An electronic device includes a power amplifier that sets the power of a transmit signal that is transmitted via an antenna of the device, and further includes a VSWR detector to identify the VSWR at a signal path between the antenna and the power amplifier. As a person (e.g., a user) moves in close proximity to the antenna, the amount of reflected energy along the signal path increases, thereby increasing the VSWR. A power controller of the electronic device sets a gain of the power amplifier based on the VSWR to ensure that the SAR exposure to the person is maintained below a specified threshold.

Systems, methods, and apparatuses for improving reliability and/or reducing or preventing breakdown of an amplifier, specifically breakdown of a transistor of an amplifier, are disclosed. A protection circuit can be electrically coupled to the amplifier, and can be configured to reduce a voltage swing at the amplifier. The amplifier can include a first transistor, and the protection circuit can include a second transistor electrically coupled to a control terminal of the first transistor of the amplifier. When a power at a control terminal of the second transistor of the protection circuit satisfies a threshold power, the protection circuit can be configured to reduce a power at a power terminal of the first transistor the amplifier. By reducing the voltage at the power terminal of the first transistor the amplifier, the protection circuit can allow the amplifier to operate safely, without breakdown.

Embodiments provide an amplification circuit, an apparatus for amplifying, a low noise amplifier, a radio receiver, a mobile terminal, a base station, and a method for amplifying. An amplification circuit for amplifying a radio signal comprises a first amplification stage configured to amplify an input signal, V.sub.in(t), to obtain an intermediate signal. The amplification circuit further comprises a cascoding circuit configured to amplify the intermediate signal to obtain a first output signal V.sub.outn(t). The amplification circuit further comprises a second amplification stage configured to amplify the intermediate signal to obtain a second output signal, V.sub.outp(t).

Embodiments provide an amplification circuit, an apparatus for amplifying, a low noise amplifier, a radio receiver, a mobile terminal, a base station, and a method for amplifying. An amplification circuit for amplifying a radio signal comprises a first amplification stage configured to amplify an input signal, V.sub.in(t), to obtain an intermediate signal. The amplification circuit further comprises a cascoding circuit configured to amplify the intermediate signal to obtain a first output signal V.sub.outn(t). The amplification circuit further comprises a second amplification stage configured to amplify the intermediate signal to obtain a second output signal, V.sub.outp(t).

A source follower with an input node and an output node includes a first transistor, a second transistor, and a DC (Direct Current) tracking circuit. The first transistor has a control terminal, a first terminal coupled to a first node, and a second terminal coupled to a second node. The second transistor has a control terminal, a first terminal coupled to a ground voltage, and a second terminal coupled to the first node. The DC tracking circuit sets the second DC voltage at the second node to a specific level. The specific level is determined according to the first DC voltage at the first node. The output node of the source follower is coupled to the first node.

A source follower with an input node and an output node includes a first transistor, a second transistor, and a DC (Direct Current) tracking circuit. The first transistor has a control terminal, a first terminal coupled to a first node, and a second terminal coupled to a second node. The second transistor has a control terminal, a first terminal coupled to a ground voltage, and a second terminal coupled to the first node. The DC tracking circuit sets the second DC voltage at the second node to a specific level. The specific level is determined according to the first DC voltage at the first node. The output node of the source follower is coupled to the first node.

Embodiments of an apparatus that includes a substrate and an inductor residing in the substrate are disclosed. In one embodiment, the inductor is formed as a conductive path that extends from a first terminal to a second terminal. The conductive path has a shape corresponding to a two-dimensional (2D) lobe laid over a three-dimensional (3D) volume. Since the shape of the conductive path corresponds to the 2D lobe laid over a 3D volume, the magnetic field generated by the inductor has magnetic field lines that are predominately destructive outside the inductor and magnetic field lines that are predominately constructive inside the inductor. In this manner, the inductor can maintain a high quality (Q) factor while being placed close to other components.

Embodiments of an apparatus that includes a substrate and an inductor residing in the substrate are disclosed. In one embodiment, the inductor is formed as a conductive path that extends from a first terminal to a second terminal. The conductive path has a shape corresponding to a two-dimensional (2D) lobe laid over a three-dimensional (3D) volume. Since the shape of the conductive path corresponds to the 2D lobe laid over a 3D volume, the magnetic field generated by the inductor has magnetic field lines that are predominately destructive outside the inductor and magnetic field lines that are predominately constructive inside the inductor. In this manner, the inductor can maintain a high quality (Q) factor while being placed close to other components.

A bias circuit provides additional bias current for power amplifiers during data bursts to compensate for the gain droop caused by a rise in the power amplifier temperature during the data burst. A bias circuit includes a difference amplifier and switches coupled to the difference amplifier. The switches operate the bias circuit in a first mode when a transmit data burst is detected and operate the bias circuit in a second mode after the bias circuit has operated in the first mode for a predetermined period of time. In the first mode, the bias circuit charges a storage capacitor and sets an output current to zero. In the second mode, the bias circuit outputs the output current that increases above the initial value of zero as the PA warms up, where the excursion of this increase of current is determined by a register. The switches disable the bias circuit when the transmit data burst ends.

A bias circuit provides additional bias current for power amplifiers during data bursts to compensate for the gain droop caused by a rise in the power amplifier temperature during the data burst. A bias circuit includes a difference amplifier and switches coupled to the difference amplifier. The switches operate the bias circuit in a first mode when a transmit data burst is detected and operate the bias circuit in a second mode after the bias circuit has operated in the first mode for a predetermined period of time. In the first mode, the bias circuit charges a storage capacitor and sets an output current to zero. In the second mode, the bias circuit outputs the output current that increases above the initial value of zero as the PA warms up, where the excursion of this increase of current is determined by a register. The switches disable the bias circuit when the transmit data burst ends.