Nxp Usa, Inc.

Freescale Semiconductor,inc.

Mark Lancaster

George Rogers Kunnen

Brandt Braswell

Chongli Wu

Michael E Stanley

George R Kunnen

Time-interleaved analog-to-digital converters (ADCs) and related methods are disclosed that are based upon multiplying digital-to-analog converters (MDACs). For one ADC embodiment, a sample-and-hold circuit receives an input signal and outputs a voltage that represents the input signal. An MDAC receives the voltage, outputs an N-bit digital value, and outputs a current that represents the voltage. A phased current generator receives the current and outputs time-interleaved currents that are based upon the current. An array of sub-ADCs receive the time-interleaved currents, and each sub-ADC outputs a digital value. The digital values from the array of sub-ADCs are then combined and to output an M-bit digital value. The N-bit digital value and the M-bit digital value provide a digital conversion output for the ADC.

MDAC based time-interleaved analog-to-digital converters and related methods

Current controlled multiplying digital-to-analog converters (MDACs) and related methods are disclosed for time-interleaved analog-to-digital converters (ADCs). For one embodiment, a circuit includes an MDAC having an amplifier that converts a voltage to an output current, a variable load that is dependent upon a digital value and that controls the output current from the amplifier, and an array of comparators that receive the voltage and output the digital value to the variable load. The digital value represents at least a portion of a digital conversion of the voltage. Further, the circuit can include a phased current generator that receives the output current and generates time-interleaved currents where each time-interleaved current is a sampled copy of the output current.

Current controlled MDAC for time-interleaved ADCS and related methods

Digital calibration systems and related methods are disclosed for multi-stage analog-to-digital converters (ADCs). For one embodiment, a multi-stage ADC includes an initial ADC, an additional ADC, and calibration logic. The initial ADC generates an output signal and N-bit digital values that are based upon an input signal. The additional ADC receives the output signal from the initial ADC and generates M-bit digital values that are based upon the output signal. The calibration logic receives the N-bit digital values and the M-bit digital values and generates correction values. The correction values are based upon differences between maximum values and minimum values for M-bit digital values associated with different regions determined by the N-bit digital values. Digital conversion outputs for the multi-stage ADC are provided as combinations of the N-bit digital values and the M-bit digital values corrected with the correction values.

Digital calibration systems and methods for multi-stage analog-to-digital converters

The embodiments described herein provide analog-to-digital converters (ADCs) and systems and methods for calibrating ADCs, including ADCs with poorly characterized nonlinearities that cannot be effectively calibrated with traditional calibration techniques. In general, the embodiments described herein calibrate by measuring output values from an ADC with a known calibration input values being applied. The measured output values are used to determine localized polynomial interpolants. Each of the determined localized polynomial interpolants is then evaluated at an uncorrected output value, and the evaluated localized polynomial interpolants are then used to generate correction values. These correction values can then be used to calibrate the ADC during later operation. Such a calibration technique can provide effective calibration for a variety of ADCs, including ADCs that use inverter-based voltage-to-current (VI) converters and current-controlled ring oscillators.

Analog-to-digital conversion with linearity calibration

The embodiments described herein provide calibration systems and methods for mixed-signal devices. Specifically, the embodiments provide systems and methods for calibrating mixed-signal devices that can facilitate effective calibration of such mixed-signal devices, including mixed-signal devices with poorly characterized nonlinearities that cannot be effectively calibrated with traditional calibration techniques. In general, the embodiments described herein calibrate by measuring output values from a mixed-signal device with a known calibration input values being applied. The measured output values are used to determine localized polynomial interpolants. Each of the determined localized polynomial interpolants is then evaluated at an uncorrected output value, and the evaluated localized polynomial interpolants are then used to generate correction values.

System and method for linearity calibration in mixed-signal devices

A system includes an analog-to-digital converter (ADC) for converting an analog input signal to a digital signal output and a nonlinearity corrector for correcting nonlinear error in the digital signal output to produce a corrected digital signal output. A source of the nonlinear error is associated with the ADC, wherein an analog calibration signal is introduced to the source of the nonlinear error during conversion of the analog calibration signal to a digital calibration output having the nonlinear error. After conversion of the analog calibration signal to the digital calibration output, a calibration circuit calculates expected values of correlation sums in response to the digital calibration output and determines correction coefficients using the expected values of the correlation sums. The calibration circuit provides correction data based upon the correction coefficients to the nonlinearity corrector.

Analog-to-digital converter with expected value nonlinearity calibration

A system and method are present for generating a modulated waveform. A timer is configured to generate a first modulated waveform signal, and an adder module is configured to calculate a delay. The delay includes at least one of an edge fractional delay and a dead time fractional delay. A delay module is operably coupled to the timer and the adder module. The delay module is configured to delay at least one of a rising edge of the first modulated waveform signal and a falling edge of the first modulated waveform signal by the delay to generate a second modulated waveform signal that has a higher frequency resolution than a frequency resolution of the first modulated waveform signal.

Methods and apparatus for generating a modulated waveform

Apparatus and methods are provided for performing a sampling sequence for a plurality of samples. An analog-to-digital conversion module comprises a sampling module, a register, and a sampling control module coupled to the sampling module and the register. The sampling module is configured to convert analog signals into corresponding digital values in response to sampling trigger signals and the register is configured to maintain scan mode criteria for a plurality of samples. The sampling control module is configured to identify a scan mode criterion for a respective sample of the plurality of samples, automatically generate a sampling trigger signal when the scan mode criterion for the respective sample is equal to a first value, and generate the sampling trigger signal in response to a timing trigger signal when the scan mode criterion for the respective sample is equal to a second value.

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Scottsdale, AZ, United States of America

Mark Lancaster