| Patent application number | Description | Published |
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| 20090273502 | Fast, efficient reference networks for providing low-impedance reference signals to signal converter systems - Reference network embodiments are provided for use in pipelined signal converter systems. The network embodiments are fast and power efficient and they generate low-impedance reference signals through the use of a complimentary common-drain output stage, an output current valve inserted between transistors of the output stage, and a controller. The controller is configured to provide gate voltages to the output current valve to thereby establish a substantially-constant output current. The controller is further configured to provide gate voltages to the output stage to establish top and bottom reference voltages about the output current valve that are spaced from a common-mode voltage. This reference structure maintains a constant output current as the span between the top and bottom reference voltages is selectively altered. In different embodiments, transistors of the output current valve are arranged in a drain-to-source-coupled configuration and in a source-coupled configuration. | 11-05-2009 |
| 20100019946 | Amplifier networks with controlled common-mode level and converter systems for use therewith - Effective control of the common-mode level of amplifiers is obtained through control structures (both closed-loop and open-loop structures) which are directed to various amplifier functions such as the reduction of amplifier loading, accurate sensing of common-mode levels, mitigation of headroom restraints, and proper transistor biasing. This common-mode control is especially useful in multiplying analog-to-digital converters (MDACs) of signal processing systems. | 01-28-2010 |
| 20100073210 | Pipelined converter systems with enhanced linearity - Signal converter system embodiments are provided to substantially reduce symmetrical and asymmetrical conversion errors. Signal-processing stages of these embodiments may include a signal sampler in addition to successively-arranged signal converters. In system embodiments, injected analog dither signals are initiated in response to a random digital code. They combine with a system's analog input signal and the combined signal is processed down randomly-selected signal-processing paths of the converter system to thereby realize significant improvements in system linearity. Because these linearity improvements are realized by simultaneous processing of the input signal and the injected dither signal, a combined digital code is realized at the system's output. A first portion of this combined digital code corresponds to the analog input signal and a second portion corresponds to the injected analog dither signal. The final system digital code is realized by subtracting out the second portion with a back-end decoder that responds to the random digital code. | 03-25-2010 |
| 20100109927 | RESIDUE GENERATORS FOR REDUCTION OF CHARGE INJECTION IN PIPELINED CONVERTER SYSTEMS - Pipelined converter systems include a plurality of converter stages in which some stages generate and pass a residue signal to a succeeding stage for further conversion. The generation of the residue signal can inject spurious charges into a reference source that is used in the generation. The spurious charges reduce the accuracy of the residue signal and the accuracy of the system. Residue generator embodiments are thereby formed to provide reduction charges to the reference source that are arranged to oppose and reduce the spurious charges. This reduction of spurious charges significantly enhances system accuracy and linearity. | 05-06-2010 |
| 20100149015 | FAST, EFFICIENT REFERENCE NETWORKS FOR PROVIDING LOW-IMPEDANCE REFERENCE SIGNALS TO SIGNAL PROCESSING SYSTEMS - Reference network embodiments are provided for use in pipelined signal converter systems. The network embodiments are fast and power efficient and they generate low-impedance reference signals through the use of at least one output transistor, a diode-coupled transistor coupled to the output transistor, and a controller. The controller is configured to provide a backgate voltage to the diode-coupled transistor to thereby establish a substantially-constant output current. The controller is further configured to provide a gate voltage to the output transistor to establish a reference voltage. | 06-17-2010 |
| 20100301930 | REDUCING DEVICE PARASITICS IN SWITCHED CIRCUITS - A system and method are provided to reduce the influence of parasitic capacitance at the drain and source of MOS transistors of a sampling circuit. In one embodiment, the bulk is left floating during a first phase and refreshed during a second phase. During the first phase, the effective parasitic contribution of the drain or source of a MOS transistor is lower due to the series combination of Cj and Cw capacitances. In another embodiment, a large resistance provides a path from a reference voltage to the bulk of a MOS transistor, thereby resulting in an effective parasitic capacitance of the series combination of Cj and Cw. Advantageously, the parasitic capacitance is reduced as well as its non-linear effect, the operating speed is improved, as well as the signal distortion and noise. | 12-02-2010 |
| 20110006815 | HIGH PERFORMANCE VOLTAGE BUFFERS WITH DISTORTION CANCELLATION - A voltage buffer may include a first signal path extending from an input terminal to an output terminal in which the first signal path further may include a buffer transistor that may have a control terminal, and a first and second current terminals responsive to the control terminal. In the first signal path, the control terminal may be connected to the input terminal, the first current terminal may be connected to the output terminal, and the first signal path may supply a load current to a load device responsive to an input signal at the input terminal. The voltage buffer further may include a second signal path extending from the input terminal to a current source node. The second signal path may include a replica load device. The voltage buffer further may include a current source supplying substantially constant current and coupled to the current source node. The voltage buffer further may include a current buffer positioned between the current source node and the output node in which the current buffer may direct a replica current from the second signal path responsive to the input signal and the substantially constant current from the current source to the buffer transistor. | 01-13-2011 |
| 20110210877 | CALIBRATION METHODS AND STRUCTURES FOR PIPELINED CONVERTER SYSTEMS - Calibration methods and structures are provided for pipelined analog-to-digital converter systems. They are arranged to process samples of the digital codes with an algorithm that is preferably configured to repeatedly update an estimate of the transfer function with the difference between one of the input signals and the analog equivalent of the corresponding digital code. The calibration methods and structures are further configured to calibrate the transfer function of the converter stage wherein the samples are selected in accordance with various steps. These steps can include the step of injecting dither signals into a flash portion and an MDAC portion of the converter stage to thereby maintain dynamic range. They can also include the step of limiting the samples to those processed through a selected subrange of the subranges. They can further include the step of limiting the samples to those in which the absolute value of the input signals is less that 0.25 of the selected subrange and the absolute value of the dither signals is less that 0.25 of the selected subrange. If the selected subrange is not a central subrange, the steps can further include the step of shifting the samples by a distance between the selected subrange and the central subrange. | 09-01-2011 |
| 20120038417 | INTEGRATED CIRCUIT FOR REDUCING NONLINEARITY IN SAMPLING NETWORKS - An integrated circuit allows for the correction of distortion at an input of a sampling network. The integrated circuit contains a first bootstrap circuit to drive a sampling network transistor and a second bootstrap circuit to separate the back-gate terminal of the transistor from a voltage input by a resistance inserted in series. The presence of the inserted resistance counteracts the effect of the nonlinear back-gate capacitance on the distortion at the input. | 02-16-2012 |
| 20120092198 | SYSTEM AND METHOD OF ANALOG-TO-DIGITAL CONVERTERS - An analog-to-digital converter system that includes a pipeline including N successively-cascaded signal converters, each converting, according to a first clock signal, a respective portion of an input signal of the pipeline into digital codes, a code aligner for receiving and aligning the digital codes from the signal converters in the pipeline into a digital output of the system, an error extractor coupled to an amplifier input node of a selected one signal converter via a first switch for extracting an error signal, and a load system coupled to the amplifier input node of the selected one signal converter via a second switch. | 04-19-2012 |
| 20120274492 | METHOD FOR IMPROVING THE PERFORMANCE OF THE SUMMING-NODE SAMPLING CALIBRATION ALGORITHM - An integrated circuit allows for the isolation of the input of an analog-to-digital converter (ADC) from a summing-node (SNS) algorithm. The integrated circuit contains a gating device that is controlled by bits of a flash analog-to-digital converter (ADC) to gate input samples to sub-ranges that are used by the SNS algorithm. A single sub-range is chosen to be used by the SNS algorithm. | 11-01-2012 |
| 20120319877 | SYSTEM AND METHOD OF ANALOG-TO-DIGITAL CONVERTERS - An analog-to-digital converter system that includes a pipeline of successively-cascaded signal converters, each operating alternatively in a first circuit configuration and a second circuit configuration, an error estimator coupled to the pipeline to receive the digitized error for estimating an amplifier gain of the present signal converter stage, and a code aligner/corrector that temporally aligns and corrects the digital codes received from the successively-cascaded signal converters to provide a digital out of the ADC system. | 12-20-2012 |
| 20120319879 | METHOD FOR MODIFYING THE LMS ALGORITHM TO REDUCE THE EFFECT OF CORRELATED PERTURBATIONS - A process allows for the modification of the least-means-square (LMS) algorithm to remove perturbations associated with measured signals in an analog-to-digital converter (ADC). The process includes measuring the perturbations and determining a coefficient associated with the perturbations. The LMS algorithm is modified in accordance with whether a digital or an analog correction of the inter-stage error of a residue amplifier on the ADC is to be made. | 12-20-2012 |
| 20130033302 | INPUT SWITCHES IN SAMPLING CIRCUITS - A switch may include a MOS transistor alternatively operating in an ON phase and an OFF phase, a first voltage level shifter, and a second voltage level shifter. The MOS transistor may include a source for receiving an input signal, a drain for connecting to a load, and a gate. The first voltage level shifter may be selectively coupled between the source and the gate during the ON phase, and the second voltage level shifter may be selectively coupled between the gate and the source during the OFF phase. | 02-07-2013 |
| 20130120171 | REDUCING THE EFFECT OF NON-LINEAR KICK-BACK IN SWITCHED CAPACITOR NETWORKS - A method and device involve a circuit having a switched capacitor network that is switchably connected to an input signal. A randomly determined amount of dither is injected into a circuit having a switched capacitor network that is switchably connected to an input signal. After injecting the dither, at least one correlation value is determined. The correlation value(s) indicates a degree of correlation between the injected dither and an output of the circuit. Distortion caused by an amount of charge kicked back into the circuit when the switched capacitor network is reconnected to the input signal may then be reduced. The reduction is calculated as a function of the correlation value(s). | 05-16-2013 |
| 20130120172 | METHOD AND DEVICE FOR REDUCING INTER-CHANNEL COUPLING IN INTERLEAVED AND MULTI-CHANNEL ADCs - A method and a corresponding device for reducing inter-channel coupling in a circuit having a plurality of channels includes injecting a randomly determined amount of dither into a first channel of a circuit having a plurality of channels, and after injecting the dither, obtaining an output signal of a second channel in the plurality of channels. A correlation value indicating a degree of correlation between the injected dither and the output signal is determined, and an amount of charge applied to the second channel due to cross-coupling with the first channel is reduced. The amount of the reduction is calculated as a function of the correlation value. | 05-16-2013 |
| 20130120174 | CORRELATION-BASED BACKGROUND CALIBRATION FOR REDUCING INTER-STAGE GAIN ERROR AND NON-LINEARITY IN PIPELINED ANALOG-TO-DIGITAL CONVERTERS - A method and a corresponding device for calibrating a pipelined analog-to-digital converter (ADC) involve injecting a randomly determined amount of dither into one of a flash component and a multiplying digital-to-analog converter (MDAC) in at least one stage in the ADC. For each stage of the at least one stage a correlation procedure is performed to estimate, based on an output of the ADC, an amount of gain experienced by the injected dither after propagating through the stage. The stage is then calibrated based on its respective gain estimate. | 05-16-2013 |
| 20130120175 | CALIBRATING TIMING, GAIN AND BANDWIDTH MISMATCH IN INTERLEAVED ADCs - A method and a corresponding device for calibrating an interleaved analog-to-digital converter (ADC) involve injecting a randomly determined amount of dither into at least one of a flash component and a multiplying digital-to-analog converter (MDAC) in a selected channel in the ADC. A correlation procedure is performed to estimate, based on an overall ADC output, a gain experienced by the injected dither after propagating through the channel. The injection and the correlation procedure are repeated on at least one additional channel to estimate a gain for each at least one additional channel. The estimated gains of the selected channel and the at least one additional channel are then compared to determine a degree of mismatch between the selected channel and each at least one additional channel. At least one channel is calibrated as a function of the determined degree of mismatch. | 05-16-2013 |
| 20130176152 | SYSTEM AND METHOD OF ANALOG-TO-DIGITAL CONVERTERS - An analog-to-digital converter system that includes a pipeline of successively-cascaded signal converters, each operating alternatively in a first circuit configuration and a second circuit configuration, an error estimator coupled to the pipeline to receive the digitized error for estimating an amplifier gain of the present signal converter stage, and a code aligner/corrector that temporally aligns and corrects the digital codes received from the successively-cascaded signal converters to provide a digital out of the ADC system. | 07-11-2013 |
| 20140043092 | INPUT SWITCHES IN SAMPLING CIRCUITS - A switch may include a MOS transistor alternatively operating in an ON phase and an OFF phase, a first voltage level shifter, and a second voltage level shifter. The MOS transistor may include a source for receiving an input signal, a drain for connecting to a load, and a gate. The first voltage level shifter may be selectively coupled between the source and the gate during the ON phase, and the second voltage level shifter may be selectively coupled between the gate and the source during the OFF phase. | 02-13-2014 |
| 20140266844 | METHOD AND DEVICE FOR IMPROVING CONVERGENCE TIME IN CORRELATION-BASED ALGORITHMS - A method and a corresponding device reduce the convergence time of a correlation algorithm that uses random signals injected into an analog-to-digital converter (ADC) as input to the algorithm. The method and device involve, at a processor of a pipelined ADC, injecting a random signal into each of a plurality of stages in the pipeline and obtaining digital values generated in response to the random signals. Noise components of residue signals in the plurality of stages are calculated as a function of the digital values and values of the random signals. The noise components correspond to the random signals. | 09-18-2014 |
| 20150061768 | HIGH SPEED AMPLIFIER - A circuit may include one or more transistors connected directly to an output, and an inductance network. The inductance network may connect to a source node of at least one of the transistors, to compensate capacitance of the output. Thus, the response time of the circuit may decrease, and a non-dominant frequency response pole frequency of the circuit may increase. | 03-05-2015 |
| 20150061776 | HIGH SPEED AMPLIFIER - A circuit may include one or more transistors connected directly to an output, and a biasing network connected to at least one of a substrate, a well, and a back-gate of at least one of the transistors. The biasing network may biase the at least one of the substrate, the well, and the back-gate to a virtual floating bias, such that the virtual floating bias shifts in voltage level based upon an AC input signal of the circuit, to reduce the parasitic capacitance of the output node of the circuit. | 03-05-2015 |
