Qualcomm Incorporated

Nokia Technologies Oy

Zeku Technology (shanghai) Corp., Ltd.

Wei Zhuo

Ojas Choksi

Himanshu Khatri

Solti Peng

Aristotele Hadjichristos

Li-chung Chang

Prasad Srinivasa Siva Gudem

Faramarz Sabouri

Bo Wang

Gurkanwal Singh Sahota

Hasnain Lakdawala

Roger Brockenbrough

Timothy Donald Gathman

Rui Li

Rahul Karmaker

Tzu-Wang Pan

Joung Won Park

Janakiram Ganesh Sankaranarayanan

Wenbang Xu

Li-Chung Chang

Tsu-Wang Pan

Circuits and methods for operating a receiver in a communication system is disclosed. The receiver analyzes interference power levels at two or more frequency regions within a received signal. The receiver selects a low-power circuit based on the frequency-analyzed interference power for processing the received signal.

Receiver power-management mechanism and related methods of operation

Embodiments of apparatus and method for calibration of a transceiver (including a transmitter and a receiver) are disclosed. In an example, a method for transmitter quadrature (or IQ) mismatch and receiver quadrature (or IQ) mismatch calibration can include controlling the transmitter to send a first transmit signal to the receiver with a delay between an output of the transmitter and an input of the receiver. The method can also include controlling the transmitter to send a second transmit signal to the receiver without the delay between the output of the transmitter and the input of the receiver. The method can further include obtaining compensation coefficients of the transceiver based on the sending of the first transmit signal and the sending of the second transmit signal.

Delay-line based transceiver calibration

Certain aspects of the present disclosure provide methods and apparatus for amplifying an input signal. One example apparatus is a differential amplifier that includes a positive input node, a negative input node, a positive output node, a negative output node, a positive input transistor having a gate coupled to the positive input node and having a drain coupled to the negative output node, a negative input transistor having a gate coupled to the negative input node and having a drain coupled to the positive output node, a first common-gate amplifier having an output coupled to the negative output node, a second common-gate amplifier having an output coupled to the positive output node, a first capacitive element coupled between the negative input node and an input of the first common-gate amplifier, and a second capacitive element coupled between the positive input node and an input of the second common-gate amplifier.

High gain-bandwidth product (GBW) amplifier with passive feedforward compensation

A filter circuit may include a first path having a first complex baseband filter. The circuit may further include a second path having a second complex baseband filter. The circuit may further include a combiner coupled to an output of the first complex baseband filter and an output of the second complex baseband filter.

Filter circuit

Techniques for improving performance of a transformer shared amongst a plurality of operating modes. In an aspect, first and second primary windings of a transformer are coupled to an AC ground voltage. Primary windings are mutually coupled to a secondary winding of the transformer. To render the second primary winding inactive, e.g., when operating in a first mode, a switch coupling the second primary winding to the common reference voltage is opened. Similarly, when it is desired to render the first primary winding inactive, e.g., when operating in a second mode, a switch coupling the first primary winding to the common reference voltage is opened. In this manner, the inactive primary winding advantageously does not load the secondary winding. Further aspects provide for, e.g., extending the techniques to more than two modes, and alternative techniques to mutually couple the signal from the primary to the secondary winding.

Port isolation in shared transformers

A single-ended receiver is described. The single-ended receiver includes a multi-port transformer that outputs a differential signal. The multi-port transformer includes a first primary coil that is coupled to an output of a first low noise amplifier. The multi-port transformer also includes a second primary coil that is coupled to an output of a second low noise amplifier. The multi-port transformer further includes a first secondary coil. The single-ended receiver also includes a shared mixer that receives the differential signal from the multi-port transformer.

Single ended receiver with a multi-port transformer and shared mixer

An apparatus including: at least one receiver having injection points and having at least an amplifier and a transformer; and a plurality of isolation switches coupled to injection points of the at least one receiver, the plurality of isolation switches configured to route a calibration signal generated by a transmitter to one of the injection points.

On-chip linearity calibration

Bias voltage generators that can generate variable bias voltages for transistors in mixers and other circuits are disclosed. In an exemplary design, an apparatus (e.g., a wireless device or an integrated circuit (IC)) includes at least one transistor and a bias voltage generator. The transistor(s) have a threshold voltage and receive a bias voltage. The bias voltage generator generates the bias voltage based on changes to the threshold voltage of the transistor(s), e.g., due to IC process and/or temperature. In an exemplary design, the bias voltage generator includes a replica transistor that tracks the transistor(s) and an op-amp that provides a gate voltage for the replica transistor. The bias voltage is generated based on the gate voltage. The bias voltage generator may generate the bias voltage (i) to track the threshold voltage of the transistor(s) in a first mode or (ii) based on a fixed voltage in a second mode.

Threshold tracking bias voltage for mixers

A wireless communication device configured for reducing Tx leakage in a receive signal is described. The wireless communication device includes a transceiver chip. The transceiver chip includes a receiver, a feedback receiver and a transmitter. The wireless communication device also includes a Tx leakage signal reduction module. The Tx leakage signal reduction module reuses the feedback receiver.

Tunable notch filter using feedback through an existing feedback receiver

Exemplary embodiments are directed to providing electrostatic discharge (ESD) protection of a cascode device of an amplifier. In an exemplary embodiment, a transistor is configured to receive a bias voltage and at least one circuit element coupled to the transistor and configured to receive an input voltage via an input pad. Additionally at least one diode can be coupled to a drain of the first transistor and configured to limit a voltage potential at an internal node of the amplifier caused by the input pad.

Electrostatic discharge protection of amplifier cascode devices

Power supply rejection in a single-ended receiver, through impedance balancing, is described. The single-ended receiver includes a first low noise amplifier and a second low noise amplifier. The single-ended receiver also includes a multi-port coupled transformer that outputs a differential signal. The multi-port coupled transformer includes a first primary coil that is coupled to an output of the first low noise amplifier and a second primary coil. The single-ended receiver also includes balancing impedances at the output of each of the low noise amplifiers. These impedances can be configured such that the on impedance of the first low noise amplifier equals the combined impedance of the off impedance of the second low noise amplifier and the balancing impedance. This balancing of impedances on the first and second primary coils results in power supply rejection of noise and spurious signals.

Impedance balancing for power supply rejection in single-ended receivers

Amplifiers with shunt switches to mitigate interference are disclosed. In an exemplary design, an apparatus includes an amplifier and a shunt switch. The amplifier has an input operatively coupled to an input/output (I/O) pad of an integrated circuit (IC) chip. The shunt switch grounds the amplifier when the shunt switch is closed. The shunt switch is isolated from the I/O pad and the amplifier input. The amplifier may be a low noise amplifier (LNA) or some other type of amplifier. In an exemplary design, the shunt switch is isolated from the I/O pad by a series switch. The series switch and the shunt switch may be closed when the amplifier is disabled and may be opened when the amplifier is enabled.

Amplifiers with shunt switches

A communication device includes a transmitter and a receiver. The receiver mixes a local oscillator (LO) signal with the received signal to downconvert the received signal to an intermediate frequency (IF). The LO path that feeds the LO signal to the downconverting mixer is controlled based on the transmit power of the transmitter. For high transmit power, the drive of the LO path is increased, thereby increasing the signal-to-noise ratio of the LO signal input into the mixer. For low transmit power levels, the drive to the LO path is decreased, reducing power consumption in the communication device. In this way, receiver path noise due to mixing of the LO phase noise with the self-generated transmitter signal is selectively controlled while incurring lower power consumption penalty. The communication device may be an access terminal configured for communication with a cellular radio network.

Adjustable local oscillator path in a communication device with a transmitter

A downconversion mixer includes a configurable gate or bulk bias voltage to allow calibration and correction of device offsets. Calibration may be performed on the configurable bias voltages to minimize IM2 distortion in the mixer. The techniques have minimal impact on voltage headroom, impose no requirement for a signal path to be phase-matched with a calibration path, and are particularly well-suited for passive mixers.

Offset correction for passive mixers

A method according to one embodiment includes using a quadrature set of local oscillator signals having duty cycles of substantially less than fifty percent to perform a mixing operation on a radio-frequency current signal. Other embodiments include using a quadrature set of local oscillator signals having duty cycles of less than twenty-five percent.

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San Diego, CA, United States of America

Wei Zhuo