Abstract: An envelope tracking (ET) amplifier apparatus is provided. The ET amplifier apparatus includes an amplifier circuit configured to amplify a radio frequency (RF) signal based on a modulated voltage. In examples discussed herein, the amplifier circuit is co-located with a local voltage amplifier circuit configured to supply the modulated voltage such that a trace inductance between the amplifier circuit and the local voltage amplifier circuit can be reduced to below a defined threshold. By co-locating the amplifier circuit with the local voltage amplifier circuit to reduce a coupling distance between the amplifier circuit and the local voltage amplifier circuit and thus the trace inductance associated with the coupling distance, it may be possible to reduce degradation in the modulated voltage. As a result, it may be possible to improve efficiency and maintain linearity in the amplifier circuit, particularly when the RF signal is modulated at a higher modulation bandwidth.

Abstract: An apparatus that includes a tracking amplifier having an amplifier output terminal coupled to an output voltage node and an envelope input terminal configured to receive an envelope signal of a radio frequency signal is disclosed. A multi-level voltage converter has a switched voltage terminal coupled to the output voltage node and a converter control input terminal configured to receive a converter control signal. A control signal multiplexer has a converter control output terminal coupled to the converter control input terminal, a first converter signal input terminal configured to receive a first converter control signal corresponding to a lower envelope modulation bandwidth, a second converter signal input terminal configured to receive a second converter control signal corresponding to a higher envelope modulation bandwidth, and a converter control signal selector terminal configured to receive a control selector signal for selecting between the first and second converter control signals.

Abstract: A power switch with a bootstrap driver for continuous time operation is disclosed. In an exemplary aspect, the power switch selectively connects power management circuitry to one or more power amplifier stages in a radio frequency (RF) front end. The bootstrap driver provides a constant gate to source voltage during an enabled state of the power switch such that a switching element can remain closed with near-constant closed switch resistance in the presence of varying signals (e.g., varying power signals) passing through the power switch. The bootstrap driver can use a variable clock frequency to quickly close the power switch and resistor-capacitor (RC) filtering to reduce noise contribution to the signal path through the power switch. In some examples, a constant voltage reference provides battery independent voltage control of the gate to source voltage of the power switch.

Abstract: Disclosed is a radio frequency multiplexer having an M number of multiplexer branches each having an outer port terminal coupled to a common outer node, wherein M is a positive counting number. Each of the M number of multiplexer branches comprises a multi-bandpass filter configured to filter an N number of bands multiplexed by the radio frequency multiplexer to pass an individual group of N/M bands, wherein N is a positive counting number greater than one and equal to a total number of bands to be multiplexed. Each of the M number of multiplexer branches further includes an N/M number of resonator branches each having a band port terminal configured to pass a single band and an inner branch terminal coupled to an inner port terminal of the multi-bandpass filter at a common inner node.

Abstract: An adaptive frequency equalizer for wide modulation bandwidth envelope tracking (ET) is provided. In this regard, an ET integrated circuit (ETIC) provides an ET power signal for one or more power amplifiers (PAs). A voltage error can occur in the ET power signal due to variable impedance sources, such as a variable load impedance at the PA and a variable trace inductance between the ETIC and the PA. The adaptive frequency equalizer disclosed herein works to adaptively correct for such voltage errors to provide improved overall power signal tracking at the PA, especially where there is a large trace inductance from the ETIC being located several centimeters (cm) away from the PA. Thus, embodiments of the adaptive frequency equalizer enhance ET performance for radio frequency (RF) systems having a modulation bandwidth of 100 megahertz (MHz) or above.

Abstract: A dual-input envelope tracking (ET) integrated circuit (ETIC) and related apparatus are provided. The dual-input ETIC includes an ET voltage circuit configured to generate an ET voltage based on an ET voltage and a first set of parameters. The ET voltage may be provided to a power amplifier circuit(s) for amplifying a radio frequency (RF) signal(s) in an ET power range. The dual-input ETIC also includes a target voltage processing circuit configured to generate the ET target voltage based on a second set of parameters. The dual-input ETIC further includes a control circuit configured to determine the first set of parameters and the second set parameters based at least on the ET power range of the power amplifier circuit(s). As such, it may be possible to optimize the dual-input ETIC performance in a wide-range of modulation bandwidth, thus helping to improve linearity and efficiency of the power amplifier circuit(s).

Abstract: A tunable notch filter is disclosed with a first acoustic resonator coupled in series with a first inductive element between a filter input node and a filter output node. A first capacitor is coupled in parallel with the first acoustic resonator and the first inductive element. In at least one embodiment, the first capacitor is configured to have variable capacitance that is electronically tunable by way of an electronic controller. A second acoustic resonator is coupled in series with a second inductive element between the filter output node and a signal ground node. A second capacitor is coupled in parallel with the second inductive element. In at least one embodiment, the second capacitor is electronically tunable. The tunable notch filter is configured to provide a highly selective notch filter response between the filter input node and the filter output node with high attenuation.

Abstract: An envelope tracking (ET) amplifier circuit is provided. The voltage mDPD circuit is provided in an ET amplifier circuit and configured to determine a voltage deviation relative to an ET modulated target voltage signal, execute an mDPD polynomial in one or more iterations to extract an mDPD coefficient(s), and adjust a time-variant target voltage envelope of the ET modulated target voltage signal based on the mDPD coefficient(s) extracted in each of the mDPD iterations to reduce the voltage deviation to a predefined threshold. By reducing the voltage deviation in the ET modulated voltage, it is possible improve linearity (e.g., gain linearity) of the ET amplifier circuit, which can lead to reduced power consumption and improved radio frequency (RF) performance.

Abstract: Envelope tracking circuit and related power amplifier system are provided. In one aspect, an ET circuit is configured to generate a first number of ET modulated voltages based on a second number of target voltages and output the first number of ET modulated voltages via a third number of voltage outputs. In another aspect, the ET circuit can be provided in a power amplifier system including a transceiver circuit(s) and a number of power amplifier circuits. In examples discussed herein, the ET circuit may receive the second number of target voltages from the transceiver circuit(s) and provide the first number of ET modulated voltages to the power amplifier circuits for amplifying a radio frequency (RF) signal(s). By providing the ET circuit in the power amplifier system, it is possible to flexibly enable ET power management based on any number of transceiver circuits and for any number of power amplifier circuits.

Abstract: A diplexer circuit is provided. The diplexer circuit, which includes a pair of hybrid couplers and a filter circuit, can be configured to support dual-connect (DC) communications on a pair of signal bands separated by a narrower transition band (e.g., ?200 MHz). In examples discussed herein, one of the signal bands is associated with a narrower fractional bandwidth (e.g., <13%) than the other signal band. In this regard, the filter circuit can be opportunistically configured to operate based on the narrower fractional bandwidth. By configuring the filter circuit to operate based on the narrower fractional bandwidth, it is possible to eliminate the need for supporting the wider fractional bandwidth in the diplexer circuit. As a result, it may be possible to implement the diplexer circuit using conventional filters to support DC communications on signal bands associated with a wider fractional bandwidth(s) and separated by a narrower transition band.

Abstract: Embodiments of the disclosure include a multi-band radio frequency (RF) circuit. The multi-band RF circuit includes multiple antenna ports coupled to multiple antennas and an antenna swapping circuit coupled to the multiple antenna ports. Control circuitry in the multi-band RF circuit controls the antenna swapping circuit to selectively couple various transmit and/or receive filters with any one or more of the multiple antenna ports to support uplink carrier aggregation (ULCA) and/or multiple-input multiple-output (MIMO) operations with a minimum number of transmit and receive filters. Transmit filters of adjacent RF bands are physically separated, but disposed in proximity, in the multi-band RF circuit to help reduce intermodulation products between the adjacent RF bands during the ULCA operation. As a result, it is possible to improve RF performance of ULCA and MIMO operations, without increasing complexity, cost, and footprint of the multi-band RF circuit.

Abstract: A multi-polarization millimeter wave (mmWave) transmitter/receiver (TX/RX) architecture with shared power amplifiers (PAs) is provided. This architecture provides a transceiver which uses shared PAs to reduce the number of TX and PA stages required for multi-polarization transmission in mmWave radio frequency (RF) devices. Embodiments provide an array of switching channels which selectively connect a shared TX and shared PA to two or more antennas in antenna arrays having different polarizations (e.g., a dipole antenna array and a patch antenna array). This approach provides a dual polarization or multi-polarization mmWave transceiver having a reduced number of components which results in a smaller size, improved power efficiency, and improved power heat dissipation.

Abstract: A multi-radio access technology (RAT) envelope tracking (ET) amplifier apparatus is provided. The multi-RAT ET amplifier apparatus may be configured to enable concurrent communication of at least two radio frequency (RF) signals associated with at least two different RATs. Specifically, the multi-RAT ET amplifier apparatus includes an ET integrated circuit (IC) (ETIC) and a distributed ETIC (DETIC) configured to generate respective ET voltages for amplifying the two RF signals. In addition, the DETIC can be configured to utilize certain circuit(s) in the ETIC to help reduce a footprint of the DETIC. By amplifying the two different RF signals based on the respective ET voltages and sharing certain circuit(s) between the ETIC and the DETIC, it may be possible to improve overall efficiency and heat dissipation in the multi-RAT ET amplifier apparatus concurrent to reducing the footprint of the DETIC.

Abstract: A multi-level voltage circuit and related apparatus are provided. The multi-level voltage circuit is configured to provide an average power tracking (APT) voltage to an amplifier circuit for amplifying a radio frequency (RF) signal, which can be modulated in a number of orthogonal frequency division multiplexing (OFDM) symbols. The RF signal may experience power fluctuations from one OFDM symbol to another and the multi-level voltage circuit may need to adjust the APT voltage accordingly. In examples discussed herein, when the APT voltage needs to increase from a present value to a higher future value at a predetermined effective time, the multi-level voltage circuit may start increasing the APT voltage from the present value toward the future value ahead of the predetermined effective time. As such, it may be possible to ramp up the APT voltage in a timely fashion to help improve linearity and efficiency of the amplifier circuit.

Abstract: An envelope tracking (ET) integrated circuit (IC) (ETIC) is provided. The ETIC includes a number of ET circuits coupled to a number of amplifier circuits configured to amplify a radio frequency signal based on a number of ET voltages, respectively. The ET circuits are configured to generate the ET voltages based on a number of ET target voltages, respectively. The ETIC includes a reference ET circuit configured to generate a reference ET voltage based on a maximum ET target voltage among the ET target voltages. A selected ET circuit(s) among the ET circuits may be configured to not generate a respective ET voltage(s) but instead forward the reference ET voltage to a respective amplifier circuit(s) as the respective ET voltage(s). Hence, it may be possible to partially or completely turn off the selected ET circuit(s) to help reduce peak battery current and improve heat dissipation in an ET amplifier apparatus.

Abstract: An electrical current measurement circuit is provided. The electrical current measurement circuit is configured to receive a sense current proportionally related to an electrical current of interest to continuously charge a capacitor to a sense voltage. The electrical current measurement circuit is configured to determine whether the sense voltage reaches a predefined voltage threshold and reduce the sense voltage to below the predefined voltage threshold in response to the sense voltage reaching the predefined voltage threshold. The electrical current measurement circuit counts each occurrence of the sense voltage reaching the predefined voltage threshold and quantifies the electrical current based on a total count of the sense voltage reaching the predefined voltage threshold during the predefined measurement period.

Abstract: A PA power supply, which includes a first ET power supply, power supply control circuitry, a first PMOS switching element, and a second PMOS switching element, is disclosed. During a first operating mode, the power supply control circuitry selects an OFF state of the first PMOS switching element, selects an ON state of the second PMOS switching element, and adjusts a voltage of a first switch control signal to maintain the OFF state of the first PMOS switching element using a voltage at a source of the first PMOS switching element and a voltage at a drain of the first PMOS switching element; the PA power supply provides a first PA power supply signal; and the first ET power supply provides a first ET power supply signal, such that the first PA power supply signal is based on the first ET power supply signal.

Abstract: A radio frequency (RF) front-end circuit is provided. A power management circuit is configured to output a first modulated voltage, a second modulated voltage, a first bias voltage, and a second bias voltage via a first voltage port(s), a second voltage port(s), a first bias voltage port(s), and a second bias voltage port(s), respectively. An amplifier circuit(s) is configured to amplify an RF signal based on a selected modulated voltage and a selected bias voltage outputted by a selected voltage port and a selected bias voltage port, respectively. The power management circuit can be controlled to dynamically increase the selected bias voltage at the selected bias voltage port in case the selected bias voltage drops below a defined bias voltage threshold. As such, it may be possible to maintain the selected bias voltage at a desirable level, thus enabling the amplifier circuit(s) to operate with improved linearity and efficiency.

Abstract: An envelope tracking (ET) system is provided. The ET amplifies a radio frequency (RF) signal correspond to an amplitude bandwidth exceeding a voltage modulation bandwidth limitation of the ET system. The ET system compresses the amplitude bandwidth to match the voltage modulation bandwidth of the ET system. More specifically, the ET system compresses a predefined voltage waveform, which tracks time-variant amplitudes of a digital form of the RF signal, to generate a modified voltage waveform at a reduced bandwidth. To ensure that signal distortion(s) resulted from the bandwidth compression can be corrected, the ET system nonlinearly modifies predefined amplitude(s) of the predefined voltage waveform to generate modified amplitude(s) of the modified voltage waveform that is never less than the predefined amplitude(s) of the predefined voltage waveform. As such, the ET system can amplify the RF signal with improved linearity and efficiency, without degrading spectral performance of the RF signal.

Abstract: A group delay optimization circuit is provided. The group delay optimization circuit receives a first signal (e.g., a voltage signal) and a second signal (e.g., a current signal). Notably, the first signal and the second signal may experience different group delays that can cause the first signal and the second signal to misalign at an amplifier circuit configured to amplify a radio frequency (RF) signal. The group delay optimization circuit is configured to determine a statistical indicator indicative of a group delay offset between the first signal and the second signal. Accordingly, the group delay optimization circuit may minimize the group delay offset by reducing the statistical indicator to below a defined threshold in one or more group delay optimization cycles. As a result, it may be possible to pre-compensate for the group delay offset in the RF signal, thus helping to improve efficiency and linearity of the amplifier circuit.