An imaging system may include an image sensor. The image sensor may have an array of image pixels arranged in rows and columns. Each column of image pixels may be coupled to column readout circuitry via a corresponding column line. The column readout circuitry may include analog-to-digital conversion circuitry. The analog-to-digital conversion circuitry may include split MSB and LSB capacitor banks. The MSB capacitor bank may include capacitors selectively coupled to a coarse reference voltage or a fine reference voltage. The LSB capacitor bank may include capacitors electively coupled to the coarse reference voltage.

Methods and devices are described for controlling excess loop delay (ELD) gain compensation in a digital-to-analog converter (DAC) of a successive approximation register (SAR) analog-to-digital converter (ADC) by using DAC unit elements in the ELD DAC and DACs for the SAR ADC efficiently. The ELD DAC and DAC partially share DAC units (e.g. capacitors or current sources) to minimize total DAC units used to limit area and power usage while maintaining operational flexibility. Different configurations provide ELD gains of less than or greater than one. A dedicated sampling capacitor is also provided to allow flexible gain control by capacitance ratio.

A capacitive analog-to-digital converter, an analog-to-digital conversion system, a chip, and a device. The capacitive analog-to-digital converter includes: a first capacitor array, including N first capacitor banks that include M first capacitors, where M is a positive integer greater than N; M first switches, respectively connected to first electrode plates of the M first capacitors in a one-to-one correspondence to enable a successive approximation logic controller to control connections of the first electrode plates of the M first capacitors with an output of a voltage generation circuit and with a first sampling voltage output by controlling the M first switches; a comparator, including a first input, a second input and an output; and the successive approximation logic controller, connected to the output of the comparator, and configured to control the M first switches according to comparison results output by the output of the comparator.

The present disclosure relates to a capacitor array for an analog-to-digital converter, a successive approximation register analog-to-digital converter and a capacitor array board. The capacitor array includes a control logic generation circuit, a control code logic conversion circuit, a first sub-capacitor array and a second sub-capacitor array configured to form different regions of a high-order bit region and a low-order bit region. In the present disclosure, the capacitances of the second capacitor units are equal, so that the second capacitor units can be sequentially switched. Thus, no matter which bit in the second binary code changes, it will not cause a large number of the second capacitor units to switch together, thereby reducing conversion error. In addition, the capacitor array is divided in regions, which avoids the problem of a large number of parallel branches in case where only the second sub-capacitor array is arranged.

An analog-to-digital converter (ADC) includes a capacitive digital-to-analog converter (CDAC), a comparator coupled to the CDAC, and a successive approximation register (SAR) control circuit coupled to the CDAC and the comparator. The SAR control circuit is configured to successively select bits of a digital output value. The SAR control circuit is also configured to, after selection of the bits of the digital output value: maintain a state of first switches of the CDAC applied to select a most significant bit of the digital output value, and revert second switches of the CDAC applied to select bits of the digital output value having significance lower than the most significant bit to a state of the second switches prior to selection of the most significant bit.

Techniques are described to cancel kT/C sampling noise and residue amplifier sampling noise while also reducing power consumption in a pipelined analog-to-digital converter circuit.

Circuits for continuous-time analog correlators are provided, comprising: a first VCO that receives an input signal and that outputs a first pulse frequency modulated (PFM) output signal; a second VCO that receives a reference signal and that outputs a second PFM output signal; a first phase frequency detector (PFD) that receives the first PFM output signal and the second PFM output signal and that produces a first PFD output signal; a first delay cell that receives the first PFM output signal and that produces a first delayed signal (DS); a second delay cell that receives the second PFM output signal and that produces a second DS; a second PFD that receives the first DS and the second DS and that produces a second PFD output signal; and a capacitor-digital-to-analog converter (capacitor-DAC) that receives the first PFD output signal and the second PFD output signal and that produces a correlator output.

A calibratable switched-capacitor voltage reference and an associated calibration method are described. The voltage reference includes dynamic diode elements providing diode voltages, input capacitor(s) for sampling input voltages, base-emitter capacitor(s) for sampling one diode voltage with respect to a ground, dynamically trimmable capacitor(s) for sampling the one diode voltage with respect to another diode voltage, and an operational amplifier coupled to the capacitors for providing reference voltage(s) based on the sampled input and diode voltages and on trims of the trimmable capacitor(s). The voltage reference can be configured as a first integrator of a modulator stage of a delta-sigma analog-to-digital converter.

An electronic circuit comprises capacitive structures that are connected to one or a plurality of nodes, where each of the capacitive structures is formed by a capacitor or by a plurality of capacitors electrically connected in parallel. The electronic circuit further comprises additional capacitors that are each connected to the one or plurality of nodes. For at least one distance between capacitors, the capacitive structures have a same average of values defined, for each capacitor of each capacitive structure, by the number of capacitors of the circuit connected to the one or plurality of nodes and located at the distance from the capacitor of the capacitive structure.

A delta-sigma modulator generates a bit stream signal from an analog signal by operating according to a modulation period including a sampling period and a filtering period and includes a digital-to-analog converter (DAC) configured to generate a charge signal according to one of a first reference voltage and a second reference voltage according to the bit stream signal during the sampling period and to output a signal generated according to the charge signal and the other of the first reference voltage and the second reference voltage; a loop filter configured to charge a sampling signal corresponding to the analog signal during the sampling period and to filter an output from the DAC and a signal generated according to the sampling signal during the filtering period; and a quantizer configured to generate the bit stream signal according to an output from the loop filter in the modulation period.