Qualcomm Incorporated

Marco Cassia

Aristotele Hadjichristos

Gurkanwal Singh Sahota

Aleksandar Miodrag Tasic

Xiangdong Zhang

Jose Cabanillas

Wenjun Su

Ryan Scott Castro Spring

Yan Kit Gary Hau

Robert Wilson

Kanan Gandhi

Nathan M Pletcher

Vladimir Aparin

Chiewcharn Narathong

Jeremy Darren Dunworth

Yiwu Tang

Babak Nejati

Christian Holenstein

Puay Hoe See

Joonhoi Hur

Paul J Draxler

Thomas Myers

Sang-Oh Lee

Mahim Ranjan

Yu Zhao

Guy Klemens

Calogero Davide Presti

Norman L Frederick, Jr

Aristotle Hadjichristos

Conor Donovan

Norman L Frederick

Aparin Vladimir

Thomas A Myers

An apparatus is disclosed for waveform-tailored average power tracking. In an example aspect, the apparatus includes an amplifier, a power converter, and an average power tracking module. The amplifier is configured to amplify radio-frequency signals using a supply voltage. The radio-frequency signals have different waveforms. The power converter is coupled to the amplifier and configured to provide the supply voltage. The average power tracking module is coupled to the power converter and configured to adjust the supply voltage according to the different waveforms to cause the supply voltage to vary across at least two waveforms of the different waveforms for related average output powers.

Waveform-tailored average power tracking

Methods and apparatus for providing amplifier protection for a radio frequency (RF) front-end circuit. An example RF front-end circuit generally includes an amplifier with a gain, a first sensor configured to sense a first power (or voltage) of a first node coupled to an input of the amplifier, a second sensor configured to sense a second power (or voltage) of a second node coupled to an output of the amplifier, and logic coupled to the first and second sensors. The logic is generally configured to determine that the second power (or voltage) is outside a range based on the gain and the first power (or voltage) and to take an action to protect the amplifier based on the determination. By utilizing the techniques and apparatus described herein, protection can be provided to the amplifier(s) in an RF front-end circuit without significantly impacting the performance of the RF front-end circuit.

Front-end circuitry with amplifier protection

A power amplifier circuit, including: an input node configured to receive a radio frequency (RF) signal; an output node configured to output an amplified RF signal; a main path switchably coupled between the input node and the output node, and including a first plurality of amplification stages to generate a first amplified RF signal; a bypass path switchably coupled between the input node and the output node, and including at least one second amplification stage to generate a second amplified RF signal; and a coupling switch configured to reuse at least a portion of the bypass path to drive the main path to generate a third amplified RF signal.

Reconfigurable power amplifier

Techniques for protecting a power amplifier (PA) are described. In an exemplary design, an apparatus includes (i) a PA module to amplify an input RF signal and provide an output RF signal and (ii) a protection circuit to control a transmitter gain to protect the PA module against high peak voltage. In an exemplary design, the protection circuit includes a set of comparators to quantize an analog input signal and provide digital comparator output signals used to adjust the transmitter gain. In another exemplary design, the protection circuit reduces and increases the transmitter gain with hysteresis. In yet another exemplary design, the protection circuit has faster response to rising amplitude than falling amplitude of the output RF signal. The hysteresis and/or the different rise and fall responses may allow the protection circuit to avoid toggling the transmitter gain under severe load mismatch and to handle time-varying envelope due to amplitude modulation.

Protection circuit for power amplifier

Embodiments of the present disclosure include a bias circuit for generating bias voltages to stacked transistors. In one embodiment, stacked transistors are coupled between an input transistor and an output node. A modulated power supply voltage and an input signal produce a voltage at the output node. The modulated power supply voltage is provided as an input to the bias circuit. Bias voltages are generated that change with the power supply voltage. In one embodiment, particular transistors in the stack are biased so that their control terminals are effectively short circuited when the power supply voltage is reduced.

Bias circuits and methods for stacked devices

Negative voltage generators that do not require level shifters or AC coupling capacitors are disclosed. In an exemplary design, a negative voltage generator includes first, second, third and fourth switches, a capacitor, and a control circuit. The first switch is coupled between an input node and a first node. The second switch is coupled between the first node and circuit ground. The third switch is coupled between a second node and circuit ground. The fourth switch is coupled between the second node and an output node. The input node receives a positive voltage, and the output node provides a negative voltage. The capacitor is coupled between the first and second nodes. The control circuit (e.g., an inverter) generates a control signal having positive and negative voltage levels for the third switch using a negative voltage level at the second node.

Negative voltage generators

A multi-mode multi-band power amplifier (PA) module is described. In an exemplary design, the PA module includes multiple power amplifiers, multiple matching circuits, and a set of switches. Each power amplifier provides power amplification for its input signal when selected. Each matching circuit provides impedance matching and filtering for its power amplifier and provides a respective output signal. The switches configure the power amplifiers to support multiple modes, with each mode being for a particular radio technology. Each power amplifier supports at least two modes. The PA module may further include a driver amplifier and an additional matching circuit. The driver amplifier amplifies an input signal and provides an amplified signal to the power amplifiers. The additional matching circuit combines the outputs of other matching circuits and provides an output signal with higher output power. The driver amplifier and the power amplifiers can support multiple output power levels.

Multi-mode multi-band power amplifier module

Switches with connected bulk for improved switching performance and bias resistors for even voltage distribution to improve reliability are described. In an exemplary design, a switch may include a plurality of transistors coupled in a stack and at least one resistor coupled to at least one intermediate node in the stack. The transistors may have (i) a first voltage applied to a first transistor in the stack and (ii) a second voltage that is lower than the first voltage applied to bulk nodes of the transistors. The resistor(s) may maintain matching bias conditions for the transistors when they are turned off. In one exemplary design, one resistor may be coupled between the source and drain of each transistor. In another exemplary design, one resistor may be coupled between each intermediate node and the first voltage. The resistor(s) may maintain the source of each transistor at the first voltage.

Switches with bias resistors for even voltage distribution

A high linear fast peak detector having a variable bias current and/or a variable bias voltage is described. In an exemplary design, the peak detector includes a transistor, a variable current source, a capacitor, and a feedback circuit. The transistor receives the input signal and provides a source current. The variable current source receives the input signal, provides high bias current when the input signal is low, and provides low bias current when the input signal is high. The capacitor is charged by the source current when the input signal is high and is discharged by the high bias current when the input signal is low. The feedback circuit receives a detected signal from the capacitor and provides higher bias voltage for the transistor when the input signal is high, which results in higher source current from the transistor.

High linear fast peak detector

Level shifters and high voltage logic circuits implemented with MOS transistors having a low breakdown voltage relative to the voltage swing of the input and output signals are described. In an exemplary design, a level shifter includes a driver circuit and a latch. The driver circuit receives an input signal having a first voltage range and provides a drive signal having a second voltage range. The first and second voltage ranges may cover positive and negative voltages or different ranges of positive voltages. The latch receives the drive signal and provides an output signal having the second voltage range. The driver circuit may generate a control signal having a full voltage range based on the input signal and may then generate the drive signal based on the control signal. The level shifter may be used to implement a high voltage logic circuit.

Level shifters and high voltage logic circuits

Techniques for designing a switchable amplifier are described. In one aspect, a switchable amplifier including a core amplifier circuit configured to selectively enable one or more parallel input transistor pairs is described. The core amplifier circuit comprises a permanently enabled input transistor pair. In another aspect, a device operable between a first mode of operation and a second mode of operation comprising a receiver logic circuit for selectably enabling and disabling a plurality of input transistor pairs within a switchable amplifier is described where the switchable amplifier also includes a core amplifier circuit coupled to the receiver logic circuit for selectably enabling and disabling a transistor pair therein. The described switchable amplifiers result in the ability to provide varying amplifier performance characteristics based upon the current mode of operation of the device.

Switchable input pair operational amplifiers

A device with multiple multi-mode low-noise amplifiers (LNAs), each with common operating modes and separate operating frequency bands, are coupled to shared degenerative inductors for common operating modes. Common load inductors are coupled to the multi-mode LNA outputs to reduce the number of load inductors required. The multi-mode LNAs have parallel transistor gain stages and form part of an integrated circuit (IC) for use in a wireless communication receiver. Each multi-mode LNA has the capability to switch between at least one higher linearity transistor gain stage and at least one lower linearity transistor gain stage for different operating modes. Multiple lower linearity transistor gain stages for different multi-mode LNAs may be merged into a single lower linearity transistor gain stage shared among multiple multi-mode LNAs through multiple RF switches between a set of common RF inputs and common inputs and common input matching networks.

Multiple multi-mode low-noise amplifier receiver with shared degenerative inductors

An apparatus for implementing phase rotation at baseband frequency for transmit diversity may include a primary transmit signal path and a diversity transmit signal path. Both the primary transmit signal path and the diversity transmit signal path may receive a primary transmit signal. A signal selector within the diversity transmit signal path may perform phase rotation with respect to the primary transmit signal while the primary transmit signal is at a baseband frequency, thereby producing a diversity transmit signal.

Methods and apparatus for implementing phase rotation at baseband frequency for transmit diversity

Exemplary embodiments of the disclosure are directed to down-converting an RF signal of a transmitter to baseband, filtering the down-converted signal, and generating a composite signal based on the filtered down-converted signal and a transmission based-band signal.

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San Diego, CA, United States of America

Marco Cassia