Abstract: Apparatus and methods for tuning a voltage controlled oscillator (VCO) are provided. In one aspect, a method of auto-tuning in a phase-locked loop includes generating a VCO clock signal using a VCO coupled to a capacitor array, dividing the VCO clock signal to generate a divided clock signal using a prescaler circuit having a selectable division ratio, controlling a value of the selectable division ratio using a first counter and a second counter of a counter module, generating a phase-frequency detector feedback signal based on a division control signal M and the divided clock signal using the counter module, counting a number of cycles of the divided clock signal that occur during a calibration interval using a cycle counter of a digital processing logic circuit, and determining the value of a capacitor array control signal based on the number of cycles counted during the calibration interval.

Abstract: According to some implementations, a power amplifier (PA) includes a common emitter configured to receive a radio-frequency (RF) signal. The PA also includes a carrier amplifier coupled to the common emitter to form a carrier cascode configuration, a collector of the carrier amplifier provided with a first supply voltage. The PA further includes a peaking amplifier coupled to the common emitter to form a peaking cascode configuration, a collector of the peaking amplifier provided with a second supply voltage greater than the first supply voltage.

Abstract: A voltage converter can be switched among two or more modes to produce an output voltage tracking a reference voltage that can be of an intermediate level between discrete levels corresponding to the modes. One or more voltages generated from a power supply voltage, such as a battery voltage, can be compared with the reference voltage to determine whether to adjust the mode. The reference voltage can be independent of the power supply voltage. Further, the voltage converter may implement frequency modulation and a pulse skipping mode to improve the efficiency of switching operational states of the voltage converter.

Abstract: A switch control circuit includes a positive voltage bias node, a voltage-regulated positive supply rail coupled to the positive voltage bias node, a charge pump coupled to a charge pump supply node, and a current source positive supply rail coupled to the charge pump supply node and configured to supply the charge pump.

Abstract: Multiband power amplifier with cascode switching. A power amplification system can include a first transistor having a base configured to receive an input radio-frequency (RF) signal and having an emitter coupled to a ground potential. The power amplification system can include a plurality of second transistors. Each one of the plurality of second transistors can have a respective emitter coupled to a collector of the first transistor and can be configured to, when biased at a respective base, output an output RF signal at a respective collector. The power amplification system can further include a biasing circuit configured to bias one or more of the plurality of second transistors based on a control signal.

Abstract: A wireless device is disclosed that can support carrier aggregation uplink (“CAUL”) communication using a single wideband coupler. A single wideband coupler that can operate or support some or all of the communication bands of the wireless device can be used in conjunction with one or more diplexers and/or filters to measure the power of individual communication bands involved in the transmission process. Further, the use of a wideband coupler and switching network to measure the transmit power from the one or more transmit paths or main paths of a wireless device can reduce the size of a transceiver and reduce the insertion loss attributed to the power measurement components compared to systems that use separate measurement systems for each transmit path. The power measurement system may occur in a separate path in electrical connection with the wideband coupler, which may therefore be termed a coupler path.

Abstract: The systems and processes described herein can reduce the footprint of the internal devices of a wireless device by combining the DC-DC supply regulator with a FEM. Further, the device footprint can be further reduced by sharing the integrated DC-DC supply regulator among multiple FEMs reducing or eliminating the use of a separate DC-DC supply regulator for each FEM of a wireless device. Moreover, in certain embodiments, by integrating the DC-DC supply regulator into a 2G FEM, power efficiency can be improved for some wireless devices. For example, the DC-DC supply regulator may be used to supply power to a PA used for high-band 2G transmission functions. Using the DC-DC supply regulator can improve power efficiency compared to systems that supply the power for the high-band 2G PA directly from the power supply (e.g., the battery).

Abstract: A power management device is disclosed, including a first DC-DC converter coupled to a first output voltage line, a second DC-DC converter coupled to a second output voltage line, a first set of switches associated with the first DC-DC converter, and a second set of switches associated with the second DC-DC converter. The power management device may further include a controller configured to toggle one or more switches of the first set of switches and one or more switches of the second set of switches, and a multi-mode radio-frequency front-end block communicatively coupled to the controller.

Abstract: The present disclosure relates to a system for biasing a power amplifier. The system can include a first die that includes a power amplifier circuit and a passive component having an electrical property that depends on one or more conditions of the first die. Further, the system can include a second die including a bias signal generating circuit that is configured to generate a bias signal based at least in part on measurement of the electrical property of the passive component of the first die.

Abstract: Apparatus and methods for envelope tracking systems are provided. In certain configurations, an envelope tracking system includes a digital filter that generates a filtered envelope signal based on a digital envelope signal representing an envelope of a radio frequency signal, a buck converter controllable by the filtered envelope signal and including an output electrically connected to a power amplifier supply voltage, a digital-to-analog converter module including an output electrically connected to the output of the buck converter and that provides an output current, and a digital shaping and delay circuit configured to generate a shaped envelope signal based on shaping the filtered envelope signal. The shaped envelope signal controls a magnitude of the output current, and the digital shaping and delay circuit controls a delay of the shaped envelope signal to align the output of the digital-to-analog converter module and the output of the buck converter.

Abstract: A switch bias control circuit includes a level shifter and voltage regulator circuitry configured to receive a voltage reference signal, provide a first voltage output at a first node and provide a second voltage output at a second node, the first node and the second node being at least partially isolated from one another. coupling circuitry couples the first node to the level shifter and couples the second node to a negative voltage generator.

Abstract: A system for power amplifier over-voltage protection includes a power amplifier configured to receive a system voltage, a bias circuit configured to provide a bias signal to the power amplifier, and a power amplifier over-voltage circuit configured to interrupt the bias signal when the system voltage exceeds a predetermined value, while the system voltage remains coupled to the power amplifier.

Abstract: Embodiments disclosed herein relate to a bias circuit that uses Schottky diodes. Typically, a bias circuit will include a number of transistors used to generate a bias voltage or a bias current for a power amplifier. Many wireless devices include power amplifiers to facilitate processing signals for transmission and/or received signals. By substituting the bias circuit design with a design that utilizes Schottky diodes, the required battery voltage of the bias circuit may be reduced enabling the use of lower voltage power supplies.

Abstract: Apparatus and methods for envelope tracking systems are disclosed herein. In certain implementations, an envelope tracking system for generating a power amplifier supply voltage for a power amplifier is provided. The envelope tracking system includes a DC-to-DC converter that generates a regulated voltage from a battery voltage and controls a voltage of the regulated voltage using a low frequency feedback signal. The envelope tracking system further includes an error amplifier that generates an output current using an envelope signal and a high frequency feedback signal. The low frequency feedback signal is based on a low frequency component of the power amplifier supply voltage and the high frequency feedback signal is based on a high frequency component of the power amplifier supply voltage. The error amplifier generates the power amplifier supply voltage by adjusting the magnitude of the regulated voltage using the output current.

Abstract: Switched-mode power supply with switch resizing. A power converter can include an inductor coupled between an input node and an intermediate node, a semiconductor device coupled between the intermediate node and an output node, and a plurality of drive transistors. Each one of the plurality of drive transistors can have a drain coupled to the intermediate node and a source coupled to a ground potential.

Abstract: A voltage converter can be switched among two or more modes to produce an output voltage tracking a reference voltage that can be of an intermediate level between discrete levels corresponding to the modes. One or more voltages generated from a power supply voltage, such as a battery voltage, can be compared with the reference voltage to determine whether to adjust the mode. The reference voltage can be independent of the power supply voltage.

Abstract: In accordance with some embodiments, the present disclosure relates to a dual mode control interface that can be used to provide both a radio frequency front end (RFFE) serial interface and a two-mode general purpose input/output (GPIO) interface within a single digital control interface die. In certain embodiments, the dual mode control interface, or digital control interface, can communicate with a power amplifier. Further, the dual mode control interface can be used to set the mode of the power amplifier.

Abstract: In a voltage converter, a mode configuration is selected in response to a mode control signal using a switch matrix having two or more mode configurations. Each mode configuration corresponds to one of two or more output signal voltages. The output signal is compared with a reference signal to produce a direction comparison signal. The direction comparison signal is used to produce the mode control signal.

Abstract: According to some implementations, a power amplifier (PA) includes a common emitter configured to receive a radio-frequency (RF) signal. The PA also includes a carrier amplifier coupled to the common emitter to form a carrier cascode configuration, a collector of the carrier amplifier provided with a first supply voltage. The PA further includes a peaking amplifier coupled to the common emitter to form a peaking cascode configuration, a collector of the peaking amplifier provided with a second supply voltage greater than the first supply voltage.

Abstract: Power amplification system with variable supply voltage. A power amplification system can include a power amplifier and a boost converter configured to provide a supply voltage to the power amplifier. The power amplification system can include a control system configured to provide a boost converter control signal to the boost converter to adjust the supply voltage based on a parameter associated with the power amplifier.