A multi-bit resolution sub-pipeline structure for measuring a jump magnitude of a transmission curve, comprising: a sub-analog-to-digital converter having n-bit resolution configured to quantize input analog voltage signals and output digital voltage signals; a sub-digital-to-analog converter having n-bit resolution configured to convert the digital voltage signals output by the sub-analog-to-digital converter into corresponding analog voltage signals; a decoder having n-bit resolution configured to decode an n-bit binary input signal; and a switched-capacitor amplification unit configured to, when in a normal mode, perform sampling and residue amplification on the input analog voltage signals; and when in a test mode, measure the jump magnitude of the transmission curve corresponding to each decision level. Magnitude measurement of a transmission curve is performed within 2.sup.n clock periods, th and a measurement result is sent to a back-end digital domain of the A/D converter for correction.

Example embodiments relate to systems and methods for analog-to-digital signal conversion. One embodiment includes a system for analog-to-digital signal conversion. The system includes an analog input signal. The system also includes a digital-to-analog converter configured to generate a reference signal. Further, the system includes an amplifier configured to amplify an error signal that includes a difference between the analog input signal and the reference signal. Additionally, the system includes a level-crossing based sampling circuit that includes a first comparator configured to compare the error signal with respect to a first reference level, and a second comparator configured to compare the error signal with respect to a second reference level, thereby generating event-based reset signals corresponding to a plurality of sampling instances in order to reset the digital-to-analog converter. Yet further, the system includes a trigger circuit configured to generate reset signals asynchronous to the event-based reset signals.

An analog-to-digital converter (ADC) is described. This ADC includes a conversion circuit with multiple bit-conversion circuits. During operation, the ADC may receive an input signal. Then, the conversion circuit may asynchronously perform successive-approximation-register (SAR) analog-to-digital conversion of the input signal using the bit-conversion circuits, where the bit-conversion circuits to provide a quantized representation of the input signal. For example, the bit-conversion circuits may asynchronously and sequentially perform the SAR analog-to-digital conversion to determine different bits in the quantized representation of the input signal. Moreover, the ADC may selectively perform self-calibration of a global delay of the bit-conversions circuits. Note that the timing self-calibration may be iterative and subject to a constraint that a maximum conversion time is less than a target conversion time.

The present disclosure enables firmware-based interleaved-ADC gain calibration and provides hardware-thresholding enhancements. An on-chip memory may store subADC samples and a microprocessor accesses these stored samples for use with the calibration algorithm. Power estimates may be performed using square of each subADC sample to estimate gain error. Thresholding may be applied to the subADC samples, such as Maximum Amplitude Thresholding, Minimum Power Thresholding, and/or using Histogram Output Memory, to determine that samples are valid and may be used for calibration or that subADC data are to be discarded and a new subADC data capture is to be started.

A clock product includes a time-to-digital converter responsive to an input clock signal, a reference clock signal, and a time-to-digital converter calibration signal. The time-to-digital converter includes a coarse time-to-digital converter and a fine time-to digital converter. The clock product includes a calibration circuit including a phase-locked loop. The calibration circuit is configured to generate the time-to-digital converter calibration signal. The clock product includes a controller configured to execute instructions that cause the phase-locked loop to generate an error signal for each possible value of a fine time code of a digital time code generated by the time-to-digital converter and to average the error signal over multiple clock cycles to generate an average error signal.

A metastable state detection device and method, and an ADC circuit are disclosed. The metastable state detection device includes: a delay unit which is configured to receive a synchronization signal and delay the synchronization signal based on preset step delay values; a first flip-flop unit including a first clock input terminal, a first data input terminal and a first data output terminal, wherein the first clock input terminal is configured to receive a clock signal; the first data input terminal is configured to receive the delayed synchronization signal; a second flip-flop unit including a second clock input terminal, a second data input terminal and a second data output terminal; a processing module connected to the second data output terminal, which is configured to receive a target clock signal and detect a metastable state of the first flip-flop unit according to the target clock signal.

A residue transfer loop, a successive approximation register analog-to-digital converter and a gain calibration method are disclosed. In particular, the residue transfer loop includes a sampling switch module, a logic controlling circuit, a residue holding capacitor module, a DAC capacitor array, a residue transfer module, a current rudder, a reset switch module and a charge sharing switch module. The logic controlling circuit sequentially outputs control signals according to preset time intervals in a preset period to control the reset switch module, the residue transfer module, the sampling switch module and the charge sharing switch module to work sequentially, thereby realizing a residue transfer.

An image sensor includes ADCs, each including a comparator receiving a ramp signal and an image signal, and generating a comparator output. Each ADC also includes a counter ceasing to change a digital count value in response to a change in the comparator output. The digital count value has a first resolution. Each ADC also includes a delay line circuit including a delay line generating a first digital value encoding a duration of a period of the counter clock and generating a second digital value encoding a first portion of the period of the counter clock. Each ADC also includes a delay to digital circuit generating a digital output value based on the first and digital values. The digital output value encodes a second value of the ramp signal, where the digital count value has a second resolution that is greater than the first resolution.

In at least one embodiment, a method includes generating a digital time code corresponding to an input clock signal using a time-to-digital converter responsive to a reference clock signal and a time-to-digital converter calibration signal. The method includes generating the time-to-digital converter calibration signal based on the digital time code. Generating the time-to-digital converter calibration signal includes generating a digital error signal based on the digital time code and an estimated digital time code, and adapting the time-to-digital converter calibration signal based on the digital error signal.

An analog-to-digital conversion device and analog-to-digital conversion method thereof are provided. The analog-to-digital conversion device includes an analog circuit configured to output an analog input signal, and an analog-to-digital converter configured to receive the analog input signal and configured to outputting a digital output signal corresponding to the analog input signal with the use of first and second capacitor arrays, each of the first and second capacitor arrays including a first capacitor having a calibration capacitor connected thereto and a second capacitor having no calibration capacitor connected thereto, wherein the analog-to-digital converter is configured to calibrate the capacitance of the first capacitor by providing a first calibration voltage to the calibration capacitor and is configured to output the digital output signal corresponding to the analog input signal with the use of the calibrated capacitance of the first capacitor.