Front end systems and related devices, integrated circuits, modules, and methods are disclosed. One such packaged module includes a low noise amplifier in an interior of a radio frequency shielding structure and an antenna external to the radio frequency shielding structure. The low noise amplifier includes a first inductor, an amplification circuit, and a second inductor magnetically coupled to the first inductor to provide negative feedback to linearize the low noise amplifier. The radio frequency shielding structure can extend above a package substrate. The antenna can be on the package substrate. Other embodiments of front end systems are disclosed, along with related devices, integrated circuits, modules, methods, and components thereof.

In certain aspects, an apparatus includes a transformer including an input inductor and an output inductor, wherein the input inductor is magnetically coupled to the output inductor. The apparatus also includes a transconductance driver configured to drive the input inductor based on an input signal. The apparatus further includes a feedback circuit configured to detect an output voltage swing at the output inductor, generate a regulated voltage at the input inductor, and control the regulated voltage based on the detected output voltage swing.

A low noise amplifier includes at least two variable gain amplifier stages, each variable gain amplifier configured to accept an input signal and to provide a load driving signal; a tunable bandpass filter connected as a load to each variable gain amplifier stage, wherein each bandpass filter includes a resonant tank, each resonant tank including an inductor, wherein each inductor of each resonant tank is oriented in orthogonal relation with respect to each respective longitudinal axis of each next inductor, the orthogonal relation of the respective longitudinal axes configured to reduce mutual coupling between the tunable bandpass filters; a cross-coupled transistor pair, and at least one cross-coupled compensation transistor pair biased in a subthreshold region configured to add a transconductance component as a function of a load driving signal; and, a controller circuit configured to tune each tunable bandpass filter.

The present invention generally relates to a structure and method of audio amplifier with power feedback, including a power amplifying unit, a loud-speaker, a current sensing unit, a voltage sensing unit and a multiplying unit, the power amplifying unit includes an input side and an output side, the input side inputs an audio voltage signal; and the loud-speaker is electrically connected to an output side of the power amplifying unit; the current sensing unit is electrically connected to the output side of the power amplifying unit and senses the output current of the power amplifying unit and then converted into a current control voltage signal; the voltage sensing unit is electrically connected to the output side of the power amplifying unit, and senses the output voltage of the power amplifying unit to form an output sensing voltage signal; the multiplying unit obtains the voltage of the current control voltage multiplied by the output sensing voltage, and the output side of the multiplying unit is electrically connected to the input side of the power amplifying unit to form a closed loop power feedback structure, accordingly improving the output quality of the amplifier and loud-speaker.

Front end systems and related devices, integrated circuits, modules, and methods are disclosed. One such front end system includes a low noise amplifier in a receive path and a multi-mode power amplifier circuit in a transmit path. An overload protection circuit can adjust an impedance of a switch coupled to the low noise amplifier based on a signal level of the low noise amplifier. The multi-mode power amplifier circuit includes a stacked output stage including a transistor stack of two or more transistors. The multi-mode power amplifier circuit also includes a bias circuit configured to control a bias of at least one transistor of the transistor stack based on a mode of the multi-mode power amplifier circuit. Other embodiments of front end systems are disclosed, along with related devices, integrated circuits, modules, methods, and components thereof.

Front end systems and related devices, integrated circuits, modules, and methods are disclosed. One such packaged module includes a multi-mode power amplifier circuit in an interior of a radio frequency shielding structure and an antenna external to the radio frequency shielding structure. The multi-mode power amplifier circuit includes a stacked output stage including a transistor stack of two or more transistors. The multi-mode power amplifier circuit also includes a bias circuit configured to control a bias of at least one transistor of the transistor stack based on a mode of the multi-mode power amplifier circuit. The radio frequency shielding structure can extend above a package substrate. The antenna can be on the package substrate. Other embodiments of front end systems are disclosed, along with related devices, integrated circuits, modules, methods, and components thereof.

Aspects of this disclosure relate to an impedance transformation circuit for use in an amplifier, such as a low noise amplifier. The impedance transformation circuit includes a matching circuit including a first inductor. The impedance transformation circuit also includes a second inductor. The first and second inductors are magnetically coupled to each other to provide negative feedback to linearize the amplifier.

Front end systems and related devices, integrated circuits, modules, and methods are disclosed. One such packaged module includes a multi-mode power amplifier circuit in an interior of a radio frequency shielding structure and an antenna external to the radio frequency shielding structure. The multi-mode power amplifier circuit includes a stacked output stage including a transistor stack of two or more transistors. The multi-mode power amplifier circuit also includes a bias circuit configured to control a bias of at least one transistor of the transistor stack based on a mode of the multi-mode power amplifier circuit. The radio frequency shielding structure can extend above a package substrate. The antenna can be on the package substrate. Other embodiments of front end systems are disclosed, along with related devices, integrated circuits, modules, methods, and components thereof.

An amplifier, comprising: an amplifying element having an input side and an output side; a first transformer on the output side of the amplifying element arranged to mutually couple a fraction of the output current from the amplifying element onto the input side of the amplifying element; a second transformer on the input side of the amplifying element arranged to increase the input voltage on the input side via mutual coupling of its primary and secondary windings; wherein a primary winding of the first transformer is connected to an output of the amplifying element; wherein a secondary winding of the first transformer is ac connected to a secondary winding of the second transformer; and wherein the primary winding of the first transformer is dc blocked from the secondary winding of the second transformer. The negative and the positive reactive feedback loops are not formed from the same trifilar transformer.

Aspects of this disclosure relate to an impedance transformation circuit for use in an amplifier, such as a low noise amplifier. The impedance transformation circuit includes a matching circuit including a first inductor. The impedance transformation circuit also includes a second inductor. The first and second inductors are magnetically coupled to each other to provide negative feedback to linearize the amplifier.