Qualcomm Incorporated

Other

Jose Cabanillas

Calogero Davide Presti

Prasad S Gudem

David Francis Berdy

Li-chung Chang

Marco Cassia

Maulin Pareshbhai Bhagat

John Woolfrey

Aristotele Hadjichristos

Li Liu

Jeremy Mark Goldblatt

Babak Nejati

Christian Holenstein

Alper Genc

Yu Zhao

Anup Savla

Namsoo Kim

Guy Klemens

Ryan Scott Castro Spring

Norman L Frederick, Jr

Sai Kwok

Cristian Marcu

Per O Kristensen

Mohan V Puntambekar

Jiang Chen

David Love

Euichan Moon

Jin Cho

Li-Chung Chang

Jr Norman L Frederick

Sai Chong Kwok

A (RF) switching system for minimizing received signal leakage during switching including a plurality of band filters comprising a first band filter, a second band filter, and a third band filter, first and a second antenna, and a switch configured to selectively couple the first, second and third filters to the first and second antennas and configured to receive complementary control signals, wherein at least the first and the second filter are configured to be simultaneously coupled to the first antenna and the switch is further configured to delay at least one of the complementary control signals when the switch, in response to the complementary control signals, is configured to selectively connect the first antenna to the third filter instead of the second filter while the first filter is coupled to the first antenna and a first communication path through the first filter to the first antenna is active.

System and method to reduce unwanted receive signal leakage during switching

In certain aspects, a system includes a first filter, a second filter, a dummy load, and a switching circuit coupled to the first filter, the second filter, and the dummy load, and coupled to a first antenna and a second antenna. In a first mode, the switching circuit couples the first filter and the second filter to the first antenna, and, in a second mode, the switching circuit couples the first filter and the third filter to the first antenna and couples the second filter to the second antenna. In certain aspects, the dummy load includes a third filter.

Dynamic radio frequency loading change mitigation

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 bias circuit with embedded envelope detection includes a bias circuit stage coupled to an envelope detector circuit to increases a bias provided to a power amplifier as a function of an incoming envelope signal. The envelope detector circuit includes a first source/emitter follower transistor, a current source, and a filter to generate a baseband envelope signal. The current source is coupled to an output node of the first source/emitter follower transistor and the filter is also coupled to the output node of the first source/emitter follower transistor. The bias circuit stage includes one or more replica transistors that replicate transistors of the power amplifier or power amplifier core stage, an envelope detector replica transistor and a replica of the current source of the envelope detector circuit.

Source follower based envelope tracking for power amplifier biasing

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

A circuit including: a power amplifier configured to provide amplified signals to a load; an impedance matching network disposed between the power amplifier and the load, the impedance matching network comprising an adjustable impedance unit; and a feedback loop comprising a rectifier, the rectifier being coupled with an output of the power amplifier, the feedback loop further comprising and impedance control circuit configured to receive a signal from the rectifier and to control the adjustable impedance unit in response to the signal from the rectifier.

Systems and methods providing loadline modulation of a power amplifier

Techniques to implement a filter for a selected signal path by reusing a circuit component in an unselected signal path are disclosed. In an exemplary design, an apparatus includes first, second, and third circuits. The first circuit passes a first radio frequency (RF) signal to an antenna when a first signal path is selected. The second circuit passes a second RF signal to the antenna when a second signal path is selected. The third circuit is selectively coupled to the first circuit, e.g., via a switch. The first and third circuits form a filter for the second RF signal (e.g., to attenuate a harmonic of the second RF signal) when the second signal path is selected and the first signal path is unselected. The first circuit may include a series inductor, and the third circuit may include a shunt capacitor.

Filters for multi-band wireless device

The present disclosure includes circuits and methods for wideband biasing. In one embodiment, an amplifier includes a cascode transistor between an input and an output of the amplifier. The cascode transistor receives a bias from a bias circuit comprising a resistor between the power supply and a first node, a resistor between the first node and a reference voltage, and a capacitor between the power supply and the first node. The power supply may be a modulated power supply, which is coupled through the bias circuit to a capacitance at the control terminal of the cascode transistor. An inductor is configured between a terminal of the cascode transistor and the power supply. The inductor may isolate the output from the modulated supply signal.

Wideband bias circuits and methods

The present disclosure includes circuits and methods for wideband biasing. In one embodiment, an amplifiers includes a cascode transistor between an input and an output of the amplifier. The cascode transistor receives a bias from a bias circuit comprising a resistor between the power supply and a first node, a resistor between the first node and a reference voltage, and a capacitor between the power supply and the first node. The power supply may be a modulated power supply, which is coupled through the bias circuit to a capacitance at the control terminal of the cascode transistor. An inductor is configured between a terminal of the cascode transistor and the power supply. The inductor may isolate the output from the modulated supply signal.

An impedance matching circuit with at least one tunable notch filter for a power amplifier is disclosed. The power amplifier amplifies an input radio frequency (RF) signal and provides an amplified RF signal. The impedance matching circuit performs output impedance matching for the power amplifier and includes at least one tunable notch filter. Each tunable notch filter has a notch that can be varied in frequency to provide better attenuation of an undesired signal. The at least one tunable notch filter attenuates at least one undesired signal in the amplified RF signal. The at least one tunable notch filter may include (i) a first tunable notch filter to attenuate a first undesired signal at a second harmonic of the amplified RF signal and/or (ii) a second tunable notch filter to attenuate a second undesired signal at a third harmonic of the amplified RF signal.

Impedance matching circuit with tunable notch filters for power amplifier

Techniques for bypassing a supply voltage for an amplifier are disclosed. In an exemplary design, an apparatus includes an amplifier and an adjustable bypass circuit. The amplifier (e.g., a power amplifier) receives a supply voltage from a supply source. The adjustable bypass circuit is coupled to the supply source and provides bypassing for the supply voltage. The adjustable bypass circuit includes an adjustable capacitor or a fixed capacitor coupled to an adjustable resistor. The supply source may be (i) a power supply source providing a fixed supply voltage for the amplifier or (ii) an envelope tracker providing a variable supply voltage for the amplifier.

Adjustable bypass circuit for a supply voltage for an amplifier

Techniques for reducing undesired source degeneration inductance are disclosed. In an exemplary design, an apparatus includes first and second connections. The first connection includes a first parasitic inductance acting as a source degeneration inductance of an amplifier. The second connection includes a second parasitic inductance magnetically coupled to the first parasitic inductance to reduce the source degeneration inductance of the amplifier. The amplifier (e.g., a single-ended power amplifier) may be coupled to circuit ground via the first connection. An impedance matching circuit may be coupled to the amplifier and may include a circuit component coupled to circuit ground via the second connection. The first connection may be located sufficiently close to (e.g., within a predetermined distance of) the second connection in order to obtain the desired magnetic coupling between the first and second parasitic inductances.

Amplifier with reduced source degeneration inductance

A receiver includes a jammer detector configured to detect the presence or the absence of jamming in a communication signal within a gain state. The receiver further includes an amplifier configured to amplify the communication signal in a high linearity receiving mode or a low linearity receiving mode, wherein the high linearity receiving mode corresponds with a lower gain for the gain state in the amplifier relative to that of the low linearity receiving mode. In addition, the receiver includes a processing unit coupled to the jammer detector, the processing unit being configured to control the amplifier to amplify the communication signal in either the high linearity receiving mode or the low linearity receiving mode, based on the output of the jammer detector detecting the presence or the absence of jamming in the communication signal. A method is also provided for processing a communication signal in a receiver.

Reconfigurable high linearity low noise figure receiver requiring no interstage saw filter

A wireless communication device includes a component operating in a single frequency mode. The component includes a first differential branch that includes first input nodes and first output nodes. The first output nodes are coupled to ground. A second differential branch includes second input nodes, second output nodes, and a first planar inductor coupling a first terminal and a second terminal to ground. A third differential branch includes third input nodes, third output nodes, and a second planar inductor. The second planar inductor is formed within the first planar inductor of the second differential branch and couples a third terminal and a fourth terminal to ground. The third and fourth terminals are electrically independent from the first planar inductor and the first and second terminals. The second and third differential branches form a dual inductor circuit.

Dual inductor circuit for multi-band wireless communication device

This disclosure describes a dual inductor circuit, which may be particularly useful in a mixer of a wireless communication device to allow the mixer to operate for two different frequency bands or in a multi-differential branch low noise amplifier wherein each of the differential branches possess a different set of gain and linearity characteristics for a signal operating at the same frequency. The dual inductor circuit comprises an inductor-within-inductor design in which a small inductor is disposed within a large inductor. The two inductors may share a ground terminal, but are otherwise physically separated and independent from one another. Terminals of the inner inductor, for example, are not tapped from the outer inductor, which can reduce parasitic effects and electromagnetic interference relative to tapped inductor designs. The independence of the inductors also allows the different inductors to define different resonance frequencies or gain and linearity characteristics, which is desirable.

Growing community of inventors

San Diego, CA, United States of America

Jose Cabanillas