Method of manufacturing radio frequency power amplifier

Abstract

To provide a radio frequency power amplifier capable of achieving miniaturization and broadband.SOLUTION: In a radio frequency power amplifier, an input signal distributor 40 distributes a first input signal RF1 at a radio frequency into a second input signal RF2 and a third input signal RF3, and outputs the second input signal to a balanced amplifier 10. In the balanced amplifier, two output ends that output two amplified radio frequency signals with a phase difference of 90° from each other are coupled to a first port P1 and a second port P2 of a hybrid coupler 30, respectively. A control amplifier 20 amplifies the third input signal and outputs an amplified third input signal from an output end. A power supply voltage Vcc in common is supplied to the balanced amplifier and the control amplifier. The hybrid coupler varies a load impedance of the balanced amplifier coupled to the first port and the second port, according to a current level of a radio frequency signal inputted to a third port P3 from the control amplifier.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a high frequency power amplifier. [Background technology]

[0002] The load modulation balanced amplifier (LMBA) has attracted attention as a technology for realizing a highly efficient high-frequency power amplifier (Non-Patent Document 1). In the LMBA disclosed in Non-Patent Document 1, the balanced amplifier is biased in class AB, and the control amplifier that modulates the load impedance of the balanced amplifier is biased in class C. Two high-frequency signals with a 90° phase difference output from the balanced amplifier and a high-frequency signal output from the control amplifier are combined by a hybrid coupler and supplied to the load. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] K. Takenaka, et al., "Load-Modulated Balanced Amplifier Design for Handset Applications", IEEE Microwave and Wireless Techology Letters, Vol. 33, No. 6, JUNE 2023 Summary of the Invention [Problem to be solved by the invention]

[0004] In the LMBA disclosed in Non-Patent Document 1, an impedance matching circuit is inserted between the control amplifier and the hybrid coupler in order to operate the balance amplifier and control amplifier with high power added efficiency using a single power supply. This impedance matching circuit is a factor that hinders miniaturization of the device and widening the bandwidth of the high-frequency amplifier.

[0005] An object of the present invention is to provide a high frequency power amplifier that can be made smaller and has a wider bandwidth. [Means for solving the problem]

[0006] According to one aspect of the present invention, a hybrid coupler having a first port, a second port, a third port, and a fourth port to which a load is connected; an input signal divider that divides a high-frequency first input signal into a second input signal and a third input signal; a balanced amplifier that receives the second input signal and outputs two amplified high-frequency signals having a phase difference of 90° from each other, the two output terminals of which are connected to the first port and the second port, respectively; a control amplifier, the output terminal of which amplifies and outputs the third input signal, being coupled to the third port without passing through any circuit component that affects impedance matching; Equipped with a common power supply voltage is supplied to the balance amplifier and the control amplifier; a voltage level of the first input signal at a rising edge of the current output from the control amplifier is higher than a voltage level of the first input signal at a rising edge of the current output from the balance amplifier; The hybrid coupler is provided with a high-frequency power amplifier that changes the load impedance of the balanced amplifier coupled to the first port and the second port depending on the current level of the high-frequency signal input from the control amplifier to the third port. [Effects of the Invention]

[0007] The output terminal of the balanced amplifier is connected to the third port of the hybrid circuit without passing through any circuit components that affect impedance matching, which allows for the device to be made more compact. Furthermore, the degradation of wideband characteristics caused by inserting an impedance matching circuit is suppressed. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram of a high-frequency power amplifier according to a first embodiment. [Figure 2] FIG. 2 is a schematic equivalent circuit diagram for explaining the operation of the hybrid coupler 30. As shown in FIG. [Figure 3] FIG. 3 is a block diagram of a radio frequency power amplifier according to a comparative example. [Figure 4] FIG. 4A is a graph showing the relationship between the input voltage of the first input signal RF1 (FIG. 3) and the currents IBA, ICSP, and ICA, FIG. 4B is a graph showing the relationship between the input voltage of the first input signal RF1 and the voltages VBA, VCSP, and VCA, and FIG. 4C is a graph showing the relationship between the input voltage and the load impedances ZBA, ZCSP, and ZCA. [Figure 5] FIG. 5A is a graph showing the relationship between the input voltage of the first input signal RF1 (FIG. 1) and the currents IBA, ICSP, and ICA; FIG. 5B is a graph showing the relationship between the input voltage of the first input signal RF1 and the voltages VBA, VCSP, and VCA; and FIG. 5C is a graph showing the relationship between the input voltage of the first input signal RF1 and the load impedances ZBA, ZCSP, and ZCA. [Figure 6] FIG. 6 is a graph showing the relationship between the input voltage of the first input signal RF1 and the voltages VBA, VCSP, and VCA when the rising point of the current ICA is changed in the high-frequency power amplifier according to the first embodiment. [Figure 7] FIG. 7 is a graph showing the relationship between the input voltage and the power added efficiency of the high frequency power amplifier according to the first embodiment. [Figure 8] FIG. 8 is a schematic plan view of a hybrid coupler 30 used in a radio frequency power amplifier according to a modified example of the first embodiment. [Figure 9] FIG. 9 is a schematic perspective view of a hybrid coupler 30 used in a radio frequency power amplifier according to another modification of the first embodiment. [Figure 10] FIG. 10 is an equivalent circuit diagram of a hybrid coupler 30 used in a high-frequency power amplifier according to yet another modification of the first preferred embodiment. [Figure 11] FIG. 11 is a block diagram of a high-frequency power amplifier according to the second embodiment. [Figure 12]FIG. 12 is a block diagram of a high-frequency power amplifier according to the third embodiment. [Figure 13] FIG. 13 is a block diagram of a high-frequency power amplifier according to the fourth embodiment. [Figure 14] FIG. 14 is a block diagram of a communication device according to the fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] [First Example] A radio frequency power amplifier according to a first embodiment will be described with reference to FIGS. 1 to 5C.

[0010] 1 is a block diagram of a radio frequency power amplifier according to the first embodiment. The radio frequency power amplifier according to the first embodiment includes a balanced amplifier 10, a control amplifier 20, a hybrid coupler 30, and an input signal distributor 40. The radio frequency power amplifier according to the first embodiment and its peripheral circuits will be described below.

[0011] Input terminal T in A high-frequency signal input from is input to the drive stage amplifier 50 via an impedance matching circuit 51. This high-frequency signal is a radio frequency band signal modulated by a predetermined communication method. A power supply voltage Vcc is supplied to the drive stage amplifier 50 via a choke coil L. The drive stage amplifier 50 amplifies the input high-frequency signal and outputs a first input signal RF1. The first input signal RF1 amplified by the drive stage amplifier 50 is input to the input signal distributor 40.

[0012] The input signal divider 40 divides the first input signal RF1 and outputs a second input signal RF2 and a third input signal RF3. The input signal divider 40 may be, for example, a 3 dB coupler using a coupled transmission line, a Wilkinson divider, or the like. For example, the signal levels of the second input signals RF2 and RF3 are 3 dB lower than the signal level of the first input signal RF1, and there is a 90° phase difference between them. The signal levels and phase difference between the second input signal RF2 and the third input signal RF3 may be other values. The second input signal RF2 is input to the balanced amplifier 10, and the third input signal RF3 is input to the control amplifier 20.

[0013] The balanced amplifier 10 includes two amplifiers 12A and 12B that amplify two high-frequency signals obtained by dividing the second input signal RF2. The amplifiers 12A and 12B are configured, for example, with heterojunction bipolar transistors (HBTs). For example, a divider 11 divides the second input signal RF2 into two high-frequency signals. These two high-frequency signals have equal signal levels and a 90° phase difference between them. For example, a 3 dB coupler using a coupled transmission line can be used as the divider 11. A class AB bias is applied to each of the amplifiers 12A and 12B. A power supply voltage Vcc is supplied to each of the amplifiers 12A and 12B via a choke coil L.

[0014] A class C bias is applied to the control amplifier 20, which amplifies the third input signal RF3. The control amplifier 20 is configured, for example, with a heterojunction bipolar transistor (HBT). A power supply voltage Vcc is supplied to the control amplifier 20 via a choke coil L. In other words, the balanced amplifier 10 and the control amplifier 20 operate on a single power supply voltage Vcc.

[0015] The hybrid coupler 30 is composed of a main line 30A and a secondary line 30B that are electromagnetically coupled to each other. One end of the main line is referred to as the first port P1, and the other end is referred to as the fourth port P4. The end of the secondary line on the side of the first port P1 is referred to as the third port P3, and the end on the side of the fourth port P4 is referred to as the second port P2.

[0016] The output terminals of the two amplifiers 12A and 12B are respectively coupled to a first port P1 and a second port P2 of the hybrid coupler 30. The output terminal of the control amplifier 20 is coupled to a third port of the hybrid coupler 30. The fourth port P4 of the hybrid coupler 30 is coupled to an output terminal T out Output terminal T out is connected to a load, such as an antenna.

[0017] The high-frequency signals input to the first port P1 and the second port P2 are combined and output from the fourth port P4. The high-frequency signal input to the third port P3 is output from the fourth port P4. That is, a high-frequency signal with power equivalent to the sum of the powers of the high-frequency signals input to the first port P1, the second port P2, and the third port P3 is output from the fourth port P4. The load impedance of the two amplifiers 12A and 12B of the balanced amplifier 10 varies depending on the current level of the high-frequency signal input from the control amplifier 20 to the third port P3. More specifically, the load impedance of the two amplifiers 12A and 12B of the balanced amplifier 10 varies depending on the ratio between the current level of the high-frequency signal input from the control amplifier 20 to the current level of the high-frequency signal input from the balanced amplifier 10 to the first port P1 and the second port P2.

[0018] The operation of the hybrid coupler 30 will now be described in more detail with reference to FIG. 2 is a schematic equivalent circuit diagram for explaining the operation of the hybrid coupler 30. A current −I is supplied to the first port P1, the second port P2, and the third port P3, respectively. BA , jI BA , and -I CSP e jφ Assume that a current source is connected to the first port P1, the second port P2, and the third port P3. The current sources connected to the first port P1, the second port P2, and the third port P3 correspond to the amplifiers 12A and 12B of the balanced amplifier 10 and the control amplifier 20 (FIG. 1), respectively. Here, j is the imaginary unit and φ is the phase offset.

[0019] A load RL is connected to the fourth port P4. The current flowing from the load RL to the fourth port P4 is defined as -I L The voltages generated at the first port P1, the second port P2, the third port P3, and the fourth port P4 are denoted as V BA2 , V BA1 , V CSP , V L The load impedances seen from the first port P1, the second port P2, and the third port P3 to the load side are respectively denoted as Z BA2 , Z BA1 , Z CSP It is marked as follows.

[0020] The current flowing into the hybrid coupler 30 and the voltage generated at each port are expressed by the following relational expressions using the impedance matrix of the hybrid coupler 30.

number

[0021] Expanding equation (1), the load impedance Z BA1 , Z BA2 is expressed by the following formula:

number

number

[0022] Voltage V BA1 , V BA2 is expressed by the following formula:

number

[0023] From equation (2), the load impedance Z BA1 , ZBA2 are equal, and the current I input to the third port P3 CSP and phase offset φ. On the other hand, the load impedance Z seen from the third port P3 is CSP is constant.

[0024] Next, a radio frequency power amplifier according to a comparative example and its operation will be described with reference to FIGS. 3 to 4C.

[0025] 3 is a block diagram of a radio frequency power amplifier according to a comparative example. In the radio frequency power amplifier according to the first embodiment (FIG. 1), the output end of the control amplifier 20 and the third port P3 of the hybrid coupler 30 are directly connected, but in the comparative example, an impedance matching circuit 55 is inserted between them.

[0026] The current and voltage at each port of the hybrid coupler 30 are denoted in the same manner as the current and voltage shown in FIG. 2. The load impedance seen from the output end of the control amplifier 20 to the load side is Z. CA The current output from the control amplifier 20 is denoted as -I CA e jφ The voltage at the output terminal of the control amplifier 20 is V CA It is marked as follows.

[0027] FIG. 4A shows the input voltage of the first input signal RF1 (FIG. 3) and the current I BA , I CSP , I CA 4B is a graph showing the relationship between the input voltage of the first input signal RF1 and the voltage V BA , V CSP , V CA 4A and 4B, the horizontal axis represents the input voltage normalized by its maximum value. The vertical axis of FIG. 4A represents the current, I BA The vertical axis of FIG. 4B represents the voltage V BA It is expressed as a value normalized by the maximum value of .

[0028] Since the balanced amplifier 10 is biased by class AB, as shown in FIG. 4A, the current I BA rises, and as the input voltage rises, the current I BA increases almost linearly. When the normalized value of the input voltage reaches 1, the current I BA The normalized value of is 1. Since the control amplifier 20 is given a class C bias, the current I BA When the normalized value of the input voltage is 0.5, the current I CA The current I CA At the same time as the rise of CSP The current I CSP , I CA increases linearly with increasing input voltage level.

[0029] current I CSP The slope of the current I BA The slope of -1 / 2 When the voltage V BA becomes constant (see equation (4)). By utilizing this relationship, the balanced amplifier 10 can be operated as a carrier amplifier of a Doherty amplifier.

[0030] To maximize the power-added efficiency of a high-frequency power amplifier, when the normalized value of the input voltage is 1 (i.e., the input voltage is at its maximum value), the voltage V BA and voltage V CA In FIG. 4B, when the normalized value of the input voltage is 1, the voltage V BA and voltage V CA Generally, the current I CA is the current I CSP does not match the voltage V CSP is the voltage V CA does not match.

[0031] Figure 4C shows the relationship between the input voltage and the load impedance Z BA , Z CSP , Z CA1 is a graph showing the relationship between the input voltage and the load impedance. The horizontal axis represents the input voltage as a normalized value, and the vertical axis represents the load impedance as a value normalized by the characteristic impedance Z0 of the hybrid coupler 30. CSP In the range of 0, the load impedance Z BA The normalized value of is 1 (see equation (2)). The load impedance Z CSP The normalized value of is also 1 (see equation (3)).

[0032] current I CSP and I CA and do not match, and the voltage V CSP and V CA Since the load impedance Z CA and the load impedance Z CSP Therefore, in the comparative example, an impedance matching circuit 55 (FIG. 3) must be inserted between the output end of the control amplifier 20 and the third port P3 of the hybrid coupler 30.

[0033] Next, the operation of the high frequency power amplifier according to the first embodiment will be described with reference to Figures 5A, 5B, and 5C. Figure 5A shows the relationship between the input voltage of the first input signal RF1 (Figure 1) and the current I BA , I CSP , I CA 5B is a graph showing the relationship between the input voltage of the first input signal RF1 and the voltage V BA , V CSP , V CA 5C is a graph showing the relationship between the input voltage of the first input signal RF1 and the load impedance Z BA , Z CSP , Z CA 10 is a graph showing the relationship between

[0034] In the comparative example (Fig. 4A), the current I CA The normalized value of the input voltage at the time of rising is set to 0.5, but in the first embodiment, the current I CA The normalized value of the input voltage during the rising edge of is set to 0.4 (Figure 5A). CSP The normalized value of the input voltage also rises at 0.4. At this time, the current I CAThe slope of the current I CSP Similarly, the slope of the current I BA The slope of -1 / 2 When the normalized value of the input voltage is 1, the voltage V CA The normalized value of the current I reaches 1 (Figure 5B). CSP and current I CA Since the voltage V CSP Also, voltage V CA Matches.

[0035] current I CA and I CSP and the voltage V CA and V CSP Since the load impedance Z CA and Z CSP Since the two match, the impedance matching circuit 55 (FIG. 3) inserted in the comparative example is not necessary in the first embodiment.

[0036] Next, the excellent effects of the first embodiment will be described. In the first embodiment, as shown in FIG. 2, under the condition that the balance amplifier 10 and the control amplifier 20 are driven by a single power supply voltage Vcc, as shown in FIG. 5B, the voltage V BA and the voltage V at the output terminal of the control amplifier 20 CA Therefore, when the input voltage is at its maximum value, the balance amplifier 10 and the control amplifier 20 can be operated simultaneously with high efficiency.

[0037] In this way, high efficiency can be achieved without inserting an impedance matching circuit between the control amplifier 20 and the third port P3 of the hybrid coupler 30. Since there is no need to place an impedance matching circuit between the output end of the control amplifier 20 and the third port P3 of the hybrid coupler 30, it is possible to reduce the size of the device. Furthermore, it is possible to suppress degradation of wideband characteristics caused by the impedance matching circuit.

[0038] Next, a radio frequency power amplifier according to a modification of the first embodiment will be described. In the first embodiment, as shown in FIG. 1 , no impedance matching circuit is inserted between the output end of the control amplifier 20 and the third port P3 of the hybrid coupler 30, and the output end of the control amplifier 20 is directly connected to the third port P3 of the hybrid coupler 30. Here, "directly connected" means that no circuit components that substantially affect the impedance of high-frequency signals are connected. For example, as shown in FIG. 1 , a choke coil L that exhibits substantially infinite impedance to high-frequency signals may be connected between the power supply wiring and the wiring connecting the output end of the control amplifier 20 and the third port P3 of the hybrid coupler 30. Alternatively, for example, a DC-blocking capacitor or the like that exhibits substantially zero impedance to high-frequency signals may be inserted between the output end of the control amplifier 20 and the third port P3 of the hybrid coupler 30.

[0039] Next, a radio frequency power amplifier according to another modification of the first embodiment will be described with reference to Figures 6 and 7. In the first embodiment, as shown in Figure 5B, the voltage V BA and the voltage V at the output terminal of the control amplifier 20 CA In order to roughly match the maximum value of CA The normalized value (hereinafter sometimes referred to as the rising point) of the input voltage (voltage level of the first input signal RF1 (FIG. 1)) when the current I rises is set to approximately 0.4. CA A preferred range for the rising point of will be described below.

[0040] Figure 6 shows the current I CA The input voltage of the first input signal RF1 when the rising point of BA , V CSP , V CA 6 is a graph showing the relationship between the current I and the horizontal and vertical axes, respectively. The horizontal and vertical axes are the same as the horizontal and vertical axes of the graph shown in FIG. 5B. The solid lines a, b, and c in the graph of FIG. 6 respectively represent the current I CAVoltage V when the rising point is set to 0.37, 0.41, and 0.45 BA dashed lines d, e, and f indicate the current I CA Voltage V when the rising point is set to 0.37, 0.41, and 0.45 CA , V CSP In Figure 6, the numbers in parentheses attached to the solid and dashed lines represent the current I CA This shows the rising point of

[0041] If the rise point is set to 0.41, the voltage V BA and voltage V CA This almost coincides with the maximum value of V. Therefore, it can be seen that high efficiency can be obtained. BA and voltage V CA However, the difference is less than 20% of the normalized value of the voltage. With this level of deviation, the high-frequency power amplifier can maintain a sufficiently high efficiency. Therefore, in order to maintain a high efficiency of the high-frequency power amplifier, it is necessary to set the current I CA It is preferable to set the rising point of 0.37 or more and 0.45 or less.

[0042] In addition, to maintain a higher efficiency of the high-frequency power amplifier, the voltage V BA and voltage V CA It is more preferable to set the difference between the maximum value of the current I and the normalized value of the voltage to 10% or less. CA It is more preferable to set the rising point of 0.39 or more and 0.43 or less.

[0043] 7 is a graph showing the relationship between input power and power-added efficiency of the high-frequency power amplifier according to the first embodiment. The horizontal axis represents the ratio of input power to the maximum input power in units of dB, and the vertical axis represents the power-added efficiency in units of %. In the graph of FIG. 7, solid lines g, h, and i respectively represent the current I CAThe power-added efficiency is shown when the rising point of the current I is 0.37, 0.41, and 0.45. In Fig. 7, the numbers in parentheses next to the solid line indicate the power-added efficiency when the rising point of the current I is 0.37, 0.41, and 0.45. CA This shows the rising point of

[0044] current I CA It can be seen that the input power ratio at which the power-added efficiency peaks varies depending on the rise point of the current I CA When the rise point of is set to 0.37, the efficiency is higher than when other rise points are set. When the input power ratio is in the range of about -7 dB or more, the current I CA When the rise point of is set to 0.45, the efficiency is higher than when other rise points are set. When the input power ratio is in the range of approximately -8.5 dB to -7 dB, the current I CA When the rising point is set to 0.41, the efficiency is higher than when other rising points are set.

[0045] Thus, the current I CA By changing the rise point of the input power ratio, the range of input power ratios at which high efficiency is obtained changes.

[0046] Next, a radio frequency power amplifier according to yet another modification of the first embodiment will be described with reference to Figures 8, 9, and 10. In the first embodiment, a 3 dB coupler formed of a coupled transmission line is used as the hybrid coupler 30 (Figure 1). In the modification described below, another coupler is used as the hybrid coupler 30.

[0047] 8 is a schematic plan view of a hybrid coupler 30 used in a radio frequency power amplifier according to a modification of Example 1. In this modification, a branch line coupler is used as the hybrid coupler 30.

[0048] This hybrid coupler 30 is composed of four transmission lines 31A, 31B, 31C, and 31D, each with a length equivalent to a quarter wavelength, arranged along the periphery of a square. As an example, the transmission lines 31A, 31B, 31C, and 31D are arranged clockwise in this order. The characteristic impedance of the transmission lines 31A and 31C is Z0, and the characteristic impedance of the transmission lines 31B and 31D is Z0 / 2. 1 / 2 is.

[0049] The connection point between transmission lines 31A and 31B corresponds to the first port P1, the connection point between transmission lines 31A and 31D corresponds to the second port P2, the connection point between transmission lines 31C and 31D corresponds to the third port P3, and the connection point between transmission lines 31B and 31C corresponds to the fourth port P4.

[0050] 9 is a schematic perspective view of a hybrid coupler 30 used in a radio frequency power amplifier according to another modification of Example 1. In this modification, a parallel plate coupler is used as the hybrid coupler 30.

[0051] This hybrid coupler 30 includes rectangular conductive flat plates 32A and 32B that face each other in parallel. One corner of one flat plate 32A corresponds to a first port P1, and the opposite corner corresponds to a fourth port P4. The corner of the other flat plate 32B that overlaps with the corner of the first port P1 corresponds to a third port P3, and the corner on the opposite side of the long side corresponds to a second port P2.

[0052] 10 is an equivalent circuit diagram of a hybrid coupler 30 used in a high-frequency power amplifier according to yet another modification of Example 1. In this modification, a lumped parameter coupler is used as the hybrid coupler 30.

[0053] This hybrid coupler 30 includes a pair of inductors 33A and 33B and capacitors 33C and 33D that are magnetically coupled to each other. One end of the inductor 33A corresponds to the third port P3, and the other end corresponds to the second port P2. The end of the other inductor 33B on the third port P3 side corresponds to the first port P1, and the opposite end corresponds to the fourth port P4. Capacitor 33C is connected between the first port P1 and the third port P3, and capacitor 33D is connected between the second port P2 and the fourth port P4.

[0054] As shown in FIGS. 8, 9, and 10, the hybrid coupler 30 may be a branch line coupler, a parallel plate coupler, a lumped constant coupler, or the like.

[0055] [Second Example] Next, a radio frequency power amplifier according to a second embodiment will be described with reference to Fig. 11. Below, description of configurations common to the radio frequency power amplifier according to the first embodiment described with reference to Figs. 1 to 5C will be omitted.

[0056] 11 is a block diagram of a high-frequency power amplifier according to the second embodiment. In the first embodiment (FIG. 1), a power supply voltage Vcc is supplied to each of the two amplifiers 12A and 12B of the balanced amplifier 10 and the control amplifier 20 via a choke coil L. In other words, a dedicated power supply line is provided for each of the two amplifiers 12A and 12B of the balanced amplifier 10 and the control amplifier 20.

[0057] In contrast to this, in the radio frequency power amplifier according to the second embodiment, the power supply voltage Vcc is supplied from the output terminal of the amplifier 12B (the output terminal of the balance amplifier 10 connected to the second port) to the control amplifier 20 via the sub-line 30B of the hybrid coupler 30. The control amplifier 20 does not have a dedicated power supply line, and the power supply line for the amplifier 12B is used as part of the power supply line for the control amplifier 20.

[0058] Next, the excellent effects of the second embodiment will be described. In the second embodiment, a dedicated power supply line for the control amplifier 20 is not required, which makes it possible to reduce the size of the device.

[0059] [Third Example] Next, a radio frequency power amplifier according to a third embodiment will be described with reference to Fig. 12. Below, description of the configuration common to the radio frequency power amplifier according to the second embodiment described with reference to Fig. 11 will be omitted.

[0060] In the second embodiment (FIG. 11), a 3 dB coupler including a coupled transmission line is used as the hybrid coupler 30. In contrast, in the third embodiment, a branch-line coupler is used as the hybrid coupler 30. In the branch-line coupler, the first port P1, the second port P2, the third port P3, and the fourth port P4 are all DC-short-circuited. This allows the hybrid coupler 30 to be used as part of a DC power supply line.

[0061] In the second embodiment (FIG. 11), a dedicated power supply line is provided for each of the two amplifiers 12A and 12B of the balanced amplifier 10. In contrast, in the high-frequency power amplifier according to the third embodiment, a power supply line is provided for only one of the two amplifiers 12A and 12B. For example, a power supply line is provided for one amplifier 12A, and a dedicated power supply line is not provided for the other amplifier 12B.

[0062] A power supply voltage Vcc is supplied from a power supply line connected to one amplifier 12A to the other amplifier 12B via a first port P1 and a second port P2 of the hybrid coupler 30. Furthermore, a power supply voltage Vcc is supplied from a power supply line connected to the amplifier 12A to the control amplifier 20 via the hybrid coupler 30.

[0063] Next, the excellent effects of the third embodiment will be described. In the third embodiment, not only is a dedicated power supply line not required for the control amplifier 20, but also for one amplifier 12B of the balance amplifier 10, so it is possible to further reduce the size of the device.

[0064] [Fourth Example] Next, a radio frequency power amplifier according to a fourth embodiment will be described with reference to Fig. 13. Below, description of configurations common to the radio frequency power amplifier according to the first embodiment described with reference to Figs. 1 to 5C will be omitted.

[0065] 13 is a block diagram of a high-frequency power amplifier according to Example 4. In Example 1 (FIG. 1), a dedicated power supply line is provided for each of the two amplifiers 12A and 12B of the balanced amplifier 10 and the control amplifier 20.

[0066] In contrast, the radio frequency power amplifier according to the fourth embodiment has one power supply line shared by three components: two amplifiers 12A and 12B of the balanced amplifier 10, and the control amplifier 20. A transmission line transformer is used as the impedance matching circuit 53 connected to the fourth port P4 of the hybrid coupler 30. The transmission line transformer includes a main line 53A and a sub-line 53B that are electromagnetically coupled to each other.

[0067] The input port of the main line 53A is connected to the fourth port P4, and the passing port is connected to the output terminal T out The isolated port of the sub-line 53B is connected to the input port of the main line 53A. The coupled port of the sub-line 53B is grounded via a capacitor C in terms of high frequency, and is connected via a choke coil L to the power supply wiring of the power supply voltage Vcc in terms of DC.

[0068] The power supply voltage Vcc is supplied to the two amplifiers 12A and 12B of the balanced amplifier 10 and the control amplifier 20 via the sub-line 53B of the impedance matching circuit 53 and the hybrid coupler 30, respectively.

[0069] Next, the excellent effects of the fourth embodiment will be described. In the fourth embodiment, part of the power supply line is shared by the two amplifiers 12A and 12B of the balance amplifier 10 and the control amplifier 20, which makes it possible to reduce the size of the device.

[0070] The radio frequency power amplifier according to the first embodiment can achieve high efficiency even when operated with a single power supply voltage without inserting an impedance matching circuit between the output end of the control amplifier 20 and the third port P3 of the hybrid coupler 30. Therefore, as in the second, third, and fourth embodiments, it is possible for at least two of the two amplifiers 12A and 12B of the balanced amplifier 10 and the control amplifier 20 to share a power supply line.

[0071] [Fifth Example] Next, a communication device according to a fifth embodiment will be described with reference to Fig. 14. Fig. 14 is a block diagram of the communication device according to the fifth embodiment. The communication device according to the fifth embodiment includes a transceiver IC 90, multiple transmission systems 80, a multiplexer 91, and an antenna 92. Each of the multiple transmission systems 80 includes a high-frequency power amplifier 81, a first switch 82, multiple filter circuits 83, and a second switch 84. The high-frequency power amplifier 81 is a high-frequency power amplifier according to the first, second, third, or fourth embodiment.

[0072] A radio frequency signal to be transmitted is input from a transceiver IC 90 to each radio frequency power amplifier 81 of a plurality of transmission systems 80. The radio frequency signal amplified by the radio frequency power amplifier 81 is input to one filter circuit 83 selected by a first switch 82. The radio frequency signal that has passed through the filter circuit 83 is transmitted to an antenna 92 ​​via a second switch 84 and a multiplexer 91.

[0073] Next, the excellent effects of the fifth embodiment will be described. In the fifth embodiment, a radio frequency power amplifier according to the first, second, third or fourth embodiment is used as radio frequency power amplifier 81, and therefore a single power supply voltage is used, and highly efficient operation can be achieved while suppressing degradation of wideband characteristics.

[0074] The above-described embodiments are merely examples, and it goes without saying that partial substitution or combination of the configurations shown in different embodiments is possible. Similar effects resulting from similar configurations of multiple embodiments will not be mentioned sequentially for each embodiment. Furthermore, the present invention is not limited to the above-described embodiments. For example, it will be obvious to those skilled in the art that various modifications, improvements, combinations, etc. are possible.

[0075] Based on the above examples described in this specification, the following invention is disclosed. <1> a hybrid coupler having a first port, a second port, a third port, and a fourth port to which a load is connected; an input signal divider that divides a high-frequency first input signal into a second input signal and a third input signal; a balanced amplifier that receives the second input signal and outputs two amplified high-frequency signals having a phase difference of 90° from each other, the two output terminals of which are connected to the first port and the second port, respectively; a control amplifier, the output terminal of which amplifies and outputs the third input signal, being coupled to the third port without passing through any circuit component that affects impedance matching; Equipped with a common power supply voltage is supplied to the balance amplifier and the control amplifier; a voltage level of the first input signal at a rising edge of the current output from the control amplifier is higher than a voltage level of the first input signal at a rising edge of the current output from the balance amplifier; The hybrid coupler is a radio frequency power amplifier that changes the load impedance of the balanced amplifier coupled to the first port and the second port depending on the current level of the radio frequency signal input from the control amplifier to the third port.

[0076] <2> The load impedance of the balance amplifier when the current from the control amplifier is not rising is equal to the load impedance of the control amplifier when the current from the control amplifier is rising. <1> The high frequency power amplifier according to claim 1.

[0077] <3> the balanced amplifier, the control amplifier, and the hybrid coupler are configured so that, when the voltage level of the first input signal is increased, after a current from the control amplifier rises, the voltage level of the output terminal of the balanced amplifier becomes constant; When the maximum value of the voltage level of the first input signal is 1, the voltage level of the first input signal at the rise of the current from the control amplifier is 0.37 or more and 0.45 or less. <1> or <2> The high frequency power amplifier according to claim 1.

[0078] <4> the hybrid coupler includes a coupled transmission line including a main line having the first port and the fourth port as both ends and a sub-line having the third port and the second port as both ends, A power supply voltage is supplied to the control amplifier from the output end of the balanced amplifier connected to the second port via the sub-line of the hybrid coupler. <1> ~ <3> 10. The high-frequency power amplifier according to claim 9, wherein:

[0079] <5> the hybrid coupler is a branch-line coupler; A power supply voltage is supplied from the output terminal of one of the amplifiers of the balanced amplifier to the other amplifier of the balanced amplifier and the control amplifier via the branch line coupler. <1> ~ <3> 10. The high-frequency power amplifier according to claim 9, wherein:

[0080] <6> further comprising a transmission line transformer disposed between the fourth port and a load; the hybrid coupler is a branch-line coupler; A power supply voltage is supplied to the balance amplifier and the control amplifier via the transmission line transformer and the hybrid coupler. <1> ~ <3> 10. The high-frequency power amplifier according to claim 9, wherein: [Explanation of symbols]

[0081] 10 Balanced Amplifier 11 Distributor 12A, 12B amplifiers 20 Control Amplifier 30 Hybrid Coupler 30A main line 30B sub line 31A, 31B, 31C, 31D Transmission Lines 32A, 32B flat plate 33A, 33B inductors 33C, 33D capacitors 40 Input signal distributor 50 Drive stage amplifier 51, 53, 55 Impedance matching circuit 53A main line 53B Sub-line 80 Transmission System 81 High frequency power amplifier 82 First Switch 83 Filter Circuit 84 Second Switch 90 Transceiver IC 91 Multiplexer 92 Antenna

Claims

1. a hybrid coupler having a first port, a second port, a third port, and a fourth port to which a load is connected; an input signal divider that divides a high-frequency first input signal into a second input signal and a third input signal; a balanced amplifier to which the second input signal is input, and which outputs two amplified high-frequency signals having a phase difference of 90° from each other, the two output terminals of which are respectively connected to the first port and the second port; a control amplifier for amplifying and outputting the third input signal, the output terminal of which is coupled to the third port without passing through any circuit component that affects impedance matching; Equipped with a common power supply voltage is supplied to the balance amplifier and the control amplifier; a voltage level of the first input signal at a rising edge of the current output from the control amplifier is higher than a voltage level of the first input signal at a rising edge of the current output from the balance amplifier; The hybrid coupler is a radio frequency power amplifier that changes the load impedance of the balanced amplifier coupled to the first port and the second port depending on the current level of the radio frequency signal input from the control amplifier to the third port.

2. 2. The radio frequency power amplifier according to claim 1, wherein a load impedance of the balanced amplifier when a current from the control amplifier is not rising is equal to a load impedance of the control amplifier when a current from the control amplifier is rising.

3. the balanced amplifier, the control amplifier, and the hybrid coupler are configured so that, when the voltage level of the first input signal is increased, after a current from the control amplifier rises, the voltage level of the output terminal of the balanced amplifier becomes constant; 3. The radio frequency power amplifier according to claim 1, wherein when a maximum value of a voltage level of the first input signal is 1, a voltage level of the first input signal at a rise time of a current from the control amplifier is 0.37 or more and 0.45 or less.

4. the hybrid coupler includes a coupled transmission line including a main line having the first port and the fourth port as both ends and a sub-line having the third port and the second port as both ends, 3. The radio frequency power amplifier according to claim 1, wherein a power supply voltage is supplied to the control amplifier from the output end of the balanced amplifier connected to the second port via the sub-line of the hybrid coupler.

5. the hybrid coupler is a branch-line coupler; 3. The high frequency power amplifier according to claim 1, wherein a power supply voltage is supplied from an output terminal of one of the balanced amplifiers to the other of the balanced amplifiers and the control amplifier via the branch line coupler.

6. further comprising a transmission line transformer disposed between the fourth port and a load; the hybrid coupler is a branch-line coupler; 3. The high frequency power amplifier according to claim 1, wherein a power supply voltage is supplied to the balanced amplifier and the control amplifier via the transmission line transformer and the hybrid coupler.

Images