Adaptive biasing in power amplifier circuits

Abstract

The invention discloses adaptive biasing in a power amplifier circuit. The power amplifier circuit is configured to amplify a radio frequency (RF) signal based on a modulated voltage. Generally, the modulated voltage is generated based on a pre-established lookup table (LUT) that correlates an amplitude and a phase of the modulated voltage with a time-varying power envelope of the RF signal. In embodiments disclosed herein, an adaptive bias circuit may be dynamically activated to inject an adaptive bias current into a bias circuit in the power amplifier circuit to reshape amplitude-amplitude (AM / AM) and / or amplitude-phase (AM / PM) characteristics of the modulated voltage. Accordingly, it is possible to dynamically adjust AM / AM gain dispersion and / or improve a non-linear portion of the AM / PM characteristic of the modulation voltage, thereby improving the performance of the power amplifier circuit.

Description

[0001] Related applications

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 499,827, filed May 3, 2023, the disclosure of which is hereby incorporated herein by reference in its entirety. Technical Field

[0003] The technology disclosed herein generally relates to a power amplifier circuit. Background Technology

[0004] Mobile communication devices have become increasingly prevalent in modern society for providing wireless communication services. This widespread use is partly due to the numerous functions now integrated into these devices. The increased processing power in these devices means they have evolved from mere communication tools into sophisticated mobile multimedia hubs capable of enhancing user experience.

[0005] Compared to existing fourth-generation (4G) communication systems such as LTE, fifth-generation (5G-NR) wireless communication systems are widely regarded as a technological advancement, enabling significantly higher data throughput, improved coverage, enhanced signaling efficiency, and reduced latency. Today, mobile communication devices are typically configured to support both 4G and 5G wireless communication systems. Typically, mobile communication devices need to transmit and receive RF signals in the radio frequency (RF) spectrum, which is more susceptible to propagation attenuation and interference, potentially leading to a significant reduction in data throughput. To help mitigate propagation attenuation and maintain the desired data throughput, mobile communication devices typically employ power amplifiers to increase the output power of the RF signal before transmission.

[0006] Envelope tracking (ET) and average power tracking (APT) are power management techniques designed to improve the efficiency of power amplifiers. Specifically, the power amplifier is configured to amplify the RF signal based on a modulation voltage (ET voltage or APT voltage) that closely tracks the time-varying power envelope of the RF signal. It is understood that the closer the modulation voltage is to the amplitude and phase of the time-varying envelope, the better the power amplifier can perform, helping to improve the overall performance of mobile communication devices, such as adjacent channel leakage ratio (ACLR) and adjacent channel power ratio (ACPR). Summary of the Invention

[0007] The aspects disclosed in the detailed description include adaptive biasing in a power amplifier circuit. The power amplifier circuit is configured to amplify a radio frequency (RF) signal based on a modulated voltage. Typically, the modulated voltage is generated based on a pre-established lookup table (LUT) that correlates the amplitude and phase of the modulated voltage with the time-varying power envelope of the RF signal. In the embodiments disclosed herein, an adaptive biasing circuit can be dynamically activated to inject an adaptive bias current into the biasing circuitry of the power amplifier circuit, thereby reshaping the amplitude-amplitude (AM / AM) and / or amplitude-phase (AM / PM) characteristics of the modulated voltage. Therefore, it is possible to dynamically adjust the AM / AM gain dispersion and / or improve the nonlinear portion of the AM / PM characteristics of the modulated voltage, thereby improving the performance of the power amplifier circuit.

[0008] In one aspect, a power amplifier device is provided. The power amplifier device includes a current source. The current source is configured to generate a low-frequency current. The power amplifier device further includes a power amplifier circuit. The power amplifier circuit includes a bias circuit. The bias circuit is configured to generate a bias voltage based on the low-frequency current. The power amplifier circuit further includes an output stage. The output stage is biased by the bias voltage to amplify an RF signal based on a modulation voltage. The power amplifier device further includes an adaptive bias circuit. The adaptive bias circuit is coupled to the bias circuit. The adaptive bias circuit is configured to inject an adaptive bias current into the bias circuit to dynamically adjust one or more of the AM / AM and AM / PM characteristics of the modulation voltage.

[0009] In another aspect, a wireless device is provided. The wireless device includes a wireless transmitting circuit. The wireless transmitting circuit includes a power management integrated circuit (PMIC). The PMIC is configured to generate a modulation voltage based on a pre-established lookup table (LUT) that correlates a time-varying target voltage with the modulation voltage. The wireless transmitting circuit also includes a power amplifier device. The power amplifier device includes a current source. The current source is configured to generate a low-frequency current. The power amplifier device further includes a power amplifier circuit. The power amplifier circuit includes a bias circuit. The bias circuit is configured to generate a bias voltage based on the low-frequency current. The power amplifier circuit further includes an output stage. The output stage is biased by the bias voltage to amplify an RF signal based on the modulation voltage. The power amplifier device also includes an adaptive bias circuit. The adaptive bias circuit is coupled to the bias circuit. The adaptive bias circuit is configured to inject an adaptive bias current into the bias circuit to dynamically adjust one or more of the AM / AM and AM / PM characteristics of the modulation voltage.

[0010] In another aspect, a method for implementing adaptive bias in a power amplifier circuit is provided. The method includes generating a low-frequency current. The method further includes generating a bias voltage based on the low-frequency current. The method further includes biasing an output stage in the power amplifier circuit using the bias voltage, thereby amplifying an RF signal based on a modulation voltage. The method further includes injecting an adaptive bias current into the power amplifier circuit to dynamically adjust one or more of the AM / AM and AM / PM characteristics of the modulation voltage.

[0011] After reading the following detailed description in conjunction with the accompanying drawings, those skilled in the art will understand the scope of this disclosure and recognize its other aspects. Attached Figure Description

[0012] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate several aspects of this disclosure and, together with the specification, serve to explain the principles of this disclosure.

[0013] Figure 1 This is a schematic diagram of an exemplary existing wireless transmitting circuit, in which a power management integrated circuit (PMIC) generates a modulation voltage based on a pre-established lookup table (LUT);

[0014] Figure 2A and 2B It is provided by Figure 1 An exemplary graph illustrating the amplitude-amplitude (AM / AM) and amplitude-phase (AM / PM) characteristics of the modulation voltage generated by the PMIC in the PMIC.

[0015] Figure 3 This is a schematic diagram of an exemplary power amplifier device configured to adjust the AM / AM and / or AM / PM characteristics of a modulation voltage according to an embodiment of the present disclosure;

[0016] Figures 4A-4C It provides can be provided by Figure 3 A diagram illustrating exemplary improvements in AM / AM, AM / PM, and adjacent channel leakage ratio (ACLR) achieved by a power amplifier circuit;

[0017] Figure 5 It provides Figure 3 A diagram illustrating exemplary diagrams of the multiple gain dispersion regions that the power amplifier circuit can operate in;

[0018] Figure 6 This is a schematic diagram of an exemplary power amplifier device configured according to another embodiment of the present disclosure;

[0019] Figure 7 It can be configured to include Figure 3 and 6A schematic diagram of the wireless transmission circuit of a power amplifier device;

[0020] Figure 8 This is a schematic diagram of an exemplary communication device, in which the following can be provided: Figure 7 The wireless transmission circuit; and

[0021] Figure 9 It is used to implement Figure 3 and 6 A flowchart illustrating an exemplary process of adaptive biasing in a power amplifier device. Detailed Implementation

[0022] The embodiments described below illustrate the information necessary to enable those skilled in the art to practice the embodiments and demonstrate the best mode of practice. After reading the following description with reference to the accompanying drawings, those skilled in the art will understand the concepts of this disclosure and will appreciate the application of these concepts, which are not specifically set forth herein. It should be understood that these concepts and applications fall within the scope of this disclosure and the appended claims.

[0023] It will be understood that while terms such as first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish different elements. For example, a first element may be referred to as a second element without departing from the scope of this disclosure, and similarly, a second element may be referred to as a first element. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0024] It should be understood that when an element, such as a layer, region, or substrate, is referred to as "on another element" or "extending to another element," it may be directly located on or directly extended to the other element, or intermediate elements may be present. Conversely, when an element is referred to as "directly located on another element" or "directly extended to another element," no intermediate elements are present. Similarly, it should be understood that when an element, such as a layer, region, or substrate, is referred to as "on top of another element" or "extending over another element," it may be directly located on top of or directly extended over the other element, or intermediate elements may be present. Conversely, when an element is referred to as "directly located on top of another element" or "extending directly over another element," no intermediate elements are present. It will also be understood that when an element is referred to as "connected" or "coupled" to another element, it may be directly connected to or coupled to the other element, or intermediate elements may be present. Conversely, when an element is referred to as "directly connected" or "directly coupled" to another element, no intermediate elements are present.

[0025] For example, relative terms such as “below” or “above” or “upper” or “lower” or “horizontal” or “vertical” may be used herein to describe the relationship of one element, layer, or region to another element, layer, or region as shown in the figures. It should be understood that these terms, and those discussed above, are intended to include different orientations of the device other than those depicted in the figures.

[0026] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. As used herein, unless the context clearly indicates otherwise, the singular forms “a”, “an”, and “described” are also intended to include the plural forms. It should also be understood that, when used herein, the terms “comprises,” “comprising,” “includes,” and / or “including” specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0027] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It should be further understood that the terms used herein shall be interpreted as having the same meaning as in the context of this specification and related art, and shall not be interpreted in an idealized or overly formal sense unless expressly defined herein.

[0028] The aspects disclosed in the detailed description include adaptive biasing in a power amplifier circuit. The power amplifier circuit is configured to amplify a radio frequency (RF) signal based on a modulated voltage. Typically, the modulated voltage is generated based on a pre-established lookup table (LUT) that correlates the amplitude and phase of the modulated voltage with the time-varying power envelope of the RF signal. In the embodiments disclosed herein, an adaptive biasing circuit can be dynamically activated to inject an adaptive bias current into the biasing circuitry of the power amplifier circuit, thereby reshaping the amplitude-amplitude (AM / AM) and / or amplitude-phase (AM / PM) characteristics of the modulated voltage. Therefore, it is possible to dynamically adjust the AM / AM gain dispersion and / or improve the nonlinear portion of the AM / PM characteristics of the modulated voltage, thereby improving the performance of the power amplifier circuit.

[0029] From Figure 3 Before discussing the power amplifier circuit of this disclosure, first refer to... Figure 1 and 2A -2B provides a brief overview of existing wireless transmission circuitry to help establish the technical problem to be addressed by the embodiments of this disclosure.

[0030] Figure 1 This is a schematic diagram of an exemplary existing wireless transmitting circuit 10, in which a power management integrated circuit (PMIC) 12 is configured to generate a modulation voltage V according to a pre-established lookup table (LUT) 14. CC For example, envelope tracking (ET) voltage. Existing wireless transmitting circuitry 10 typically includes transceiver circuitry 16 and power amplifier circuitry 18. Power amplifier circuitry 18 is configured based on modulation voltage V. CC Amplify the RF signal 20 generated by the transceiver circuit 16.

[0031] The power amplifier circuit 18 typically includes an output stage 22 and a bias circuit 24. Additionally, the power amplifier circuit 18 may also include an input stage 26. If available, the output stage 22 and the input stage 26 are configured based on the modulation voltage V. CC The RF signal 20 is transferred from the input power P IN Amplified to output power P OUT .

[0032] Output stage 22 may include components based on bias voltage V BIAS Various transistors (not shown) are used in operation, such as bipolar junction transistors (BJTs) or heterojunction bipolar transistors (HBTs). Typically, the bias circuit 24 is configured based on a low-frequency current I supplied by an external current source 28. DC (For example, DC) Generate bias voltage V BIAS .

[0033] Transceiver circuit 16 is configured to generate a modulated target voltage V that closely tracks the input power in amplitude and phase. TGT The pre-established LUT 14 is typically pre-calibrated to modulate the target voltage V. TGT With modulation voltage V CC Related. In this respect, for the modulated target voltage V TGT Given the instantaneous value (or range of instantaneous values), PMIC 12 can simply retrieve a set of corresponding amplitude and phase values ​​from the pre-established LUT 14 and generate the modulation voltage V accordingly. CC .

[0034] Conventionally, based on the swept output power P OUT and modulation voltage V CC The so-called "waterfall" characterization is used to determine the pre-established LUT 14. Specific values ​​in the pre-established LUT 14 are typically based on the modulation voltage V. CC and output power P OUT The corresponding reference point (e.g., V) CC = 3.5 V or 3.8 V and P OUT= +10 dBm) and the target power amplifier compression point are calculated based on the waterfall characterization. Each entry in the pre-established LUT 14 is associated with the AM / AM characterization and the AM / PM characterization, which are respectively located in... Figure 2A and 2B As shown in the image.

[0035] Figure 2A This is a diagram illustrating the AM / AM characterization of a pre-established LUT 14. In this paper, the AM / AM characterization is determined by the output power P. OUT The constant gain 30 (also known as IsoGain) obtained by sweeping through the gain dispersion region 32 is represented. As shown in the figure, the gain dispersion region 32 is approximately four decibels (4 dB).

[0036] Figure 2B This is a graph illustrating the AM / PM characterization of a pre-established LUT 14. In this paper, the AM / PM characterization typically refers to the nonlinear region 34, where the AM / PM characteristic is the output power P. OUT The nonlinear function. As shown in the figure, when the output power P OUT When the nonlinear phase changes from 20 dBm to 35 dBm, the phase change is approximately ten degrees (10°).

[0037] Return to reference Figure 1 Conventionally, transceiver circuit 16 is configured to correct or at least mitigate nonlinear AM / PM characteristics via digital predistortion (DPD). It is understood that the greater the AM / PM variation in the nonlinear region 34, the more difficult it is to correct the nonlinear AM / PM characteristics via DPD, as the complexity coefficients involved in DPD increase significantly. Therefore, it is desirable to reduce the AM / PM variation in the nonlinear region 34 (i.e., to make...). Figure 2B Flattening the AM / PM curve in the curve helps reduce the complexity of DPD operations. Additionally, as an important factor of quality (FoM) in ET, it is also desirable to broaden the curve. Figure 2A The gain dispersion region 32 is defined in this context. In the context of this disclosure, reshaping the AM / AM characteristics refers to widening the gain dispersion region 32, while reshaping the AM / PM characteristics refers to flattening the AM / PM curve in the nonlinear region 34. Unfortunately, the modulation voltage V generated based on the pre-established LUT 14... CC Adjusting and / or shaping the AM / AM and AM / PM characteristics is virtually impossible. Therefore, the technical problem that needs to be solved is how to dynamically adjust the AM / AM characteristics to broaden the gain dispersion region 32 and reshape the AM / PM characteristics to help improve the effectiveness of the DPD, especially in the case of ET.

[0038] in this regard, Figure 3 It can be configured to adjust the modulation voltage V according to one embodiment of the present disclosure.CC A schematic diagram of an exemplary power amplifier device 35 with AM / AM and / or AM / PM characteristics. In a non-limiting example, the modulation voltage V CC This can be the ET voltage. In this document, the power amplifier device 35 includes a power amplifier circuit 36. In an embodiment, the power amplifier circuit 36 ​​includes an output stage 38, a bias circuit 40, and may also include an input stage 42. The output stage 38 is biased by a voltage V. BIAS Bias, and the bias circuit 40 is configured to be based on a low-frequency current I provided by an external current source 44. DC (For example, DC) Generate bias voltage V BIAS If available, output stage 38 and input stage 42 are configured based on the modulation voltage V. CC The RF signal 46 is transferred from the input power P IN Amplified to output power P OUT .

[0039] and Figure 1 Similar to the existing wireless transmitting circuit 10, the modulation voltage V CC It can be generated by PMIC 12 based on a pre-established LUT 14. Therefore, the modulation voltage V CC It will inherently exhibit AM / AM and AM / PM characteristics, such as Figure 2A and 2B As shown in the image.

[0040] In this regard, to address the technical problems associated with the existing wireless transmitting circuit 10, the power amplifier circuit 36 ​​is configured herein to further include an adaptive bias circuit 48. The adaptive bias circuit 48 is configured to apply an adaptive bias current I... BIAS Injected into bias circuit 40 to dynamically adjust modulation voltage V CC One or more inherent characteristics (e.g., AM / AM characteristics and / or AM / PM characteristics). Therefore, as will be discussed later... Figures 4A-4C As shown, the power amplifier circuit 36 ​​can provide significant improvements in AM / AM gain dispersion, nonlinear phase change and ACLR performance.

[0041] In an embodiment, as an example, the adaptive bias circuit 48 includes a bias transistor 50, which may be an HBT. The bias transistor 50 has a base (B), a collector (C), and an emitter (E). The base (B) is configured to be connected via a first bias resistor R. AB1 Received modulation voltage V CC The first bias resistor can be a fixed resistor or an adjustable resistor. The base (B) is also connected via a bias capacitor C. AB Coupled to ground (GND). In the embodiment, the bias capacitor C... ABIt can filter out the modulation voltage V CC The residual RF component in the electrode. The collector (C) is coupled to the base (B).

[0042] The bias circuit 40 includes a pair of transistors 52 and 54, each transistor having a corresponding base (B), a corresponding collector (C), and a corresponding emitter (E). The collector (C) of transistor 52 is coupled to an external current source 44 via a voltage divider network 56. The voltage divider network 56 is coupled to the external current source 44 to receive a low-frequency current I. DC and the corresponding low-frequency voltage V DC The output is to the collector (C) of transistor 52. The emitter (E) of transistor 52 is coupled to the collector (C) of transistor 54, which is further coupled to the base (B) of transistor 54. The emitter (E) of transistor 54 is coupled to ground (GND). In an embodiment, the emitter (E) of bias transistor 50 is configured to be connected via a second bias resistor R. AB2 Bias current I BIAS The output is given to the base (B) of transistor 54. It is worth noting that the bias circuit 40 may include additional components such as transistors, resistors, capacitors, and / or voltage suppliers to generate the bias voltage V. BIAS For the sake of simplicity, these additional components have been omitted from this article.

[0043] In the adaptive bias circuit 48, the base (B) of the bias transistor 50 can be considered as being modulated by the modulation voltage V. CC Bias. In a non-limiting example, transistor 54 in bias circuit 40 biases the emitter voltage V at the emitter (E) of transistor 50. E It is set to approximately 1.25 V. In this respect, when the modulation voltage V... CC When the threshold voltage of bias transistor 50 is greater than or equal to that of bias transistor 50, bias transistor 50 (and therefore adaptive bias circuit 48) will automatically turn on (i.e., activate). In contrast, when the modulation voltage V... CC When the voltage drops below the threshold voltage of the bias transistor 50, the bias transistor 50 (and therefore the adaptive bias circuit 48) will automatically turn off (i.e., deactivate).

[0044] In an alternative embodiment, the bias transistor 50 can be replaced by a Schottky diode. Therefore, the adaptive bias circuit 48 will adjust the modulation voltage V. CC Automatically activated at approximately 2 V or higher, and at modulation voltage V CC Deactivated at voltages below 2 V. In another alternative embodiment, bias transistor 50 can be connected to a Schottky diode. Therefore, adaptive bias circuit 48 will activate at modulation voltage V. CC Automatically activated at approximately 3.2 V or higher, and at a modulation voltage V.CC Deactivate when the voltage is below 3.2 V.

[0045] The first bias resistor R can be adjusted statically or dynamically. AB1 Second bias resistor R AB2 To control the bias current I to be injected into the bias circuit 40 BIAS The amount. In other words, the first bias resistor R can be adjusted. AB1 and / or the second bias resistor R AB2 To control the bias current I BIAS The slope (i.e., relative to the modulation voltage V) CC (the rate of change). In a preferred embodiment, the first bias resistor R can be adjusted. AB1 To control the bias current I BIAS The slope of the second bias resistor R AB2 This can be used to maintain a large resistance to minimize leakage and noise injection in the bias circuit 40. Given the bias current I... BIAS Only by modulation voltage V CC Threshold voltage of bias transistor 50, first bias resistor R AB1 and / or the second bias resistor R AB2 Drive, bias current I BIAS Independent of the low-frequency current I supplied by the external current source 44 DC .

[0046] Power amplifier circuit 36 ​​can provide superior performance in many aspects. Figure 1 Significant improvements over the existing wireless transmission circuit 10. Figures 4A-4C It provides can be provided by Figure 3 A diagram illustrating an exemplary improvement in AM / AM, AM / PM, and adjacent channel leakage ratio (ACLR) implemented by the power amplifier circuit 36.

[0047] like Figure 4A As shown, by biasing current I BIAS Dynamically injected into the bias circuit 40, the gain dispersion region 32 from Figure 2A The approximately 4 dB widening in the original text has been increased to approximately 6 dB in this paper. For example... Figure 4B As shown, the nonlinear phase change in nonlinear region 34 originates from... Figure 2B The angle decreased from approximately 10° in the original text to approximately 7° in this paper. For example... Figure 4C As shown, the power amplifier circuit 36 ​​is able to reduce the ACLR to approximately -41 dBm. Therefore, by adding the adaptive bias circuit 48, it is possible to solve the problem related to... Figure 1 Technical problems associated with the existing wireless transmission circuit 10.

[0048] As previously mentioned, the adaptive bias circuit 48 can be configured to turn on and off based on different threshold voltages. This makes it possible for the power amplifier circuit 36 ​​to operate in different gain dispersion regions. Figure 5 This is a diagram illustrating an exemplary diagram of multiple gain dispersion regions GD1, GD2 that the power amplifier circuit 36 ​​of Figure 2 can be configured to operate.

[0049] In this paper, the gain dispersion region GD1 is determined by the modulation voltage V. CC The gain difference between 2.5 V and 5 V is defined, and the gain dispersion region GD2 is defined by the modulation voltage V. CC The gain difference between 1 V and 3.5 V is limited. Studies have shown that, using the adaptive bias circuit 48, the power amplifier circuit 36 ​​can operate with satisfactory performance in the gain dispersion regions GD1 and GD2. In particular, the power amplifier circuit 36 ​​can reduce AM / AM distortion from 1.5 dB to less than 1 dB in the gain dispersion region GD1.

[0050] Return to reference Figure 3 Alternatively, instead of incorporating the adaptive bias circuit 48 into the power amplifier circuit 36, the adaptive bias circuit 48 may also be provided in an external current source 44. In this respect, Figure 6 This is a schematic diagram of an exemplary power amplifier device 57 configured according to another embodiment of the present disclosure. Figure 3 and 6 Common elements between them are shown here with common element designations and will not be described again in this document.

[0051] In this document, power amplifier device 57 includes power amplifier circuitry 58. In an embodiment, power amplifier circuitry 58 includes output stage 38 and bias circuitry 40, while adaptive bias circuitry 48 is disposed in external current source 60. In an embodiment, external current source 60 may include current generator 62 and combiner 64, the current generator generating a low-frequency current I. DC The combiner will convert the low-frequency current I DC With bias current I BIAS Combining to generate a combined low-frequency current I DC+ and combine the low-frequency current I DC+ Injected into bias circuit 40. By separating adaptive bias circuit 48 from power amplifier circuit 58, it is possible to adjust the bias voltage V according to the modulation voltage V. CC Dynamically shaping the low-frequency current I of the combination DC+ This provides more freedom in this regard.

[0052] Figure 3 Power amplifier device 35 and Figure 6The power amplifier device 57 can replace the power amplifier circuit 18 to help improve the overall performance of the existing wireless transmission circuit 10. In this regard, Figure 7 This is a schematic diagram of an exemplary wireless transmitting circuit 66, in which a configuration can be set Figure 3 Power amplifier device 35 and Figure 6 57. Power amplifier device. Figure 3 , 6 The common elements between 7 and 8 are shown with common element designations and will not be described again in this document.

[0053] In this paper, the wireless transmitting circuit 66 reuses the PMIC 12 and transceiver circuit 16 in the existing wireless transmitting circuit 10, replacing the power amplifier circuit 18 only with the power amplifier device 35 or the power amplifier device 57. Therefore, the wireless transmitting circuit 66 can achieve a greater degree of backward compatibility and component reuse.

[0054] Can be provided in communication devices Figure 7 The wireless transmission circuit 66 supports the above embodiments. In this regard, Figure 8 This is a schematic diagram of an exemplary communication device 100, in which a communication device 100 can be provided. Figure 7 The wireless transmission circuit 66.

[0055] In this document, communication device 100 can be any type of communication device, such as a mobile terminal, smartwatch, tablet computer, computer, navigation device, access point, base station (e.g., eNB, gNB, etc.), and any other wireless communication device that supports wireless communication, such as cellular, wireless local area network (WLAN), Bluetooth, ultra-wideband (UWB), and near-field communication. Communication device 100 will typically include a control system 102, a baseband processor 104, a transmitting circuit system 106, a receiving circuit system 108, an antenna switching circuit system 110, multiple antennas 112, and a user interface circuit system 114. In a non-limiting example, as an example, the control system 102 can be a field-programmable gate array (FPGA). In this respect, the control system 102 may include at least a microprocessor, embedded memory circuitry, and a communication bus interface. The receiving circuit system 108 receives radio frequency signals from one or more base stations via antennas 112 and through the antenna switching circuit system 110. Low-noise amplifiers and filters cooperate to amplify and neutralize broadband interference from the received signals for processing. Then, a down-conversion and digitization circuitry system (not shown) down-converts the filtered received signal to an intermediate or baseband frequency signal, which is then digitized into one or more digital streams using an analog-to-digital converter (ADC).

[0056] The baseband processor 104 processes the digitized received signal to extract the information or data bits transmitted in the received signal. This processing typically includes demodulation, decoding, and error correction operations, which will be discussed in more detail below. The baseband processor 104 is typically implemented in one or more digital signal processors (DSPs) and application-specific integrated circuits (ASICs).

[0057] For transmission, baseband processor 104 receives digitized data representing voice, data, or control information from control system 102, and encodes the digitized data for transmission. The encoded data is output to transmission circuitry 106, where a digital-to-analog converter (DAC) converts the digitally encoded data into an analog signal, and a modulator modulates the analog signal onto a carrier signal at one or more desired transmission frequencies. A power amplifier amplifies the modulated carrier signal to a level suitable for transmission and delivers the modulated carrier signal to antenna 112 via antenna switching circuitry 110. Multiple antennas 112 and replicated transmission circuitry 106 and receiver circuitry 108 can provide spatial diversity. Those skilled in the art will understand the modulation and processing details.

[0058] In an embodiment, Figure 3 Power amplifier device 35 and Figure 6 The power amplifier device 57 can be configured to achieve adaptive bias based on the process. In this respect, Figure 9 It is used to implement Figure 3 Power amplifier device 35 and Figure 6 A flowchart of an exemplary process 200 for adaptive biasing in a power amplifier device 57.

[0059] In this paper, process 200 includes generating a low-frequency current I. DC (Step 202). Process 200 also includes based on low-frequency current I. DC Generate bias voltage V DC (Step 204). Process 200 also includes using a bias voltage V. DC The output stage 38 in the bias power amplifier circuit 36 ​​or 58 is based on the modulation voltage V. CC Amplify the RF signal 46 (step 206). Process 200 also includes applying an adaptive bias current I... BIAS Injected into power amplifier circuit 36 ​​or 58 to dynamically adjust the modulation voltage V. CC One or more of the AM / AM characteristics and AM / PM characteristics (step 208).

[0060] Those skilled in the art will recognize improvements and modifications to the embodiments of this disclosure. All such improvements and modifications are considered to be within the scope of the concepts disclosed herein and the following claims.

Claims

1. A power amplifier device (35, 57) comprising: Current source (44, 60), the current source being configured to generate low-frequency current (I DC ); Power amplifier circuits (36, 58), the power amplifier circuits comprising: Bias circuit (40), the bias circuit being configured based on the low-frequency current (I DC Generate bias voltage (V) BIAS );and Output stage (38), the output stage being determined by the bias voltage (V BIAS Bias is based on modulation voltage (V) CC ) Amplify the radio frequency (RF) signal (46); and An adaptive bias circuit (48), coupled to the bias circuit (40), and configured to apply an adaptive bias current (I0) BIAS The voltage is injected into the bias circuit (40) to dynamically adjust one or more of the amplitude-amplitude AM / AM characteristics and amplitude-phase AM / PM characteristics of the modulation voltage.

2. The power amplifier device (35, 57) according to claim 1, wherein the adaptive bias circuit (48) comprises: Bias transistor (50), the bias transistor comprising: The base, which is coupled to the first resistor (R) AB1 And is configured to receive the modulation voltage (V) CC ); Collector, the collector being coupled to the base; and Emitter, the emitter being connected via a second resistor (R) AB2 ) coupled to the bias circuit (40); and Bias capacitor (C) AB The bias capacitor is coupled between the base and ground and is configured to filter out the modulation voltage (V). CC The residual RF component in ).

3. The power amplifier device (35, 57) according to claim 2, wherein the adaptive bias circuit (48) is responsive to the modulation voltage (V CC Automatically activated when the voltage is higher than or equal to the threshold voltage, and in response to the modulation voltage (V). CC It will be deactivated if the voltage is below the threshold voltage.

4. The power amplifier device (35, 57) according to claim 3, wherein the threshold voltage can be adjusted to enable the power amplifier circuit (36, 58) to operate in different gain dispersion regions.

5. The power amplifier device (35, 57) according to claim 2, wherein: The first resistor (R) AB1 The adaptive bias current (I) can be adjusted to control the adaptive bias current. BIAS The slope of ) and The second resistor (R) AB2 The bias circuit (40) can be adjusted to minimize leakage and / or noise injection into the bias circuit (40).

6. The power amplifier device (35, 57) according to claim 2, wherein the bias circuit (40) comprises: A voltage divider network (56) coupled to the current source (44) and configured to operate based on the low-frequency current (I0). DC Output low-frequency voltage; A first transistor (52) having a corresponding collector coupled to the voltage divider network (56); a corresponding base coupled to the corresponding collector; and a second resistor (R) coupled to the adaptive bias circuit (48). AB2 The corresponding emitter of ); as well as The second transistor (54) has a second resistor (R) coupled to the adaptive bias circuit (48). AB2 The corresponding collector of the corresponding emitter of the first transistor (52), the corresponding base coupled to the corresponding collector, and the emitter coupled to the ground.

7. The power amplifier device (35) according to claim 1, wherein the power amplifier circuit (36) further includes the adaptive bias circuit (48), and the current source (44) is external to the power amplifier circuit (36).

8. The power amplifier device (57) according to claim 1, wherein the current source (60) is external to the power amplifier circuit (58) and comprises: Configured to generate the adaptive bias current (I BIAS The adaptive bias circuit (48) of the above. A current generator (62) is configured to generate the low-frequency current (I0). DC ); as well as Combiner (64), which is coupled to the bias circuit (40) and configured to: Combined with the adaptive bias current (I BIAS ) and the low-frequency current (I DC To generate a combined low-frequency current (I) DC+ ); as well as The combined low-frequency current (I) DC+ ) is injected into the bias circuit (40).

9. A wireless device (100) including a wireless transmitting circuit (66), the wireless transmitting circuit comprising: Power management integrated circuit (PMIC) (12), which is configured to generate modulation voltage (V) based on a pre-established lookup table (LUT) (14). CC The lookup table (LUT) compares the time-varying target voltage with the modulation voltage (V). CC Related to; as well as Power amplifier devices (35, 57), the power amplifier devices comprising: Current source (44, 60), the current source being configured to generate low-frequency current (I DC );as well as Power amplifier circuits (36, 58), the power amplifier circuits comprising: Bias circuit (40), the bias circuit being configured based on the low-frequency current (I DC Generate bias voltage (V) BIAS );and Output stage (38), the output stage being determined by the bias voltage (V BIAS Biased based on the modulation voltage (V) CC ) Amplify the radio frequency (RF) signal (46); and An adaptive bias circuit (48), coupled to the bias circuit (40), and configured to apply an adaptive bias current (I0) BIAS ) is injected into the bias circuit (40) to dynamically adjust the modulation voltage (V) CC (Amplitude-amplitude AM / AM characteristics and amplitude-phase AM / PM characteristics) 10. The wireless device (100) of claim 9 further includes a transceiver circuit (16) configured to generate the RF signal (46) and the time-varying target voltage.

11. The wireless device (100) of claim 9, wherein the adaptive bias circuit (48) comprises: Bias transistor (50), the bias transistor comprising: The base, which is coupled to the first resistor (R) AB1 And is configured to receive the modulation voltage (V) CC ); Collector, the collector being coupled to the base; and Emitter, the emitter being connected via a second resistor (R) AB2 ) coupled to the bias circuit (40); and Bias capacitor (C) AB The bias capacitor is coupled between the base and ground and is configured to filter out the modulation voltage (V). CC The residual RF component in ).

12. The wireless device (100) of claim 11, wherein the adaptive bias circuit (48) is responsive to the modulation voltage (V CC Automatically activated when the voltage is higher than or equal to the threshold voltage, and in response to the modulation voltage (V). CC It will be deactivated if the voltage is below the threshold voltage.

13. The wireless device (100) of claim 12, wherein the threshold voltage is adjustable to enable the power amplifier circuit (36, 58) to operate in different gain dispersion regions.

14. The wireless device (100) according to claim 11, wherein: The first resistor (R) AB1 The adaptive bias current (I) can be adjusted to control the adaptive bias current. BIAS The slope of ) and The second resistor (R) AB2 The bias circuit (40) can be adjusted to minimize leakage and / or noise injection into the bias circuit (40).

15. The wireless device (100) of claim 11, wherein the bias circuit (40) comprises: A voltage divider network (56) coupled to the current source (44, 60) and configured to operate based on the low-frequency current (I0). DC Output low-frequency voltage; A first transistor (52) having a corresponding collector coupled to the voltage divider network (56); a corresponding base coupled to the corresponding collector; and a second resistor (R) coupled to the adaptive bias circuit (48). AB2 The corresponding emitter of ); as well as The second transistor (54) has a second resistor (R) coupled to the adaptive bias circuit (48). AB2 The corresponding collector of the corresponding emitter of the first transistor (52), the corresponding base coupled to the corresponding collector, and the emitter coupled to the ground.

16. The wireless device (100) of claim 9, wherein the power amplifier circuit (36, 58) further includes the adaptive bias circuit (48), and the current source (44, 60) is external to the power amplifier circuit (36, 58).

17. The wireless device (100) of claim 9, wherein the current source (44, 60) is external to the power amplifier circuit (36, 58) and comprises: Configured to generate the adaptive bias current (I BIAS The adaptive bias circuit (48) of the above. A current generator (62) is configured to generate the low-frequency current (I0). DC ); as well as Combiner (64), which is coupled to the bias circuit (40) and configured to: Combined with the adaptive bias current (I BIAS ) and the low-frequency current (I DC To generate a combined low-frequency current (I) DC+ ); as well as The combined low-frequency current (I) DC+ ) is injected into the bias circuit (40).

18. A method for implementing adaptive bias in power amplifier circuits (36, 58), comprising: Generating low-frequency current (I DC ); Based on the low-frequency current (I) DC Generate bias voltage (V) BIAS ); Using the aforementioned bias voltage (V) BIAS The output stage of the power amplifier circuit (36, 58) is biased, thereby based on the modulation voltage (V CC ) Amplify the radio frequency (RF) signal (46); and Adaptive bias current (I) BIAS The modulation voltage (V) is injected into the power amplifier circuits (36, 58) to dynamically adjust the modulation voltage (V). CC (Amplitude-amplitude AM / AM characteristics and amplitude-phase AM / PM characteristics) 19. The method of claim 18, further comprising: When the modulation voltage (V CC When the voltage is higher than or equal to the threshold voltage, the adaptive bias current (I) is automatically adjusted. BIAS ) is injected into the power amplifier circuit (36, 58); as well as When the modulation voltage (V CC When the voltage is lower than the threshold voltage, the adaptive bias current (I) will automatically stop. BIAS ) is injected into the power amplifier circuit (36, 58).

20. The method of claim 19, further comprising adjusting the threshold voltage to enable the power amplifier circuit (36, 58) to operate in different gain dispersion regions.

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