Analog Devices,inc.

Analog Devices International Unlimited Company

Steven C Rose

Gil Engel

Shawn S Kuo

Jialin Zhao

Hao Luo

Lin Zhang

Richard E Schreier

Matthew Louis Courcy

Donald W Paterson

Prabir C Maulik

Hassan L'Bahy

Nazmy Abaskharoun

Dong Li

Tommi Wang

Yuhu Chen

Adaptive toggle number compensation techniques for reducing data dependent supply noise in DACs are disclosed. Various embodiments are based on setting a certain target toggle number for a plurality of DAC units used to convert at least a portion of a digital data sample and then applying various adaptive techniques to try to achieve the target toggle number in converting the data sample from digital to analog domain. Adaptive toggle number compensation techniques described herein try to reduce data dependent supply noise by deliberately limiting, to a certain target number, the number of DAC units that undergo a switch from the digital input of 1 to 0 or from 0 to 1 in converting a digital data sample. Compared to the conventional dummy signal generation approach, such adaptive toggle number compensation techniques may provide significant savings in terms of power consumption of a DAC.

Adaptive toggle number compensation for reducing data dependent supply noise in digital-to-analog converters

A multi-path dual-switch DAC refers to implementing multiple paths in a switch driver and only two switches in a DAC stack of a DAC unit. In addition to multiple paths configured to improve the driving ability of the input signals, the switch driver of a multi-path dual-switch DAC unit includes two or more logic gates configured to act as multiplexers combining some of the output signals from different paths. The use of such logic gates enables using only two switches in the DAC stack unit to receive the data. Furthermore, optionally, additional logic gates may be used to combine some other output signals from different paths to generate dummy signals, thus providing internal dummy logic. The multi-path dual-switch DACs described herein may advantageously use half-clock rate and reduce or eliminate supply modulation issues, while also reducing power consumption and improving linearity compared to traditional DAC architectures.

Multi-path dual-switch digital-to-analog converter

A time-interleaved digital-to-analog converter (DAC) uses M DAC cores to convert a digital input signal whose digital input words are spread to different DAC cores to produce a final analog outputs. The M DAC cores, operating in a time-interleaved fashion, can increase the sampling rate several times compared to the sampling rate of just one DAC. However, sequential time-interleaving DAC cores often exhibit undesirable spurs at the output. To spread those spurs to the noise floor, the time-interleaving DAC cores can be selected at a pseudo randomized manner or in a specific manner which can break up the sequential or periodic manner of selecting the DAC cores.

Randomized time-interleaved digital-to-analog converters

Embodiments of the present invention may provide non-invasive techniques for adjusting timing in multistage circuit systems. A multistage circuit system according to embodiments of the present invention may include a plurality of circuit stages coupled to signal lines that carry signals. The system may also include a plurality of load circuits, one provided in for each circuit stage. The load circuits may have inputs coupled to the signal lines that carry the input signals. Each load circuit may include a current source programmable independently of the other load circuits that propagates current through an input transistor in the respective load circuit that receives the signal. The current propagating through the input transistor may provide a load on the corresponding signal line, allowing fine timing adjustment for each circuit stage.

Fine timing adjustment method

In one aspect, a calibration component configured to calibrate an automatic gain controller (AGC) for use in a tuner configured to isolate a selected channel from a multi-channel broadcast signal, the tuner implemented substantially on two chips, a first chip comprising a radio frequency (RF) integrated circuit adapted for RF processing and a second chip comprising a digital integrated circuit adapted for digital processing is provided. The calibration component comprises a calibration signal generator implemented on the RF integrated circuit, the calibration signal generator adapted to generate a generally known calibration signal, a power detector implemented on the RF integrated circuit and configured to detect, during calibration, at least one power characteristic of the calibration signal and to provide a power level signal indicative of the at least one detected power characteristic, a gain controller implemented on the digital integrated circuit, the gain controller adapted to generate at least one error signal based, at least in part, on a comparison between the power level signal provided by the power detector and a first reference signal, an offset signal generator implemented on the RF integrated circuit and configured to generate an offset signal based, at least in part, on the at least one error signal and a summing element implemented on the RF integrated circuit and adapted to combine the offset signal with the power level signal provided by the power detector to provide an adjusted power level signal.

Methods and apparatus for calibration of automatic gain control in broadcast tuners

A low-noise programmable current source includes an output digital to analog converter for providing an output load current; and a control circuit, responsive to an input defining a predetermined load current for generating, for the digital to analog converter, a control word and a control voltage; the control word and the control voltage drive the digital to analog converter to produce the predetermined load current and the control voltage sets the compliance voltage of the digital to analog converter to minimize current noise in the digital to analog converter.

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Beverly, MA, United States of America

Steven C Rose