A system includes a first circuit configured to provide a digitally pre-distorted input signal, a digital-to-analog converter including a number of unit elements, a digital input, and a digital output. Each unit element is configured to receive a reference voltage and to be controllable by a control signal provided in response to the digitally pre-distorted input signal. The digital-to-analog converter provides an analog output. The first circuit is configured to reduce distortion due to signal dependent changes to the reference voltage. The signal dependent changes can be due at least in part to current through the supply network that supplies the reference voltage. The digital to analog converter can be a voltage mode converter.

Disclosed examples include a segmented DAC circuit, including an R-2R resistor DAC to convert a first subword to a first analog output signal, an interpolation DAC to offset the first analog output signal based on an N-bit digital interpolation code signal to provide the analog output signal, and a Sigma Delta modulator to modulate a modulator code to provide the N-bit digital interpolation code signal that represents a value of second and third subwords.

A digital-to-analog converter (DAC) includes a plurality of resistive elements connected together in series to form a ring of resistive elements. A node is formed by each of the connections of adjacent resistive elements of the ring. Groups of parallel-connected switches are coupled to each node. A first switch of the group of switches is for selectively coupling a first power supply voltage terminal to the node. A second switch of the group of switches is for selectively coupling a second power supply voltage to the node. A third switch of the group of switches is for selectively coupling an output terminal to the node. A differential or single-ended analog output may be provided. Mismatch induced error is removed using a mismatch error shaping technique that shapes the errors outside a pass-band.

A delta-sigma modulator includes a receiving circuit, a loop filter, a quantizer, a dynamic element matching circuit and a digital to analog converter. The receiving circuit is arranged for receiving a feedback signal and an input signal to generate a summation signal. The loop filter is arranged for receiving the summation signal to generate a filtered summation signal. The quantizer is arranged for generating a digital output signal according to the filtered summation signal. The dynamic element matching circuit is arranged for receiving the digital output signal to generate a shaped digital output signal for shaping element mismatch. The digital to analog converter is arranged for performing a digital to analog converting operation upon a signal derived from the shaped digital output signal to generate the feedback signal to the receiving circuit, wherein clock signals used by the quantizer and the dynamic element matching circuit have different frequencies.

A circuit device includes a control circuit having a successive approximation register, a D/A conversion circuit adapted to perform D/A conversion on output data from the successive approximation register, and a comparison circuit adapted to compare an analog input signal and an output signal from the D/A conversion circuit with each other, the control circuit includes an upper limit value register and a lower limit value register adapted to respectively hold an upper limit value and a lower limit value of a conversion range, and increases the upper limit value or decreases the lower limit value in the case in which the same comparison result has been output by the comparison circuit a predetermined number of times or more.

Systems and methods are provided for digital-to-analog converters (DACs) with enhanced dynamic element matching (DEM) and calibration. DEM may be adapted based on assessment of one or more conditions that may affect the DACs or DEM functions thereof. The one or more condition may comprise amount of signal backoff. The adaption may comprise switching the DEM function (as a whole, or partiallye.g., individual DEM elements) on or off based on the assess conditions. The DACs may incorporate use of calibration. The DEM and/or the calibration may be applied to only a portion of the DAC, such as a particular segment (e.g., a middle segment comprising bits between the MSBs and the LSBs).

Methods and systems are provided for using localized dynamic element matching (DEM) and/or dynamic noise scaling (DNS) in digital-to-analog converters (DACs). Adaptive (localized) DEM may be applied in a DAC, by selecting one or more of a plurality DAC elements in the DAC, forcing the selected one or more of the plurality of DAC elements not to switch during digital-to-analog conversions, and scrambling remaining one or more of plurality of DAC elements when generating an output of the DAC. The adaptive DEM may be applied when the DAC input is backed off from full-scale. DNS may be applied in a DAC, by adaptively selecting one or more of a plurality DAC elements in the DAC and switching off the selected one or more of the plurality DAC elements such that the selected one or more of the plurality DAC elements do not contribute to generating an output of the DAC.

An analog-to-digital converter (ADC) is a device that can include a reference shuffler and a loop filter. An ADC can achieve better performance with incremental adjustment of a pointer of the reference shuffler, changing coefficients of the loop filter, and storing calibration codes of the ADC in a non-volatile memory. By incrementally adjusting a pointer of the reference shuffler, a calibration can be performed more efficiently than with a random adjustment of the pointer. By temporarily changing the loop filter coefficients, a greater amount of activity can be introduced into the loop filter. This activity can allow the calibration to proceed more efficiently. By storing the calibration codes in a non-volatile memory, a search space for calibration codes can be reduced. Thus, a calibration can occur more quickly, and the calibration itself can be improved.

A delta-sigma modulator includes a receiving circuit, a loop filter, a quantizer, a dynamic element matching circuit and a digital to analog converter. The receiving circuit is arranged for receiving a feedback signal and an input signal to generate a summation signal. The loop filter is arranged for receiving the summation signal to generate a filtered summation signal. The quantizer is arranged for generating a digital output signal according to the filtered summation signal. The dynamic element matching circuit is arranged for receiving the digital output signal to generate a shaped digital output signal for shaping element mismatch. The digital to analog converter is arranged for performing a digital to analog converting operation upon a signal derived from the shaped digital output signal to generate the feedback signal to the receiving circuit, wherein clock signals used by the quantizer and the dynamic element matching circuit have different frequencies.

A circuit device includes a control circuit having a successive approximation register, a D/A conversion circuit adapted to perform D/A conversion on output data from the successive approximation register, and a comparison circuit adapted to compare an analog input signal and an output signal from the D/A conversion circuit with each other, the control circuit includes an upper limit value register and a lower limit value register adapted to respectively hold an upper limit value and a lower limit value of a conversion range, and increases the upper limit value or decreases the lower limit value in the case in which the same comparison result has been output by the comparison circuit a predetermined number of times or more.