Cirrus Logic Inc.

Rajendra Datar

Krishnan Subramoniam

Manoj Shridhar Soman

Dylan Alexander Hester

Sachin P Ghanekar

Anand Venkitachalam

John L Melanson

Joe Welser

Hua Hong

Sebastian Gracias

Anad Venkitachalam

Brian Frank Bounds

Ravindra Gogte

A gain or input volume controller and method includes a modified R2R ladder network having a number of R2R branches, switches coupled respectively to the R2R branches, and a switch controller for respectively controlling the switches to control and provide an overall gain value for a signal. The switch controller further includes a mapper for mapping a gain control signal to the switches wherein the gain control signal respectively activates or deactivates the switches. A fine gain control stage provides a fine gain control of the overall gain value. A coarse gain control stage is coupled to the fine gain control stage. The coarse gain control stage includes the modified R2R ladder network and provides a coarse gain control of the overall gain value.

Gain or input volume controller and method utilizing a modified R2R ladder network

A current steering digital to analog converter includes a current source for selectively providing a selected amount of current to an output in response to input data. The current source includes a selected number of sub-current sources for selectively providing fractions of the selected amount of current to the output. Compensation current sources each provide a selected amount of compensation current to the output. Compensation control circuitry, in response to the input data, selectively activates and de-activates selected ones of the sub-current sources and the compensation current sources to provide current compensation at the output.

Current steering digital to analog converters with self-calibration, and systems and methods using the same

A method of detecting frequency errors exceeding a predetermined limit in a sampled signal includes the step of determining a peak amplitude of the signal at a tone frequency for a first frame of samples of the sampled signals using a filter having a first amplitude versus frequency response. A peak amplitude of signal at the tone frequency is determined for a second frame of samples of the sampled signal using a filter having a second amplitude versus frequency response. A ratio between the peak amplitude of the first frame and the peak amplitude of the second frame is calculated and compared against a threshold to detect frequency errors exceeding the predetermined limit. Among other things, this method decouples the frequency error detection problem from the twist factor estimation problem.

Frequency error detection methods and systems using the same

A method of performing sample rate conversion in a data converter operating from an oversampling clock corresponding to a native sample rate and a native oversampling factor. A virtual sample rate and a virtual oversampling factor are selected proportional to the native sample rate and the native oversampling factor. A data stream having a data sample rate is sampled by the virtual oversampling factor. The data stream is also resampled with a resampling ratio approximating a ratio of the data sample rate to the virtual sample rate.

Sample rate converters using virtual sample rates and analog to digital and digital to analog converters using the same

An integrated circuit included a plurality of circuit blocks for selectively performing data processing operations in response to a set of instructions. Circuitry dynamically activates and deactivates selected ones of circuit blocks during the execution of the set of instructions.

Dynamically activating and deactivating selected circuit blocks of a data processing integrated circuit during execution of instructions according to power code bits appended to selected instructions

A sample rate converter for converting a data stream having a first base sampling frequency to a data stream having a second base sampling frequency. Up-sampling circuitry receives first oversampled data having a first oversampling ratio with respects to the first base frequency and outputs second oversampled data having a second oversampling ratio with respects to the first base sampling frequency. Resampling circuitry resamples the second oversampled data by a resampling frequency ratio of integers representing a ratio of the first and second base frequencies and generates third oversampled data having the second oversampling ratio with respects to the second base frequency. Down-sampling circuitry then down-samples the third oversampled data and generates fourth oversampled data having the first oversampling ratio with respects to the second base frequency.

Sample rate converters with minimal conversion error and analog to digital and digital to analog converters using the same

A sample rate converter includes a filter for processing digital data in response to a clock controlled by a clock enable signal, the filter receiving the digital data at a first sampling rate and outputting digital data at a second sampling rate. Resampler circuitry generates first selected periods of the clock enable signal having a first duty cycle approximating a ratio between the first sampling rate and the second sampling rate. Selectively, selected periods of the clock enable signal are generated having a second duty cycle for minimizing an error accumulated over the first selected periods of the clock enable signal.

Variable duty cycle resampling circuits and methods and sample rate converters using the same

A current mirror,includes a current mirroring transistor,having a selected aspect ratio for conducting a mirrored current of a selected mirroring ratio with respect to a reference current. A plurality of reference current transistors,are disposed in parallel with current mirroring transistor,, each of the reference current transistors,having a current path coupled to a source,of the reference current and a selected aspect ratio. A switch,is coupled to a control terminal of a selected reference current transistor,, for selectively turning on and turning off a selected reference current transistor,to adjust the mirroring ratio.

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Pune, India

Rajendra Datar