Qualcomm Incorporated

Sang-Oh Lee

Jeongsik Yang

Mazhareddin Taghivand

Cheng-Han Wang

Shen Wang

Young Gon Kim

Sean Joel Lyn

Yongwang Ding

Conor Donovan

Hye Jin Song

Aristotele Hadjichristos

Cormac S Conroy

Marco Cassia

Hong Sun Kim

Thinh Cat Nguyen

Xiaoyong Li

Chan Hong Park

Ngar Loong Alan Chan

David Ta-hsiang Lin

Jianlei Shi

Jin Wook Kim

Hai Huang

Apparatuses and methods are disclosed regarding a multiband transmitter. In an example aspect, an apparatus for processing signals for wireless transmission includes a wireless interface device. The wireless interface device includes an upconverter, a tunable filter, and a driver amplifier. The upconverter has an output and is configured to upconvert a baseband frequency to a radio frequency based on a local oscillator signal. The tunable filter has an input and an output; the input of the tunable filter is coupled to the output of the upconverter. The driver amplifier has an input; the input of the driver amplifier is coupled to the output of the tunable filter.

Multiband transmitter

An area-efficient balun and a method for signal processing using such a balun. One example balun generally includes a winding and a clamping circuit. The winding is formed by a coiled trace including a first portion having a first trace width and a second portion having a second trace width, the second trace width being narrower than the first trace width. The clamping circuit has a first terminal and a second terminal, the first terminal of the clamping circuit being coupled to the first portion of the coiled trace.

Area-efficient balun

A transformer is described. The transformer includes a primary coil and a first secondary coil. A first coupling occurs between the first secondary coil and the primary coil. The transformer also includes a second secondary coil. A second coupling occurs between the second secondary coil and the primary coil. The first secondary coil is separated from the second secondary coil to prevent coupling between the first secondary coil and the second secondary coil. A first width of the first secondary coil is configured independently of a second width of the second secondary coil.

Transformer feedback voltage controlled oscillator (VCO)

Certain aspects of the present invention provide methods and apparatus for detecting phase shift between signals, such as local oscillating signals in adjacent transceiver paths. One example circuit for phase detection generally includes a mixer configured to mix a first input signal having a first frequency with a second input signal having a second frequency to produce an output signal having frequency components at the sum of and the difference between the first and second frequencies; a filter connected with the mixer and configured to remove one of the frequency components at the sum of the first and second frequencies, thereby leaving a DC component; and an analog-to-digital converter (ADC) (e.g., a comparator) connected with the filter and configured to determine whether the first input signal is in-phase or out-of-phase with the second input signal based on a comparison between the DC component and a reference signal.

Phase detecting circuit for interchain local oscillator (LO) divider phase alignment

A method, an apparatus, and a computer program product are provided. The apparatus tunes a frequency provided by a VCO. The apparatus determines a relative capacitance change associated with a first frequency and a desired frequency from a look-up table. The apparatus adjusts a capacitor circuit in the VCO based on the determined relative capacitance change determined from the look-up table in order to tune from the first frequency to the desired frequency. The apparatus determines that the frequency provided by the VCO is a second frequency different than the desired frequency after adjusting the capacitor circuit. The apparatus performs an iterative search to further adjust the capacitor circuit when a difference between the second frequency and the desired frequency is greater than a threshold.

Voltage controlled oscillator band-select fast searching using predictive searching

System for I-Q phase mismatch detection and correction. An apparatus to correct a phase mismatch between I and Q signals includes a correction circuit configured to continuously compare a reference signal and a phase error signal associated with the I and Q signals to generate an I bias signal and a Q bias signal, a first CMOS buffer configured to receive the I signal and the I bias signal and output a phase adjusted I signal based on the I bias signal, and a second CMOS buffer configured to receive the Q signal and the Q bias signal and output a phase adjusted Q signal based on the Q bias signal.

System for I-Q phase mismatch detection and correction

In one embodiment of the invention, a method for a charge pump is disclosed. The method includes biasing a plurality of transistors; switching a pair of main transistor switches to apply or remove a net charge on an output terminal though the biased transistors; and turning on auxiliary transistor switches when the main transistor switches are turned off. The auxiliary transistor switches when turned on provide an auxiliary equalizing path to nodes between the main transistor switches and the biased transistors. The auxiliary equalizing path equalizes voltages between the intermediate nodes to rapidly turn off the biased transistors and reduce noise on the output terminal of the charge pump.

Fast-switching low-noise charge pump

Methods and apparatus for self testing a multiband voltage controlled oscillator (VCO) are disclosed. A tuning voltage of the VCO is adjusted where the output of the VCO does not affect the input to the VCO. Frequency bands in the VCO are selected. Output frequencies of the VCO are measured.

Systems and methods for self testing a voltage controlled oscillator in an open loop configuration

Techniques for compensating for the effects of temperature change on voltage controlled oscillator (VCO) frequency are disclosed. In an embodiment, an auxiliary varactor is coupled to an LC tank of the VCO. The auxiliary varactor has a capacitance controlled by a temperature-dependant control voltage to minimize the overall change in VCO frequency with temperature. Techniques for generating the control voltage using digital and analog means are further disclosed.

Auxiliary varactor for temperature compensation

Techniques for improving the linearity of a cascode amplifier. In an exemplary embodiment, an auxiliary common-gate amplifier is provided in parallel with the principal cascode branch. The auxiliary common-gate amplifier samples a cascoded node in the principal cascode branch. The auxiliary common-gate amplifier generates a current which, when combined with the current generated by the principal cascode branch, cancels a distortion component to generate an output current with improved linearity characteristics. In an exemplary embodiment, a phase shifting network couples the cascoded node to the auxiliary common-gate amplifier, and may include, e.g., a capacitor coupled to an inductor.

Techniques for improving amplifier linearity

Techniques are disclosed for trimming a capacitance associated with a capacitor bank for use in a voltage-controlled oscillator (VCO). In an embodiment, each capacitance is sub-divided into a plurality of constituent capacitances. The constituent capacitances may be selectively enabled or disabled to trim the step sizes of the capacitor bank. Further techniques are disclosed for calibrating the trimmable capacitance to minimize step size error for the capacitor bank.

VCO capacitor bank trimming and calibration

A circuit which selects a supply voltage from a plurality of voltage supplies is presented. The circuit includes a first transistor configured to select a first voltage supply, a second transistor configured to select a second voltage supply, a first parasitic current inhibitor coupled the first transistor, the first voltage supply, and the second voltage supply, where the first parasitic current inhibitor automatically utilizes the voltage supply providing the highest voltage for preventing a substrate current from flowing through a bulk node of the first transistor, and a second parasitic current inhibitor coupled the second transistor, the first voltage supply, and the second voltage supply, where the second parasitic current inhibitor automatically utilizes the voltage supply providing the highest voltage for preventing a substrate current from flowing through a bulk node of the second transistor.

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Cupertino, CA, United States of America

Sang-Oh Lee