JP2013038560A - High frequency power amplification device, and electronic apparatus with communication function mounted with the high frequency power amplification device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high frequency power amplification device that reconciles a wide band and high efficiency, and an electronic apparatus with a communication function mounted therewith.SOLUTION: The high frequency power amplification device includes: an impedance converter circuit (fixed matching circuit) for, downstream of an amplifier, converting an output impedance of the amplifier to an impedance higher than the former impedance; and a variable impedance circuit (variable matching circuit) for, in response to a signal of the impedance of the impedance converter circuit, controlling a load impedance to match a load. The electronic apparatus with a communication function is mounted with the high frequency power amplification device.

Description

  The present invention relates to, for example, a multiband power amplifying apparatus that can handle 700 MHz to 2.0 GHz, amplifies an input signal input to one input terminal, and outputs the amplified signal to one or more (multiple) output terminals. The present invention relates to a high-frequency power amplifying device that can be used, and an electronic apparatus having a communication function in which the high-frequency power amplifying device is mounted.

  More specifically, a plurality of communication systems having different frequency bands, that is, a diversified communication system, or an amplifier (Amplifier) configured by an amplifying element such as a transistor that can handle a wide frequency band, and an output of the amplifier that is a preceding circuit A high-frequency power amplifying apparatus including a matching circuit that suppresses power loss by matching an impedance (characteristic impedance) and an input impedance (characteristic impedance) of a load, which is a subsequent circuit, and an electronic device having a communication function using the high-frequency power amplifying apparatus About.

  Examples of the electronic device include mobile devices such as a mobile phone, a portable information terminal, a wireless router, and a notebook personal computer compatible with the next generation mobile communication system.

  There is a method that uses a plurality of high-frequency power amplifiers corresponding to each frequency band as the simplest method corresponding to a plurality of bands. In the case of providing a plurality of high-frequency power amplifiers as described above, a plurality of matching circuits are required corresponding to the plurality of amplifying elements, and there is a problem that the cost is high.

In the prior art that can reduce the number of amplifying devices, a multiband amplifier (Japanese Patent Laid-Open No. 2008-113202) and a high-frequency power amplifying device (Japanese Patent Laid-Open No. 2008-118624) that can deal with signals in a plurality of frequency bands. No. Gazette) has been proposed.
However, the former requires a high-accuracy duplexer in order to cope with a plurality of bands, and there remain problems in area and cost. In the latter case, there is no disclosure or suggestion of achieving both wide bandwidth and high efficiency. Moreover, as far as the present applicant knows, such a high-frequency power amplifying apparatus has not been confirmed.

JP 2008-113202 A JP 2008-118624 A

One page of the Nikkei Business Daily July 8

  As a method of making the high-frequency power amplifying apparatus compatible with a wide band, for example, as shown in the above prior art (Japanese Patent Laid-Open No. 2008-118624), an impedance variable element is used in a matching circuit that matches the output impedance of the amplifier and the input impedance of the load. A method of changing the impedance is conceivable.

  However, this method can be applied to a high impedance design capable of ignoring a loss generated in a parasitic resistance, for example, a high frequency power amplifying apparatus having a relatively low output power of up to 100 mW for short-distance radio such as a wireless LAN. However, there is a problem that it cannot be applied to a low-impedance design in which loss generated in a parasitic resistance cannot be ignored, for example, a high-frequency power amplifying apparatus of a maximum 1 W class in a wide area radio such as a mobile phone.

  In other words, the impedance of a high-frequency power amplifier that requires a low voltage, for example, 3.3V power supply voltage and an output power of 1 W or more, is a low impedance of 1 to 3Ω, ignoring power loss due to parasitic resistance generated in the variable impedance element. This is because it cannot be done.

  In view of this point, the present invention is to provide a high-frequency power amplifying apparatus that can cope with a wide band and can achieve high efficiency with little power loss.

  It is another object of the present invention to provide a high-frequency power amplifying apparatus that is suitable for application to an electronic device that is required to be reduced in size and weight.

  Moreover, this invention is providing the electronic device which has a communication function carrying the said high frequency power amplifier.

  In order to achieve the above object, in the present invention, the output impedance of the amplifier is set higher than the impedance between the power amplifying element of the high-frequency power amplifying device and the variable impedance circuit including the impedance variable element constituting the matching circuit. An impedance conversion circuit for conversion is provided.

  In other words, the impedance matching is performed by the variable impedance circuit after the output impedance of the amplifier is converted to an impedance higher than the impedance by the impedance conversion circuit.

  For example, the present invention relates to a high frequency power amplifying apparatus comprising an amplifier and a matching circuit that matches the output impedance of the amplifier and the input impedance of a load. The matching circuit is disposed at a subsequent stage of the amplifier, and the output impedance of the amplifier is The high-frequency power amplifying apparatus includes an impedance conversion circuit that converts the impedance to a higher impedance than the impedance and a variable impedance circuit that changes the converted high impedance.

  The amplifier according to the present invention includes an amplifier configured with a low impedance capable of supporting a wide band or a plurality of bands, and the impedance conversion circuit includes a circuit including a fixed value element that converts the impedance to a higher impedance than the low impedance. The variable impedance circuit is composed of a circuit including a variable element that varies the high impedance converted by the impedance conversion circuit, and the impedance conversion circuit and the matching circuit including the variable impedance circuit can support a wide band or a plurality of bands. And the power efficiency of the frequency in the band is increased.

  The variable impedance circuit has an IC or modular configuration together with the amplifier. In addition, the impedance conversion circuit of the present invention has an IC or modular configuration together with the amplifier and the variable impedance circuit. The input signal has a desired wideband frequency (for example, a band for portable terminals of 700 MHz to 2.0 GHz or 2.3 to 2.7 GHz).

  Further, the present invention provides a high-frequency power amplifying device having one input terminal and a plurality of output terminals, one amplifier between the one input terminal and the plurality of output terminals, a first impedance conversion circuit, A first matching circuit including one variable impedance circuit, a second impedance conversion circuit, and a second matching circuit including a second variable impedance circuit are provided, and one of the first and second matching circuits is selected. It is a possible configuration.

  Further, for example, in the present invention, in the electronic device having a communication function in which the high frequency power amplifier is mounted, the matching circuit is arranged at a subsequent stage of the amplifier, and the output impedance of the amplifier is converted to an impedance higher than the impedance. And a variable impedance circuit that varies the converted high impedance. The variable impedance circuit is provided on the same semiconductor chip as the amplifier, and is formed into an IC or a module. The impedance conversion circuit is the semiconductor chip. An electronic device provided on a separate semiconductor chip or substrate and made into an IC or a module, the amplifier input terminal being connected to the input side circuit portion of the electronic device, and the output terminal being connected to the output side circuit portion of the electronic device It is.

  Furthermore, the present invention provides a high frequency power amplifying apparatus comprising an amplifier and a matching circuit for matching the output impedance of the amplifier and the input impedance of the load, wherein the matching circuit is arranged at the subsequent stage of the amplifier, and the output of the amplifier An impedance conversion circuit that converts an impedance to an impedance higher than the impedance, and a variable impedance circuit that changes the converted high impedance. The variable impedance circuit is provided on the same semiconductor chip as the amplifier, and is integrated into an IC or a module. This is a high frequency power amplifier.

  According to the present invention, it is possible to provide a high-efficiency high-frequency power amplifying apparatus that can cope with a wide band.

  In addition, according to the present invention, it is possible to provide an electronic device having a communication function that is compatible with a wide band and requires high efficiency.

The characteristic view which shows the relationship between load impedance, power efficiency, and frequency. The block diagram which shows an example of the variable matching circuit with the function to vary an impedance. The block diagram which shows the other example of the variable matching circuit with the function to vary an impedance. 1 is a basic configuration block diagram showing an embodiment of the present invention. The circuit diagram which shows an example of the high frequency power amplifier of this invention. The characteristic view which shows the mode of a frequency, a capacity | capacitance, and an inductive change at the time of ON of a switch element in the variable matching circuit of this invention. The characteristic view which shows the mode of a frequency, a capacity | capacitance, and an inductive change at the time of a switch element's ON in the variable matching circuit of this invention. The characteristic view which shows the mode of the change of the voltage amplitude in each (i) point and (ii) point of two variable matching circuits. The basic composition block diagram which shows the other Example of this invention. The circuit diagram which shows the other example of the high frequency power amplifier of this invention. The basic composition block diagram which shows the further another Example of this invention.

  For the purpose of realizing both broadband and power efficiency, the present invention provides a high-frequency power amplifying apparatus for converting impedance to an impedance (load impedance) higher than the output impedance of the amplifier, and a variable having a function of changing the converted impedance. This was realized by providing a matching circuit consisting of an impedance circuit.

  Before describing the embodiments of the present invention, the background art and the problems of the prior art will be described in more detail.

  First, it is generally necessary for an amplifier to match its output impedance with its input impedance. For matching of both the impedances, a matching circuit (matching circuit) composed of an inductor, a capacitor / capacitor, etc. is used.

  The reason for matching these impedances is to reduce the power loss of the high-frequency power amplifier as is well known. In other words, if there is a mismatch in impedance, power loss occurs and power efficiency decreases.

  The high-frequency power amplifier is generally made so as to correspond only to a specific frequency band of a communication device in which the high-frequency power amplifier is mounted, and the matching circuit is configured separately from the amplifier, for example, an amplifier A dedicated IC is formed separately from the IC or module.

  FIG. 1 is a characteristic diagram showing the relationship among load impedance, power efficiency, and frequency.

  This characteristic diagram shows how the matching circuit 1, the matching circuit 2, and the matching circuit 3 having different matching characteristics have a power loss due to impedance mismatch and a reduction in power efficiency. In the figure, the horizontal axis represents frequency, and the vertical axis represents load impedance and power efficiency.

  This reduction in power efficiency causes performance degradation due to heat generation and, for example, a decrease in the battery duration of the portable terminal. Therefore, it is desirable to suppress a decrease in power efficiency.

  In addition, communication methods are diversified, and also in this communication method, various frequency bands are used depending on the country / region / communication carrier. In wireless communication devices, particularly portable terminal transceivers, it is essential to support a plurality of frequency bands so that optimum communication can be performed at any time and anywhere (regardless of location).

  Conventionally, for a plurality of required frequency bands, for example, a plurality of individual high-frequency power amplifiers are prepared corresponding to each frequency band as in the prior art, and one high-frequency power amplifier is selected from them. It was normal to select and use a device.

  However, in the case of individually preparing high frequency power amplifying devices corresponding to a plurality of frequency bands or wide bands in this way, when these high frequency power amplifying devices are incorporated in a portable terminal which is a communication device, only that much. The size of the mobile terminal must be increased. In addition, the weight increases and the convenience as a portable terminal that is desired to be reduced in size and weight is impaired. In addition, there is a problem that the cost is high.

  As a method for solving such a problem, as described above, for example, as shown in FIG. 2, a matching circuit 14 is provided in the subsequent stage of the amplifier 13, and a part of the capacitors 146 of the matching circuit is variably configured (Variable Capacitor). Is the method. Alternatively, as shown in FIG. 3, a plurality of switches 144 and 144 are connected in series to a plurality of capacitors 142 and 142, and the switch value is a switch method in which the capacitor value is variable by turning on and off the switches.

In general, the matching circuit 14 is a capacitor (capacitance), an inductor (coil), or the like whose characteristics are capacitive or dielectric depending on the ratio of the wavelength and the line length, which are inversely proportional to the frequency, or an element whose impedance (electrical impedance) depends on the frequency. It is realized by combining transmission lines that change in nature. Therefore, the impedance of the matching circuit 14 also depends on the frequency, and it is not easy to match in a wide band.
Here, the transmission line is, for example, a microstrip line.
Line) and Coplaner Line (Coplaner)
Waveguide).

  On the other hand, in recent years, communication devices have a tendency to save power, and the power supply voltage of the entire transceiver is being lowered. A high-frequency power amplifying device mounted on a communication device is no exception. In the high frequency power amplifier, in order to reduce the power supply voltage without changing the maximum output power, it is necessary to reduce the output impedance of the amplifier constituting the high frequency power amplifier.

  For example, in an amplifier of several watts class used in a mobile phone or high-speed wireless communication, the output impedance of the amplifier needs to be an extremely low impedance of several Ω (about 2 Ω). In order to match with such a low impedance, a matching circuit that realizes a necessary load impedance of several Ω is required.

  Parasitic resistance always exists in the elements constituting the matching circuit 14 as is generally known. The electric power generated in the parasitic resistance becomes a power loss as described above. The parasitic resistance of the matching capacitor or inductor used individually according to the frequency is small with respect to the low impedance of several Ω to be realized, and the loss generated in the parasitic resistance can be ignored in many cases.

  On the other hand, when the above-described variable impedance circuit is used as a matching circuit in order to realize a broadband matching, the parasitic resistance such as a variable capacitor (variable capacitor) or a switch used is a matching capacitor or inductor. Greater than parasitic resistance. For this reason, the power loss is several times that of a narrow-band matching circuit that does not use a variable impedance circuit. Therefore, the loss generated in the parasitic resistance cannot be ignored.

  In general, the size of a variable capacitor or switch having a small parasitic resistance is several times larger than the size of a fixed capacitor or fixed inductor having a fixed capacitance value or inductor value. For this reason, for example, it is difficult to realize an amplifier by making the amplifier into an IC (dedicated IC or the like) or a module and incorporating a matching circuit in the amplifier IC / module.

The reason is that there is a great adverse effect due to parasitic resistance such as variable capacitors and switches. Further, the mounting area is increased, which is contrary to the area saving required for portable devices in recent years.
The present invention corrects the above-described problems, and examples thereof will be described below.

FIG. 4 is a block diagram showing the basic configuration of the high-frequency power amplifier of the present invention.
In the figure, reference numeral 100 denotes a high-frequency power amplifying apparatus capable of handling a wide band, and the high-frequency power amplifying apparatus includes an amplifier 13 for amplifying a signal input to the input terminal 11 and an output impedance of the amplifier 13 in the previous stage. A matching circuit 1415 for matching the load input impedance of the subsequent stage connected to the output terminal 12 is provided.

  The amplifier 13 amplifies the signal input to the input terminal 11, and is also intended to amplify power to output power of several watts class, for example. In order to operate the output power of several watts class with a low power supply voltage, for example, 3 V, the output impedance of the amplifier 13 is configured to be low impedance (for example, several Ω: 2 to 3 Ω).

  The input signal has a desired wide frequency band (for example, a band for a mobile terminal of 700 MHz to 2.0 GHz or 2.3 to 2.7 GHz).

  Further, the amplifier 13 is configured such that the output impedance is low in all the bands in order to be able to deal with various frequency bands, that is, to be able to deal with a wide band.

  In order to reduce the influence of the parasitic resistance, the matching circuit of the present invention reduces the output impedance of the amplifier 13 to an impedance higher than the impedance, and the impedance converted by the circuit. The variable impedance circuit 14 is configured to be variable.

  In the present invention, the impedance conversion circuit 15 means an assembly of elements whose main purpose is impedance conversion. The matching circuit 1415 means an assembly of elements whose main purpose is matching, and the impedance conversion circuit 15 is also included. The variable impedance circuit 14 means the following. That is, the variable impedance circuit 14 includes a circuit that can continuously change the value of each component element, a circuit that includes a variable element that can change the element value discretely using a switch element, or a discrete element. Includes a circuit capable of changing the impedance. For example, the variable impedance circuit 14 may be configured to be controllable in response to a control signal from a band control circuit described later. For example, when one frequency band is congested, it may be configured such that communication is possible by changing to another frequency band and switching or selecting.

  Here, as the matching circuit 1415, when the output impedance of the amplifier 13 and the input impedance of the load are configured only by the variable impedance circuit 14 as in the conventional case, the electric power generated in the parasitic resistance of the elements constituting the variable impedance circuit. Loss cannot be ignored, and there has been a problem that it is impossible to obtain a broadband and high-efficiency high-frequency power amplifier as described above.

  In order to correct such a problem, in the present invention, an impedance conversion circuit 15 that converts the output impedance of the amplifier 13 into an impedance higher than the impedance is provided between the amplifier 13 and the variable impedance circuit 14.

  The impedance conversion circuit 15 has a function of matching the output impedance of the amplifier 13 and the impedance of the load together with the variable impedance circuit 14.

  Here, the high impedance means an impedance that is higher than the output impedance of the amplifier 13 and that the high impedance has an adverse effect on the amplifier 13, that is, power loss caused by parasitic resistance can be ignored. Specifically, for example, when the output impedance of the amplifier 13 is designed to be 2 to 3Ω, it is several tens of Ω, for example, about 10 to 50Ω.

  Thereby, the power loss due to the parasitic resistance of the elements constituting the variable impedance circuit 14 can be reduced. As a result, it has become possible to obtain a broadband and highly efficient high-frequency power amplifier.

  As will be described later as another embodiment, the variable impedance circuit 14 can be integrated with the amplifier 13 into an IC or a module on the same semiconductor chip.

  The amplifier 13 is formed as an IC or a module and is configured by a combination of elements such as a transistor, a resistor, and a capacitor, but a known configuration can be used.

  The variable impedance circuit 14 is configured by a combination of elements such as capacitors and inductors capable of varying impedance. From this, it can be said that the variable impedance circuit 14 is a variable matching circuit.

  The impedance conversion circuit 15 is provided between the amplifier 13 and the variable impedance circuit 14, and the output impedance (for example, several Ω: 2-3 Ω) of the amplifier 13 is set to an impedance higher than the impedance (for example, several tens Ω: 10-50Ω). ) Is formed.

  The impedance conversion circuit 15 can be said to be a fixed matching circuit because the impedance conversion circuit is configured by a combination of elements such as a fixed value capacitor and a fixed value inductor.

  Here, the technical significance of variable in the variable impedance circuit (variable matching circuit) 14 includes continuously changing the frequency band as described above, and switching or selecting the frequency band. It is. Therefore, the variable impedance circuit 14 is a circuit for switching the frequency and selecting the selector as well as continuously changing the frequency band based on a frequency band variable control signal or the like. means.

  Incidentally, when the above-described high-frequency power amplifying apparatus is applied to, for example, a transmission circuit of a communication device, the input terminal 11 is connected to an input side circuit unit including a signal processing and modulation circuit, and the output terminal includes a transmission including an antenna. Connected to the circuit section.

  FIG. 5 is a circuit diagram showing a specific example of the impedance conversion circuit 15 and the variable impedance circuit 14 of the matching circuit 1415. In the figure, the impedance conversion circuit 15 is composed of, for example, a transmission line 151 and a capacitor. When it is desired to convert the impedance from 2Ω to 10Ω by the impedance conversion circuit 15 at 2 GHz, for example, the transmission line 151 has a characteristic impedance of 50Ω, an electrical length of 2 mm, and a capacitance of 15 pF.

  One end of the transmission line 151 is connected to the output side of the amplifier 13, and the other end is connected to the output terminal 12 via the transmission line 17. The other end is grounded via a capacitive element such as a chip capacitor.

  The variable impedance circuit 14 is connected in series with two capacitors (capacitors) 142 and 140 connected in series, and connected to the capacitor 140 in parallel, and receives a control signal (logic value 1 or 0) from the control circuit 18 to perform switching. The switch 144 is configured. The switch 144 is turned on when the control signal is “1”, and turned off when the control signal is “0”.

The switch 144 is, for example, an NMOS (Negative
Channel Metal Oxide Semiconductor) switch.
The control circuit 18 generates a control signal for the switch 144 based on the detection result of the frequency detector 19 and the power detector 20 or the signal from the mode control 21.
A frequency detector 19 detects a frequency and a change in the frequency transmitted and received by the high frequency power amplifying apparatus or an electronic device in which the high frequency power amplifying apparatus is mounted.
A power detector (Power Detector) 20 detects input / output power of the high-frequency power amplifying device or power transmitted / received by an electronic device in which the high-frequency power amplifying device is mounted.
The mode control 21 is used by the user when it is desired to switch and select a plurality of bands from the electronic device side according to the frequency usage status and the communication system standard, or to change the impedance in order to enable application to a wide band. It is what is done.
These control circuits and detectors may be provided on the electronic device side where the present high frequency power amplifier is mounted. The control circuit 18 can control the frequency detector 19, the power detector 20, and the mode control 21 if at least one of them is present.

  FIGS. 6 and 7 are configuration diagrams showing the variable impedance circuit 14 and characteristic diagrams showing changes in frequency, capacity, and inductive when the switch 144 is on and off.

  FIG. 6 shows a configuration example and characteristics of the variable impedance circuit 14 in which capacitors 141 and 142 and an inductor 143 are connected in series, and a switch 144 is connected to the capacitor 142.

  FIG. 7 shows a configuration example in which capacitors 141 and 142 and an inductor 143 are connected in parallel, and a switch 144 is connected to the capacitor 142 and its characteristics.

  6 and 7, the variable impedance circuit 14 is configured by the combination of each element, and the inductivity is controlled by changing the capacitor value by turning the switch 144 on and off to change the impedance. A solid line is a characteristic curve in which the switch 144 is off and a dotted line is an ob. When the switch 144 is turned on, the frequency curve or the like is varied from a solid line to a dotted line.

  As described above, when the impedance conversion circuit 15 converts the output impedance of the amplifier 13 to a high impedance, the voltage amplitude increases compared to before the conversion, and the breakdown voltage may exceed the breakdown voltage when the switch 144 is off.

  FIGS. 8A and 8B show the states of the capacitor 142 and the switch 144 of the variable impedance circuit 14 at that time, and FIG. 8C shows each of the variable impedance circuits 14 of FIGS. It is a characteristic view which shows the mode of the change of the voltage amplitude in (i) point and (ii) point. In the figure, the horizontal axis indicates time (Time), and the vertical axis indicates voltage amplitude (Voltage).

  As a countermeasure when the voltage amplitude increases and the switch 144 exceeds the withstand voltage when the switch 144 is turned off, a capacitor (capacitance) having one terminal grounded between the capacitor 142 and the switch 144 connected in series as shown in FIG. ) 140 is connected, and the variable impedance circuit 14 for changing the impedance is used. According to the variable impedance circuit 14, since the voltage amplitude is divided by the capacitor even when the switch 144 is turned off, the withstand voltage required for the switch 144 can be reduced.

  As described above, in this embodiment, the impedance conversion circuit 15 converts the output impedance of the amplifier 13 to a higher impedance than the impedance, and then the variable impedance circuit 14 in the subsequent stage changes the impedance, The input impedance is matched with the input impedance.

  Here, for example, the load impedance of several Ω necessary for a high-frequency power amplifier of the class of several watts is increased 5 to 10 times by the impedance conversion circuit 15 using a capacitor or inductor having a fixed capacitance value with low power loss. By converting, power loss due to parasitic resistance in the variable impedance circuit 14 can be reduced.

  As a result, compared to the case where the variable impedance circuit 14 is arranged immediately after the amplifier 13, it is possible to achieve high efficiency (reduction of power loss due to parasitic resistance of the variable impedance circuit 14) while supporting a wide band.

  Further, according to the present embodiment, with a simple configuration that merely provides the impedance conversion circuit 15 that converts the output impedance of the amplifier to a high impedance, the power load efficiency of the high-frequency power amplifier is maintained at or close to the optimum state. Broadband can be achieved. For example, it is possible to cover 20 bands (bands) of 700 MHz band and 2 GHz band mainly used in the high frequency power amplifier with one high frequency power amplifier by the band switching function.

  9 and 10 are a block diagram and a circuit diagram showing another embodiment of the present invention. In this embodiment, the amplifier 13 has an IC or module configuration, and the variable impedance circuit 14 has an IC or module configuration together with the amplifier IC or module.

  The impedance conversion circuit 15 described above has an external configuration, the input terminal of the impedance conversion circuit 15 is connected to the output terminal of the amplifier 13, and the output terminal of the impedance conversion circuit 15 is connected to a transmission line such as a microstrip line (Microstrip Line), This is connected to the variable impedance circuit 14 using a bonding wire 17. For example, the impedance conversion circuit 15 converts the impedance of the amplifier 13 from 2 Ω to 10 Ω, and the connection 17 between the impedance conversion circuit 15 and the 50 Ω signal output terminal 12 is formed with a characteristic impedance of 50 Ω and an electrical length of 11 mm. The connection between the terminal 12 and the variable impedance circuit 14 is formed by a bonding wire having an inductor of about 1 nH. The capacitors 140 and 142 in the variable impedance circuit 14 are 1.2 pF, and the capacitor 145 is 1.1 pF. At this time, when the switch 144 is on, matching is performed at 2.0 GHz, and when the switch 144 is off, matching is performed at 1.7 GHz.

  According to such an embodiment, in addition to the effects of the first embodiment described above, for example, a bonding wire can be used as an inductor, which can reduce the number of components, reduce the area, that is, reduce the size, and reduce the number of parts. Cost can be reduced.

That is, since the variable impedance circuit 14 has an IC or module configuration together with the amplifier 13, even if the parasitic resistance of the impedance variable element or the switch element constituting the variable impedance circuit 14 is large, the impedance conversion circuit 15 causes the amplifier 13 to Since the output impedance is converted to a high impedance, the influence of the parasitic resistance on the amplifier 13 can be ignored from the relationship with the impedance of the variable impedance circuit 14, and the power loss can be suppressed. Therefore, the variable impedance circuit 14 can be built in the amplifier IC or the amplifier module, and can be realized with a size that can be built. For example, it is possible to reduce the area / size to a few mm square, that is, at least about 5 mm × 5 mm.
In the present embodiment, the impedance conversion circuit 15 has a module configuration separately from the amplifier 13 and the variable impedance circuit 14, but may be configured so as to be built in the amplifier IC or the amplifier module together with the variable impedance circuit 14. In this case, further miniaturization can be expected.

  FIG. 11 is a block diagram showing an application example of the second embodiment shown in FIGS. In this embodiment, a plurality of, for example, two variable impedance circuits 14 and two impedance conversion circuits 15 described above are prepared for one amplifier 13 and are configured by two paths, for example, transmission lines or bonding wires as shown in the figure. Is.

  That is, the output of the amplifier 13 is branched and input to the respective impedance conversion circuits 15 and 15. The impedance conversion circuits 15 and 15 respectively convert the signals to a desired high impedance, return the high impedance converted signals to the separate variable impedance circuits 14 and 14, and impedance matching is performed by these variable impedance circuits.

  According to such an embodiment, a plurality of frequencies can be individually controlled. In other words. One frequency can be selected and used from among a plurality of frequencies, and it is possible to respond to the demands of the telecommunications carrier by a simple method. In particular, when the present high frequency power amplifier is mounted on a communication device, the convenience of the communication device can be further improved.

  Further, the impedance of the matching circuit on the unused terminal side of the two output terminals 12 and 12 can be made close to an open or short circuit in an alternating manner, and the matching circuit of a plurality of paths can be used properly, so that high efficiency and wide band can be achieved.

  The above-described high-frequency power amplifying apparatus of the present invention can be applied to communication equipment such as a portable terminal. In this case, for example, a circuit including a signal processing circuit and a modulation circuit is an input side circuit unit of the high frequency power amplifier, and a transmission circuit unit including an antenna is an output side (load side) circuit unit.

  According to the present embodiment described above, a single high-frequency power amplifying device can handle a plurality of bands, and is suitable for battery-powered mobile devices with low power consumption.

  The present invention is not limited to a communication device equipped with a high-frequency power amplifier circuit, but can be applied to any electronic device equipped with a high-frequency power amplifier circuit and having a communication function. For example, the present invention can be applied to communication devices such as mobile phones and information processing devices including routers and personal computers.

DESCRIPTION OF SYMBOLS 100 High frequency power amplifier 11 Signal input terminal 12 Signal output terminal 13 Amplifier 14 Variable impedance circuit (variable matching circuit)
15 Impedance conversion circuit (fixed matching circuit)
16 Amplifier IC / Module 17 Connection (transmission line / bonding wire)
18 Control Circuit 19 Frequency Detector 20 Power Detector 21 Band Control

Claims (13)

In a high-frequency power amplifying apparatus including an amplifier and a matching circuit that matches an output impedance of the amplifier and an input impedance of a load,
The matching circuit is arranged at a subsequent stage of the amplifier, an impedance conversion circuit for converting the output impedance of the amplifier into an impedance higher than the impedance, and a variable impedance circuit for matching the converted high impedance with the load impedance. A high-frequency power amplifying device comprising: The amplifier comprises a low impedance amplifier capable of supporting a wide band or a plurality of bands,
The impedance conversion circuit comprises a circuit including a fixed value element that converts the impedance to a higher impedance than the low impedance,
The variable impedance circuit comprises a circuit including a variable element that varies the high impedance converted by the impedance conversion circuit,
2. The high frequency power amplifying apparatus according to claim 1, wherein the matching circuit including the impedance conversion circuit and the variable impedance circuit can support a wide band or a plurality of bands.   2. The high frequency power amplifying apparatus according to claim 1, wherein each element of a capacitor and a switch is used for the variable impedance circuit, and the high impedance is varied by the elements to match the high impedance with the load impedance.   2. The high frequency device according to claim 1, wherein each of the elements of a capacitor, an inductance, and a switch is used in the variable impedance circuit, and the inductivity or the capacitance of the variable impedance circuit is controlled by a combination of the elements. Power amplification device.   The high-frequency power amplifier according to claim 1, wherein the variable impedance circuit is configured as an IC or a module together with the amplifier.   2. The high frequency power amplifying apparatus according to claim 1, wherein the impedance conversion circuit is configured as an IC or a module together with the amplifier and the variable impedance.   7. The high frequency power amplifier according to claim 5, wherein a second capacitor is connected in parallel to the switch in the variable impedance circuit in which the first capacitor and the switch are configured in series.   The variable impedance circuit is a part of the circuit, and a wiring portion connected to the variable impedance circuit arranged in a preceding stage of the circuit is formed of a bonding wire or a transmission line, and the inductance of the wire or the transmission line is reduced. 7. The high frequency power amplifier according to claim 5, wherein the high frequency power amplifier is used.   The high-frequency power amplifier includes one input terminal and a plurality of output terminals. One amplifier, a first impedance conversion circuit, and a first variable impedance are provided between the one input terminal and the plurality of output terminals. A first matching circuit including a circuit, a second impedance conversion circuit, and a second matching circuit including a second variable impedance are provided, and one of the first and second matching circuits can be selected. The high-frequency power amplifier according to any one of claims 1 to 8. 2. The electronic device having a communication function in which the high-frequency power amplifying device according to claim 1 is mounted, wherein the circuit is arranged at a subsequent stage of the amplifier, and impedance conversion for converting an output impedance of the amplifier into an impedance higher than the impedance. A circuit and a variable impedance circuit that varies the converted high impedance,
The variable impedance circuit is provided on the same semiconductor chip as the amplifier to be an IC or a module, and the impedance conversion circuit is provided on a semiconductor chip or substrate separate from the semiconductor chip to be an IC or a module,
An electronic device, wherein an input terminal of the amplifier is connected to an input side circuit unit of the electronic device, and an output terminal is connected to an output side circuit unit of the electronic device. In a high-frequency power amplifying apparatus including an amplifier and a matching circuit that matches an output impedance of the amplifier and an input impedance of a load,
The matching circuit is arranged at a subsequent stage of the amplifier, an impedance conversion circuit for converting the output impedance of the amplifier into an impedance higher than the impedance, and a variable impedance circuit for matching the converted high impedance with the load impedance. Consists of
The variable impedance circuit is provided on the same semiconductor chip as the amplifier, and is formed as an IC or a module.   12. The high frequency power amplifier according to claim 11, wherein the impedance conversion circuit is provided on the same semiconductor chip as the semiconductor chip together with the variable impedance circuit, and is formed as an IC or a module.   An electronic device having a communication function, wherein the high-frequency power amplifier according to claim 11 or 12 is mounted.

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