JP2019103130A - Transmission unit - Google Patents

Abstract

To provide a transmission unit capable of improving power efficiency without depending on the breadth of a band width.SOLUTION: A transmission unit comprises: a power amplifier module outputting an amplifier signal by amplifying an electric power of an input signal; and a power supply module supplying a power supply voltage to the power amplifier module on the basis of a first control signal in accordance with a band width of the input signal. The power supply module modulates the power supply voltage in accordance with an amplitude level of the input signal in the case where the band width of the input signal is a first band width on the basis of the first control voltage, and modulates the power supply voltage in accordance with an average output power of the power amplifier module in the case where the band width of the input signal is a second band width wider than the first band width.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a transmission unit.

  In a mobile communication device such as a cellular phone, a power amplification module is used to amplify the power of a radio frequency (RF: Radio Frequency) signal to be transmitted to a base station. In recent years, in mobile phones, communication standards such as Long Term Evolution (LTE) and LTE-Advanced, which are standards for high-speed data communication, have been adopted. In such communication standards, in order to improve the communication speed, PAPR (Peak-to-Average Power Ratio), which is the ratio of peak power to average power of an RF signal, often increases. As described above, even when PAPR is large, a high power supply voltage is required to maintain high linearity, and power consumption in the power amplification module tends to be large. On the other hand, in mobile phones, it is required to reduce power consumption in order to increase the time available for calls and communications.

  In order to cope with this problem, for example, Patent Document 1 discloses a transmission apparatus adopting an envelope tracking (ET) scheme, which improves power efficiency by controlling a power supply voltage according to the amplitude level of a modulation signal. It is disclosed. In the power supply device included in the transmission device, a power supply voltage that follows the fluctuation of the amplitude of the modulation signal is generated by combining the switching amplifier unit and the linear amplifier unit.

International Publication No. 2013/133170

  On the other hand, in a communication standard that realizes high-speed data communication, the bandwidth of the RF signal is increasingly wide due to the modulation method. For example, in 5G (5th generation mobile communication system), the bandwidth may exceed 50 MHz. As described above, when a signal with a wide bandwidth is amplified by an ET transmitter as disclosed in Patent Document 1, a large amount of current is injected to the linear amplifier unit to suppress delay in tracking of the power supply voltage. There is a need to. As a result, the power consumption in the linear amplifier unit is increased, and as a result, there is a problem that the power efficiency of the entire transmission apparatus is reduced.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a transmission unit capable of improving power efficiency regardless of the width of a bandwidth.

  In order to achieve such an object, a transmission unit according to one aspect of the present invention is based on a power amplification module that amplifies the power of an input signal and outputs an amplification signal, and a first control signal according to the bandwidth of the input signal. A power supply module for supplying a power supply voltage to the power amplification module, and the power supply module determines the amplitude level of the input signal based on the first control signal when the bandwidth of the input signal is the first bandwidth. Accordingly, the power supply voltage is fluctuated, and when the bandwidth of the input signal is a second bandwidth wider than the first bandwidth, the power supply voltage is fluctuated according to the average output power of the power amplification module.

  According to the present invention, it is possible to provide a transmission unit capable of improving power efficiency regardless of the width of the bandwidth.

It is a figure which shows the structural example of the transmission unit which concerns on 1st Embodiment of this invention. It is a figure showing the circuit composition of transmitting unit 100A concerning a 1st embodiment of the present invention. FIG. 6 is an image diagram showing the relationship between the bandwidth and the power efficiency when the transmission unit 100A according to the first embodiment of the present invention operates in accordance with various schemes. It is a figure showing the example of composition of power amplification module 140 (power amplification module 140B). It is a figure showing the example of composition of power amplification module 140 (power amplification module 140C). It is a figure showing the example of composition of power supply module 130 (power supply module 130B). It is a figure showing the circuit composition of transmitting unit 100B concerning a 2nd embodiment of the present invention. FIG. 2 is a diagram showing an example of configuration of a multi-level back switching amplifier 202. It is an image figure showing the relation between bandwidth and power efficiency in case transmission unit 100B concerning a 2nd embodiment of the present invention operates according to various methods. FIG. 16 is an image diagram showing a relationship between output power and power efficiency when the power supply voltage generation method is an ET method or a discrete level ET method and the power amplification method is a normal amplification operation. FIG. 16 is an image diagram showing a relationship between output power and power efficiency when the generation method of the power supply voltage is the ET method or the discrete level ET method and the power amplification method is the Doherty operation. It is an image figure which shows the relationship between the bandwidth in the operation | movement pattern A which can be implement | achieved by the transmission unit 100B, and power efficiency. It is a figure which shows the circuit structure of the transmission unit 100C which concerns on 3rd Embodiment of this invention. It is an image figure which shows the relationship between the bandwidth in the operation | movement pattern B which can be implement | achieved by the transmission unit 100C, and power efficiency. It is a figure which shows the circuit structure of transmission unit 100D which concerns on 4th Embodiment of this invention. It is an image figure which shows the relationship between the bandwidth in the operation | movement pattern C which can be implement | achieved by transmission unit 100D, and power efficiency.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same element and the overlapping description is abbreviate | omitted.

  FIG. 1 is a diagram showing an example of the configuration of a transmission unit according to the first embodiment of the present invention. The transmission unit 100 shown in FIG. 1 is used, for example, to transmit various signals such as voice and data to a base station in a mobile communication device such as a mobile phone. The transmission unit 100 may be, for example, 2G (2nd generation mobile communication system), 3G (3rd generation mobile communication system), 4G (4th generation mobile communication system), 5G (5th generation mobile communication system), LTE (Long Generation Mobile Communication System) Term Evolution) A transmission signal is generated according to a communication standard such as Frequency Division Duplex (FDD), Time Division Duplex (LTE-TDD), LTE-Advanced, and LTE-Advanced Pro. The mobile communication device also includes a receiving unit for receiving a signal from the base station, but the description is omitted here.

  As shown in FIG. 1, the transmission unit 100 includes, for example, a baseband unit 110, an RF unit 120, a power supply module 130, a power amplification module 140, a front end unit 150, and an antenna 160.

  The baseband unit 110 modulates an input signal such as voice or data based on a modulation scheme such as quadrature amplitude modulation (QAM) or orthogonal frequency division multiplexing (OFDM), and modulates the modulation signal. Output The frequency of the modulation signal is, for example, about several MHz to several hundred MHz. Also, the baseband unit 110 supplies the control signal Ctrl1 (first control signal) for switching the method of generating the power supply voltage supplied to the power amplification module 140 to the power supply module 130 to amplify the power of the RF signal. A control signal Ctrl2 (second control signal) for switching the method is supplied to the power amplification module 140. Further, the baseband unit 110 supplies the power supply module 130 with an envelope signal Env corresponding to the envelope of the modulation signal. A specific example of the generation method of the power supply voltage and a specific example of the amplification method of the power will be described later. For example, the envelope signal Env may be supplied from the RF unit 120 to the power supply module 130 instead of the baseband unit 110.

  The RF unit 120 generates an RF signal RFin for wireless transmission from the modulated signal output from the baseband unit 110. The frequency of the RF signal RFin is, for example, about several hundred MHz to several tens of GHz, and has different bandwidths depending on communication standards and frequency bands. The control signals Ctrl1 and Ctrl2 output from the above-described baseband unit 110 correspond to the bandwidth of the RF signal RFin.

  The power supply module 130 generates a voltage Vreg in a generation method of a power supply voltage according to the control signal Ctrl1 supplied from the baseband unit 110 based on a predetermined power supply voltage Vbatt, and supplies the voltage Vreg to the power amplification module 140. Specifically, when the bandwidth of the RF signal RFin is a relatively narrow first bandwidth (for example, about 0 MHz to 50 MHz, more preferably 5 MHz or more and less than 50 MHz), the power supply module 130 conforms to the ET scheme. In this case, the power supply module 130 outputs, as a power supply voltage, a voltage Vreg that fluctuates according to the envelope signal Env (that is, fluctuates according to the amplitude level of the modulation signal). On the other hand, if the bandwidth of the RF signal RFin is a second bandwidth (for example, 50 MHz or more) wider than the first bandwidth, the power supply module 130 follows an average power tracking (APT) scheme. In this case, the power supply module 130 outputs, as a power supply voltage, a voltage Vreg that fluctuates according to the average output power of the power amplification module 140. As described above, the power supply module 130 generates the power supply voltage of the power amplification module 140 according to the power supply voltage generation method including the ET method and the APT method according to the bandwidth of the RF signal.

  The power amplification module 140 is based on the control signal Ctrl2 supplied from the baseband unit 110 and the voltage Vreg supplied from the power supply module 130 to a level necessary to transmit the power of the RF signal RFin to the base station. It amplifies and outputs amplified signal RFout.

  The front end unit 150 performs filtering of the amplified signal RFout, switching with a received signal received from the base station, and the like. The amplified signal output from the front end unit 150 is transmitted to the base station via the antenna 160.

  Next, specific configurations of the power supply module 130 and the power amplification module 140 will be described with reference to FIG.

  FIG. 2 is a diagram showing a circuit configuration of the transmission unit 100A according to the first embodiment of the present invention. In FIG. 2, the front end portion 150 and the antenna 160 are not shown.

  The power supply module 130A includes, for example, a boost switching amplifier 200, a back switching amplifier 201, a differential amplifier 210, a linear amplifier 220, and an inductor L1. Among these components, components excluding the inductor L1 are formed in, for example, the same power supply IC 131A.

  The boost switching amplifier 200 and the buck switching amplifier 201 are switching type voltage converters that respectively generate a voltage obtained by boosting or stepping down the power supply voltage Vbatt of a predetermined level. The boost switching amplifier 200 and the back switching amplifier 201 are each configured by, for example, a switch mode power supply (SMPS). The boost switching amplifier 200 and the back switching amplifier 201 have higher power efficiency but slower response than the linear amplifier 220 described later.

  The differential amplifier 210 amplifies and outputs the envelope signal Env supplied from the baseband unit 110 when the power supply module 130A generates the power supply voltage according to the ET system. In the present embodiment, the envelope signal Env is differentially output, and the differential amplifier 210 amplifies and outputs the differential signal. The envelope signal may not be differentially output. In this case, the power supply module 130A does not include the differential amplifier 210, and for example, an envelope signal is directly supplied to the linear amplifier 220.

  The linear amplifier 220 has a voltage follower configuration in which the output signal is fed back to the input. Specifically, when the power supply module 130A generates the power supply voltage according to the ET method, the linear amplifier 220 is supplied with the power supply voltage according to the power supply voltage Vbatt from the boost switching amplifier 200, and the envelope signal Env from the differential amplifier 210. The amplified signal is supplied, and a voltage corresponding to the amplitude of the signal is output. Thereby, the voltage Vreg (that is, a voltage according to the amplitude level of the RF signal RFin) corresponding to the amplitude level of the modulation signal is output from the power supply module 130A. The linear amplifier 220 responds faster but has lower power efficiency than the boost switching amplifier 200 and the buck switching amplifier 201. As described above, the power supply module 130A includes the boost switching amplifier 200 and the back switching amplifier 201, which are different in nature, and the linear amplifier 220 in combination, so that the voltage Vreg follows the fluctuation of the modulation signal amplitude with low delay and high efficiency. Can be generated.

  The boost switching amplifier 200, the back switching amplifier 201, the differential amplifier 210, and the linear amplifier 220 are switched on or off according to the control signal Ctrl1 supplied from the baseband unit 110, respectively. Specifically, when the power supply module 130A generates a power supply voltage according to the ET method, the boost switching amplifier 200, the back switching amplifier 201, the differential amplifier 210, and the linear amplifier 220 are all turned on. Thereby, the voltage Vreg which fluctuates according to the envelope signal Env is output. On the other hand, when the power supply module 130A generates a power supply voltage according to the APT method, the boost switching amplifier 200, the differential amplifier 210, and the linear amplifier 220 are turned off, and only the back switching amplifier 201 is turned on (see dashed line in FIG. 2). . In this case, the back switching amplifier 201 functions as a DC-DC converter, and outputs a voltage Vreg corresponding to the average output power of the power amplification module 140A via the inductor L1.

  The on state of the boost switching amplifier 200, the back switching amplifier 201, the differential amplifier 210, and the linear amplifier 220 may be controlled by, for example, a bias voltage or a bias current supplied to each amplifier from a bias circuit (not shown). .

  The power amplification module 140A includes, for example, a driver amplifier 300, a carrier amplifier 310, a peak amplifier 320, a divider 330, a combiner 340, and a bias circuit 350.

  The driver amplifier 300 amplifies the RF signal RFin supplied from the RF unit 120 and supplies the RF signal RFin ′ (input signal) to the distributor 330. The driver amplifier 300 is not particularly limited, but is configured of, for example, a bipolar transistor such as a heterojunction bipolar transistor (HBT) or a field effect transistor such as a metal-oxide-semiconductor field-effect transistor (MOSFET). The same applies to the carrier amplifier 310 and the peak amplifier 320.

  The carrier amplifier 310, the peak amplifier 320, the distributor 330, and the synthesizer 340 constitute a so-called Doherty amplifier that further amplifies the RF signal RFin '.

  The divider 330 divides the RF signal RFin ′ into an RF signal RF1 (first signal) supplied to the carrier amplifier 310 and an RF signal RF2 (second signal) supplied to the peak amplifier 320. The distributor 330 is configured of, for example, an inductor, a resistive element, and a capacitor. The RF signals RF1 and RF2 output from the distributor 330 are distributed, for example, such that the phase difference is approximately 90 degrees.

  The carrier amplifier 310 amplifies the input RF signal RF1 (first signal), and outputs an RF signal RF3 (third signal). The peak amplifier 320 amplifies the input RF signal RF2 (second signal) and outputs an RF signal RF4 (fourth signal). When the carrier amplifier 310 and the peak amplifier 320 function as a so-called Doherty amplifier (hereinafter also referred to as “Doherty operation”), the carrier amplifier 310 operates regardless of the power level of the RF signal RFin ′. On the other hand, peak amplifier 320 operates in a region where the power level of RF signal RFin 'is equal to or higher than the maximum level by a predetermined level lower (backoff point). Thus, only the carrier amplifier 310 operates in a region where the power level of the RF signal RFin 'is relatively low (region below the back-off point). Further, in a region where the power level of the RF signal RFin ′ is relatively high (region above the back-off point), both the carrier amplifier 310 and the peak amplifier 320 operate. Thus, the Doherty amplifier is more efficient than the configuration using only one amplifier by including the carrier amplifier 310 operating in the vicinity of the saturated output power in a region where the power level of the RF signal RFin ′ is relatively high. Is an improved configuration.

  The combiner 340 combines the RF signal RF3 output from the carrier amplifier 310 and the RF signal RF4 output from the peak amplifier 320, and outputs an amplified signal RFout. The combiner 340 doubles as an impedance matching function of converting one or both of the output impedance of the carrier amplifier 310 and the output impedance of the peak amplifier 320 while converting the phases of the RF signal RF3 and the RF signal RF4. For example, when the phase difference between the RF signal RF1 and the RF signal RF2 is approximately 90 degrees, the combiner 340 converts the phase so that the phase difference between the RF signal RF3 and the RF signal RF4 is approximately 0 degree.

  The bias circuit 350 supplies a bias current or a bias voltage to each of the driver amplifier 300, the carrier amplifier 310, and the peak amplifier 320. The bias circuit 350 controls the on state or off state and the operating point of the driver amplifier 300, the carrier amplifier 310 and the peak amplifier 320 by adjusting the bias current or the bias voltage based on the control signal Ctrl2. In other words, the control signal Ctrl2 is a signal that controls the bias current or the bias voltage generated by the bias circuit 350. The bias circuit 350 may control the gains of the driver amplifier 300, the carrier amplifier 310, and the peak amplifier 320 by adjusting the bias current or the bias voltage.

  The voltage Vreg is supplied as a power supply voltage from the power supply module 130A to the driver amplifier 300, the carrier amplifier 310, and the peak amplifier 320, respectively.

  The power amplification module 140A operates according to different amplification schemes according to the bandwidth of the RF signal. Specifically, when the bandwidth of the RF signal is relatively narrow and the power supply module 130A generates a power supply voltage according to the ET method, the power amplification module 140A performs a normal amplification operation, not a Doherty operation. In this case, the bias circuit 350 adjusts the bias current or bias voltage so that, for example, the carrier amplifier 310 and the peak amplifier 320 operate at the same operating point. Thereby, both the carrier amplifier 310 and the peak amplifier 320 are turned on regardless of the power level of the RF signal RFin '. Carrier amplifier 310 and peak amplifier 320 may be biased to be, for example, either class A operation or class AB operation. In order to distinguish the amplification operation at this time from the Doherty operation, “normal amplification Also called "action".

  On the other hand, when the bandwidth of the RF signal is relatively wide and the power supply module 130A generates a power supply voltage according to the APT method, the power amplification module 140A performs a Doherty operation. In this case, the bias circuit 350 adjusts the bias current or the bias voltage such that the carrier amplifier 310 is in the class A operation or the class AB operation and the peak amplifier 320 is in the class C operation. Thus, power efficiency can be improved as compared to the case where both carrier amplifier 310 and peak amplifier 320 perform class A operation or class AB operation.

Next, with reference to FIG. 3, an effect of switching the generation method of the power supply voltage and the amplification method of the power in the transmission unit 100A will be described. FIG. 3 is an image diagram showing the relationship between the bandwidth and the power efficiency when the transmission unit 100A according to the first embodiment of the present invention operates in accordance with various schemes. The combinations of the power supply voltage generation method and the power amplification method shown in the figure are as shown in Table 1 below. In the graph shown in FIG. 3, the horizontal axis indicates the bandwidth (MHz) of the RF signal, and the vertical axis indicates the power efficiency.

  As shown in FIG. 3 (1), in the case of the combination of the APT method and the normal amplification operation, the power efficiency is constant regardless of the bandwidth. On the other hand, as shown in FIG. 3 (2), in the case of the combination of the APT method and the Doherty operation, the power efficiency is improved as compared with the normal amplification operation. This is because, as described above, in the Doherty operation, the carrier amplifier 310 operates in a state near saturation as the output power increases.

  On the other hand, as shown in FIG. 3 (3), in the case of a combination of the ET scheme and a normal amplification operation, in a region where the bandwidth is relatively narrow (for example, about 0 MHz to 50 MHz), it is shown in (2). More power efficient than Doherty operation. This is because in the ET system, voltage Vreg is dynamically adjusted according to the amplitude level of the modulation signal. However, in the ET system, as the bandwidth becomes wider, the amount of current to be supplied to the linear amplifier 220 increases in order to suppress the delay of the linear amplifier 220. Therefore, the current consumption in the linear amplifier 220 increases, and as a result, the power efficiency of the entire transmission unit decreases. For example, in the region of 50 MHz or more, as shown in FIG. 3, the combination of the ET scheme and the normal amplification operation has lower power efficiency than the combination of the APT scheme and the Doherty operation.

  Here, for example, in the communication standard such as 3G, 4G or LTE which is the current communication standard, when the bandwidth of the RF signal is in the range of about 1.4 MHz to 20 MHz, high efficiency may be obtained by the ET method. it can. However, in the new communication standard such as 5G, the bandwidth of the RF signal may be about 5 MHz to 100 MHz. Accordingly, in such a new communication standard, there is no problem if the bandwidth is a narrow frequency band, but if the bandwidth is a wide frequency band, there is a problem that the power efficiency may be deteriorated in the ET system.

  In order to address this problem, in this embodiment, the ET system and the APT system can be suitably functioned by switching the generation system of the power supply voltage according to the bandwidth of the RF signal. That is, in the transmission unit 100A, the power supply module 130A is controlled to follow the ET method when the bandwidth is narrow and the APT method when the bandwidth is wide. As a result, for example, power efficiency can be improved regardless of the width of the bandwidth as compared with the configuration that always follows the ET method.

  Furthermore, in the transmission unit 100A, the power amplification module 140A is controlled to perform a normal amplification operation when the bandwidth is narrow and perform a Doherty operation when the bandwidth is wide. As a result, power efficiency can be further improved as compared with the configuration in which the normal amplification operation is performed regardless of the width of the bandwidth. Note that the power supply voltage generation method and the power amplification method are, for example, points where the power efficiency in the combination of the ET method and the normal amplification operation crosses the power efficiency in the combination of the APT method and the Doherty operation (see FIG. May be switched at about 50 MHz).

  Further, in the transmission unit 100A, the power amplification module 140A is shared in the normal amplification operation and the Doherty operation. As a result, for example, as compared with a configuration including different power amplification modules for each power amplification scheme, it is possible to improve power efficiency while suppressing an increase in circuit area.

  Although FIG. 2 shows a configuration in which the power amplification module 140A includes an amplifier (driver amplifier 300) of the first stage and an amplifier (carrier amplifier 310 and peak amplifier 320) of the second stage, the power amplification module is an amplifier of the first stage. It does not have to be provided. Alternatively, the power amplification module may include three or more stages of amplifiers.

  Further, the power supply voltage supplied to driver amplifier 300 may be a predetermined voltage instead of voltage Vreg.

  FIG. 4 and FIG. 5 are diagrams showing configuration examples of the power amplification module 140, respectively. Note that, in the present embodiment and the subsequent embodiments, descriptions of matters common to the above-described embodiment will be omitted, and only differences will be described. In particular, the same operation and effect by the same configuration will not be sequentially referred to in each embodiment.

  The power amplification module 140B shown in FIG. 4 and the power amplification module 140C shown in FIG. 5 respectively show a specific configuration example of the combiner 340 shown in FIG.

  In the power amplification module 140B, the combiner 340A includes a quarter wavelength line 400 and a combining unit 410.

  The quarter wavelength line 400 is connected in series between the output of the carrier amplifier 310 and the combining unit 410. The combining unit 410 combines the RF signal RF3 via the quarter wavelength line 400 with the RF signal RF4. The quarter wavelength line 400 delays the phase of the RF signal RF3 output from the carrier amplifier 310 by approximately 90 degrees. Thus, when the phase of the RF signal RF1 is advanced approximately 90 degrees from the phase of the RF signal RF2 in the divider 330, the phase difference between the RF signal RF3 and the RF signal RF4 is approximately 0 degree in the combining unit 410 and is combined. Ru.

  In the power amplification module 140C, the combiner 340B includes a combining unit 410, an inductor L2 and a capacitor C1.

  The inductor L2 is connected in series between the output of the carrier amplifier 310 and the combining unit 410. The capacitor C 1 (first capacitor) is connected in series between the output of the peaking amplifier 320 and the combining unit 410. The inductor L2 and the capacitor C1 have functions of phase shifters for converting the phases of the RF signals RF3 and RF4, respectively. For example, the inductor L2 delays the phase of the RF signal RF3 output from the carrier amplifier 310 by approximately 45 degrees. On the other hand, capacitor C1 advances the phase of RF signal RF4 output from peak amplifier 320 by approximately 45 degrees. Thus, when the phase of the RF signal RF1 is advanced by about 45 degrees in the divider 330 and the phase of the RF signal RF2 is delayed by about 45 degrees, the phase difference between the RF signal RF3 and the RF signal RF4 is about 0 in the combining unit 410. And it is synthesized.

  Such a configuration of the power amplification modules 140B and 140C may be applied to the power amplification module 140 shown in FIG. The power amplification module 140 </ b> C does not include the quarter wavelength line 400 as compared to the power amplification module 140 </ b> B, so the circuit area can be reduced.

  When the power amplification modules 140A to 140C perform a normal amplification operation, the peak amplifier 320 may be controlled to operate at the same operating point as the carrier amplifier 310 as described above, or is controlled to be in the off state. It is also good. When the peak amplifier 320 is controlled to the off state, only the carrier amplifier 310 performs an amplification operation of the RF signal RF1.

  Here, when the peak amplifier 320 is controlled to operate at the same operating point as the carrier amplifier 310 during the normal amplification operation, the saturated output power during the normal amplification operation of the power amplification modules 140A to 140C and the Doherty operation Saturated output power is equal. Therefore, the voltage Vreg output from the power supply module 130A is preferably controlled such that the maximum output voltage in the ET system is equal to the output voltage in the APT system.

  On the other hand, in the power amplification module 140B, when the peak amplifier 320 is controlled to be in the off state during the normal amplification operation, the saturated output power during the normal amplification operation is reduced by 6 dB compared to the saturated output power during the Doherty operation. Therefore, in order to obtain the same saturated output power in the normal amplification operation and the Doherty operation, the voltage Vreg output from the power supply module 130A is such that the maximum output voltage in the ET system is equal to twice the output voltage in the APT system Preferably, it is controlled.

  Further, in the power amplification module 140C, when the peak amplifier 320 is controlled to be in the off state during the normal amplification operation, the saturated output power during the normal amplification operation is reduced by 3 dB compared to the saturated output power during the Doherty operation. Therefore, in order to obtain the same saturated output power in the normal amplification operation and the Doherty operation, the voltage Vreg output from the power supply module 130A is equal to the maximum output voltage in the ET system √2 times the output voltage in the APT system It is preferable to control so that

  FIG. 6 is a view showing a configuration example of the power supply module 130. As shown in FIG. Power supply module 130B shown in FIG. 6 further includes capacitor C2 and switch circuit SW1 as compared to power supply module 130A shown in FIG. Among these components, components excluding the inductor L1 and the capacitor C2 are formed in, for example, the same power supply IC 131B.

  One end of the capacitor C 2 (second capacitor) is connected to the output of the back switching amplifier 201 via the inductor L 1, and the other end is connected to the output of the linear amplifier 220. The capacitance value of the capacitor C2 is, for example, about 1 μF to 10 μF.

  The switch circuit SW1 is provided between the connection point of the linear amplifier 220 and the capacitor C2 and the ground. The switch circuit SW1 is provided to switch the function of the capacitor C2 in accordance with the method of generating the power supply voltage. Specifically, when the power supply module 130B generates a power supply voltage according to the ET method, the switch circuit SW1 is turned off (see FIG. 6). At this time, the capacitor C2 has a coupling function of blocking the direct current component included in the output voltage of the linear amplifier 220 and passing the alternating current component. On the other hand, when the power supply module 130B generates a power supply voltage according to the APT method, the switch circuit SW1 is turned on, and the other end of the capacitor C2 is connected to the ground. At this time, the capacitor C2 has a decoupling function of releasing an AC component (for example, switching noise generated in the back switching amplifier 201) of a path from the power supply module 130B to the power amplification module 140 to the ground.

  Such a configuration of the power supply module 130 </ b> B may be applied to the power supply module 130 shown in FIG. 1. According to this configuration, one capacitor C2 can realize both coupling and decoupling functions.

  Next, each embodiment in the case where the generation method of the power supply voltage includes the discrete level ET method which is a modified example of the ET method in addition to the above-mentioned APT method and ET method will be described.

  FIG. 7 is a diagram showing a circuit configuration of a transmission unit 100B according to the second embodiment of the present invention.

  As shown in FIG. 7, the transmission unit 100B includes a power supply module 130C instead of the power supply module 130A as compared to the transmission unit 100A. The power supply module 130 </ b> C includes a multi-level back switching amplifier 202 instead of the back switching amplifier 201 as compared to the power supply module 130 </ b> A.

  Multi-level back switching amplifier 202 steps up or down power supply voltage Vbatt of a predetermined level, and outputs voltage Vreg discretely fluctuating with the fluctuation of the amplitude level of RF signal RFin.

  FIG. 8 is a diagram showing a configuration example of the multi-level back switching amplifier 202. As shown in FIG. As shown in the figure, the multi-level back switching amplifier 202 responds to, for example, four back switching amplifiers 203a to 203d, three switches 204a to 204c, and a control signal Ctrl1 (first control signal) supplied. And a driver IC 205 for switching on and off the three switches 204a to 204c.

  The four back switching amplifiers 203a to 203d respectively output voltages of 1/2, 1/4, 1/8 and 1/8 of the maximum output voltage of the multilevel back switching amplifier 202. The voltage Vreg which fluctuates discretely is generated by changing the combination of the voltages to be added among the voltages output from these four back switching amplifiers 203a to 203d. Of course, the multi-level back switching amplifier 202 can also output a constant voltage by keeping the on and off states of the three switches 204a to 204c constant. The number of back switching amplifiers 203a to 203d and the number of switches 204a to 204c are merely an example, and the present invention is not limited thereto.

  As described above, in the power supply module 130C according to the present embodiment, the power supply voltage continuously fluctuates with the fluctuation of the amplitude level of the RF signal, and the power supply voltage fluctuates discretely with the fluctuation of the amplitude level of the RF signal. A power supply voltage that fluctuates according to the average output power of the power amplification module 140A can be output. Note that, in the following, a system in which a voltage which discretely fluctuates with the fluctuation of the amplitude level of the RF signal is used as a power supply voltage is also referred to as a discrete level ET system.

FIG. 9 is an image diagram showing the relationship between the bandwidth and the power efficiency when the transmission unit 100B according to the second embodiment of the present invention operates in accordance with various schemes. The combinations of the power supply voltage generation method and the power amplification method shown in the figure are as shown in Table 2 below. In the graph shown in the figure, the horizontal axis indicates the bandwidth (MHz) of the RF signal, and the vertical axis indicates the power efficiency.

  As shown in FIG. 9 (4), according to the combination of the discrete level ET method and the normal amplification operation, the power efficiency in the region where the bandwidth is relatively narrow is inferior to the combination shown in FIG. 9 (3). , Higher than the combination shown in FIG. However, in the region where the bandwidth is relatively wide, the combination of the discrete level ET scheme and the normal amplification operation is less efficient than the combination shown in FIG. 9 (1).

  Further, according to the combination of the discrete level ET method and the Doherty operation shown in FIG. 9 (5), the efficiency is higher in any bandwidth as compared with the combination shown in FIG. 9 (4). Therefore, as described later, power can be amplified with high efficiency regardless of the bandwidth by appropriately selecting the combination of the power supply voltage generation method and the power amplification method, in which the efficiency increases according to the bandwidth. .

  Before describing the pattern combination of methods achieving high efficiency, FIG. 9 does not show the combination of ET method and Doherty operation, but shows the combination of discrete level ET method and Doherty operation The reason will be described with reference to FIGS. 10A and 10B.

  FIG. 10A is an image diagram showing a relationship between output power and power efficiency when the generation method of the power supply voltage is the ET method or the discrete level ET method and the power amplification method is the normal amplification operation. FIG. 10B is an image diagram showing the relationship between the output power and the power efficiency when the power supply voltage generation method is the ET method or the discrete level ET method and the power amplification method is the Doherty operation. The graphs in FIG. 10A and FIG. 10B show the respective power efficiencies when the power supply voltage is changed to five types.

  When the power supply voltage is generated according to the discrete level ET scheme, the power efficiency improves in the case of Doherty operation compared to the normal amplification operation. For example, comparing the power efficiency at the average output power ave, in the case of the discrete level ET method, by combining the Doherty operation, the power supply voltage reaches almost the same level as in the ET method regardless of the case (FIG. 10B) reference). On the other hand, when the power supply voltage is generated according to the ET scheme, relatively high efficiency is achieved even in the normal amplification operation (see FIG. 10A). Therefore, as understood from comparison of FIG. 10A and FIG. 10B, the ET method is less effective in combining the Doherty operation than the discrete level ET method. From the above, it is preferable to combine the Doherty operation with the discrete level ET method and the normal amplification operation with the ET method.

FIG. 11 is an image diagram showing the relationship between the bandwidth and the power efficiency in the operation pattern A that can be realized by the transmission unit 100B. The operation pattern A is a combination of the methods shown in Table 3 below.

  Operation pattern A combines the ET scheme and a normal amplification operation in a relatively narrow first bandwidth, combines the APT scheme and a Doherty operation in a relatively wide second bandwidth, and is wider than the first bandwidth than the second bandwidth It is a pattern which combines the discrete level ET method and the Doherty operation in the narrow third bandwidth. In the operation pattern A, the power supply module 130C requires the boost switching amplifier 200 and the multi-level back switching amplifier 202, and the power amplification module 140A requires the configuration of the Doherty amplifier, but in comparison with operation pattern B and operation pattern C described later There is an advantage that high efficiency can be realized over the entire bandwidth.

  FIG. 12 is a diagram showing a circuit configuration of a transmission unit 100C according to the third embodiment of the present invention.

  As shown in FIG. 12, the transmission unit 100C includes a power supply module 130D instead of the power supply module 130C as compared to the transmission unit 100B. The power supply module 130D does not include the boost switching amplifier 200, the differential amplifier 210, and the linear amplifier 220, as compared to the power supply module 130C. That is, the power supply module 130D has a configuration that can be applied when the power supply module 130D does not comply with the ET system. The multi-level back switching amplifier 202 is formed, for example, in the power supply IC 131D.

FIG. 13 is an image diagram showing the relationship between the bandwidth and the power efficiency in the operation pattern B that can be realized by the transmission unit 100C. The operation pattern B is a combination of the methods shown in Table 4 below.

  The operation pattern B is a pattern combining the discrete level ET method and the Doherty operation in a relatively narrow bandwidth and an intermediate bandwidth, and combining the APT method and the Doherty operation in a relatively wide bandwidth. In this case, the relatively narrow bandwidth and the middle bandwidth correspond to the first bandwidth, and the relatively wide bandwidth corresponds to the second bandwidth. The operation pattern B is slightly inferior in power efficiency in a region where the bandwidth is relatively narrow compared to the above-described operation pattern A, but has an advantage that the power supply module 130D does not require the boost switching amplifier 200 or the like.

  FIG. 14 is a diagram showing a circuit configuration of a transmission unit 100D according to the fourth embodiment of the present invention.

  As shown in FIG. 14, the transmission unit 100D includes a power amplification module 140D instead of the power amplification module 140A as compared to the transmission unit 100B. The power amplification module 140D does not include the peak amplifier 320, the divider 330, and the combiner 340, as compared to the power amplification module 140A. That is, the power amplification module 140D is configured to be applied when performing a normal amplification operation without performing the Doherty operation. Specifically, in the power amplification module 140D, the driver amplifier 300 amplifies the RF signal RFin and outputs an RF signal RFin '. The carrier amplifier 310 amplifies the RF signal RFin ′ and outputs an amplified signal RFout.

FIG. 15 is an image diagram showing the relationship between the bandwidth and the power efficiency in the operation pattern C that can be realized by the transmission unit 100D. The operation pattern C is a combination of methods shown in Table 5 below.

  The operation pattern C combines the ET scheme and the normal amplification operation in a relatively narrow bandwidth, combines the discrete level ET scheme and the normal amplification operation in the middle bandwidth, and the APT scheme and the normal amplification in a relatively wide bandwidth. It is a pattern that combines operations. In this case, the relatively narrow bandwidth and the middle bandwidth correspond to the first bandwidth, and the relatively wide bandwidth corresponds to the second bandwidth. The operation pattern C is slightly inferior in power efficiency in a relatively wide bandwidth to the above-described operation pattern A, but has an advantage that the power amplification module 140D does not require the configuration of the Doherty amplifier.

  As described above, in the transmission units 100B to 100D, by appropriately changing the combination of the generation method of the power supply voltage and the amplification method of the power according to the bandwidth of the RF signal RFin, the power can be high efficiency regardless of the bandwidth. It can be amplified. The combination of the generation method of the power supply voltage and the amplification method of the power in each embodiment described above is an example, and the combination is not limited to this. Further, the combination of the power supply modules 130A to 130D and the power amplification modules 140A to 140D is also not limited to this.

  For example, although the power amplification modules 140A to 140C described above include the configuration of the Doherty amplifier, when the transmission module does not perform the Doherty operation, the configuration of the power amplification module 140D that does not include the configuration of the Doherty amplifier may be applied.

  In each of the above-described embodiments, an example is shown in which the baseband unit 110 outputs the control signals Ctrl1 and Ctrl2 and the envelope signal Env. However, instead of the baseband unit 110, the RF unit 120 has the amplitude of the modulation signal. A level may be detected to output control signals Ctrl1 and Ctrl2 and an envelope signal Env.

  The exemplary embodiments of the present invention have been described above. The transmission units 100 and 100A to 100D amplify the power of the input signal (RF signal RFin ') and output the amplified signal RFout, and the first control signal based on the bandwidth of the input signal. The power supply modules 130 and 130A to 130D for supplying a power supply voltage to the power amplification module, wherein the power supply modules 130 and 130A to 130D have a first bandwidth of the input signal based on the first control signal. In this case, the power supply voltage is changed according to the amplitude level of the input signal, and when the bandwidth of the input signal is a second bandwidth wider than the first bandwidth, the power supply voltage is varied according to the average output power of the power amplification module Let Thus, in the transmission units 100 and 100A to 100D, when the bandwidth of the RF signal is relatively narrow, the ET scheme is followed, and when the bandwidth is relatively wide, the APT scheme is followed. Therefore, for example, power efficiency can be improved regardless of the width of the bandwidth as compared with the configuration that always follows the ET scheme.

  Also, the power amplification modules 140A to 140C divide the input signal into the RF signal RF1 and the RF signal RF2, the carrier amplifier 310 that amplifies the RF signal RF1 and outputs the RF signal RF3, and the RF signal RF2 Are amplified and the RF signal RF4 is output, the RF signal RF3 and the RF signal RF4 are combined, and the synthesizer 340 which outputs the amplified signal RFout, and the bias current or the current for each of the carrier amplifier 310 and the peak amplifier 320. A bias circuit 350 for supplying a bias voltage, and when the bandwidth of the input signal is the second bandwidth based on the second control signal, the carrier amplifier 310 performs the class A operation or the class AB. Operation, and bias current or bias voltage so that peak amplifier 320 becomes class C operation. To integer. Thereby, in the transmission units 100A to 100C, when the bandwidth is wide, the power amplification modules 140A to 140C perform the Doherty operation. Therefore, the power efficiency can be further improved as compared with the configuration in which the normal amplification operation is performed regardless of the bandwidth.

  In power amplification modules 140A to 140C, based on the second control signal, bias circuit 350 operates at an operating point where carrier amplifier 310 and peak amplifier 320 are equal when the bandwidth of the input signal is the first bandwidth. The bias current or bias voltage may be adjusted to Thus, both of the normal amplification operation and the Doherty operation can be performed by one power amplification module 140A to 140C. Therefore, it is possible to suppress an increase in circuit area as compared with a configuration in which different power amplification modules are provided for each power amplification method. Also, during the normal amplification operation, both the carrier amplifier 310 and the peak amplifier 320 are in the operating state. Therefore, at the time of normal amplification operation, it is possible to obtain the same level of saturated output power as at the time of Doherty operation.

  Further, in the power amplification modules 140A to 140C, the bias circuit 350 sets the bias current or the bias current so that the peak amplifier 320 is turned off when the bandwidth of the input signal is the first bandwidth based on the second control signal. The bias voltage may be adjusted.

  Further, the combiner 340A combines a combining unit 410 combining the RF signal RF3 and the RF signal RF4, and a quarter wavelength line 400 connected in series between the output of the carrier amplifier 310 and the combining unit 410. Including. Thus, when the phase of the RF signal RF1 is advanced approximately 90 degrees from the phase of the RF signal RF2 in the divider 330, the phase difference between the RF signal RF3 and the RF signal RF4 is approximately 0 degree in the combining unit 410 and is combined. Ru.

  In addition, the combiner 340 B combines the RF signal RF 3 and the RF signal RF 4, the inductor L 2 serially connected between the output of the carrier amplifier 310 and the combiner 410, the peak amplifier 320 and the combiner The inductor L2 delays the phase of the RF signal RF3 by about 45 degrees, and the capacitor C1 advances the phase of the RF signal RF4 by about 45 degrees. Thus, when the phase of the RF signal RF1 is advanced by about 45 degrees in the divider 330 and the phase of the RF signal RF2 is delayed by about 45 degrees, the phase difference between the RF signal RF3 and the RF signal RF4 is about 0 in the combining unit 410. And it is synthesized.

  Also, the power supply module 130 B is connected to the output of the back switching amplifier 201 at one end, with the back switching amplifier 201 that steps up or down the power supply voltage Vbatt, the linear amplifier 220 that outputs the voltage Vreg according to the amplitude level of the input signal. The capacitor C2 has the other end connected to the output of the linear amplifier 220, and the switch circuit SW1 connects the other end of the capacitor C2 to the ground when the bandwidth of the input signal is the second bandwidth. Thereby, one capacitor C2 can realize both coupling and decoupling functions.

  In addition, when the bandwidth of the input signal is the first bandwidth based on the first control signal, the power supply module 130C continuously varies the power supply voltage with the variation of the amplitude level of the input signal, thereby the input signal The power supply voltage may be discretely fluctuated along with the fluctuation of the amplitude level of the input signal, when the third bandwidth is wider than the first bandwidth and narrower than the second bandwidth. Thereby, the power efficiency in the third bandwidth can be further improved compared to the transmission unit 100A.

  In transmission unit 100B, based on the second control signal, bias circuit 350 generates a carrier amplifier when the bandwidth of the input signal is the second bandwidth and when the bandwidth of the input signal is the third bandwidth. Is a class A operation or a class AB operation, and the bias current or the bias voltage may be adjusted so that the peak amplifier becomes a class C operation. Thereby, power efficiency in the second bandwidth and the third bandwidth can be improved as compared to the case of performing a normal amplification operation.

  Further, when the bandwidth of the input signal is the first bandwidth based on the first control signal, the power supply module 130D may vary the power supply voltage discretely along with the variation of the amplitude level of the input signal. . Thereby, the power supply voltage can be generated according to the discrete level ET scheme in the first bandwidth.

  Further, in transmission unit 100C, based on the second control signal, bias circuit 350 generates a carrier amplifier when the bandwidth of the input signal is the first bandwidth and when the bandwidth of the input signal is the second bandwidth. Is a class A operation or a class AB operation, and the bias current or the bias voltage may be adjusted so that the peak amplifier becomes a class C operation. Thereby, power efficiency in the first bandwidth and the second bandwidth can be improved as compared to the case of performing a normal amplification operation.

  Each embodiment described above is for facilitating the understanding of the present invention, and is not for limiting and interpreting the present invention. The present invention can be modified or improved without departing from the gist thereof, and the present invention also includes the equivalents thereof. That is, those in which persons skilled in the art appropriately modify the design of each embodiment are also included in the scope of the present invention as long as they have the features of the present invention. For example, each element included in each embodiment and its arrangement, material, conditions, shape, size, and the like are not limited to those illustrated, and may be changed as appropriate. Further, the elements included in each embodiment can be combined as much as technically possible, and combinations of these are included in the scope of the present invention as long as they include the features of the present invention.

100, 100A to 100D ... Transmission unit, 110 ... Base band section, 120 ... RF section, 130, 130A to 130D ... Power supply module, 131A to 131D ... Power supply IC, 140, 140A to 140D ... Power amplification module, 150 ... Front end Part, 160 ... antenna, 200 ... boost switching amplifier, 201 ... back switching amplifier, 202 ... multi-level back switching amplifier, 203a-203d ... back switching amplifier, 204a-204c ... switch, 205 ... driver IC, 210 ... differential amplifier , 220: linear amplifier, 300: driver amplifier, 310: carrier amplifier, 320: peak amplifier, 330: distributor, 340, 340A, 340B: synthesizer, 350: bias circuit, 400: quarter wave Line, 410 ... synthesis unit, L1, L2 ... inductors, C1, C2 ... capacitor, SW1 ... switching circuit

Claims (11)

A power amplification module that amplifies the power of an input signal and outputs an amplified signal;
A power supply module for supplying a power supply voltage to the power amplification module based on a first control signal according to a bandwidth of the input signal;
Equipped with
The power supply module is configured to receive the first control signal.
If the bandwidth of the input signal is a first bandwidth, the power supply voltage is varied according to the amplitude level of the input signal,
If the bandwidth of the input signal is a second bandwidth wider than the first bandwidth, the power supply voltage is varied according to the average output power of the power amplification module.
Transmission unit. The power amplification module is
A divider for dividing the input signal into a first signal and a second signal;
A carrier amplifier for amplifying the first signal and outputting a third signal;
A peak amplifier for amplifying the second signal and outputting a fourth signal;
A combiner that combines the third signal and the fourth signal and outputs the amplified signal;
A bias circuit for supplying a bias current or a bias voltage to each of the carrier amplifier and the peak amplifier based on a second control signal corresponding to a bandwidth of the input signal;
Equipped with
When the bandwidth of the input signal is the second bandwidth based on the second control signal, the bias circuit performs the class A operation or the class AB operation of the carrier amplifier, and the peak amplifier performs a class C operation. Adjust the bias current or bias voltage to be
The transmission unit according to claim 1. When the bandwidth of the input signal is the first bandwidth based on the second control signal, the bias circuit operates the bias current or the bias current such that the carrier amplifier and the peak amplifier operate at the same operating point. Adjust the bias voltage,
The transmission unit according to claim 2. The bias circuit adjusts the bias current or the bias voltage based on the second control signal such that the peak amplifier is turned off when the bandwidth of the input signal is the first bandwidth.
The transmission unit according to claim 2. The synthesizer is
A combining unit that combines the third signal and the fourth signal;
A quarter wavelength line connected in series between the output of the carrier amplifier and the combining unit;
including,
The transmission unit according to any one of claims 2 to 4. The synthesizer is
A combining unit that combines the third signal and the fourth signal;
An inductor connected in series between the output of the carrier amplifier and the combining unit;
A first capacitor connected in series between the peak amplifier and the combining unit;
Including
The inductor delays the phase of the third signal by about 45 degrees, and the first capacitor advances the phase of the fourth signal by about 45 degrees.
The transmission unit according to any one of claims 2 to 4. The power supply module is
A switching amplifier that steps up or down a predetermined voltage;
A linear amplifier that outputs the power supply voltage according to the amplitude level of the input signal;
A second capacitor having one end connected to the output of the switching amplifier and the other end connected to the output of the linear amplifier;
A switch circuit that connects the other end of the second capacitor to the ground when the bandwidth of the input signal is the second bandwidth;
Equipped with
The transmission unit according to any one of claims 1 to 6. The power supply module is configured to receive the first control signal.
When the bandwidth of the input signal is the first bandwidth, the power supply voltage is continuously varied according to the variation of the amplitude level of the input signal,
When the bandwidth of the input signal is a third bandwidth which is wider than the first bandwidth and narrower than the second bandwidth, the power supply voltage is discretely fluctuated according to the fluctuation of the amplitude level of the input signal.
The transmission unit according to claim 1. The power amplification module is
A divider for dividing the input signal into a first signal and a second signal;
A carrier amplifier for amplifying the first signal and outputting a third signal;
A peak amplifier for amplifying the second signal and outputting a fourth signal;
A combiner that combines the third signal and the fourth signal and outputs the amplified signal;
A bias circuit for supplying a bias current or a bias voltage to each of the carrier amplifier and the peak amplifier based on a second control signal corresponding to a bandwidth of the input signal;
Equipped with
The bias circuit is configured to generate the second control signal based on the second control signal.
When the bandwidth of the input signal is the second bandwidth and when the bandwidth of the input signal is the third bandwidth, the carrier amplifier is in class A operation or class AB operation, and the peak amplifier is C Adjusting the bias current or bias voltage to achieve a class operation
The transmission unit according to claim 8. The power supply module discretely varies the power supply voltage according to the fluctuation of the amplitude level of the input signal when the bandwidth of the input signal is the first bandwidth based on the first control signal. ,
The transmission unit according to claim 1. The power amplification module is
A divider for dividing the input signal into a first signal and a second signal;
A carrier amplifier for amplifying the first signal and outputting a third signal;
A peak amplifier for amplifying the second signal and outputting a fourth signal;
A combiner that combines the third signal and the fourth signal and outputs the amplified signal;
A bias circuit for supplying a bias current or a bias voltage to each of the carrier amplifier and the peak amplifier based on a second control signal corresponding to a bandwidth of the input signal;
Equipped with
The bias circuit is configured such that, based on the second control signal, when the bandwidth of the input signal is the first bandwidth and when the bandwidth of the input signal is the second bandwidth, the carrier amplifier The bias current or bias voltage is adjusted such that the class A operation or the class AB operation is performed, and the peak amplifier becomes a class C operation.
The transmission unit according to claim 10.