Marvell International Limited

Donghong Cui

Yonghua Song

King Chun Tsai

Yungping Hsu

George Chien

Randy Tsang

Sai-Wang Tam

Alden C Wong

Hsiao-Cheng Tang

Ovidiu Carnu

Wai Lau

Timothy Loo

Amir Ghaffari

Radio-frequency front-end circuitry includes an output terminal, a receive amplifier controllably coupled to the output terminal, at least one transmit amplifier controllably inductively coupled to the output terminal, and at least one impedance element controllably coupled between ground and one of the at least one transmit amplifier to reduce degradation of output of the radio-frequency front-end circuitry when the at least one transmit amplifier is not in use. In differential signaling, there is an impedance element between ground and each pole of the differential signal. A second transmit amplifier may generate second transmit signals and harmonics of the second transmit signals, and the second transmit amplifier may be switchably connected to the output of a first transmit amplifier so that output of the second transmit amplifier is filtered by the one of the first transmit amplifier. The transmit amplifiers may include a WiFi power amplifier and a BLUETOOTH&#xae; power amplifier.

Radio-frequency front end with power amplifier detuning to reduce output degradation

An electrical circuit includes an amplifier. The amplifier includes an input circuit in communication with an input of the amplifier. A start-up circuit is in communication with the input circuit. The start-up circuit is configured to generate a start-up signal to enable subsequent operation of the amplifier. The start-up circuit turns off when an output of the amplifier reaches a threshold voltage. An output circuit is in communication with each of the outputs of the amplifier, the input circuit, and the start-up circuit.

Baseband filter start-up circuit

An electrical circuit comprises a plurality of amplifiers. Each of the plurality of amplifiers comprises an input circuit in communication with an input of the amplifier and a start-up circuit in communication with the input circuit. The start-up circuit is configured to generate a start-up signal to enable subsequent operation of the amplifier. An output circuit communicates with an output of the amplifier and with the input circuit and the start-up circuit. Respective inputs of a first and a second amplifier of the plurality of amplifiers are in communication with outputs of a third amplifier of the plurality of amplifiers. Outputs of the second amplifier are in communication with inputs of the third amplifier.

An amplifier comprises an input circuit that receives an input to the amplifier. A start-up circuit communicates with the input circuit, generates a start-up signal, and turns off the start-up signal when an output of the amplifier reaches a threshold voltage. The start-up circuit includes a first transistor having first and second terminals and a base terminal and a second transistor having first and second terminals and a base terminal. The base terminals of the first and second transistors receive a bias input, the first terminals of the first and second transistors communicate with each other and with a first current source, and the second terminals of the first and second transistors communicate with the input circuit.

Apparatus, systems, and methods implementing techniques for reducing the variation of a DC offset are described. An input signal is amplified to produce an intermediate signal. The intermediate signal is processed to produce a feedback signal and an output signal, where the output signal has a DC offset that varies with a varying parameter of the circuitry used to process the intermediate signal. Variation of the DC offset of the output signal is reduced using the feedback signal. In one implementation, the circuitry used to process the intermediate signal is a variable-gain amplifier circuit, and the DC offset of the output signal varies with a gain of the variable-gain amplifier.

Amplifier calibration

An electrical circuit includes an amplifier. The amplifier includes an input circuit in communication with an input of the amplifier. The amplifier includes a start-up circuit in communication with the input circuit. The start-up circuit is configured to generate a start-up signal to enable subsequent operation of the amplifier. Generation of the start-up signal by the start-up circuit can be ceased when the operation of the amplifier reaches a steady-state. The amplifier also includes an output circuit in communication with an output of the amplifier and in communication with the input circuit and the start-up circuit.

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Donghong Cui