Portable device, load modulation power amplifier system, and method of amplification in a portable device - Patents.com

Abstract

To provide load modulated power amplifiers and methods that can provide high efficiency over a wide dynamic range.SOLUTION: A load modulated power amplifier 10 includes: a power amplifier 5 that receives a radio frequency signal (RF input signal RFIN) at a reception input and provides an amplified radio frequency signal at an output; and a controllable load impedance 6 coupled to the output of the power amplifier 5. The controllable load impedance receives an envelope signal ENV that changes in relation to an envelope of the radio frequency signal. The envelope signal is operable to control an impedance of the controllable load impedance to modulate a load at the output of the power amplifier.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] Embodiments of the present invention relate to electronic systems, and more specifically to radio frequency (RF) electronic equipment. [Background technology]

[0002] In RF communication systems, power amplifiers are used to amplify RF signals for transmission via antennas.

[0003] Examples of RF communication systems having one or more power amplifiers include, but are not limited to, mobile phones, tablets, base stations, network access points, customer premises equipment (CPE), laptops, and wearable electronic devices. For example, in wireless devices communicating using cellular standards, wireless local area network (WLAN) standards, and / or any other suitable communication standards, power amplifiers can be used for the purpose of amplifying RF signals. RF signals may have frequencies in the range of approximately 400 MHz to approximately 7.125 GHz for frequency range 1 (FR1) of the fifth-generation (5G) communication standard, or in the range of approximately 24.250 GHz to approximately 71.000 GHz for frequency range 2 (FR2) of the 5G communication standard, for example, in the range of approximately 30 kHz to 300 GHz. [Overview of the Initiative]

[0004] In a given embodiment, this disclosure relates to a portable device. The portable device includes a transceiver configured to generate a radio frequency signal and an envelope signal that changes in relation to the envelope of the radio frequency signal, and a front-end system including a load-modulated power amplifier configured to amplify the radio frequency signal. The load-modulated power amplifier includes a power amplifier configured to receive the radio frequency signal at an input and provide an amplified radio frequency signal at an output, and a controllable load impedance coupled to the output of the power amplifier. The envelope signal is operable to modulate a load at the output of the power amplifier by controlling the impedance of the controllable load impedance.

[0005] In various embodiments, the transceiver includes a shaping circuit configured to shape the envelope signal based on calibration data. According to certain embodiments, the shaping circuit can be operated to provide a flat gain-to-input power characteristic to the power amplifier.

[0006] In some embodiments, the controllable load impedance includes a controllable capacitor controlled by an envelope signal, and an output balun having a first winding coupled to the output of a power amplifier, and a second winding coupled to the controllable capacitor. According to some embodiments, the power amplifier includes an input balun and a pair of amplifiers coupled between the input balun and the output balun. According to various embodiments, the second winding includes a first terminal that outputs an amplified radio frequency signal and a second terminal coupled to the controllable capacitor. According to some embodiments, the controllable capacitor includes a bipolar transistor and a load capacitor coupled to the collector of the bipolar transistor, and the envelope signal is operable to control the base of the bipolar transistor. According to some embodiments, the controllable load impedance includes a series coupling of an inductor and a controllable capacitor having a capacitance controlled by an envelope signal.

[0007] In various embodiments, the portable device further includes an antenna capable of transmitting amplified radio frequency signals.

[0008] In a given embodiment, the disclosure relates to a load-modulated power amplifier system. The load-modulated power amplifier system includes a power amplifier configured to receive a radio frequency signal at an input and to provide an amplified radio frequency signal at an output. The load-modulated power amplifier system further includes a controllable load impedance coupled to the output of the power amplifier, the controllable load impedance configured to receive an envelope signal that changes in relation to the envelope of the radio frequency signal. The envelope signal is operable to modulate the load at the output of the power amplifier by controlling the impedance of the controllable load impedance.

[0009] In some embodiments, the controllable load impedance includes a controllable capacitor controlled by an envelope signal, and an output balun having a first winding coupled to the output of a power amplifier and a second winding coupled to the controllable capacitor. According to some embodiments, the power amplifier includes an input balun and a pair of amplifiers coupled between the input balun and the output balun. According to various embodiments, the second winding includes a first terminal that outputs an amplified radio frequency signal and a second terminal coupled to the controllable capacitor. According to some embodiments, the controllable capacitor includes a bipolar transistor and a load capacitor coupled to the collector of the bipolar transistor, and the envelope signal is operable to control the base of the bipolar transistor.

[0010] In various embodiments, the controllable load impedance includes a series connection of an inductor and a controllable capacitor having a capacitance controlled by an envelope signal.

[0011] In a given embodiment, the disclosure relates to a method of amplification in a portable device. The method includes generating a radio frequency signal and an envelope signal that changes in relation to the envelope of the radio frequency signal using a transceiver. The method further includes amplifying the radio frequency signal using a power amplifier, which includes receiving the radio frequency signal at the input of the power amplifier and providing the amplified radio frequency signal at the output of the power amplifier. The method further includes modulating the load of the power amplifier using the envelope signal to control the impedance of a controllable load impedance coupled to the output of the power amplifier.

[0012] In various embodiments, the method further includes calibrating the power amplifier by shaping the envelope signal based on calibration data. According to certain embodiments, calibrating the power amplifier includes providing a flat gain-to-input power characteristic.

[0013] In some embodiments, modulating the load of a power amplifier includes controlling the capacitance of a controllable capacitor coupled to an output balun. According to certain embodiments, the method further includes supplying an amplified radio frequency signal to a first winding of the output balun, the controllable capacitor being coupled to a second winding of the output balun. [Brief explanation of the drawing]

[0014] Embodiments of the present disclosure are described below through non-limiting examples with reference to the accompanying drawings.

[0015] [Figure 1] This is a schematic diagram of a load-modulated power amplifier according to one embodiment. [Figure 2] This is a schematic diagram of a load-modulated power amplifier according to another embodiment. [Figure 3] This is a schematic diagram of a load-modulated power amplifier system according to one embodiment. [Figure 4A] This is a schematic diagram of a load-modulated power amplifier system according to another embodiment. [Figure 4B] This is a schematic diagram of a load-modulated power amplifier system according to another embodiment. [Figure 5A] This is a schematic diagram of a controllable capacitor in one embodiment for a load-modulated power amplifier. [Figure 5B] This is a schematic diagram of a controllable capacitor in one embodiment for a load-modulated power amplifier. [Figure 6] This is an example of a Smith chart of collector impedance versus control voltage for a load-modulated power amplifier. [Figure 7] This is an example graph of a gain versus output power plot for a load-modulated power amplifier. [Figure 8] This is an example graph of a power added efficiency (PAE) versus output power plot for a load-modulated power amplifier. [Figure 9] This is an example graph of a gain versus output power plot for a load-modulated power amplifier. [Figure 10]It is a graph of another example of a PAE vs. output power plot for a load modulation power amplifier. [Figure 11] It is a schematic diagram of a mobile device according to an embodiment. [Figure 12A] It is a schematic diagram of a package module according to an embodiment. [Figure 12B] It is a schematic diagram of a cross-section of a package module along line 12B-12B of FIG. 12A. [Figure 13] It is a schematic diagram of an embodiment of a communication system that transmits RF signals. **DETAILED DESCRIPTION OF THE INVENTION**

[0016] The following detailed description of certain embodiments presents various descriptions of specific embodiments. However, the innovations described herein can be embodied in many different ways, for example, as defined and covered by the claims. In this specification, drawings are referred to in which the same reference numbers indicate identical or functionally similar elements. It is understood that the elements shown in the drawings are not necessarily to scale. It is further understood that certain embodiments may include more elements than shown in the drawings and / or a subset of the elements shown in the drawings. Additionally, some embodiments may include any suitable combination of features from two or more of the drawings.

[0017] A load modulation power amplifier is provided herein. In certain embodiments, the load modulation power amplifier includes a power amplifier that amplifies a radio frequency (RF) input signal and a load impedance coupled to the output of the power amplifier. The load impedance is controlled based on the envelope of the RF input signal to provide load modulation to the output of the power amplifier. By providing load impedance modulation in this manner, high efficiency is obtained over a wide dynamic range.

[0018] In a given implementation example, the load impedance includes an output balun, which includes a first winding and a second winding that are electromagnetically coupled to each other. Additionally, the output of a power amplifier is coupled to the first terminal of the first winding (or configured in a push-pull configuration where the output is coupled to two terminals of the first winding), while the amplified RF signal is output from the first terminal of the second winding. The load impedance further includes a controllable capacitor coupled to the second terminal of the second winding. This controllable capacitor has a capacitance controlled by the envelope of the RF signal.

[0019] In other words, load modulation can be performed by sweeping the impedance of the termination capacitor at the secondary port of the balun. In a given implementation example, the termination capacitor is controlled by an analog envelope control signal from the transceiver, which can be calibrated by achieving a desired gain and / or efficiency characteristic, such as isogain.

[0020] In a given implementation example, the load impedance includes a heterojunction bipolar transistor (HBT) switch having a capacitor-coupled collector and a base controlled by an envelope signal. Additionally, the HBT switch operates as a variable resistor having a highest load line achieved when the switch is open and a lowest load line achieved at the highest envelope voltage level when the switch is closed. In such a configuration, the lowest loss is achieved at the highest load line, which is beneficial for modulated efficiency of high peak-to-average power ratio (PAPR) waveforms, such as those used in 5G communications.

[0021] Compared to a power amplifier where an envelope tracker controls the power amplifier's supply voltage based on the envelope signal, a load-modulated power amplifier has a load impedance that is controlled based on the envelope signal. By applying load modulation in this manner, a highly efficient power amplifier can be obtained that is less complex than an envelope tracker amplifier while utilizing a circuit that generates and calibrates the envelope signal for the purpose of achieving the desired performance.

[0022] For example, a load-modulated power amplifier can be powered by a highly efficient DC / DC converter, such as a power management unit (PMU) operating at an efficiency of 93% or more. Such a PMU can operate using average power tracking (APT) over 5.5V + 2.5~3.0V (where the power amplifier efficiency can be good at higher supply voltages due to the non-zero knee voltage). In contrast, an envelope tracking system has an efficiency of only about 80% at supply voltages of approximately 2.5~3.0V (where the power amplifier efficiency can be poor at lower supply voltages due to the non-zero knee voltage). The PMU is also referred to here as a power management integrated circuit (PMIC).

[0023] Load-modulated power amplifiers may be included in a wide variety of RF communication systems, including but not limited to base stations, network access points, mobile phones, tablets, customer premises equipment (CPE), laptops, computers, wearable electronic devices, and / or other communication devices.

[0024] Figure 1 is a schematic diagram of a load-modulated power amplifier 10 according to one embodiment. The load-modulated power amplifier 10 includes a power amplifier 5 and a controllable load impedance 6. The load-modulated power amplifier 10 receives an RF input signal RF IN The RF output signal is amplified. OUT Generates.

[0025] The load-modulated power amplifier 10 receives the RF input signal RF IN An envelope signal ENV is received that changes in relation to the envelope. The envelope signal ENV is used to control the impedance of the controllable load impedance 6. For example, in this embodiment, the controllable load impedance 6 includes a series connection of an inductor 8 and a controllable capacitor 7, and the envelope signal ENV is used to control the capacitance of the controllable capacitor 7. Although an example of a controllable load impedance is depicted, the teachings herein are applicable to other implementations of the controllable load impedance.

[0026] Figure 2 is a schematic diagram of a load-modulated power amplifier 20 in another embodiment. The load-modulated power amplifier 20 in Figure 2 is similar to the load-modulated power amplifier 10 in Figure 1, but differs in that the load-modulated power amplifier 20 in Figure 2 includes a controllable load impedance 16 with a different implementation.

[0027] More specifically, the controllable load impedance 16 includes the balun 18 and the controllable capacitor 7. The output of the power amplifier 5 drives the first winding of the balun 18. Additionally, the first terminal of the second winding of the balun 18 receives the RF output signal RF OUT While outputting this signal, the second terminal of the second winding is coupled to a controllable capacitor 7. The controllable capacitor 7 is controlled by the envelope signal ENV.

[0028] By changing the value of the controllable capacitor 7, a portion of the inductance of the second winding resonates effectively, thereby effectively changing the turns ratio of the balun 18.

[0029] Figure 3 is a schematic diagram of a load-modulated power amplifier system 40 according to one embodiment. The load-modulated power amplifier system 40 includes a load-modulated power amplifier 25, a band-switching and tuning circuit 26, and an antenna 3.

[0030] In the illustrated embodiment, the load-modulated power amplifier 25 includes a driver amplifier 31, an input balun 32, a first output amplifier 33, a second output amplifier 34, and a controllable load impedance 16 including an output balun 18 and a controllable capacitor 7.

[0031] In this embodiment, the load-modulated power amplifier 25 is implemented as a push-pull amplifier. Additionally, the output of the first output amplifier 33 is connected to the first terminal of the first winding of the balun 18, while the output of the second output amplifier 34 is connected to the second terminal of the first winding of the balun 18.

[0032] Figure 4A is a schematic diagram of a load-modulated power amplifier system 110 of another embodiment. The load-modulated power amplifier system 110 includes an output balun 18, a power amplifier die 101, a switch die 102, an envelope generator die 103, and a driver die 104. The power amplifier die 101 includes a driver amplifier 31, an input balun 32, a first output amplifier 33, a second output amplifier 34, and a controllable capacitor 7. The switch die 102 includes a capacitor 107 and a switch 108. Furthermore, the envelope generator die 103 supplies a differential envelope signal ENV to the driver die 104. DIFF It includes a shaping circuit 105 that shapes the differential envelope signal ENV. The driver die 104 processes the differential envelope signal ENV. DIFF It includes an amplifier 106 that receives the signal. This amplifier outputs an envelope control signal ENV that controls the controllable capacitor 7.

[0033] The load-modulated power amplifier system 110 can be operated by system-level calibration, which matches and shapes the envelope control signal for the controllable capacitor 7 with respect to the RF input signal amplified by the push-pull amplifier.

[0034] Figure 4B is a schematic diagram of a load-modulated power amplifier system 120 of another embodiment. The load-modulated power amplifier system 120 includes an output balun 18, a power amplifier die 111, a switch die 112, an envelope generator die 103, and a driver die 104.

[0035] The load-modulated power amplifier system 120 in Figure 4B is similar to the load-modulated power amplifier system 110 in Figure 4A, but differs in that the load-modulated power amplifier system 120 shows an implementation example in which the controllable capacitor 7 is located on the switch die 112. Since the switch die 112 is typically implemented using a silicon-on-insulator (SOI) process and the power amplifier die 111 is implemented using a compound semiconductor process (e.g., GaAs), placing the controllable capacitor 7 on the switch die 112 helps to obtain a capacitor with a high quality factor (Q value).

[0036] Figure 5A is a schematic diagram of a controllable capacitor 210 of one embodiment for a load-modulated power amplifier. The controllable capacitor 210 includes a bipolar transistor 201 (e.g., a heterojunction bipolar transistor i.e., an HBT), a base resistor 202, a base capacitor 203, and a load capacitor 204. The base of the bipolar transistor 201 is controlled by an envelope signal ENV (received from an envelope tracer via the base resistor 202), while the emitter of the bipolar transistor 201 is grounded. The load capacitor 204 is coupled between the collector of the bipolar transistor 201 and the load terminal LD ​​that loads the power amplifier (e.g., by acting as a termination capacitor for an output balun driven by the power amplifier). The base capacitor 203 is connected between the base of the bipolar transistor 201 and ground.

[0037] The bipolar transistor 201 operates as a variable resistor with a highest load line achieved when the envelope signal ENV is low, and a lowest load line achieved when the envelope signal ENV is high. Lowest loss is achieved at the highest load line. This is beneficial for the modified efficiency of high PAPR waveforms.

[0038] Figure 5B is a schematic diagram of a controllable capacitor 220 of one embodiment for a load-modulated power amplifier. The controllable capacitor 220 includes a plurality of controllable capacitor cells 211a, 211b, 211c, ..., 211n connected in parallel to each other between the load terminal LD ​​(which loads the power amplifier) ​​and ground.

[0039] As shown in Figure 5B, the controllable capacitor cell 211a includes a bipolar transistor 201a, a base resistor 202a, a base capacitor 203a, a load capacitor 204a, a clamp diode 205a, and a clamp resistor 206a. The base of the bipolar transistor 201a is controlled by an envelope signal ENV received via the base resistor 202a, while the emitter of the bipolar transistor 201a is grounded. The load capacitor 204a is coupled between the collector of the bipolar transistor 201a and the load terminal LD. The base capacitor 203a is connected between the base of the bipolar transistor 201a and ground. Additionally, the clamp diode 205a and clamp resistor 206a are connected in series between the base of the bipolar transistor 201a and ground. Capacitor 203a is in parallel with the series coupling of the clamp diode 205a and clamp resistor 206a.

[0040] Continuing to refer to Figure 5B, the controllable capacitor cell 211b includes a bipolar transistor 201b, a base resistor 202b, a base capacitor 203b, a load capacitor 204b, a clamp diode 205b, a clamp resistor 206b, a diode bias resistor 207b, and a Schottky diode 208b1. Additionally, the controllable capacitor cell 211c includes a bipolar transistor 201c, a base resistor 202c, a base capacitor 203c, a load capacitor 204c, a clamp diode 205c, a clamp resistor 206c, a diode bias resistor 207c, and Schottky diodes 208c1 and 208c2. Furthermore, the controllable capacitor cell 211n includes a bipolar transistor 201n, a base resistor 202n, a base capacitor 203n, a load capacitor 204n, a clamp diode 205n, a clamp resistor 206n, a diode bias resistor 207n, and Schottky diodes 208n1, 208n2, ..., 208nm.

[0041] Although four controllable capacitor cells are depicted, any number of controllable capacitor cells may be included. As shown in Figure 5B, each additional controllable capacitor cell includes an additional Schottky diode compared to the preceding controllable capacitor.

[0042] Figure 6 shows an example of a Smith chart of collector impedance versus control voltage for a load-modulated power amplifier. In this example, a change of more than 2x (double) in the load impedance is achieved when the envelope control voltage (VCTRL) changes from 0.7V to 2.1V.

[0043] Figure 7 is a graph of an example of a gain versus output power plot for a load-modulated power amplifier.

[0044] Figure 8 is a graph of an example of a power added efficiency (PAE) versus output power plot for a load-modulated power amplifier.

[0045] Referring to Figures 7 and 8, the graphs illustrate one implementation example of a two-stage push-pull power amplifier with a balun loss of 0.3 dB.

[0046] The waterfall curve is plotted with exemplary values ​​shown to achieve isogain using envelope calibration (for example, by selecting shaping values ​​in an envelope shaping circuit).

[0047] Figure 9 is a graph of an example of a gain versus output power plot for a load-modulated power amplifier.

[0048] Figure 10 is a graph of another example of a PAE vs. output power plot for a load-modulated power amplifier.

[0049] Referring to Figures 9 and 10, in this example, an extremely flat PAE is achieved over a dynamic range of 6 dB.

[0050] Figure 11 is a schematic diagram of a portable device 800 according to one embodiment. The portable device 800 includes a baseband system 801, a transceiver 802, a front-end system 803, an antenna 804, a power management system 805, a memory 806, a user interface 807, and a battery 808.

[0051] The mobile device 800 can be used to communicate using a wide variety of communication technologies, including but not limited to 2G, 3G, 4G (LTE, LTE Advanced, and LTE Advanced Pro), 5G NR, WLAN (e.g., WiFi), WPAN (e.g., Bluetooth® and ZigBee®), WMAN (e.g., WiMAX), and / or GPS technology.

[0052] The transceiver 802 generates an RF signal for transmission and processes the incoming RF signal received from the antenna 804. It is understood that the various functions associated with transmitting and receiving RF signals can be achieved by one or more components, collectively represented as the transceiver 802 in Figure 11. In one example, a separate component (e.g., a separate circuit or die) may be provided to handle a predetermined type of RF signal.

[0053] The front-end system 803 assists in conditioning the signals transmitted to and / or received from antenna 804. In the illustrated embodiment, the front-end system 803 includes an antenna tuning circuit 810, a plurality of power amplifiers (PAs) 801, a plurality of low-noise amplifiers (LNAs) 812, a plurality of filters 813, a plurality of switches 814, and a signal splitting / coupling circuit 815. However, other implementation examples are also possible.

[0054] For example, the front-end system 803 can provide a certain number of functions, including, but not limited to, amplification of the transmit signal, amplification of the receive signal, filtering of the signal, switching between different bands, switching between different power modes, switching between the transmit mode and the receive mode, duplexing of the signal, multiplexing of the signal (e.g., diplexing or triplexing), or any combination thereof.

[0055] At least one of the multiple power amplifiers 811 is implemented as a load-modulated power amplifier as taught herein. Although the portable device 800 demonstrates one embodiment of a communication system in which one or more load-modulated power amplifiers may be implemented, the teaching herein is applicable to a wide range of systems. Therefore, other implementation examples are also possible.

[0056] In a given implementation example, the portable device 800 supports carrier aggregation, providing flexibility to increase the peak data rate. Carrier aggregation can be used with both frequency-division duplexing (FDD) and time-division duplexing (TDD), and may be used to aggregate multiple carriers or channels. Carrier aggregation includes continuous aggregation, where continuous carriers are aggregated within the same operating frequency band. Carrier aggregation may be discontinuous and may include carriers whose frequencies are separated within a common band or different bands.

[0057] The multiple antennas 804 may include antennas used for a wide variety of types of communication. For example, antennas 804 may include antennas for transmitting and / or receiving signals associated with a wide variety of frequencies and communication standards.

[0058] In a given implementation example, antenna 804 supports MIMO communication and / or switched diversity communication. For example, MIMO communication uses multiple antennas to communicate multiplexed data streams over a single radio frequency channel. MIMO communication benefits from a high signal-to-noise ratio, improved coding, and / or reduced signal interference due to the spatial multiplexing of the radio environment. Switched diversity refers to communication in which a specific antenna is selected to operate at a particular time. For example, a switch can be used to select a specific antenna from a group of antennas based on various factors such as the observed bit error rate and / or signal strength index.

[0059] The portable device 800 may operate with beamforming in a given implementation. For example, the front-end system 803 may include an amplifier with controllable gain and a phase shifter with controllable phase to provide beamforming and directivity for transmitting and / or receiving signals using antenna 804. For example, in the context of signal transmission, the amplitude and phase of the transmit signal supplied to antenna 804 are controlled so that the signal radiated from antenna 804 is coupled using constructive and destructive interference, resulting in an aggregated transmit signal exhibiting beam-like quality with strong signal intensity propagating in a given direction. In the context of signal reception, the amplitude and phase are controlled so that more signal energy is received when the signal arrives at antenna 804 from a particular direction. In a given implementation, antenna 804 includes one or more arrays of antenna elements to enhance beamforming.

[0060] The baseband system 801 is coupled to a user interface 807 that facilitates the processing of various user input / output (I / O) such as voice and data. The baseband system 801 provides a digital representation of the transmit signal to the transceiver 802, which processes this to generate the RF signal for transmission. The baseband system 801 also processes the digital representation of the receive signal provided by the transceiver 802. As shown in Figure 11, the baseband system 801 is coupled to a memory 806 to facilitate the operation of the portable device 800.

[0061] Memory 806 can be used for a wide variety of purposes, such as storing data and / or instructions, in order to facilitate the operation of the portable device 800 and / or to provide storage for user information.

[0062] The power management system 805 provides a certain number of power management functions for the portable device 800. In a given implementation example, the power management system 805 includes a PA supply control circuit that controls the supply voltage of a plurality of power amplifiers 811. For example, the power management system 805 may be configured to change the supply voltage supplied to one or more of the plurality of power amplifiers 811 in order to improve an efficiency such as power added efficiency (PAE).

[0063] As shown in Figure 11, the power management system 805 receives the battery voltage from the battery 808. The battery 808 may be any suitable battery for use in the portable device 800, including, for example, a lithium-ion battery.

[0064] Figure 12A is a schematic diagram of a package module 900 according to one embodiment. Figure 12B is a schematic diagram of a cross-section of the package module 900 along the line 12B-12B in Figure 12A.

[0065] The package module 900 includes a radio frequency component 901, a semiconductor die 902, a surface mount device 903, a wire bond 908, a package substrate 920, and an encapsulation structure 940. The package substrate 920 includes a pad 906 formed from a conductor placed inside. Additionally, the semiconductor die 902 includes pins or pads 904, and the wire bond 908 is used to connect the pad 904 of the die 902 to the pad 906 of the package substrate 920.

[0066] The semiconductor die 902 includes a load-modulated power amplifier 945, which may be implemented according to any of the embodiments herein.

[0067] The packaging substrate 920 is configured to accept multiple components, such as a radio frequency component 901 including, for example, a surface-mount capacitor and / or inductor, a semiconductor die 902, and a surface-mount device 903. In one packaging example, the radio frequency component 901 includes an integrated passive device (IPD).

[0068] As shown in Figure 12B, the package module 900 includes a plurality of contact pads 932. The plurality of contact pads 932 are located on the opposite side of the package module 900 from the side used to mount the semiconductor die 902. Configuring the package module 900 in this manner can assist in connecting the package module 900 to a circuit board, such as a telephone board for a mobile device. Examples of contact pads 932 can be configured to supply radio frequency signals, bias signals, and / or power (e.g., power supply voltage and ground) to the semiconductor die 902 and / or other components. As shown in Figure 12B, the electrical connection between the contact pads 932 and the semiconductor die 902 can be facilitated by a connection portion 933 via the package substrate 920. The connection portion 933 may represent an electrical path formed through the package substrate 920, such as a connection portion associated with vias and conductors of a multilayer package substrate.

[0069] In some embodiments, the package module 900 may also include one or more package structures that provide, for example, protection and / or facilitate handling. Such package structures may include an overmolding or encapsulation structure 940 formed on the package substrate 920 on which the components and dies are placed.

[0070] It should be understood that, although the package module 900 is described in the context of wire-bonded electrical connections, one or more features of this disclosure can also be implemented in other package configurations, such as a flip-chip configuration.

[0071] Figure 13 is a schematic diagram of one embodiment of a communication system 1130 that transmits an RF signal. The communication system 1130 includes a baseband processor 1107, a signal delay circuit 1108, a digital predistortion (DPD) circuit 1109, an I / Q modulator 1110, an observation receiver 1111, an intermodulation detection circuit 1112, a power amplifier 1113, a directional coupler 1114, a duplexing and switching circuit 1115, an antenna 1116, an envelope delay circuit 1121, a coordinate rotation digital calculation (CORDIC) circuit 1122, a shaping circuit 1123, a digital-to-analog converter 1124, and a reconfiguration filter 1125.

[0072] The communication system 1130 in Figure 13 shows an example of an RF system including a load-modulated power amplifier as taught herein. However, load-modulated power amplifiers can be used in a wide variety of RF systems.

[0073] The baseband processor 1107 operates to generate I and Q signals corresponding to the signal components of a sine wave or sine signal of a desired amplitude, frequency, and phase. For example, the I signal is used to represent the in-phase component of the sine wave, and the Q signal is used to represent the quadrature component of the sine wave, thereby providing an equivalent representation of the sine wave. In a given implementation example, the I and Q signals are provided to the I / Q modulator 1110 in digital form. The baseband processor 1107 may be any suitable processor configured to process baseband signals. For example, the baseband processor 1107 may include a digital signal processor, a microprocessor, a programmable core, or any combination thereof.

[0074] The signal delay circuit 1108 provides an adjustable delay to the I signal and the Q signal, and the envelope signal and the RF signal. IN It assists in controlling the relative consistency with the signal. The amount of delay provided by the signal delay circuit 1108 is controlled based on the amount of intermodulation detected by the intermodulation detection circuit 1112.

[0075] The DPD circuit 1109 operates to digitally shape the delayed I and Q signals from the signal delay circuit 1108, generating digitally pre-distorted (DPD) I and Q signals. In the illustrated embodiment, the pre-distortion provided by the DPD circuit 1109 is controlled based on the amount of intermodulation detected by the intermodulation detection circuit 1112. The DPD circuit 1109 plays a role in reducing distortion in the power amplifier 1113 and / or increasing the efficiency of the power amplifier 1113.

[0076] The I / Q modulator 1110 receives digitally pre-distorted I and Q signals, and these signals are converted into RF signals. INis processed to generate. For example, the I / Q modulator 1110 includes a DAC configured to convert the digitally pre-distorted I signal and Q signal into an analog format, a mixer that up-converts the analog I signal and Q signal to a radio frequency, and a signal combiner that combines the up-converted I signal and Q signal into an RF signal suitable for amplification by the power amplifier 1113. In a given implementation example, the I / Q modulator 1110 may include one or more filters configured to filter the frequency components of the processed signal.

[0077] The envelope delay circuit 1121 delays the I signal and Q signal from the baseband processor 1107. Additionally, the CORDIC circuit 1122 processes the delayed I signal and Q signal to generate a digital envelope signal representative of the envelope of the RF signal RF IN Although FIG. 13 shows one implementation example using the CORDIC circuit 1122, the envelope signal can also be obtained in other ways.

[0078] The shaping circuit 1123 operates to shape the digital envelope signal to enhance the performance of the communication system 1130. In a given implementation example, the shaping circuit 1123 includes a shaping table that maps each level of the digital envelope signal to a corresponding shaped envelope signal level. Envelope shaping can help control the linearity, distortion, and / or efficiency of the power amplifier 1113.

[0079] In the illustrated embodiment, the shaped envelope signal is a digital signal converted to an analog envelope signal by the DAC 1124. Additionally, the analog envelope signal is filtered by the reconstruction filter 又は1125 to generate an envelope signal suitable for modulating the load of the power amplifier 1113. In a given implementation example, the reconstruction filter 1125 includes a low-pass filter.

[0080] Continuing to refer to FIG. 13, the power amplifier 1113 receives the RF signal RF from the I / Q modulator 1110 and amplifies the RF signal RF IN to obtain the amplified RF signal RF OUTIn this example, this is supplied to the antenna 1116 via the duplexing and switching circuit 1115.

[0081] The directional coupler 1114 is positioned between the output of the power amplifier 1113 and the input of the duplexing and switching circuit 1115, allowing for measurement of the output power of the power amplifier 1113 without the insertion loss of the duplexing and switching circuit 1115. The output signal detected from the directional coupler 1114 is supplied to the observation receiver 1111. The observation receiver 1111 may include a mixer that generates down-converted I and Q signals, and a DAC that generates I and Q observation signals from the down-converted signals.

[0082] The intermodulation detection circuit 1112 determines the intermodulation product of the I observation signal and the Q observation signal and the I signal and Q signal from the baseband processor 1107. In addition, the intermodulation detection circuit 1112 controls the pre-distortion and / or the delay of the signal delay circuit 1108 provided by the DPD circuit 1109, and the envelope signal and RF signal RF IN It controls the relative consistency with respect to. In a given implementation example, the intermodulation detection circuit 1112 also plays a role in controlling the shaping provided by the shaping circuit 1123.

[0083] By including the feedback path from the output of the power amplifier 1113 and the baseband, the I and Q signals can be dynamically adjusted to optimize the operation of the communication system 1130. For example, configuring the communication system 1130 in this manner can assist in power control, transmitter fault compensation, and / or DPD execution.

[0084] Although shown as a single stage, the power amplifier 1113 may include one or more stages. Furthermore, the teachings herein are also applicable to communication systems that include multiple power amplifiers.

[0085] In conclusion

[0086] Unless the context explicitly requires otherwise, throughout the specification and claims, terms such as “includes,” “equip,” and so on should be interpreted in a comprehensive sense, the opposite of an exclusive or exhaustive sense, i.e., “includes but not limited to.” The term “combined,” as used herein, refers to two or more elements that may be directly connected or connected via one or more intermediate elements. Similarly, the term “connected,” as used herein, refers to two or more elements that may be directly connected or connected via one or more intermediate elements. In addition, where used in this application, the terms “here,” “above,” “below,” and similar terms refer to the entire application and not to any particular part of it. Where contextually permissible, terms in the above detailed description that use singular or plural numbers may also include plural or singular numbers. The terms “or” and “or” referring to a list of two or more items cover all of the following interpretations of the term: any of the items in the list, all of the items in the list, and any combination of the items in the list.

[0087] Furthermore, unless specifically stated or understood otherwise in the context in which they are used, conditional language used herein, in particular, such as “may,” “can,” “perhaps,” “for example,” and “like,” is generally intended to mean that a given embodiment includes a given feature, element, and / or state, while other embodiments do not. That is, such conditional language is generally not intended to imply that the feature, element, and / or state exists in any manner required for one or more embodiments, or that one or more embodiments necessarily include logic that determines, with or without the author’s input or prompt, whether or not these feature, element, and / or state are included, or should be done in any particular embodiment.

[0088] The above description of embodiments of the present invention is not intended to be exhaustive or to limit the invention to any specific form of the above disclosure. While specific embodiments and examples of the present invention are described above for illustrative purposes, various equivalent modifications are possible within the scope of the invention, as will be apparent to those skilled in the art. For example, while processes or blocks are presented in a given order, alternative embodiments may employ systems having routines or blocks with steps in a different order, and some processes or blocks may be deleted, moved, added, subdivided, combined, and / or modified. Each of these processes or blocks may be implemented in various different ways. Furthermore, while processes or blocks may be shown to be executed in series, these processes or blocks may instead be executed in parallel or at different times.

[0089] The teachings of the present invention given herein can be applied to other systems, not necessarily those described above. The elements and operations of the various embodiments described above may be combined to provide further embodiments.

[0090] While certain embodiments of the present invention have been described, these embodiments are presented only as examples and are not intended to limit the scope of this disclosure. In fact, the novel methods and systems described herein may be embodied in various other forms, and various omissions, substitutions, and modifications of the methods and systems described herein may be made without departing from the spirit of this disclosure. The appended claims and their equivalents are intended to cover forms or modifications that fall within the scope and spirit of this disclosure.

Claims

1. 1. A mobile device comprising: a transceiver configured to generate a radio frequency signal and an envelope signal that varies relative to an envelope of the radio frequency signal; a front-end system including a load modulated power amplifier configured to amplify the radio frequency signal; Including, The load modulation power amplifier comprises: a power amplifier configured to receive the radio frequency signal at an input and to provide an amplified radio frequency signal at an output; a controllable load impedance coupled to an output of the power amplifier; Including, the envelope signal is operable to control an impedance of the controllable load impedance to modulate a load at an output of the power amplifier; The controllable load impedance is a controllable capacitor controlled by said envelope signal; an output balun having a first winding coupled to an output of the power amplifier and a second winding coupled to the controllable capacitor; , including mobile devices.

2. The mobile device of claim 1 , wherein the transceiver includes a shaping circuit configured to shape the envelope signal based on calibration data.

3. 3. The portable device of claim 2, wherein the shaping circuit is operable to provide a flat gain versus input power characteristic to the power amplifier.

4. The power amplifier includes: An input balun; a pair of amplifiers coupled between the input balun and the output balun; The mobile device of claim 1 , comprising:

5. The second winding is a first terminal for outputting the amplified radio frequency signal; a second terminal coupled to the controllable capacitor; The mobile device of claim 1 , comprising:

6. The controllable capacitor comprises: A bipolar transistor; a load capacitor coupled to the collector of the bipolar transistor; Including, The portable device of claim 1 , wherein the envelope signal is operable to control a base of the bipolar transistor.

7. The mobile device of claim 1 , further comprising an antenna operable to transmit the amplified radio frequency signal.

8. The portable device of claim 1, further comprising a band switch having an input electrically connected to the second winding of the output balun.

9. The portable device of claim 8, wherein the second winding of the output balun is electrically connected between the input of the band switch and the controllable capacitor.

10. 1. A load modulation power amplifier system, comprising: a power amplifier configured to receive a radio frequency signal at an input and to provide an amplified radio frequency signal at an output; a controllable load impedance coupled to an output of the power amplifier; Including, the controllable load impedance is configured to receive an envelope signal that varies relative to an envelope of the radio frequency signal; the envelope signal is operable to control an impedance of the controllable load impedance to modulate a load at an output of the power amplifier; The controllable load impedance is a controllable capacitor controlled by said envelope signal; an output balun having a first winding coupled to an output of the power amplifier and a second winding coupled to the controllable capacitor; 1. A load modulated power amplifier system comprising:

11. The power amplifier includes: An input balun; a pair of amplifiers coupled between the input balun and the output balun; 11. The load modulation power amplifier system of claim 10, comprising:

12. The second winding is a first terminal for outputting the amplified radio frequency signal; a second terminal coupled to the controllable capacitor; 11. The load modulation power amplifier system of claim 10, comprising:

13. The controllable capacitor comprises: A bipolar transistor; a load capacitor coupled to the collector of the bipolar transistor; Including, The load modulation power amplifier system of claim 10 , wherein the envelope signal is operable to control the base of the bipolar transistor.

14. 1. A method of amplification in a mobile device, comprising: generating a radio frequency signal using a transceiver and an envelope signal that varies relative to an envelope of the radio frequency signal; amplifying the radio frequency signal using a power amplifier, the amplifying comprising receiving the radio frequency signal at an input of the power amplifier and providing an amplified radio frequency signal at an output of the power amplifier; modulating a load of the power amplifier using the envelope signal to control the impedance of a controllable load impedance coupled to an output of the power amplifier; Including, The method, wherein modulating the load of the power amplifier includes controlling a capacitance of a controllable capacitor coupled to an output balun.

15. The method of claim 14 , further comprising calibrating the power amplifier by shaping the envelope signal based on calibration data.

16. 16. The method of claim 15, wherein calibrating the power amplifier comprises providing a flat gain versus input power characteristic.

17. providing the amplified radio frequency signal to a first winding of the output balun; The method of claim 14 , wherein the controllable capacitor is coupled to a second winding of the output balun.

18. The power amplifier comprising: An input balun; a pair of amplifiers coupled between the input balun and the output balun; Including, 20. The method of claim 17, further comprising providing the amplified radio frequency signal from the pair of amplifiers to the first winding of the output balun.

19. The controllable capacitor, A bipolar transistor; a load capacitor coupled to the collector of the bipolar transistor; Including, 15. The method of claim 14, further comprising controlling a base of the bipolar transistor using the envelope signal.

20. The method of claim 14, further comprising transmitting the amplified radio frequency signal using an antenna.

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