JP2006262240A - Power amplification device and mobile phone terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make device configuration compact by decreasing the number of necessary components while adapting the device to a plurality of frequencies. <P>SOLUTION: The power amplification device is equipped with a switch circuit 103 which selects one of first and second input terminals corresponding to signals of first and second frequencies, an amplifier including amplifying elements (FETs 105 and 109) connected to output terminals of the switch circuit 103, first and second load circuits 111 and 112 connected to output terminals of the amplifier, and a second switch circuit 113 which switches a first state wherein at least one of the first and second load circuits is used and a second state wherein the other is used associatively with switching of the switch circuit 103 corresponding to the first frequency and second frequency. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a power amplifying device, and more particularly to a high frequency power amplifying device that can be used in a mobile phone terminal.

Currently, mobile phone services called third generation are becoming more and more popular. Radio frequencies are becoming tighter, and new frequencies are being allocated and reorganized. As a result, signals from multiple frequency bands can be transmitted from a single terminal. There is a need to send. On the other hand, mobile phone terminals are becoming more and more miniaturized, and it is difficult to mount a radio unit corresponding to a plurality of frequencies. In particular, the power amplifying device is difficult to be integrated with other circuits, and is a factor that presses down on the space. This downsizing is an important issue.
Y. Hasegawa, Y. Ogata, I. Nagasako, N. Iwata, M. Kanamori, T. Ito, "3.4V Operation Power Amplifier Multi-chip IC's for Digital Cellular Phone," IEEE GaAs IC Symposium Digest 1995, pp. 63 -66

  Many power amplifying devices aiming at miniaturization have been put into practical use both inside and outside. For example, as seen in non-patent literature, it can be said that the mainstream is a method of miniaturizing by using packaging technology using high-performance FETs. .

  However, when dealing with a plurality of frequencies by this method, it is necessary to prepare power amplifying devices for the frequencies, and there is a problem that space merit cannot be obtained.

  The present invention has been made in such a background, and an object of the present invention is to provide a power amplifying device capable of reducing the number of necessary components and downsizing the device configuration while supporting a plurality of frequencies, and the use thereof. Is to provide a mobile phone terminal.

  According to the present invention, the first and second input terminals corresponding to the signals of the first and second frequencies, the first switch circuit for selecting one of these input terminals, and the first switch An amplifier including an amplifying element connected to an output terminal of the circuit; first and second load circuits connected to the output terminal of the amplifier; and the first and second frequencies respectively corresponding to the first frequency and the second frequency And a second switch circuit that switches between a first state using at least one of the first and second load circuits and a second state using at least the other in conjunction with switching of one switch circuit. It is characterized by that.

  The load connected to the output terminal of the amplifier is connected to the first and second frequency signals by switching between the first and second states in order to uniquely satisfy the efficiency, distortion and output of the power amplifying device. While setting an appropriate load impedance for each, the circuit scale is reduced by sharing the amplifier for both frequencies.

  The amplifier can be composed of first and second common-source FETs. Further, by configuring the first and second switch circuits using FETs, the entire amplifying device including the switch circuit can be configured as a monolithic integrated circuit.

  A cellular phone terminal according to the present invention includes the power amplifying apparatus having the above-described configuration.

  The power amplifying device according to the present invention can deal with a plurality of frequencies by sharing an amplifier for a plurality of frequency bands and switching a load circuit. For example, it is possible to reduce the size of a mobile phone terminal.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows a configuration of a power amplifying apparatus 100 according to the first embodiment of the present invention. The power amplifying apparatus 100 includes first and second input terminals 101 and 102 corresponding to the first and second frequency signals S1 and S2, respectively, and two input terminals 103b and 103c connected to both terminals, respectively. A first two-input one-output switch circuit 103 having an output terminal 103a selectively connected to one of them. The output terminal of the switch circuit 103 is connected to the gate terminal of the first common-source FET 105 through the first matching circuit 104. The drain terminal of the first common-source FET 105 is connected to the gate terminal of the second common-source FET 109 via the second matching circuit 108. The drain terminal of the FET 109 is connected to one end of the first load circuit (ML) 111, the other end is branched into two branches, and the second load circuit (ML) 112 is connected to the first branch destination of the two branches. The first input terminal 113b of the second switch circuit 113 is connected to the second branch destination. The other end of the second load circuit 112 is connected to the second input terminal of the switch circuit 113. The output terminal of the switch circuit 113 is selectively connected to one of the first and second input terminals 113b and 113c, and constitutes an output terminal of the power amplifying apparatus 100. The drain terminals of the first and second FETs 105 and 109 are connected to a DC power source 119 (Vdd) via coils 106 and 107 (or a transmission line having a predetermined length), respectively.

  The switch circuits 103 and 113 are each controlled to be switched in conjunction with a switching signal 121 from the control unit 120. That is, when the signal S1 is selected by the switch circuit 103, the load circuit 111 (load impedance is ML11) and the load circuit 112 (load impedance is ML12) connected in series are selected. The load impedance at this time is ML11 + ML12. When the switch circuit 103 selects the signal S2, the load circuit 111 is selected alone. The load impedance at this time is ML11. For these two loads, the following two states are defined.

State A: input signal S1, load ML11 + ML12,
State B: input signal S2, load ML11

  These two states are the operation of the power amplifying device when the input signal is the first frequency, that is, when the signal S1 is selected, and when the input signal is the second frequency, that is, when the signal S2 is selected. The state is switched. For example, here, it is assumed that the first frequency is 815 MHz and the second frequency is 900 MHz. The first and second matching circuits 104 and 108 have a broadband characteristic over these bands. That is, the circuit can be shared for the first and second frequencies.

  On the other hand, the load connected to the drain terminal of the FET 109 needs to uniquely satisfy the efficiency, distortion, and output of the power amplifying device, and is set separately for each frequency. For this purpose, the load impedance is switched as described above.

  Note that switching control of the switch circuits 103 and 113 by the control unit 120 depends on (1) an instruction from the base station, (2) an instruction from the user, (3) an instruction from a terminal device using this power amplification device, and the like. Can be done.

  FIG. 2 shows a specific circuit configuration example of the load circuits 111 and 112 in FIG. In this example, the load circuit 111 includes coils 111a and 111b connected in series and a capacitor 111c connected between the connection point and the ground. On the other hand, the load circuit 112 includes capacitors 112a and 112b connected in series, and a coil 112c connected between the connection point and the ground. However, these load circuits are merely examples, and the present invention is not limited to these specific examples. The specific configuration of the load circuits 111 and 112 may vary depending on the first and second frequencies used and the required specifications.

  FIG. 3 shows a configuration of the power amplifying device 110 according to the second embodiment of the present invention. In this figure, the same components as those shown in the first embodiment (FIG. 1) are denoted by the same reference numerals, and redundant description is omitted. The second embodiment differs from the first embodiment in the configuration in the configuration of the load. That is, the drain terminal of the second FET 109 is connected to the input terminal 131a of the switch circuit 131 having one input and two outputs. One output terminal 131 c of the switch circuit 131 is connected to the first load circuit (ML) 132, and the other output terminal 131 b is connected to the second load circuit (ML) 133. The output of the first load circuit (ML) 132 is connected to the output end 134 of the power amplification device 110, and the second load circuit (ML) 133 is connected to the output end 135 of the power amplification device 110. The switch circuit 131 is switched in conjunction with the switch circuit 103 by a switching signal 121 of the control unit 120. That is, when the signal S1 is selected by the switch circuit 103, the load circuit 132 (load impedance is ML21) is selected. When the signal S2 is selected by the switch circuit 103, the load circuit 133 (load impedance is ML22) is selected. For these two loads, the following two states are defined.

State A: input signal S1, load ML21,
State B: input signal S2, load ML22

  Similar to the first embodiment, these two states are the case where the input signal is the first frequency, that is, the signal S1 is selected, and the case where the input signal is the second frequency, that is, the signal S2 is selected. Depending on the case, the operating state of the power amplifier is switched.

  FIG. 4 shows a specific circuit configuration example of the load circuits 131 and 133. In this example, each load circuit includes coils 131a and 131b connected in series, a capacitor 131c connected between a connection point between the coils 131a and 131b, and a capacitor 131d connected to the output terminal 134. . However, the specific configuration of the load circuits 111 and 112 may vary depending on the first and second frequencies used and the required specifications. These load circuits are merely examples, and the present invention is not limited to these specific examples.

  The number of output terminals differs between the configuration of FIG. 3 and the configuration of FIG. The output terminal is determined by the characteristics of the antenna duplexer connected to the output side of the power amplifier. That is, when the antenna duplexer has a wide band that can handle the first and first frequencies, the configuration of FIG. 1 that can save one output terminal is appropriate, but two antenna duplexers are prepared. If so, the configuration of FIG. 3 is appropriate.

  FIG. 5 shows a schematic circuit configuration example of the switch circuit 113 of FIG. In this example, the channel between the source and drain terminals of the FET 113f and the FET 113g is selected by applying a control signal (for example, the switching signal 121 and its inverted signal) from the control terminals 113d and 113e to the gate terminal via a resistor. To conduct automatically. The same applies to other switch circuits. By configuring the switch circuit using FETs in this way, the entire amplifying device of the present invention including the switch circuit can be formed into a monolithic integrated circuit. This contributes to the downsizing of the apparatus together with the reduction in the number of parts.

  FIG. 6 is a block diagram showing an outline of the hardware configuration of the mobile phone terminal 500 that can use the power amplifier of the present invention. The cellular phone terminal 500 includes an antenna 501, an antenna duplexer 502, a transmission / reception processing unit 503, a modulation / demodulation processing unit 505, a data processing unit 507, a voice input / output processing unit 509, a speaker 510, and a microphone as elements unique to the cellular phone. 512. The cellular phone terminal 500 also functions as a control unit 525 including a CPU, a ROM, and the like for controlling these elements, a memory 527 used as a work area and a temporary storage area for data by the control unit 525, and a user interface. A display unit 520 and an operation unit 523 corresponding to the various operation keys are provided. The power amplifying apparatus of the present invention is located in the transmission / reception processing unit 503.

  The preferred embodiments of the present invention have been described above, but various modifications and changes other than those mentioned above can be made. For example, the switching of the load circuit is not limited to the example of FIGS. 1 and 3, and the first state using at least one of the first and second load circuits and the second state using at least the other are switched. Anything is acceptable.

FIG. 1 is a circuit block diagram showing a configuration of a power amplifying device according to a first embodiment of the present invention. FIG. 2 is a circuit diagram illustrating a specific configuration example of a load circuit illustrated in FIG. 1. It is a circuit block diagram which shows the structure of the power amplification apparatus in the 2nd Embodiment of this invention. FIG. 4 is a circuit diagram illustrating a specific configuration example of a load circuit illustrated in FIG. 3. FIG. 2 is a circuit diagram illustrating a schematic circuit configuration example of a switch circuit 113 in FIG. 1. It is a block diagram which shows the outline of the hardware constitutions of the mobile telephone terminal which can use the power amplifier of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Power amplifier 101, 102 ... Input terminal, 103 ... Switch circuit, 104 ... Matching circuit, 105 ... Common source FET, 106, 107 ... Coil, 108 ... Matching circuit, 109 ... Common source FET, 110 ... Power amplification Device, 111, 112 ... load circuit, 113 ... switch circuit, 119 ... DC power supply, 120 ... control unit, 121 ... switching signal, 131 ... switch circuit, 132, 133 ... load circuit, 134, 135 ... output terminal, 500 ... Mobile phone terminal

Claims (9)

First and second input terminals corresponding to signals of first and second frequencies;
A first switch circuit for selecting one of these input terminals;
An amplifier including an amplifying element connected to the output terminal of the first switch circuit;
First and second load circuits respectively connected to the output terminal of the amplifier and corresponding to the first frequency and the second frequency;
A second switch circuit that switches between a first state using at least one of the first and second load circuits and a second state using at least the other in conjunction with switching of the first switch circuit; A power amplifying device comprising:   2. The first state uses the first load circuit alone, and the second state uses a circuit combining the first and second load circuits. Power amplifier.   The second switch circuit is a two-input one-output switch circuit, and receives the output signal of the amplifier by a circuit in which the first load circuit and the second load circuit are connected in series. The connection point and the output terminal of the second load circuit are connected to both input terminals of the second switch circuit, respectively, and the output terminal of the second switch circuit is used as the output terminal of the power amplifier. The power amplification device according to claim 2.   2. The power amplifying apparatus according to claim 1, wherein the first state uses the first load circuit alone, and the second state uses the second load circuit alone.   As the second switch circuit, a 1-input 2-output switch circuit that receives the output signal of the amplifier is provided in front of the first and second load circuits, and the first and second load circuits are provided by the switch circuit. 5. The power amplifying apparatus according to claim 4, wherein the output signal is selectively supplied to the first and second load circuits, and the output terminals of the first and second load circuits are used as output terminals of the power amplifying apparatus.   The power amplifier according to any one of claims 1 to 5, wherein the amplifier includes first and second common-source FETs.   The amplifier includes a first matching circuit connected between the first switch circuit and a gate terminal of the first source grounded FET, a drain terminal of the first source grounded FET, and the second source. A second matching circuit connected between the gate terminal of the common-source FET and a coil or transmission line connected between the drain terminal of the first and second FETs and a power supply; 7. The power amplifying apparatus according to claim 6, wherein the first and second matching circuits have broadband characteristics corresponding to both the first and second frequencies.   The power amplifying apparatus according to claim 6, wherein the first and second switch circuits are configured using FETs. A mobile phone terminal equipped with a power amplification device,
The power amplification device includes:
First and second input terminals corresponding to signals of first and second frequencies;
A first switch circuit for selecting one of these input terminals;
An amplifier including an amplifying element connected to the output terminal of the first switch circuit;
First and second load circuits connected to the output terminal of the amplifier;
In conjunction with switching of the first switch circuit corresponding to the first frequency and the second frequency, respectively, the first state and at least the other using at least one of the first and second load circuits are A mobile phone terminal comprising: a second switch circuit that switches a second state to be used.

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