Sequoia Communications Corporation

Psemi Corporation

Other

Nxp B.v.

Nokia Mobile Phones Limited

Conexant Systems, Inc.

Peregrine Semiconductor Corporation

Quintic Holdings

Damian Costa

John B Groe

Tero Tapio Ranta

Chih-Chieh Cheng

Michael Naone Farias

Christopher C Murphy

Mats Lindstrom

Joseph Jay Austin

Babak Nejati

Jianhua Lu

Weinan Gao

William Huff

Mark Santini

Naone Farias

Richard Bryon Whatley

Robert N Ruth, Jr

Kendal McNaught-Davis Hess

Shahram Mahdavi

Roy Enright

Daniel Firoiu

Weinen Gao

Joe Austin

A power detector with wide dynamic range. The power detector includes a linear detector, followed by a voltage-to-current-to-voltage converter, which is then followed by an amplification stage. The current-to-voltage conversion in the converter is performed logarithmically. The power detector generates a desired linear-in-dB response at the output. In this power detector, the distribution of gain along the signal path is optimized in order to preserve linearity, and to minimize the impact of offset voltage inherently present in electronic blocks, which would corrupt the output voltage. Further, the topologies in the sub-blocks are designed to provide wide dynamic range, and to mitigate error sources. Moreover, the temperature sensitivity is designed out by either minimizing temperature variation of an individual block such as the v-i-v detector, or using two sub-blocks in tandem to provide overall temperature compensation. In one aspect, active resistors are used in order to compensate for temperature variations.

Power detector with wide dynamic range

Methods and devices for providing a feedback network in a multi-stage power amplifier are described. According to one aspect, a final amplifier of the multi-stage power amplifier is a cascode amplifier. The feedback network is placed between an output of the final amplifier and an output of a driver amplifier. The feedback network can decrease a mismatch between the output impedance of the final amplifier and a load presented to the final amplifier. In addition, the feedback network can change a load presented to the driver amplifier and thereby allow the transfer functions of each stage to be tuned so that the overall transfer function of the multi-stage amplifier becomes more linear.

Multi-stage stacked power amplifier feedback circuit for improved performance

Methods and devices for improving AM-AM and AM-PM performance of an RF amplifier are presented. According to one aspect, input and output harmonic terminations coupled to the input and output of the amplifier are tuned at frequencies near to, but different than, a second harmonic frequency of an RF signal to be amplified. Improved AM-AM and AM-PM performance is obtained when i) the input harmonic termination is tuned at a frequency that is below the second harmonic frequency and the output harmonic termination is tuned at a frequency that is above the second harmonic frequency, and ii) the input harmonic termination is tuned at a frequency that is farther away from the second harmonic frequency than the frequency used for tuning of the output harmonic termination.

Second harmonic terminations for AM-AM and AM-PM suppression

A method and circuit for significantly reducing the switching transients of a digital step attenuator (DSA) by employing a segmented architecture that combines thermometer and binary coded stages. This approach reduces the number of attenuator stages switching at the same time and thus minimizes any glitch amplitude. Embodiments of a segmented DSA may be realized with 'pi' and 'bridged-T' attenuators, as well as with simple tuned L-pad attenuators combined in a resistor ladder network.

Segmented attenuator with glitch reduction

Radio-frequency (RF) circuits, methods and systems are implemented according to a variety of embodiments. According to one such embodiment, a radio-frequency (RF) receiver circuit is implemented with an adjustable RF filter circuit in a receive path of the RF receiver circuit. A local oscillator (LO) generates a LO signal and an RX_LO signal from the LO signal. A mixing circuit mixes a signal received from the adjustable RF filter circuit and the RX_LO signal. An intermediate-frequency (IF) circuit generates an IF_cal signal at the receiver circuit. A calibration circuit implements both a calibration mode and a receive mode. In the calibration mode, a calibration signal is injected into the receive path. A setting of the adjustable RF filter circuit is determined. In the receive mode, the calibration circuit disables the injection of the calibration signal into the receive path of the RF receiver circuit.

RF filter with low-IF mixing, tuning and calibration

Systems for multi-mode phase modulation are disclosed. Systems provide for direct modulation of a multi-mode voltage controlled oscillator (VCO). A fractional-N counter may be used in a phase-locked loop (PLL) to synthesize a radio frequency carrier signal. The multi-mode VCO may be characterized by a first frequency gain during operation in a first mode and by a second frequency gain during operation in a second mode where signals controlling the first and second operating modes are provided by a control circuit. The control circuit may include a switch to provide control signals to the VCO.

Multi-mode VCO for direct FM systems

Systems for suppressing image noise are provided. In this regard, one embodiment includes a system for suppressing image noise comprising a low noise amplifier (LNA) configured to amplify a received RF signal, an RF variable gain attenuator with an image rejection filter with programmable bandwidth configured to suppress image noise and image interference, and an RF mixer configured to perform frequency translation.

Systems and methods for reducing broadband image noise through a programmable bandwidth RF variable gain attenuator

Multi-segment gain control system. Apparatus is provided for a multi-segment gain control. The apparatus includes logic to convert a gain control signal to an exponential signal, and logic to map the exponential signal to multiple control signals that are used to control multiple gain stages to produce linear multi-segment gain control.

Multi-segment gain control system

Direct down-conversion mixer. A direct down-conversion mixer is provided. The mixer comprises an LO switching pair coupled to receive an RF input signal and produce a down converted output signal. The mixer also comprises an integrator coupled to receive the output signal and produce an integrator output signal. The mixer also comprises a control circuit coupled to receive an input voltage and the integrator output signal to produce a control signal that is coupled to the LO switching pair.

Direct down-conversion mixer architecture

Systems involving temperature compensation of voltage controlled oscillators are provided. In this regard, a representative system incorporates: a voltage controlled oscillator (VCO) having a tuning port and a phase-locked loop (PLL); and a temperature dependent voltage source. The VCO selectively exhibits one of a coarse tuning mode in which the temperature dependent voltage source is electrically connected to the VCO tuning port, and a locked mode in which the temperature dependent voltage source is not electrically connected to the VCO tuning port such that the PLL controls the frequency of the VCO.

Systems involving temperature compensation of voltage controlled oscillators

Continuous variable-gain low-noise amplifier. The amplifier continuously adjusts its gain between well-defined high and low values by using a cascode current-steering circuit to partition signal current between two different nodes of an output loading network. A shunt feedback network connected from an intermediate node of the loading network to the input provides negative feedback that linearizes the amplifier as its gain is decreased. The circuit degrades the noise figure at lower gains by varying the gain without directly dumping the signal current to the power supply. The circuit produces only small changes in input and output impedances and preserves an improved reverse-isolation cascode characteristic as the gain is controlled.

Continuous variable-gain low-noise amplifier

A bias voltage circuit with ultra low output impedance. The circuit incorporates feedback to reduce the output impedance at both low and RF frequencies. The bias circuit outputs a bias signal for biasing an amplifier. The bias circuit includes an input stage that receives an input signal and produces the bias signal at an output terminal that is coupled to a gain stage. The bias circuit also includes a load coupled to the input stage at a first terminal, and a feedback circuit coupled between the first terminal and the gain stage.

Bias voltage circuit with ultra low output impedance

Continuous variable-gain low-noise amplifier. The amplifier continuously adjusts its gain between well-defined high and low values by using a cascode current-steering circuit to partition signal current between two different nodes of an output loading network. A shunt feedback network connected from an intermediate node of the loading network to the input provides negative feedback that linearizes the amplifier as its gain is decreased. The circuit degrades the noise figure at lower gains considerably less than conventional circuits by varying the gain without directly dumping the signal current to the power supply. The circuit produces only small changes in input and output impedances and preserves an improved reverse-isolation cascode characteristic as the gain is controlled.

A variable-gain BiCMOS transconductance amplifier (VGA). An NMOS differential pair amplifier with bipolar cascoding provides continuous gain control by adjustment of drain-source voltage to shift the NMOS differential pair from a saturation region operation and high gain to a triode operation and low gain. A simple control circuit is used in order to generate the desired exponential gain to linear control voltage characteristic that is stable over temperature and process. The shift from saturation to triode operation of the input NMOS differential pair simultaneously increases the input linearity as the gain is reduced.

Growing community of inventors

San Diego, CA, United States of America

Damian Costa