A multistage noise shaping (CT-MASH) converter with phase alignment is provided. The CT-MASH converter may include a prefilter, an auxiliary path with an adjustable continuous time sigma delta converter (CTSD), and a modulator. The adjustable CTSD may provide phase alignment using one or more of a variety of techniques, such as modifying a group-delay of the CTSD by tuning a feedforward coefficient, by tuning an excess loop delay coefficient, and/or by adjusting a clock timing of the CTSD.

Methods and devices to mitigate time varying impairments in sensors are described. The application of such methods and devices to pressure sensors facing time varying parasitic capacitances due to water droplets is detailed. Benefits of auto-zeroing technique as adopted in disclosed devices is also described.

Various embodiments of the present technology may comprise methods and apparatus for an analog-to-digital converter. Methods and apparatus for an analog-to-digital converter (ADC) may be configured as a delta-sigma type ADC and include an integrator circuit formed using two switched-capacitor (SC) circuits that share a single operational amplifier. The switched-capacitor circuits receive various control signals such that one SC circuit performs sampling while the other SC circuit simultaneously performs integration.

An ANC system includes an AD converter which performs AD conversion on an external noise signal, an ANC signal generator which generates an ANC signal for canceling a noise component arriving at the ears of a user based on an output signal of the AD converter, and a level detector which detects a level of the output signal and causes the ANC signal generator to power down in response to the level. The level detector measures a time for which the level is equal to or less than a predetermined first threshold value, causes the ANC signal generator or a portion of blocks of the AD converter to power down after the measured time exceeds a predetermined value, and causes the ANC signal generator or a portion of blocks of the AD converter to return from the power down when the level exceeds a predetermined second threshold value.

A delta-sigma modulator may include a loop filter having a loop filter input configured to receive an input signal and generate an intermediate signal responsive to the input signal and a near-zero asymmetric quantizer configured to quantize the intermediate signal into a quantized output signal which is fed back as an input to the loop filter such that the quantized output signal has a plurality of quantization levels, wherein the plurality of quantization levels are asymmetric to zero.

Circuits and methods for converting digital input signals into the analog domain are described. Such circuits may perform the conversion in a segmented fashion. For example, a circuit may include a most significant bit (MSB) path and a least significant bit (LSB) path. The MSB path may include a first delta-sigma modulator having first and second outputs and a first digital-to-analog converter coupled to the first output of the first delta-sigma modulator. The LSB path comprises a second delta-sigma modulator comprising a loop filter and a quantizer. The quantizer may have an input coupled to the loop filter and to the digital filter. The LSB path may further include a second digital-to-analog converter coupled to an output of the quantizer. The circuit may further include a digital filter and/or a gain stage interposed between the MSB path and the LSB path.

Methods and devices to mitigate time varying impairments in sensors are described. The application of such methods and devices to pressure sensors facing time varying parasitic capacitances due to water droplets is detailed. Benefits of auto-zeroing technique as adopted in disclosed devices is also described.

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.

According to one embodiment, in an AD conversion circuit, a first delta-sigma conversion circuit includes a first quantizer having 1.5-bit resolution, a first signal line electrically connected to an input side of the first quantizer, and a first feedback line returning from an output side of the first quantizer to a side of an input node of the first signal line. A second delta-sigma conversion circuit includes a second quantizer having multi-bit resolution, a second signal line electrically connected to an input side of the second quantizer, and a second feedback line returning from an output side of the second quantizer to a side of an input node of the second signal line, an intermediate node of the first signal line and as intermediate node of the first feedback line being electrically connected to the input node of the second signal line.

Described herein is a modulator with improved metastability in which the control loop remains stable. In one embodiment, the modulator utilizes differently delayed feedback to successive integrators of the control loop to suppress metastability errors without compromising the stability of the control loop. This is accomplished by including one or more quantizers in the control loop. This technique may be applied to control loops of at least second order, i.e., having two or more integrator stages, where at least one feedback term after the first is non-zero.