DC voltage supplied to the transistor 5 is lowered, and at the same time, the load impedance control signal is transmitted from the power supply circuit 7 to the output matching circuit 6 so as to increase the load impedance, thereby performing impedance control. In this way, the amplitude of the output voltage can be increased by increasing the load impedance, and as a result, the distortion characteristics can be improved.

  On the other hand, when the input power sensor 1 determines that the average power of the input signal supplied to the variable gain amplifier 3 is large, the DC voltage supplied from the power supply circuit 7 to the transistor 5 is increased and the load impedance is decreased. As a result, the amplitude of the output voltage can be made smaller than the breakdown voltage of the transistor 5 even at high power, and it is possible to perform highly efficient power amplification with less distortion while improving reliability. .

  Here, the reason why low distortion and high efficiency can be realized by performing power supply voltage control and load impedance control of the transistor amplifier together will be described. FIG. 2 is a characteristic diagram showing voltage-current characteristics and load characteristics of a transistor amplifier. FIG. 2A shows the case where power supply voltage control is performed when the average power of the input signal is large, and FIG. 2B shows the average of the input signal. When the power supply voltage control is performed when the power is low, (c) shows the respective characteristics when the power supply voltage control and the load impedance control are performed when the average power of the input signal is small. In each characteristic diagram, the horizontal axis represents the drain voltage (vd) of the transistor amplifier, and the vertical axis represents the drain current (id).

  As shown in FIG. 2A, when the power supply voltage control is performed when the average power of the input signal is large, a good linearity is obtained for the amplification characteristic as in the load line (A). However, when the power supply voltage control is performed when the average power of the input signal is small, load characteristics such as the load line (B) shown in FIG. 2B are obtained, so that voltage (vd) -current (id) The linearity is lost in the rising region, and the distortion characteristics deteriorate. That is, the linearity is deteriorated simply by controlling the power supply voltage according to the average power of the input signal (or the output power).

Therefore, as shown in FIG. 2C, when the average power of the input signal decreases, the load impedance is increased from the load line (B) to the load line (C) (that is, the slope of the id-vd characteristic). By reducing the ratio, the ratio of the rising area of the voltage (vd) -current (id) occupied by the load line (C) is reduced to improve the linearity. In other words, improvement of distortion characteristics and high efficiency can be realized by performing power supply voltage control and load impedance control together. Note that the gain change at this time is compensated by the VGA of the driver stage.
JP 2000-174559 A

  However, in the conventional power amplifying device described in Patent Document 1 above, when the modulation method changes, the peak power to average power ratio (PAPR) of the input signal changes and the amplitude of the output voltage exceeds that assumed. Therefore, problems such as deterioration of distortion characteristics occur. For example, even in communication using the same frequency band in a multi-mode terminal, the PAPR varies depending on the type of communication mode, such as WCDMA, HSDPA, 3.9G. Therefore, if the load impedance control is performed only with the average power of the input signal as in the conventional power amplifying device, the distortion characteristic may be deteriorated when the modulation method is changed. In particular, the distortion characteristics are significantly deteriorated with modulated signals having different PAPRs. Furthermore, since the back-off is required, the transmitter efficiency may be deteriorated.

  An object of the present invention is to provide a high-efficiency and low-distortion power amplifying apparatus that can be applied to a multimode terminal that supports various modulation schemes, and a radio transmission apparatus using the power amplifying apparatus. .

  A power amplifying apparatus according to the present invention is a power amplifying apparatus for amplifying the power of an RF signal, and a variable gain amplifier that variably amplifies the power of the RF signal, and amplifies the RF signal based on the magnitude of a power supply voltage. A transistor, an impedance matching circuit for adjusting a load impedance of the RF signal, and the power supply voltage control so that a saturation voltage and the peak power of the transistor are equal based on a peak power of the RF signal, and the RF signal The load impedance of the impedance matching circuit is controlled based on the peak power of the transistor so that the transistor can output the maximum power, and the total gain is constant based on the average power of the RF signal. And a control means for controlling the gain of the variable gain amplifier.

  According to the present invention, the power supply voltage and load impedance of the transistor are changed based on the peak power and average power of the RF signal corresponding to the modulation mode. This allows the transistor to perform power amplification in an optimum state corresponding to each modulation mode. Therefore, even in a multi-mode portable terminal in which the modulation mode system is variously changed, power amplification of the RF signal can be performed with high efficiency and low distortion. As a result, a wireless signal with high efficiency and low distortion can be transmitted from the wireless transmission device.

<Summary of invention>
In the power amplifying device of the present invention, not only the average power of the RF signal input to the power amplifying device but also the peak power of the RF signal is used to control the power supply voltage and load impedance of the transistor. As a result, it is compensated that the power is amplified without generating distortion in the peak power, so that the distortion characteristics do not deteriorate. In addition, the power amplifying device of the present invention compensates for variations in amplification factor due to power supply voltage control and load impedance control based on average power. As a result, even if the amplification factor fluctuates, it is possible to realize transmission power with an accurate power level corresponding to the power supply voltage and the load impedance. Furthermore, the power amplifying apparatus of the present invention uses TPC (transmission power control) information as average power, and uses TPC information + PAPR (peak power to average power ratio) information as peak power. Thus, by holding the PAPR value for each modulation mode in advance, it is possible to perform amplification with low distortion and high efficiency even in a multimode terminal.

  Here, the concept of power supply voltage control and load impedance control in an amplifying transistor applied to the power amplifying device of the present invention will be described. FIG. 3 is a characteristic diagram showing voltage-current characteristics and load characteristics of an amplifying transistor applied to the power amplifying device of the present invention, where the horizontal axis represents the drain voltage (vd) and the vertical axis represents the drain current (id). ).

  In FIG. 3, a load line (A) shows a current swing when the power is large, and a load line (B) shows a current swing when the power is small. A rising region (C) of voltage (vd) -current (id) indicates a region where the linearity of the amplifying transistor is lost and the distortion characteristic is deteriorated. That is, by adjusting the drain voltage (vd) so that the current swing is just below the saturation of the amplifying transistor in accordance with the magnitude of the power, the power is small even when the load line (A) has a large power. Even when the load line (B) is used, high-efficiency amplification can be performed while maintaining good linearity.

  FIG. 4 is a characteristic diagram showing the voltage-current characteristic and load characteristic of the amplifying transistor when the modulation mode changes and the peak power of the input signal changes in the power amplification device of the present invention, and the horizontal axis indicates the drain voltage. (Vd), and the vertical axis represents the drain current (id). Note that the modulation mode includes a modulation scheme, the number of code multiplexes, a channel configuration, a peak suppression parameter, and the like. As shown in FIG. 4, when the peak power is large, the current swing is increased as in the load line (A) (that is, the slope of the load line is increased), and when the peak power is small, the load line (B). As shown, the current swing is reduced, that is, the slope of the load line is made gentle.

  Thus, if the swing of the current is changed by controlling the magnitude of the load impedance according to the modulation mode, the rising region (C) of voltage (vd) -current (id) is not used. Good linearity can be maintained whether the power is large or small. That is, by changing the load line according to the magnitude of the peak power, it is possible to perform highly efficient power amplification without distorting the input signal even in a multimode terminal.

That is, the power amplification device of the present invention can efficiently amplify even with low power by controlling the power supply voltage according to the magnitude of power in the basic form. Moreover, by changing the magnitude of the load impedance according to the magnitude of the peak power, it is possible to maintain high efficiency while ensuring good linearity. As a control method at this time, it is only necessary to have one power-to-power voltage correspondence table regardless of the modulation method. In the power amplifying apparatus of the present invention, the load impedance is controlled according to the peak power, but is amplified by the variable gain amplifier on the input side so that the gain of the entire power amplifying apparatus is not changed by changing the load impedance. The rate is fine-tuned.

  Next, some specific embodiments of the power amplifying device according to the present invention will be described in detail. Note that, in the drawings used in the following embodiments, the same components are denoted by the same reference numerals, and redundant description is omitted as much as possible.

<Embodiment 1>
First, the configuration of the power amplifying apparatus according to Embodiment 1 of the present invention will be described. FIG. 5 is a block diagram showing a configuration of the power amplifying apparatus according to Embodiment 1 of the present invention. 5 includes a coupler 101, an envelope detector 102, an average processing unit 103, a peak detection unit 104, a variable gain amplifier 105, an input matching circuit 106, an amplifying transistor 107, and an output. The configuration includes a matching circuit 108 and an amplifier control unit 109.

  The coupler 101 has a function of inputting an RF band signal and extracting a part of the RF signal. The envelope detector 102 has a function of extracting envelope information from the RF modulated wave extracted from the coupler 101. The average processing unit 103 has a function of obtaining the average power of the RF signal from the envelope information extracted by the envelope detector 102. The peak detection unit 104 has a function of detecting peak power in a predetermined time interval from envelope information extracted by the envelope detector 102.

  The variable gain amplifier 105 has a function of changing the power amplification factor of the input RF signal to a desired value in accordance with the fluctuation of the amplification factor of the transistor 107. The input matching circuit 106 has a function of matching the impedance on the input side of the power amplifier. The amplifying transistor 107 has a function of changing the saturation power in accordance with the magnitude of the power supply voltage input from the amplifier control unit 109. The output matching circuit 108 includes an impedance variable circuit (not shown), and has a function of changing the load impedance based on a control signal from the amplifier control unit 109. The amplifier control unit 109 receives the average power obtained by the average processing unit 103 and the peak power obtained by the peak detection unit 104, and inputs the amplification factor of the variable gain amplifier 105, the power supply voltage of the transistor 107, and the load impedance. It has a function to change.

  In such a configuration, the power amplifying apparatus shown in FIG. 5 changes the power supply voltage and the load impedance of the transistor 107 based on the peak power obtained by the peak detection unit 104 and the average power obtained by the average processing unit 103. Further, based on the average power obtained by the average processing unit 103, the gain of the variable gain amplifier 105 is adjusted in accordance with the variation of the amplification factor of the transistor 107 so that the total gain as the power amplification device becomes constant. be able to.

  Next, the operation of the power amplifying apparatus according to Embodiment 1 shown in FIG. 5 will be described. In the RF input line, a coupler 101 is provided at the input stage of a power amplifying apparatus including a variable gain amplifier 105, an input matching circuit 106, a transistor 107, and an output matching circuit 108, and an input RF signal (hereinafter referred to as an input signal) is supplied. A part is taken out by the coupler 101. The input signal extracted by the coupler 101 is extracted as envelope information of the RF modulated wave by the envelope detector 102 and input to the average processing unit 103 and the peak detection unit 104.

The average processing unit 103 outputs average power from the extracted envelope information, and the peak detection unit 104 detects peak power within a predetermined time interval. Both the average processing unit 103 and the peak detection unit 104 may perform analog processing or digital processing. When digital processing is performed, the output of the analog envelope detector 102 may be converted into a digital signal by an A / D converter or the like as necessary. In addition, the length of the predetermined time interval is preferably the maximum time during which the average power does not vary. For example, it is desirable to use a transmission power control (TPC) control period, the time of one frame of a radio transmission signal, or the like.

  Both the average power output from the average processing unit 103 and the maximum power (peak power) output from the peak detection unit 104 are input to the amplifier control unit 109. Then, the amplifier control unit 109 adjusts the amplification factor of the variable gain amplifier 105 and the power supply voltage of the transistor 107 based on the input average power and peak power, and at least the input matching circuit 106 and the output matching circuit 108. Adjust one impedance. Normally, the impedances of both the input matching circuit 106 and the output matching circuit 108 are adjusted.

An adjustment procedure by the amplifier control unit 109 at this time will be described. First, the amplifier control unit 109 calculates a peak power value Pout_peak and an average power value Pout_avg expected as an output of the amplifier of the transistor 107 from the input peak power value Pin_peak and average power value Pin_avg. Here, when the expected average power value Pout_avg of the output is known, the following equation (1) is established.
Pout_peak = Pin_peak + (Pout_ave−Pin_avg) (1)

When the gain G of the amplifier of the transistor 107 is known, the average power value Pout_avg and the peak power value Pout_peak expected as the output of the transistor 107 are respectively expressed by the following equations (2) and (3 ).
Pout_avg = Pin_avg + G (2)
Pout_peak = Pin_peak + G (3)

  Next, when the peak power value Pout_peak expected as the output of the amplifier of the transistor 107 is equal to the maximum output power of the transistor 107, the power supply voltage is adjusted to be equal to the rated voltage of the transistor 107. The output impedance of the output matching circuit 108 is adjusted so as to satisfy the matching condition that can output the maximum power.

  When the peak power value Pout_peak expected as the output of the amplifier of the transistor 107 is smaller than the maximum output power of the transistor 107, the power supply voltage is set lower than the rated voltage of the transistor 107, and the output impedance of the output matching circuit 108 is increased. To do. That is, by lowering the power supply voltage and increasing the output impedance, the substantial saturation power of the amplifier of the transistor 107 becomes lower than the maximum output power of the transistor 107, and the input peak power value and the amplifier of the transistor 107 are reduced. Can be made equal to the substantial saturation power. In addition, since the amplifier of the transistor 107 operates near saturation power, the transistor 107 can operate with high efficiency. Further, since the peak power becomes equal to the substantial saturation power, no distortion occurs in the peak power, so that the amplifier of the transistor 107 can be reduced in distortion.

  Further, the gain G (= Pout_avg−Pin_avg) of the amplifier of the transistor 107 can be increased by controlling the load impedance. Further, the gain G of the amplifier of the transistor 107 can be changed also by changing the power supply voltage. With these changes (that is, changes in gain G), the amplification factor of the variable gain amplifier 105 is adjusted so that the expected output power can be obtained, and appropriate power is input to the input matching circuit 106 of the transistor 107. In other words, the gain of the variable gain amplifier 105 is adjusted in accordance with the fluctuation of the amplification factor of the transistor 107 so that the total gain as the power amplification device becomes constant.

  FIG. 6 is a circuit diagram showing an example of a load impedance variable circuit included in the output matching circuit 108 of the power amplification device shown in FIG. FIG. 7 is a characteristic diagram showing the operation of the load impedance variable circuit shown in FIG. In FIG. 7, the horizontal axis represents the load impedance adjustment terminal voltage Vz (V) shown in FIG. 6, and the vertical axis represents the load impedance Z (Ω) viewed from the input side of the load impedance variable circuit shown in FIG.

  The load impedance variable circuit shown in FIG. 6 has a configuration in which a T-type LC circuit and an isolator 110 are connected in series, and a variable capacitor C110 is formed by a parallel capacitor and a varactor diode. By changing the load impedance adjustment terminal voltage Vz of the variable capacitance capacitor C110 of FIG. 6 according to the control voltage of the amplifier control unit 109 of FIG. 5, it is possible to change the load impedance by changing the capacitance of the variable capacitance capacitor C110. . That is, by controlling the load impedance adjustment terminal voltage Vz of the capacitance variable capacitor C110 of FIG. 6, for example, the load impedance Z can be arbitrarily changed within a range of 50Ω to 150Ω as shown in FIG.

  That is, in the power amplifying apparatus shown in FIG. 5, the power supply voltage of the transistor 107 and the load impedance are controlled by the peak power in a predetermined section of the envelope in the input RF signal. Further, variation in the amplification factor of the transistor 107 is compensated by average power and peak power. At this time, the average power and peak power calculation sections are held for a certain period of time (for example, a burst section).

<Embodiment 2>
FIG. 8 is a block diagram showing a configuration of a power amplifying apparatus according to Embodiment 2 of the present invention. The power amplifying device of the second embodiment shown in FIG. 8 is obtained by removing the coupler 101, the envelope detector 102, the average processing unit 103, and the peak detecting unit 104 from the power amplifying device of the first embodiment shown in FIG. It has a configuration. That is, the power amplifying device of the second embodiment shown in FIG. 8 has a configuration including a variable gain amplifier 105, an input matching circuit 106, a transistor 107, an output matching circuit 108, and an amplifier control unit 109a.

  In such a configuration, the amplifier control unit 109a receives a TPC signal and a PAPR signal as input signal information, instead of having information on the average power value and the peak power value. Based on the input TPC signal and PAPR signal, the amplifier control unit 109a calculates the peak power value Pout_peak and the average power value Pout_avg expected as the output of the amplifier of the transistor 107 by the following equations (4) and (5). calculate. Other processes are the same as those in the first embodiment.

Pout_peak = TPC value + PAPR value (4)
Pout_avg = TPC value (5)

  That is, information on the average power value Pout_avg expected as the output of the amplifier of the transistor 107 is calculated from the TPC signal (ie, TPC command), and information on the peak power value Pout_peak expected as the output of the amplifier of the transistor 107 is Calculation is performed based on the TPC signal and the PAPR signal.

  The PAPR value may be calculated from a PAPR signal extracted from a digital baseband signal, or may be a theoretical maximum power value for each modulation mode stored in advance in a table. In the case of a fixed mode terminal, The PAPR information may be held in a ROM or the like inside the amplifier control unit 109a.

In this manner, when the amplifier control unit 109a inputs the TPC signal and the PAPR signal, the average power and the peak power can be obtained without complicating the configuration of the analog unit. Then, based on the average power and the peak power, the power supply voltage and load impedance of the transistor 107 are changed, and further, in accordance with the variation of the amplification factor of the transistor 107 so that the total gain as the power amplification device becomes constant. The gain of the variable gain amplifier can be adjusted. This makes it possible to achieve low distortion and highly efficient amplification even in a multimode terminal.

<Embodiment 3>
FIG. 9 is a block diagram showing a configuration of a power amplifying apparatus according to Embodiment 3 of the present invention. The power amplifying device according to the third embodiment shown in FIG. 9 has a configuration in which the peak detection unit 104 is removed from the power amplifying device according to the first embodiment shown in FIG. That is, the power amplifying device of the third embodiment shown in FIG. 9 includes a coupler 101, an envelope detector 102, an average processing unit 103, a variable gain amplifier 105, an input matching circuit 106, a transistor 107, an output matching circuit 108, and an amplifier. The control unit 109b is provided.

  That is, since the power amplifying apparatus of the third embodiment does not have a peak detection unit, information on peak power is not input to the amplifier control unit 109b. Therefore, an external PAPR signal and average power information from the average processing unit 103 are input to the amplifier control unit 109b.

The amplifier control unit 109b obtains the peak power value Pout_peak and the average power value Pout_avg expected as the output of the amplifier of the transistor 107 from the average power Pin_avg input from the average processing unit 103 and the PAPR signal input from the outside, as follows: It calculates by Formula (6) and Formula (7). Other processes are the same as those in the first embodiment.
Pout_avg = Pin_avg + G (6)
Pout_peak = Pin_avg + G + PAPR value (7)

  In the power amplifying apparatus of the third embodiment, the average power information is calculated from a value obtained by averaging the output of the envelope detector 102 by the average processing unit 103, and the peak power information is obtained from the baseband signal. It is calculated from the information of the PAPR signal and the average power value.

  The PAPR value may be calculated from a PAPR signal extracted from a digital baseband signal, or may be a theoretical maximum power value for each modulation mode stored in advance in a table. In the case of a fixed mode terminal, The PAPR information may be held in a ROM or the like inside the amplifier control unit 109b.

  In the power amplifying apparatus according to the third embodiment, since the actually observed average power is used, load impedance control can be performed with higher accuracy. Therefore, low-distortion and high-efficiency power amplification can be performed even in a multimode terminal. Can be performed.

<Embodiment 4>
FIG. 10 is a block diagram showing a configuration of a power amplifying apparatus according to Embodiment 4 of the present invention. The power amplifying apparatus of the fourth embodiment shown in FIG. 10 differs from the power amplifying apparatus of the first embodiment shown in FIG. 5 in that the PAPR calculation is performed instead of the presence of the average processing unit 103 and the peak detecting unit 104. A point 112 is provided and a TPC signal is input to the amplifier control unit 109c. That is, the power amplifying apparatus of the fourth embodiment shown in FIG. 10 includes a coupler 101, an envelope detector 102, a PAPR calculator 112, a variable gain amplifier 105, an input matching circuit 106, a transistor 107, an output matching circuit 108, and an amplifier. The control unit 109c is provided.

  That is, the coupler 101 is provided on the RF input side, a part of the input RF signal is taken out, and the envelope detector 102 detects the envelope of the RF signal. Then, the PAPR calculation unit 112 obtains PAPR (peak power to average power ratio) from the result information obtained by detecting the envelope. The PAPR obtained by the PAPR calculation unit 112 is used as PAPR information for the amplifier control unit 109c. On the other hand, a TPC signal is extracted from the outside (baseband unit) and input to the amplifier control unit 109c. Other processes are the same as those in the second embodiment.

  According to the power amplifying apparatus of the fourth embodiment, since the actually observed PAPR is used, the power supply voltage and the load impedance of the transistor 107 can be more accurately detected without being affected by the difference between the digital and analog PAPR. Can be controlled. Even if the input side baseband unit (not shown) is in multimode, low distortion and high efficiency amplification can be performed even in multimode without changing the configuration of the analog unit. .

<Embodiment 5>
In the fifth embodiment, a radio transmission apparatus provided with the power amplification apparatus of the second embodiment will be described. FIG. 11 is a block diagram showing a configuration of a radio transmission apparatus according to Embodiment 5 of the present invention. This wireless transmission device includes a modulation unit 121, a modulation mode control unit 122, a D / A conversion unit 123, a frequency conversion unit 124, in addition to the amplifier unit 113 that constitutes the power amplification device of the second embodiment illustrated in FIG. The configuration includes a PAPR measurement unit 125, a PAPR delay unit 126, a transmission power control unit 127, and a TPC delay unit 128. That is, the wireless transmission device in FIG. 11 shows the overall configuration including the baseband unit of the multimode terminal and the power amplification device.

  The modulation unit 121 has a function of generating a digital baseband signal (modulation signal) from transmission data. The modulation mode control unit 122 has a function of instructing the modulation unit 121 to switch to a desired modulation mode. For example, the modulation mode control unit 122 can instruct switching to a modulation scheme, the number of code multiplexes, a channel configuration, a peak suppression parameter, and the like. The D / A conversion unit 123 has a function of converting the digital baseband signal generated by the modulation unit 121 into an analog baseband signal. The frequency conversion unit 124 has a function of converting an analog baseband signal into an RF band signal.

  The PAPR measurement unit 125 has a function of measuring a PAPR value that is a ratio between the average power and peak power of the digital baseband signal and inputting the measured value to the PAPR delay unit 126. The PAPR delay unit 126 receives the PAPR signal input from the PAPR measurement unit 125 to the amplifier control unit 109a of the amplifier unit 113 and the variable gain amplifier 105 of the amplifier unit 113 from the D / A conversion unit 123 via the frequency conversion unit 124. Has a function of adjusting the delay time difference from the RF signal input to. The transmission power control unit 127 has a function of generating a TPC signal including average power information of the RF signal and inputting the TPC signal to the TPC delay unit 128. The TPC delay unit 128 receives the TPC signal input from the transmission power control unit 127 to the amplifier control unit 109a of the amplifier unit 113 and the variable gain amplifier 105 of the amplifier unit 113 from the D / A conversion unit 123 via the frequency conversion unit 124. Has a function of adjusting the delay time difference from the RF signal input to.

  Next, the operation of the radio transmission apparatus according to Embodiment 5 shown in FIG. 11 will be described. When transmission data is received by the modulation unit 121, the transmission data is modulated into a desired mode by the modulation unit 121 based on an instruction from the modulation mode control unit 122, and output as a digital baseband signal from the modulation unit 121. Is done. The digital baseband signal output from the modulation unit 121 is distributed and input to the PAPR measurement unit 125 and the D / A conversion unit 123.

The digital baseband signal input to the PAPR measurement unit 125 is measured by the PAPR measurement unit 125 for a PAPR value that is a ratio of average power to peak power. Then, the PAPR signal corresponding to the PAPR value is input to the PAPR delay unit 126, the delay time difference from the RF signal input to the variable gain amplifier 105 of the amplifier unit 113 is adjusted, and input to the amplifier control unit 109a.

  On the other hand, the digital baseband signal input to the D / A converter 123 is converted into an analog baseband signal. Further, the analog baseband signal is converted into an RF signal by the frequency converter 124, and the amplifier 113. To the variable gain amplifier 105. Further, the TPC signal output from the transmission power control unit 127 is input to the TPC delay unit 128, and the delay time difference from the RF signal input to the variable gain amplifier 105 of the amplifier unit 113 is adjusted, and the amplifier control unit 109a is adjusted. Entered.

  In this way, the PAPR signal and the TPC signal are modulated by the PAPR delay unit 126 and the TPC delay unit 128 in the digital unit and the analog unit including the modulation unit 121, the D / A conversion unit 123, and the frequency conversion unit 124. The signal is delayed by the received delay time and input to the amplifier controller 109a at a timing synchronized with the modulation signal. Further, the RF output that is the output of the amplifier unit 113 is transmitted as a radio signal to an antenna (not shown). Note that the operation of the amplifier unit 113 that receives the RF signal, the PAPR signal, and the TPC signal from the multi-mode terminal is the same as the operation described in the second embodiment, and thus a duplicate description is omitted.

  With such a configuration, the operation of the modulation unit 121 is changed to a desired mode by switching between WCDMA and HSDPA by the modulation mode control unit 122. At this time, even if the PAPR of the modulation signal changes, each time the PAPR measurement unit 125 measures the PAPR of the modulation signal and transmits the PAPR signal to the amplifier control unit 109a together with the TPC signal from the transmission power control unit 127. Even if the modulation mode changes, it is possible to transmit a radio signal with high efficiency without deteriorating distortion characteristics.

<Embodiment 6>
FIG. 12 is a block diagram showing a configuration of a radio transmission apparatus according to Embodiment 6 of the present invention. The wireless transmission device of the sixth embodiment shown in FIG. 12 is different from the wireless transmission device of the fifth embodiment shown in FIG. 11 in that a PAPR table that stores PAPR values for each modulation mode instead of having the PAPR measurement unit 125. 129 is provided. That is, the mode signal output from the modulation mode control unit 122 is input to the PAPR table 129, and the PAPR value for each modulation mode stored in advance is selected from the PAPR table 129 corresponding to the mode signal. The PAPR signal corresponding to the selected PAPR value is input to the amplifier control unit 109 after delay adjustment by the PAPR delay unit 126a. Subsequent operations are the same as the operations described in the second embodiment, and a duplicate description is omitted.

  That is, in the wireless transmission device of the sixth embodiment, the PAPR value is not directly measured, but the PAPR value is obtained by referring to the PAPR table 129 based on the mode information transmitted by the modulation mode control unit 122. Then, the PAPR signal corresponding to the PAPR value is input to the amplifier control unit 109a of the amplifier unit 113 together with the TPC signal. As a result, even if the modulation mode changes, it is possible to transmit a radio signal with high efficiency without deteriorating distortion characteristics. The operations after the amplifier unit 113 are the same as those in the fifth embodiment.

<Summary>
That is, the power amplifying device of the present invention performs load impedance control and power supply voltage control of the transistor 107 using average power and peak power. At this time, the average power is used to compensate for fluctuations in the gain of the transistor 107, and the peak power is used to optimize the magnitude of the output voltage swing of the transistor 107.

  As information used for controlling the power supply voltage and load impedance of the transistor 107, the envelope detector 102 detects the instantaneous power of the RF signal, and the average processing unit 103 and the peak detection unit 104 detect the average power and the peak power. Information extracted separately for power is used. Instead of using the envelope detector 102, the average power and the peak power may be obtained directly from the RF signal using the average power sensor and the peak power sensor. Further, the TPC information and the PAPR information may be acquired by performing PAPR detection at the analog stage, or may be acquired by performing PAPR detection at the digital stage. Further, instead of directly detecting PAPR information, a PAPR table may be provided for each modulation mode, and PAPR information corresponding to the modulation mode may be acquired from the PAPR table.

  As a control method for the power amplifying device, a control method for determining the magnitude of the load impedance corresponding to the magnitude of the peak power, and a method for controlling the increase / decrease in the load impedance from the difference in PAPR from the basic mode, There is.

  According to the power amplifying device and the wireless transmission device of the present invention, high efficiency and low distortion can be realized by performing power supply voltage control and load impedance control corresponding to the modulation mode. It can be used effectively for terminals and the like.

Configuration diagram showing an example of a conventional power amplifier Characteristic diagram showing voltage-current characteristics and load characteristics of transistor amplifier FIG. 6 is a characteristic diagram showing voltage-current characteristics and load characteristics of an amplifying transistor applied to the power amplifying device of the present invention. FIG. 6 is a characteristic diagram showing voltage-current characteristics and load characteristics of an amplifying transistor when the modulation mode changes and the peak power of the input signal changes in the power amplification device of the present invention The block diagram which shows the structure of the power amplification apparatus which concerns on Embodiment 1 of this invention. The circuit diagram which shows an example of the load impedance variable circuit with which the output matching circuit of the power amplification apparatus shown in FIG. FIG. 6 is a characteristic diagram showing the operation of the load impedance variable circuit shown in FIG. The block diagram which shows the structure of the power amplifier which concerns on Embodiment 2 of this invention. The block diagram which shows the structure of the power amplification apparatus which concerns on Embodiment 3 of this invention. The block diagram which shows the structure of the power amplification apparatus which concerns on Embodiment 4 of this invention. Block diagram showing the configuration of a wireless transmission apparatus according to Embodiment 5 of the present invention The block diagram which shows the structure of the radio | wireless transmitter which concerns on Embodiment 6 of this invention.

Claims (5)

A power amplification device for amplifying the power of an RF signal,
A variable gain amplifier that variably amplifies the power of the RF signal;
A transistor that amplifies the RF signal based on the magnitude of the power supply voltage;
An impedance matching circuit for adjusting a load impedance of the RF signal;
The power supply voltage is controlled so that the saturation voltage of the transistor is equal to the peak power based on the peak power of the RF signal, and the matching condition is such that the transistor can output the maximum power based on the peak power of the RF signal; And a control means for controlling the load impedance of the impedance matching circuit to control the gain of the variable gain amplifier so that the total gain is constant based on the average power of the RF signal. . Average power calculating means for calculating the average power of the RF signal;
The power amplification device according to claim 1, further comprising: a peak power calculation unit that detects a peak power of the RF signal.   The power amplifying apparatus according to claim 1, wherein the control unit obtains a peak power and an average power of the RF signal based on a transmission power value and a peak power to average power ratio. Comprising an average power calculating means for calculating an average power of the RF signal;
The power amplifying apparatus according to claim 1, wherein the control unit obtains a peak power of the RF signal based on the average power and a peak power to average power ratio.   The power amplifying apparatus according to claim 3, further comprising a peak power to average power ratio calculating unit that calculates a peak power to average power ratio of the RF signal.

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