WO2008012898A1

WO2008012898A1 - Power amplifying apparatus

Info

Publication number: WO2008012898A1
Application number: PCT/JP2006/314899
Authority: WO
Inventors: Shinji Ueda
Original assignee: Panasonic Corporation
Priority date: 2006-07-27
Filing date: 2006-07-27
Publication date: 2008-01-31

Abstract

A power amplifying apparatus that is applicable to a mobile terminal, especially, a mobile terminal of multicarrier system and that exhibits a high efficiency and low distortions. In this power amplifying apparatus, a TPC set value set by a transmission power setting part (110) is subjected to a delay adjustment by a delay adjusting part (111) and then inputted to a bias value table (112) that is a bias circuit of a peak amplifier (106). The bias value table (112) stores such a bias value of the peak amplifier (106) that the power amplifying apparatus exhibits the maximum efficiency, while satisfying a desired distortion characteristic on a power condition decided based on the TPC set value set by the transmission power setting part (110). A bias setting part (113), therefore, controls, based on a bias setting signal from the bias value table (112), the bias of the peak amplifier (106) such that the highest amplifying efficiency can be obtained with the desired distortion characteristic. That is, a Doherty-type amplifier gradually changes into a class AB amplifier.

Description

Specification

Power amplifier

Technical field

TECHNICAL FIELD [0001] The present invention relates to a power amplifying apparatus that can be mounted on a multi-carrier portable terminal that transmits and receives multi-carrier signals.

Background art

In recent years, multi-carrier schemes that are resistant to multipath and fading are attracting attention as communication schemes capable of realizing high-speed wireless transmission. In such a multi-carrier scheme, transmission signals superimposed on a plurality of carriers (carrier waves) are added on the time axis, resulting in high peak power in the multi-carrier signal. Thus, a Doherty amplifier is known as a power amplifying apparatus that can amplify even a multicarrier signal having such a high peak power with high efficiency (for example, see Non-Patent Document 1).

FIG. 1 is a schematic configuration diagram of a commonly known Dono / Tee amplifier. As shown in Fig. 1, the Doherty amplifier consists of a splitter 1 that distributes the input RF signal, a carrier amplifier 2, a peak amplifier 3, and a first λ Ζ4 transmission line 4 that performs a phase delay of 90 °. The second λ 4 transmission line 5 and the third λ 4 transmission line 6 are used. In such a configuration, the load impedance of the carrier amplifier 2 is modulated by the output current of the peak amplifier 3 by the action of the phase delay of 90 ° by the first λ Ζ4 transmission line 4 and the second λ Ζ4 transmission line 5. .

[0004] In the Doherty amplifier as described above, in a region where the input power is low, only the carrier amplifier 2 operates in a state where the load impedance is high and operates at a high efficiency, and in a region where the input power is high. Since the load impedance of the carrier amplifier 2 is lowered by the output current of the peak amplifier 3 and the saturation power is raised while maintaining high efficiency, even a signal having high peak power can be amplified with high efficiency. That is, it is possible to perform high-efficiency amplification even in a region where the input power is low even in a region where the input power is high. However, in the Dono and Tee amplifiers described above, the carrier amplifier 2 operates with a high load impedance. However, there is a problem that distortion characteristics deteriorate.

[0005] Therefore, various documents have been disclosed in order to solve such a problem of distortion characteristic degradation (see, for example, Patent Document 1 and Patent Document 2). FIG. 2 is a circuit diagram showing a configuration summarizing the power amplifying device disclosed in Patent Document 1. In FIG. The circuit configuration of the power amplifier shown in Fig. 2 controls the bias of the first bias control network 7 and the peak amplifier 3 to control the bias of the carrier amplifier 2 in addition to the configuration of the Dono and Tee amplifiers in Fig. 1. The second bias control network 8 is configured.

FIG. 3 is a characteristic diagram showing the relationship between output power and efficiency in the power amplifying apparatus shown in FIG. 2, with the horizontal axis representing power and the vertical axis representing efficiency. That is, in the circuit configuration shown in FIG. 2, when the output power of the power amplifying device (that is, the output power of the third λλ4 transmission line 6) is low and the low power mode, the power amplifying device operates as a Doherty amplifier. The second bias control network 8 is controlled so that the power amplifier operates as a balance amplifier (that is, a class amplifier) in the high power mode where the output power of the power amplifier is high. 8 is controlling. In other words, in the low power mode where the output power of the power amplifier is low, the second bias control network 8 controls the peak amplifier 3 to be turned off so that the power amplifier operates as a Doherty amplifier. In the high power mode where the output power of the device is high, the bias of the peak amplifier 3 is controlled by the second bias control network 8 so that the power amplifying device operates as a balance amplifier (class AB amplifier).

That is, as shown in FIG. 3, the second bias control network 8 switches the peak amplifier 3 to OFF and ON according to the magnitude of the output power, which is the low power mode or the high power mode. By controlling, the characteristics as a Doherty amplifier and the characteristics as a class AB amplifier are switched. Thus, when the distortion characteristic of the Doherty amplifier exceeds the threshold value (target value) in the region where the peak amplifier 3 is OFF (that is, the region in the low power mode), the second bias control network 8 is connected to the peak amplifier 3. Is turned on (that is, in the high power mode region), increasing the noise and operating as a balance amplifier (Class AB amplifier).

Therefore, in the power amplifying device shown in FIG. 2 described in Patent Document 1, as shown in FIG. 3, the Dono and Tee amplifier characteristics (a) in the region of low output power and low power mode are shown in FIG. As high as In the high power mode region where the output power is high, the efficiency is reduced, but the distortion characteristics are low distortion as in the balanced amplifier characteristics (Class AB amplifier characteristics) (b). In other words, since the power amplifying device shown in FIG. 2 functions as a balance amplifier (class AB amplifier) in the high power mode region, high-efficiency characteristics cannot be obtained in order to prioritize distortion characteristics. Although the distortion is low in the high power mode region, the efficiency is lower than that of the Doherty amplifier characteristics (a).

[0009] Further, a power amplifying apparatus disclosed in Patent Document 2 is disclosed as a technique for preventing distortion characteristic deterioration by controlling a bias circuit of a Doherty amplifying apparatus. FIG. 4 is a circuit diagram showing a configuration summarizing the power amplifying device disclosed in Patent Document 2. In the circuit configuration of the power amplifying device shown in FIG. 4, in addition to the circuit configuration of the Dono and Tee amplifying device in FIG. 1, a power bra 9 for extracting a signal so as not to reduce the gain of the input RF signal 9, The configuration includes a detector 10 for detecting input power, a first bias control unit 11, and a second bias control unit 12. According to such a configuration, the active bias is such that the biases of the first bias control unit 11 and the second bias control unit 12 change substantially proportionally as the input power detected by the detector 10 increases. Implement a bias circuit.

That is, in the power amplifying device shown in FIG. 4 described in Patent Document 2, as the input power increases, the first bias controller 11 reduces the bias of the carrier amplifier 2 and the second bias. Since the control unit 12 increases the bias of the peak amplifier 3, as shown in the characteristic (c) of Patent Document 2 of the alternate long and short dash line in FIG. Although the efficiency is low, in the high power mode it is more efficient than the class AB amplifier characteristics (b). In this way, low distortion characteristics can be maintained while maintaining a relatively high efficiency in the range of the low power mode and the high power mode.

Special Reference 1: RF Power Amplifiers for Wireless Communications, STEVE. CRIP

PS.Artech House Publishers

Patent Document 1: Japanese Unexamined Patent Application Publication No. 2004-173231

Patent Document 2: Special Table 2000-513535

Disclosure of the invention

Problems to be solved by the invention However, when the power amplifying apparatus as shown in FIG. 2 described in Patent Document 1 described above is applied to a mobile terminal, the dynamic range is widened, so that the balance is maintained in the high power mode that is frequently used. It becomes an amplifier (Class AB amplifier). In other words, when the efficiency decreases in the high power mode area where the frequency of use is high, a malfunction occurs.

Furthermore, in the power amplifying apparatus as shown in FIG. 4 described in Patent Document 2 above, the detector 10 for detecting the input power, the first bias control unit 11 and the second noisy control unit 12. Since the circuit scale becomes large due to the complexity of the configuration and the increase in the number of adjustment points of the analog circuit, such a power amplifier is not available for portable terminals intended for miniaturization. It becomes extremely difficult to implement.

[0013] In addition, in a multi-mode mobile terminal, the modulation scheme of the multi-carrier signal to be transmitted changes, so that when the peak factor of the multi-carrier signal becomes large, the balance amplifier (AB Even if it operates as a class amplifier), the low distortion characteristics cannot be maintained, and as a result, there is a problem that the distortion in the power amplifying device deteriorates. For example, in situations where the peak factor of a multicarrier signal changes, such as switching between R99 and Rel5 in WCDMA (Wideband Code Division Multiple Access) or switching between QPSK (Quadri Phase Shift Keying) and 16QAM (16 Quadrature Amplitude Modulation). Since it is impossible to maintain low distortion, such a power amplifying device cannot be used for a multi-mode portable terminal. Furthermore, since the operating region of the amplifying element varies depending on the ambient temperature of the mobile terminal, it is impossible to maintain low distortion characteristics over a wide power range.

An object of the present invention is to provide a high-efficiency and low-distortion power amplifying apparatus that can be applied to a mobile terminal, particularly a multi-carrier mobile terminal.

Means for solving the problem

[0015] A power amplifying apparatus of the present invention is a power amplifying apparatus that branches an input signal and performs power amplification by a Doherty amplification function using a carrier amplifier and a peak amplifier. The bias voltage control means for controlling the bias voltage or the bias current of the peak amplifier is used. According to such a configuration, the optimum bias voltage corresponding to the output power without using a complicated circuit is increased in peak. Since it can be applied to the width device, a low distortion and high efficiency power amplifier can be easily realized.

The invention's effect

[0016] According to the power amplifying device of the present invention, based on the TPC set value, the balance amplifier (AB) is set by setting the noise value of the peak amplifier so that the distortion characteristic falls below a predetermined threshold. Class amplification). This makes it possible to use the TPC setting value of the variable gain amplifier that allows the mobile terminal to perform transmission power control over a high dynamic range, thereby improving efficiency and reducing distortion without adding a complicated circuit. Can be realized.

[0017] Further, according to the power amplifying device of the present invention, the relationship between the TPC set value and the bias value of the peak amplifier whose distortion characteristic falls below a predetermined threshold is set by the TPC set value. With the transmitted power, the ACLR characteristics are set to the minimum bias value that is less than the standard value. Therefore, the distortion characteristics can be satisfied and the high-efficiency operation of the Doherty amplifier can be maintained.

[0018] Further, according to the power amplifying device of the present invention, when the TPC set value is the maximum value, the noise value of the peak amplifier is made equal to or less than the bias value of the carrier amplifier. . Therefore, at the time of maximum output, both the peak amplifier and the carrier amplifier have a configuration close to a balance amplifier as a class AB amplifier, so that the maximum output power can be achieved with low distortion while maintaining a state close to saturation power. In addition, highly efficient operation can be realized. Therefore, the power amplifying apparatus of the present invention can be applied to a portable terminal that can transmit a radio signal with high efficiency and low distortion.

Brief Description of Drawings

[0019] [Fig. 1] Schematic configuration diagram of commonly known Dono and Tee amplifiers

FIG. 2 is a circuit diagram showing a configuration summarizing the power amplifying device disclosed in Patent Document 1.

[FIG. 3] Characteristic diagram showing the relationship between output power and efficiency in the power amplifying device shown in FIG. 2 回路 4] Circuit diagram showing a configuration summarizing the power amplifying device disclosed in Patent Document 2

FIG. 5 is a configuration diagram of a power amplification device applied to Embodiment 1 of the present invention.

6 is a diagram showing an example of a table stored in the bias value table shown in FIG.

FIG. 7 is a characteristic diagram showing the relationship between output power and distortion in the power amplifying apparatus shown in FIG. FIG. 8 is a characteristic diagram showing the relationship between output power and efficiency in the power amplifying apparatus shown in FIG.

FIG. 9 is a circuit diagram showing the configuration of the carrier amplifier shown in FIG.

FIG. 10 is a circuit diagram showing the configuration of the peak amplifier shown in FIG.

FIG. 11 is a configuration diagram of a power amplifying device applied to Embodiment 2 of the present invention.

FIG. 12 is a configuration diagram of a power amplifying device applied to Embodiment 3 of the present invention.

FIG. 13 is a configuration diagram of a power amplifying device applied to Embodiment 4 of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

The power amplifying apparatus of the present invention obtains a noise value of a peak amplifier that maximizes efficiency while satisfying a desired low distortion condition in advance, and uses the transmission power control set value (TPC set value) to determine the peak amplifier. The bias value is switched. That is, the bias value of the peak amplifier is controlled according to the TPC setting value. As a result, the optimum bias value for the peak amplifier can be set according to the output power without using a complicated circuit, so that it can be applied over a wide power range from the low power mode to the high power mode. Therefore, high efficiency and low distortion can be realized.

[0021] In addition, the power amplifying apparatus of the present invention switches the bias value of the peak amplifier using a modulation mode such as a modulation scheme and the number of code multiplexes and a TPC setting value. As a result, it is possible to realize distortion characteristics with low distortion while maintaining high efficiency characteristics with respect to a signal having a large peak factor such as a multicarrier signal. Furthermore, a temperature detection unit is provided, and the temperature information detected by the temperature detection unit and the bias value of the TPC set value force peak amplifier are switched. As a result, even when the operating temperature of the power amplification device fluctuates, it is possible to achieve low distortion characteristics while maintaining high efficiency characteristics.

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

FIG. 5 is a configuration diagram of a power amplifying device applied to Embodiment 1 of the present invention. First, the configuration of the power amplification device shown in FIG. 5 will be described. This power amplifying device includes a modulation unit 1 01, frequency converter 102, variable gain amplifier 103, splitter 104, carrier amplifier 105, peak amplifier 106, first λλ4 transmission line 107, second λΖ4 transmission line 108, third λλ4 transmission line 109, A transmission power setting unit 110, a delay adjustment unit 111, a bias value table 112, and a bias setting unit (bias voltage control means) 113 are included.

In FIG. 5, the delay adjustment unit 111, the bias value table 112, and the bias setting unit 113 are components added according to the present invention, and other components are the conventional dono and tee amplification. Since these are the components of the power amplifying device realized by the device, description of those components will be made to the minimum necessary.

[0025] Modulation section 101 has a function for modulating the input baseband signal.

The frequency conversion unit 102 has a function of performing RFZIF conversion on the modulated baseband signal. The variable gain amplifier 103 has a function of pre-amplifying the RF signal or IF signal before the Doherty amplifier. The splitter 104 has a function of branching the RF signal or IF signal input to the Doherty amplifier.

[0026] The configuration subsequent to the splitter 104 is a configuration that realizes the Doherty amplification function, and the carrier amplifier 105 has a low input power and is highly efficient because it operates in a region with a high load impedance. It has a function to operate. The peak amplifier 106 is a signal having a high peak power by raising the saturation power while maintaining high efficiency because the load impedance viewed from the carrier amplifier 105 is lowered by the output current of the peak amplifier 106 in a region where the input power is high. Even if it exists, it has a function to perform highly efficient amplification. The first λ Ζ4 transmission line 107, the second λ Ζ4 transmission line 108, and the third λ Ζ4 transmission line 109 are transmission lines for delaying the phase of the input RF signal by 90 °.

[0027] Transmission power setting section 110 has a function of switching the bias values of variable gain amplifier 103 and peak amplifier 106 and setting TPC setting values for controlling the gains of these amplifiers to desired values. . The delay adjustment unit 111 has a function of adjusting the delay of the signal from the variable gain amplifier 103 to the peak amplifier 106. More specifically, the delay adjustment unit 111 includes a variable gain amplifier 103 → splitter 104 → second λΖ4 transmission line 108. → A function of absorbing the delay difference between the delay of the signal up to the peak amplifier 106 and the delay of the signal of the bias circuit from the bias value table 112 → the bias setting unit 113 → the peak amplifier 106.

[0028] The bias value table 112 stores a database indicating the relationship between the TPC setting value set by the transmission power setting unit 110 and the minimum bias setting value of the peak amplifier 106 that satisfies the distortion condition at that time. . That is, it has a function of selecting a bias setting value that can realize high-efficiency operation while satisfying the distortion condition at a desired transmission power, and outputting the selected bias setting value to the noise setting unit 113. FIG. 6 is a diagram showing an example of a table stored in the bias value table 112 shown in FIG. The bias setting unit 113 includes a variable voltage conversion unit (not shown) of the bias circuit of the peak amplifier 106 in order to realize an intended bias value based on the noise setting value output from the bias value table 112. A function for outputting a control signal is provided. A detailed description of the bias value table in FIG. 6 will be described later.

Next, the operation of the power Doherty amplifier for explaining the operation of the power amplifying device shown in FIG. 5 is a well-known technique, so that the explanation thereof will be omitted and will be described in detail mainly on the portion related to the present invention. The gain of the variable gain amplifier 103 is controlled by the TPC setting value set by the transmission power setting unit 110, and is input to the splitter 104 at the input stage of the Dono / tee amplification function to control the power gain. At this time, the information of the TPC set value set by the transmission power setting unit 110 is branched into a system to the variable gain amplifier 103 and a system to the delay adjustment unit 111. The information of the TPC set value input to the system of the delay adjustment unit 111 is subjected to delay adjustment by the delay adjustment unit 111, and then is biased by the bias value tape node 112 which is a bias circuit of the peak amplifier 106. .

[0030] At this time, the bias value table 112 has the highest efficiency while the Doherty amplification function satisfies a desired distortion characteristic under the power condition determined based on the TPC setting value set by the transmission power setting unit 110. The bias value of the peak amplifier 106 is stored. Therefore, when input to the bias setting signal force bias setting unit 113 output from the bias value table 112, the bias setting unit 113 sets the peak amplifier 106 so that the maximum amplification efficiency can be obtained with a desired distortion characteristic. Control the bias. FIG. 7 is a characteristic diagram showing the relationship between output power and distortion in the power amplifying apparatus shown in FIG. 5, with the horizontal axis representing output power and the vertical axis representing distortion. In other words, the characteristics of the four broken lines in FIG. 7 are the distortion characteristics when the bias of the peak amplifier 106 is switched, and show that the distortion increases along the vertical axis. In other words, the lower the level of the vertical axis, the smaller the distortion (low distortion). FIG. 8 is a characteristic diagram showing the relationship between output power and efficiency in the power amplifying apparatus shown in FIG. 5, with the horizontal axis representing output power and the vertical axis representing efficiency.

As shown in FIG. 7, by gradually switching the bias value of the peak amplifier 106 so as to approach the balance amplifier in the high power mode, the distortion characteristic can be improved. As indicated by the dotted points a, b, c, and d, the level of distortion remains below the threshold. Note that the output power at points X and Y at which the distortion characteristics at the respective bias values reach the threshold is the linear maximum output power that satisfies the distortion condition.

[0033] As shown in Fig. 8, the efficiency of the power amplifier decreases from the high efficiency of the Doherty amplifier in the low power mode to the efficiency of the balance amplifier (Class AB amplifier) in the high power mode. Since the bias value of the peak amplifier 106 is switched step by step so that the level of the current does not exceed the threshold, the efficiency of the Norrance amplifier (class AB amplifier) does not decrease so much. In other words, as shown in Fig. 7, the bias value that maximizes the efficiency should be selected under the condition that the distortion levels a, b, c, d at each bias value are less than the preset threshold. Thus, as shown in Fig. 8, the efficiency is lower than that of the original Doherty amplifier, but the efficiency can be improved as compared with the balance amplifier (Class AB amplifier). Note that the efficiency of the balance amplifier in the high power mode in Fig. 8 is as follows. The efficiency can be made almost constant as shown by the dashed line in the figure.

In other words, since the balance amplifier has better linearity in the high power mode region, the bias value of the peak amplifier 106 is gradually closer to the balance amplifier (class AB amplifier) so that the distortion level falls below the threshold. Bias control is performed so that In other words, the bias that brings the bias condition of the peak amplifier 106 closer to the bias condition of the carrier amplifier 105 Take control. In this way, when the high power mode is entered, instead of turning the peak amplifier 106 into a balance amplifier (class AB amplifier) all at once, gradually increasing the bias level of the peak amplifier 106 gradually increases the balance amplifier ( This makes it possible to increase the linear maximum output power while producing the high efficiency characteristics of the Doherty amplification function. As a result, it is possible to achieve a higher efficiency than that of a balanced amplifier, and to achieve a lower back-off than a simple Donotty amplifier.

FIG. 9 is a circuit diagram showing a configuration of carrier amplifier 105 shown in FIG. The carrier amplifier 105 includes a transistor 121, an input matching circuit 122 for inputting an RF signal, a gate bias circuit 123 for covering the first gate bias, a power circuit 124 for covering the drain power source, and an output matching circuit 125. Since this is the same as that of the conventional carrier amplifier, its description is omitted. Note that the transistor 121 may be a bipolar transistor such as a force HBT that uses an FET in this example. In that case, the gate bias voltage is the base bias current.

FIG. 10 is a circuit diagram showing a configuration of peak amplifier 106 shown in FIG. The peak amplifier 106 in FIG. 10 is different from the carrier amplifier in FIG. 9 in that a variable voltage converter 126 is added to the gate bias circuit 123, and the variable voltage converter 126 is connected to the second gate bias based on the bias control signal. In other words, the noise voltage applied to the gate of the transistor 121 is changed by controlling the above. In this way, by changing the bias voltage of the transistor 121, the bias of the peak amplifier 106 is controlled to gradually approach the balance amplifier (class AB amplifier) while keeping the distortion level below the threshold. is doing. The transistor 121 may be a bipolar transistor such as a force HBT that uses an FET in this example. In that case, the gate bias voltage becomes the base bias current.

[0037] Returning to Fig. 6 again, the bias value table will be described in detail. This bias value table includes a TPC setting value set by the transmission power setting unit 110, a noise value biased to the peak amplifier 106, and a bias setting for setting the bias value of the peak amplifier 106 to a desired value. The relationship with values is represented in a table. For example, if the TPC setting value set in the transmission power setting section 110 is negative (−50 to −lOdBm), the bias value is set to OV. Therefore, the bias setting value in the bias value table 112 is set to 0. That is, the bias supplied from the noise setting unit 113 to the peak amplifier 106 is set to zero, the peak amplifier 106 is turned off, and the carrier amplifier 105 is operated as a Dono / tee amplifier.

In addition, when the TPC set value set by transmission power setting section 110 is a positive value from 0 to 22 dBm, the bias value table 112 is biased to change the bias value from 0.02 to 0.26 V. Switch the set value in steps from 1 to 13. As a result, the bias level applied from the bias setting unit 113 to the peak amplifier 106 increases stepwise, so that the amplification characteristics of the peak amplifier 106 approach the class AB amplifier of the carrier amplifier 105. When the TPC set value set by the transmission power setting unit 110 becomes 24 dBm or more, the bias set value in the bias value table 112 is fixed to 15 in order to keep the bias value constant at 0.30 V. . That is, the maximum value of the bias value of the peak amplifier 106 is set to be equal to or less than the bias value of the carrier amplifier 105. In other words, when the bias values of the carrier amplifier 105 and the peak amplifier 106 become equal, the entire power amplifying apparatus becomes a balance amplifier.

FIG. 11 is a configuration diagram of a power amplifying device applied to Embodiment 2 of the present invention. The difference between the power amplifying device of the second embodiment shown in FIG. 1 and the power amplifying device of the first embodiment shown in FIG. 5 is that a temperature detection unit (temperature detection means) 114 is added to the noise value table 112. This is the point where temperature information is input. Therefore, only the parts different from the power amplifying apparatus of the first embodiment shown in FIG. 5 will be described.

In FIG. 11, temperature detector 114 detects the operating temperature of the power amplifier, and inputs the operating temperature of the power amplifier to bias value table 112 together with the TPC set value set by transmission power setting unit 110. As a result, the bias value of the peak amplifier 106 is controlled by the bias setting unit 113 so that the distortion is kept below the threshold value even if the distortion of the power amplifier is caused by the temperature fluctuation.

In this way, the temperature detection unit 114 detects the operating temperature of the power amplifier and corrects the setting value of the bias value table 112, thereby preventing distortion characteristics from being deteriorated due to temperature fluctuation of the power amplifier. Can do. In this case, the bias value can be corrected by having the bias value table shown in Fig. 6 for each temperature, and the TPC set value and temperature can be corrected. The bias value can be corrected by obtaining the reference address of the force bias value table. In the latter case, you should have one noise value table.

FIG. 12 is a configuration diagram of a power amplifying device applied to Embodiment 3 of the present invention. The power amplifying device of Embodiment 3 shown in FIG. 12 differs from the power amplifying device of Embodiment 1 shown in FIG. 5 in that a power deviation table (between the transmission power setting unit 110 and the variable gain amplifier 103 ( (Power deviation means) 115 is added.

That is, by controlling the bias of the peak amplifier 106 according to the value of the TPC set value set by the transmission power setting unit 110, the gain of the entire power amplifying device changes, so that the TPC set value is set. There is a possibility that a deviation occurs between the power based on the power based on the RF signal input to the modulation unit 101. Accordingly, the deviation is investigated in advance, and the TPC setting value (that is, the variable gain control installation value) input to the variable gain amplifier 103 is corrected by the power deviation table 115. Thereby, even if the bias of the peak amplifier 106 is controlled, the output power of the power amplifying device can be set to the intended power.

That is, since the gain of the peak amplifier 106 changes by changing the bias of the peak amplifier 106, it is necessary to compensate for the change in the gain. Therefore, a power deviation table 115 is provided for changing the gain control setting value of the variable gain amplifier 103 in accordance with the TPC setting value of the transmission power setting unit 110. As a result, the power deviation table 115 can adjust the set value of the variable gain amplifier 103 to an optimum value. In addition, when the bias value table 112 is created after considering the power deviation table 115 in the transmission power setting unit 110, the power deviation table 115 may not be provided separately. The configuration in that case is the same as the configuration in FIG.

FIG. 13 is a configuration diagram of a power amplifying device applied to Embodiment 4 of the present invention. The difference between the power amplifying device in the fourth embodiment shown in FIG. 13 and the power amplifying device in the first embodiment shown in FIG. 5 is that the configuration for inputting the modulation method switching signal 116 to the bias value table 112 has been added. Is a point. In other words, if the modulation method changes, the peak factor of the transmission power changes and the distortion characteristics change. Therefore, the modulation method switching signal (modulation method switching information detecting means) 116 The bias value is changed to compensate for the change in distortion characteristics.

In other words, the power amplifying apparatus of the fourth embodiment inputs the modulation scheme switching signal 116 inputted with the baseband unit power to the bias value table 112 and transmits it by the transmission power setting unit 110 (not shown). Based on the TPC setting value and the modulation system switching signal 116, the bias characteristic of the peak amplifier 106 is switched to compensate for distortion characteristics caused by the peak factor that varies depending on the modulation system.

[0047] In this way, even when the modulation method changes, by switching the selection of the bias value according to the peak factor at that time, it is possible to prevent the distortion characteristics from deteriorating even when the peak factor changes. . As a result, even when the peak factor increases, the maximum linear output power with low distortion can be maintained while maintaining the high efficiency characteristics of the Donotty amplifier.

Industrial applicability

[0048] The power amplifier of the present invention can be effectively used for a mobile communication terminal such as a mobile terminal capable of transmitting a radio signal with high efficiency and low distortion.

Claims

The scope of the claims

[1] A power amplifying device for branching an input signal and performing power amplification by a Doherty amplification function by a carrier amplifier and a peak amplifier,

Baseband signal power A power amplifying apparatus comprising bias voltage control means for controlling a bias voltage or a bias current of the peak amplifier using an extracted control signal.

[2] The power amplification device according to [1], wherein the control signal is a transmission power control setting value for controlling a bias voltage of the peak amplifier so that amplification efficiency is maximized while satisfying a desired distortion characteristic. .

3. The power amplifying apparatus according to claim 2, wherein the transmission power control set value is prepared in advance as a bias value table corresponding to the bias voltage of the peak amplifier.

4. The power amplifying apparatus according to claim 2, wherein the transmission power control set value is a value at which a maximum value of the bias voltage of the peak amplifier is equal to or less than a bias voltage of the carrier amplifier.

[5] The apparatus further comprises temperature detection means for transmitting temperature information detected by itself to the bias value table and correcting the transmission power control setting value corresponding to the bias voltage of the peak amplifier based on the temperature information. Item 4. The power amplifying device according to Item 3.

[6] Modulation scheme switching for transmitting transmission power modulation scheme switching information to the bias value table and correcting the transmission power control setting value corresponding to the bias voltage of the peak amplifier based on the modulation scheme switching information The power amplifying apparatus according to claim 3, further comprising information detecting means.

[7] The power amplifying device according to claim 3, further comprising power deviation means for controlling a bias voltage of a variable gain amplifier preceding the carrier amplifier and the peak amplifier in accordance with the transmission power control setting value. .