Disclosed herein are methods for amplifying radio-frequency signals. Methods include using pre- and post-amplifier bandpass filters to provide opposite phase shifts and to reduce out-of-band noise produced in the filtering process. Methods also include reducing the gain of amplifiers in a downstream module in response to increasing the gain of amplifiers in the receiver module. This can be done to improve linearity in the downstream module.

Disclosed herein are methods for amplifying radio-frequency signals. Methods include using pre- and post-amplifier bandpass filters to provide opposite phase shifts and to reduce out-of-band noise produced in the filtering process. Methods also include reducing the gain of amplifiers in a downstream module in response to increasing the gain of amplifiers in the receiver module. This can be done to improve linearity in the downstream module.

A power amplifier module includes a first transistor that amplifies and outputs a radio frequency signal, a second transistor smaller in size than the first transistor and connected in parallel with the first transistor, a third transistor that supplies a bias current to the first and second transistors, a current detection circuit that detects a current flowing through a collector of the second transistor, and a bias control circuit that controls the bias current supplied from the third transistor to the first and second transistors by supplying a current corresponding to a detection result of the current detection circuit to a collector or a drain of the third transistor. In a case that a current flowing through the collector of the second transistor is larger than a predetermined threshold value, the bias control circuit reduces the current supplied to the collector or the drain of the third transistor.

A variable gain amplifier circuit including a first amplifier, a second amplifier, and a variable capacitor connected in series between the first amplifier and the second amplifier is disclosed. As a gain of the variable gain amplifier circuit varies, the input impedance, output impedance, noise figure and third-order output intercept point (OIP3) of the variable gain amplifier circuit remain unchanged.

A radio frequency (RF) power combining amplifier circuit has a circuit input and a circuit output. A first amplifier is connected to the circuit input and to a first bias input. A first output matching network is connected to an output of the first amplifier and to the circuit output. A second amplifier is connected to the circuit input and to a second bias input. A second output matching network is connected to an output of the second amplifier, and to the circuit output. A voltage level of an input signal applied to the circuit input, together with the respective first bias input and the second bias input, selectively activates the first amplifier and the second amplifier.

A radio frequency (RF) power combining amplifier circuit has a circuit input and a circuit output. A first amplifier is connected to the circuit input and to a first bias input. A first output matching network is connected to an output of the first amplifier and to the circuit output. A second amplifier is connected to the circuit input and to a second bias input. A second output matching network is connected to an output of the second amplifier, and to the circuit output. A voltage level of an input signal applied to the circuit input, together with the respective first bias input and the second bias input, selectively activates the first amplifier and the second amplifier.

A radio-frequency device comprises a first radio-frequency signal node, a second radio-frequency signal node, a first power cell path coupled between the first radio-frequency signal node and a ground reference node, the first power cell path including a first transistor having an input terminal coupled to the second radio-frequency signal node, and a second power cell path coupled in parallel with the first power cell path between the first radio-frequency signal node and the ground reference node, the second power cell path including a second transistor having an input terminal coupled to the second radio-frequency signal node and an output terminal that is electrically isolated from an output terminal of the first transistor.

A radio-frequency device comprises a first radio-frequency signal node, a second radio-frequency signal node, a first power cell path coupled between the first radio-frequency signal node and a ground reference node, the first power cell path including a first transistor having an input terminal coupled to the second radio-frequency signal node, and a second power cell path coupled in parallel with the first power cell path between the first radio-frequency signal node and the ground reference node, the second power cell path including a second transistor having an input terminal coupled to the second radio-frequency signal node and an output terminal that is electrically isolated from an output terminal of the first transistor.

A power amplifier module includes an output-stage amplifier, a driver-stage amplifier, an input switch, an output switch, an input matching circuit, an inter-stage matching circuit, an output matching circuit, and a control circuit. The input switch selectively connects one of a plurality of input signal paths to an input terminal of the driver-stage amplifier. The output switch selectively connects one of a plurality of output signal paths to an output terminal of the output-stage amplifier. The control circuit controls operations of the driver-stage amplifier and the output-stage amplifier. The input switch, the output switch, and the control circuit are integrated into an IC chip. The control circuit is disposed between the input switch and the output switch.

In one embodiment, an RF power amplifier includes a first transistor and a second transistor in parallel, wherein a gate of the first transistor and a gate of the second transistor are configured to be driven by an RF source. A third transistor comprising a drain is operably coupled to both a source of the first transistor and a source of the second transistor. A control circuit is operably coupled to a gate of the third transistor and configured to alter a gate-to-source voltage of the third transistor, thereby altering a drain current of each of the first transistor and the second transistor, thereby altering an output power of the RF power amplifier.