Superconductor analog-to-digital converters (ADC) offer high sensitivity and large dynamic range. One approach to increasing the dynamic range further is with a subranging architecture, whereby the output of a coarse ADC is converted back to analog and subtracted from the input signal, and the residue signal fed to a fine ADC for generation of additional significant bits. This also requires a high-gain broadband linear amplifier, which is not generally available within superconductor technology. In a preferred embodiment, a distributed digital fluxon amplifier is presented, which also integrates the functions of integration, filtering, and flux subtraction. A subranging ADC design provides two ADCs connected with the fluxon amplifier and subtractor circuitry that would provide a dynamic range extension by about 30-35 dB.

A successive approximation register analog-to-digital converter includes a capacitance digital-to-analog converter (CDAC) having, a voltage storing circuit connected to an output terminal of the CDAC and including a plurality of capacitors connected in parallel, an output voltage of the CDAC being stored in a selected one of the capacitors, a selector configured to output a voltage stored in the selected one of the capacitors, a comparator configured to compare a voltage input to an input terminal thereof, which is connected to an output terminal of the CDAC, with a reference voltage, and a successive approximation register configured to control the CDAC based on an output of the comparator, and cyclically control the voltage storing circuit and the selector, such that the output of the selector is output to the output terminal one or more cycles after the output voltage was stored in the selected one of the capacitors.

A phase-locked loop (PLL) includes a spur cancellation circuit that receives a residue signal indicative of a first frequency and receives a residual phase error signal and generates a spur cancellation signal. A summing circuit combines the spur cancellation signal and a first phase error signal corresponding to a phase difference between a reference signal and a feedback signal in the PLL and generates a second phase error signal with a reduced spurious tone at the first frequency.

Certain aspects of the present disclosure provide a successive approximation register (SAR) analog-to-digital converter (ADC) implemented with a digital filter for noise shaping. For example, certain aspects provide a circuit for analog-to-digital conversion having: a first digital-to-analog converter (DAC) having an output coupled to a sampling node; a comparator having an input coupled to the sampling node; SAR logic having an input coupled to an output of the comparator and at least one output coupled to an input of the first DAC; a quantizer configured to generate a first digital signal representing a voltage at the sampling node; a digital filter configured to apply a filter to the first digital signal; and a second DAC configured to generate an analog signal representing the filtered first digital signal and provide the analog signal to the sampling node.

A time-interleaved analog to digital converter includes capacitor array circuits, at least one successive approximation register circuitry, and at least one noise shaping circuitry. The capacitor array circuits are configured to alternately sample an input signal, in order to generate a sampled input signal. The at least one successive approximation register circuitry is configured to perform an analog to digital conversion according to the sampled input signal and a residue signal, in order to generate at least one digital output. The at least one noise shaping circuitry is configured to utilize at least one first circuit in switched-capacitor circuits to transfer the residue signal from a first capacitor array circuit in the capacitor array circuits, and randomly select at least one second circuit from the switched-capacitor circuits to cooperate with a second capacitor array circuit in the capacitor array circuits to sample the input signal.

A high resolution analog to digital converter (ADC) with improved bandwidth senses an analog signal (e.g., a load current) to generate a digital signal. The ADC operates based on a load voltage produced based on charging of an element (e.g., a capacitor) by a load current and a digital to analog converter (DAC) output current (e.g., from a N-bit DAC). The ADC generates a digital output signal representative of a difference between the load voltage and a reference voltage. This digital output signal is used directly, or after digital signal processing, to operate an N-bit DAC to generate a DAC output current that tracks the load current. In addition, quantization noise is subtracted from the digital output signal thereby extending the operational bandwidth of the ADC. In certain examples, the operational bandwidth of the ADC extends up to 100s of kHz (e.g., 200-300 kHz), or even higher.

Provided is an AD converter, including: an analog signal input circuit, configured to be input with an analog input signal, and output a first analog output signal based on the analog input signal and a second analog output signal based on the analog input signal at different timing; an integral circuit, configured to integrate the first analog output signal and the second analog output signal and output the first integral signal and the second integral signal; a predictive circuit, configured to predict an integral signal output after the output by the integral circuit based on the first integral signal and the second integral signal output by the integral circuit, and output a predictive integral signal; and a quantization circuit, configured to generate a digital signal with the predictive integral signal quantized.

A high resolution analog to digital converter (ADC) with improved bandwidth senses an analog signal (e.g., a load current) to generate a digital signal. The ADC operates based on a load voltage produced based on charging of an element (e.g., a capacitor) by a load current and a digital to analog converter (DAC) output current (e.g., from a N-bit DAC). The ADC generates a digital output signal representative of a difference between the load voltage and a reference voltage. This digital output signal is used directly, or after digital signal processing, to operate an N-bit DAC to generate a DAC output current that tracks the load current. In addition, quantization noise is subtracted from the digital output signal thereby extending the operational bandwidth of the ADC. In certain examples, the operational bandwidth of the ADC extends up to 100s of kHz (e.g., 200-300 kHz), or even higher.

A noise-shaping enhanced (NSE) gated ring oscillator (GRO)-based ADC includes a delay which delays and feedbacks an error signal to an input of the NSE GRO-based ADC. The feedback error signal provides an order of noise-shaping and the error signal is generated at the input of the NSE GRO-based ADC from an input signal, the feedback error signal, and a front-end output. A voltage-to-time converter converts the error signal to the time domain. A GRO outputs phase signals from the time domain error signal by oscillating when the error signal is high and inhibiting oscillation otherwise. A quantization device quantizes the phase signals to generate the front-end output. A quantization extraction device determines a quantization error from the quantized phase signals. A time-to-digital converter digitizes the quantization error to generate a back-end output. An output device generates a second order noise-shaped output based on the front-end and the back-end outputs.

The present application discloses a successive approximation register analog-to-digital converter with passive noise shaping, which comprises: switch capacitor arrays for acquiring analog input signals; a noise shaping circuit which is a passive integral network, the network has input ends connected respectively with output ends of the two switch capacitor arrays and for acquiring output signals of the two switch capacitor arrays, is composed of a plurality of sub passive integrators, and reconfigures the plurality of sub passive integrators to different circuit forms; a comparator which has two input ends connected respectively with output ends of the passive integral network and an output end connected with an input end of a logic circuit, and is configured to compare magnitudes of the output signals of the noise shaping circuit.