A class-F power amplifier (PA) with a matching network is disclosed herein. The class-F PA comprises a first switch and a second switch operating in differential mode, with a second harmonic trap circuitry selectively terminating the drain terminals to ground at a second harmonic frequency. The second harmonic trap circuitry comprises a plurality of lumped inductive and capacitive components. The PA further comprises a common mode trap and a matching network to reduce the imbalance of the drain terminal impedance between first harmonics and third harmonics.

A chopper amplifier and method of operation are described. The chopper amplifier comprises a first chopper arranged to modulate an input signal using a first chopper signal having a chopper frequency. An amplification stage has an input arranged to receive the chopped signal and an output, and supplies an amplified signal at the output. An output chopper is arranged to integrate the amplified signal using a second chopper signal having the chopper frequency to generate an amplified output signal. The amplification stage is further configured to filter the chopped signal to attenuate signal components having frequencies lower than the chopper frequency.

An interface for inter-chip communication, comprises a transmitter part (TX) for transmitting a differential signal and a receiver part (RX) for receiving the differential signal, the transmitter part (TX) being provided in a first integrated circuit chip (CHIP A) and the receiver part (RX) being provided in a second integrated circuit chip (CHIP B). The transmitter part (TX) comprises a first transistor (Tx1) and a second transistor (Tx2) arranged in a common source configuration, and the receiver part (RX) comprises a third transistor (TR1) and a fourth transistor (TR2) arranged in a common gate configuration. Current flowing in the receiver part (RX) also flows through the transmitter part (TX).

An envelope tracking amplifier having stacked transistors is presented. The envelope tracking amplifier uses dynamic bias voltages at one or more gates of the stacked transistors in addition to a dynamic bias voltage at a drain of a transistor.

Control systems and methods for power amplifiers operating in envelope tracking mode are presented. A set of corresponding functions and modules are described and various possible system configurations using such functions and modules are presented.

An envelope tracking amplifier having stacked transistors is presented. The envelope tracking amplifier uses dynamic bias voltages at one or more gates of the stacked transistors in addition to a dynamic bias voltage at a drain of a transistor.

An interface for inter-chip communication, comprises a transmitter part (TX) for transmitting a differential signal and a receiver part (RX) for receiving the differential signal, the transmitter part (TX) being provided in a first integrated circuit chip (CHIP A) and the receiver part (RX) being provided in a second integrated circuit chip (CHIP B). The transmitter part (TX) comprises a first transistor (Tx1) and a second transistor (Tx2) arranged in a common source configuration, and the receiver part (RX) comprises a third transistor (TR1) and a fourth transistor (TR2) arranged in a common gate configuration. Current flowing in the receiver part (RX) also flows through the transmitter part (TX).

Various envelope tracking amplifiers are presented that can be switched between an ET (envelope tracking) mode and a non-ET mode. Switches and/or tunable components are utilized in constructing the envelope tracking amplifiers that can be switched between the ET mode and the non-ET mode.

A method of increasing a current flowing through an inductor includes receiving an input signal with a driver stage, the driver stage including the inductor coupled in series with a loading between an output node of the driver stage and a power line. In response to a transition in the input signal from a first voltage state to a second voltage state, a first current flowing through the loading and the inductor is increased. During the transition in the input signal, the current flowing through the inductor is increased by increasing a second current in a circuitry though a node between the inductor and the loading.

Various envelope tracking amplifiers are presented that can be switched between an ET (envelope tracking) mode and a non-ET mode. Switches and/or tunable components are utilized in constructing the envelope tracking amplifiers that can be switched between the ET mode and the non-ET mode.