JPH09321637A - Radio transmitter and control method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To compensate gain fluctuation of a high frequency power amplifier circuit in the case of switching transmission power in the radio transmitter of a transmission power control type. SOLUTION: A prescribed high frequency signal is supplied from a variable gain drive amplifier circuit 44. An operating state of a plurality of field-effect transistors(TRs) of a high frequency power amplifier circuit 45 is selected for each group by a bias control circuit 47 controlled by a transmission power control circuit 46 to select transmission power. The transmitter is provided with a compensation control circuit 48 including a generating means for compensation information to compensate a gain fluctuation of the high frequency power amplifier circuit in this switching and the compensation control circuit controls the gain of the drive amplifier circuit under the control of the transmission power control circuit 46.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission power control type wireless transmission device and a control method thereof, which are suitable for, for example, mobile phones.

[0002]

2. Description of the Related Art Conventionally, in many wireless communication devices such as mobile phones, transmission power control is performed in order to save power consumption and reduce interference with other stations. In such a wireless communication device, the transmission power control is performed by changing the drive signal level of the high frequency power amplifier circuit based on the reception signal level or the instruction signal from the partner station such as the base station. It is often done.

Further, in order to improve the efficiency of the high frequency power amplifier circuit at the time of low transmission output, there is a technique for controlling the DC power supplied from the power source to the high frequency power amplifier circuit according to the transmission power control information, for example. JP-A-1-314431
It is disclosed in Japanese Patent Publication No. 6-93631 and the like.

In these transmission power control methods, at the time of low transmission output, the drain current is changed by changing the gate voltage of the field effect transistor forming the high frequency power amplifier circuit or by reducing the drain voltage. The power consumption of the high frequency power amplifier circuit is reduced.

[0005]

However, since the gate voltage-drain current characteristic of the field-effect transistor is not an ideal linear characteristic, the above-mentioned transmission power control method causes a decrease in gain and distortion characteristics. Constrained by deterioration,
Even when the transmission power is low, there is a problem that the drain current of the field effect transistor cannot be reduced so much and the power consumption of the high frequency power amplifier circuit cannot be significantly reduced.

In order to solve such a problem, the applicant of the present invention filed a patent application (reference number S95) dated April 27, 1995.
021542) has already proposed a "high-frequency amplifier circuit, a transmitting device, and a receiving device" capable of significantly reducing power consumption at the time of low output.

In the already proposed high-frequency amplifier circuit, a plurality of field-effect transistors connected to the grounded source are divided into a plurality of groups, and each group has a plurality of DC blocking elements commonly connected to the gate of the field-effect transistor. The high-frequency signal from the input terminal is commonly supplied to the gates of all field-effect transistors through the capacitors.

In addition, the gate of the field effect transistor has a required gate bias voltage at which the field effect transistor is in an operating state or a non-operating state through a resistor for each group, for example, a transmission power from a base station. It is selectively supplied according to the instruction information.

The drains of the field effect transistors of each group are all connected in common, power is supplied through the high frequency choke coil, and the high frequency signal of each drain of the field effect transistors is led to the output terminal. The number of field effect transistors in each group does not necessarily have to be the same.

With the above-mentioned configuration, in the proposed high-frequency amplifier circuit, when the transmission output power is high, the field effect transistors of all groups are in the operating state, and when the transmission signal power is low, some The gate bias voltage of the group is switched to make it inactive.

As a result, in the proposed high-frequency amplifier circuit, for example, as shown by the curve Lp in FIG.
At a low output of 5 dBm or less, the gate bias voltage is appropriately switched so that almost half of the field effect transistors are in the operating state, and the drain current can be reduced to about 1/2 as a whole. At the time of low transmission output, the power consumption of the high frequency power amplifier circuit can be greatly reduced without a decrease in gain and deterioration of distortion characteristics.

However, in the already proposed high-frequency amplifier circuit as described above, when the output power is switched by controlling the operation or non-operation of the field effect transistor, for example,
As indicated by the curves Hp and Lp in FIG. 4, a gain variation of about 1.3 dB occurs, and the discontinuity of the gain affects the stability of the wireless communication device or the wireless line.

In view of the above point, an object of the present invention is to provide a radio transmitter and a control method thereof, which can compensate the gain variation of the high frequency power amplifier circuit when the output power is switched.

[0014]

In order to solve the above-mentioned problems, a first radio transmitting apparatus according to the present invention comprises a high-frequency power amplifying means including a plurality of active elements divided into a plurality of groups,
The information generating means for generating transmission power control information corresponding to the predetermined transmission power of the high frequency power amplifying means, and the operating state of the active element of the high frequency power amplifying means based on the transmission power control information from the information generating means. A radio transmission device comprising group control means for switching for each group and variable gain amplification means for supplying a predetermined high frequency signal to the high frequency power amplification means, the high frequency for switching the operating state of the active element for each group. Compensation control means for controlling the gain of the variable gain amplification means is provided based on the compensation information and the transmission power control information, including compensation information generation means for compensating the gain fluctuation of the power amplification means. Is.

According to a second aspect of the present invention, there is provided a method of controlling a radio transmitting apparatus, wherein a plurality of active elements of a high frequency power amplification means to which a predetermined high frequency signal is supplied from a variable gain amplification means are divided into a plurality of groups. A method for controlling a wireless transmission device in which the operating states of the active elements of the high-frequency power amplification means are switched for each group based on the transmission power control information corresponding to the transmission power of Compensation information for compensating for gain fluctuations of the high frequency power amplification means when switching to is generated, and the gain of the variable gain amplification means is controlled based on this compensation information and transmission power control information. It is a thing.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a wireless transmission device and a control method thereof according to the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 shows the overall configuration of the embodiment of the present invention.
2 and the configuration of the main part thereof is shown in FIG.

In FIG. 1, the antenna 11 for transmission and reception is connected to the antenna port 12a of the antenna common circuit 12 in order to support the frequency division duplex system.
The antenna sharing circuit 12 includes a transmission side port 12t and a reception side port 12r, and a band pass filter (not shown) having a predetermined characteristic is provided between the antenna port 12a and the transmission side port 12t and between the antenna port 12a. And the receiving-side port 12r.

The receiving side port 12 of the antenna sharing circuit 12
The high frequency signal from r is supplied to the mixing circuit 22 through the low noise high frequency amplification circuit 21 of the reception circuit 20. The local oscillation signal from the local oscillation circuit 23 is supplied to the mixing circuit 22, the high frequency signal from the low noise amplification circuit 21 is converted into an intermediate frequency signal, and the intermediate frequency amplification circuit 24.
Through the demodulation circuit 25 and the received power detection circuit 26.

The output of the received power detection circuit 26 is negatively fed back to the intermediate frequency amplification circuit 24 so that its gain is automatically controlled, and the output of the demodulation circuit 25 is supplied to the baseband signal processing circuit 31. , Predetermined signal processing is performed, and reception information such as a voice signal is reproduced. The reproduced reception information includes transmission power instruction information from the base station or the like, and this instruction information is used by the microcomputer 32.
Is taken into.

In the baseband signal processing circuit 31, the transmission information such as a voice signal is subjected to predetermined signal processing, and the output signal of the baseband signal processing circuit 31 becomes
The modulation circuit 41 is supplied to the modulation circuit 41 of the transmission circuit 40,
Is output to the mixing circuit 4 through the intermediate frequency amplification circuit 42.
3 is supplied.

The mixing circuit 43 includes a local oscillation circuit 23.
From the intermediate frequency amplifier circuit 4
The intermediate frequency signal from 2 is converted into a high frequency signal, and is supplied to the transmission side port 12t of the antenna sharing circuit 12 through the drive amplification circuit 44 and the high frequency power amplification circuit 45.

The gain of the intermediate frequency amplifier circuit 42 is controlled by the transmission power control signal from the transmission power control circuit 46. This transmission power control signal is generated based on the reception power detection information from the reception power detection circuit 26 and the transmission power instruction information from the microcomputer 32. The configuration as described above is the same as that of the already proposed wireless transmission device.

In the embodiment of FIG. 1, a bias control circuit 47 for performing bias control is provided for the high frequency power amplification circuit 45 of the transmission circuit 40, and gain compensation control is performed for the variable gain drive amplification circuit 44. A compensation control circuit 48 is provided. Then, a transmission power control signal from the transmission power control circuit 46 is supplied to each of the control circuits 47 and 48.

The high frequency power amplifier circuit 45 and the bias control circuit 47 are constructed as shown in FIG. Also,
The compensation control circuit 48 is, for example, a predetermined switching level of the transmission power and the high frequency power amplifier circuit 4 corresponding to each switching level.
It is configured to include a ROM table with gain variation amounts of 5.

As shown in FIG. 2, the high frequency power amplifier circuit 45 of this embodiment has a plurality of electric field effects divided into a plurality of groups 45a, 45b ... Transistors Qa1, Qa2, ...
QaL; Qb1, Qb2, ..., Qbm; ...; Qj1, Qj2, ...
, Qjn are included, and the sources of these field effect transistors Qa1 to Qjn are all grounded.

A high-frequency signal from the input terminal Ti receives the matching circuit 2 and a capacitor C connected in parallel to the output side thereof.
Each group 45a to 45 through a, Cb ...
It is commonly supplied to the gates of all field effect transistors Qa1 to Qjn of j.

The field effect transistors Qa1 to QaL;
The gates of Qb1 to Qbm; ..., Qj1 to Qjn are supplied to the gates of the bias control circuit 47 controlled by the transmission power control information.
Each group 4 through the resistors Ra, Rb, ..., Rj.
A required gate bias voltage is supplied to each of 5a, 45b, ..., 45j.

In the embodiment of FIG. 2, the first group 4
The gates of the field effect transistors Qa1 to QaL of 5a are
The gate bias voltage Vg-on for operating the field effect transistor is constantly supplied. Also, the field effect transistors Qb1 of the second to jth groups 45b, ..., 45j.
˜Qbm; ...; The gates of Qj1 to Qjn are connected to the gate bias voltage Vg-on or the field effect transistor which activates the field effect transistor through the changeover switches 47b, ..., 47j of the bias control circuit 47. The gate bias voltage Vg-off which is in a non-operating state is selectively supplied.

The drains of the field effect transistors Qa1 to Qjn of the groups 45a to 45j are all connected in common, and the power source V is supplied through the high frequency choke coil Lch.
dd is supplied, and field effect transistors Qa1 to Qa
The high frequency signal of each drain of jn goes through the matching circuit 3,
It is led to the output terminal To.

The numbers L, m, ..., N of the field effect transistors of each group 45a to 45j do not necessarily have to be equal. Further, the changeover switches 47b, ...
47j is, for example, a semiconductor switch, and can be integrated in the same manufacturing process as the field effect transistors Qa1 to Qjn as already proposed.

Next, the operation of the embodiment of the present invention will be described. In this embodiment, the transmission power control circuit 4
6, the transmission power control information is generated based on the transmission power instruction information from the base station or the like, and this control information is supplied to the bias control circuit 47 and the compensation control circuit 48, and the high frequency power amplification circuit 45 Bias control and compensation control of the drive amplifier circuit 44 are performed.

As a result of the bias control and the compensation control, the power control in the high frequency power amplifier circuit 45 is performed, and in the drive amplifier circuit 44, the compensation amount of the gain variation accompanying the power control in the high frequency power amplifier circuit 45 is compensated. , The gain control is performed, and the output level of the drive amplification circuit 44 changes.

When the transmission power instruction information from the base station or the like instructs the transmission at the maximum output of the high frequency power amplifier circuit 45, the bias control circuit 47 is generated by the transmission power control signal generated by the transmission power control circuit 46. All the changeover switches 47b to 47j are switched to the n side shown in the figure.

In this case, the gate bias voltage Vg-on is
The field effect transistors Qa1 to Qjn of all the groups 45a to 45j are supplied to the gates to activate all the field effect transistors Qa1 to Qjn, the output of the high frequency power amplifier circuit 45 is maximized, and the current consumption is also increased. It will be the maximum.

When the transmission power instruction information instructs the transmission at the minimum output of the high frequency power amplifier circuit 45, the transmission power control signal generated in the transmission power control circuit 46 causes all of the bias control circuits 47 to be transmitted. The changeover switches 47b to 47k are switched to the illustrated f side.

In this case, the gate bias voltage Vg-off
Are supplied to the gates of the field effect transistors Qb1 to Qbm of the second to jth groups 45b to 45j ... Qj1 to Qjn, and the field effect transistors Qb1 to Qbm;
The gate bias voltage Vg-on is supplied to the gates of the field effect transistors Qa1 to QaL of the first group 45a so that only the field effect transistors Qa1 to QaL are activated while Qj1 to Qjn are deactivated. The output of the high frequency power amplifier circuit 45 is minimized and the current consumption is also minimized.

When the transmission power instruction information instructs transmission at the intermediate output of the high frequency power amplifier circuit 45, bias control is performed according to the value of the intermediate output, for example, as shown in FIG. Changeover switch 47b of circuit 47
Is switched to the n side, the changeover switch 47j is changed to the f side, and the remaining changeover switches (not shown) are appropriately changed over to either the n side or the f side.

In this case, the gate bias voltage Vg-of
f is supplied to at least the gates of the field effect transistors Qj1 to Qjn of the j-th group 45j to deactivate the field effect transistors Qj1 to Qjn, and
The gate bias voltage Vg-on has field effect transistors Qa1 to QaL of the first and second groups 45a and 45b;
The field effect transistors Qa1 to QaL; Qb1 to Qbm are supplied to the gates of Qb1 to Qbm to operate, and the field effect transistors of the remaining group (not shown) operate or operate according to the value of the intermediate output. The output of the high-frequency power amplifier circuit 45 and the consumed current are both in the non-operating state, and have an appropriate value between the maximum value and the minimum value.

When the transmission power is switched in the high frequency power amplifier circuit 45 as described above, the compensation control circuit 48 switches each transmission power level of the high frequency power amplifier circuit 45 based on the ROM table as described above. Is set, and the drive output of the drive amplifier circuit 44 is controlled by adding or subtracting the gain change amount.

That is, in the case of reducing the transmission power, in the high frequency power amplifier circuit 45, as described above, the bias control circuit 47 reduces the number of groups in which the field effect transistors are in the operating state, and the high frequency power amplifier circuit is reduced. The gain of 45 decreases.

In this case, in the compensation control circuit 48,
A gain reduction amount of the high frequency power amplification circuit 45 is set based on the ROM table, and a control signal for increasing the gain of the drive amplification circuit 44 is generated by the gain reduction amount.

Further, in the case of increasing the transmission power, in the high frequency power amplifier circuit 45, the bias control circuit 47 increases the number of groups in which the field effect transistors are in the operating state as described above, and the high frequency power amplifier circuit is amplified. Circuit 45
Gain of. In this case, in the compensation control circuit 48, the gain increase amount of the high frequency power amplifier circuit 45 is set based on the ROM table, and only this gain increase amount is set.
A control signal that reduces the gain of the drive amplifier circuit 44 is generated.

Thus, the gain variation due to the power control in the high frequency power amplifier circuit 45 is compensated in the drive amplifier circuit 44.

[Other Embodiments] In the above embodiment, the drive amplifier circuit 44 immediately before the high frequency power amplifier circuit 45 is used.
In the above, the gain fluctuation due to the transmission power control of the high frequency power amplifier circuit 45 is compensated, but the gain fluctuation due to the transmission power control of the high frequency power amplifier circuit 45 is further compensated in the preceding intermediate frequency amplifier circuit 42. You may do it.

In the above embodiment, the field effect transistor is used as the active element of the high frequency power amplifier circuit 45, but a bipolar transistor may be used.

[0047]

As described above, according to the present invention, it is possible to switch the operating state of the active elements of the high frequency power amplifier circuit for each group to compensate for the gain fluctuation when controlling the transmission power.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of an embodiment of a wireless transmission device according to the present invention.

FIG. 2 is a diagram showing a configuration of a main part of an embodiment of the present invention.

FIG. 3 is a diagram for explaining an operation of an example of a previously proposed wireless transmission device.

FIG. 4 is a diagram for explaining the operation of an example of the previously proposed wireless transmission device.

[Explanation of symbols]

11 antenna, 12 antenna common circuit, 20 receiving circuit, 21 high-frequency amplifier circuit, 25 demodulation circuit, 26 ...
Received power detection circuit, 31 ... Baseband signal processing circuit,
32 ... Microcomputer, 40 ... Transmission circuit, 41 ...
Modulation circuit, 42 ... Intermediate frequency amplification circuit, 44 ... Drive amplification circuit, 45 ... High frequency power amplification circuit, 46 ... Transmission power control circuit, 47 ... Bias control circuit, 48 ... Compensation control circuit, Q
a1 to Qjn ... Field effect transistor

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H03G 5/16 H03G 5/16 B

Claims (4)

[Claims] 1. A high frequency power amplification means including a plurality of active elements divided into a plurality of groups, an information generation means for generating transmission power control information corresponding to a predetermined transmission power of the high frequency power amplification means, and this information. Group control means for switching the operating state of the active elements of the high frequency power amplification means for each group based on the transmission power control information from the generation means, and for supplying a predetermined high frequency signal to the high frequency power amplification means Variable gain amplifying means, including a compensation information generating means for compensating for a gain variation of the high frequency power amplifying means when switching the operating states of the active elements for each of the groups. A radio transmitting apparatus comprising: compensation control means for controlling the gain of the variable gain amplifying means based on information and the transmission power control information. 2. The radio transmitting apparatus according to claim 1, wherein the variable gain amplifying means is a drive amplifying means for directly supplying a high frequency signal to the high frequency power amplifying means. 3. The radio transmitting apparatus according to claim 1, wherein the variable gain amplifying means is an intermediate frequency amplifying means for indirectly supplying a high frequency signal to the high frequency power amplifying means. 4. A plurality of active elements of the high frequency power amplification means to which a predetermined high frequency signal is supplied from the variable gain amplification means are divided into a plurality of groups, and based on transmission power control information corresponding to a predetermined transmission power, A method of controlling a radio transmitter for switching the operating states of the active elements of the high-frequency power amplifying means for each group, wherein the high-frequency power amplifying means for switching the operating states of the active elements for each group. Generating compensation information for compensating the gain fluctuation of the variable gain amplifying means, and controlling the gain of the variable gain amplifying means based on the compensation information and the transmission power control information. .