Portable device, power amplification system, and method of power amplification

Abstract

To provide a power amplifier including a supply capacitor switching.SOLUTION: A power amplifier system 110 includes a power amplifier 102 that amplifies a radio frequency (RF) signal, a power management circuit 101 that controls the voltage level of supply voltage VCC of the power amplifier 102, a supply capacitor 103 including a first end connected to the supply voltage VCC, and a bulk n-type field effect transistor (NFET) switch. A power management circuit 101 can operate in a multi-supply control mode (for example, average power trace mode and envelope trace mode). Additionally, a bulk NFET switch is controlled based on the supply control mode of the power management circuit 101. The bulk NFET switch includes a ground NFET connected in series with a second end of the supply capacitor 103 and ground voltage, and a discharge NFET connected between the second end of the supply capacitor and the supply voltage VCC.SELECTED DRAWING: Figure 5

Description

[Technical Field]

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

[0002] In radio frequency (RF) communication systems, power amplifiers are used to amplify RF signals for transmission via antennas. Managing the power of RF signal transmission can be crucial for extending battery life and / or providing an appropriate transmission power level.

[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, laptops, and wearable electronic devices. The power amplifiers amplify RF signals, which may have frequencies in the range of approximately 30 kHz to 300 GHz, such as in the range of approximately 410 MHz to approximately 7.125 GHz for fifth-generation (5G) communication using frequency range 1 (FR1), or in the range of approximately 24.25 GHz to 52.6 GHz for 5G communication using frequency range 2 (FR2). [Overview of the Initiative]

[0004] In a given embodiment, the disclosure relates to a portable device. The portable device includes a power amplifier configured to amplify a radio frequency signal, a power management circuit configured to control the voltage level of the supply voltage of the power amplifier, the power management circuit being capable of operating in a selective supply control mode selected from a plurality of supply control modes, and a front-end system including a supply capacitor, the supply capacitor having a first end connected to the supply voltage, an n-type field-effect transistor ground switch connected between the second end of the supply capacitor and the ground voltage, and an n-type field-effect transistor discharge switch connected between the second end of the supply capacitor and the supply voltage. The n-type field-effect transistor ground switch and the n-type field-effect transistor discharge switch are controlled based on the selective supply control mode.

[0005] In some embodiments, the supply control modes include an average power tracking mode and an envelope tracking mode. According to certain embodiments, an n-type field-effect transistor ground switch is configured to be on in the average power tracking mode and off in the envelope tracking mode, and an n-type field-effect transistor discharge switch is configured to be off in the average power tracking mode and on in the envelope tracking mode.

[0006] In various embodiments, the n-type field-effect transistor discharge switch includes two or more n-type field-effect transistors connected in series. According to some embodiments, the front-end system further includes a voltage divider configured to bias the two or more n-type field-effect transistors. According to some embodiments, the voltage divider includes a first terminal connected to a supply voltage and a second terminal connected to a ground voltage via a mode transistor. According to some embodiments, a plurality of supply control modes include an average power tracking mode and an envelope tracking mode, and the mode transistor is configured to be on in the envelope tracking mode and off in the average power tracking mode.

[0007] In some embodiments, the n-type field-effect transistor ground switch and the n-type field-effect transistor discharge switch are mounted on a semiconductor die fabricated using a bulk silicon process.

[0008] In a given embodiment, the disclosure relates to a package module. The package module includes a package substrate and a first die mounted on the package substrate, and includes a power amplifier configured to amplify radio frequency signals and to receive power from a supply voltage controlled by a power management circuit. The package module further includes a supply capacitor having a first terminal mounted on the package substrate and connected to the supply voltage, and a second die mounted on the package substrate, the second die being manufactured using a bulk silicon process. The second die includes an n-type field-effect transistor ground switch connected between the second terminal of the supply capacitor and a ground voltage, and an n-type field-effect transistor discharge switch connected between the second terminal of the supply capacitor and the supply voltage.

[0009] In various embodiments, the power management circuit can operate in a selective supply control mode that indicates either an average power tracking mode or an envelope tracking mode, and the n-type field-effect transistor ground switch and the n-type field-effect transistor discharge switch are controlled based on the selective supply control mode. According to some embodiments, the n-type field-effect transistor ground switch is configured to be on in the average power tracking mode and off in the envelope tracking mode, and the n-type field-effect transistor discharge switch is configured to be off in the average power tracking mode and on in the envelope tracking mode.

[0010] In some embodiments, the n-type field effect transistor discharge switch includes two or more n-type field effect transistors connected in series. According to a certain number of embodiments, the second die further includes a voltage divider configured to bias two or more n-type field effect transistors. According to some embodiments, the voltage divider includes a first terminal connected to a supply voltage and a second terminal connected to a ground voltage via a mode transistor.

[0011] In various embodiments, the package module further includes a supply pin configured to receive a supply voltage, and a power management circuit exists outside the package module.

[0012] In a given embodiment, the present disclosure relates to a power amplifier system. The power amplifier includes a power amplifier configured to amplify a radio frequency signal, a power management circuit configured to control a voltage level of a supply voltage of the power amplifier, the power management circuit being operable in a selected supply control mode selected from a plurality of supply control modes, a supply capacitor including a first end connected to the supply voltage, an n-type field effect transistor ground switch connected between a second end of the supply capacitor and a ground voltage, and an n-type field effect transistor discharge switch connected between the second end of the supply capacitor and the supply voltage. The n-type field effect transistor ground switch and the n-type field effect transistor discharge switch are controlled based on the selected supply control mode.

[0013] In various embodiments, the plurality of supply control modes include an average power tracking mode and an envelope tracking mode. According to a certain number of embodiments, the n-type field effect transistor ground switch is configured to be turned on in the average power tracking mode and turned off in the envelope tracking mode, and the n-type field effect transistor discharge switch is configured to be turned off in the average power tracking mode and turned on in the envelope tracking mode.

[0014] In some embodiments, the n-type field effect transistor discharge switch includes two or more n-type field effect transistors connected in series. According to certain embodiments, the power amplifier system further includes a voltage divider configured to bias two or more n-type field effect transistors. According to various embodiments, the voltage divider includes a first terminal connected to a supply voltage and a second terminal connected to a ground voltage via a mode transistor. According to some embodiments, the plurality of supply control modes include an average power tracking mode and an envelope tracking mode, and the mode transistor is configured to be turned on in the envelope tracking mode and turned off in the average power tracking mode.

[0015] In various embodiments, the n-type field effect transistor ground switch and the n-type field effect transistor discharge switch are implemented on a semiconductor die fabricated using a bulk silicon process.

[0016] In a given embodiment, the present disclosure relates to a method of power amplification. The method includes amplifying a radio frequency signal using a power amplifier and controlling a voltage level of a supply voltage of the power amplifier using a power management circuit, where the supply voltage is coupled to a first end of a supply capacitor. The method further includes operating the power management circuit in a selected supply control mode selected from a plurality of supply control modes and controlling an n-type field effect transistor ground switch based on the selected supply control mode, where the n-type field effect transistor ground switch is connected between a second end of the supply capacitor and a ground voltage. The method further includes controlling an n-type field effect transistor discharge switch based on the selected supply control mode, where the n-type field effect transistor ground switch is connected between a second end of the supply capacitor and the supply voltage.

[0017] In various embodiments, the supply control modes include an average power tracking mode and an envelope tracking mode. According to some embodiments, the method further includes turning on an n-type field-effect transistor ground switch in the average power tracking mode and turning off the n-type field-effect transistor ground switch in the envelope tracking mode. According to some embodiments, the method further includes turning off an n-type field-effect transistor discharge switch in the average power tracking mode and turning on the n-type field-effect transistor discharge switch in the envelope tracking mode. [Brief explanation of the drawing]

[0018] [Figure 1] This is a schematic diagram of an example of a communication network. [Figure 2A] This is a schematic diagram of an example of a communication link using carrier aggregation. [Figure 2B] Figure 2A shows various examples of uplink carrier aggregation for a communication link. [Figure 2C] Figure 2A shows various examples of downlink carrier aggregation for a communication link. [Figure 3A] This graph shows the first example of power amplifier supply voltage versus time. [Figure 3B] This graph shows a second example of the power amplifier supply voltage versus time relationship. [Figure 3C] This graph shows a third example of the power amplifier supply voltage versus time relationship. [Figure 4] This is a schematic diagram of a power amplifier system according to one embodiment. [Figure 5] This is a schematic diagram of a power amplifier system according to another embodiment. [Figure 6A] This is a schematic diagram of a power amplifier system according to another embodiment. [Figure 6B] Figure 6A is a graph of an example of a supply mode switching waveform for a power amplifier system. [Figure 7A] This is a schematic diagram of a package module according to one embodiment. [Figure 7B] This is a schematic diagram of a cross-section of a package module along the line 7B-7B in Figure 7A. [Figure 8] This is a schematic diagram of a portable device according to one embodiment. [Modes for carrying out the invention]

[0019] The following detailed description of a given embodiment presents various descriptions of a particular embodiment. However, the innovation described herein can be embodied in numerous different forms defined and covered, for example, by the claims. In this specification, the same reference numeral refers to drawings showing identical or functionally similar elements. It should be understood that the elements shown in the drawings are not necessarily to scale. It should also be understood that a given embodiment may include more elements than shown in the drawings, and / or subsets of the elements shown in the drawings. Furthermore, some embodiments may also include any suitable combination of features from two or more drawings.

[0020] Figure 1 is a schematic diagram of an example of a communication network 10. The communication network 10 includes a macrocell base station 1, a small cell base station 3, and various examples of user equipment (UEs). User equipment (UEs) include a first portable device 2a, a wirelessly connected vehicle 2b, a laptop 2c, a stationary wireless device 2d, a wirelessly connected train 2e, a second portable device 2f, and a third portable device 2g.

[0021] Although specific examples of base stations and user equipment are shown in Figure 1, the communication network may include a wide variety of types and / or numbers of base stations and user equipment.

[0022] For example, in the illustrated example, the communication network 10 includes a macrocell base station 1 and a smallcell base station 3. The smallcell base station 3 may operate with relatively lower power, shorter range, and / or fewer concurrent users compared to the macrocell base station 1. The smallcell base station 3 may also be referred to as a femtocell, picocell, or microcell. Although the communication network 10 is shown to include two base stations, the communication network 10 may be implemented to include more or fewer base stations and / or other types of base stations.

[0023] Although various examples of user devices are presented, the teachings herein are applicable to a wide variety of user devices, including but not limited to mobile phones, tablets, laptops, Internet of Things (IoT) devices, wearable electronic devices, subscriber premises equipment (CPE), wirelessly connected vehicles, wireless relays, and / or a wide variety of other communication devices. Furthermore, user devices include not only currently available communication devices operating in cellular networks, but also subsequently developed communication devices that can be easily implemented in the systems, processes, methods and devices of the present invention described herein and claimed in the claims.

[0024] The communication network 10 illustrated in Figure 1 supports communication using various cellular technologies, including, for example, 4G LTE and 5G NR. In a given implementation example, the communication network 10 is further adapted to provide a wireless local area network (WLAN) such as Wi-Fi. Although various examples of communication technologies have been given, the communication network 10 can be adapted to support a wide variety of communication technologies.

[0025] Various communication links of the communication network 10 are depicted in Figure 1. Communication links can be duplicated (duplexed) in a wide variety of ways, including, for example, using frequency division duplication (FDD) and / or time division duplication (TDD). FDD is a type of radio frequency communication that uses different frequencies for transmitting and receiving signals. FDD can offer a number of advantages, such as high data rates and low latency. In contrast, TDD is a type of radio frequency communication that uses nearly the same frequency for transmitting and receiving signals, with the transmitting and receiving communications switching over time. TDD can offer a number of advantages, such as efficient use of the spectrum and variable allocation of throughput between the transmitting and receiving directions.

[0026] In a given implementation example, user equipment can communicate with a base station using one or more of 4G LTE, 5G NR, and WiFi technologies. In a given implementation example, Enhanced License-Assisted Access (eLAA) is used to aggregate one or more licensed frequency carriers (e.g., licensed 4G LTE and / or 5G NR frequencies) with one or more unlicensed carriers (e.g., unlicensed WiFi frequencies).

[0027] As shown in Figure 1, the communication link includes not only the communication link between the UE and the base station, but also UE-to-UE communication and base station-to-base station communication. For example, the communication network 10 can be implemented to support self-fronthaul and / or self-backhaul (such as between mobile device 2g and mobile device 2f).

[0028] Communication links can operate across a wide variety of frequencies. In a given implementation example, communication is supported using 5GNR technology over one or more frequency bands below 6 gigahertz (GHz) and / or over one or more frequency bands above 6 GHz. For example, a communication link may have frequency range 1 (FR1), frequency range 2 (FR2), or a combination thereof. In one embodiment, one or more portable devices support the HPUE power class specification.

[0029] In a given implementation example, a base station and / or user equipment communicate using beamforming. For example, beamforming can be used to converge signal strength to overcome path loss, such as the high loss associated with communication over high signal frequencies. In a given embodiment, one or more user devices, such as mobile phones, communicate using beamforming in the millimeter-wave frequency band in the range of 30 GHz to 300 GHz, and / or in the upper centimeter-wave frequency band in the range of 6 GHz to 30 GHz, more specifically 24 GHz to 30 GHz.

[0030] Different users of the communication network 10 can share available network resources, such as the available frequency spectrum, in a wide variety of ways.

[0031] In one example, Frequency Division Multiple Access (FDMA) is used to divide a single frequency band into multiple frequency carriers. In addition, one or more carriers are allocated to a specific user. Examples of FDMA include, but are not limited to, single-carrier FDMA (SC-FDMA) and orthogonal FDMA (OFDMA). OFDMA is a multi-carrier technique that divides the available bandwidth into many mutually orthogonal narrowband subcarriers, which can be allocated separately to different users.

[0032] Other examples of shared access include, but are not limited to, time-division multiplexing (TDMA), where users are allocated specific time slots to use frequency resources; code-division multiplexing (CDMA), where frequency resources are shared among different users by assigning each user a unique code; spatial-division multiplexing (SDMA), where beamforming is used to provide spatially divided shared access; and non-orthogonal multiplexing (NOMA), where power domains are used for multiple access. For example, NOMA may be used to serve a large number of users at the same frequency, time, and / or code but at different power levels.

[0033] Enhanced Mobile Broadband (eMBB) refers to technologies that increase the system capacity of LTE networks. For example, eMBB may refer to communications with a peak data rate of at least 10 Gbps and a minimum of 100 Mbps per user. Ultra-High Reliability Low Latency Communications (uRLLC) refers to technologies for communications with extremely low latency, for example, less than 2 milliseconds. uRLLC can be used for mission-critical communications such as autonomous driving and / or remote surgery applications. Massive Machine-Type Communications (mMTC) refers to low-cost, low-data-rate communications associated with wireless connectivity to everyday objects, such as communications associated with Internet of Things (IoT) applications.

[0034] The communication network 10 in Figure 1 can be used to support a wide variety of advanced communication functions, including but not limited to eMBB, uRLLC, and / or mMTC.

[0035] Figure 2A is a schematic diagram of an example of a communication link using carrier aggregation. By using carrier aggregation, the bandwidth of the communication link can be increased by supporting communication across multiple frequency carriers, thereby increasing the user data rate and improving network capacity by utilizing fragmented spectral distribution.

[0036] In the illustrated example, a communication link is provided between a base station 21 and a mobile device 22. As shown in Figure 2A, the communication link includes a downlink channel (DL) used for RF communication from the base station 21 to the mobile device 22 and an uplink channel (UL) used for RF communication from the mobile device 22 to the base station 21.

[0037] Although Figure 2A shows carrier aggregation in the context of FDD communication, carrier aggregation can also be used for TDD communication.

[0038] In a given implementation example, the communication link can provide asymmetric data rates for the downlink and uplink channels. For example, the communication link can support a relatively high downlink data rate to enable high-speed streaming of multimedia content to a mobile device, while providing a relatively low data rate for data uploads from the mobile device to the cloud.

[0039] In the illustrated example, the base station 21 and the mobile device 22 communicate via carrier aggregation, which can be used to selectively increase the bandwidth of the communication link. Carrier aggregation includes adjacent aggregation, in which 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 in different bands.

[0040] In the example shown in FIG. 2A, the uplink channel includes three aggregated component carriers f

[0042] , UL1 , UL2 , UL3 , f UL2 and f UL3 . Additionally, the downlink channel includes five aggregated component carriers f DL1 , f DL2 , f DL3 , f DL4 and f DL5 . Despite showing an example of component carrier aggregation, more or fewer carriers can be aggregated for the uplink and / or downlink. Further, the number of carriers to be aggregated can be changed over time to achieve the desired uplink data rate and downlink data rate.

[0041] For example, the number of carriers aggregated for uplink communication and / or downlink communication for a particular mobile device can change over time. For example, the number of carriers to be aggregated can change when the device moves through the communication network and / or when the network usage situation changes over time.

[0042] FIG. 2B shows various examples of uplink carrier aggregation for the communication link of FIG. 2A. FIG. 2B includes a first carrier aggregation scenario 31, a second carrier aggregation scenario 32, and a third carrier aggregation scenario 33, which schematically depict three types of carrier aggregation.

[0043] Carrier aggregation scenarios 31-33 include a first component carrier f UL1 , a second component carrier f UL2 , and a third component carrier f UL3This shows different spectral distributions for the given carriers. Although Figure 2B is shown in the context of aggregating three component carriers, carrier aggregation can also be used to aggregate more or fewer carriers. Furthermore, although shown in the context of uplink, the aggregation scenario is also applicable to downlink.

[0044] The first carrier aggregation scenario 31 represents continuous in-band carrier aggregation in which component carriers that are adjacent in frequency and within a common frequency band are aggregated. For example, in the first carrier aggregation scenario 31, component carrier f located continuously within the first frequency band BAND1 is aggregated. UL1 ,f UL2 and f UL3 To depict the summation of these.

[0045] Continuing to refer to Figure 2B, the second carrier aggregation scenario 32 represents an intraband discontinuous carrier aggregation in which two or more component carriers at non-adjacent frequencies but within a common frequency band are aggregated. For example, in the second carrier aggregation scenario 32, component carrier f, which is discontinuous but located within the first frequency band, is aggregated. UL1 ,f UL2 and f UL3 To depict the summation of these.

[0046] Third carrier aggregation scenario 33 represents intraband discontinuous carrier aggregation in which component carriers that are non-adjacent frequencies and located within multiple frequency bands are aggregated. For example, in third carrier aggregation scenario 33, component carrier f of the first frequency band BAND1 UL1 and f UL2 And the component carrier f of the second frequency band BAND2 UL3 This depicts the conclusion.

[0047] Figure 2C shows various examples of downlink carrier aggregation for the communication link in Figure 2A. These examples involve the first component carrier fDL1 , second component carrier f DL2 Third component carrier f DL3 , fourth component carrier f DL4 and the 5th component carrier f DL5 Various carrier aggregation scenarios 34-38 for different spectral distributions are depicted. Although Figure 2B is shown in the context of aggregating five component carriers, carrier aggregation can also be used to aggregate more or fewer carriers. Furthermore, although shown in the context of downlink, the aggregation scenarios are also applicable to uplink.

[0048] The first carrier aggregation scenario 34 depicts the aggregation of component carriers located consecutively within the same frequency band. Additionally, the second and third carrier aggregation scenarios 35 and 36 depict two examples of aggregations that are discontinuous but located within the same frequency band. Furthermore, the fourth and fifth carrier aggregation scenarios 37 and 38 depict two examples of aggregations in which component carriers located at non-adjacent frequencies and within multiple frequency bands are aggregated. As the number of component carriers to be aggregated increases, the complexity of the possible carrier aggregation scenarios also increases.

[0049] Referring to Figures 2A-2C, the individual component carriers used in carrier aggregation may have various frequencies, including, for example, frequency carriers in the same band or multiple bands. Additionally, carrier aggregation is applicable to implementations where the individual component carriers have approximately the same bandwidth, and is also applicable to implementations where the individual component carriers have different bandwidths.

[0050] A designated communication network allocates a primary component carrier (PCC) or anchor carrier for uplinks and a PCC for downlinks to a specific user device. Additionally, if a mobile device communicates using a single frequency carrier for uplink or downlink, that user device communicates using a PCC. To improve bandwidth for uplink communication, an uplink PCC can be aggregated with one or more uplink secondary component carriers (SCCs). Additionally, to improve bandwidth for downlink communication, a downlink PCC can be aggregated with one or more downlink SCCs.

[0051] In a given implementation example, the communication network provides network cells for each component carrier. Additionally, the primary cell operates using PCC, while the secondary cell operates using SCC. The primary and secondary cells may have different coverage areas due to differences in carrier frequency and / or network environment.

[0052] Licensed-Assisted Access (LAA) is a downlink carrier aggregation in which licensed frequency carriers associated with a mobile network operator (i) are aggregated together with unlicensed spectrum frequency carriers such as WiFi. LAA uses downlink PCCs in the licensed spectrum to carry control and signaling information associated with the communication link, while unlicensed spectrum is aggregated for wider downlink bandwidth where available. LAA may operate through dynamic adjustment of secondary carriers to avoid and / or coexist with WiFi users. Enhanced Licensed-Assisted Access (eLAA) is an advanced form of LAA that aggregates licensed and unlicensed spectrum for both downlink and uplink.

[0053] Power amplifier with supply capacitor switching

[0054] In mobile applications such as cellular communication systems, extending battery life is crucial. One operation that consumes a significant amount of battery charge is power amplification, or amplification of RF signals for wireless transmission.

[0055] To extend battery life by increasing efficiency, portable devices may include power management circuits that control the voltage level of the power amplifier's supply voltage. For example, the power management circuit can employ various power management techniques to reduce power dissipation and extend battery life by improving the power added efficiency (PAE) of the power amplifier by changing the voltage level of the power amplifier's supply voltage over time.

[0056] One power management technique for power amplifiers is average power tracking (APT). In this case, a DC / DC converter or other suitable voltage regulator is used to generate the supply voltage for the power amplifier based on the average output power of the power amplifier. For example, when APT is implemented, the supply voltage can be set to a specific voltage level over a certain time interval based on the average output power over that time interval (for example, it can be set to a fixed voltage level over the transmission frame).

[0057] Another technique for improving the efficiency of power amplifiers is envelope tracking (ET). In this case, the power amplifier's supply voltage is controlled in relation to the envelope of the RF signal. That is, as the voltage level of the RF signal's envelope increases, the voltage level of the power amplifier's supply voltage may increase. Similarly, as the voltage level of the RF signal's envelope decreases, the voltage level of the power amplifier's supply voltage decreases, reducing power consumption.

[0058] The power amplifier system is often multimode and may be specified to operate in linear mode (APT mode) with a static DC power supply or in quasi-compressed mode (ET mode) with a dynamically changing power supply.

[0059] 4G / 5G waveforms include amplitude modulation (AM) characteristics, which result in rapid changes in the current characteristics of the power amplifier. Furthermore, since the finite impedance of the power amplifier supply network can degrade the linearity of the power amplifier, it is preferable to have a large capacitance value in the supply network during APT operation. Conversely, during ET operation, since the power amplifier supply is specified to support high-frequency modulation, a large amount of capacitance cannot be tolerated in the power amplifier supply network.

[0060] For example, a mobile device may include a shared power management circuit that can be configured in APT mode or ET mode, depending on the signal power level and operating characteristics, for example, whether or not 3G, 4G, and / or 5G waveforms are used. In APT mode, it is desirable for the power management circuit to drive a large capacitance (e.g., in the range of 1uF), while in ET mode (especially for 5G applications), it is desirable for the load capacitance to be limited to several hundred pF for a wide envelope tracking bandwidth. For 5G applications in APT mode, it is desirable for the power amplifier to operate with a large supply capacitance in the range of several nanofarads (nF) to meet the adjacent channel power ratio (ACPR) and / or adjacent channel leakage power ratio (ACLR) specifications.

[0061] A power amplifier with a supply capacitor switch is provided herein. In a given embodiment, the power amplifier system includes a power amplifier for amplifying an RF signal, a power management circuit for controlling the voltage level of the supply voltage of the power amplifier, a supply capacitor having a first terminal connected to the supply voltage, and a bulk n-type field-effect transistor (NFET) switch. The power management circuit can operate in multiple supply control modes, including, for example, APT mode and ET mode. Additionally, the bulk NFET switch is controlled based on the supply control mode of the power management circuit. The bulk NFET switch includes a ground NFET connected in series with the second terminal of the supply capacitor and the ground voltage, and a discharge NFET connected between the second terminal of the supply capacitor and the supply voltage.

[0062] Therefore, power amplifiers can be designed to support multiple supply control modes, such as APT mode and ET mode, and to operate with optimal or near-optimal performance between these modes. Furthermore, the supply capacitors can be switched using a low-cost, low-complexity switching solution that utilizes only NFET devices in bulk silicon technology.

[0063] In contrast, the approach using bulk silicon p-type field-effect transistors (PFETs) can provide isolation (e.g., using a triple-well CMOS process) to avoid voltage fluctuations below ground and / or forward bias of substrate parasitic capacitance, but suffers significant difficulties in supporting low-voltage DC supply conditions and / or the additional well capacitance of the large PFETs significantly limits the minimum capacitance state in ET mode. In another example, an NFET switch can be connected between the supply capacitor and ground, and a charge pump can be used to bias the gate of the NFET switch above the supply voltage. However, this approach requires an additional pin interface to supply the charge pump circuit and increases the risk of clock spurious signals (clock spurious) disrupting the power amplifier transmit spectrum. In yet another example, SOI techniques can be used to avoid substrate effects, but these SOI techniques add significant costs due to the complex semiconductor process.

[0064] Figure 3A is Graph 47, which shows the first example of power amplifier supply voltage versus time. Graph 47 plots the RF signal voltage 41, the RF signal envelope 42, and the power amplifier supply voltage 43 against time. Graph 47 corresponds to an example waveform of an implementation where the power amplifier supply voltage 43 is substantially fixed.

[0065] It can be important that the power amplifier supply voltage 43 of the power amplifier has a higher voltage than the RF signal 41. For example, if the power amplifier is powered using a power amplifier supply voltage with a smaller amplitude than the RF signal, the RF signal will be clipped, which can lead to signal distortion and / or other problems. In other words, it can be important that the power amplifier supply voltage 43 is greater than the voltage of the envelope 42. However, it is desirable to reduce the voltage difference between the power amplifier supply voltage 43 and the envelope 42 of the RF signal 41. This is because the area between the power amplifier supply voltage 43 and the envelope 42 can represent energy loss. This energy loss can reduce battery life and increase the heat generated in the wireless device.

[0066] Figure 3B is Graph 48, which shows a second example of power amplifier supply voltage versus time. Graph 48 plots the RF signal voltage 41, the RF signal envelope 42, and the power amplifier supply voltage 44 against time. Graph 48 corresponds to an example of the waveform in an implementation example where the power amplifier supply voltage 44 is generated by envelope tracing.

[0067] Envelope tracking is a technique that can be used to increase the power added efficiency (PAE) of a power amplifier system by efficiently controlling the voltage level of the power amplifier supply voltage in relation to the envelope of the RF signal amplified by the power amplifier. That is, as the envelope of the RF signal increases, the voltage supplied to the power amplifier may also increase. Similarly, as the envelope of the RF signal decreases, the voltage supplied to the power amplifier decreases, and power consumption decreases.

[0068] In contrast to the power amplifier supply voltage 43 in Figure 3A, the power amplifier supply voltage 44 in Figure 3B changes in relation to the envelope 42 of the RF signal 41. Since the area between the power amplifier supply voltage 44 and the envelope 42 in Figure 3B is smaller than the area between the power amplifier supply voltage 43 and the envelope 42 in Figure 3A, the graph 48 in Figure 3B can be associated with a power amplifier system with high energy efficiency.

[0069] Figure 3C is Graph 49, which shows a third example of power amplifier supply voltage versus time. Graph 49 plots the RF signal voltage 41, the RF signal envelope 42, and the power amplifier supply voltage 45 against time. Graph 49 corresponds to an example waveform of an implementation where the power amplifier supply voltage 45 is generated by average power tracking (APT).

[0070] APT (Advanced Printing Test) is a technique for improving the efficiency of power amplifiers. In this case, the voltage level of the power amplifier's supply voltage is controlled based on the power amplifier's average output power. When operating with APT, the voltage level of the power amplifier's supply voltage is substantially fixed for a given time slot or time interval, but for subsequent time slots, it is adjusted based on the average output power (e.g., transmit power control level). APT can achieve gain more efficiently than a fixed power amplifier supply voltage, but its gain efficiency is lower than that of envelope tracking. However, envelope tracking can be more complex, costly, and / or overhead than APT.

[0071] Figure 4 is a schematic diagram of one embodiment of a power amplifier system 70. The illustrated power amplifier system 70 includes a switch 51, an antenna 52, a directional coupler 54, a power management circuit 60, a bias control circuit 61, a power amplifier 62, a transceiver 63, and a baseband processor 64.

[0072] Although Figure 4 shows one embodiment of a power amplifier system, the teachings herein are applicable to power amplifier systems implemented in a wide variety of ways. For example, a power amplifier system may include more or fewer components, different component arrangements, and / or components implemented in different ways.

[0073] In the illustrated embodiment, the transceiver 63 includes a power amplifier control circuit 66, an I / Q modulator 67, a mixer 68, and an analog-to-digital converter (ADC) 69. Not shown in Figure 4 for clarity, the transceiver 63 can also process signals received from one or more antennas (e.g., antenna 52 and / or other antennas) via one or more receiving paths. Furthermore, the transceiver 63 can be implemented in other embodiments, including but not limited to these, using different implementation examples of the transmission path, observation path, and / or power amplifier control circuit.

[0074] The baseband processor 64 may be used to generate in-phase (I) and quadrature (Q) signals that can be used to represent a sine wave or sine signal of a desired amplitude, frequency, and phase. For example, the I signal may be used to represent the in-phase component of a sine wave, and the Q signal may be used to represent the quadrature component of a 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 67 in digital form. The baseband processor 64 may be any suitable processor configured to process baseband signals. For example, the baseband processor 64 may include a digital signal processor, a microprocessor, a programmable core, or any combination thereof. Furthermore, in some implementation examples, two or more baseband processors 64 may be included in the power amplifier system 70.

[0075] The I / Q modulator 67 is configured to receive the I signal and the Q signal from the baseband processor 64, process the I signal and the Q signal, and generate an RF signal. For example, the I / Q modulator 67 may include a plurality of digital-to-analog converters (DACs) that convert the I signal and the Q signal into analog format, a mixer that upconverts the I signal and the Q signal to RF, and a signal coupler that combines the upconverted I signal and the Q signal to produce an RF signal suitable for amplification by the power amplifier 62. In a given implementation example, the I / Q modulator 67 may include one or more filters configured to filter the frequency components of the signal being processed.

[0076] The power amplifier 62 can receive an RF signal from the I / Q modulator 67 and, if effective, can supply the amplified RF signal to the antenna 52 via the switch 51. The directional coupler 54 can be placed between the output of the power amplifier 62 and the input of the switch 51. This allows for measurement of the output power of the power amplifier 62 without the insertion loss of the switch 51. However, power measurements with other configurations are also possible.

[0077] In this embodiment, switch 51 includes an antenna switch and / or a band switch. Switch 51 may further include one or more supply control switches (each connected to a corresponding supply capacitor) implemented according to the teachings herein. Such supply control switches can be used for any or all of the stages of the power amplifier 62.

[0078] In the illustrated configuration, a detection output signal from the directional coupler 54 is supplied to the mixer 68, which multiplies the detection output signal by a reference signal of a controlled frequency. The mixer 68 operates to generate a downshifted signal by downshifting the frequency components of the detection output signal. The downshifted signal may be supplied to the ADC 69, which can convert the downshifted signal into a digital format suitable for processing by the baseband processor 64. By including a feedback path between the output of the power amplifier 62 and the baseband processor 64, the baseband processor 64 can be configured to dynamically adjust the I and Q signals to optimize the operation of the power amplifier system 70. For example, configuring the power amplifier system 70 in this manner can assist in controlling the PAE and / or linearity of the power amplifier 62.

[0079] In the illustrated embodiment, the power management circuit 60 receives a power control signal from the transceiver 63 and controls the supply voltage of the power amplifier 62. In a predetermined implementation example, the transceiver 63 is electrically connected to the power management circuit 60 via a serial interface, and the power management circuit 60 receives the power control signal via the serial interface.

[0080] As shown in Figure 4, the power management circuit 60 supplies a first supply voltage V to the input stage of the power amplifier 62. CC1 Then, a second supply voltage V for supplying power to the output stage of the power amplifier 62. CC2 The power management circuit 60 generates the first supply voltage V in order to improve the PAE of the power amplifier system. CC1 and / or second supply voltage V CC2 The voltage level can be controlled. Although one embodiment is shown with two controllable supply voltages, the power management circuit can also control the voltage levels of more or fewer supply voltages. In a given implementation example, the power amplifier operates with one or more controllable supply voltages and one or more substantially fixed supply voltages.

[0081] In the illustrated embodiment, the power control signal instructs the power management circuit 60 to operate in a specific supply control mode, such as APT mode or ET mode. That is, in this embodiment, the power amplifier control circuit 66 of the transceiver 63 controls the selected supply control mode.

[0082] As shown in Figure 4, the bias control circuit 61 receives one bias control signal from the transceiver 63 and generates multiple bias control signals for the power amplifier 62. Additionally, the bias control circuit 61 generates multiple bias control signals based on one bias control signal.

[0083] One bias control signal indicates the supply control mode in which the power management circuit 60 operates, and the bias control circuit 61 generates multiple bias control signals based on the indicated supply control mode. In a given implementation example, the transceiver 63 is electrically connected to the bias control circuit 61 via a serial interface, and the bias control circuit 61 receives a control word indicating the selected supply control mode via the serial interface.

[0084] Figure 5 is a schematic diagram of a power amplifier system 110 of another embodiment. The power amplifier system 110 includes a power management circuit 101, a power amplifier 102, a supply capacitor 103, and a switch die 104.

[0085] As shown in Figure 5, the power amplifier 102 receives the RF input signal RF IN The power amplifier 102 receives the RF input signal RF IN The RF output signal is amplified and RF OUT Although depicted as including a single stage to generate the power amplifier voltage V, the power amplifier 102 may include an additional stage. The power amplifier 102 receives the power amplifier voltage V from a power management circuit 101, also referred to here as a power management integrated circuit (PMIC). CC The power amplifier 102 receives the power amplifier supply voltage V via a choke inductor. In a given implementation example, the power amplifier 102 receives the power amplifier supply voltage V via a choke inductor. CC A bipolar transistor having a collector that receives the power amplifier voltage V, or a choke inductor via a bipolar transistor or choke inductor. CC It includes a field-effect transistor (FET) having a drain that receives current.

[0086] The power management circuit 101 controls the power amplifier supply voltage V of the power amplifier 102. CC It controls the voltage level. The power management circuit 101 is a multimode power management circuit capable of operating in two or more modes, which may include APT mode and ET mode.

[0087] As shown in Figure 5, the switch die 104 includes a supply capacitor switch 105, which may be implemented according to any of the embodiments present herein. In a given embodiment, the switch die 104 may include one or more other components to increase integration.

[0088] The supply capacitor switch 105 is controlled (for example, to open or closed) based on the mode of the power management circuit 101, which is indicated by the mode signal MODE.

[0089] As shown in Figure 5, the supply capacitor 103 supplies the power amplifier supply voltage V CC It includes a first terminal (also referred to here as the first end) connected to the supply capacitor switch 105, and a second terminal (also referred to here as the second end) connected to the supply capacitor switch 105.

[0090] By controlling the state of the supply capacitor switch 105, the supply capacitor 103 is selectively included to control the power amplifier supply voltage V CC It can be filtered / stabilized.

[0091] Figure 6A is a schematic diagram of a power amplifier system 210 of another embodiment. The power amplifier system 210 has a power amplifier supply voltage V CC A power management integrated circuit (PMIC) (not shown in Figure 6A) that generates the power amplifier supply voltage V CC The system includes a power amplifier (not shown in Figure 6A) powered by a dynamo, a bulk silicon switch die 201, a first supply capacitor C1, and a second supply capacitor C2. In this example, the bulk silicon switch die 201 is a flip-chip die, and bump inductances L1, L2, and L3 (corresponding to the inductances of the bump pads of the die) are shown for predetermined pads of the die 201.

[0092] In the illustrated embodiment, the bulk silicon switch die 201 includes pins or pads 202a, 202b, 202c and 202d, a first NFET M1, a second NFET M2A / M2B, a third NFET M3, gate resistors RG1 and RG2, voltage divider resistors R1 and R2, a gate capacitor CG, and an electrostatic discharge (ESD) protection circuit including a forward diode D1 and reverse diodes D2A, D2B, ... D2M, D2N.

[0093] Pin 202b supplies voltage V (via bump inductance L2) CC Pin 202c is connected to the first terminal of the supply capacitor C1, while pin 202a is connected to the second terminal of the supply capacitor C1 (via bump inductance L1). Additionally, pin 202c is connected to ground (via bump inductance L3), and pin 202d receives the APT enable signal APT_EN.

[0094] In the illustrated embodiment, the NFET M1 is switched to the ground side of the capacitor C1. This significantly simplifies the design because the APD activation signal APT_EN can directly control the gate of the NFET switch without the need to bias the gate of the switch FET with a complex circuit such as a charge pump.

[0095] Caution is required during ET operation. This is because, since capacitor C1 can be fully charged, the low supply voltage forces the drain of the NFET ground switch (M1) below the chip ground voltage, resulting in a forward bias on the board parasitic capacitance.

[0096] In the illustrated embodiment, the discharge NFET (implemented using a series connection of M2A and M2B in this example) becomes active during ET mode and short-circuits capacitor C1, so that capacitor C1 is discharged to the single diode voltage. As a result, almost no charge remains in capacitor C1, so the supply V CC The low-voltage transition does not cause a forward bias in the substrate parasitic capacitance. Discharge NFETs are also called discharge switches.

[0097] In an effort to increase the robustness of the discharge switch, the device is divided into segments, and in this embodiment, it is configured in a stacked configuration M2A / M2B. Similarly, the gate bias is biased using resistor dividers R1 and R2. As a result, all drain-gate voltages, source-gate voltages, and drain-source voltages are divided, and the voltages handling the discharge switch are substantially doubled compared to a single-transistor configuration. However, the discharge switch may be implemented using more or fewer transistors.

[0098] An additional diode structure, placed in parallel with the discharge switch, provides an ESD protection path for this relatively small NFET structure. Since the NFET M1 is large, self-protection is achieved in this example via a natural snapback breakdown mechanism.

[0099] The use of a discharge switch offers the advantage of enabling low-cost process technologies through the use of an NFET-only switching architecture. Furthermore, the relatively small FET size and the absence of a bias well structure result in low off-state capacitance.

[0100] Figure 6B is a graph of an example of a supply mode switching waveform for the power amplifier system shown in Figure 6A.

[0101] APT activation signal APT_EN and supply voltage V CC An example waveform is drawn. Supply voltage V CC As shown in the diagram, it operates through various 1μs and 3μs transitions.

[0102] Figure 7A is a schematic diagram of a package module 300 according to one embodiment. Figure 7B is a schematic diagram of a cross-section of the package module 300 along the line 7B-7B in Figure 7A.

[0103] The package module 300 includes a power amplifier die 301, a switch die 302, a surface mount component 303, a wire bond 308, a package substrate 320, and an encapsulation structure 340. The package substrate 320 includes a pad 306 formed from a conductor placed inside. Additionally, the dies 301 and 302 include a pad 304, and the wire bond 308 is used to connect the pads 304 of the dies 301 and 302 to the pads 306 of the package substrate 320.

[0104] The power amplifier die 301 and the switch die 302 are implemented according to one or more features of the present disclosure. In a given implementation example, the switch die 302 includes a supply capacitor switch. The supply capacitor switch is in series with a supply capacitor formed at least partially using a surface-mount capacitor mounted on a package substrate. To enhance integration, the switch die 302 may include an antenna switch (e.g., a transmit / receive (T / R) switch) and / or a band switch. The switch die 302 may include a pin that receives a control signal indicating the supply control mode of a power management circuit (which may be included on or outside the package module 300).

[0105] In a given implementation example, dies 301 and 302 may be manufactured using different processing techniques. In one example, the power amplifier die 301 is manufactured using a heterojunction bipolar transistor (HBT) process, and the switch die 302 is manufactured using a bulk silicon process.

[0106] The packaging substrate 320 may be configured to accept multiple components, such as dies 301, 302 and surface mount components 303, which may include surface mount capacitors and / or inductors.

[0107] As shown in Figure 7B, the package module 300 includes a plurality of contact pads 332. The plurality of contact pads 332 are located on the opposite side of the package module 300 from the side used to mount the dies 301, 302. Configuring the package module 300 in this manner can facilitate connecting the package module 300 to a circuit board, such as a telephone board for a wireless device. An example of the contact pads 332 can be configured to supply RF signals, bias signals, power low voltages, and / or power high voltages to the dies 301, 302, and / or surface mount components 303. As shown in Figure 7B, the electrical connection between the contact pads 332 and the die 301 can be facilitated by a connection portion 333 via the package substrate 320. The connection portion 333 may represent an electrical path formed through the package substrate 320, such as a connection portion associated with vias and conductors of a multilayer package substrate.

[0108] In some embodiments, the package module 300 may also include one or more package structures, for example, that provide protection to the package module 300 and / or facilitate its handling. Such package structures may include an overmolding or encapsulation structure 340 formed on the package substrate 320 and the components and dies placed thereon.

[0109] It should be understood that, although the package module 300 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.

[0110] Figure 8 is a schematic diagram of one embodiment of the portable device 800. 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.

[0111] Although the portable device 800 illustrates an example of an RF system that may include one or more features of the present disclosure, the teachings herein are also applicable to electronic systems that are implemented in a wide variety of ways.

[0112] 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, WLAN (e.g., Wi-Fi), WPAN (e.g., Bluetooth® and ZigBee®), WMAN (e.g., WiMAX), and / or GPS technology.

[0113] 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 8. In one example, a separate component (e.g., a separate circuit or die) may be provided to handle a predetermined type of RF signal.

[0114] As shown in Figure 8, the transceiver 802 is connected to the front-end system 803 and the power management circuit 805 using a serial interface 809. All or some of the illustrated RF components may be controlled by the serial interface 809 to configure the portable device 800 during initialization and / or full operation. In other embodiments, a baseband processor 801 is additionally or alternatively connected to the serial interface 809 to operate to configure one or more RF components, such as components of the front-end system 803 and / or the power management system 805.

[0115] 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 one or more supply capacitor switches 810, one or more power amplifiers (PAs) 811, one or more low-noise amplifiers (LNAs) 812, one or more filters 813, one or more switches 814, and one or more duplexers 815. However, other implementations are also possible.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] The portable device 800 may operate with beamforming in a given implementation example. For example, the front-end system 803 may include a phase shifter with variable phase controlled by the transceiver 802. Additionally, the phase shifter is controlled to provide beamforming and directivity for transmitting and / or receiving signals using the antenna 804. For example, in the context of signal transmission, the phase of the transmit signal supplied to the antenna 804 is controlled so that the signal radiated from the 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 phase is controlled so that more signal energy is received when the signal arrives at the antenna 804 from a particular direction. In a given implementation example, the antenna 804 includes one or more arrays of antenna elements to enhance beamforming.

[0121] 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 processing. The baseband system 801 provides a digital representation of the transmit signal to the transceiver 802, which processes this to generate an 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 8, the baseband system 801 is coupled to a memory 806 to facilitate the operation of the portable device 800.

[0122] 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.

[0123] 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 power amplifier (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).

[0124] The power management system 805 can operate in a selectable supply control mode, such as APT mode or ET mode. In the illustrated embodiment, the selectable supply control mode of the power management system 805 is controlled by a transceiver 802. In a given implementation example, the transceiver 802 controls the selectable supply control mode using a serial interface 809. One or more supply control switches 810 are opened or closed based on the selectable supply control mode.

[0125] As shown in Figure 8, 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. Although the power management system 805 is shown separately from the front-end system 803, in a given implementation example, all or part of the power management system 805 (e.g., the PA supply control circuit) may be integrated into the front-end system 803.

[0126] application

[0127] Some of the embodiments described above have provided examples relating to wireless or portable devices. However, the principles and advantages of these embodiments can be used for any other system or device requiring a power amplifier system.

[0128] Such power amplifier systems can be implemented in various electronic devices. Examples of electronic devices may include, but are not limited to, consumer electronic products, components of consumer electronic products, and electronic test equipment. Examples of electronic devices also include, but are not limited to, memory chips, memory modules, optical network or other communication network circuits, and disk driver circuits. Examples of consumer electronic products include, but are not limited to, mobile phones, telephones, televisions, computer monitors, computers, handheld computers, personal digital assistants (PDAs), microwave ovens, refrigerators, automobiles, stereo systems, cassette recorders or players, DVD players, CD players, VCRs, MP3 players, radios, camcorders, cameras, digital cameras, portable memory chips, washing machines, dryers, washer / dryer units, photocopiers, facsimile machines, scanners, multifunction peripheral devices, watches, clocks, and the like. Furthermore, electronic devices may also include unfinished products.

[0129] In conclusion

[0130] 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.

[0131] Furthermore, unless specifically stated or understood otherwise in the context in which they are used, conditional language used herein, in particular, such as “can,” “may,” “may,” “for example,” and “like,” is generally intended to indicate 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 features, elements, and / or states are included, or should be done in any particular embodiment.

[0132] 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.

[0133] 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.

[0134] 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 power amplifier configured to amplify a radio frequency signal; a power management circuit configured to control a voltage level of a supply voltage of the power amplifier; Front-end system Including, the power management circuitry is operable in a selected supply control mode selected from a plurality of supply control modes; The front-end system includes: a supply capacitor having a first end connected to the supply voltage; a n-type field effect transistor ground switch connected between the second end of the supply capacitor and a ground voltage; an n-type field effect transistor discharge switch connected between the second end of the supply capacitor and the supply voltage; Including, the n-type field effect transistor discharge switch comprises two or more n-type field effect transistors in series; the n-type field effect transistor ground switch and the n-type field effect transistor discharge switch are controlled based on the selective supply control mode; The front-end system further comprises a voltage divider configured to bias the two or more n-type field effect transistors.

2. The portable device of claim 1 , wherein the plurality of supply control modes include an average power tracking mode and an envelope tracking mode.

3. the n-type field effect transistor ground switch is configured to be on in the average power tracking mode and off in the envelope tracking mode; The portable device of claim 2 , wherein the n-type field effect transistor discharge switch is configured to be off in the average power tracking mode and on in the envelope tracking mode.

4. 2. The portable device of claim 1, wherein the voltage divider includes a first terminal connected to the supply voltage and a second terminal connected through a mode transistor to the ground voltage.

5. the plurality of supply control modes include an average power tracking mode and an envelope tracking mode; The portable device of claim 4 , wherein the mode transistor is configured to be on in the envelope tracking mode and off in the average power tracking mode.

6. 10. The portable device of claim 1, wherein the n-type field effect transistor ground switch and the n-type field effect transistor discharge switch are implemented on a semiconductor die fabricated using a bulk silicon process.

7. 1. A power amplifier system comprising: a power amplifier configured to amplify a radio frequency signal; a power management circuit configured to control a voltage level of a supply voltage of the power amplifier; a supply capacitor having a first end connected to the supply voltage; a n-type field effect transistor ground switch connected between the second end of the supply capacitor and a ground voltage; an n-type field effect transistor discharge switch connected between the second end of the supply capacitor and the supply voltage; Voltage divider and Including, the n-type field effect transistor discharge switch comprises two or more n-type field effect transistors in series; the power management circuitry is operable in a selected supply control mode selected from a plurality of supply control modes; the n-type field effect transistor ground switch and the n-type field effect transistor discharge switch are controlled based on the selective supply control mode; The voltage divider is configured to bias the two or more n-type field effect transistors.

8. 8. The power amplifier system of claim 7, wherein the plurality of supply control modes include an average power tracking mode and an envelope tracking mode.

9. the n-type field effect transistor ground switch is configured to be on in the average power tracking mode and off in the envelope tracking mode; 9. The power amplifier system of claim 8, wherein the n-type field effect transistor discharge switch is configured to be off in the average power tracking mode and to be on in the envelope tracking mode.

10. 8. The power amplifier system of claim 7, wherein the voltage divider includes a first terminal connected to the supply voltage and a second terminal connected through a mode transistor to the ground voltage.

11. the plurality of supply control modes include an average power tracking mode and an envelope tracking mode; The power amplifier system of claim 10 , wherein the mode transistor is configured to be on in the envelope tracking mode and off in the average power tracking mode.

12. 8. The power amplifier system of claim 7, wherein the n-type field effect transistor ground switch and the n-type field effect transistor discharge switch are implemented on a semiconductor die fabricated using a bulk silicon process.

13. 1. A method of power amplification comprising: amplifying a radio frequency signal using a power amplifier; controlling a voltage level of a supply voltage of the power amplifier using a power management circuit, the supply voltage being coupled to a first end of a supply capacitor; operating the power management circuitry in a selected supply control mode selected from a plurality of supply control modes; controlling an n-type field effect transistor ground switch based on the selected supply control mode, the n-type field effect transistor ground switch being connected between a second end of the supply capacitor and a ground voltage; controlling an n-type field effect transistor discharge switch based on the selected supply control mode, the n-type field effect transistor discharge switch including two or more n-type field effect transistors in series, and the n-type field effect transistor ground switch connected between a second end of the supply capacitor and the supply voltage; biasing the two or more n-type field effect transistors using a voltage divider; A method comprising:

14. The method of claim 13 , wherein the plurality of supply control modes includes an average power tracking mode and an envelope tracking mode.

15. turning on the n-type field effect transistor ground switch in the average power tracking mode; turning off the n-type field effect transistor ground switch in the envelope tracking mode; 15. The method of claim 14, further comprising:

16. turning on the n-type field effect transistor discharge switch in the average power tracking mode; turning off the n-type field effect transistor discharge switch in the envelope tracking mode; 15. The method of claim 14, further comprising:

17. The method of claim 13, wherein the voltage divider includes a first terminal connected to the supply voltage and a second terminal connected to the ground voltage through a mode transistor.

18. The method of claim 17, wherein the plurality of supply control modes include an average power tracking mode and an envelope tracking mode.

20. The method of claim 17, the method further comprising: turning on the mode transistor in the envelope tracking mode; and turning off the mode transistor in the average power tracking mode.

19. The method of claim 13, wherein the n-type field effect transistor ground switch and the n-type field effect transistor discharge switch are implemented on a semiconductor die fabricated using a bulk silicon process.

20. The portable device of claim 1, further comprising an antenna configured to transmit the amplified radio frequency signal provided by the power amplifier.

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