A scalable periphery tunable matching power amplifier is presented. Varying power levels can be accommodated by selectively activating or deactivating unit cells of which the scalable periphery tunable matching power amplifier is comprised. Tunable matching allows individual unit cells to see a constant output impedance, reducing need for transforming a low impedance up to a system impedance and attendant power loss. The scalable periphery tunable matching power amplifier can also be tuned for different operating conditions such as different frequencies of operation or different modes.

A power amplifier system is disclosed having a first amplifier with a high-power input and a high-power output. A second amplifier has a low-power input and a low-power output. A reconfigurable mode switch network has a first series switch branch coupled between the high-power output and an RF output, a first shunt branch is coupled between the RF output and a fixed voltage node, and a second series switch branch is coupled between the low-power output and a shared node of the first shunt branch. The shared node separates the first shunt branch into a first shared section that is between the RF output and the shared node and a second shared section that is between the shared node and the fixed voltage node.

Apparatus and methods for a no-load-modulation power amplifier are described. No-load-modulation power amplifiers can comprise multiple amplifiers connected in parallel to amplify a signal that has been divided into parallel circuit branches. One of the amplifiers can operate as a main amplifier in a first amplification class and the remaining amplifiers can operate as peaking amplifiers in a second amplification class. The main amplifier can see essentially no modulation of its load between the power amplifier's fully-on and fully backed-off states. The power amplifiers can operate in symmetric and asymmetric modes. Improvements in bandwidth and drain efficiency over conventional Doherty amplifiers are obtained. Further improvements can be obtained by combining signals from the amplifiers with hybrid couplers.

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.

An H-bridge power amplifier arrangement with envelope tracking is disclosed. The power amplifier arrangement comprises four elements form the four corner bars of a first H-bridge structure with a load formed as the cross bar of the first H-bridge structure. The power amplifier arrangement further comprises a rectifier circuit coupled between the first positive power supply and the third positive power supply configured to recycle the sinking envelope current.

This application relates to Class D amplifier circuits. A modulator controls a Class D output stage based on a modulator input signal (Dm) to generate an output signal (Vout) which is representative of an input signal (Din). An error block, which may comprise an ADC, generates an error signal (ε) from the output signal and the input signal. In various embodiments the extent to which the error signal (ε) contributes to the modulator input signal (Dm) is variable based on an indication of the amplitude of the input signal (Din). The error signal may be received at a first input of a signal selector block. The input signal may be received at a second input of the signal selector block. The signal selector block may be operable in first and second modes of operation, wherein in the first mode the modulator input signal is based at least in part on the error signal; and in the second mode the modulator input signal is based on the digital input signal and is independent of the error signal. The error signal can be used to reduce distortion at high signal levels but is not used at low signal levels and so the noise floor at low signal levels does not depend on the component of the error block.

A supply modulator is provided, having a first amplifier circuit configured to generate a first electrical signal, a second amplifier circuit configured to generate a second electrical signal, the first and second electrical signals being for driving an electrical load, and a control circuit electrically coupled to the first and second amplifier circuits wherein the control circuit is configured to generate a pulsed electrical signal and to supply an output control signal to the second amplifier circuit for controlling generation of the second electrical output signal, wherein the supply modulator is configured to operate in two modes of operation, for the first amplifier circuit to generate the first electrical signals in response to quiescent current of the first amplifier circuit, for the control circuit to generate a modulated electrical signal in accordance with a clock signal in one mode, and, for the second amplifier circuit to operate.

The present invention provides a voltage regulator including a voltage control circuit and a current control circuit. The voltage control circuit is configured to receive an output voltage of the voltage regulator to generate a first current to an output terminal of the voltage regulator; and the current control circuit is configured to generate a second current to the output terminal of the voltage regulator according to an output current of the voltage regulator, wherein the output current is generated according to the first current and the second current.

Disclosed is a power amplifier system having a main amplifier with an input coupled to a main radio frequency (RF) input and an output connected to a main RF output, wherein the main amplifier exhibits a nonlinear gain characteristic with compression. At least one compression compensating amplifier has a signal input coupled to the common RF input and a signal output coupled to the common RF output.

Methods and apparatus for a signal isolator that mitigates the effects of CMTI strikes. In embodiments, a first die comprises a transmit module and the first die has a first voltage domain; and a second die comprises a receive module including a receive amplifier configured to receive from the transmit module a transmit signal that includes a differential signal and a common mode current. The second die may have a second voltage domain with the first and second die being separated by an isolation barrier. In embodiment, the receive amplifier includes a differential amplifier to receive the differential input signal from the transmit module; and a common mode module configured to sense the common mode current and sink or source the common mode current and minimize changes to an input impedance of the receive amplifier.