A quantizer for a sigma-delta modulator, a sigma-delta modulator, and a method of shaping noise are provided. The quantizer includes: an integrator configured to generate, in a K.sup.th sampling period, a quantization error signal for a K.sup.th period according to an internal signal, a quantization error signal for a (K−1).sup.th period, a filtered quantization error signal for the (K−1).sup.th period and a filtered quantization error signal for a (K−2).sup.th period; an integrating capacitor configured to store the quantization error signal for the K.sup.th period, to weight the internal signal in a (K+1).sup.th sampling period; a passive low-pass filter configured to acquire the quantization error signal for the K.sup.th period in a K.sup.th discharge period, and feed back the filtered quantization error signal to the integrator in a (K+1).sup.th sampling period and a (K+2).sup.th sampling period; and a comparator configured to quantize the quantization error signal for the K.sup.th period.

Herein disclosed are some examples of metastability detectors and compensator circuitry for successive-approximation-register (SAR) analog-to-digital converters (ADCs) within delta sigma modulator (DSM) loops. A metastability detector may detect metastability at an output of a SAR ADC and compensator circuitry may implement a compensation scheme to compensate for the metastability. The identification of the metastability and/or compensation for the metastability can avoid detrimental effects and/or errors to the DSM loops that may be caused by the metastability of the SAR ADCS.

A circuit includes an operational amplifier and a resistor network coupled to an output of the operational amplifier. The resistor network includes a first set of resistors coupled between the output of the operational amplifier and a first node of the resistor network, wherein the resistors of the first set are electrically connected in series with each other, a second set of resistors coupled between the first node and a second node of the resistor network, wherein the resistors of the second set are electrically connected in series with each other and include a first number of resistors, a third set of resistors coupled between the second node and a third node of the resistor network, wherein the third node is coupled to a first voltage, and wherein the resistors of the third set are electrically connected in parallel with each other and include a second number of resistors, and a resistor coupled between the first node and the second node and arranged in parallel with the second set of resistors.

A system and method is provided for measuring a voltage drop at a node. In embodiments, a circuit includes an analog-to-digital converter, a current sink, and a controller. The input of the analog-to-digital converter and the input of the current sink is coupled to the node to be measured. A set point for the current sink is determined. The output of the analog-to-digital converter during the voltage drop is sampled. And a relative voltage drop value is computed by subtracting the sampled output of the analog-to-digital converter during the voltage drop from a sampled output of the analog-to-digital converter during a steady-state condition. The current sink operating at the set point during the steady-state condition and during the voltage drop.

An analog-to-digital converter includes a primary converter and a secondary converter. The primary converter executes conversion processing to convert an analog input signal to a first digital signal through delta-sigma modulation. The secondary converter outputs a second digital signal by converting amplified analog output of a quantization error in the primary converter to the second digital signal.

A continuous time, sigma-delta analog-to-digital converter circuit includes a sigma-delta modulator circuit configured to receive an analog input signal. A single bit quantizer of the modulator generates a digital output signal at a sampling frequency. A data storage circuit stores bits of the digital output signal and digital-to-analog converter (DAC) elements are actuated in response to the stored bits to generate an analog feedback signal for comparison to the analog input signal. A filter circuit includes polyphase signal processing paths and a summation circuit configured to sum outputs from the polyphase signal processing paths to generate a converted output signal. A fan out circuit selectively applies the stored bits from the data storage circuit to inputs of the polyphase signal processing paths of the filter circuit.

A combined I/Q DAC is provided with a plurality of sources corresponding to a plurality of selectors in which the corresponding source drives the corresponding selector with a source signal to produce a corresponding pair of in-phase and quadrature-phase analog input signals to a summation network. Each selector routes its source signal responsive to a digital value of a corresponding in-phase and quadrature-phase bit pair.

An isolator of embodiments includes a ΔΣ analog-digital converter configured to convert an analog signal into a digital signal of one bit and transmit the digital signal of one bit as normal data, a time direction multiplexing circuit configured to perform time direction multiplexing of alternately performing conversion of the normal data into a digital differential signal and transmission of the digital differential signal, and transmission of a special signal different from the normal data, and an insulated transmission circuit configured to transmit the digital differential signal and the special signal transmitted from the time direction multiplexing circuit via an insulating layer.

A delta-sigma modulator includes a quantizer, a signal propagation path including a plurality of cascaded integrators coupled between the input node and the quantizer, and a feedback network including a plurality of digital-to-analog converters. In a calibration mode of operation, a first digital-to-analog converter of the plurality of digital-to-analog converters of the feedback network receives a signal including a periodic alternated digital sequence, the first digital-to-analog converter being coupled to a first integrator of the plurality of cascaded integrators, integrators of the plurality of cascaded integrators other than the first integrator operate in a gain mode of operation, the delta-sigma modulator generates a digital test signal at an output of the quantizer based on the signal including the periodic alternated digital sequence, and calibration circuitry generates a calibration signal based on the digital test signal and a reference digital word.

A quantizer for a sigma-delta modulator, a sigma-delta modulator, and a method of shaping noise are provided. The quantizer includes: an integrator configured to generate, in a K.sup.th sampling period, a quantization error signal for a K.sup.th period according to an internal signal, a quantization error signal for a (K−1).sup.th period, a filtered quantization error signal for the (K−1).sup.th period and a filtered quantization error signal for a (K−2).sup.th period; an integrating capacitor configured to store the quantization error signal for the K.sup.th period, to weight the internal signal in a (K+1).sup.th sampling period; a passive low-pass filter configured to acquire the quantization error signal for the K.sup.th period in a K.sup.th discharge period, and feed back the filtered quantization error signal to the integrator in a (K+1).sup.th sampling period and a (K+2).sup.th sampling period; and a comparator configured to quantize the quantization error signal for the K.sup.th period.