Provided is a power amplification circuit that includes: an amplifier that amplifies an input signal and outputs an amplified signal; a first bias circuit that supplies a first bias current or voltage to the amplifier; a second bias circuit that supplies a second bias current or voltage to the amplifier; a first control circuit that controls the first bias current or voltage; and a second control circuit that controls the second bias current or voltage. The current supplying capacity of the first bias circuit is different from the current supplying capacity of the second bias circuit.

Provided is a power amplification circuit that includes: an amplifier that amplifies an input signal and outputs an amplified signal; a first bias circuit that supplies a first bias current or voltage to the amplifier; a second bias circuit that supplies a second bias current or voltage to the amplifier; a first control circuit that controls the first bias current or voltage; and a second control circuit that controls the second bias current or voltage. The current supplying capacity of the first bias circuit is different from the current supplying capacity of the second bias circuit.

Systems, devices and methods related to multi-band power amplifier. In some embodiments, a power amplifier module includes a power amplifier having an output stage and configured to receive a signal. The power amplifier module also includes a first programmable harmonic termination circuit in electrical communication with the output stage of the power amplifier. The first programmable harmonic termination circuit includes a first plurality of capacitors and a first plurality of switches, with at least one of the first plurality of capacitors being in electrical communication with at least one of the first plurality of switches. The power amplifier module further includes a controller configured to modify a configuration of the first plurality of switches of the first programmable harmonic termination circuit based at least in part on a second harmonic frequency of the signal.

Systems, devices and methods related to multi-band power amplifier. In some embodiments, a power amplifier module includes a power amplifier having an output stage and configured to receive a signal. The power amplifier module also includes a first programmable harmonic termination circuit in electrical communication with the output stage of the power amplifier. The first programmable harmonic termination circuit includes a first plurality of capacitors and a first plurality of switches, with at least one of the first plurality of capacitors being in electrical communication with at least one of the first plurality of switches. The power amplifier module further includes a controller configured to modify a configuration of the first plurality of switches of the first programmable harmonic termination circuit based at least in part on a second harmonic frequency of the signal.

In one embodiment, an impedance matching network includes an electronically variable reactance element (EVRE) comprising discrete reactance elements and corresponding switches. The switches are configured to switch in and out the discrete reactance elements to alter a total reactance provided by the EVRE. A monitoring circuit is operably coupled to the EVRE. For each discrete reactance element, the monitoring circuit monitors a value related to the discrete reactance element or its corresponding switch. Upon determining the monitored value exceeds a predetermined amount, the monitoring circuit the discrete reactance element of the EVRE from switching in or out.

A power amplifier circuit includes an amplifier transistor that amplifies an input signal, a resistance element coupled in series with the base of the amplifier transistor, a bias transistor that supplies a bias current from the emitter or the source of the bias transistor to the base of the amplifier transistor through the resistance element, and a feedback circuit that changes a base or gate voltage of the bias transistor to follow a change in the bias current supplied to the base of the amplifier transistor.

A bias circuit includes a current source to generate a reference current, a temperature compensation portion in an off-state in an initial start period in response to a first control signal, and in an on-state in a normal driving period, subsequent to the initial start period, and to receive a first current of the reference current, and a bias output portion to generate a warm up current based on the reference current in the initial start period and to generate a bias current based on a second current, which is lower than the reference current by an amount of the first current, in the normal driving period.

Disclosed herein are configurations and devices for amplifying radio-frequency signals. The devices and configurations include using a wide-band or tunable downstream amplifier to amplify signals in a downstream or back-end module. The signals are first filtered and amplified by an upstream or front-end module that receives a diversity signal from a diversity antenna.

Disclosed herein are configurations and devices for amplifying radio-frequency signals. The devices and configurations include using a wide-band or tunable downstream amplifier to amplify signals in a downstream or back-end module. The signals are first filtered and amplified by an upstream or front-end module that receives a diversity signal from a diversity antenna.

In some embodiments, a wireless local area network (WLAN) front-end can be implemented on a semiconductor die having a semiconductor substrate, and a power amplifier implemented on the semiconductor substrate and configured for WLAN transmit operation associated with a frequency range. The semiconductor die can further include a low-noise amplifier (LNA) implemented on the semiconductor substrate and configured for WLAN receive operation associated with the frequency range. The semiconductor die can further include a transmit/receive switch implemented on the semiconductor substrate and configured to support the transmit and receive operations.