The comparator includes an input unit, a load unit, a control switch, and an adjustment unit. The input ends of the input unit are connected to a first input signal and a second input signal. The load unit is connected to the input unit, and the gain of the comparator is adjusted by changing the gate voltages of the pair of gain adjustment transistors of the load unit. The adjustment unit is connected to the input unit, and the gate voltages of the pair of gain adjustment transistors are adjusted according to the enable state of the control switch. The present disclosure also provides an analog-to-digital converter.

Aspects of generating asynchronous clock signals for successive approximation register (SAR) analog to digital converters (ADCs) are disclosed. In one aspect, an asynchronous clock generator circuit is provided that is configured to receive a voltage generated by a comparator in a SAR ADC, and generate an outside-window signal in response to the voltage being outside of a voltage threshold window. The asynchronous clock generator circuit is configured to generate a trigger signal in response to the outside-window signal coinciding with the asynchronous clock signal being in an inactive state. In response to the trigger signal being in an active state for a minimum time, the asynchronous clock generator circuit is configured to generate an edge signal, and generate the asynchronous clock signal having a pulse width in response to the edge signal. The asynchronous clock generator circuit adaptively generates the asynchronous clock signal according to timing of each comparison.

An asynchronous successive approximation register analog-to-digital converter (SAR ADC), which utilizes one or more overlapping redundant bits in each digital-to-analog converter (DAC) code word, is operable to generate an indication signal that indicates completion of each comparison step and indicates that an output decision for each comparison step is valid. A timer may be initiated based on the generated indication signal. A timeout signal may be generated that preempts the indication signal and forces a preemptive decision, where the preemptive decision sets one or more remaining bits up to, but not including, the one or more overlapping redundant bits in a corresponding digital-to-analog converter code word for a current comparison step to a particular value. For example, the one or more remaining bits may be set to a value that is derived from a value of a bit that was determined in an immediately preceding decision.

A device for quantizing an analog input signal, for supply of a continuous-time output signal quantized using a plurality of bits, includes a sign analysis electronic circuit, configured to supply a first signal representative of a first sign bit of the output signal, and an envelope analysis electronic circuit, including a comparator/quantizer with two inputs one of which receives the analog input signal, configured to supply a second signal representative of at least a second bit of the output signal, as a quantized envelope signal, and a feedback loop with continuous-time digital-to-analog conversion of the quantized envelope signal, arranged between the output and the other of the two inputs of the comparator/quantizer. The quantized envelope signal is a signal of which a low pass filtering is representative of the amplitude of an envelope signal of the input signal and the feedback loop includes a low pass filter.

The exemplary embodiments relate to an asynchronously clocked successive approximation register analog-to-digital converter (SAR ADC) configured to provide a digital approximation of a sampled input signal as a result of an asynchronous successive approximation operation. The converter includes a regulation circuit configured to determine whether the asynchronous successive approximation operation was performed within a predefined conversion time and to regulate the SAR ADC such that the conversion time of the asynchronous operation is shifted towards the predefined conversion time. The embodiments further relate to a corresponding method and a corresponding design structure.

Systems and methods are provided for a successive approximation register (SAR) analog-to-digital converter (ADC) with an ultra-low burst error rate. Analog-to-digital conversions may be applied via a plurality of successive conversion cycles, with each conversion cycle corresponding to a particular bit in a corresponding digital output. Meta-stability may be detected during each one of the plurality of successive conversion cycles, and for each one of the plurality of successive conversion cycles, a next one of the plurality of successive conversion cycles may be triggered based on a cycle termination event. After completion of all of the plurality of successive conversion cycles, a meta-stability state of each of the plurality of successive conversion cycles may be assessed, and the digital output may be controlled based on the assessment.

A successive approximation register (SAR) analog-to-digital converter (ADC) includes a ring oscillator configured to determine a frequency based on a sampling clock signal and a first control code, and generate an output clock signal having the determined frequency. The SAR ADC further includes a controller configured to generate the first control code based on a count value indicating a number of times of toggling the output clock signal.

In some examples, a method includes applying a bias voltage to a resolver system. The method also includes receiving a sensed signal, the sensed signal varying in value based on a position of a rotary element. The method also includes attenuating the sensed signal to form an attenuated signal. The method also includes performing fault detection on the attenuated signal to detect faults in the resolver system. The method also includes processing the attenuated signal to determine the position of the rotary element.

A self-clocked SAR ADC sensor circuit includes an ADC having a capacitor array with a plurality of capacitors connected through a respective plurality of switches, a comparator, an SAR module, and a delay element circuit for ring oscillator and stall detection. The delay element circuit includes a delay block with a NAND gate followed by a plurality of inverters.

In one aspect, an apparatus includes: a first feedback digital-to-analog converter (DAC) to receive a first feedback signal from a first successive approximation register (SAR) and output a first analog signal; a comparator to compare the first analog signal with a reference voltage; the first SAR to store a digital value based on the comparison and provide the first feedback signal to the first DAC; a second feedback DAC to receive a modulated quantized residual error based on the comparison and output a second analog signal; a second SAR to store a quantized residual error; and a delta-sigma modulator (DSM) to modulate the quantized residual error and provide the modulated quantized residual error to the second feedback DAC.