A multi-band power amplifier module includes at least one transmission input terminal, at least one power amplifier circuit that receives a first transmission signal and a second transmission signal through the at least one transmission input terminal, a first filter circuit that allows the first transmission signal to pass therethrough, a second filter circuit that allows the second transmission signal to pass therethrough, at least one transmission output terminal through which the first and second transmission signals output from the first and second filter circuits are output, a transmission output switch that outputs each of the first and second transmission signals output from the at least one power amplifier circuit to the first filter circuit or the second filter circuit, and a first tuning circuit that adjusts impedance matching between the at least one power amplifier circuit and the at least one transmission output terminal.

A front-end module includes: a first front-end circuit that transmits signals in a first band in a CA mode; and a second front-end circuit that transmits signals in a second band in the CA mode. The second front-end circuit includes a second quadplexer for the first and second bands. The first front-end circuit includes: a first quadplexer for the first and second bands; and an impedance variable circuit that is connected to a transmission terminal that is included in the first quadplexer and corresponds to the second band. In the CA mode, the impedance variable circuit serves as a reflection circuit that causes reflection of transmission waves in the second band. In a non-CA mode, the impedance variable circuit serves as a matching circuit that transmits or absorbs transmission waves in the second band.

An equalizer circuit in an envelope tracking (ET) integrated circuit (ETIC) is disclosed. The ETIC (26) is configured to generate an ET voltage based on a target voltage (VTGT) for amplifying a radio frequency (RF) signal(s). Since the ETIC has inherent impedance and group delay that can cause distortion in the ET voltage, an equalizer circuit (24) is provided in the ETIC to equalize the target voltage prior to generating the ET voltage. Specifically, the equalizer circuit generates an equalized target voltage to offset the inherent impedance and a modified target voltage to mitigate the group delay. Accordingly, the equalizer circuit can output a processed target voltage, which can include the equalized target voltage and/or the modified target voltage, for generating the ET voltage. As a result, it is possible to reduce distortion resulted from the inherent impedance and group delay, especially when the RF signal(s) is modulated in a wide modulation bandwidth.

Envelope trackers providing compensation for power amplifier output load variation are provided herein. In certain configurations, a radio frequency (RF) system includes an antenna, a power amplifier that receives a radio frequency signal and outputs an amplified radio frequency signal to the antenna, a plurality of detectors coupled to the power amplifier and operable to generate a plurality of detection signals, and an envelope tracker that controls a supply voltage of the power amplifier based on an envelope of the radio frequency signal. The envelope tracker processes the plurality of detection signals to generate a load variation detection signal indicating a change in an output load of the power amplifier arising from a change in a voltage standing wave ratio (VSWR) of the antenna. Additionally, the envelope tracker adjusts a gain of the power amplifier based on the load variation detection signal.

Apparatus and methods for LNAs with mid-node impedance networks are provided herein. In certain configurations, an LNA includes a mid-node impedance circuit including a resistor and a capacitor electrically connected in parallel, a cascode device electrically connected between an output terminal and the mid-node impedance circuit, and a transconductance device electrically connected between the mid-node impedance circuit and ground. The transconductance device amplifies a radio frequency signal received from an input terminal. The LNA further includes a feedback bias circuit electrically connected between the output terminal and the input terminal and operable to control an input bias voltage of the transconductance device.

The present invention concerns a programmable power amplifier comprising:

an amplifier core transistor circuit connected to an amplifier output node; a switch connected to the amplifier core transistor circuit, the switch being configured to switch on and off the amplifier core transistor circuit; and a feedback circuit of the amplifier core transistor circuit. The feedback circuit comprises a digital-to-analog converter and an operational amplifier having a first input node configured to receive a first reference signal; a second input node connected to the digital-to-analog converter; and an output node for outputting an operational amplifier output signal and connected to the amplifier core transistor circuit for controlling the amount of current flowing in the amplifier core transistor circuit. The digital-to-analog converter has a programmable resistance value for controlling the resistance of the digital-to-analog converter to thereby adjust a digital-to-analog converter output signal fed to the second input node of the operational amplifier for controlling an amplifier output signal at the amplifier output node.

A multi-band power amplifier module includes at least one transmission input terminal, at least one power amplifier circuit that receives a first transmission signal and a second transmission signal through the at least one transmission input terminal, a first filter circuit that allows the first transmission signal to pass therethrough, a second filter circuit that allows the second transmission signal to pass therethrough, at least one transmission output terminal through which the first and second transmission signals output from the first and second filter circuits are output, a transmission output switch that outputs each of the first and second transmission signals output from the at least one power amplifier circuit to the first filter circuit or the second filter circuit, and a first tuning circuit that adjusts impedance matching between the at least one power amplifier circuit and the at least one transmission output terminal.

Aspects of the present disclosure provide for a system. In at least some examples, the system includes an embedded Universal Serial Bus 2 (eUSB2) device having a first receiver and a first transmitter, a processor, a second transmitter coupled to the processor, a second receiver coupled to the processor, a drive low circuit coupled to the processor second transmitter, and differential signal lines having a length greater than ten inches. The differential signal lines are coupled at a first end to the first receiver and the first transmitter and at a second end to the second transmitter and the second receiver. The processor is configured to control the drive low circuit to drive the differential signal lines low with a logic 0 to cause the first receiver to receive the logic 0 and a value of a signal present on the differential signal lines to reach about 0 volts.

A configurable radio frequency system. The system includes: a plurality of radio frequency cells connected in a cascade. Each of the radio frequency cells includes an input switch connected to an input of the radio frequency system, an output switch connected to an output of the radio frequency system, and a plurality of elements, each of the elements being connected between the input switch and the output switch. The input switch and the output switch are configured, depending on their respective settings, to cause a radio frequency signal path from an input of the cell to an output of the cell to include one of the elements. The plurality of elements in each cell includes a band pass filter, an attenuator, a through path, an amplifier, and a mixer.

A radio-frequency (RF) transceiver front-end circuit includes an antenna, a power amplifier, a low-noise amplifier, a first switch unit and a second switch unit. The power amplifier is connected to a transmitting unit and the antenna to form a transmission path. The low-noise amplifier is connected to a receiving unit and the antenna to form a reception path. The transmission path and the reception path selectively do not include a /4 transmission line connected to the antenna. The RF transceiver front-end circuit has a receiving state and a transmitting state. In the receiving state, the first switch unit is controlled and causes the transmission path to have high impedance. In the transmitting state, the second switch unit is controlled and causes the reception path to have high impedance.