A circuit includes a transconductance stage having first and second outputs. The circuit also includes a comparator having first and second inputs. The first input is coupled to the first output, and the second input is coupled to the second output. The comparator includes first through fifth transistors and a pair of cross-coupled transistors. The pair of cross-coupled transistors is coupled to the second current terminals of the first and second transistors. The second current terminal of the third transistor is coupled to the second current terminal of the first transistor, and the first current terminals of the first, second, and third transistors are coupled together. The second current terminals of the fourth and fifth transistors are coupled together and to the control input of the third transistor.

A continuous-time (CT) delta-sigma modulator (DSM) based analog to digital converter (ADC) in a radio receive chain supports a wide range of data rates in a power efficient way in a small die area. The ADC utilizes a 2.sup.nd order loop-filter with a single-amplifier loop-filter topology using a two stage Miller amplifier with a feed forward path and a push-pull output stage. High bandwidth operations utilize a negative-R compensation scheme at the amplifier input. Negative-R assistance is disabled for low data rate applications. With the negative-R assistance disabled, loop-filter resistor values are increased, instead of only the loop filter capacitor values to scale the noise transfer function (NTF), thereby limiting the capacitor area needed and enabling lower power operation. The NTF zero location is programmable allowing the NTF zero to be located near the intermediate frequency for different bandwidths to reduce the DSM quantization noise contribution for narrow-band (low data rate) applications.

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 provide methods and apparatus for a delta-sigma analog-to-digital converter. The delta-sigma ADC may provide a sample-and-hold circuit defined by a first switch, a second switch, a capacitor, and an amplifier, and an integrator defined by the first capacitor, a second capacitor, and the amplifier, wherein the sample-and-hold circuit and the integrator share the first capacitor and the amplifier.

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.

A quantizer and a method for a sigma-delta modulator circuit that may be used as a component within an adaptive-noise cancelling headphone are presented. An apparatus includes a quantizer to receive an input signal with successive input values and quantizes the input signal at discrete intervals. This is done by mapping the input value of the input signal at each interval to one of a plurality of quantization levels with three or more quantization levels that are non-uniformly spaced. The plurality of quantization levels has a first portion with two or more quantization levels having the same sign and being proportional to a first fraction having one as its numerator and two to a power of a first variable as its denominator, the first variable being an integer and having a different value for each of the two or more quantization levels of the first portion.

A modulator system for converting a current-varying sensor output to a digital representation is disclosed. The modulator system includes a resonator with a first resonator input and a second resonator input. The first resonator input carries a constant reference current and the second resonator input carries a varying input current. In response to a digital output, the resonator generates a complementary voltage output based on a difference between the constant reference current and the varying input current during a conversion time. The resonator resonates near or at zero frequency. An accumulated digital output is based on the accumulation of the digital output generated at each sampling clock cycle of the conversion time and represents a digital word proportional to the varying input current.

An analog-to-digital converter (ADC) includes a modulator, an integrator circuit, and first and second differentiator circuits. The modulator has a modulator input and a modulator output. The modulator input is configured to receive an analog signal, and the modulator is configured to generate digital data on the modulator output. The integrator circuit has an integrator circuit input and an integrator output. The integrator input is coupled to the modulator output. The first differentiator circuit is coupled to the integrator output, and the first differentiator circuit is configured to be clocked with a first clock. The second differentiator circuit is coupled to the integrator output, and the second differentiator circuit configured to be clocked with a second clock. The second clock is out of phase with respect to the first clock.

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.

An imaging device includes: a first temperature detection element 16 that detects temperature on the basis of infrared rays; a second temperature detection element 17 for temperature reference; and a drive circuit 10A including a switch circuit 101 including a butterfly switch circuit, a first current source 82A, a second current source 82B, a differential circuit 83, and an analog-digital conversion circuit 84. The first temperature detection element 16 and the second temperature detection element 17 are connected to a first input end 101A and a second input end 101B of the switch circuit. A first output end 101C and the first current source 82A are connected to a first input end 83A of the differential amplifier. A second output end 101D of the switch circuit and the second current source 82B are connected to a second input end 83B of the differential amplifier. An output end 83C of the differential amplifier is connected to an input portion of the analog-digital conversion circuit 84.