HK1241148B - Enhanced amplifier efficiency through cascode current steering - Google Patents

Description

Enhanced amplifier efficiency through cascode current steering

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No. 62/116,464, filed on February 15, 2015, entitled “ENHANCED AMPLIFIEREFFICICIENCY THROUGH CASCODE CURRENT STEERING,” the disclosure of which is expressly incorporated herein by reference in its entirety.

Technical Field

The present application relates to power amplifiers for radio frequency (RF) applications.

Background Art

Power amplifiers (PAs) are widely used in networks to set the transmit power level of information-carrying signals. For example, PAs are used to set the pulsed energy of lasers in optical networks. PAs are also used in various wireless network devices, such as base stations and mobile devices, to set the transmit power level of radio frequency (RF) signals. PAs are also used in local area networks to allow both wired and wireless connections between various devices.

Managing PA operation in battery-powered mobile devices is important because PA power consumption often has a substantial impact on battery life. However, meeting power consumption targets can be detrimental to other goals, such as signal integrity in data packets and linearity in error control.

Some devices, such as wireless devices, utilize Doherty amplifiers to improve PA efficiency. In most cases, Doherty amplifiers have efficiency advantages over traditional single-ended amplifiers.

Some advanced modulation schemes that use peak-to-average ratios require amplifiers to operate several dB below their maximum saturated output power ( _Psat ) to maintain linearity. Because Doherty amplifiers have an efficiency peak of approximately 6 dB above _Psat , their linear efficiency can be improved. Furthermore, Doherty amplifiers add complexity to the PA due to the RF input splitter/phase shifter and output combiner.

Summary of the Invention

According to various implementations, the present application relates to a power amplifier (PA) comprising: a common emitter configured to receive a radio frequency (RF) signal. The PA further comprises: a carrier amplifier coupled to the common emitter to form a carrier cascode configuration, a first power supply voltage being provided to a collector of the carrier amplifier. The PA further comprises: a peaking amplifier coupled to the common emitter to form a peak cascode configuration, a second power supply voltage greater than the first power supply voltage being provided to a collector of the peaking amplifier.

In some implementations, a bias voltage is provided to each of the carrier amplifier and the peaking amplifier to allow the corresponding amplifier to be switched on and off.

In some implementations, when the output power (Pout) of the PA is less than a selected value, the carrier amplifier is turned on by setting the bias voltage of the carrier amplifier to a high level, and the peak amplifier is turned off by setting the bias voltage of the peak amplifier to a ground level. In some implementations, substantially all of the collector current of the PA is obtained from the first supply voltage to produce maximum or increased efficiency at the output power.

In some implementations, when Pout is greater than a selected value, the carrier amplifier is turned off by setting the bias voltage of the carrier amplifier to the ground level, and the peak amplifier is turned on by setting the bias voltage of the carrier amplifier to the high level. In some implementations, substantially all of the collector current of the PA is derived from the second supply voltage to produce an increase in maximum output power.

In some implementations, the selected value is the saturation power level (Psat) minus 3dB.

In some implementations, the carrier cascode configuration and the peak cascode configuration substantially preserve the gain of the PA in either configuration.

In some implementations, the PA has a minimized or reduced discontinuity in amplitude-to-amplitude (AM-AM) response during a transition between the first and second supply voltages.

In some implementations, the present application relates to a radio frequency (RF) module, comprising: a packaging substrate configured to accommodate a plurality of components. The RF module further comprises: a power amplifier (PA) implemented on the packaging substrate, the PA comprising a common emitter configured to receive an RF signal, the PA further comprising a carrier amplifier coupled to the common emitter to form a carrier cascode configuration, a first power supply voltage being provided to a collector of the carrier amplifier, the PA further comprising a peaking amplifier coupled to the common emitter to form a peak cascode configuration, a second power supply voltage greater than the first power supply voltage being provided to a collector of the peaking amplifier.

In some implementations, the RF module is a front-end module (FEM).According to some implementations, the PA of the RF module includes the functionality and/or features of any PA and/or amplification system described herein.

According to some teachings, the present application relates to a radio frequency (RF) device comprising: a transceiver that generates an RF signal. The RF device also includes a front-end module (FEM) in communication with the transceiver, the FEM including a packaging substrate configured to house multiple components, the FEM also including a power amplifier (PA) implemented on the packaging substrate, the PA including a common emitter configured to receive the RF signal, the PA also including a carrier amplifier coupled to the common emitter to form a carrier cascode configuration, a first power supply voltage being provided to the collector of the carrier amplifier, the PA also including a peaking amplifier coupled to the common emitter to form a peak cascode configuration, a second power supply voltage greater than the first power supply voltage being provided to the collector of the peaking amplifier. The RF device also includes an antenna in communication with the FEM, the antenna configured to transmit the amplified RF signal.

In some implementations, the RF device includes a wireless device. In some implementations, the wireless device includes at least one of a base station, a repeater, a mobile phone, a smartphone, a computer, a laptop, a tablet computer, and a peripheral device. According to some implementations, the PA of the FEM module includes the functionality and/or features of any PA and/or amplification system described herein.

For the purpose of summarizing this application, certain aspects, advantages and novel features of the present invention have been described herein. It should be understood that, according to any specific embodiment of the present invention, it is not necessary to realize all such advantages. Therefore, the present invention can be implemented or realized in a manner that realizes or optimizes one or a group of advantages taught herein, without realizing other advantages that may be taught or implied herein.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to enable a more detailed understanding of the present application, a more particular description may be given by reference to the features of various implementations, some of which are illustrated in the accompanying drawings. However, the drawings only illustrate the more relevant features of the present application and are therefore not to be considered restrictive, as the description may allow for the inclusion of other effective features.

FIG1 is a block diagram of a wireless system or structure according to some implementations.

2 is a block diagram of an amplification system according to some implementations.

3A-3E illustrate schematic diagrams of power amplifiers according to some implementations.

4 is a block diagram of an amplification system according to some implementations.

5 is a schematic diagram of a current steering cascode amplifier according to some implementations.

FIG6 illustrates an example graph of cascode bias control according to some implementations.

7 illustrates example current paths for the current steering cascode amplifier of FIG. 5 , according to some implementations.

8 illustrates additional example current paths of the current steering cascode amplifier of FIG. 5 , according to some implementations.

FIG. 9 illustrates example responses of a carrier amplifier and a peaking amplifier according to some implementations.

10 illustrates an example performance graph of a current steering cascode amplifier according to some implementations.

11 is a schematic diagram of an example radio frequency (RF) module according to some implementations.

12 is a schematic diagram of an example RF device according to some implementations.

As is customary, the various features illustrated in the accompanying drawings may not be drawn to scale. Accordingly, the dimensions of the various features may be arbitrarily expanded or reduced for clarity. In addition, some of the accompanying drawings may not illustrate all components of a given system, method, or apparatus. Finally, throughout the specification and drawings, the same reference numerals may be used to identify the same features.

DETAILED DESCRIPTION

The headings provided herein, if any, are for convenience only and do not necessarily affect the scope or meaning of the claimed invention.

1 , one or more features of the present application generally relate to a wireless system or structure 50 having an amplification system 52. In some embodiments, the amplification system 52 can be implemented as one or more devices, and such devices can be utilized in the wireless system/structure 50. In some embodiments, the wireless system/structure 50 can be implemented, for example, in a portable wireless device. Examples of such wireless devices are described herein.

FIG2 shows that the amplification system 52 of FIG1 typically includes a radio frequency (RF) amplifier assembly 54 having one or more power amplifiers (PAs). In the example of FIG2 , three PAs ( 60 a to 60 c ) are illustrated as forming the RF amplifier assembly 54. It should be understood that other numbers of PAs may also be implemented. It should also be understood that one or more features of the present disclosure may also be implemented in an RF amplifier assembly having other types of RF amplifiers.

In some embodiments, the RF amplifier assembly 54 may be implemented on one or more semiconductor dies, and such dies may be included in a packaged module such as a power amplifier module (PAM) or a front-end module (FEM). Such a packaged module is typically mounted on a circuit board associated with, for example, a portable wireless device.

The PAs (e.g., 60a to 60c) in the amplification system 52 are typically biased by a bias system 56. Additionally, the supply voltage for the PAs is typically provided by a power system 58. In some embodiments, either or both of the bias system 56 and the power system 58 may be included in the aforementioned package module with the RF amplifier assembly 54.

In some embodiments, the amplification system 52 may include a matching network 62. Such a matching network may be configured to provide input matching and/or output matching functionality for the RF amplifier assembly 54.

For purposes of this description, it should be understood that each of the PAs 60a to 60c of FIG2 can be implemented in a variety of ways. FIG3A to FIG3E illustrate non-limiting examples of how each of the PAs 60a to 60c of FIG2 can be configured. FIG3A illustrates an example PA having an amplifier transistor 64, wherein an input RF signal (RF_in) is provided to the base of the transistor 64, and an amplified RF signal (RF_out) is output through the collector of the transistor 64.

FIG3B shows an example PA having multiple amplifier transistors (e.g., 64a, 64b) arranged in multiple stages. An input RF signal (RF_in) is provided to the base of the first transistor 64a, and the amplified RF signal from the first transistor 64a is output through its collector. The amplified RF signal from the first transistor 64a is provided to the base of the second transistor 64b, and the amplified RF signal from the second transistor 64b is output through its collector, thereby generating the PA's output RF signal (RF_out).

In some embodiments, the aforementioned example PA configuration of Figure 3B may be illustrated as two or more stages as shown in Figure 3C. The first stage 64a may be configured as, for example, a driver stage, and the second stage 64b may be configured as, for example, an output stage.

FIG3D shows that in some embodiments, the PA can be configured as a Doherty PA. Such a Doherty PA can include amplifier transistors 64a, 64b, which are configured to provide carrier amplification and peak amplification of the input RF signal (RF_in) to generate an amplified output RF signal (RF_out). The input RF signal can be separated into a carrier portion and a peak portion by a splitter. The amplified carrier and peak signals can be combined by a combiner to generate an output RF signal.

FIG3E shows that in some embodiments, the PA can be implemented in a cascode configuration. An input RF signal (RF_in) can be provided to the base of a first amplifier transistor 64a operating as a common-emitter device. The output of the first amplifier transistor 64a can be provided via its collector and provided to the emitter of a second amplifier transistor 64b operating as a common-base device. The output of the second amplifier transistor 64b can be provided via its collector to generate an amplified output RF signal (RF_out) of the PA.

In the examples of Figures 3A to 3E, the amplifier transistor is described as a bipolar junction transistor (BJT) such as a heterojunction bipolar transistor (HBT). It should be understood that one or more features of the present application can also be implemented with or using other types of transistors such as field effect transistors (FETs).

FIG4 shows that, in some embodiments, the amplification system 52 of FIG2 can be implemented as a high voltage (HV) power amplification system 100. Such a system can include an HV power amplifier assembly 54, which is configured to include HV amplification operations of some or all of the PAs (e.g., 60a to 60c). As described herein, such PAs can be biased by a bias system 56. In some embodiments, the aforementioned HV amplification operations can be facilitated by an HV power supply system 58. In some embodiments, an interface system 72 can be implemented to provide interface functionality between the HV power amplifier assembly 54 and either or both of the bias system 56 and the HV power supply system 58.

Examples related to enhancing power amplifier (PA) efficiency through cascode current steering are described herein. It is noted that Doherty amplifiers can offer efficiency advantages over conventional single-ended amplifiers. In some embodiments, advanced modulation schemes using peak-to-average ratios require or expect the Doherty amplifier to operate several dB away from the maximum saturated output power ( _Psat ) to maintain linearity. Since Doherty amplifiers typically have an efficiency peak of approximately 6 dB away from P, their linear efficiency leaves room for improvement.

Disclosed herein are examples of how an efficiency response similar to that of a Doherty amplifier can be obtained without the complexity of a radio frequency (RF) input splitter/phase shifter and output combiner.

FIG5 illustrates an exemplary schematic diagram of a current-steering cascode amplifier 500 according to some implementations. As shown in FIG5 , the current-steering cascode amplifier 500 has a common emitter 510 configured to receive an input RF signal (RF _in 502) at its base and generate an output through its collector (RF _out 504). Such an output is shown as being provided to the emitter of a peaking amplifier 520 and also provided to the emitter of a carrier amplifier 530. The carrier amplifier 530 is shown as generating its output through its collector, and the peaking amplifier 520 is shown as generating its output through its collector. Accordingly, the common emitter 510 and the carrier amplifier 530 can form a carrier cascode configuration. Similarly, the common emitter 510 and the peaking amplifier 520 can form a peak cascode configuration.

5 , the collector nodes of carrier amplifier 530 and peaking amplifier 520 are shown coupled via DC blocking capacitive element 542. The collector of carrier amplifier 530 is shown coupled to the output node (RF _out 504) via DC blocking capacitive element 544.

The supply voltage _Vcc is 552 and is shown as being provided to the collector of the peaking amplifier 520 through a choke inductor element 554. The supply voltage 556 is shown as being provided to the collector of the carrier amplifier 530 through a choke inductor element 558.

Peaking amplifier 520 is shown biased at its base with a peak cascode bias voltage _Vcascode 562 from a peak bias system. Carrier amplifier 530 is shown biased at its base with a carrier cascode bias voltage _Vcascode 564 from a carrier bias system.

FIG6 illustrates an example graph 600 of cascode bias control according to some implementations. As shown in FIG6 , the carrier cascode bias voltage V _cascode 564 (solid line) and the peak cascode bias voltage V _cascode 562 (dashed line) vary as a function of the output power P _out . For example, the carrier cascode bias voltage V _cascode 564 is shown to have a value of approximately 2V when P out < Psat -3dB, and a value of approximately 0V when P out > Psat -3dB. The peak cascode bias voltage V _cascode 562 is shown to have a value of approximately 0V when P out < Psat -3dB, and a value of approximately 2V when P out > Psat -3dB.

With the aforementioned biasing configuration, when Pout<Psat-3dB, an example current path (e.g., _Icc path 700) can be obtained as shown in FIG7 . In such a state where the peak cascode bias voltage _Vcascode 562 is 0V (and therefore the peak amplifier 520 is off) and the carrier cascode bias voltage _Vcascode 564 is 2V (and therefore the carrier amplifier 530 is on), the collector current _Icc is shown flowing through the cascode arrangement of the carrier amplifier 530 and the common emitter 510 (e.g., _Icc path 700). The maximum _Pout in such a state is

Where R _LL is the load resistance.

Similarly, with the aforementioned biasing configuration, when Pout>Psat-3dB, an example current path (e.g., _Icc path 800) as shown in FIG8 can be obtained. In such a state where the peak cascode bias voltage _Vcascode 562 is 2V (and therefore the peak amplifier 520 is turned on) and the carrier cascode bias voltage _Vcascode 564 is 0V (and therefore the carrier amplifier 530 is turned off), the collector current _Icc is shown as flowing through the cascode arrangement of the peak amplifier 520 and the common emitter 510 (e.g., _Icc path 800). The maximum _Pout in such a state is

_Vcc2 /( _2RLL ) = _Vcc2 ^/ ( _2RLL ), ^where _RLL is the load resistance.

6 to 8 , two power supply voltages, _Vcc, are provided to the carrier amplifier 530 and the peaking amplifier 520, respectively. In some implementations, the power supply voltage _Vcc 552 for the peaking amplifier 520 can be provided, for example, from a step-up DC/DC converter. In some implementations, the power supply voltage 556 for the carrier amplifier 530 can be provided, for example, from a step-down converter.

6-8 , in the first region where Pout < Psat -3 dB, the cascode base voltage of the peaking amplifier 520 is pulled to ground, while the cascode base voltage of the carrier amplifier 530 is pulled high (e.g., 2 V). This configuration forces substantially all collector current to be drawn away from the supply ^voltage 556. The maximum output power of the PA in this configuration is _Vcc2 /( _4RLL ), at which maximum efficiency is achieved.

In the region of Pout > Psat - 3dB, the cascode base voltage of the peaking amplifier 520 is pulled high (e.g., 2V), while the cascode base voltage of the carrier amplifier 530 is pulled to ground. This configuration forces substantially all collector current to be drawn away from the supply voltage _Vcc 552. The maximum output power of the PA in this configuration is _Vcc2 ^/ ( _2RLL ) or 3dB higher than the carrier amplifier configuration.

Also note that the aforementioned supply rejection of the amplifier in the cascode configuration preserves the gain of the amplifier in either configuration. This effect can minimize or reduce any discontinuity in the amplitude-to-amplitude (AM-AM) response during the transition between the supply voltage _Vcc 552 and the supply voltage 556.

FIG9 illustrates example responses of a carrier amplifier and a peaking amplifier, according to some implementations. According to some implementations, graph 910 illustrates an example of power added efficiency (PAE) responses of the peaking amplifier and the carrier amplifier. According to some implementations, graph 920 illustrates additional examples of PAE responses of the peaking amplifier and the carrier amplifier. According to some implementations, graph 930 illustrates an example of amplitude-to-amplitude (AM-AM) responses of the peaking amplifier and the carrier amplifier. According to some implementations, graph 940 illustrates an example of amplitude-to-phase (AM-PM) responses of the peaking amplifier and the carrier amplifier.

FIG10 illustrates example performance graphs for a current-steering cascode amplifier as a whole, according to some implementations. According to some implementations, graph 1010 illustrates an example of power-added efficiency (PAE) versus output power ( _Pout ). According to some implementations, graph 1020 illustrates another example of PAE versus output power ( _Pout ). According to some implementations, graph 1030 illustrates an example of gain versus output power ( _Pout ). According to some implementations, graph 1040 illustrates an example of phase versus output power ( _Pout ).

FIG11 shows that, in some embodiments, some or all of the current-steering cascode amplifiers described herein can be implemented in a radio frequency (RF) module. Such a module can be, for example, a front-end module (FEM). In the example of FIG11 , module 1100 can include a packaging substrate 1102, and various components can be mounted on such a packaging substrate. For example, a front-end power management integrated circuit (FE-PMIC) component 1152, a power amplifier assembly 1154 including the current-steering cascode amplifier 500, matching components 1156, and a duplexer assembly 1158 can be mounted and/or implemented on and/or within packaging substrate 1102. Other components, such as a plurality of optional surface mount technology (SMT) devices 1104 and an antenna switch module (ASM) 1106, can also be mounted on packaging substrate 1102. While all of the various components are illustrated as being disposed on packaging substrate 1102, it should be understood that some components can be implemented on other components.

In some implementations, devices and/or circuits having one or more features described herein may be included in RF devices such as wireless devices. Such devices and/or circuits may be implemented in wireless devices directly, in the form of modules described herein, or in some combination thereof. In some embodiments, such wireless devices may include, for example, cellular phones, smartphones, handheld wireless devices with or without telephone functionality, wireless tablets, and the like.

FIG12 illustrates an example radio frequency (RF) device 1200 having one or more advantageous features described herein. According to some implementations, RF device 1200 is a wireless device. In the context of a module having one or more features described herein, such a module may be generally illustrated by dashed box 1100 and may be implemented, for example, as a front-end module (FEM). As described herein, such a module may include one or more PAs having a current steering feature. According to some implementations, the current steering feature operates similarly to the current steering cascode amplifier 500 described herein.

12 , power amplifiers (PAs) 1220 can receive their respective RF signals from transceiver 1210, which can be configured and operated in a known manner to generate RF signals to be amplified and transmitted and to process received signals. Transceiver 1210 is shown interacting with baseband subsystem 1208, which is configured to provide conversion between data and/or voice signals suitable for a user and RF signals suitable for transceiver 1210. Transceiver 1210 can also communicate with power management component 1206, which is configured to manage power for operation of wireless device 1200. Such power management can also control the operation of baseband subsystem 1208 and module 1100.

The baseband subsystem 1208 is shown connected to the user interface 1202 to facilitate various inputs and outputs of voice and/or data to and from the user. The baseband subsystem 1208 may also be connected to the memory 1204, which is configured to store data and/or instructions to facilitate the operation of the wireless device and/or to provide storage of information to the user.

In the example shown in FIG12 , the outputs of the PAs 1220 are shown matched (via corresponding matching circuits 1222) and routed to their respective duplexers 1224. Such amplified and filtered signal can be routed to the antenna 1216 via the antenna switch 1214 for transmission. In some embodiments, the duplexer 1224 can allow transmit and receive operations to be performed simultaneously using a common antenna (e.g., 1216). In FIG12 , the received signal is shown as being routed to an "Rx" path (not shown) that can include, for example, one or more low noise amplifiers (LNAs).

Many other wireless device configurations can utilize one or more of the features described herein. For example, a wireless device need not be a multi-band device. In other examples, a wireless device can include additional antennas such as a diversity antenna and additional connectivity features such as Wi-Fi, Bluetooth, and GPS.

Unless the context clearly requires otherwise, throughout the specification and claims, the words "comprises," "comprising," and the like should be interpreted in an inclusive sense, as opposed to an exclusive or exhaustive sense, that is, in the sense of "including but not limited to." As generally used herein, the word "coupled" refers to two or more elements that can be connected directly or by means of one or more intermediate elements. In addition, the words "herein," "above," "herein below," and words of similar meaning, when used in this application, should refer to this application as a whole and not to any specific part of this application. Where the context permits, words in the above description that use the singular or plural may also include the plural or singular, respectively. With respect to the word "or" when referring to a list of two or more items, the word covers all of the following interpretations of the word: any item in the list, all items in the list, and any combination of items in the list.

The above detailed description of the embodiment of the present invention is not intended to be exhaustive or to limit the present invention to the exact form disclosed above. Although specific embodiments of the present invention and examples have been described above for illustrative purposes, various equivalent modifications may be possible within the scope of the present invention as will be appreciated by those skilled in the art. For example, although processes or blocks are presented in a given order, alternative embodiments may perform processes with these steps or adopt systems with these blocks in different orders, 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 ways. In addition, although processes or blocks are sometimes shown as being performed serially, alternatively, these processes or blocks may also be performed in parallel, or may be performed at different times.

The teachings of the invention provided herein can be applied to other systems, not necessarily the system described above.The elements and acts of the various embodiments described above can be combined to provide further embodiments.

Although some embodiments of the present invention have been described, these embodiments are presented only as examples and are not intended to limit the scope of the present application. In fact, the novel methods and systems described herein may be implemented in a variety of other forms; in addition, various omissions, substitutions, and changes in the form of the methods and systems described herein may be made without departing from the spirit of the present application. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the present application.

Claims (20)

1. A power amplifier, comprising: Common emitter, configured to receive radio frequency signals; A carrier amplifier coupled to the common emitter to form a common-emitter, common-base configuration, providing a first power supply voltage to the collector of the carrier amplifier and coupling the base of the carrier amplifier to a first bias voltage, the first bias voltage varying as a function of the output power of the power amplifier; and A peak amplifier coupled to the common emitter to form a peak common emitter common base configuration, a second power supply voltage greater than the first power supply voltage is provided to the collector of the peak amplifier, and the base of the peak amplifier is coupled to a second bias voltage that varies as a function of the output power of the power amplifier. 2. The power amplifier of claim 1, wherein each of the first bias and the second bias allows the corresponding amplifier to be turned on and off. 3. The power amplifier according to claim 2, wherein when the output power of the power amplifier is less than the selected value, the carrier amplifier is turned on by setting the first bias voltage to a high level, and the peak amplifier is turned off by setting the second bias voltage to a ground level. 4. The power amplifier of claim 3, wherein substantially all of the collector current of the power amplifier is derived from the first power supply voltage in order to produce maximum or increased efficiency at the output power. 5. The power amplifier according to claim 3, wherein when the output power is greater than the selected value, the carrier amplifier is turned off by setting the first bias voltage to the ground level, and the peak amplifier is turned on by setting the second bias voltage to the high level. 6. The power amplifier of claim 5, wherein substantially all of the collector current of the power amplifier is derived from the second power supply voltage to produce an increase in maximum output power. 7. The power amplifier according to claim 5, wherein the selected value is the saturation power level minus 3dB. 8. The power amplifier of claim 2, wherein the carrier common-emitter common-base configuration and the peak common-emitter common-base configuration substantially preserve the gain of the power amplifier in either configuration. 9. The power amplifier of claim 2, wherein, during the transition between the first supply voltage and the second supply voltage, the power amplifier has a minimized or reduced discontinuity in the amplitude-to-amplitude response. 10. A radio frequency module, comprising: The packaging substrate is configured to accommodate multiple components; and A power amplifier implemented on the package substrate includes a common emitter configured to receive radio frequency signals, and a carrier amplifier coupled to the common emitter to form a carrier common emitter common base configuration. A first power supply voltage is provided to the collector of the carrier amplifier, and the base of the carrier amplifier is coupled to a first bias voltage, which varies as a function of the output power of the power amplifier. The power amplifier also includes a peak amplifier coupled to the common emitter to form a peak common emitter common base configuration, a second power supply voltage greater than the first power supply voltage is provided to the collector of the peak amplifier, and the base of the peak amplifier is coupled to a second bias voltage, which varies as a function of the output power of the power amplifier. 11. The radio frequency module according to claim 10, wherein the radio frequency module is a front-end module. 12. The radio frequency module of claim 10, wherein each of the carrier amplifier and the peak amplifier is provided with a bias voltage to allow the respective amplifier to be turned on and off. 13. The radio frequency module of claim 12, wherein when the output power of the power amplifier is less than the selected value, the carrier amplifier is turned on by setting the first bias voltage to a high level, and the peak amplifier is turned off by setting the second bias voltage to a ground level. 14. The radio frequency module of claim 13, wherein substantially all of the collector current of the power amplifier is derived from the first power supply voltage in order to produce maximum or increased efficiency at the output power. 15. The radio frequency module of claim 13, wherein when the output power is greater than the selected value, the carrier amplifier is turned off by setting the first bias voltage to the ground level, and the peak amplifier is turned on by setting the second bias voltage to the high level. 16. The radio frequency module of claim 15, wherein substantially all of the collector current of the power amplifier is derived from the second power supply voltage to produce an increase in maximum output power. 17. The RF module of claim 12, wherein the carrier common-emitter common-base configuration and the peak common-emitter common-base configuration substantially preserve the gain of the power amplifier in either configuration. 18. A radio frequency device, comprising: The transceiver is configured to generate radio frequency signals; A front-end module communicating with the transceiver, the front-end module including a package substrate configured to accommodate multiple components, the front-end module further including a power amplifier implemented on the package substrate, the power amplifier including a common emitter configured to receive radio frequency signals, the power amplifier further including a carrier amplifier coupled to the common emitter to form a carrier common-emitter common-base configuration, a first power supply voltage provided to the collector of the carrier amplifier, and the base of the carrier amplifier coupled to a first bias voltage, the first bias voltage varying as a function of the output power of the power amplifier, the power amplifier further including a peak amplifier coupled to the common emitter to form a peak common-emitter common-base configuration, a second power supply voltage greater than the first power supply voltage provided to the collector of the peak amplifier, and the base of the peak amplifier coupled to a second bias voltage, the second bias voltage varying as a function of the output power of the power amplifier; and An antenna that communicates with the front-end module is configured to transmit amplified radio frequency signals. 19. The radio frequency device of claim 18, wherein the radio frequency device includes a wireless device. 20. The radio frequency device of claim 19, wherein the wireless device comprises at least one of a base station, a repeater, a mobile phone, a smartphone, a computer, a laptop computer, a tablet computer, and a peripheral device.