Patent application number | Description | Published |
20090115253 | METHODS AND APPARATUSES FOR SELECTABLE VOLTAGE SUPPLY - 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. | 05-07-2009 |
20090121759 | FAST-SWITCHING LOW-NOISE CHARGE PUMP - 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. | 05-14-2009 |
20090261917 | AUXILIARY VARACTOR FOR TEMPERATURE COMPENSATION - 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. | 10-22-2009 |
20090278620 | VCO CAPACITOR BANK TRIMMING AND CALIBRATION - 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. | 11-12-2009 |
20100026383 | DIRECT CURRENT (DC) OFFSET CORRECTION USING ANALOG-TO-DIGITAL CONVERSION - Techniques for reducing or eliminating DC (direct current) offset in transmitters are disclosed. An apparatus for DC offset reduction may include a converter, a digital engine, and a plurality of programmable current supplies. The converter is configured to provide digital representations of a plurality of DC currents associated, respectively, with a plurality of differential signal legs. The digital engine is configured to receive the digital representations and to produce instructions for generating compensating currents for the plurality of differential signal legs based on comparisons, respectively, between each of the digital representations and a calibration current. The programmable current supplies correspond, respectively, to the differential signal legs. The current supplies are configured to inject the compensating currents into the differential signal legs, respectively, to reduce DC offset between the differential signal legs, based upon the instructions. The instructions allow one-shot DC offset correction, instead of successive approximation for DC offset correction. | 02-04-2010 |
20100148873 | TECHNIQUES FOR IMPROVING AMPLIFIER LINEARITY - 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. | 06-17-2010 |
20100225402 | VCO TUNING WITH TEMPERATURE COMPENSATION - Techniques for setting a fine tuning input signal Vtune for a voltage-controlled oscillator (VCO) in a coarse tuning mode of the VCO. In an exemplary embodiment, the fine tuning input signal during coarse tuning mode is made temperature-dependent to account for possible variation of Vtune over temperature during fine tuning mode. Methods and apparatuses employing the techniques are further described. | 09-09-2010 |
20100295622 | SYSTEMS AND METHODS FOR SELF TESTING A VOLTAGE CONTROLLED OSCILLATOR IN AN OPEN LOOP CONFIGURATION - 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. | 11-25-2010 |
20110291716 | FAST-SWITCHING LOW-NOISE CHARGE PUMP - 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. | 12-01-2011 |
20120187994 | SYSTEM FOR I-Q PHASE MISMATCH DETECTION AND CORRECTION - 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. | 07-26-2012 |
20140253255 | VOLTAGE CONTROLLED OSCILLATOR BAND-SELECT FAST SEARCHING USING PREDICTIVE SEARCHING - 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. | 09-11-2014 |