An ADC device includes a DAC circuit, a comparator circuit, a SAR decision circuit, an oscillator circuit having a delay unit, and a processing circuit. The oscillator circuit is used for generating the clock signal according to a reset signal and a delay of the delay unit. The processing circuit is used for sequentially generating multiple bit conversion signals associated with multiple different bits of the decision signal, for generating at least one guard signal which follows the multiple bit conversion signals, and then for comparing the at least one guard signal with the reset signal to adjust the delay generated by the delay unit of the oscillator circuit.

An apparatus includes a plurality of binary weighted capacitors coupled between a first input terminal of a comparator and a plurality of signal buses, wherein the plurality of binary weighted capacitors has a binary weight increasing by two times from a first capacitor to an (N−K)th capacitor, and a constant binary weight from the (N−K)th capacitor to a (N−K−2+2.sup.(K+1))th capacitor, an offset voltage generator configured to generate a digitally controlled offset voltage having 2.sup.(K+1) steps fed into a second input terminal of the comparator, and a successive approximation logic block configured to receive an output signal of the comparator, and generate an N-bit control signal for controlling the plurality of binary weighted capacitors.

A successive-approximation register analog-to-digital converter (SAR ADC), a correction method and a correction system are provided. The SAR ADC generates an original weight value sequence according to multiple original weight values. The SAR ADC converts an analog time-varying signal to establish a transforming curve corresponding to the original weight values. In addition, the SAR ADC generates an offset value sequence according to an offset of the transforming curve, uses the offset value sequence to correct the original weight value sequence to generate a corrected weight value sequence, and uses multiple corrected weight values of the corrected weight sequence to improve linearity of the transforming curve.

A successive-approximation register analog-to-digital converter (SAR ADC), a correction method and a correction system are provided. The SAR ADC generates an original weight value sequence according to multiple original weight values. The SAR ADC converts an analog time-varying signal to establish a transforming curve corresponding to the original weight values. In addition, the SAR ADC generates an offset value sequence according to an offset of the transforming curve, uses the offset value sequence to correct the original weight value sequence to generate a corrected weight value sequence, and uses multiple corrected weight values of the corrected weight sequence to improve linearity of the transforming curve.

Disclosed successive approximation register analog-to-digital converters (SAR ADCs) and conversion methods detect a statistical effect of meta-stability induced errors and limit the level of such errors. One illustrative integrated circuit chip includes: a SAR ADC that employs asynchronous bit cycles to convert a sequence of analog signal samples into a sequence of digital signal samples; and a detector that accelerates the asynchronous bit cycles when a meta-stability error bias exceeds a predetermined threshold. An illustrative analog-to-digital conversion method includes: converting a sequence of analog signal samples to a sequence of digital signal samples using a successive approximation register analog to digital converter (SAR ADC) with asynchronous bit cycles; deriving a meta-stability error bias from the sequence of digital signal samples; and accelerating the asynchronous bit cycles when the meta-stability error bias exceeds a predetermined threshold.

A charge compensation circuit for use in an analog-to-digital converter (ADC) includes at least one capacitor and at least one logic circuit. A first terminal of the capacitor is coupled to a reference voltage of the analog-to-digital converter. The logic circuit is configured to adjust a voltage at a second terminal of the capacitor according to a control signal. The control signal is determined according to at least one output bit from the analog-to-digital converter.

The amplifier load current cancellation in a current integrator comprises applying an input current to an operational transconductance amplifier provided with an integration capacitor for current integration, leading an output current of the operational transconductance amplifier through a sensing resistor, thus producing a voltage drop over the sensing resistor, generating a cancellation current dependent on the voltage drop over the sensing resistor, and injecting the cancellation current to the output current, before or after the output current passes the sensing resistor, thus eliminating a dependence of the output current on the input current.

Low power event driven pixels with passive difference detection circuit (and reset control circuits for the same) are disclosed herein. In one embodiment, an event driven pixel comprises a photosensor; a photocurrent-to-voltage converter, and a difference circuit. The difference circuit includes a source follower transistor and a switched-capacitor filter having an input coupled to the photocurrent-to-voltage converter and an output coupled to a gate of the source follower transistor. The switched-capacitor filter includes a first capacitor coupled between the input and the output of the switched-capacitor filter, a second capacitor having a first plate coupled to the output of the switched-capacitor filter, and a reset transistor coupled between a reference voltage and the output of the switched-capacitor filter. The difference circuit is configured generate a difference signal that is indicative of whether the event driven pixel has detected an event in an external scene.

Methods and systems for analog-to-digital conversion using two side branches that may be operated with overlapped timing such that a sampling phase may be overlapped with a previous conversion phase. Some embodiments provide a method of successive approximation A/D converting, comprising sampling a first signal onto a first capacitor that is configured to selectively couple to an analog input of a comparator, sampling a second signal onto capacitors that are coupled to a second analog input of the comparator and configured for charge redistribution successive approximation A/D conversion; carrying out, based on the first signal and the second signal, a charge redistribution successive approximation A/D conversion using the capacitors; and while carrying out the charge redistribution successive approximation A/D conversion based on the first and second signals, sampling a third signal onto a third capacitor that is configured to selectively couple to the analog input of a comparator.

Methods and systems for analog-to-digital conversion using two side branches that may be operated with overlapped timing such that a sampling phase may be overlapped with a previous conversion phase. Some embodiments provide a method of successive approximation A/D converting, comprising sampling a first signal onto a first capacitor that is configured to selectively couple to an analog input of a comparator, sampling a second signal onto capacitors that are coupled to a second analog input of the comparator and configured for charge redistribution successive approximation A/D conversion; carrying out, based on the first signal and the second signal, a charge redistribution successive approximation A/D conversion using the capacitors; and while carrying out the charge redistribution successive approximation A/D conversion based on the first and second signals, sampling a third signal onto a third capacitor that is configured to selectively couple to the analog input of a comparator.