Ultra-compact multiband transmitter utilizing robust AM-PM distortion self-suppression technology

Abstract

This disclosure relates to an ultra-compact multiband transmitter utilizing robust AM-PM distortion self-suppression technology. A communication device includes a power amplifier that generates a power signal based on one or more operating frequency bands of communication data, and drives and generates amplitude in the output stage of the power amplifier. The final stage may include an output passive network that suppresses amplitude modulation to phase modulation (AM-PM) distortion. During back-off power mode, the bias of the capacitive elements of the output power network components can be adjusted to minimize overall capacitance variation. The output passive network can also generate a flat phase response between two operating resonances.

Description

[0001] Divisional Application Instructions

[0002] This application is a divisional application of Chinese Patent Application No. 201780016437.6, filed on January 24, 2017, entitled "Ultra-compact multi-band transmitter utilizing robust AM-PM distortion self-suppression technology".

[0003] Citation of relevant applications

[0004] This application claims priority to U.S. Application No. 15 / 068,179, filed March 11, 2016, the entire contents of which are incorporated herein by reference. Background Technology

[0005] Modern wireless systems utilize multi-band and multi-mode operation to simultaneously support multiple different communication standards. These rapidly growing demands pose significant challenges to the development of future radio frequency (RF) transmitters, and especially power amplifiers (PAs). A popular solution for multi-band PAs is to directly assemble multiple single-band PAs on a single chip or multi-chip module. However, this approach can have several drawbacks, such as larger chip / module area, increased cost, dedicated antenna interfaces to each PA, potential for off-chip switches, and complex packaging. Tunable passive networks can also be used to achieve multi-band impedance matching and power combining in RF PAs. These tunable components typically involve a direct trade-off between passive losses and frequency range, and are susceptible to reliability issues related to tunable components such as varactor diodes and switched-capacitor banks. Attached Figure Description

[0006] Figure 1 An exemplary communication device, including at least an exemplary power amplifier, is shown according to the described aspects;

[0007] Figure 2 Exemplary drive circuits and power amplifiers are shown according to the various aspects described.

[0008] Figure 3 The power amplifier assembly is shown according to the various aspects described.

[0009] Figure 4 An example illustration of the compensation and output passive network based on the described aspects is shown;

[0010] Figure 5 An example output passive network based on the described aspects is shown;

[0011] Figure 6Example simulation illustrations related to the example power amplifier are shown, based on the described aspects;

[0012] Figure 7 A flowchart illustrating an exemplary method based on the described aspects is shown;

[0013] Figure 8 An exemplary mobile communication device having a power amplifier assembly system according to the described aspects is shown. Detailed Implementation

[0014] This disclosure will now be described with reference to the accompanying drawings, wherein the same reference numerals are always used to refer to the same elements, and the structures and devices shown therein are not necessarily drawn to scale. As used herein, the terms “component,” “system,” “interface,” etc., are intended to refer to computer-related entities, hardware, software (e.g., in execution), and / or firmware. For example, a component can be a processor, a process running on a processor, a controller, an object, an executable file, a program, a storage device, electronic circuitry, and / or a computer having processing capabilities. For example, an application running on a server and the server itself can also be components. One or more components may reside within a process, and components may be located on one computer and / or distributed among two or more computers. This document may describe a group of elements or a group of other components, wherein the term “group” can be interpreted as “one or more.”

[0015] The use of words as examples is intended to present concepts in a concrete manner. As used in this application, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or". That is, unless otherwise stated or clear from the context, "X adopts A or B" is intended to mean any natural inclusive arrangement. That is, if X adopts A; X adopts B; or X adopts both A and B, then "X adopts A or B" is satisfied in any of the foregoing cases. Furthermore, the articles "a" and "an" as used in this application and the appended claims should generally be understood to mean "one or more" unless otherwise stated or clearly pointed to from the context in the singular form. In addition, with regard to the use of the terms "comprising," "including," "having," "having," "containing," or variations thereof in the Detailed Description and the claims, these terms are intended to be inclusive in a manner similar to the term "comprising".

[0016] Considering the aforementioned shortcomings and ongoing objectives, various aspects of multi-band communication devices (e.g., transmitters that may be based on highly linear dual-band mixed-signal polarity power amplifier architectures) can provide fully integrated single-chip solutions in mass CMOS technology, while eliminating or significantly reducing amplitude modulation to phase modulation distortion generated during the power amplification stage. Embodiments herein disclose a power amplifier with a self-suppression or self-compensating bias scheme technique for communication / mobile devices involving simultaneous dual-band operation, load-pull impedance matching, parallel power combining, and even-order harmonic suppression, to maximize power amplifier efficiency using a compact on-chip transformer without any tunable passive components or switches.

[0017] For example, a communication device may be a transmitter or transceiver of a mobile phone or other mobile communication system that may include a power amplifier, wherein the power amplifier self-suppresses phase distortion as part of amplification modulation, which may be referred to as amplitude modulation to phase modulation (AM-PM) distortion. AM-PM distortion can refer to a form of nonlinear phase distortion caused by the nonlinear characteristics of circuit components (e.g., power amplifiers) based on the input amplitude. When the input amplitude is modulated, the phase modulation of the output can be nonlinear, and this then leads to an increase in out-of-band noise and an increase in the error vector amplitude (EVM).

[0018] For example, the disclosed power amplifier system is operable to utilize the inherent parasitic capacitance of the power amplifier's output stage (output passive network) to minimize the total capacitance variation that causes phase distortion. For instance, a power amplifier with multiple unit power amplifier cells can receive driver signals according to the operating frequency band of the input signal being processed, and the output passive network can combine signals from each unit power amplifier cell, deliver power to an antenna or antenna port, and further suppress AM-PM distortion by utilizing the flat phase response of a multi-resonant structure.

[0019] A unity power amplifier unit may include several parallel capacitor units that are absorbed by and become part of the output passive network. Capacitors can be integrated as part of different unity power amplifier units for capacitance across various transistor terminals. For example, these capacitors may span the drain, source, and gate terminals of the transistors in each unity power amplifier unit and can be charged and discharged in response to the power amplifier's operation. During power back-off mode, certain capacitor units can be manipulated to activate or deactivate using suppression components with transistors operating in predetermined operating modes. Therefore, the generated parasitic capacitance can be further controlled by utilizing the output passive network to mitigate AM-PM distortion at the power amplifier output, thus achieving a self-suppression scheme for suppressing inherent parasitic capacitances that cause phase distortion.

[0020] Furthermore, the output passive network of the power amplifier can be coupled to or integrated with the power amplifier as a multiresonant network to perform impedance matching, power combining, even-order harmonic suppression, and differential-to-single-ended conversion across a wide frequency range (one octave) using a single transformer footprint. Other aspects and details of this disclosure are further described below with reference to the accompanying drawings.

[0021] refer to Figure 1 , Figure 1 An exemplary communication or mobile device 100, including a power amplifier, is illustrated according to the described aspects. The communication device 100 may include, for example, a mobile or wireless device, and may also include a digital baseband processor 102, an RF front-end 104, and an antenna port 108 for connection to an antenna 106. The device 100 may include an exemplary power amplifier 110 as part of the digital baseband processor 102 or the RF front-end 104. The digital baseband processor 102 or the RF front-end 104 may include such a power amplifier 110 or multiple power amplifiers operating in parallel or coupled together. The RF front-end 104 may be coupled to the digital baseband processor 102 and the antenna port 108, which may be configured using the antenna 106.

[0022] In one aspect, power amplifier 110 is operable to provide a power signal along the transmitter path for transmission according to various operating frequency bands. Power amplifier 110 can operate in multi-band or multi-mode operation to simultaneously support multiple communication standards with various operating frequency bands. Rapidly growing demands pose challenges to the development of future radio frequency (RF) transmitters, especially power amplifiers. One solution for multi-band power amplifiers could be to directly assemble multiple single-band PAs on a chip or on a multi-chip module. However, this can result in a larger chip / module area, increased cost, dedicated antenna interfaces to each power amplifier, potential for off-chip switches, and complex packaging. Furthermore, tunable passive networks can also be used to achieve multi-band impedance matching and power combining for RF power amplifiers. However, these solutions are subject to direct trade-offs between passive losses and tuning range, as well as reliability issues. To address at least some of these issues, power amplifier 110 can include a highly linear dual-band mixed-signal polarity power amplifier architecture that provides a fully integrated single-chip solution in batch CMOS technology, according to the described aspects or embodiments.

[0023] In one example, power amplifier 110 may include multiple power amplifier components or unit power amplifier units, each configured to provide a power signal along a transmitter path (e.g., a path to antenna port 108) based on driver signals received according to one or more operating bands or frequencies. Power amplifier 110 may be further integrated into an output passive network, which may be a matching network component. The output stage may combine power signals processed from different unit power amplifier units / components of power amplifier 110. For example, the output passive network of power amplifier 110 may be further operated to suppress AM-PM distortion or phase distortion at the output based on or depending on whether power amplifier 110 operates in back-off power mode or saturation power mode. In this way, the output passive network of power amplifier component 110 can utilize a flat phase response across a wide frequency range to achieve a robust phase response to nonlinear output capacitance variations of the power amplifier. For example, power amplifier component 110 may be operable to adjust the bias of any number of unit power amplifier unit components of power amplifier 110 to minimize the total drain capacitance variation along the full operating power range or the operating frequency range of operation. Thus, the output passive network of power amplifier 110 can operate as a multi-resonant network to perform impedance matching, power combining, even-harmonic suppression, and differential-to-single-ended conversion across a wide frequency range (one octave) using a single transformer coverage area. The output passive network (matched resonant network component) of power amplifier assembly 110 can also provide a flat phase response across a wide bandwidth, such that variations in output capacitance result in minimal signal phase changes. Therefore, power amplifier 110 can produce excellent AM-PM performance across a wide bandwidth.

[0024] refer to Figure 2 , Figure 2An example communication system with a power amplifier (PA) 110' is illustrated according to various aspects or embodiments. PA 110' (e.g., a CMOS power amplifier or other PA) may include a driver stage component 202, one or more unit PA unit components 204, and an output passive network or impedance matching network 206 for generating power signals for transmissions involved in multi-band (e.g., uplink and downlink frequency operating bands) and multi-mode operation simultaneously utilizing different communication standards (e.g., LTE, 3GPP, etc.). PA 110' may generate AM-PM self-rejection to output a signal that utilizes the inherent parasitic capacitance of the PA output power stage to compensate for nonlinear capacitance variations. The output passive network 206 may also function as a multi-resonant matching network, where a flat phase response is also used to minimize residual AM-PM distortion of PA 110' throughout operation in both back-off and saturation operating modes. For example, PA 110' is operable to generate minimized AM-PM distortion or phase distortion due to the nonlinear capacitance of one or more unit PA cells, for example by mitigating one or more parasitic capacitances of one or more transistors (e.g., M1-4, such as PMOS, NMOS, or another transistor type) coupled to each active unit PA cell 204.

[0025] Driver stage 202 includes one or more driver stage components X1-X2 along one or more single or differential drive paths. n-1 This is used to generate the drive signal for power amplification at PA 110'. Driver stage components X1-X2 n-1 Processing electronic signals (e.g., radio frequency (RF) voltage signals, V) RF - V RF + (etc.), and provides regulated drive signals to the unit PA unit component 204. Each of the (one or more) driver stage components 202 may include one or more comparators or amplifiers 208 and 210 respectively associated with the differential drive path. The driver stage 202 is operable to regulate or control the unit PA unit component 204 by providing bias signals or drive signals to the gates of transistors (e.g., M1 and M2) and voltage bias (Vbias) to the gates of thick oxide transistors M3 and M4, for example, according to different operating modes (e.g., saturation mode, back-off power mode) and according to one or more different operating frequency bands being processed by the PA 110'-based application. Therefore, the drive signals can maintain the operation of subsequent stages of PA 110' according to the different characteristics of the unit PA unit component 204.

[0026] In one example, unit PA unit component 204 supplies / drives signals from driver stage component 202 to operate one or more transistors M3 and M4 in both back-off and saturation modes. Back-off mode can refer herein to a reduction in the power supplied or provided at unit PA unit component 204 or any group of transistors (e.g., M3 and M4 together). Saturation mode can refer to an increase in power when the PA component (e.g., each unit PA unit component 204, PA component 204, transistor M3, or transistor M4) is fully operated or supplied, such as exceeding the threshold voltage for thick oxide transistors M3 and M4, or transistors M1 and M4. Although PA 110' is shown as having a differential path, a single transmission path is also contemplated, as will be understood by those skilled in the art.

[0027] PA 110' may experience AM-PM distortion or phase distortion due to amplitude variations and fluctuations in the various capacitances of the unit PA cell assembly 204 (e.g., from capacitors Cgs, Cgd, and Cdb). Capacitor Cgs provides capacitance across the source and gate terminals, receiving driver signals to drive or power transistors M3 and M4. Capacitor Cgd of the unit PA cell assembly 204 provides capacitance between the gate and drain terminals of transistors M3 and M4.

[0028] Transistors M3 and M4 may include thick oxide transistors having a thicker oxide layer than transistors M1 and M2, which include thin oxide transistors (having a smaller or thinner oxide layer). For example... Figure 2 In the PA 110' cascode topology shown, the capacitor Cgd of the thick oxide transistors M3 and M4 can be a major contributor to the AM-PM distortion of PA110' because capacitor Cgd can be more nonlinear with respect to the power / voltage swing level and is further directly loaded at the output passive network 206 of PA 110'. This nonlinear capacitance Cgd loaded onto the output passive network 206 of PA 110' can change the resonant frequency of the output passive network 206 of PA 110' (the resonant frequency can typically be tuned to the maximum power level), which leads to phase distortion according to the output power level (as in AM-PM distortion). The capacitance of capacitor Cgd can be related to the width (W) and length (L) of the transistor devices (e.g., M3, M4), the gate-drain overlap capacitance per unit width (Cov), and the total gate capacitance (Cgg).

[0029] One way to address the AM-PM phase distortion generated from the power amplifier assembly 110' is to use varactor diodes or capacitor banks based on a lookup table to compensate for the phase distortion of the unit PA unit 204 at the driver stage 202. However, additional memory and processor power can be used, which increases cost and reduces overall power efficiency, especially for wideband modulated signals (>20MHz). Therefore, the unit PA unit assembly 204 or output power stage 204 includes a self-compensating function (e.g., a suppression component) relative to nonlinear capacitance changes without introducing additional components: as power decreases, the bias of the unit PA unit 204 in the off state (back-off mode) can be adjusted to minimize the overall drain capacitance change.

[0030] In one embodiment, as the voltage swing at the drain nodes of M3 and M4 increases (PA power increases), the cascode transistors (M3 and M4) or thick oxide transistors operate for a longer time in the transistor region or operating mode, where each capacitor Cgd exhibits a larger capacitance (WxCov + WxLxCgg / 2) than the capacitance (WxCov) of each Cgd operating in the saturation region or operating mode. In other words, when the output power of PA 110' decreases (fallback operating mode), the effective capacitance (Cdev) of PA 110' at the drain of the cascode transistors (M3 and M4) decreases.

[0031] In one embodiment, the output power network 204 can self-compensate for the phase distortion of PA 110' in power back-off mode due to reduced effective capacitance by utilizing the parasitic capacitance Cds of the cascode transistors (M3 and M4) via the suppression component 220, which includes transistors M1 and M2, without requiring additional components. The unit PA component 204 can compensate for or mitigate phase distortion using its own components, rather than compensating for phase distortion of PA 110' at the driver stage, for example, by using varactor diodes or capacitor banks and lookup tables. The suppression component utilizes the inherent parasitic capacitance of the power amplifier component 220 to compensate for nonlinear capacitance changes at the output.

[0032] For example, each of the unit PA units 204 may include the corresponding unit PA units Y1-Y2. n-1 They can operate in both power-on and power-off modes depending on the changes. Thus, during operation, the unit PA cells Y1-Y2 with transistors M3 and M4... n-1 The power increase can fluctuate between the power-on phase or operating mode and the power-off phase or operating mode. The power-on mode can include a saturation mode, for example, where the PA and any number of output power networks Y1-Y2 of the output power stage 204... n-1 It is fully powered.

[0033] Furthermore, the power-down phase or mode can be a rollback mode, in which power is reduced or the output power network of the unit PA unit component 204 is de-energized or shut down. Parasitic capacitance is still generated during this operation, but this parasitic capacitance does not affect the output because the capacitor Cds can effectively float during the rollback operation mode since both thin oxide transistors M1 and M2 are turned off.

[0034] Suppression component 220 may include, for example, transistors M1 and M2. Suppression component 220 is operable to adjust the bias of transistors M1, M2, M3, and M4. Across Y1-Y2 n-1 The capacitors or capacitor cells Cds at the drain and source of the thick oxide transistors M3 and M4 in each unit PA cell assembly 204 are manipulated to minimize the total capacitance variation in the backoff power mode. The parasitic capacitance of PA 110' or one or more unit PA cells 204 can have nonlinear behavior relative to the power level, where the effective parasitic capacitance decreases as the power decreases. Therefore, the parasitic capacitance varies between different operating modes, namely backoff mode and saturation operation mode. A self-suppressing or self-compensating bias scheme generated by the suppression component can linearize the nonlinear parasitic capacitance behavior of PA 110'. Thus, the suppression component 220 achieves continuous baseline operation and minimizes the total capacitance variation to reduce phase distortion caused by the variation of parasitic capacitance between different modes of normal operation. (Refer to below) Figure 3 Additional details of the operation of the suppression component 220 are shown and described.

[0035] In another embodiment, the output passive network 206 (such as an impedance matching network) can be implemented using a single transformer. The single transformer for the output passive network 206 includes two inductors (one for magnetizing inductance and the other for leakage inductance, parasitic capacitance) and absorbs the power amplifier output capacitor to provide a practical impedance transformation or flat phase response to PA110' along a wide bandwidth (e.g., about 2.4 GHz to about 5.5 GHz, or other broadband). For example, the output passive network 206 can operate as a multiresonant network to perform impedance matching, power combining, even-harmonic suppression, and differential-to-single-ended conversion across a wide frequency range (one octave) using the coverage area of ​​a single transformer. The output passive network 206 can also generate or provide a flat phase response across a wide bandwidth or at least two different operating frequency bands (e.g., about 2 GHz and 5.5 GHz), such that variations in output capacitance due to the nonlinear capacitance of the power amplifier cause minimal signal phase changes. The flat phase response generated by the output passive network 206 can effectively suppress AM-PM distortion. This enables excellent AM-PM performance across a wide bandwidth.

[0036] One advantage of PA 110' is that it utilizes the inherent parasitic capacitance of the PA transistors (e.g., M3 and M4) to compensate for or linearize nonlinear capacitance variations, providing an efficient and compact solution when the PA operates in back-off mode or alternates between back-off and saturation modes. Compared to multi-band PAs using separate output matching networks, the proposed multi-band PA output stage utilizes only a compact passive transformer as the matching resonant network component 206, which can provide parallel output power combination, output impedance matching, even-order harmonic suppression, and differential-to-single-ended conversion across a wide bandwidth without requiring any lossy tunable passive components or switches. Another advantage is that PA 110' can significantly reduce the transmitter area by 2x or more and maximize PA efficiency. Furthermore, for example, the proposed PA 110' architecture achieves excellent AM-PM characteristics (<3°), power-added efficiency (PAE) of approximately 30–40%, error vector amplitude (EVM) of 2.05%, and 256 quadrature amplitude modulation (QAM), and can cover a wide frequency range (1:2 range) in an ultra-compact region, which is advanced performance in CMOS PAs.

[0037] refer to Figure 3 , Figure 3 Another example of a unit PA unit assembly 204 for a PA according to the described aspects or embodiments is shown. Furthermore, the PA assembly 204 or PA 110' discussed herein is not limited to a digital PA and can also be used with an analog PA, or a combination of a digital PA and an analog PA. The example unit PA unit assembly 204 depicts output power networks Y1-Y2 in two different power stages that can operate alternately or change operation during different power levels of operation of PA 110 or 200. n-1 The operation.

[0038] In one embodiment, the unit PA unit component 204' is operable to generate self-compensation or self-suppression of nonlinearities caused by parasitic capacitances resulting from different power-on and power-off modes (back-off or saturation modes). For example, the first power stage includes a saturation (active) operating mode 302, wherein the output power network Y1-Y2 of the unit PA unit component 204 n-1 Operating at full or complete power above the threshold voltage, causing network Y1-Y2 n-1 Transistors M3 and M4 in any of the networks are operational and have already created channels for current. This allows current to flow between the drain and source. Because the drain voltage is higher than the source voltage, the electron current diffuses, and conduction is not through narrower channels but through wider channels, with the two-dimensional or three-dimensional current distribution extending far from the interface and deeper into the substrate.

[0039] Conversely, when the power is normally reduced and the power supply is backed off such that transistors M3 and M4 are turned off or in the subthreshold mode, the fallback mode 304 of operation occurs. Although the current between the drain and source should ideally be zero when the transistor is used as a turn-off switch, there may be a weak inversion current, sometimes referred to as subthreshold leakage. The subthreshold I-V curve can exponentially depend on the threshold voltage, thereby introducing a strong dependence on any manufacturing variations that affect the threshold voltage (e.g., variations in oxide thickness, junction depth, or body doping, which change the degree of barrier lowering introduced by the drain). The resulting sensitivity to manufacturing variations can complicate the optimization of leakage and performance.

[0040] The unit PA cell 204 may include an n-bit binary weighted power cell having a differential cascode amplifier topology. Figure 3 A digital switched PA scheme is shown that is operable to turn on / off the binary weighted unit power amplifier cells Y1 - Y2 n-1 to control the amplitude. For example, when the unit PA cell (Y1) is turned on in the saturation / power mode 302, the cascode transistors (M3 and M4) may be biased at a high voltage (above the threshold voltage or saturation power level) and the thin gate transistors (M1 and M2) may be differentially driven ( Figure 2 by the differential pulses 306 and 308 of the driver stage 202). When the unit PA cell (Y1) is turned off below the threshold voltage or in the fallback mode 304, the cascode transistors (M3 and M4) may be biased at a low voltage (below the threshold voltage, e.g., LOW < V TH ). However, AM - PM distortion may exist in response to the thin gate transistors (M1 and M2) being turned off.

[0041] In one embodiment, the suppression component 220 is operable to account for the Cds of the cascode transistors (M3 and M4) when the unit PA cell 204 is turned off (or when the power is reduced in the fallback mode). During the fallback operation mode, only a small portion of the Cds is loaded at the drain because the thin gate transistors are fully turned off and one terminal of the Cgd effectively floats. When the power cell is turned off or in the fallback mode 304, the cascode transistors (M3 and M4) may be biased at a lower voltage below the threshold voltage (<Vth) for weekly conducting, while the thin gate transistors (M1 and M2) are now fully turned on or fully powered as the suppression component 220. Thus, the Cds is fully loaded at the drain of the cascode transistors (M3 and M4), enabling an increase in the off-state capacitance. Accordingly, the cascode transistors (M3 and M4) are still biased in the subthreshold region (<Vth) to minimize leakage in the off-state 304.

[0042] Therefore, the suppression component 220 can provide additional capacitance that can compensate for the decrease in capacitance of Cgd during power back-off of the PA, without requiring additional control bits for self-suppression or compensation schemes when the power unit is off (when PA power decreases and effective capacitance Cdev decreases). In other words, the total capacitance change causing AM-PM distortion is reduced, and the unit PA unit compensates for or suppresses nonlinearity by coupling Cds to ground during the power-down or back-off operation phase to increase parasitic capacitance. This compensation scheme can be implemented without adding additional capacitors or capacitor assemblies.

[0043] On the other hand, the suppression component 220 may include detection components 310 and 312, which may include a set of switches or inverters 312 and 314, configured to detect a back-off power operating mode from a saturated power operating mode based on the power level of a first plurality of transistors. Based on the detection of the power level, inverters 312 or 314 may operate the suppression component 220 to mitigate the nonlinear behavior of the PA component 204', wherein the effective parasitic capacitance decreases as the power decreases, and a self-compensating bias operation linearizes the nonlinear parasitic capacitance of the PA component 204'.

[0044] refer to Figure 4 , Figure 4 Example results of the simulated self-compensation scheme and output passive network based on the described aspects are shown. The characteristics of the PA 110' capacitor behavior can be seen from simulation graph 400. Curve 402 shows the difference in total capacitance between PA 110' during operation when the transmission is processed by the suppression component 220 using a self-suppression or compensation scheme, in the case of unit PA cell off, low power, or backoff. Curve 404 shows the difference in total capacitance between PA 110' during operation when the transmission is not processed by the suppression component 220 using a self-suppression or compensation scheme, in the case of unit PA cell off or backoff. Thus, Figure 4 The diagram shows that the effective capacitance (Cdev) of the analog PA 110' at the drain of the cascode transistors (M3 and M4) decreases to approximately 0.4 pF with variations in the self-compensation scheme of the suppression component 220, whereas without the PA scheme, a variation of approximately 1.31 pF could result in an output power range from 10 mW to 640 mWm, which is a source or cause of AM-PM distortion. Therefore, reducing the total capacitance variation by the suppression component 220 self-compensates for the nonlinear capacitance and otherwise substantially reduces the total capacitance variation between operating modes to nearly half of the total capacitance during the fallback mode. For example, across a frequency range of 2.4 GHz to 6 GHz (which covers most commercial standard bands), AM-PM distortion can be further minimized to below 3°.

[0045] refer to Figure 5 , Figure 5 It shows that, together with Figure 6 Examples of the output passive network 206' described together, where Figure 6 Output simulation 600 is shown, illustrating the effect of the operation of the output passive network 206'. The output passive network 206' can be operated as a multi-order resonant network providing a flat phase response, wherein the slope of the phase response is approximately zero (≈0) over a wide / wide frequency range.

[0046] The output passive network 206' may include multiple inductors and capacitors, which are configured to supply power to PA 110' or unit PA units Y1-Y2 over a wide / wide bandwidth. n-1 The combination provides either a practical impedance or a flat phase response. A flat phase response is shown as the second stage (2) of the analog 600. For example, the output passive network 206' may include a second-order resonant network that can resonate at two (or more) different frequencies (e.g., 2 GHz and 5.8 GHz). Due to the dual (or multiple) resonances of the output passive network 206', a flat phase response is achieved across a frequency range within at least two resonant frequencies. Figure 6 The flat phase region (2) indicates the minimum phase change relative to the change in the applied capacitance (Cdev). Thus, Figure 5 and Figure 6 A schematic diagram and simulation results of our proposed dual-resonant network (e.g., resonating at 2 GHz and 5.8 GHz) are shown, clearly demonstrating the flat phase response between approximately 2 GHz and 5.8 GHz. Other ranges can be envisioned, as will be appreciated by those skilled in the art.

[0047] For example, different inductors Lpx(1-k) in the output passive network 206' 2 ) and Lpxk 2 A single transformer 500 can be formed or implemented for high-order LC matching networks, producing a robust or flat phase response to the nonlinear capacitance of PA 110'. For example, the inductors and capacitors of the output passive network can be implemented by a single transformer 500 by utilizing the parasitic components of the physical transformer and the nonlinear parasitic capacitance of PA component 204.

[0048] For example, a single transformer 500 can be further operated to efficiently combine from Figure 2 PA component 204 unit PA units Y1-Y2 n-1The power can be efficiently transferred to the antenna 106 or the load, for example, while AM-PM distortion is suppressed through the output passive network 206'. For example, since PA 110' provides different capacitances at different power levels, the output passive network 206' of PA 110' is operable to make the phase response of the output passive network robust to capacitance variations by utilizing multiresonant operation over a wide operating bandwidth.

[0049] Figure 6 Curve 602 can represent a virtual value or a capacitance curve. Curve 604 can represent a real value or an inductance curve. For example, curve 606 can represent a phase response curve with a flat response in a portion (2) of a wider frequency operating range. Typically, output passive networks based on first-order LC resonances can be widely used in narrow-band power amplifiers. However, the phase response of a first-order resonant network can be susceptible to variations in the applied capacitance (Cdev), as it directly alters the resonant frequency, resulting in undesirable phase shifts / distortions. Therefore, the slope of the phase response will depend on the applied Q and the phase distortion due to the variation in Cdev, and in this case, it can be proportional to the slope of the phase response. In contrast, the output passive network 206' produces a flat phase response over a frequency range of at least two of the different resonant frequencies of the signal across different operating bands. This provides a robust phase response against nonlinear capacitance variations in PA 110'.

[0050] While the methods described herein are shown and described herein as a series of actions or events, it will be understood that the order in which these actions or events are shown should not be interpreted in a limiting sense. For example, some actions may occur in a different order and / or simultaneously with other actions or events besides those shown and / or described herein. Furthermore, not all of the shown actions may be required to implement one or more aspects or embodiments described herein. Additionally, one or more actions depicted herein may be performed in one or more separate actions and / or phases.

[0051] refer to Figure 7 , Figure 7 An example method is shown for utilizing a PA circuit with AM-PM distortion compensation via a passive network output from a communication device (e.g., a mobile device or user equipment). Method 700 begins at 702, providing a power signal along the transmitter path via a power amplifier.

[0052] At 704, the method includes combining power signals via an output passive network and suppressing amplitude modulation to phase modulation (am-pm) distortion based on whether the power amplifier is operating in back-off power mode or saturation power mode. Combining power signals via the output passive network includes combining power signals from a unit power amplifier and providing optimal impedance to the power amplifier with a wide bandwidth through a single transformer.

[0053] The method may also include adjusting the bias of the capacitor unit in the unit power amplifier unit of the power amplifier to minimize the total capacitance variation in the backoff power mode by utilizing the inherent parasitic capacitance of the power amplifier components from the nonlinear capacitance variation at the compensation output.

[0054] The method may include generating a flat phase response across a frequency range of at least two of the different resonant frequencies of the output passive network 206.

[0055] Providing a power signal along the transmitter path may further include alternating or sequentially operating in a back-off power mode and a saturation power mode, increasing the capacitance of a first plurality of transistors at the corresponding drain terminal in the back-off power mode, and decreasing that capacitance (e.g., active or differential capacitance) in the saturation power mode. A second plurality of transistors with smaller gates than the first plurality of transistors may be provided and coupled to the drain of the first plurality of transistors, which operate in a voltage region below a threshold.

[0056] To provide additional context for the various aspects of the disclosed topic, Figure 8 An access device, user equipment (e.g., mobile device, communication device, personal digital assistant, etc.) or software 800 is shown in connection with a network (e.g., base station, wireless access point, femtocell access point, etc.) that can access features or aspects of the disclosed aspects that can be realized and / or utilized.

[0057] User equipment or mobile communication device 800 can be used with one or more aspects of the converter system or device described in accordance with various aspects of this document. Mobile communication device 800 includes, for example, a digital baseband processor 802 that can be coupled to a data storage device or memory 803, a front-end 804 (e.g., an RF front-end, an acoustic front-end, or other similar front-end), and antennas 8061 to 806 for connection to multiple antennas. k Multiple antenna ports 807 (where k is a positive integer). Antennas 8061 to 806. kSignals can be received from or transmitted to one or more wireless devices (e.g., access points, access terminals, wireless ports, routers, etc.) that can operate within a radio access network or other communication network generated via network devices (not shown). User equipment 800 can be an RF device for transmitting radio frequency (RF) signals, an acoustic device for transmitting acoustic signals, or any other signal transmission device, such as a computer, personal digital assistant, mobile phone or smartphone, tablet PC, modem, laptop, router, switch, repeater, PC, network device, base station, or similar device operable to communicate with a network or other devices according to one or more different communication protocols or standards.

[0058] The front end 804 may include a communication platform with electronic components and associated circuitry that provide processing, manipulation, or shaping of signals transmitted or received via one or more receivers or transmitters 808, multiplexing / demultiplexing components 812, and modulation and demodulation components 814. The front end 804 is, for example, coupled to a digital baseband processor 802 and a set of antenna ports 807, wherein antennas 8061 to 806... k It can be part of the front end. In one aspect, mobile communication device 800 may include PA component / system 810 according to the embodiments / aspects described herein.

[0059] User equipment 800 may also include a processor 802 or a controller operable to provide or control one or more components of mobile device 800. For example, according to aspects of this disclosure, processor 802 may at least partially assign functionality to substantially any electronic component within mobile communication device 800. As an example, the processor may be configured to at least partially execute an executable file that controls various modes or components of PA component / system 810 (e.g., system 110, 200, 110, 110', or 204).

[0060] Processor 802 is operable to enable mobile communication device 800 to process data (e.g., symbols, bits, or chips) for multiplexing / demultiplexing using multiplexing / demultiplexing component 812 or for modulation / demodulation via modulation / demodulation component 814, such as implementing direct and inverse fast Fourier transforms, selecting modulation rates, selecting data packet formats, inter-packet timing, etc. Memory 803 may store data structures (e.g., metadata), one or more code structures (e.g., modules, objects, classes, procedures, etc.) or instructions, network or device information (e.g., policies and specifications), attachment protocols, code sequences for scrambling, spread and pilot (e.g., one or more reference signals) transmissions, frequency offsets, cell IDs, and other data for detecting and identifying various characteristics related to the RF input signal, power output, or other signal components during power generation.

[0061] The processor 802 is functionally and / or communicatively coupled (e.g., via a memory bus) to the memory 803 to store or retrieve information required for operation, and at least in part to provide functionality to the communication platform or front end 804, PA component / system 810, and virtually any other operational aspect described herein.

[0062] Examples in this document may include the following subjects: methods, means for performing actions or blocks of methods, and at least one machine-readable medium including executable instructions that, when executed by a machine (e.g., a processor having memory, etc.), cause the machine to perform actions for concurrent communication using multiple communication technologies according to the described embodiments and examples.

[0063] Example 1 is a communication system comprising: a power amplifier including a plurality of unit power amplifier units configured to provide a power signal along a transmitter path; and an output passive network component configured to combine the power signals from the plurality of unit power amplifier units and suppress amplitude modulation to phase modulation (AM-PM) distortion.

[0064] Example 2 includes the subject of Example 1, and also includes: a detection component configured to detect a backoff power mode from a saturated power mode based on the output power level.

[0065] Example 3 includes the subject matter of any of Examples 1-2, including or omitting any elements, and further includes: a suppression component configured to adjust the bias of the unit power amplifier unit of the power amplifier to minimize the overall capacitance variation over the full operating power range.

[0066] Example 4 includes the subject matter of any of Examples 1-3, including or omitting any elements, wherein the suppression component is also configured to utilize the inherent parasitic capacitance of the power amplifier from nonlinear capacitance changes at the compensation output.

[0067] Example 5 includes the subject matter of any of Examples 1-4, including or omitting any elements, wherein the output passive network component includes a matching network configured to utilize a single transformer to generate output impedance matching operation by using parasitic components of a single transformer to generate broadband impedance transformation and suppress AM-PM distortion.

[0068] Example 6 includes the subject matter of any of Examples 1-5, including or omitting any components, wherein the output passive network component includes multiple capacitors and inductors, configured to provide a practical impedance with a flat phase response to the power amplifier along a wide bandwidth to suppress AM-PM distortion.

[0069] Example 7 includes the subject matter of any of Examples 1-6, including or omitting any components, wherein multiple capacitors and inductors of the output passive network components are implemented by a single transformer by utilizing the parasitic components of a single transformer and the nonlinear parasitic capacitance of the power amplifier.

[0070] Example 8 includes the subject matter of any of Examples 1-7, including or omitting any elements, wherein the matching network is further configured to produce a flat phase response across a frequency range of at least two of the different resonant frequencies of the matching network, wherein the matching network includes a robust phase response to nonlinear capacitance variations of the power amplifier.

[0071] Example 9 is a mobile communication device comprising: a power amplifier including a plurality of unit power amplifier units configured to provide a power signal to a signal processing path, including an output power stage; and an output passive network of the output power stage configured to combine the power signal and suppress amplitude modulation-phase modulation (AM-PM) distortion from the saturation power operation mode in a back-off power operation mode.

[0072] Example 10 includes the subject matter of Example 9, including or omitting any elements, wherein a plurality of unity power amplifier units provide a power signal for a desired power to an output passive network, wherein the power amplifier includes a parasitic capacitance having nonlinear behavior relative to the power level, wherein the parasitic capacitance decreases as the power decreases, and a suppression component is configured to provide a self-compensating bias scheme for linearizing the parasitic capacitance of the power amplifier.

[0073] Example 11 includes the subject matter of any of Examples 9-10, including or omitting any elements, and further includes: a suppression component configured to adjust the bias of the capacitor unit in the unity power amplifier unit among a plurality of unity power amplifier units to linearize the nonlinear behavior of the parasitic capacitance of the unity power amplifier unit.

[0074] Example 12 includes the subject matter of any of Examples 9-11, including or omitting any elements, wherein the suppression component is further configured to compensate for the reduction in effective capacitance of the power amplifier in back-off power operation mode by using the parasitic capacitance of the first plurality of transistors via a second plurality of transistors coupled to the drain terminals of the first plurality of transistors.

[0075] Example 13 includes the subject matter of any of Examples 9-12, including or omitting any elements, wherein, in the backoff power operation mode, the first plurality of transistors of the power amplifier are configured to include a lower voltage, and in the saturation power operation mode, the first plurality of transistors include a saturation voltage.

[0076] Example 14 includes the subject matter of any of Examples 9-13, including or omitting any elements, and further includes: a suppression component including a second plurality of transistors coupled to the first plurality of transistors, the second plurality of transistors being configured to be fully powered in a back-off power operation mode; and a detection component including a set of switches configured to detect a back-off power operation mode from a saturated power operation mode based on the power level of the first plurality of transistors.

[0077] Example 15 includes the subject matter of any of Examples 9-14, including or omitting any elements, wherein the suppression component is configured to bias a first plurality of transistors of the output power stage while operating below an operating voltage threshold during a back-off power operation mode.

[0078] Example 16 includes the subject matter of any of Examples 9-15, including or omitting any elements, wherein the output passive network component includes a matching network configured to utilize the single transformer to generate impedance matching operation by using parasitic components of a single transformer to generate broadband impedance transformation and suppress AM-PM distortion.

[0079] Example 17 includes the subject matter of any of Examples 9-16, including or omitting any elements, wherein the matching network is also configured to resonate at different resonant frequencies and produce a flat phase response across a frequency range of at least two of the different resonant frequencies.

[0080] Example 18 includes the subject matter of any of Examples 9-17, including or omitting any elements, wherein the power amplifier includes a plurality of unit power amplifier units configured to provide power signals along the signal processing path according to different operating frequency bands.

[0081] Example 19 is a method for a communication system, comprising: providing a power signal along a transmitter path via a power amplifier; and combining the power signal via an output passive network, and suppressing amplitude modulation to phase modulation (AM-PM) distortion based on whether the power amplifier is operating in back-off power mode or saturation power mode.

[0082] Example 20 includes the subject matter of Example 19, including or omitting any elements, and further includes: adjusting the bias of the capacitor unit in the unit power amplifier unit of the power amplifier to minimize the overall capacitance variation in the backoff power mode by utilizing the inherent parasitic capacitance of the power amplifier components to compensate for the nonlinear capacitance variation at the output.

[0083] Example 21 includes the subject matter of any of Examples 19-20, including or omitting any elements, wherein combining power signals via an output passive network includes combining power signals from a unit power amplifier unit and providing optimal impedance to the power amplifier over a wide bandwidth via a single transformer.

[0084] Example 22 includes the subject matter of any of Examples 19-21, including or omitting any elements, and further includes: producing a flat phase response across a frequency range of at least two of the different resonant frequencies of the output passive network.

[0085] Example 23 includes the subject matter of any of Examples 19-22, including or omitting any elements, wherein providing a power signal along the transmitter path includes alternating operation in a back-off power mode and a saturation power mode, and in the back-off power mode, increasing the capacitance of the first plurality of transistors at the corresponding drain terminal, and decreasing the capacitance in the saturation power mode.

[0086] Example 24 includes the subject matter of any of Examples 19-23, including or omitting any elements, and further includes: powering a second plurality of transistors having a smaller gate than the first plurality of transistors and being coupled at the drain of the first plurality of transistors, which operate in a voltage region below a threshold.

[0087] The above description of the embodiments disclosed in this subject matter (including the description in the abstract) is not intended to be exhaustive or to limit the disclosed embodiments to the precise forms disclosed. Although specific embodiments and examples have been described herein for illustrative purposes, various modifications can be made within the scope of the various embodiments and examples, as will be appreciated by those skilled in the art.

[0088] In this regard, while the disclosed subject matter has been described in conjunction with various embodiments and corresponding drawings, it should be understood where appropriate that other similar embodiments may be used, or modifications and additions may be made to the described embodiments to perform the same, similar, or alternative functions of the disclosed subject matter without departing from it. Therefore, the disclosed subject matter should not be limited to any single embodiment described herein, but should be interpreted within the breadth and scope of the appended claims.

[0089] In particular, regarding the various functions performed by the aforementioned components or structures (components, devices, circuits, systems, etc.), unless otherwise stated, the terminology used to describe these components (including references to "device") is intended to correspond to any component or structure that performs the specified function of the described component (e.g., functionally equivalent), even if it is not structurally equivalent to the disclosed structure that performs the function in the exemplary embodiments of the invention shown. Furthermore, although a particular feature may be disclosed only for one of several implementations, such feature may be combined with one or more other features of other implementations, as may be desired and advantageous for any given or particular application.

Claims

1. An apparatus for amplifying radio frequency signals, comprising: Multiple differential amplifier units are coupled to the output passive network; At least one of the plurality of differential amplifier units includes a first pair of common-source cascode transistors and a second pair of transistors; wherein the second pair of transistors includes a gate with a smaller size than the first pair of common-source cascode transistors. Digital circuits, which can be configured to turn on or off at least one pair of common-source cascode transistors; and The driver stage is used to generate drive signals for the plurality of differential amplifier units.

2. The apparatus according to claim 1, wherein, The driver level includes one or more driver level units.

3. The apparatus according to claim 2, wherein, The driver stage unit includes one or more amplifiers.

4. The apparatus according to claim 2, wherein, The driver-level unit includes one or more comparators.

5. The apparatus according to claim 1, wherein, The digital circuitry is configured to control the differential amplifier unit by providing a bias signal to the gate of the transistor.

6. The apparatus according to claim 1, wherein, The digital circuitry is configured to control the differential amplifier unit by providing a voltage bias to the gate of the common-source cascode transistor.

7. The apparatus according to claim 1, wherein, The output passive network includes at least one transformer.

8. The apparatus according to claim 1, wherein, The output passive network includes at least one capacitor unit.

9. The apparatus according to claim 7, wherein, The transformer and the plurality of differential amplifier units are coupled in parallel to each other.

10. The apparatus according to claim 1, further comprising: A set of switches or inverters coupled to the second pair of transistors and configured to selectively enable the power level of the second pair of transistors via the digital circuitry and based on a threshold voltage.

11. The apparatus according to claim 1, wherein, The digital circuit is configured to turn on the at least one pair of cascode transistors by biasing them above a threshold voltage and to turn off the at least one pair of cascode transistors by biasing them below a threshold voltage.

12. The apparatus according to claim 1, wherein, The smaller size refers to a smaller gate width.

13. The apparatus according to claim 1, wherein, The digital circuitry can be configured to turn on or off a selected subset of the cascode transistor pairs of the differential amplifier unit.

14. The apparatus according to claim 1, wherein, The plurality of differential amplifier units are part of a power amplifier circuit.

15. A power amplifier for amplifying radio frequency signals in a mobile device, comprising: Multiple differential amplifier units are coupled to the output passive network; At least one of the plurality of differential amplifier units includes a first pair of cascode transistors and a second pair of transistors, wherein the second pair of transistors has a smaller size than the first pair of cascode transistors; Digital circuits, which can be configured to turn on or off at least one pair of common-source cascode transistors; and The driver stage is used to generate drive signals for the plurality of differential amplifier units.

16. A method for operating an apparatus for amplifying radio frequency signals, the apparatus having a plurality of differential amplifier units coupled to an output passive network, in, At least one of the plurality of differential amplifier units includes a first pair of cascode transistors and a second pair of transistors, wherein the second pair of transistors includes a gate with a smaller size than the first pair of cascode transistors, and the method includes: Provide a bias signal to the gate of the transistor; and A voltage bias is provided to the gate of the common-source cascode transistor.

17. The method of claim 16, further comprising: The power level of the transistor is selectively enabled based on a threshold voltage.

18. The method of claim 16, further comprising: Turn on or off a selected subset of the common-source cascode transistor pairs of the plurality of differential amplifier units.

19. The method of claim 16, further comprising: The cascode transistor is turned on based on a bias voltage higher than a threshold voltage, and The cascode transistor is disconnected based on a bias voltage below a threshold voltage.

20. A user equipment or mobile communication device, comprising means for amplifying radio frequency signals, the means comprising: Multiple differential amplifier units are coupled to the output passive network. At least one of the plurality of differential amplifier units includes a first pair of common-source cascode transistors and a second pair of transistors, wherein the second pair of transistors includes a gate with a smaller size than the first pair of common-source cascode transistors; Digital circuitry configured to turn on or off at least one pair of common-source cascode transistors; and The driver stage is used to generate drive signals for the plurality of differential amplifier units.

21. An apparatus for a power amplifier, comprising a multiresonant network assembly for: Using a single transformer to perform impedance matching, power combining, even-order harmonic suppression, and differential-to-single-ended conversion across a wide frequency range; and It provides a flat phase response across a wide bandwidth, so that changes in the output capacitance due to the nonlinear capacitance of the power amplifier cause minimal signal phase changes.

22. The apparatus according to claim 21, wherein, The wider frequency range includes one octave.

23. The apparatus according to claim 21, wherein, The single transformer includes two inductors, one for magnetizing inductance and the other for leakage inductance and parasitic capacitor.

24. The apparatus according to claim 21, wherein, The wide bandwidth ranges from approximately 2.4 GHz to approximately 5.5 GHz.

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