Envelope tracking system, envelope tracker and mobile device

Abstract

To provide an envelope tracking system, an envelope tracker, and a mobile device that manage the power of radio frequency (RF) signal transmissions.SOLUTION: An envelope tracking system 100 for generating a power amplifier supply voltage VPA for a power amplifier 71 includes: a multi-level supply (MLS) DC-to-DC converter 72 that outputs a large number of regulated voltages; an MLS modulator 81 that controls selection of the regulated voltages over time on the basis of an analog envelope signal corresponding to the envelope of an RF signal amplified by the power amplifier, and a modulator output filter 91 coupled between an output of the MLS modulator and the power amplifier supply voltage.SELECTED DRAWING: Figure 2

Description

Technical Field

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

Background Art

[0002] In an RF communication system, a power amplifier is used to amplify an RF signal for the purpose of transmission via an antenna. It is important to manage the power of RF signal transmission in order to extend battery life and / or provide an appropriate transmission power level.

[0003] Examples of RF communication systems having one or more power amplifiers include, but are not limited to, mobile phones, tablets, base stations, network access points, customer premise equipment (CPE), laptops, and wearable electronic devices. For example, in a wireless device that communicates using a cellular standard, a wireless local area network (WLAN) standard, and / or any other suitable communication standard, a power amplifier can be used for the purpose of RF signal amplification. The RF signal can have a frequency in the range of about 30 kHz to 300 GHz, such as in the range of about 410 MHz to about 7.125 GHz for fifth generation (5G) cellular communication in frequency range 1 (FR1).

Summary of the Invention

[0004] In certain embodiments, the present disclosure relates to an envelope tracking system. The envelope tracking system is configured to amplify a radio frequency signal and receive power from a power amplifier supply voltage, and is based on an analog envelope signal corresponding to the envelope of the radio frequency signal. and an envelope tracker configured to generate the power amplifier supply voltage. Envelope tracking The device includes a DC / DC converter configured to output a plurality of regulated voltages, and a plurality of regu lated voltages and the analog envelope signal to generate a modulator output voltage at an output section. The device includes a modulator configured to generate the modulator output voltage based on a comparison between the analog envelope signal and a plurality of signal thresholds, and a modulator output filter coupled between the output of the modulator and the power amplifier supply voltage. The modulator is configured to generate the modulator output voltage based on a comparison between the analog envelope signal and a plurality of signal thresholds. In some embodiments, the modulator includes a plurality of switches selectively activated based on a comparison between the analog envelope signal and a plurality of signal thresholds. According to certain embodiments, each of the plurality of switches is connected between the output of the modulator and a corresponding one of the plurality of regulated voltages.

[0005] In some embodiments, the envelope tracker further includes a plurality of modulators including the modulator, and a plurality of modulator output filters including the modulator output filter. Each of the plurality of modulator combinations is coupled to the power amplifier supply voltage via a corresponding one of the plurality of modulator output filters. According to certain embodiments, the number of active ones among the plurality of modulators is selected based on a comparison between the analog envelope signal and a plurality of signal thresholds.

[0006] In various embodiments, the modulator is configured to receive the analog envelope signal via a mobile industry peripheral interface analog reference interface for envelope tracking.

[0007]

[0008] ​​​​​​​​​​​In some embodiments, the analog envelope signal is a differential envelope signal. According to an embodiment, the modulator amplifies a differential envelope signal to generate a single-ended envelope signal. According to various embodiments, the modulator further comprises a differential envelope amplifier configured to generate a differential envelope amplifier. In addition, each of the signals corresponds to a single-ended envelope signal and a corresponding one of a number of signal thresholds. According to some embodiments, the differential envelope is a multiple of a comparator configured to compare the differential envelope. The envelope amplifier includes an amplifier circuit configured to amplify a differential envelope signal and a differential envelope signal. The amplifier circuit operates to compensate for the common mode error caused by the common mode voltage of the and a possible common mode feedback circuit. a first differential input configured to receive a differential envelope signal; and a second differential input configured to receive a differential compensation signal from the buck circuit. According to an embodiment, the common mode feedback circuit is a feedback circuit from the output of the amplifier circuit. In some embodiments, the amplifier circuit is configured to provide a differential input to the second differential input of the amplifier circuit. According to the present invention, the differential envelope amplifier further comprises a filter for filtering the differential envelope signal prior to amplification by the amplifier circuit. The input filter includes a differential input filter configured to filter the differential input.

[0009] In some embodiments, the multiple signal thresholds are each controllable.

[0010] In various embodiments, the envelope tracker further comprises a DC voltage section and a power amplifier supply voltage section. According to certain embodiments, the DC / DC converter includes a DC path filter coupled between the The converter is further configured to generate a DC voltage. The / DC converter is configured to receive the battery voltage and to provide DC / DC conversion of the battery voltage to generate a plurality of regulated voltages and DC voltages based thereon. According to a certain number of embodiments, the DC path filter includes at least one series inductor and at least one shunt capacitor. According to some embodiments, the DC path passing through the DC path filter carries at least 75 percent of the energy provided by the envelope tracker to the power amplifier. In some embodiments, each of the plurality of regulated voltages has a different voltage level. In some embodiments, the envelope tracker further includes a plurality of decoupling capacitors coupled between the ground and a corresponding one of the plurality of regulated voltages. In various embodiments, the modulator output filter includes at least one series inductor and at least one shunt capacitor. According to a certain number of embodiments, the modulator output filter further includes a DC block capacitor connected in series between the modulator output voltage section and the power amplifier supply voltage section. In a given embodiment, the present disclosure relates to an envelope tracker. The envelope tracker includes a power amplifier supply voltage terminal configured to output a power amplifier supply voltage for the power amplifier, a DC / DC converter configured to output a plurality of regulated voltages based on adjusting the battery voltage, a modulator output filter, and a modulator including an output section coupled to the power amplifier supply voltage terminal through the modulator output filter. The modulator includes a plurality of regulated voltages.

[0011]

[0012]

[0013]

[0014] ​ and generating a modulator output voltage at an output based on the analog envelope signal. and adjusting a modulator output voltage based on comparing the analog envelope signal to a plurality of signal thresholds. It is constructed to generate.

[0015] In some embodiments, the modulator comprises a first input to the analog envelope signal and a plurality of signal thresholds. In various embodiments, the method includes the steps of: According to the present invention, each of the multiple switches is connected to a corresponding one of the multiple regulated voltages and the output of the modulator. and a regulated voltage. According to a number of embodiments, the envelope tracker Further, a plurality of modulators including the modulator and a plurality of modulators including the modulator output filter and an output filter, each of the plurality of modulator combinations including the plurality of modulator output filters. In some implementations, the power amplifier supply voltage terminal is coupled to the power amplifier supply voltage terminal via a corresponding one of the filters. According to an embodiment, a plurality of transformations are generated based on a comparison of the analog envelope signal to a plurality of signal thresholds. The number of modulators that are active is selected.

[0016] In various embodiments, the modulator includes a mobile industry peripheral for envelope tracking. Interface - Receive analog envelope signals via analog reference interface It is configured as follows.

[0017] In some embodiments, the analog envelope signal is a differential envelope signal. According to an embodiment, the modulator amplifies the differential envelope signal to convert it into a single-ended envelope signal. In a number of embodiments, the modulator includes a differential envelope amplifier configured to generate a Further, each of the single-ended envelope signals and a corresponding one of a plurality of signal thresholds is including a plurality of comparators configured to compare the same. According to various embodiments, the differential envelope line amplifier includes an amplification circuit configured to amplify a differential envelope line signal, and an operable common mode feedback circuit to cause the amplification circuit to compensate for a common mode error resulting from the common mode voltage of the differential envelope line signal. According to some embodiments, the amplification circuit includes a first differential input part configured to receive a differential envelope line signal, and a second differential input part configured to receive a differential compensation signal from the common mode feedback circuit. According to a certain number of embodiments, the common mode feedback circuit is configured to provide a feedback from the output of the amplification circuit to the second differential input of the amplification circuit. According to various embodiments, the differential envelope line amplifier further includes a differential input filter configured to filter the differential envelope line signal prior to amplification by the amplification circuit. In some embodiments, the plurality of signal thresholds are each controllable. In some embodiments, the envelope tracker further includes a DC path filter coupled between the DC voltage section and the power amplifier supply voltage section. According to a certain number of embodiments, the DC / DC converter is further configured to generate a DC voltage. According to various embodiments, the DC / DC converter is configured to receive a battery voltage and generate a plurality of regulated voltages and a DC voltage based on the DC / DC conversion of the battery voltage. According to some embodiments, the DC path filter includes at least one series inductor and at least one shunt capacitor. According to a certain number of embodiments, the DC path filter is... ...

[0018] In some embodiments, each of the plurality of signal thresholds is controllable.

[0019] In some embodiments, the envelope tracker further includes a DC path filter coupled between the DC voltage section and the power amplifier supply voltage section. According to a certain number of embodiments, the DC / DC converter is further configured to generate a DC voltage. According to various embodiments, the DC / DC converter is configured to receive a battery voltage and generate a plurality of regulated voltages and a DC voltage based on the DC / DC conversion of the battery voltage. According to some embodiments, the DC path filter includes at least one series inductor and at least one shunt capacitor. According to a certain number of embodiments, the DC path filter is... ... ... embodiments, the DC path filter includes at least one series inductor and at least one shunt capacitor. According to a certain number of embodiments, the DC path filter is... The DC path that passes carries at least 5 percent of the energy applied to the power amplifier supply voltage terminal.

[0020] In various embodiments, the plurality of regulated voltages each have a different voltage level.

[0021] In some embodiments, the envelope tracker further includes a plurality of decoupling capacitors coupled between ground and a corresponding one of the plurality of regulated voltages.

[0022] In some embodiments, the modulator output filter includes at least one series inductor and at least one shunt capacitor. According to a certain number of embodiments, the modulator output filter further includes a DC blocking capacitor connected in series between the output of the modulator and the power amplifier supply voltage terminal.

[0023] In a given embodiment, the present disclosure relates to a portable device. The portable device includes a front-end circuit including a transceiver configured to generate a radio frequency transmission signal and a power amplifier configured to receive power from a power amplifier supply voltage to amplify the radio frequency transmission signal, and a power management circuit including an envelope tracker configured to generate a power amplifier supply voltage based on an analog envelope signal corresponding to the envelope of the radio frequency transmission signal. The envelope tracker includes a DC / DC converter configured to output a plurality of regulated voltages, a modulator configured to generate a modulator output voltage at the output based on the plurality of regulated voltages and the analog envelope, and a modulator output filter coupled between the output of the modulator and the power amplifier supply voltage section. The modulator includes an analog envelope signal and a plurality of signal thresholds. ​ configured to generate a modulator output voltage based on a comparison with a threshold value.

[0024] In various embodiments, the modulator includes a plurality of switches that are selectively activated based on a ratio of an analog envelope signal to a plurality of signal threshold values. According to some embodiments, each of the plurality of switches is connected between the output of the modulator and a corresponding one of the plurality of regulated voltages.

[0025] In some embodiments, the envelope tracker further includes a plurality of modulators including the modulator and a plurality of modulator output filters including the modulator output filter, and each of the plurality of modulator couplings is coupled to a power amplifier supply voltage via a corresponding one of the plurality of modulator output filters. According to some embodiments, the number of active ones among the plurality of modulators is selected based on a comparison of the analog envelope signal with a plurality of signal threshold values.

[0026] In various embodiments, the modulator is configured to receive an analog envelope signal via a mobile industry peripheral interface analog reference interface for envelope tracking.

[0027] In some embodiments, the analog envelope signal is a differential envelope signal. According to some embodiments, the modulator includes a differential envelope amplifier configured to amplify the differential envelope signal to generate a single-ended envelope signal. According to various embodiments, the modulator further includes a plurality of comparators each configured to compare the single-ended envelope signal with a corresponding one of the plurality of signal threshold values. According to various embodiments, the differential envelope The amplifier includes an amplification circuit configured to amplify a differential envelope signal, and a common-mode feedback circuit operable to cause the amplification circuit to compensate for a common-mode error resulting from a common-mode voltage of the differential envelope signal. According to a certain number of embodiments, the amplification circuit includes a first differential input part configured to receive the differential envelope signal, and a second differential input part configured to receive a differential compensation signal from the common-mode feedback circuit. According to various embodiments, the common-mode feedback circuit is configured to provide feedback from the output of the amplification circuit to the second differential input of the amplification circuit. According to some embodiments, the differential envelope amplifier further includes a differential input filter configured to filter the differential envelope signal prior to amplification by the amplification circuit. In various embodiments, a plurality of signal thresholds are each controllable. In various embodiments, the envelope tracker further includes a DC path filter coupled between the DC voltage part and the power amplifier supply voltage part. According to a certain number of embodiments, the DC / DC converter is further configured to generate a single DC voltage. According to some embodiments, the portable device further includes a battery that outputs a battery voltage, and the DC / DC converter is configured to generate a plurality of regulated voltages and a single DC voltage based on providing a DC / DC conversion of the battery voltage. According to various embodiments, the DC path filter includes at least one series inductor and at least one shunt capacitor.

[0028] In various embodiments, a plurality of signal thresholds are each controllable.

[0029] In various embodiments, the envelope tracker further includes a DC path filter coupled between the DC voltage part and the power amplifier supply voltage part. According to a certain number of embodiments, the DC / DC converter is further configured to generate a single DC voltage. According to some embodiments, the portable device further includes a battery that outputs a battery voltage, and the DC / DC converter is configured to generate a plurality of regulated voltages and a single DC voltage based on providing a DC / DC conversion of the battery voltage. According to various embodiments, the DC path filter includes at least one series inductor and at least one shunt capacitor. According to a certain number of embodiments, the DC path through the DC path filter is the energy provided from the envelope tracker. In various embodiments, a plurality of signal thresholds are each controllable. In various embodiments, the envelope tracker further includes a DC path filter coupled between the DC voltage part and the power amplifier supply voltage part. According to a certain number of embodiments, the DC path through the DC path filter is the energy provided from the envelope tracker. Carry at least 75 percent of it to the power amplifier.

[0030] In various embodiments, the plurality of regulated voltages each have a different voltage level. have.

[0031] In some embodiments, the envelope tracker further includes a plurality of decoupling capacitors coupled between the ground and a corresponding one of the plurality of regulated voltages. of which.

[0032] In some embodiments, the modulator output filter includes at least one series inductor and at least one shunt capacitor. According to a certain number of embodiments, the modulator output filter further includes a DC block capacitor connected in series between the modulator output voltage section and the power amplifier supply voltage section. and at least one shunt capacitor. According to a certain number of embodiments, the modulator output filter further includes a DC block capacitor connected in series between the modulator output voltage section and the power amplifier supply voltage section. between the modulator output voltage section and the power amplifier supply voltage section. DC block capacitor.

Brief Description of the Drawings

[0033]

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[0034] The following detailed description of a given embodiment presents various descriptions of the particular embodiment. However, the innovation described herein can be embodied in many different ways, for example, as defined by the claims and covered by a number of different aspects. In this specification, drawings that have the same reference numbers indicate elements that are the same or functionally similar. It is understood that the elements shown in the drawings are not necessarily to scale. It is further understood that a given However, the innovation described herein can be embodied in many different ways, for example, as defined by the claims and covered by a number of different aspects. In this specification, drawings that have the same reference numbers indicate elements that are the same or functionally similar. It is understood that the elements shown in the drawings are not necessarily to scale. It is further understood that a given However, the innovation described herein can be embodied in many different ways, for example, as defined by the claims and covered by a number of different aspects. In this specification, drawings that have the same reference numbers indicate elements that are the same or functionally similar. It is understood that the elements shown in the drawings are not necessarily to scale. It is further understood that a given However, the innovation described herein can be embodied in many different ways, for example, as defined by the claims and covered by a number of different aspects. In this specification, drawings that have the same reference numbers indicate elements that are the same or functionally similar. It is understood that the elements shown in the drawings are not necessarily to scale. It is further understood that a given However, the innovation described herein can be embodied in many different ways, for example, as defined by the claims and covered by a number of different aspects. In this specification, drawings that have the same reference numbers indicate elements that are the same or functionally similar. It is understood that the elements shown in the drawings are not necessarily to scale. It is further understood that a given Embodiments may include more elements than shown in the drawings and / or portions of the elements shown in the drawings. Furthermore, some embodiments may also include any suitable combination of features from two or more of the drawings.

[0035] Envelope tracking is a technique that can be used to increase the power added efficiency (PAE) of a power amplifier by efficiently controlling the voltage level of the power amplifier supply voltage in relation to the envelope of the radio frequency (RF) signal amplified by the power amplifier. That is, when the envelope of the RF signal increases, the voltage supplied to the power amplifier can also increase. Similarly, when the envelope of the RF signal decreases, the voltage supplied to the power amplifier also decreases, reducing the power consumption.

[0036] A multilevel envelope tracker with an analog interface is provided herein. In a given embodiment, an envelope tracking system for generating a power amplifier supply voltage for a power amplifier is provided. The envelope tracking system includes a multilevel supply (MLS) DC / DC converter that outputs a number of regulated voltages, an MLS modulator that controls the selection of the regulated voltages over time based on an analog envelope signal corresponding to the envelope of the RF signal amplified by the power amplifier, and a modulator output filter coupled between the output of the MLS modulator and the power amplifier supply voltage section.

[0037] The MLS modulator processes the analog envelope signal to control the modulation operation. For example, in a given implementation, the MLS modulator includes two or more comparators that compare the signal level of the analog envelope signal with different threshold levels. Additionally, the output signals of the comparators are used to control the modulation by controlling the selection of the switches of the modulator. ​

[0038] In a given implementation example, the analog envelope signal is received via a Mobile Industry Processor Interface (MIPI) analog reference interface for envelope tracking (eTrak). Additionally, the MLS modulator processes the analog envelope signal to control the operation of the MLS modulator. That is, the teachings herein can be used to reuse the MIPI eTrak interface for the purpose of multi-level envelope tracking. In a given implementation example, the analog envelope signal is received via a Mobile Industry Processor Interface (MIPI) analog reference interface for envelope tracking (eTrak). Additionally, the MLS modulator processes the analog envelope signal to control the operation of the MLS modulator. That is, the teachings herein can be used to reuse the MIPI eTrak interface for the purpose of multi-level envelope tracking. In a given implementation example, the analog envelope signal is received via a Mobile Industry Processor Interface (MIPI) analog reference interface for envelope tracking (eTrak). Additionally, the MLS modulator processes the analog envelope signal to control the operation of the MLS modulator. That is, the teachings herein can be used to reuse the MIPI eTrak interface for the purpose of multi-level envelope tracking. In a given implementation example, the analog envelope signal is received via a Mobile Industry Processor Interface (MIPI) analog reference interface for envelope tracking (eTrak). Additionally, the MLS modulator processes the analog envelope signal to control the operation of the MLS modulator. That is, the teachings herein can be used to reuse the MIPI eTrak interface for the purpose of multi-level envelope tracking. In a given implementation example, the analog envelope signal is received via a Mobile Industry Processor Interface (MIPI) analog reference interface for envelope tracking (eTrak). Additionally, the MLS modulator processes the analog envelope signal to control the operation of the MLS modulator. That is, the teachings herein can be used to reuse the MIPI eTrak interface for the purpose of multi-level envelope tracking.

[0039] To increase the granularity of modulation control, in a given implementation example, the envelope tracking system includes two or more modulators and two or more corresponding modulator output filters that operate in parallel with each other to generate a power amplifier supply voltage based on the analog envelope signal and the regulated voltage. By including a number of modulators, a fine resolution of quantization can be provided. For example, by activating any number of modulators at a given time, the control over the power amplifier supply voltage can be enhanced compared to an implementation example with a single modulator and a single modulator output filter. To increase the granularity of modulation control, in a given implementation example, the envelope tracking system includes two or more modulators and two or more corresponding modulator output filters that operate in parallel with each other to generate a power amplifier supply voltage based on the analog envelope signal and the regulated voltage. By including a number of modulators, a fine resolution of quantization can be provided. For example, by activating any number of modulators at a given time, the control over the power amplifier supply voltage can be enhanced compared to an implementation example with a single modulator and a single modulator output filter. To increase the granularity of modulation control, in a given implementation example, the envelope tracking system includes two or more modulators and two or more corresponding modulator output filters that operate in parallel with each other to generate a power amplifier supply voltage based on the analog envelope signal and the regulated voltage. By including a number of modulators, a fine resolution of quantization can be provided. For example, by activating any number of modulators at a given time, the control over the power amplifier supply voltage can be enhanced compared to an implementation example with a single modulator and a single modulator output filter. To increase the granularity of modulation control, in a given implementation example, the envelope tracking system includes two or more modulators and two or more corresponding modulator output filters that operate in parallel with each other to generate a power amplifier supply voltage based on the analog envelope signal and the regulated voltage. By including a number of modulators, a fine resolution of quantization can be provided. For example, by activating any number of modulators at a given time, the control over the power amplifier supply voltage can be enhanced compared to an implementation example with a single modulator and a single modulator output filter. To increase the granularity of modulation control, in a given implementation example, the envelope tracking system includes two or more modulators and two or more corresponding modulator output filters that operate in parallel with each other to generate a power amplifier supply voltage based on the analog envelope signal and the regulated voltage. By including a number of modulators, a fine resolution of quantization can be provided. For example, by activating any number of modulators at a given time, the control over the power amplifier supply voltage can be enhanced compared to an implementation example with a single modulator and a single modulator output filter. To increase the granularity of modulation control, in a given implementation example, the envelope tracking system includes two or more modulators and two or more corresponding modulator output filters that operate in parallel with each other to generate a power amplifier supply voltage based on the analog envelope signal and the regulated voltage. By including a number of modulators, a fine resolution of quantization can be provided. For example, by activating any number of modulators at a given time, the control over the power amplifier supply voltage can be enhanced compared to an implementation example with a single modulator and a single modulator output filter. To increase the granularity of modulation control, in a given implementation example, the envelope tracking system includes two or more modulators and two or more corresponding modulator output filters that operate in parallel with each other to generate a power amplifier supply voltage based on the analog envelope signal and the regulated voltage. By including a number of modulators, a fine resolution of quantization can be provided. For example, by activating any number of modulators at a given time, the control over the power amplifier supply voltage can be enhanced compared to an implementation example with a single modulator and a single modulator output filter.

[0040] In a given implementation example, the envelope tracking system further includes a DC path filter coupled between the DC voltage section and the power amplifier supply voltage section. By including the DC path through the DC path filter and the AC path through the modulator output filter, the efficiency of the envelope tracking system can be improved. In a given implementation example, the envelope tracking system further includes a DC path filter coupled between the DC voltage section and the power amplifier supply voltage section. By including the DC path through the DC path filter and the AC path through the modulator output filter, the efficiency of the envelope tracking system can be improved. In a given implementation example, the envelope tracking system further includes a DC path filter coupled between the DC voltage section and the power amplifier supply voltage section. By including the DC path through the DC path filter and the AC path through the modulator output filter, the efficiency of the envelope tracking system can be improved. In a given implementation example, the envelope tracking system further includes a DC path filter coupled between the DC voltage section and the power amplifier supply voltage section. By including the DC path through the DC path filter and the AC path through the modulator output filter, the efficiency of the envelope tracking system can be improved.

[0041] For example, a low-frequency current such as a DC current is provided through the DC path filter (e.g., via an inductive filter), so that the size of the switch of the modulator and / or the DC resistance For example, a low-frequency current such as a DC current is provided through the DC path filter (e.g., via an inductive filter), so that the size of the switch of the modulator and / or the DC resistance The constraints can be relaxed. Therefore, low switching losses in the AC path can be achieved, improving the overall system efficiency. In one example, the DC path carries at least 75% of the energy provided by the envelope tracking system to the power amplifier.

[0042] In a given implementation example, the DC voltage is the regulated voltage from a DC / DC converter. For example, an MLS DC / DC converter can also be used to generate the DC voltage. In such an implementation example, the voltage level of the DC voltage may be the same as or different from one of the regulated voltages

[0043] Figure 1 is a schematic diagram of a mobile device 70 according to an embodiment. The mobile device 70 includes a primary antenna 1, a diversity antenna 2, a primary antenna tuning circuit 3, a diversity antenna tuning circuit 4, a bipolar double-throw (DPDT) antenna diversity switch 5, a primary front-end module 6, a diversity front-end module 7, a battery 8, a multi-level supply (MLS) envelope tracker 9, a transceiver 10, a baseband modem 11, and

[0044] Despite showing one embodiment of a mobile device, the teachings herein are applicable to mobile devices implemented in a wide variety of forms.

[0045] In the illustrated embodiment, the primary front-end module 6 includes a first power amplifier 21, a second power amplifier 22, a third power amplifier 23, , the second low-noise amplifier 32, the third low-noise amplifier 33, the diplexer 42, the transmit / receive band switch 41, the transmit filter 43, the first duplexer 45, the second duplexer 46, the third duplexer 47, the first receive filter 51, the second receive filter 52, the third receive filter 53 , the first directional coupler 59, and the second directional coupler 60. Additionally, the diversity front-end module 7 includes the first low-noise amplifier 35, the second low-noise amplifier 36, the first receive filter 55, the second receive filter 56, the first receive band selection switch 61, and the second receive band selection switch 62.

[0046] Despite showing one embodiment of the front-end circuit, other implementation examples of the front-end circuit are also possible. For example, the front-end circuit may include a power amplifier (PA), a low-noise amplifier (LNA) for processing RF signals transmitted and / or received from one or more antennas, a filter, a switch, a phase shifter, a duplexer, and / or other suitable circuits. Examples of front-end functions include signal amplification for transmission, received signal amplification, signal filtering ing, switching between different bands, switching between different power modes, switching between transmit modes and receive modes, signal duplexing, signal multiplexing (e.g., diplexing, triplexing), or any combination of these, but not limited to these. and receive modes, signal duplexing, signal multiplexing (e.g., diplexing, triplexing), or any combination of these, but not limited to these. (e.g., diplexing, triplexing), or any combination of these, but not limited to these. Therefore, other implementation examples of the primary front-end module, the diversity receive front-end module, antenna selection, and / or antenna tuning may also be used.

[0047]

[0048] ​​As shown in FIG. 1, the MLS envelope tracker 9 generates one or more power amplifier supply voltages for amplifying an RF signal by a power amplifier in the mobile device 70 for wireless transmission purposes. It is used for this purpose. In the illustrated embodiment, the MLS envelope tracker 9 receives a battery voltage V from the battery 8 and generates a first power amplifier supply voltage V for the first power amplifier 21 and a second power amplifier supply voltage V BATT for the second power amplifier 22. Although an example is shown where the MLS envelope tracker 9 generates two power amplifier supply voltages, the MLS PA1 envelope tracker 9 may generate more or fewer power amplifier supply voltages. The MLS envelope tracker 9 controls the first power amplifier supply voltage V PA2 to track the envelope of the first RF signal amplified by the first power amplifier 21. Additionally, the MLS envelope tracker 9 controls the second power amplifier supply voltage V to track the envelope of the second RF signal amplified by the second power amplifier 22. In a given implementation, the MLS envelope tracker 9 receives digital data from the baseband modem 11. For example, the MLS envelope tracker 9 can receive digital data indicating the envelope of the first

[0049] RF signal and the envelope of the second RF signal. The battery 8 may be any suitable battery, such as a lithium-ion battery, for use in the mobile device 70. The battery voltage V PA1 is regulated by a DC / DC converter of the MLS envelope tracker 9 to generate a regulated voltage for use in multi-level envelope tracking according to the teachings herein. RF signal and the envelope of the second RF signal. The supply voltage V PA2 In a given implementation, the MLS envelope tracker 9 receives digital data from the baseband modem 11. For example, the MLS envelope tracker 9 can receive digital data indicating the envelope of the first RF signal and the envelope of the second RF signal. RF signal and the envelope of the second RF signal. It is possible.

[0050] The battery 8 may be any suitable battery, such as a lithium-ion battery, for use in the mobile device 70. The battery voltage V is regulated by a DC / DC converter of the MLS envelope tracker 9 to generate a regulated voltage for use in multi-level envelope tracking according to the teachings herein. BATT is regulated by a DC / DC converter of the MLS envelope tracker 9 to generate a regulated voltage for use in multi-level envelope tracking according to the teachings herein. is regulated by a DC / DC converter of the MLS envelope tracker 9 to generate a regulated voltage for use in multi-level envelope tracking according to the teachings herein. The regulated voltage is generated.

[0051] The transceiver 10 generates an RF signal for transmission and processes the incoming RF signal received from the primary antenna 1 and the diversity antenna 2. As will be understood, the various functions associated with the transmission and reception of RF signals can be achieved by one or more components collectively represented as the transceiver 10 in FIG. 1. In one example, separate components (e.g., separate circuits or dies) may be provided to handle RF signals of a given type.

[0052] The baseband modem 11 provides the transceiver 10 with a digital representation of the transmission signal that the transceiver 10 processes to generate an RF signal for transmission. The baseband modem 11 also processes the digital representation of the received signal provided by the transceiver 10.

[0053] As shown in FIG. 1, the baseband modem 11 is coupled to an application processor 12 that serves to provide primary application processing in the portable device 70. The application processor 12 can provide a variety of functions, such as system capabilities suitable for supporting applications including, but not limited to, memory management, graphics processing, and / or multimedia decoding.

[0054] Although the portable device 70 shows an example of an RF system of a multilevel envelope tracker, one or more multilevel envelope trackers implemented in accordance with the teachings herein can be included in a variety of RF systems.

[0055] FIGS. 2-5 are schematic diagrams of envelope tracking systems for power amplifiers in various embodiments. Draw a figure. However, the teachings herein are applicable to envelope trackers implemented in a variety of ways. Therefore, other implementations are possible.

[0056] Figure 2 is a schematic diagram of an envelope tracking system 100 for a power amplifier 71 according to an embodiment. The envelope tracking system 100 includes, in this embodiment, an MLS DC / DC converter 72, a DC path filter 73, an MLS modulator 81, and a modulator output filter 91 serving as an AC path filter. The MLS DC / DC converter 72 is also referred to as a switching regulator. The power amplifier 71 amplifies an RF input signal RF to generate an RF output signal RF The MLS modulator 81 receives an analog envelope signal (ENVELOPE) that varies in relation to the envelope of the RF input signal RF

[0057] In a given implementation, the analog envelope signal IN corresponds to an envelope signal received from a MIPI eTrak interface. However, OUT other implementations are possible. In the illustrated embodiment, the MLS DC / DC converter 72 receives a battery voltage V IN and provides a DC / DC conversion that generates various regulated voltages V at different voltage levels. Although four MLS voltages are depicted in one example, the MLS DC / DC converter 72 may generate more or fewer MLS voltages, as indicated by the ellipsis. In this embodiment, the MLS DC / DC In this embodiment, the MLS DC / DC converter 72 receives a battery voltage V

[0058] and provides a DC / DC conversion that generates various regulated voltages V BATT and generates various regulated voltages V at different voltage levels. MLSa V MLSb V MLSc ... V MLSn Although four MLS voltages are depicted in one example, the MLS DC / DC converter 72 may generate more or fewer MLS voltages, as indicated by the ellipsis. In this embodiment, the MLS DC / DC In this embodiment, the MLS DC / DC converter 72 receives a battery voltage V and provides a DC / DC conversion that generates various regulated voltages V The C converter 72 also generates a DC voltage V BATT by adjusting the battery voltage V DC . The DC voltage V may be the same as or different from one of the voltage levels of the regulated voltages V DC , V MLSa , V MLSb , V MLSc …V MLS n .

[0059] The MLS modulator 81 receives the regulated voltages V MLSa , V MLSb , V MLSc …V MLSn and an analog envelope signal, and outputs a modulator output voltage to the modulator output filter 91 . In a given implementation, the MLS modulator 81 controls the output voltage based on selecting an appropriate regulated voltage over time based on the analog envelope signal. For example, the MLS modulator 81 may include a bank of switches that selectively connect one of the regulated voltages V , V MLSa , V MLSb , V MLSc …V MLSn to the output of the modulator.

[0060] In a given implementation, the MLS modulator 81 generates a modulator output voltage based on comparing the analog envelope signal to two or more signal thresholds. For example, the MLS modulator 81 may include two or more comparators that compare the analog envelope signal to different signal thresholds. Additionally, the MLS modulator 81 may include a plurality of switches. Each switch is connected between the output of the MLS modulator 81 and a corresponding one of the plurality of regulated voltage sections. These switches may be individually activated based on the comparison.

[0061] The DC path filter 73 and the modulator output filter 91 each filter the DC voltage V from the MLS DC / DC converter 72 and the output of the MLS modulator 81 to generate the power amplifier supply voltage V for the power amplifier 71. DC By including a DC path through the DC path filter 73 and an AC path through the modulator output filter 91, an improvement in the efficiency of the envelope tracking system 100 can be achieved. For example, since low-frequency currents (including but not limited to DC currents) are provided through the DC path filter 73, the constraints on the size and / or DC resistance of the switches of the MLS modulator can be relaxed. PA Thus, low switching losses in the AC path can be achieved, improving the overall system efficiency. In one example, the DC path carries at least 75% of the energy that the envelope tracking system 100 supplies to the power amplifier 71.

[0062]

[0063]

[0064]

[0065] FIG. 3C is a schematic diagram of an envelope tracking system 140 for a power amplifier 101 in another embodiment. The envelope tracking system 140 includes an envelope tracking integrated circuit (IC) 102, a DC path filter 103, a modulator output filter 104 (which serves as an AC path filter in this embodiment), a DAC circuit 105, an envelope filter 106, first decoupling capacitors 111 to fourth decoupling capacitors 114, and an inductor 117.

[0065] Although an embodiment envelope tracking system is shown in FIG. , are applicable to envelope tracking systems implemented in a wide variety of ways. An implementation example is also possible.

[0066] In the illustrated embodiment, the envelope tracking IC 102 includes an MLS switching circuit 121 and , a digital control circuit 122, a baseband MLS modulator 123, and a modulator control circuit 124. The envelope tracking IC 102 of FIG. 3A includes, for example, a battery voltage (V BATT ) reception, Communication via Real Peripheral Interface (SPI), DC voltage V DC The output of Receive differential analog envelope signals (ENV_p, ENV_n), decoupling capacitors 111-114 and the inductor 117. The envelope tracking IC is depicted here with various pins or pads for Also called a semiconductor die or chip.

[0067] MLS switching circuit 121 controls the current through inductor 117 to provide voltage regulation. For example, the MLS switching circuit 121 includes a switch and a controller. The controller may be any suitable modulation scheme (including but not limited to pulse width modulation). This switch is turned on and off using a scheme to provide DC / DC conversion. In an embodiment, the MLS switching circuit 121 has four adjustable inputs at different voltage levels. The adjusted MLS voltage and the adjusted DC voltage V DC However, the MLS switch The switching circuit 121 may be implemented to output a regulated voltage that is greater or less than this. This is also fine.

[0068] As shown in FIG. 3A, the MLS switching circuit 121 is controlled by a digital control circuit 122. The digital control circuit 122 provides programming capabilities to the MLS switching circuit 121, including but not limited to voltage level control of one or more regulated voltages output by the MLS switching circuit 121. As shown in FIG. 3A, the digital control circuit 122 is coupled to the SPI bus. In a given implementation example, the digital control circuit 122 controls the MLS switching circuit 121 based on data received via the SPI bus and / or other chip interfaces.

[0069] The baseband MLS modulator 123 includes an output section coupled to the power amplifier supply voltage V via the modulator output filter 104. In a given implementation example, the baseband MLS modulator 123 includes switches coupled between each regulated MLS voltage and the modulator output filter 104. Additionally, the modulator switches are selectively opened or closed by a modulator controller 124 based on an analog envelope signal. PA

[0070] In a given implementation example, the modulator control circuit 124 includes a differential envelope amplifier that converts a differential analog envelope signal to a single - end envelope signal, and two or more comparators that compare the single - end analog envelope signal to different signal thresholds. Additionally, the modulator controller 124 controls the activation of the switches of the MLS modulator 123 based on the result of the comparison.

[0071] In the illustrated embodiment, the DC path filter 103 includes a shunt capacitor 127 and ​​​​​​​​​​​​​​It includes a series inductor 128. Additionally, the modulator output filter 104 includes a first series inductor 131, a second series inductor 132, a first shunt capacitor 135, and a second shunt capacitor 136. Although an implementation example of the DC path filter and the modulator output filter 104 is depicted in FIG. 3A, the teachings herein are applicable to filters implemented in a wide variety of manners. Thus, filters of other implementation examples can also be used in accordance with the teachings herein. In a given implementation example, one or more components of the filter are controllable to improve flexibility and / or controllability (e.g., digitally programmable and / or analog tuned). For example, in the illustrated embodiment, the first shunt capacitor 135 and the second shunt capacitor 136 are controllable. Although two examples of controllable filter components are shown, additional or alternative implementations may be made to render other filter components controllable. FIG. 3B is a schematic diagram of an envelope tracking system 150 for a power amplifier 101 in another embodiment. The envelope tracking system 150 of FIG. 3B is similar to the envelope tracking system 140 of FIG. 3A, except that the envelope tracking system 150 includes a different implementation example of the modulator output filter 144. For example, compared to the modulator output filter 104 of FIG. 3A, the modulator output filter 144 of FIG. 3B further includes a DC blocking capacitor 138 that blocks low-frequency current passing through the modulator output filter 144. In the illustrated embodiment, the DC blocking capacitor 138 is included.

[0072]

[0073]

[0074] ​​​​​​​​​​​​​​ 8 is coupled to the output of the modulator output filter 144.

[0075] By including the DC block capacitor 138, low switching loss in the AC path can be achieved, thus improving the overall system efficiency. For example, the DC block capacitor 138 is useful for increasing the percentage of energy carried by the DC path through the DC path filter 103 relative to the energy carried by the AC path through the modulator output filter 144. In one example, the DC path carries at least 75% of the energy provided by the envelope tracking system 150 to the power amplifier 101. to the power amplifier 101.

[0076] FIG. 3C is a schematic diagram of an envelope tracking system 160 for a power amplifier in another embodiment. The envelope tracking system 160 of FIG. 3C is similar to the envelope tracking system 150 of FIG. 3B, except that the envelope tracking system 160 includes a different implementation example of the modulator output filter 154.

[0077] For example, compared to the modulator output filter 144 of FIG. 3B, the modulator output filter 154 of FIG. 3C includes a DC block capacitor 138 coupled to the input of the filter. The DC block capacitor may be included at various locations in the modulator output filter, such as at the input, at the output, or along the signal path between the input and the output.

[0078] FIG. 4 is a schematic diagram of an envelope tracking system 170 for a power amplifier in another embodiment. The envelope tracking system 170 includes an MLS DC / DC converter 72, a DC path filter ​​​​​​​​​​73. The MLS modulators 81a, 81b, … 81n, and the modulator output filters 91a, 91b, … 91n are included.

[0079] The envelope tracking system 170 of FIG. 4 is similar to the envelope tracking system 100 of FIG. 2, but the envelope tracking system 170 includes a plurality of modulators and a plurality of modulator output filters that operate in parallel with each other to generate a power amplifier supply voltage based on an analog envelope signal and an adjusted voltage. This is different in that it includes filters.

[0080] By including a large number of modulators, a fine resolution of quantization can be provided. For example, any number (0, 1, 2, etc.) of the modulators can be activated at a given time to enhance the control of the power amplifier supply voltage.

[0081] FIG. 5 is a schematic diagram of an envelope tracking system 180 for a power amplifier according to another embodiment. The envelope tracking system 180 of FIG. 5 includes an envelope tracking IC 172, a DC path filter 103, a first modulator output filter 144a, a second modulator output filter 144b, a D AC circuit 105, an envelope filter 106, first decoupling capacitors 111 to fourth decoupling capacitors 114 respectively, and an inductor 117. The envelope tracking IC 172 includes an MLS switching circuit 121, a digital control circuit 122, a first base band MLS modulator 123a, a second base band MLS modulator 123b, and a modulator control circuit 124. Although an example with two base band MLS modulators is shown, more or fewer base band MLS modulators may be included.

[0082] The modulator control circuit 124 is based on the differential analog envelope signals ENV_p and ENV_n to control the MLS modulators 123a and 123b. The modulator control circuit 124 controls specific modulator switches that open or close in each modulator, and can control whether one or both of the MLS modulators 123a and 123b are activated. By including two or more MLS modulators, quantization can be improved and control over the generation of the power amplifier supply voltage V can be enhanced. In a predetermined implementation example, the modulator control circuit 124 includes a differential envelope amplifier that converts the differential analog envelope signal into a single PA end envelope signal, and two or more comparators that compare the single-ended analog envelope signal with different signal thresholds. Additionally, the modulator controller 124 controls the activation of the switches of the MLS modulators 123a and 123b based on the result of the comparison.

[0083] FIG. 6A is a schematic diagram of a differential envelope amplifier 210 of an embodiment for an envelope tracking system. The differential envelope amplifier 210 includes an amplification circuit 201, a common mode feedback circuit 202, and a differential input filter 203. The differential envelope amplifier 210 of FIG. 6A shows a differential envelope amplifier of an embodiment. In a predetermined implementation example, the differential envelope amplifier is included in an envelope tracking interface that converts the differential envelope signal into a single-ended envelope signal and / or compensates for common mode errors. For example, the differential envelope tracker may be included in the control circuit of the modulator. An example of a differential envelope amplifier is shown

[0084]

[0085] ​​​​​​​​​Nevertheless, the differential envelope amplifier can be implemented in a variety of ways.

[0086] The differential input filter 203 receives the differential analog envelope signals ENV_p and ENV_n and filters the differential analog envelope signals to generate filtered differential analog envelope signals.

[0087] The amplifier circuit 201 includes a first differential input section that receives the filtered differential analog envelope signal from the differential input filter 203, and a second differential input section that receives the differential compensation signal from the common mode feedback circuit 202. The amplifier circuit 201 includes an output section that generates a single-ended analog envelope signal ENV.

[0088] As shown in FIG. 6A, the common mode feedback circuit 202 is connected between the output section of the amplifier circuit 201 and the second differential input section of the amplifier circuit 201. The common mode feedback circuit 202 provides, in this example, a conversion from a single-ended signal to a differential signal.

[0089] The common mode feedback circuit 202 provides feedback to compensate for errors resulting from the common mode voltages of the differential analog envelope signals ENV_p and ENV_n for the amplifier circuit 201.

[0090] FIG. 6B is a schematic diagram of a differential envelope amplifier 240 for one embodiment of an envelope tracking system. The differential envelope amplifier 240 includes an amplifier circuit 211, a common mode feedback circuit 212, and a differential input filter 213.

[0091] ​​​The differential envelope amplifier 240 in FIG. 6B is similar to the differential envelope amplifier 210 in FIG. 6A, but is different in that the differential envelope amplifier 240 includes a circuit of a specific implementation example. Although an example of the circuit is shown the differential envelope amplifier can be implemented in other ways.

[0092] In the illustrated embodiment, the amplifier circuit 211 includes a first differential input section, a second differential input section, and an output section. The first differential input is a voltage input associated with a first mutual conductance Gm_IN, and the second differential input is a voltage input associated with a second mutual conductance Gm_FBK. In a predetermined implementation example, the amount of the mutual conductance of Gm_IN is larger than the amount of the mutual conductance of Gm _FBK. Continuing to refer to FIG. 6B, the common mode feedback circuit 212 includes a first resistor 221 and a second resistor 222, which operate as a voltage divider

[0093] to generate a divided voltage V . The first resistor 221 and the second resistor 222 are connected in series between the output of the amplifier circuit 211 and a reference voltage such as ground. The common mode feedback circuit DIV 212 includes a capacitor 224 parallel to the first resistor 221. The common mode feedback circuit 212 further includes a third resistor 223 and a current source 225 connected in series between the supply voltage and ground. The second differential input section of the amplifier circuit 221 compares the voltage V across the third resistor 223 generated by the first resistor 221 and the second resistor 222 with the divided voltage V . In a predetermined implementation example, the current source 225 is controllable (e.g., variable and / or programmable) to control the common mode setting of the common mode feedback circuit 212. R V DIV and the common mode feedback circuit 212. back circuit 212. is gramable).

[0094] The common-mode feedback circuit 212 operates to provide feedback for controlling the output DC bias point or level of the amplifier circuit 211, so that the influence of the common-mode voltage of the differential analog envelope line signals ENV_P and ENV_n is reduced or eliminated.

[0095] In the illustrated embodiment, the differential input filter 213 includes a first filter resistor 231, a second filter resistor 232, and a filter capacitor 233. The differential input filter 2 13 provides low-pass filtering of the differential analog envelope signals ENV_p and ENV_n and supplies the filtered differential analog envelope signal to the first differential input section of the amplifier circuit 211.

[0096] FIG. 7 is a schematic diagram of an amplifier circuit 400 according to an embodiment of the differential envelope amplifier of FIGS. 6A and 6B. Although an example of a suitable amplifier circuit is shown, the differential envelope amplifier may include amplifier circuits implemented in a wide variety of manners.

[0097] As shown in FIG. 7, the differential amplifier circuit 400 includes a first pair of p-type field effect transistors (PFETs) 301 to 302 that amplify the first differential input IN p , IN n . The first pair of PFETs 301 to 302 are biased by a first pair of current sources 321 to 322 (each providing a current I in this example) and include a first resistor 331 having a resistance value R that couples the source of PFET 301 to the source of PFET 30 2. The differential amplifier circuit 400 further includes B IAS and a first resistor 331 having a resistance value R that couples the source of PFET 301 to the source of PFET 302. The differential amplifier circuit 400 further includes ​​​​, a second differential input V corresponding to the differential common mode compensation signal INp_fd , V INn_fd is amplified and includes a second pair of PFETs 303 - 304. The second pair of PFETs 303 - 304 are biased by a second pair of current sources 323 - 324 (also providing current I BIAS in this example) and include a second resistor 332 (also having a resistance value R in this example) that couples the source of PFET 303 to the source of PFET 304.

[0098] The current from the first pair of PFETs 301 - 302 and the current from the second pair of PFETs 303 - 304 are combined using a folded cascode circuit. This folded cascode circuit includes current sources 325 - 326, cascode n - type field - effect transistors (NFETs) 311 - 312, and load PFETs 313 - 314. In this example, the gates of the cascode NFETs 311 - 312 are controlled by a bias voltage V BIAS .

[0099] The amplifier circuit 400 further includes a push - pull output stage. This push - pull output stage includes an output NFET 317, an output PFET 318, a current source 327, and a class - AB bias circuit 328. As shown in FIG. 7, the current source 327 supplies current I BIAS_AB to the class - AB bias circuit 328. The class - AB bias circuit 328 biases the output NFET 317 and the output PFET 318 to improve the bandwidth.

[0100] FIG. 8 is a graph of an example of a differential analog envelope signal voltage versus time. As shown in FIG. 8, the non - inverted envelope signal ENV_p and the inverted envelope signal ENV_n are differential analog envelopes ​​​​operates as. By using differential signals, common-mode noise (V_cm) can be blocked off.

[0101] In one example, the differential analog envelope signal is a 1.2V differential envelope signal with a 1.5V peak-to-peak maximum input amplitude or a 1.8V differential envelope signal with a 2V peak-to-peak maximum input amplitude, corresponding to the MIP eTrak envelope signal.

[0102] FIG. 9 is a schematic diagram of a comparator circuit 610 for an embodiment of an MLS modulator. The comparator circuit 610 includes comparators 601a, 601b,... 601m, resistors 603a, 603 b,... 603m, and controllable current sources 602a, 602b,... 602m.

[0103] Although an example with three comparators and corresponding circuits is shown, more or fewer comparators may be included, as indicated by the ellipsis. Further, although an implementation example of a comparator circuit for an MLS modulator is shown, other implementation examples of the comparator circuit according to the teachings herein may be used.

[0104] The comparator circuit 610 receives a single-ended analog envelope signal ENV (e.g., from a differential envelope amplifier 210 in FIG. 6A or a differential envelope amplifier 240 in FIG. 6B, but not limited to these differential envelope amplifiers) and generates comparator output signals Lvla, Lvlb,... Lvlm.

[0105] The comparator output signals Lvla, Lvlb,... Lvlm are generated based on the comparison of the single-ended envelope signal ENV with different signal thresholds. For example, comparators 601a, 601 b, … 601m each receive a common reference voltage Vref, yet the controllable current sources 602a, 602b, … 602m respectively control separate thresholds for comparators 601a, 601b, … 601 m. For example, the voltage drops across resistors 603a, 603b, … 603m respectively and the corresponding signal thresholds used for comparison are controlled by the amplitudes of the currents from controllable current sources 602a, 602b, … 602m.

[0106] In the illustrated embodiment, n-bit digital control signals LKa<1:n>, LKb<1 :n>, …, LKm<1:n> are used to control the levels of the signal thresholds of each of comparators 601a, 601b, … 601m. In a given implementation example, the digital control signals are controlled based on data received via an interface such as, for example, an SPI bus. Despite showing an example of signal threshold control, the teachings herein are applicable to signal threshold control implemented in other manners.

[0107] In a given implementation example, comparator output signals Lvla, Lvlb, … Lvlm are used to control the selection of individual switches of a modulator and / or the selectable activation of a fixed number of active modulators in a multi-modulator implementation example.

[0108] Figure 10 is a schematic diagram of an embodiment of comparator 720 of comparator circuit 610 of Figure 9. Despite showing an example of a suitable comparator, an MLS modulator may include comparators implemented in a wide variety of manners.

[0109] Comparator 720 includes a pair of input NFETs 701a~701b, a pair of bias NFETs 7 02a to 702b, the first pair of load PFETs 703a to 703b, the second pair of load PFETs 7 04a to 704b, the first pair of current source PFETs 705a to 705b, the first pair of mirror NFEs Ts 706a to 706b, the second pair of current source PFETs 707a to 707b, the second pair of mirror N FETs 708a to 708b, a pair of current source NFETs 710a to 710b, the third pair of load P FETs 709a to 709b, a pair of output PFETs 711a to 711b, and a pair of output N FETs 712a to 712b. In a predetermined implementation example, the bias NFET 702b is , and is scaled in size compared to the bias NFET 702a (for example, has a large de vice width), but is implemented with a matched transistor layout.

[0110] In the illustrated embodiment, the comparator 720 receives an input voltage Vin and a reference voltage Vref , and outputs differential comparison signals OUT+, OUT- indicating the comparison result. The comparator 720 is biased by a current I BIAS , and receives a received a power supply voltage VDD and a ground voltage GND. In this example, although the comparison signals are implemented differentially, either of the signal components of the differential comparison signals OUT+ , OUT- may be used as a single-ended comparison signal.

[0111] FIG. 11 is a schematic diagram of a portable device 800 according to another embodiment. The portable device 8 00 includes a baseband system 801, a transceiver 802, a front-end system 803, an antenna 804, a power management system 805, a memory 806, a user interface 807 , and a battery 808.

[0112] The portable device 800 supports 2G, 3G, 4G (LTE, LTE Advanced, and LTE Advanced Pro), 5G, WLAN (e.g., Wi-Fi), WPAN (e.g., Blue tooth (trademark) and ZigBee (trademark)), WMAN (e.g., WiMax ), and / or GPS technology, and can be used to communicate using a variety of communication technologies including but not limited to these. It can be used to communicate.

[0113] The transceiver 802 generates RF signals for transmission and processes the incoming RF signals received from the antenna 804. As will be understood, the various functions associated with the transmission and reception of RF signals can be achieved by one or more components collectively represented as the transceiver 802 in FIG. 11. In one example, separate components (e.g., separate circuits or dies) may be provided to handle a given type of RF signal. It is understood that the various functions associated with the transmission and reception of RF signals can be achieved by one or more components collectively represented as the transceiver 802 in FIG. 11. In one example, separate components (e.g., separate circuits or dies) may be provided to handle a given type of RF signal. For example, separate components (e.g., separate circuits or dies) may be provided to handle a given type of RF signal.

[0114] The front-end system 803 assists in conditioning the signals transmitted to and / or received from the antenna 804. In the illustrated embodiment, the front-end system 803 includes a power amplifier (PA) 811, a low-noise amplifier (LNA) 812, a filter 813, a switch 814, and a duplexer 815. However, other implementations are also possible. For example, the front-end system 803 may include amplification of the transmitted signal, amplification of the received signal, filtering of the signal, switching between different bands, switching between different power modes, switching between the transmit mode and the receive mode, duplexing of the signal, multiplexing of the signal (e.g., diplexing or triplexing), or any combination of these.

[0115] For example, the front-end system 803 may include amplification of the transmitted signal, amplification of the received signal, filtering of the signal, switching between different bands, switching between different power modes, switching between the transmit mode and the receive mode, duplexing of the signal, multiplexing of the signal (e.g., diplexing or triplexing), or any combination of these. mode and the receive mode, duplexing of the signal, multiplexing of the signal (e.g., diplexing or triplexing), or any combination of these. xing (e.g., diplexing or triplexing), or any combination of these. It is possible to provide a certain number of functions including but not limited to matching.

[0116] In a specific implementation example, the mobile device 800 supports carrier aggregation so as to obtain the flexibility to increase the peak data rate. Carrier aggregation can be used for both frequency division duplexing (FDD) and time division duplexing (TDD) so that it can be used to aggregate (aggregate) multiple carriers or channels. Carrier aggregation includes continuous aggregation in which continuous carriers within the same operating frequency band are aggregated. Carrier aggregation may be discontinuous and may include carriers with separated frequencies within a common band or different bands.

[0117] The plurality of antennas 804 can include antennas used for a variety of types of communication For example, the antenna 804 can include antennas associated with the transmission and / or reception of signals associated with a variety of frequencies and communication standards.

[0118] In a specific implementation example, the antenna 804 supports MIMO communication and / or switched diversity city communication. For example, MIMO communication uses multiple antennas that communicate multiple data streams through a single radio frequency channel. MIMO communication benefits from high signal-to-noise ratio, improved coding, and / or signal interference reduction due to spatial multiplexing (multiplexing) of the wireless environment. Switched diversity refers to communication in which a specific antenna operating at a specific time is selected. For example, a specific one is selected from a group of antennas based on various factors such as observed bit error rate and / or signal strength indicator. A switch can be used to select the antenna of .

[0119] In a given implementation example, the mobile device 800 can operate with beamforming. For example, the front-end system 803 can include a phase shifter with variable phase controlled by the transceiver 802. Additionally, the phase shifter is controlled to provide beam formation and directivity for signal transmission and / or reception using the antenna 804. For example, in the context of signal transmission, the phase of the transmission signal applied to the antenna 804 is controlled such that the signals radiated from the antenna 804 are combined using constructive and destructive interference, resulting in an aggregated transmission signal with a quality such as a strong signal intensity propagating in a given direction. In the context of signal reception, the phase is controlled such that a large amount of signal energy is received when the signal reaches the antenna 804 from a specific direction. In a given implementation example, the antenna 804 includes one or more arrays of antenna elements to enhance beamforming.

[0120]

[0121] The baseband system 801 is coupled to a user interface 807 that facilitates the processing of various user inputs / outputs (I / Os) such as voice and data. The baseband system 801 provides the digital representation of the transmission signal to the transceiver 802, which processes it to generate an RF signal for transmission. The baseband system 801 also processes the digital representation of the received signal provided by the transceiver 802. As shown in FIG. 11, the baseband system 801 is coupled to the memory 806 to facilitate the operation of the mobile device 800.

[0120]

[0121] ​​​​​ Memory 806 is used for a variety of purposes, such as storing data and / or instructions, to facilitate the operation of portable device 800 and / or to provide storage of user information. It can be used for a variety of purposes, such as storing data and / or instructions, to facilitate the operation of portable device 800 and / or to provide storage of user information. It can be used.

[0122] Power management system 805 provides a certain number of power management functions for portable device 800. The power management system 805 may include an MLS envelope tracker 860 implemented in accordance with one or more features of the present disclosure. Power management system 805 may include an MLS envelope tracker 860 implemented in accordance with one or more features of the present disclosure. It may include.

[0123] As shown in FIG. 11, power management system 805 receives a battery voltage from battery 808. Battery 808 may be any suitable battery, such as a lithium-ion battery, for use in portable device 800. As shown in FIG. 11, power management system 805 receives a battery voltage from battery 808. Battery 808 may be any suitable battery, such as a lithium-ion battery, for use in portable device 800. It may be any suitable battery, such as a lithium-ion battery, for use in portable device 800.

[0124] FIG. 12 is a schematic diagram of an embodiment of a communication system 950 that transmits RF signals. Communication system 950 includes a battery 901, an MLS envelope tracker 902, a power amplifier 903, a directional coupler 904, a duplexing switching circuit 905, an antenna 906, a baseband processor 907, a signal delay circuit 908, a digital pre-distortion (DPD) circuit 909, an I / Q modulator 910, an observation receiver 911, an intermodulation detection circuit 912, an envelope delay circuit 921, a coordinate rotation digital calculation (CORDIC) circuit 922, a shaping circuit 923, a digital / analog converter 924, and a reconstruction filter 925. Communication system 950 includes a battery 901, an MLS envelope tracker 902, a power amplifier 903, a directional coupler 904, a duplexing switching circuit 905, an antenna 906, a baseband processor 907, a signal delay circuit 908, a digital pre-distortion (DPD) circuit 909, an I / Q modulator 910, an observation receiver 911, an intermodulation detection circuit 912, an envelope delay circuit 921, a coordinate rotation digital calculation (CORDIC) circuit 922, a shaping circuit 923, a digital / analog converter 924, and a reconstruction filter 925. Communication system 950 includes a battery 901, an MLS envelope tracker 902, a power amplifier 903, a directional coupler 904, a duplexing switching circuit 905, an antenna 906, a baseband processor 907, a signal delay circuit 908, a digital pre-distortion (DPD) circuit 909, an I / Q modulator 910, an observation receiver 911, an intermodulation detection circuit 912, an envelope delay circuit 921, a coordinate rotation digital calculation (CORDIC) circuit 922, a shaping circuit 923, a digital / analog converter 924, and a reconstruction filter 925. Communication system 950 includes a battery 901, an MLS envelope tracker 902, a power amplifier 903, a directional coupler 904, a duplexing switching circuit 905, an antenna 906, a baseband processor 907, a signal delay circuit 908, a digital pre-distortion (DPD) circuit 909, an I / Q modulator 910, an observation receiver 911, an intermodulation detection circuit 912, an envelope delay circuit 921, a coordinate rotation digital calculation (CORDIC) circuit 922, a shaping circuit 923, a digital / analog converter 924, and a reconstruction filter 925. Communication system 950 includes a battery 901, an MLS envelope tracker 902, a power amplifier 903, a directional coupler 904, a duplexing switching circuit 905, an antenna 906, a baseband processor 907, a signal delay circuit 908, a digital pre-distortion (DPD) circuit 909, an I / Q modulator 910, an observation receiver 911, an intermodulation detection circuit 912, an envelope delay circuit 921, a coordinate rotation digital calculation (CORDIC) circuit 922, a shaping circuit 923, a digital / analog converter 924, and a reconstruction filter 925. Communication system 950 includes a battery 901, an MLS envelope tracker 902, a power amplifier 903, a directional coupler 904, a duplexing switching circuit 905, an antenna 906, a baseband processor 907, a signal delay circuit 908, a digital pre-distortion (DPD) circuit 909, an I / Q modulator 910, an observation receiver 911, an intermodulation detection circuit 912, an envelope delay circuit 921, a coordinate rotation digital calculation (CORDIC) circuit 922, a shaping circuit 923, a digital / analog converter 924, and a reconstruction filter 925.

[0125] Communication system 950 of FIG. 12 shows an example of an RF system that may include an envelope tracking system implemented in accordance with one or more features of the present disclosure. However, the teachings herein are applicable to RF systems implemented in a variety of manners. Communication system 950 of FIG. 12 shows an example of an RF system that may include an envelope tracking system implemented in accordance with one or more features of the present disclosure. However, the teachings herein are applicable to RF systems implemented in a variety of manners. However, the teachings herein are applicable to RF systems implemented in a variety of manners.

[0126] The baseband processor 907 operates to generate an in-phase (I) signal and a quadrature-phase (Q) signal corresponding to the signal components of a sine wave or a sine signal of a desired amplitude, frequency, and phase. For example, the I signal and the Q signal provide an equivalent representation of a sine wave. In a given implementation, the I signal and the Q signal are output in digital form. The baseband processor 907 may be any suitable processor for processing baseband signals. For example, the baseband processor 907 may include a digital signal processor, a microprocessor, a programmable core, or any combination thereof. For example, the I signal and the Q signal provide an equivalent representation of a sine wave. In a given implementation, the I signal and the Q signal are output in digital form. The baseband processor 907 may be any suitable processor for processing baseband signals. For example, the baseband processor 907 may include a digital signal processor, a microprocessor, a programmable core, or any combination thereof. For example, the I signal and the Q signal provide an equivalent representation of a sine wave. In a given implementation, the I signal and the Q signal are output in digital form. The baseband processor 907 may be any suitable processor for processing baseband signals. For example, the baseband processor 907 may include a digital signal processor, a microprocessor, a programmable core, or any combination thereof. For example, the I signal and the Q signal provide an equivalent representation of a sine wave. In a given implementation, the I signal and the Q signal are output in digital form. The baseband processor 907 may be any suitable processor for processing baseband signals. For example, the baseband processor 907 may include a digital signal processor, a microprocessor, a programmable core, or any combination thereof. For example, the I signal and the Q signal provide an equivalent representation of a sine wave. In a given implementation, the I signal and the Q signal are output in digital form. The baseband processor 907 may be any suitable processor for processing baseband signals. For example, the baseband processor 907 may include a digital signal processor, a microprocessor, a programmable core, or any combination thereof. For example, the I signal and the Q signal provide an equivalent representation of a sine wave. In a given implementation, the I signal and the Q signal are output in digital form. The baseband processor 907 may be any suitable processor for processing baseband signals. For example, the baseband processor 907 may include a digital signal processor, a microprocessor, a programmable core, or any combination thereof.

[0127] The signal delay circuit 908 provides an adjustable delay to the I signal and the Q signal, and assists in controlling the relative alignment between the differential analog envelope signals ENV_p and ENV_n provided to the envelope tracker 902 and the RF signal RF provided to the power amplifier 903. The amount of delay provided by the signal delay circuit 908 is controlled based on the amount of intermodulation in the adjacent band detected by the intermodulation detection circuit 912. The signal delay circuit 908 provides an adjustable delay to the I signal and the Q signal, and assists in controlling the relative alignment between the differential analog envelope signals ENV_p and ENV_n provided to the envelope tracker 902 and the RF signal RF provided to the power amplifier 903. The amount of delay provided by the signal delay circuit 908 is controlled based on the amount of intermodulation in the adjacent band detected by the intermodulation detection circuit 912. The signal delay circuit 908 provides an adjustable delay to the I signal and the Q signal, and assists in controlling the relative alignment between the differential analog envelope signals ENV_p and ENV_n provided to the envelope tracker 902 and the RF signal RF provided to the power amplifier 903. The amount of delay provided by the signal delay circuit 908 is controlled based on the amount of intermodulation in the adjacent band detected by the intermodulation detection circuit 912. IN The signal delay circuit 908 provides an adjustable delay to the I signal and the Q signal, and assists in controlling the relative alignment between the differential analog envelope signals ENV_p and ENV_n provided to the envelope tracker 902 and the RF signal RF provided to the power amplifier 903. The amount of delay provided by the signal delay circuit 908 is controlled based on the amount of intermodulation in the adjacent band detected by the intermodulation detection circuit 912. The signal delay circuit 908 provides an adjustable delay to the I signal and the Q signal, and assists in controlling the relative alignment between the differential analog envelope signals ENV_p and ENV_n provided to the envelope tracker 902 and the RF signal RF provided to the power amplifier 903. The amount of delay provided by the signal delay circuit 908 is controlled based on the amount of intermodulation in the adjacent band detected by the intermodulation detection circuit 912. The signal delay circuit 908 provides an adjustable delay to the I signal and the Q signal, and assists in controlling the relative alignment between the differential analog envelope signals ENV_p and ENV_n provided to the envelope tracker 902 and the RF signal RF provided to the power amplifier 903. The amount of delay provided by the signal delay circuit 908 is controlled based on the amount of intermodulation in the adjacent band detected by the intermodulation detection circuit 912.

[0128] The DPD circuit 909 performs digital shaping on the delayed I signal and Q signal from the signal delay circuit 908 to generate digital pre-distortion (DPD) I signals and Q signals. In the illustrated embodiment, the DPD provided by the DPD circuit 909 is controlled based on the amount of intermodulation detected by the intermodulation detection circuit 912. The DPD circuit 909 serves to reduce the distortion of the power amplifier 903 and / or increase the efficiency of the power amplifier 903. The DPD circuit 909 performs digital shaping on the delayed I signal and Q signal from the signal delay circuit 908 to generate digital pre-distortion (DPD) I signals and Q signals. In the illustrated embodiment, the DPD provided by the DPD circuit 909 is controlled based on the amount of intermodulation detected by the intermodulation detection circuit 912. The DPD circuit 909 serves to reduce the distortion of the power amplifier 903 and / or increase the efficiency of the power amplifier 903. The DPD circuit 909 performs digital shaping on the delayed I signal and Q signal from the signal delay circuit 908 to generate digital pre-distortion (DPD) I signals and Q signals. In the illustrated embodiment, the DPD provided by the DPD circuit 909 is controlled based on the amount of intermodulation detected by the intermodulation detection circuit 912. The DPD circuit 909 serves to reduce the distortion of the power amplifier 903 and / or increase the efficiency of the power amplifier 903. The DPD circuit 909 performs digital shaping on the delayed I signal and Q signal from the signal delay circuit 908 to generate digital pre-distortion (DPD) I signals and Q signals. In the illustrated embodiment, the DPD provided by the DPD circuit 909 is controlled based on the amount of intermodulation detected by the intermodulation detection circuit 912. The DPD circuit 909 serves to reduce the distortion of the power amplifier 903 and / or increase the efficiency of the power amplifier 903. The DPD circuit 909 performs digital shaping on the delayed I signal and Q signal from the signal delay circuit 908 to generate digital pre-distortion (DPD) I signals and Q signals. In the illustrated embodiment, the DPD provided by the DPD circuit 909 is controlled based on the amount of intermodulation detected by the intermodulation detection circuit 912. The DPD circuit 909 serves to reduce the distortion of the power amplifier 903 and / or increase the efficiency of the power amplifier 903. The DPD circuit 909 performs digital shaping on the delayed I signal and Q signal from the signal delay circuit 908 to generate digital pre-distortion (DPD) I signals and Q signals. In the illustrated embodiment, the DPD provided by the DPD circuit 909 is controlled based on the amount of intermodulation detected by the intermodulation detection circuit 912. The DPD circuit 909 serves to reduce the distortion of the power amplifier 903 and / or increase the efficiency of the power amplifier 903.

[0129] The I / Q modulator 910 receives the digitally pre-distorted I and Q signals and these signals are processed to generate an RF signal RF IN . For example, the I / Q modulator 910 may include a DAC configured to convert the digitally pre-distorted I and Q signals into analog form , a mixer to up-convert the analog I and Q signals to radio frequency (RF) , and a signal combiner to combine the up-converted I and Q signals into an RF signal RF . In a given implementation, the I / Q modulator 910 IN may include one or more filters configured to filter the frequency components of the signals being processed .

[0130] The envelope delay circuit 921 delays the I and Q signals from the baseband processor 907 . Additionally, the CORDIC circuit 922 processes the delayed I and Q signals and generates a digital envelope signal representative of the envelope of the RF signal RF IN . Although FIG. 12 shows one implementation using the CORD IC circuit 922, an analog envelope signal can be obtained in other ways .

[0131] The shaping circuit 923 operates to shape the digital envelope signal to enhance the performance of the communication system 950 . In a given implementation, the shaping circuit 923 includes a shaping table that maps each level of the digital envelope signal to a corresponding shaped envelope signal level . Envelope shaping helps to assist in the control of the linearity, distortion, and / or efficiency of the power amplifier 903 to obtain .

[0132] In the illustrated embodiment, the shaped envelope signal is a digital signal that is converted by the DAC924 into a differential analog envelope signal. Additionally, the differential analog envelope signal is filtered by the reconstruction filter 925 to generate differential analog envelope signals ENV_p and ENV_n that are suitable for use by the differential envelope amplifier of the MLS envelope tracker 902. In a given implementation, the reconstruction filter 925 includes a differential low-pass filter.

[0133] Continuing to refer to FIG. 12, the MLS envelope tracker 902 receives the differential analog envelope signal from the reconstruction filter 925 and the battery voltage V from the battery 901, and uses the differential analog envelope signals ENV_p and ENV_n to generate a power amplifier supply voltage V BATT for the power amplifier 903. The power amplifier supply voltage V varies in relation to the envelope of the RF signal RF CC_PA . The power amplifier 903 receives the RF signal RF CC_PA from the I / Q modulator 910 and provides the amplified RF signal RF to the antenna 906 via the duplexing IN switching circuit 905 in this example. IN OUT The directional coupler 904 is disposed between the output of the power amplifier 903 and the input of the duplexing switching circuit 905 to allow measurement of the output power of the power amplifier 903 without including the insertion loss of the duplexing switching circuit 90

[0134] 5. The detected output signal of the directional coupler 9 04 is provided to the observation receiver 911. The observation receiver 911 provides downconversion to generate the downconverted I and Q signals. mixer to provide downconversion to generate the downconverted I and Q signals. a device, and a DAC that generates I observation signals and Q observation signals from the down-converted I signals and Q signals may be included.

[0135] The intermodulation detection circuit 912 determines the intermodulation product of the I observation signals and Q observation signals and the I signals and Q signals from the baseband processor 907. Additionally, the intermodulation detection circuit 912 controls the DPD provided by the DPD circuit 909 and / or the delay of the signal delay circuit 908 to control the relative alignment of the differential analog envelope signals ENV_p, ENV_n and the RF signal RF IN In other embodiments, the intermodulation detection circuit 912 additionally or alternatively controls the delay of the signal delay circuit 921.

[0136] By including the feedback path from the output of the power amplifier 903 and the baseband, the I signals and Q signals can be dynamically adjusted to optimize the operation of the communication system 950. For example, by configuring the communication system 950 in this manner, power control, compensation for transmitter impairments, and / or the execution of DPD are assisted.

[0137] Although shown as a single stage, the power amplifier 903 may include one or more stages. Furthermore, the teachings herein are also applicable to communication systems including multiple power amplifiers.

[0138] FIG. 13 is a schematic diagram of an MLS modulation system according to an embodiment. The MLS modulation system 1050 includes a modulator control circuit 1020, an MLSDC / DC converter 1025, a modulator switch bank 1027, and a decoupling capacitor bank 1030.

[0139] The MLS modulation system 1050 of FIG. 13 is suitable for incorporation into a multilevel envelope tracker. An implementation example of a switched MLS modulator circuit is shown. However, other implementation examples of the MLS modulator circuit may also be included in the multilevel envelope tracker implemented in accordance with the teachings herein.

[0140] The MLS DC / DC converter 1025 provides DC / DC conversion of the battery voltage V BATT to generate a first regulated voltage V MLS1 a second regulated voltage V MLS2 and a third regulated voltage V MLS3 Although an example with three regulated voltages is shown, the MLS DC / DC converter 1025 may generate more or fewer regulated voltages. In a given implementation example, at least a portion of the regulated voltages is boosted relative to the battery voltage V BATT

[0141] BATT Alternatively or additionally, one or more of the regulated voltages is a buck voltage and has a voltage lower than the battery voltage V BATT

[0141] The decoupling capacitor bank 1030 assists in stabilizing the regulated voltages generated by the MLS DC / DC converter 1025. For example, the decoupling capacitor bank 1030 of FIG. 13 includes a first decoupling capacitor 1031 that decouples the first regulated voltage V MLS1 a second decoupling capacitor 1032 that decouples the second regulated voltage V MLS1 MLS2 and a third decoupling capacitor 1033 that decouples the third regulated voltage V MLS2 MLS3 MLS3

[0142]

[0142] ​​Continuing to refer to FIG. 13, the modulator switch bank 1027 includes a first switch 1041 connected between the output of the modulator (MO D OUT ) and the first regulated voltage V MLS1 , a second switch 1042 connected between the output of the modulator and the second regulated voltage V , and a third switch 1043 connected between the output of the modulator and the third regulated voltage V MLS2 . The modulator control unit 1020 operates to selectively open and close the switches 1041 - 1043 to control the output of the modulator. MLS3

[0143] FIG. 14 is a schematic diagram of an MLSDC / DC converter 1073 according to an embodiment. The MLS DC / DC converter 1073 includes an inductor 1075, a first switch S1, a second switch S2, a third switch S3, a fourth switch S4, a fifth switch S5, and a sixth switch S6. The MLS DC / DC converter 1073 further includes a control circuit (not shown in FIG. 14) for providing regulation of the opening and closing of the switches. LS DC / DC converter 1073 includes an inductor 1075, a first switch S1, a second switch S2, a third switch S3, a fourth switch S4, a fifth switch S5, and a sixth switch S6. The MLS DC / DC converter 1073 further includes a control circuit (not shown in FIG. 14) for providing regulation of the opening and closing of the switches.

[0144] The MLS DC / DC converter 1073 of FIG. 14 shows an implementation example of an MLS DC / DC converter suitable for incorporation into a multilevel envelope tracker. However, the multilevel envelope tracker implemented in accordance with the teachings herein may include other implementation examples of the MLS DC / DC converter.

[0145]

[0145] In the illustrated embodiment, the first switch S1 includes a first end electrically connected to the battery voltage V BATT and a second end electrically connected to the first end of the second switch S2 and the first end of the inductor 1075. The second switch S2 further includes a first supply or ground supply V G ND FIG. 14 shows a power supply using a ground supply and a battery voltage. Although the teachings herein show the configuration of a DC / DC converter powered by The invention is also applicable to DC / DC converters powered using any suitable power supply. The inductor 1075 is further connected to the first terminals of the third switch S3 to the sixth switch S6. The third switch S3 further includes a second end electrically connected to the ground supply V GND The fourth switch, the fifth switch and the sixth switch S4 also include a second end electrically connected to the 〜S6 respectively represent the first regulated voltage, the second regulated voltage and the third regulated voltage V ML S1 , V MLS2 and V MLS3 and a second end configured to generate each of the

[0146] The first switch to the sixth switch S1 to S6 adjust the regulated voltage to a specific error of the target voltage level. An example having three regulated voltages is shown in Figure 1. Although shown, the MLS DC / DC converter 1073 may have more or less The present invention may be implemented to generate a regulated voltage that is not

[0147] In the illustrated embodiment, the MLS DC / DC converter 1073 converts the battery voltage V BATT and / or to generate a regulated boost voltage greater than the battery voltage V BATT twist It operates as a buck-boost converter that can be operated to generate a very small regulated buck voltage. However, other implementations are possible.

[0148] Figure 15 is a schematic diagram of an example of the timing for MLS DC / DC conversion. As shown in Figure 15, the width of the adjustment cycle can be used to control the voltage level of the regulated voltage generated by the MLS DC / DC conversion. For example, one MLS regulated voltage can be associated with a period t1, while a second regulated voltage can be associated with a different period t2. Additionally, a non-overlapping period tovlp can be used to avoid crosstalk current between different voltage levels. In a given implementation example here, one or more adjustment cycles (e.g., t1 and / or t2) and / or one or more non-overlapping periods (e.g., tovlop) can be digitally controllable. In a given

[0149] implementation example, the delay is controlled based on a digital state machine and / or other suitable circuitry. The regulated voltage generated by the MLS DC / DC conversion can be selectively provided to the modulator output filter by the modulator. In the illustrated example, the modulator output filter is depicted as including shunt capacitors C1 and C2 and series inductors L1 and 2. However, other implementation examples of the modulator output filter are possible.

[0150] Figure 16 is a schematic diagram of an example of MLS envelope tracking for a continuous wave signal. The example shown is for a continuous wave signal having a frequency of approximately 100 MHz and a corresponding period of approximately 10 ns. An example of a suitable MLS voltage level for the signal is shown. At the end However, other implementation examples of the modulator output filter are possible.

[0151] Figure 16 is a schematic diagram of an example of MLS envelope tracking for a continuous wave signal. The example shown is for a continuous wave signal having a frequency of approximately 100 MHz and a corresponding period of approximately 10 ns. An example of a suitable MLS voltage level for the signal is shown. At the end

[0152] End

[0153] Some of the above embodiments have provided examples related to mobile devices. However , the principles and advantages of these embodiments can be used for any other system or device that requires envelope tracking.

[0154] Unless the context clearly requires otherwise, throughout the specification and claims , terms such as "including", "comprising", etc. should be construed in an inclusive sense opposite to an exclusive or exhaustive sense, i.e., in the sense of "including but not limited to". Here generally the term "coupled" is used to refer to the possibility that two or more elements may be either directly connected or connected via one or more intermediate elements. Similarly, here generally the term "connected" is also used to refer to the possibility that two or more elements may be either directly connected or connected via one or more intermediate elements. In addition, when used in this application , the terms "herein", "above", "below", and terms of similar meaning refer to the entire application and not to any particular part of the application. Where the context permits , the terms in the above detailed description using singular or plural numbers may each include the plural or singular number as well. The terms "or" and "and / or" referring to a list of two or more items cover the following interpretations of that term, i.e., any of the items in the list, all of the items in the list, and any combination of the items in the list. .

[0155] Furthermore, unless specifically described or understood otherwise within the context in which it is used , especially "can", "may", "may be", "might", "for example ", "such as", "conditional language used herein generally intends that a given embodiment includes a given feature, element, and / or condition while other embodiments do not. That is, such conditional language generally does not necessarily imply that a feature, element, and / or condition exists in any manner required by one or more embodiments, or that one or more embodiments include these features, elements, and / or conditions with or without the author's input or prompt, or the logic for determining whether or not they should be included in any particular embodiment, or whether or not they should be performed in any particular embodiment.

[0156] The above description of embodiments of the present invention is not intended to be exhaustive or to limit the present invention to the exact form disclosed. Specific embodiments and examples of the present invention have been described above for illustrative purposes, but as will be recognized by those skilled in the art, various equivalent modifications are possible within the scope of the present invention. For example, while a process or block is presented in a given order, alternative embodiments may execute a routine having steps in a different order or use a system having blocks, and some processes or blocks may be deleted, moved, added, subdivided, combined, and / or modified. These processes or blocks may each be implemented in various different manners. Also, while a process or block may be shown as being executed serially, these processes or blocks may instead be executed in parallel or at different times.

[0157] The teachings of the present invention provided herein are not necessarily limited to other systems It can be applied to the stem. The elements and operations of the various embodiments described above may be combined to provide further embodiments.

[0158] Although certain embodiments of the present invention have been described, these embodiments are presented by way of example only and are not intended to limit the scope of the disclosure. In fact, the novel methods and systems described herein may be embodied in various other forms, and furthermore, various omissions, substitutions, and changes in the forms of the methods and systems described herein may be made without departing from the spirit of the disclosure. The appended claims and their equivalents are intended to cover forms or modifications that fall within the scope and spirit of the disclosure. The novel methods and systems described herein may be embodied in various other forms, and furthermore, various omissions, substitutions, and changes in the forms of the methods and systems described herein may be made without departing from the spirit of the disclosure. The appended claims and their equivalents are intended to cover forms or modifications that fall within the scope and spirit of the disclosure. The appended claims and their equivalents are intended to cover forms or modifications that fall within the scope and spirit of the disclosure. ​​

Claims

1. An envelope tracking system comprising: a power amplifier configured to amplify a radio frequency signal and receive power from a power amplifier supply voltage; an envelope tracker configured to generate the power amplifier supply voltage based on an analog envelope signal corresponding to an envelope of the radio frequency signal; wherein the envelope tracker comprises: a DC / DC converter configured to output a plurality of regulated voltages; a modulator configured to generate a modulator output voltage at the output based on the plurality of regulated voltages and the analog envelope signal; a modulator output filter coupled between the output of the modulator and the power amplifier supply voltage; wherein the modulator is configured to generate the modulator output voltage based on a comparison of the analog envelope signal with a plurality of signal thresholds. An envelope tracking system.

2. The envelope tracking system of claim 1, wherein the modulator comprises a plurality of switches selectively activated based on a comparison of the analog envelope signal with the plurality of signal thresholds.

3. The envelope tracker further comprises a plurality of modulators including the modulator, and a plurality of modulator output filters including the modulator output filter, wherein each of the plurality of modulators is coupled to the power amplifier supply voltage via a corresponding one of the plurality of modulator output filters. The envelope tracking system of claim 1.

4. The envelope tracking system of claim 3, wherein the number of active ones of the plurality of modulators is selected based on a comparison of the analog envelope signal with the plurality of signal thresholds.

5. The envelope tracking system of claim 1, wherein the modulator is configured to receive the analog envelope signal via a Mobile Industry Peripheral Interface Analog (MIPI-AXI) standard interface for envelope tracking.

6. The envelope tracking system of claim 1, wherein the analog envelope signal is a differential envelope signal.

7. The envelope tracking system of claim 6, wherein the modulator comprises a differential envelope amplifier configured to amplify the differential envelope signal to generate a single-ended envelope signal, and a plurality of comparators each configured to compare the single-ended envelope signal with a corresponding one of the plurality of signal thresholds.

8. The envelope tracking system of claim 1, wherein each of the plurality of signal thresholds is controllable.

9. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The envelope tracker further includes a DC path filter coupled between the DC voltage and the power amplifier supply voltage. The envelope tracking system of claim 1, including a DC path filter. **Claim 10** The DC / DC converter of claim 9 is further configured to generate the DC voltage. The envelope tracking system of claim 9. **Claim 11** The DC path filter of claim 9 includes at least one series inductor and at least one shunt capacitor. The envelope tracking system of claim 9. **Claim 12** The modulator output filter of claim 1 includes at least one series inductor and at least one shunt capacitor. The envelope tracking system of claim 1. **Claim 13** The modulator output filter of claim 12 further includes a DC block capacitor serially connected between the modulator output voltage and the power amplifier supply voltage. The envelope tracking system of claim 12. **Claim 14** An envelope tracker, comprising: a power amplifier supply voltage terminal configured to output a power supply voltage for a power amplifier; a DC / DC converter configured to output a plurality of regulated voltages based on adjusting a battery voltage; a modulator output filter; a modulator including an output coupled to the power amplifier supply voltage terminal via the modulator output filter; The modulator is configured to generate a modulator output voltage at the output based on the plurality of regulated voltages and an analog envelope signal. The modulator is configured to generate the modulator output voltage based on a comparison between the analog envelope signal and a plurality of signal thresholds. Including The modulator is configured to generate a modulator output voltage at the output based on the plurality of regulated voltages and an analog envelope signal. The modulator is configured to generate the modulator output voltage based on a comparison between the analog envelope signal and a plurality of signal thresholds. The envelope tracker is configured to generate the modulator output voltage based on a comparison between the analog envelope signal and a plurality of signal thresholds. The envelope tracker is configured to generate the modulator output voltage based on a comparison between the analog envelope signal and a plurality of signal thresholds. **Claim 15** Further including a plurality of modulators including the modulator and a plurality of modulator output filters including the modulator output filter. Each of the plurality of modulators is coupled to the power amplifier supply voltage terminal via a corresponding one of the plurality of modulator output filters. The envelope tracker of claim 14. **Claim 16** Based on a comparison between the analog envelope signal and the plurality of signal thresholds, the number of active ones among the plurality of modulators is selected. The envelope tracker of claim 15. Based on a comparison between the analog envelope signal and the plurality of signal thresholds, the number of active ones among the plurality of modulators is selected. **Claim 17** The analog envelope signal is a differential envelope signal. The modulator is configured to amplify the differential envelope signal to generate a single-ended envelope signal. The differential envelope amplifier is configured to generate a single-ended envelope signal, and each of the differential envelope amplifiers is configured to generate a single-ended envelope signal based on the single-ended envelope signal and the plurality of A plurality of comparators configured to compare with one of the corresponding signal thresholds, the envelope tracker of claim 14. **Claim 18** A mobile device, a transceiver configured to generate a radio frequency transmission signal, a front-end circuit including a power amplifier configured to amplify the radio frequency transmission signal and receive power from a power amplifier supply voltage, a power management circuit including an envelope tracker configured to generate the power amplifier supply voltage based on an analog envelope signal corresponding to the envelope of the radio frequency signal and including, wherein the envelope tracker includes a DC / DC converter configured to output a plurality of regulated voltages, a modulator configured to generate a modulator output voltage at the output based on the plurality of regulated voltages and the analog envelope signal, and a modulator output filter coupled between the output of the modulator and the power amplifier supply voltage, wherein the modulator is configured to generate the modulator output voltage based on a comparison between the analog envelope signal and a plurality of signal thresholds, a mobile device. **Claim 19** The envelope tracker further includes a plurality of modulators including the modulator and a plurality of modulator output filters including the modulator output filter, wherein each of the plurality of modulators is coupled to the power amplifier supply voltage through a corresponding one of the plurality of modulator output filters, the mobile device of claim 18. **Claim 20** The number of active ones among the plurality of modulators is selected based on a comparison between the analog envelope signal and the plurality of signal thresholds, the mobile device of claim 19. ​ ​ ​ ​

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