A power amplifier system for amplifying a radio frequency signal can have a driver transistor coupled to a radio frequency signal input. The system can also have a transformer balun with a main primary coil connected between the driver transistor and a voltage supply node of the power amplifier system, a secondary coil magnetically coupled to the main primary coil, and an additional primary coil configured to generate a feedback signal related to a signal induced in the main primary coil. A neutralization diode can be configured to use the feedback signal to reduce a gain variation resulting from variations in a voltage supplied from the voltage supply node of the power amplifier system. The neutralization diode can be connected between the additional primary coil and the driver transistor. Through envelope tracking, voltage supplied through the voltage supply node can change in relation to an envelope of the radio frequency signal.

A power amplifier arrangement (200) for amplifying an input signal to produce an output signal comprises a plurality N of amplifier sections (212, 213), a first input transmission line (221) comprising multiple segments and a first output transmission line (231) comprising multiple segments. Each amplifier section comprises one or more first transistors (T1) distributed along the first input transmission line (221) and the first output transmission line (231). Each amplifier section is configured to amplify a portion of the input signal to produce a portion of the output signal. A portion of the input signal is one of N portions of the input signal partitioned on any one or a combination of an amplitude basis and a time basis. The output signal is produced at an end of the first output transmission line (231) by building up N potions of the output signal from each amplifier section.

A dual amplifier apparatus is disclosed. The apparatus includes an energy module having a controller and a first and second power amplifier circuit coupled to the controller. The first and second power amplifier circuits are configured to receive and amplify an input signal to generate a first output signal into a load coupled to the output of the first and second power amplifier circuit. A power rating of the first amplifier circuit is different from a power rating of the second amplifier circuit. The controller is configured to select the first or the second power amplifier circuit.

A transformer-based amplifier, an operating method thereof, and devices including the same are disclosed. A millimeter wave amplifier includes a first transformer positioned on an input side of the millimeter wave amplifier, a second transformer positioned on an output side of the millimeter wave amplifier, and one or more of amplification stages positioned between the first transformer and the second transformer.

According to certain aspects, a chip includes a pad, a power amplifier, a transformer coupled between an output of the power amplifier and the pad, a transistor coupled between the transformer and a ground, and a first clamp circuit coupled between a gate of the transistor and a drain of the transistor.

An apparatus includes an amplifier and a first inductor coupled to an input of the amplifier. The apparatus also includes a second inductor that is inductively coupled to the first inductor and that couples the amplifier to a first supply node. The apparatus further includes a third inductor that is inductively coupled to the first inductor and to the second inductor and that couples the amplifier to a second supply node.

A load-insensitive power amplifier power detector that excludes the use of couplers is disclosed. The load-insensitive power amplifier power detector may include a voltage sampling circuit in electrical communication with a collector of a power amplifier and configured to sample a first voltage from the power amplifier. The load-insensitive power amplifier power detector may include a current sampling circuit in electrical communication with the collector of the power amplifier and configured to sample an output current from the power amplifier. Further, the load-insensitive power amplifier power detector may include a current-to-voltage converter connected between the voltage sampling circuit and an output of the load-insensitive power amplifier power detector. The current-to-voltage converter may be configured to convert the output current to obtain a second voltage. Moreover, a combination of the first voltage and the second voltage may form a detector voltage corresponding to an incident power of the power amplifier.

Certain aspects of the present disclosure generally relate to an amplifier configured to process signals received in different frequency bands, where at least a portion of the amplifier is shared between different modes corresponding to the different frequency bands. One example circuit generally includes an amplifier having at least one first transistor configured to amplify a first signal received in a first mode of operation (e.g., associated with a particular frequency band), and at least one second transistor configured to amplify a second signal received in a second mode of operation. The amplifier may also include a transformer comprising a primary winding and a secondary winding, and one or more switches configured to selectively couple the primary winding to the first transistor or the second transistor based on the first mode or the second mode of operation, respectively. In certain aspects, the transformer may be coupled to a transconductance circuit.

A transmission apparatus is provided with: a plurality of amplification units that amplify RF signals arranged in at least 2 bands; a first control unit that selects amplification units that perform an amplification operation, from among the plurality of amplification units, in accordance with total power of RF signals to be transmitted; a second control unit which, in accordance with a power ratio of the RF signals to be transmitted in respective bands, changes the power ratio of the RF signals in the respective bands while keeping constant the total power of the RF signals received at each of the selected amplification units; and a combining unit that combines the RF signals outputted by the selected amplification units.

Size reduction is enabled. A power amplifying circuit includes a splitter, a first amplifier, a second amplifier, and a third amplifier. The splitter splits an input signal into a first signal and a second signal. The first amplifier has a first input terminal and a first output terminal, amplifies the first signal, and outputs a first amplified signal. The second amplifier has a second input terminal and a second output terminal, amplifies the second signal, and outputs a second amplified signal. The third amplifier has a third input terminal and a third output terminal, amplifies the first signal, and outputs a third amplified signal. The first output terminal and the second output terminal are connected to each other, the third input terminal is connected to the first input terminal, and the third output terminal is connected to the second output terminal.