A DWA circuit includes: a thermometer conversion unit configured to convert an input digital signal into a thermometer code; a shift amount storage unit configured to store a shift amount; a shift unit configured to cyclically shift the thermometer code; an arrangement conversion unit configured to supply, to an analog output circuit, an output control code obtained by converting a bit arrangement of a shifted code; and an update unit configured to update the shift amount, in which the shifted code includes a plurality of unconverted bit fields, the output control code includes a plurality of converted bit fields, and the arrangement conversion unit is configured to perform arrangement conversions on a plurality of bits having a same position in a bit field in the plurality of unconverted bit fields, to arrange the plurality of bits in a same converted bit field among the plurality of converted bit fields.

An automatic frequency calibration and lock detection circuit includes a frequency error generator circuit, an automatic frequency calibration signal generator circuit, and a lock flag generator circuit. The frequency error generator circuit generates a frequency error signal based on a reference frequency signal and an output frequency signal. The frequency error signal represents a difference between a frequency of the output frequency signal and a target frequency. The automatic frequency calibration signal generator circuit generates an automatic frequency calibration output signal and an automatic frequency calibration done signal based on the frequency error signal and a first clock signal. The lock flag generator circuit generates a lock done signal based on the frequency error signal, the automatic frequency calibration done signal and a second clock signal. The frequency error generator circuit is shared by the automatic frequency calibration signal generator circuit and the lock flag generator circuit.

Methods and digital circuits providing frequency correction to frequency synthesizers are disclosed. An FLL digital circuit is provided that is configured to handle a reference frequency that is dynamic and ranges over a multi-decade range of frequencies. The FLL circuit includes a digital frequency iteration engine that allows for detection of disappearance of a reference frequency. When the digital frequency iteration engine detects that the reference frequency signal is not available, the oscillator generated frequency is not corrected, and the last value of the oscillator generated frequency is held until the reference frequency signal becomes available again. This FLL circuit is also preceded by a low-pass filter which is dynamically tuned to the frequency to which the FLL locks, eliminating harmonic components in the original signal which might otherwise cause errors in frequency estimation.

Methods and digital circuits providing frequency correction to frequency synthesizers are disclosed. An FLL digital circuit is provided that is configured to handle a reference frequency that is dynamic and ranges over a multi-decade range of frequencies. The FLL circuit includes a digital frequency iteration engine that allows for detection of disappearance of a reference frequency. When the digital frequency iteration engine detects that the reference frequency signal is not available, the oscillator generated frequency is not corrected, and the last value of the oscillator generated frequency is held until the reference frequency signal becomes available again. This FLL circuit is also preceded by a low-pass filter which is dynamically tuned to the frequency to which the FLL locks, eliminating harmonic components in the original signal which might otherwise cause errors in frequency estimation.

A readout circuit for use in an image sensor includes a plurality of comparators. Each one of the plurality of comparators is coupled to receive a ramp signal and a respective analog image data signal from a respective one of a plurality of column bit lines to generate a respective comparator output. Each one of a plurality of arithmetic logic units (ALUs) is coupled to receive phase-aligned Gray code (GC) outputs generated by a GC generator. Each one of the plurality of ALUs is further coupled to a respective one of the plurality of comparators to receive the respective comparator output. Each one of the plurality of ALUs is coupled to latch the phase-aligned GC outputs in response to the respective comparator output to generate a respective digital image data signal.

A readout circuit for use in an image sensor includes a plurality of comparators. Each one of the plurality of comparators is coupled to receive a ramp signal and a respective analog image data signal from a respective one of a plurality of column bit lines to generate a respective comparator output. Each one of a plurality of arithmetic logic units (ALUs) is coupled to receive phase-aligned Gray code (GC) outputs generated by a GC generator. Each one of the plurality of ALUs is further coupled to a respective one of the plurality of comparators to receive the respective comparator output. Each one of the plurality of ALUs is coupled to latch the phase-aligned GC outputs in response to the respective comparator output to generate a respective digital image data signal.

Apparatuses, systems and methods associated with bidirectional Gray code counter design are disclosed herein. In embodiments, a bidirectional Gray code counter may include a sequential logic element to store a Gray code value and logic circuitry. The logic circuitry may be to determine, based on a bidirectional indicator signal, whether to increment or decrement the Gray code value update, through performance of an increment or a decrement of the Gray code value based on the determination of whether to increment or decrement the Gray code value, the Gray code value to be a sequential Gray code value and replace the Gray code value stored in the sequential logic element with the updated Gray code value. Other embodiments may be described and/or claimed.

An analog to digital converter is provided. The analog to digital converter includes: an arithmetic operator combining an analog input signal with a feedback signal; a loop filter filtering an output signal of the arithmetic operator; a quantizer quantizing an output signal of the loop filter to output a digital signal; and a feedback converting the digital signal to output a feedback signal, in which the quantizer includes: a plurality of VCOs each receiving a positive output signal and a negative output signal of the loop filter and outputting VCO signals; a plurality of samplers receiving the VCO signals output from the plurality of VCOs, respectively and outputting sampled signals; and a phase detector detecting a phase difference in the sampled signals output from the plurality of samplers, respectively, to detect a phase difference in two VCO signals output from the plurality of VCOs, respectively.

A reconfigurable, digital phase-locked loop integrated circuit is disclosed which is coupleable to a reference frequency generator. A representative embodiment may include a memory storing a plurality of configuration parameters, at least one configuration parameter of specifying an output frequency; a reconfigurable frequency and delay generator configurable and reconfigurable in response to the configuration parameters to generate an output signal having the output frequency; and a digital controller adapted to access the memory and retrieve the plurality of configuration parameters, and to generate a plurality of control signals to the reconfigurable frequency and delay generator both to generate the output signal having the output frequency in response to the plurality of configuration parameters, and to match a phase of the output signal to an input signal phase.

A reconfigurable, digital phase-locked loop integrated circuit is disclosed which is coupleable to a reference frequency generator. A representative embodiment may include a memory storing a plurality of configuration parameters, at least one configuration parameter of specifying an output frequency; a reconfigurable frequency and delay generator configurable and reconfigurable in response to the configuration parameters to generate an output signal having the output frequency; and a digital controller adapted to access the memory and retrieve the plurality of configuration parameters, and to generate a plurality of control signals to the reconfigurable frequency and delay generator both to generate the output signal having the output frequency in response to the plurality of configuration parameters, and to match a phase of the output signal to an input signal phase.