JP2008109184A - Source voltage control method and device for amplifier - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a source voltage control method and device with excellent responsiveness that controls the source voltage of an amplifier so that the power consumption is minimum while satisfying distortion characteristics of the amplifier. <P>SOLUTION: Prepared is a table 106 containing source voltage set values of the amplifier 14 corresponding to respective transmission power values under reference signal conditions. A transmission power specifying unit 101 specifies a transmission power value P<SB>T</SB>, and a back-off calculating unit 103 calculates a back-off value P<SB>B</SB>needed for the amplifier according to signal conditions of a signal to be transmitted. An adder 104 adds those together, and a source voltage, corresponding to the addition value (P<SB>T</SB>+P<SB>B</SB>), in the table 106 is determined by using the addition value and set as the source voltage Vcc of the amplifier 14. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to amplifier power supply control, and more particularly to an amplifier power supply voltage control method and apparatus for amplifying a signal whose peak factor changes.

  In mobile communication systems that employ high-speed packet transmission methods such as HSDPA (High Speed Downlink Packet Access) and HSUPA (High Speed Uplink Packet Access), a technology called multicode is used to multiplex multiple codes on one channel. Has been. In the case of this multi-code, the peak factor of transmission power (ratio of peak power to average power) varies with the increase / decrease in the number of multiplexing, so ensuring linearity of power amplifiers used in wireless circuits is a problem. It has become.

  For example, if the power amplifier power supply voltage is set based on the peak factor when the number of multiplexing is small, the linearity of the power amplifier cannot be secured and the distortion characteristics deteriorate when the peak factor increases with the increase in the number of multiplexing. Resulting in. Conversely, if the power supply voltage of the power amplifier is set high in advance so as to ensure the distortion characteristics even if the peak factor varies, the power consumption is wasted when the peak factor becomes small. In particular, waste of power consumption must be avoided in battery-powered mobile stations. Various proposals have been made for such a trade-off between ensuring the linearity of a radio circuit and power consumption.

  In Japanese Patent Application Laid-Open No. 2004-120271 (Patent Document 1), the output power of a high-power amplifier is monitored, the back-off power is determined based on this power information, and the output is high so that the determined back-off power is obtained. A wireless transmitter for adjusting the output of an amplifier is disclosed (paragraphs 0010, 0011, FIGS. 1 and 3).

  In JP 2005-318266 A (Patent Document 2), when the number of multiplexed waves increases, the bias voltage of the transmission power amplifier is controlled according to the gain factor (amplitude coefficient) of the added channel. A transmission power control method that optimizes linearity is disclosed (paragraphs 0015 to 0018, FIGS. 2 and 4).

JP 2004-120271 A (paragraphs 0010 and 0011, FIGS. 1 and 3) JP 2005-318266 A (paragraphs 0015 to 0018, FIGS. 2 and 4)

  The wireless transmitter described in Patent Document 1 is based on feedback control in which backoff power is determined based on currently output power, and power with high accuracy and good response to a signal to be transmitted from now on. Control cannot be performed.

  In the transmission power control method described in Patent Literature 2, the correlation between the change amount of the peak factor and the gain factor is used, so to speak, the transmission power is adjusted based on feedforward control. However, in order to cope with the change of the peak factor according to the gain factor by changing the correction amount V_mod_offset of the bias voltage in a plurality of steps, it is not possible to perform power control with good responsiveness.

  An object of the present invention is to provide a power supply voltage control method and apparatus with good responsiveness that control the power supply voltage of an amplifier so as to minimize power consumption while satisfying the distortion characteristics of the amplifier.

  According to the present invention, a backoff value necessary for the amplifier is designated from a signal condition of a signal to be transmitted, and a corrected transmission power value obtained by adding the designated backoff value to a given transmission power value is used. The power supply voltage corresponding to the corrected transmission power value is determined from the correspondence between the predetermined transmission power and the power supply voltage value to be supplied to the amplifier, and set as the power supply voltage of the amplifier that amplifies the high-frequency transmission signal. To do.

  A power supply voltage setting value of the amplifier corresponding to each transmission power value under a reference signal condition is prepared as a table, for example. The reference signal is a signal having the smallest peak factor, for example, the number of multiplexed signals is one. Further, it is assumed that the power supply voltage setting value of the memory is optimized so that the power consumption is minimized while satisfying the distortion characteristics at each transmission power value of the reference signal.

  In the state where the reference signal is transmitted, the power supply voltage setting value of the amplifier corresponding to the transmission power is read from the table and set in the DC-DC converter. Now, when the transmission signal is changed from the reference signal to a signal with a large peak factor, the back-off calculation unit calculates the amplifier back-off necessary for the next signal in advance, and the power supply voltage setting value is A value corresponding to a value obtained by adding a back-off value to the transmission power to be output is selected from the table and used.

  According to the present invention, the power supply voltage of the amplifier is specified using the corrected transmission power value that specifies the backoff value from the signal condition of the signal to be transmitted and adds the specified backoff value to the given transmission power value. By setting, it is possible to always set an optimized power supply voltage of the amplifier while suppressing deterioration of distortion characteristics of the amplifier regardless of how the peak factor changes. In particular, by storing the power supply voltage setting value of the amplifier corresponding to each transmission power value in the reference signal condition in the table, it is sufficient to prepare one table for the reference signal, which increases the circuit scale. It can be suppressed, and control complexity can be avoided.

1. 1. First Embodiment 1.1) Device Configuration FIG. 1 is a schematic block diagram of a wireless communication device equipped with a power supply voltage control device according to a first embodiment of the present invention. The wireless communication apparatus is provided with a digital baseband processing unit 10 that executes power supply voltage control and other controls according to the present embodiment, and exchanges transmission / reception data with the analog baseband processing unit 11. The analog baseband processing unit 11 receiving the transmission data outputs a transmission IQ signal to the quadrature modulator 12, and the quadrature modulator 12 performs quadrature modulation of the carrier with the transmission IQ signal. Unnecessary frequency components are removed from the output of the quadrature modulator 12 by a bandpass filter (BPF) 13, and the power amplifier 14 finally amplifies the necessary power to transmit a transmission RF signal to a base station (not shown). To do.

The power amplifier 14 is supplied with the power supply voltage Vcc from the DC-DC converter 15. The DC-DC converter 15 can change the power supply voltage Vcc according to the control voltage V _CTRL from the digital baseband processing unit 10. As will be described later, the digital baseband processing unit 10 uses the memory 16 to control the power supply voltage Vcc so that the power consumption is minimized while satisfying the distortion characteristics by ensuring the linearity of the power amplifier 14. .

1.2) Power Supply Voltage Control The power supply voltage control of the power amplifier 14 according to the present embodiment is executed by the digital baseband processing unit 10. The functions of the digital baseband processing unit 10 can be realized by birdware, but can also be realized by executing a program on a program control processor such as a CPU.

The digital baseband processing unit 10 is provided with a transmission power specifying unit 101 and a signal condition specifying unit 102, and when the signal condition of the transmission RF signal is changed according to a command from the base station, a signal to be transmitted next Transmission power and signal information necessary for back-off calculation are respectively generated. That is, transmission power designation section 101 outputs transmission power designation value P _T , and signal condition designation section 102 outputs signal condition information to be transmitted next time to backoff calculation section 103 in accordance with the change in signal condition.

When the back-off calculating unit 103 receives information on a signal condition to be transmitted next time from the signal condition specifying unit 102, the back-off calculating unit 103 calculates a back-off value P _B necessary for the power amplifier 14 based on the information. The back-off value P _B of the power amplifier can be obtained based on the peak factor determined from the number of multiplexed signals, the power ratio of each channel, the configuration of the IQ signal, and the like. For example, the correspondence between changes in the number of multiplexed signals and channel power ratio and changes in the back-off value P _B may be stored in a table format in advance.

The transmission power designation value P _T and the back-off value P _B obtained in this way are added by the adder 104, and the result (P _T + P _B ) is output to the power amplifier power supply voltage control unit 105. The power supply voltage control unit 105 determines the corresponding control voltage V _CTRL from the power supply voltage control table 106 stored in the memory 16 using the input addition value (P _T + P _B ) and outputs it to the DC-DC converter 15. . The memory 16 is a nonvolatile memory, for example.

The DC-DC converter 15 supplies a power supply voltage Vcc corresponding to the control voltage V _CTRL to the power amplifier 14. As described above, the power supply voltage Vcc is consumed while ensuring the linearity of the power amplifier 14 in consideration of the amount of change between the transmission power designation value P _T and the back-off value P _B accompanying the change in the signal condition. The power is set to be minimum.

1.3) Power Supply Voltage Control Table FIG. 2 is a diagram showing an example of the power supply voltage control table used in this embodiment. The power supply voltage control table 106 stores the control voltage value V _CTRL of the DC-DC converter corresponding to each transmission power in a table format. However, the DC-DC converter output voltage value in the third column in the figure is described for reference and is not actually required.

  The power supply voltage control table 106 preferably stores power supply voltage setting values corresponding to each transmission power value under a reference signal condition. The reference signal condition is, for example, a signal condition with the smallest peak factor such that the number of multiplexed signals is one. Under this reference signal condition, the power supply voltage Vcc is optimized so that the power consumption is minimized while satisfying the distortion characteristics at each transmission power value.

Using such a power supply voltage control table 106, the power supply voltage control unit 105 inputs an addition value (P _T + P _B ) of the transmission power designated value P _T and the backoff value P _B as “transmission power”, The corresponding control voltage V _CTRL is read from the power supply voltage table 106 and set as the control voltage of the DC-DC converter 15.

For example, if the transmission power designation value P _T is +20 dBm and the back-off value P _B is +5 dB, the power supply voltage control table 106 is searched with the added value +25 dBm as “transmission power”, and the control voltage value V corresponding to that value 0.75 V is output to the DC-DC converter 15 as _CTRL . The DC-DC converter 15 to which the control voltage value V _CTRL = 0.75V is input supplies the power supply voltage Vcc corresponding thereto to the power amplifier 14.

1.4) Example of operation Currently, the signal condition having the smallest peak factor is designated based on the command from the base station, and the power is determined according to the added value of the corresponding backoff value P _B and transmission power designated value _PT. It is assumed that the power supply voltage Vcc of the amplifier 14 is determined and the transmission RF signal is amplified.

When there is a signal condition change command from the reference state, first, the signal condition designating unit 102 notifies the back-off calculating unit 103 of the updated signal condition. The back-off calculation unit 103 immediately determines the back-off value P _B necessary for the power amplifier 14 from the notified condition, and outputs it to the adder 104.

The adder 104 adds the back-off value P _B output from the back-off calculation unit 103 and the transmission power designation value P _T output from the transmission power designation unit 101, and sends the addition value to the power supply voltage control unit 105. Output. The power supply voltage control unit 105 reads the control voltage value V _CTRL corresponding to the added value from the power supply voltage control table 106 and outputs it to the DC-DC converter 15. As a result, the power supply voltage Vcc meeting the updated signal condition is supplied to the power amplifier 14.

On the other hand, the analog baseband processing unit 11 also changes the signal condition, outputs the changed transmission IQ signal to the quadrature modulator 12, and the power of the modulated carrier signal is amplified by the power amplifier 14 through the bandpass filter 13. The RF signal after the signal condition change is input to the power amplifier 14, and at the same time, the power supply voltage Vcc meeting the updated signal condition is supplied from the DC-DC converter 15 to the power amplifier 14. These timings can be adjusted by the digital baseband processing unit 10 that outputs both the transmission data and the control voltage _VCTRL .

  In this way, the power amplifier 14 is supplied with the power supply voltage Vcc in consideration of the back-off to the transmission power of the RF signal to be actually transmitted. Therefore, the transmission RF signal satisfies the distortion characteristics and has low power consumption. can do.

2. Second Embodiment In the first embodiment described above, the linearity of the power amplifier 14 is ensured by taking into account the reduction in power consumption by controlling the power supply voltage Vcc of the power amplifier 14, but according to the second embodiment, The driver amplifier that amplifies the quadrature-modulated RF signal similarly performs power supply voltage control, thereby further reducing power consumption.

FIG. 3 is a schematic block diagram of a wireless communication device in which the power supply voltage control device according to the second embodiment of the present invention is mounted. Note that blocks having the same functions as those of the apparatus of the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted. In FIG. 3, the quadrature modulator 12 includes, as is well known, a multiplier that multiplies carrier signals that are orthogonal to the I signal and Q signal, and an adder that adds the modulated carrier signals after multiplication. Further, this quadrature modulation output is amplified by a driver amplifier 107. The power supply voltage V _DCC of the driver amplifier 107 is supplied from the DC-DC converter 203 under the control of the power supply voltage control unit 201 of the digital baseband processing unit 10.

The memory 16 stores a power supply voltage control table 202 for the driver amplifier 107 in addition to the power supply voltage control table 106 for the power amplifier 14 described above. Similarly to the power supply voltage control table 106, the power supply voltage control table 202 stores the control voltage value V _{CTRL-DA of} the DC-DC converter 203 corresponding to each transmission power under the reference signal conditions in a table format. . Under this reference signal condition, the power supply voltage V _DCC is optimized so that the power consumption is minimized while satisfying the distortion characteristics of the driver amplifier 107 at each transmission power value.

Using such power supply voltage control tables 106 and 202, power supply voltage control section 105 inputs an addition value (P _T + P _B ) of transmission power designated value P _T and backoff value P _B as “transmission power”. Then, the control voltage V _CTRL for the power amplifier 14 and the control voltage value V _CTRL-DA for the driver amplifier 107 are read out and set as control voltages for the DC-DC converters 15 and 203, respectively.

3. Third Embodiment In the first embodiment described above, when the back-off calculating unit 103 receives information on the signal condition to be transmitted next time from the signal condition designating unit 102, the back-off value P _B required for the power amplifier 14 based on the received signal condition information. However, according to the third embodiment, the accuracy of the back-off value P _B is further improved by considering the temperature characteristic and the frequency characteristic of the power amplifier 14, thereby enabling lower power consumption.

  FIG. 4 is a schematic block diagram of a wireless communication device in which the power supply voltage control device according to the third embodiment of the present invention is mounted. Note that blocks having the same functions as those of the apparatus of the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted. In FIG. 4, the digital baseband processing unit 10 in this embodiment is further provided with a temperature / frequency correction value calculation unit 301. The temperature / frequency correction value calculation unit 301 holds the temperature characteristics and frequency characteristics of the power amplifier 14 in the form of a table or a calculation formula in advance, but these tables may be stored in the nonvolatile memory 16.

In the present embodiment, a temperature sensor (not shown) that measures the temperature of the power amplifier 14 is provided. The temperature / frequency correction value calculation unit 301 inputs the measured temperature and the frequency of the signal to be transmitted, calculates a back-off correction value using the stored temperature characteristic and frequency characteristic, and calculates the back-off. Output to the unit 103. As described above, the back-off calculation unit 103 calculates the back-off value based on the signal condition, corrects the calculated back-off value with the back-off correction value, and adds the result as the back-off value P _B. Output to the device 104. Thus, by taking into account the temperature characteristics and frequency characteristics of the power amplifier 14, the accuracy of the back-off value P _B can be further improved and the power consumption can be further reduced.

4). Fourth Embodiment The power supply voltage control unit 105 or 201 in the first to third embodiments described above uses the input addition value (P _T + P _B ) to store the power supply voltage control table 106 or 202 stored in the memory 16. The corresponding control voltage is determined and output to the DC-DC converter 15 or 203. However, according to the fourth embodiment, the calculated value of the DC-DC converter is calculated from the added value (P _T + P _B ) using a calculation formula instead of a table. Determine the control voltage.

FIG. 5 is a schematic block diagram of a wireless communication device in which the power supply voltage control device according to the fourth embodiment of the present invention is mounted. Note that blocks having the same functions as those of the apparatus of the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted. In FIG. 4, the digital baseband processing unit 10 in this embodiment is provided with a power supply voltage control unit 401 for the power amplifier 14, and the control voltage value V _CTRL is defined as a function f of the added value (P _T + P _B ). ing. Therefore, when the addition value (P _T + P _B ) is input from the adder 104, the corresponding control voltage value V _CTRL can be immediately output to the DC-DC converter 15 by calculation.

  INDUSTRIAL APPLICABILITY The present invention can be applied to a power supply voltage control device for a power amplifier for transmission power amplification in a transmitter whose transmission power peak factor may vary, and can be applied to a wireless communication device such as a mobile terminal having such a transmitter. It is.

It is a schematic block diagram of the radio | wireless communication apparatus which mounted the power supply voltage control apparatus by 1st Embodiment of this invention. It is a figure which shows an example of the power supply voltage control table used by this embodiment. It is a schematic block diagram of the radio | wireless communication apparatus which mounted the power supply voltage control apparatus by 2nd Embodiment of this invention. It is a schematic block diagram of the radio | wireless communication apparatus which mounted the power supply voltage control apparatus by 3rd Embodiment of this invention. It is a schematic block diagram of the radio | wireless communication apparatus which mounted the power supply voltage control apparatus by 4th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Digital baseband process part 11 Analog baseband process part 12 Quadrature modulator 13 Band pass filter 14 Power amplifier 15 DC-DC converter 16 for power amplifiers Memory 101 Transmission power designation | designated part 102 Signal condition designation part 103 Back-off calculation part 104 Addition Power amplifier power supply voltage control section 106 Power amplifier power supply voltage control table 107 Driver amplifier 201 Power amplifier / driver amplifier power supply voltage control section 202 Driver amplifier power supply voltage control table 203 Driver amplifier DC-DC converter 301 Frequency correction value calculation unit 401 Power amplifier power supply voltage control unit

Claims (14)

In a power supply voltage control apparatus for an amplifier that amplifies a high-frequency transmission signal whose peak factor can change,
A memory for storing a correspondence relationship between each predetermined transmission power and a power supply voltage value to be supplied to the amplifier;
Back-off designating means for designating a back-off value necessary for the amplifier from a signal condition of a signal to be transmitted;
Power supply voltage setting means for referring to the memory using a corrected transmission power value obtained by adding the back-off value to a given transmission power value and setting a power supply voltage corresponding to the corrected transmission power in the amplifier When,
A power supply voltage control apparatus for an amplifier, comprising:   2. The power supply voltage control apparatus for an amplifier according to claim 1, wherein the signal condition is a condition for changing a peak factor of the high-frequency transmission signal.   2. The power supply voltage control apparatus for an amplifier according to claim 1, wherein the correspondence relationship is a signal condition in which a peak factor is minimum.   2. The amplifier power supply voltage control apparatus according to claim 1, wherein the amplifier is a power amplifier for amplifying transmission power.   5. The power supply voltage control apparatus for an amplifier according to claim 4, wherein the amplifier is a driver amplifier provided in front of the power amplifier.   5. The power supply voltage control apparatus for an amplifier according to claim 4, wherein the power supply voltage setting means sets power supply voltages for both the power amplifier and the driver amplifier. A temperature / frequency correction value generating means for calculating a backoff correction value using the temperature characteristic and frequency characteristic of the amplifier;
2. The power supply voltage control apparatus for an amplifier according to claim 1, wherein the back-off designating unit corrects the back-off value by the back-off correction value. In a power supply voltage control method for an amplifier that amplifies a high-frequency transmission signal whose peak factor can change,
The correspondence between each predetermined transmission power and the power supply voltage value to be supplied to the amplifier is stored in the memory,
Specify the required back-off value for the amplifier from the signal condition of the signal to be transmitted,
A power supply voltage corresponding to the corrected transmission power value is supplied to the amplifier from the correspondence stored in the memory using the corrected transmission power value obtained by adding the back-off value to the given transmission power value. ,
A power supply voltage control method for an amplifier.   9. The power supply voltage of the amplifier according to claim 8, wherein a back-off correction value is calculated using temperature characteristics and frequency characteristics of the amplifier, and the back-off value is corrected by the calculated back-off correction value. Control method. In a program for causing a computer to execute power supply voltage control for an amplifier that amplifies a high-frequency transmission signal whose peak factor can change,
Designating the required back-off value for the amplifier from the signal conditions of the signal to be transmitted;
Using the corrected transmission power value obtained by adding the back-off value to the given transmission power value, the corrected transmission power value and the power supply voltage value to be supplied to the amplifier are determined from the correspondence relationship. Supplying a power supply voltage corresponding to a transmission power value to the amplifier;
The program characterized by having.   11. The method according to claim 10, further comprising a step of calculating a backoff correction value using temperature characteristics and frequency characteristics of the amplifier, and correcting the backoff value by the calculated backoff correction value. Program.   A wireless communication device comprising the power supply voltage control device according to claim 1.   A wireless communication apparatus having a digital baseband processing unit for executing the power supply voltage control method according to claim 8.   A wireless communication apparatus comprising a processor that executes the program according to claim 10.

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