Texas Instruments Corporation

Viswanathan Nagarajan

Visvesvaraya Appala Pentakota

Srinivas Kumar Reddy Naru

Narasimhan Rajagopal

Shagun Dusad

Neeraj Shrivastava

Nithin Gopinath

Jagannathan Venkataraman

Eeshan Miglani

Rishi Soundararajan

Ani Xavier

Roswald Francis

Sai Aditya Nurani

Charls Babu

Visvesvaraya Pentakota Appala

Harshit Moondra

Aniket Datta

Jaiganesh Balakrishnan

Jawaharlal Tangudu

Sriram Murali

Sthanunathan Ramakrishnan

Rajendrakumar Joish

Prasanth K

Chandrasekhar Sriram

Chirag Chandrahas Shetty

Himanshu Varshney

Ratna Kumar Venkata Parupudi

Ganesh Kiran

Shivam Srivastava

Karthik Khanna S

Abhinav Chandra

An analog-to-digital converter (ADC) includes: a set of comparators configured to provide comparison results based on an analog signal and respective reference thresholds for comparators of the set of comparators; digitization circuitry configured to provide a digital output code based on the comparison results and a mapping; and calibration circuitry. The calibration circuitry is configured to: receive the comparison results; determine if the analog signal is proximate to one of the respective reference thresholds based on the comparison results; in response to determining the analog signal is proximate to one of the respective reference thresholds, receive ADC values based on different pseudorandom binary sequence (PRBS) values being applied to the analog signal; determine an offset error based on the ADC values; and provide a comparator input offset calibration signal at a calibration circuitry output if the estimated offset error is greater than an offset error threshold.

Analog-to-digital converter (ADC) having selective comparator offset error tracking and related corrections

A circuit includes a nonlinear analog-to-digital converter (ADC) configured to provide a first digital output based on an analog input signal. The circuit also includes a linearization circuit having a lookup table (LUT) memory configured to store initial calibration data. The linearization circuit is coupled to the nonlinear ADC and is configured to: determine updated calibration data based on the initial calibration data; replace the initial calibration data in the LUT memory with the updated calibration data; and provide a second digital output at a linearization circuit output of the linearization circuit based on the first digital output and the updated calibration data.

Analog-to-digital converter (ADC) having linearization circuit with reconfigurable lookup table (LUT) memory and calibration options

In described examples, an analog to digital converter (ADC), having an input operable to receive an analog signal and an output operable to output a digital representation of the analog signal, includes a voltage to delay (VD) block. The VD block is coupled to the input of the ADC and generates a delay signal responsive to a calibration signal. A backend ADC is coupled to the VD block, and receives the delay signal. The backend ADC having multiple stages including a first stage. A calibration engine is coupled to the multiple stages and the VD block. The calibration engine measures an error count of the first stage and stores a delay value of the first stage for which the error count is minimum.

Calibration scheme for a non-linear ADC

In described examples, a circuit includes a calibration engine. The calibration engine generates multiple input codes. A digital to analog converter (DAC) is coupled to the calibration engine, and generates a first calibration signal in response to a first input code of the multiple input codes. An analog to digital converter (ADC) is coupled to the DAC, and generates multiple raw codes responsive to the first calibration signal. A storage circuit is coupled to the ADC and stores a first output code corresponding to the first input code. The first output code is obtained using the multiple raw codes generated by the ADC.

Calibration scheme for filling lookup table in an ADC

In described examples, a stochastic comparator includes a first comparator that compares an input signal and a primary threshold to generate a first signal. A second comparator compares the input signal and the primary threshold to generate a second signal. A decision block generates a control signal in response to the first signal, the second signal and a PRBS (pseudo random binary sequence) signal. A XOR gate generates a detection signal in response the first signal and the second signal.

Gain and memory error estimation in a pipeline analog to digital converter

A circuit for digital filtering an analog signal converted to digital, including an analog circuit to generate an analog signal, the analog signal including phase and/or gain errors. An analog-to-digital converter (ADC) to convert the analog signal to a digital signal output to a digital signal path. A frequency-dependent corrector filter included in the digital signal path, and configured as a parameterized filter, the parameterized filter configurable based on the DSA control signal with at least one complex filter parameter for each DSA attenuation step, to correct frequency-dependent errors in phase and/or gain.

Digital filtering for analog gain/phase errors

A pipeline ADC comprising an ADC segment and a digital backend coupled to the ADC segment. In some examples the ADC is configured to receive an analog signal, generate a first partial digital code representing a first sample of the analog signal, and generate a second partial digital code representing a second sample of the analog signal. In some examples the digital backend is configured to receive the first and second partial digital codes from the ADC segment, generate a combined digital code based at least partially on the first and second partial digital codes, determine a gain error of the ADC segment based at least partially on a first correlation of a PRBS with a difference between the first and second partial digital codes, and apply a first correction to the combined digital code based at least partially on the gain error of the ADC segment.

Error correcting analog-to-digital converters

In described examples, an analog to digital converter (ADC) includes a flash ADC. The flash ADC generates a flash output in response to an input signal, and an error correction block generates a known pattern. A selector block is coupled to the flash ADC and the error correction block, and generates a plurality of selected signals in response to the flash output and the known pattern. A digital to analog converter (DAC) is coupled to the selector block, and generates a coarse analog signal in response to the plurality of selected signals. A residue amplifier is coupled to the DAC, and generates a residual analog signal in response to the coarse analog signal, the input signal and an analog PRBS (pseudo random binary sequence) signal. A residual ADC generates a residual code in response to the residual analog signal.

Pattern based estimation of errors in ADC

An ADC includes a flash ADC. The flash ADC generates a flash output in response to an input signal, and an error correction block generates a known pattern. A selector block is coupled to the flash ADC and the error correction block, and generates a plurality of selected signals in response to the flash output and the known pattern. A digital to analog converter (DAC) is coupled to the selector block, and generates a coarse analog signal in response to the plurality of selected signals. A residue amplifier is coupled to the DAC, and generates a residual analog signal in response to the coarse analog signal, the input signal and an analog PRBS (pseudo random binary sequence) signal. A residual ADC generates a residual code in response to the residual analog signal.

A system includes an analog-to-digital converter (ADC) including an ADC input terminal; an ADC output terminal; and analog components configured to convert an analog signal received at the ADC input terminal to a digital signal. The system also includes a histogram estimation circuit coupled to the ADC output terminal and configured to generate information on a plurality of codes generated by the ADC and determine a region defining a range of codes corresponding to an occurrence of an error caused by the analog components of the ADC. The system also includes a dither circuit coupled to the ADC input terminal and configured to introduce a dither in the analog signal to generate a modified analog signal.

Histogram based error estimation and correction

In pipeline analog-to-digital converters (ADCs) the third harmonic can degrade the performance of the ADC, and conventional circuits that attempt to cancel this third harmonic are oftentimes sensitive to process variation, temperature variation, and common mode variations. Here a correction circuit is provided that includes a compensator that adjusts control voltages for MOS capacitors to generally ensures that the difference between the gate-source voltages and threshold voltages of MOS capacitors is generally maintained across variations of process, temperature, and common mode.

Non-linearity correction that is independent of input common mode, temperature variation, and process variation

A time-interleaved (TI) analog-to-digital converter (ADC) is provided. The TI ADC generally comprises a clock generator, two or more ADCs, adjustable delay elements, and an estimator. The clock generator generates clock signals. Each ADC is associated with at least one of the clock signals so as to sample an input signal that is generally wide-sense stationary at sampling instants, where correlation function exist between samples from a two or more of the ADCs that is a function of the time differences between associated sampling instants. The estimator is coupled to each of the adjustable delay elements and each of the ADCs so as to calculate the correlation function and adjust the adjustable delay elements to account for sampling mismatch between the ADCs based at least in part on the correlation function.

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Bengaluru, India

Viswanathan Nagarajan