JP4521806B2 - Power amplification device and transmission device - Google Patents

Description

  The present invention relates to a power amplification device and a transmission device used in a mobile communication terminal device such as a mobile phone device.

  A mobile communication terminal device (hereinafter referred to as a terminal) has a built-in power amplifying device for generating transmission power to the base station, and the power consumption of this power amplifying device is dominant during a call, In order to extend time (that is, to extend battery life), it is important to reduce the power consumption of the power amplifying apparatus.

  Hereinafter, a conventional technique for reducing the power consumption of the power amplifying apparatus will be described.

  In a Code Division Multiple Access (CDMA) terminal, power control for a power amplifying apparatus is finely performed. This is to avoid power fluctuations caused by fading caused by the terminal moving around and the state of radio wave propagation changing, and accordingly the received electric field strength fluctuating with time. Also, since many terminals communicate using the same frequency, if the power of radio waves from a specific terminal is stronger than the power from other terminals, the signal of the radio wave with the lower power is masked and received. This is to avoid being unable to do so. Actually, the transmission power of each terminal is controlled so that the power of radio waves from each terminal received at the base station becomes equal.

  By the way, with respect to the cellular phone device incorporating the power amplification device, the US TIA standard IS-95 and ARIB STDT-53 stipulate that the maximum transmission power is 200 mW. As a result of the test, it is confirmed that the operating condition of the output is about 10 dB lower although it is a power amplifying apparatus having a transmission power of 200 mW.

  The power amplifying device of the cellular phone device emphasizes linearity in order to amplify the QPSK modulated wave, but the amplifying device that emphasizes linearity has a bias of about 100 mA even if no signal is input. Necessary. That is, the idle current increases. For example, as the power amplifying device for the mobile phone device, a two-stage combination of two amplifiers is used. For example, the first-stage amplifier does not cover 15 dBm, and the second-stage amplifier covers 25 dBm. Since power for the first stage amplifier is sufficient in actual use, an idle current of 100 mA is wasted in situations where one stage of amplifier is unnecessary.

  Conventionally, a configuration as shown in FIG. 1 has been used in order to prevent unnecessary power consumption in the built-in power amplifying device to increase power efficiency and extend the actual call time (see Patent Document 1).

  In the configuration of FIG. 1, the power amplifying device includes a first-stage amplifier 11 and a second-stage amplifier 12, and has a signal input end 17 and an output end 18. When the power transmitted to the base station is equal to or lower than the power that can be provided by the first-stage amplifier 11, the contacts of the selector switch 13 and the selector switch 14 are set to the b side (between the terminals bc) and the amplifier 12 is connected. Is cut off, and the power supply voltage VDD is cut off from being supplied to the amplifier 12 at the second stage by turning off the VDD switch 15, thereby reducing useless idle current flowing through the amplifier 12. When the power transmitted to the base station cannot be covered by the first-stage amplifier 11, the contacts of the changeover switch 13 and changeover switch 14 are set to the a side (connection between terminals ac) and the VDD switch 15 And the amplifier 12 is operated.

  In the case of a full-duplex transceiver such as the CDMA system, since both the transmission unit and the reception unit operate at the same time, two types of interference may occur. The first disturbance is transmission band power that enters the reception unit, and the second disturbance is noise that leaks reception band noise generated by the transmission unit and enters the reception unit. The second disturbance deteriorates reception sensitivity. Both disturbances can be mitigated by using a duplexer. The pass loss in the transmission band of the duplexer increases as the attenuation in the reception band increases.

  Since the rated output power at the antenna end of the terminal needs to be within the standard defined by the type of terminal, if the transmission loss of the duplexer transmission band increases, the output power required for the power amplifying device also increases. Therefore, a lot of current is required. In other words, in order to reduce the power consumption of the power amplifying device, it is necessary to reduce the attenuation in the reception band when the antenna end is viewed from the transmission circuit end of the duplexer, and to reduce the pass loss of the transmission band of the duplexer.

  FIG. 2 is a configuration example of a full-duplex transceiver. This full-duplex transceiver includes an antenna 1, a duplexer 4, a reception circuit 2, and a transmission circuit 3.

  FIG. 3 is a configuration example of the transmission circuit illustrated in FIG. 2, and shows a conventional example that realizes low power consumption of the power amplification device. In FIG. 3, the transmission circuit includes IQ signal input terminals 37 and 38, a quadrature modulator 35, a transmission bandpass filter 34, and a power amplification device 30, and the output of the power amplification device 30 is connected to the antenna 1 through the duplexer 4. Has been. Here, the power amplifying apparatus 30 includes a first-stage amplifier 33, a final-stage amplifier 31, and a band-pass filter 32 disposed between them for blocking the reception band, and attenuates reception band noise generated at the output of the final-stage amplifier 31. By doing so, the transmission pass loss of the duplexer 4 can be reduced, so that the output power of the power amplifying device 30 is reduced to realize low power consumption (Patent Document 2).

  The duplexer 4 is a three-terminal (4a, 4b, 4c) passive element composed of a pair of bandpass filters 40, 41 and phase shift circuits 42, 49, as shown in FIG.

  The duplexer is composed of a BPF 40 that uses the reception band as a pass band and attenuates the transmission band, a BPF 41 that uses the transmission band as a pass band and attenuates the reception band, and phase shift circuits 42 and 49 placed between the two BPFs and the antenna connection terminal 4a. Is done. A receiving circuit is connected to the terminal 4b, and a transmitting circuit is connected to the terminal 4c. Here, an example in which a transmission line is used as the phase shift circuits 42 and 49 is shown.

FIG. 5 shows a configuration that can be considered as a combination of FIG. 1 and FIG. 3 in order to realize lower power consumption of the power amplifier. When the transmission power is low, the switch 13 and the switch 14 are switched to a state opposite to the state shown in the figure, so that the transmission signal does not pass through the final amplifier 31 and is not shown here (similar to FIG. 1). By cutting off the power supply to the stage amplifier 31, current consumption can be reduced. Although the band pass filter 32 is arranged between the switch 13 and the final stage amplifier 31 in FIG. 5, it may be arranged between the switch 13 and the first stage amplifier 33. The matching circuit 55 and the matching circuit 56 are circuits for matching the input and output of the final stage amplifier 31, and the matching circuit 53 and the matching circuit 54 are for matching the input and output of the first stage amplifier 33. The circuit is shown.
JP 2001-217661 A JP 2002-185262 A

  Currently, dual-band mobile phone terminals that operate in a plurality of frequency bands (bands) have been put into practical use as mobile communication terminals. For example, a CDMA dual band mobile phone terminal using an 800 MHz band and a 900 MHz band has been put into practical use. A conventional dual-band mobile phone terminal uses a configuration as shown in FIG.

  On the other hand, in recent years, a direct conversion reception system (DCR) has been put into practical use, and a receiving circuit and a transmitting circuit used in a plurality of frequency bands can be configured by only one system each. As a result, the dual-band mobile phone terminal having the configuration shown in FIG. 6 can be realized with the configuration shown in FIG. 7. By reducing the number of receiving circuits and transmitting circuits, the size and price of the terminal can be reduced. It has become possible. Further, when the conventional technology for realizing the low power consumption of the power amplifying device is applied to such a dual-band mobile phone terminal, the power amplifying devices 8 and 8 ′ of FIG. The devices 30 and 30 ′ are replaced.

  However, in the configuration examples of FIG. 7 and FIG. 8, although the receiving circuit and the transmitting circuit can be partially reduced, a plurality of power amplifying devices used in each frequency band are used, and this power amplifying device is large and expensive. There was a problem that the shape of the dual-band mobile phone terminal was large and the price was high. This is because the current consumption needs to be reduced as much as possible by configuring the matching circuit 56 and the like in the power amplifying apparatus shown in FIG.

  The present invention has been made in such a background, and an object thereof is to reduce the power consumption while realizing a small and low-priced communication terminal by using a single power amplifying device for a dual band system. An object of the present invention is to provide a power amplification device that can be realized and a transmission device using the same.

  A power amplifying apparatus according to the present invention is a power amplifying apparatus used in first and second frequency bands, and the first and second amplifiers are connected in series with the first and second amplifiers. First switching means for selectively configuring a first path to be performed and a second path including only the first amplifier, and supplying power to the second amplifier when the second path is selected. A power shut-off means for shutting off, first and second output terminals corresponding to the first and second frequency bands, respectively, and the second amplifier according to a frequency band used when the first path is selected. An output is selectively output to one of the first and second output terminals, and an output of the first amplifier is selected according to a frequency band used when the second path is selected. Switch to selectively output to one of the output terminals. Characterized in that a second switching means for obtaining.

  The first switching means selectively configures a first path connecting the first and second amplifiers in series and a second path including only the first amplifier. By switching between the first path and the second path, whether to use both the first and second amplifiers or only the first amplifier is switched, so that the output power is switched between high and low. That is, the first switching means selects the first path when high output power is required, and selects the second path when low output power is required, and the second switching means. The switching means and the power cutoff means operate in conjunction with the switching of the path.

  When the second path is selected, that is, when only the first amplifier is used, power supply to the second amplifier is cut off, so that useless power consumption is reduced.

  One of the first and second frequency bands can be selected for both high output power and low output power. This selection is performed by the second switching means. The second switching means realizes path switching and use frequency band switching with a single switching means (for example, a DPDT type switch), thereby reducing the passage loss.

  Furthermore, since the signals in the first and second frequency bands can be switched and output by the second switching means, the matching circuit for the second amplifier can be optimized for each frequency band.

  When the power amplification device is used as a transmission device, it is preferable that a reception band rejection filter that attenuates both reception bands of the first and second frequency bands is inserted at least in the first path. . As a result, the reception band noise generated at the amplifier output is attenuated to eliminate the need for reception band attenuation at the subsequent duplexer, thereby reducing the transmission pass loss.As a result, the output power of the power amplification device is reduced, Low power consumption can be achieved.

  In place of the reception band rejection filter, first and second filters that attenuate the reception bands of the first and second frequency bands may be provided. In this case, the first switching means switches the first and second filters together with the path switching.

  The power amplifying device selectively selects first and second input terminals corresponding to the first and second frequency bands, and the first and second input terminals, respectively, as input terminals of the first amplifier. And a third switching means connected to. In particular, when the power amplifying apparatus is modularized, the third switching means can be included in the module.

  The transmission device according to the present invention includes the power amplification device described above, and selects the first path if the requested transmission power is equal to or greater than a predetermined value, and if the requested transmission power is less than the predetermined value, the second Control means is provided for selecting a path and operating the second switching means and the power shut-off means in conjunction with the switching of the path.

  According to the present invention, by appropriately using the first and second switching means, the power amplifying apparatus used in the first and second frequency bands switches between low output power and high output power. The first and second amplifiers can be shared by the first and second frequency bands, and the power amplifying device, and hence the transmitting device and terminal device using this can be reduced in size and price. Further, by using the power shut-off means, when the second amplifier is not used according to the required output power, the power supply can be cut off to reduce the power consumption.

  When reception frequency bands of the first and second frequency bands are close to each other, a reception band rejection filter is disposed between the first and second amplifiers to reduce reception band noise generated at the amplifier output. Attenuation reduces the transmission pass loss of the subsequent duplexer, and as a result, the output power of the power amplifying device can be reduced and the power consumption can be reduced.

  Hereinafter, preferred embodiments of the present invention will be described in detail.

  FIG. 9 is a circuit block diagram of the first embodiment of the power amplifier according to the present invention. In this embodiment, a single transmission module 50 has a first stage amplifier 33 (first amplifier) and a last stage amplifier 31 (second amplifier), and both amplifiers are in the first and second frequency bands. In addition, the number of amplifiers to be used is switched by the switch 13 (first switching means) according to the output power (output power) to reduce the power consumption at the time of low output.

For this purpose, a DPDT type switch 14 ( second switching means) is placed on the output side of the final amplifier 31, and the path switching by the output power and the path switching by the used frequency band are performed by this switch 14, thereby switching the conventional switching. The power amplifier can achieve both low power consumption and dual-band compatibility without increasing the passage loss compared to the configuration of the power amplifier (FIG. 1).

  More specifically, the input terminal 51 common to both frequency bands is connected to the input terminal of the first stage amplifier 33 via the matching circuit 53. The output terminal of the first stage amplifier 33 is connected to the input terminal a of the switch 13 via the matching circuit 54. The output terminal b of the switch 13 is connected to the input terminal of the band rejection filter 39 externally attached to the communication module 50, and the output terminal of the band rejection filter 39 is connected to the input terminal of the final stage amplifier 31 via the matching circuit 55. . The output terminal of the final amplifier 31 is connected to the terminal a of the DPDT switch 14. The terminal d of the switch 14 is connected to the output terminal 52 of the first frequency band via the matching circuit 56. The output terminal c of the switch 13 is connected to the terminal c of the DPDT switch 14, and the terminal b is connected to the output terminal 52 'of the second frequency band via the matching circuit 56'. The power supply voltage terminal 16 (VDD) constantly supplies power to the final amplifier 31, whereas the final amplifier 31 is selectively supplied to the final amplifier 31 via the switch 15 (power cutoff means) (only at high output power). Supply power.

  The embodiment of FIG. 9 shows a case where there is a single filter (reception band rejection filter 39) for attenuating reception band noise even in the case of dual band support. For example, as shown in FIG. 13, terminal transmission which is one of CDMA use bands for Japan: 915 to 925 MHz, terminal reception: 860 to 870 MHz, terminal transmission which is a use band of CDMA for the United States: 824 to 849 MHz, terminals Reception: In a dual-band mobile phone terminal of 869 to 894 MHz, both reception frequency bands are close to each other, and even if both are combined, the filter for attenuating both reception bands is a single reception band blocking. This can be realized with a filter.

  In FIG. 9, when the first frequency band is used, output power is supplied from the output terminal 52 via the matching circuit 56, and when using the second frequency band, the output is output via the matching circuit 56 ′. Output power is supplied from a terminal 52 '.

  The DPDT switch 14 has a first state in which the terminal a-d is ON, the terminal bc is ON, the terminals a-b are OFF, and the terminals cd are OFF, and the terminal a- There are two states, a second state in which the distance between d and the terminals bc is OFF and the terminals a and b are simultaneously ON and the terminals cd and ON are ON. One of the two states is selected according to the path switching by the used frequency band. The switch 13 is set according to path switching by output power. That is, the terminals a and b are turned on at high output power, and the terminals a and c are turned on at low output power. The states of these two switches 13 and 14 are collectively shown as follows.

  Although not shown, the transmission device (or terminal) includes a control unit (control means) that controls these switches according to whether the requested transmission power is greater than or less than a predetermined value.

  Although FIG. 9 shows that the reception band rejection filter 39 is disposed outside the transmission module, a high-reliability filter such as a thin film bulk acoustic resonance (FBAR) filter is used in the transmission module 50. It can also be built in.

  FIG. 10 is a circuit block diagram of a second embodiment of the power amplifying device according to the present invention. The same elements as those shown in FIG. 9 are denoted by the same reference numerals. The description which overlaps with the said embodiment is avoided and only a different part is demonstrated.

  This embodiment is different from the first embodiment in that a switch 13 that performs path switching based on output power is provided at the subsequent stage of the reception band rejection filter 39. In the example of FIG. 9, since the signal does not pass through the reception band rejection filter 39 in the low output power mode, the reception band noise almost determined by the gain of the first-stage amplifier 33 and NF (Noise Figure) is not sufficiently low. There may be cases. In such a case, the switch 13 can be placed after the reception band rejection filter 39 so that the signal passes through the reception band rejection filter 39 even in the low output power mode.

  However, since it is usually necessary to guarantee a certain output power even in the low output power mode, in the case of FIG. 10, the passing loss of the output of the power amplifying device in the low output power mode increases, and the first stage amplifier It is necessary to examine whether the output power is sufficient. As described above, either of the configurations shown in FIGS. 9 and 10 is selected by comparing the performance of the amplifier with the required reception band noise and the output power in the low output power mode.

  FIG. 11 is a circuit block diagram of a third embodiment of the power amplifying device according to the present invention. The same elements as those shown in FIG. 9 are denoted by the same reference numerals. The description which overlaps with the said embodiment is avoided and only a different part is demonstrated.

  In correspondence with a general dual band without the restriction as described above with reference to FIG. 13, two filters for blocking the reception band for attenuating the reception band noise are required. Therefore, the switch 13 is changed to an SP3T (Single Pole 3 Throw) type switch 13 ′, and the band pass filters 32 and 32 ′ are switched according to the used frequency band. If the bandpass filter 32 is a reception band rejection filter corresponding to the first frequency band and the bandpass filter 32 ′ is a reception band rejection filter corresponding to the second frequency band, the states of the switch 14 and the switch 13 ′ are as follows. It becomes like this.

  FIG. 12 is a circuit block diagram of a fourth embodiment of the power amplifier according to the present invention. The same elements as those shown in FIG. 9 are denoted by the same reference numerals. The description which overlaps with the said embodiment is avoided and only a different part is demonstrated.

  Usually, in the transmission circuit, as shown in FIG. 3, a transmission band pass filter 34 is used to attenuate noise and spurious outside the pass band. In the dual band correspondence, as shown in FIG. 8, since this filter becomes two filters 34 and 34 ', a switch 19 for switching between them is necessary. However, this switch 19 is incorporated in a communication module and integrated. Since the switch 19 is built in, the input matching circuit (53 and 53 ') of the first stage amplifier can be separated for each frequency band used, so that it is possible to design to optimize gain, reception band noise, etc. for each frequency band used. There is an advantage to become.

  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, although the switch 15 is illustrated as a mechanical switch, it may be an electronic switch using a switching element such as a transistor (the same applies to other switches).

It is a figure which shows the structure of the conventional power amplifier. It is a figure which shows the structural example of the conventional full-duplex transceiver. FIG. 3 is a diagram illustrating a configuration example of a transmission circuit illustrated in FIG. 2. It is a figure which shows the structural example of a duplexer. It is a figure which shows the structure of the power amplifier considered as a combination of FIG. 1 and FIG. It is a figure which shows the structural example of the conventional dual band mobile telephone terminal. It is a figure which shows the structural example of the dual band portable telephone terminal which reduced the receiving circuit and transmission circuit of FIG. It is a figure which shows the structural example of the transmission part of the conventional dual band portable telephone terminal in which power consumption was reduced. 1 is a circuit block diagram of a first embodiment of a power amplification device according to the present invention; FIG. 3 is a circuit block diagram of a second embodiment of a power amplifying device according to the present invention. It is a circuit block diagram of 3rd Embodiment of the power amplifier by this invention. It is a circuit block diagram of 4th Embodiment of the power amplifier by this invention. It is explanatory drawing of the example of the dual band which the receiving frequency band adjoined.

Explanation of symbols

4, 4 '... duplexer, 8, 8' ... power amplifier, 14 ... switch, 15 ... switch, 16 ... power supply voltage terminal, 30, 30 '... power amplifier, 31 ... final stage amplifier, 32, 32' ... Band pass filter, 33 ... First stage amplifier, 34, 34 '... Transmission band pass filter, 35 ... Quadrature modulator, 37 ... Signal input terminal, 39 ... Reception band rejection filter, 40 ... Band pass filter, 42 ... Phase shift circuit, DESCRIPTION OF SYMBOLS 50 ... Transmission module, 51, 51 '... Input terminal, 52, 52' ... Output terminal, 53 ... Matching circuit, 54 ... Matching circuit, 55 ... Matching circuit, 56, 56 '... Matching circuit

Claims (14)

A power amplifying device used for first and second frequency bands,
A first amplifier and a second amplifier;
First switching means for selectively configuring a first path connecting the first and second amplifiers in series and a second path including only the first amplifier;
A power shut-off means for shutting off the power supply to the second amplifier when the second path is selected;
First and second output terminals corresponding respectively to the first and second frequency bands;
A first matching circuit corresponding to the first frequency band disposed before the first output terminal;
A second matching circuit corresponding to the second frequency band disposed in front of the second output terminal;
A third matching circuit connected between the first amplifier and the first switching means;
When the first path is selected, the output of the second amplifier is selectively output to one of the first and second output terminals according to a frequency band used, and is used when the second path is selected. Second switching means for switching to selectively output the output of the first amplifier to one of the first and second output terminals according to a frequency band,
When high output power is required in the first frequency band, the first switching means selects the first path and the second switching means outputs the output of the second amplifier to the first frequency band. When the first output terminal is connected to the first output terminal via the matching circuit and low output power is required in the first frequency band, the first switching unit selects the second path and The output of the first amplifier is connected to the first output terminal via the first matching circuit by two switching means,
When high output power is required in the second frequency band, the first switching means selects the first path and the second switching means outputs the output of the second amplifier to the second frequency band. When the second output terminal is connected to the second output terminal via the matching circuit and low output power is required in the second frequency band, the first switching means selects the second path and the second An output of the first amplifier is connected to the second output terminal via the second matching circuit by two switching means.   The first switching means selects the first path when high output power is required, and selects the second path when low output power is required, and the second switching means. The power amplifying apparatus according to claim 1, wherein the means and the power shut-off means operate in conjunction with the switching of the path.   The power amplifying apparatus is used as a transmitting apparatus, and a reception band rejection filter for attenuating reception bands of both the first and second frequency bands is inserted at least in the first path. The power amplification device according to claim 1 or 2.   Instead of the reception band rejection filter, the first and second filters for attenuating the reception bands of the first and second frequency bands, respectively, the first switching means together with the switching of the path The power amplifying apparatus according to claim 3, wherein the first and second filters are switched.   A first input terminal corresponding to the first frequency band and a second input terminal corresponding to the second frequency band; and a third input terminal selectively connecting the first input terminal and the second input terminal to an input terminal of the first amplifier. The power amplifying apparatus according to claim 1, further comprising a switching unit. A power amplifying device used for first and second frequency bands,
A first switch having an input terminal a and output terminals b, c, selectively connecting the input terminal a to one of the output terminals b, c;
Whether input terminals a and c and output terminals b and d are connected, and terminals a-d and terminals bc are connected simultaneously or terminals a-b and terminals cd are connected simultaneously A second switch of DPDT (Dual Pole Dual Throw) type to selectively switch;
A power amplifier comprising a first amplifier and a second amplifier for receiving an input signal;
First and second output terminals corresponding respectively to the first and second frequency bands;
A first matching circuit corresponding to the first frequency band disposed before the first output terminal;
A second matching circuit corresponding to the second frequency band disposed in front of the second output terminal;
A third matching circuit connected between the first amplifier and the first switching means;
Power cutoff means for shutting off the power supply to the second amplifier when the input terminal a of the first switch is connected to the output terminal c;
The output of the first amplifier is input to the input terminal a of the first switch, the signal output from the output terminal b of the first switch is input to the second amplifier, and the first switch The output terminal c of the second switch is connected to the input terminal c of the second switch, the output of the second amplifier is input to the input terminal a of the second switch, and output from the output terminal d of the second switch. Is output to the first output terminal via the first matching circuit, and the signal output from the output terminal b of the second switch is the second output via the second matching circuit. Output to the output terminal of
When the output power required in the first frequency band is greater than or equal to a predetermined value, the input terminal a of the first switch is connected to the output terminal b and between the terminals ad of the second switch. Is connected,
When the output power required in the first frequency band is less than a predetermined value, the input terminal a of the first switch is connected to the output terminal c and between the terminals cd of the second switch. Is connected,
When the output power required in the second frequency band is greater than or equal to a predetermined value, the input terminal a of the first switch is connected to the output terminal b and between the terminals a and b of the second switch. Is connected,
When the output power required in the second frequency band is less than a predetermined value, the input terminal a of the first switch is connected to the output terminal c and the distance between the terminals c and b of the second switch. The power amplifying apparatus, wherein the first switch and the second switch are controlled so as to be connected.   A reception band rejection filter for attenuating both reception bands of the first and second frequency bands is inserted between the output terminal b of the first switch and the input terminal of the second amplifier. The power amplification device according to claim 6.   In place of the reception band rejection filter, first and second filters that attenuate the reception bands of the first and second frequency bands are provided, and the first switch has another output terminal c. The power amplifying apparatus according to claim 7, wherein the first and second filters are switched by switching output terminals b and c.   9. The power amplifying apparatus according to claim 7, wherein the filter is disposed in front of the first switch.   A first input terminal corresponding to the first frequency band and a second input terminal corresponding to the second frequency band; and a third input terminal selectively connecting the first input terminal and the second input terminal to an input terminal of the first amplifier. The power amplification device according to claim 6, further comprising a switch. A transmission device used for first and second frequency bands,
A first amplifier and a second amplifier;
First switching means for selectively configuring a first path connecting the first and second amplifiers in series and a second path including only the first amplifier;
A power shut-off means for shutting off power supply to the second amplifier when the second path is selected;
First and second output terminals corresponding respectively to the first and second frequency bands;
A first matching circuit corresponding to the first frequency band disposed in front of the first output terminal;
A second matching circuit corresponding to the second frequency band disposed in front of the second output terminal;
A third matching circuit connected between the first amplifier and the first switching means;
The output of the second amplifier is selectively output to the first and second output terminals according to the frequency band used when the first path is selected, and the frequency band used when the second path is selected. And a second switching means for switching to selectively output the output of the first amplifier to the first and second output terminals according to
When the transmission power requested in the first frequency band is equal to or greater than a predetermined value, the first switching unit selects the first path and the second switching unit outputs the second amplifier. Is connected to the first output terminal via the first matching circuit, and when the transmission power required in the first frequency band is less than a predetermined value, the second switching means And the output of the first amplifier is connected to the first output terminal via the first matching circuit by the second switching means, and requested in the second frequency band. When the transmission power is greater than or equal to a predetermined value, the first switching unit selects the first path, and the second switching unit outputs the output of the second amplifier via the second matching circuit. A second frequency connected to the second output terminal; When the transmission power requested in the area is less than a predetermined value, the second switching means selects the second path and the second switching means outputs the output of the first amplifier to the second Control means connected to the second output terminal via a matching circuit, and operating the second switching means and the power shut-off means in conjunction with the switching of the path;
A transmission device comprising:   12. The transmission apparatus according to claim 11, wherein a reception band rejection filter for attenuating both reception bands of the first and second frequency bands is inserted in at least the first path.   Instead of the reception band rejection filter, the first and second filters for attenuating the reception bands of the first and second frequency bands, respectively, the first switching means together with the switching of the path The transmission apparatus according to claim 12, wherein switching between the first filter and the second filter is performed.   A first input terminal corresponding to the first frequency band and a second input terminal corresponding to the second frequency band; and a third input terminal selectively connecting the first input terminal and the second input terminal to an input terminal of the first amplifier. 12. The transmission apparatus according to claim 11, further comprising switching means.

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