Abstract: An analog-to-digital converter comprising: first and second sets of ordered nodes, each first node having a corresponding second node; for each first node, a respective first resistor and current source pair, the resistor of each pair being connected to a first converter input and the current source of each pair being coupled to the respective first node; for each second node, a respective second resistor and current source pair, the resistor of each pair being connected to a second converter input and the current source of each pair being coupled to the respective second node; and a plurality of first comparators, each first comparator having its first input connected to a first node and its second input connected to the corresponding second node; wherein each of the first resistor and current source pairs are configured so as to provide an orderly progression of voltages at the first nodes and each of the second resistor and current source pairs are configured so as to provide an orderly progression of volt

Abstract: The configurations and adjusting method of a successive approximation analog-to-digital converter (SAR ADC) are provided. The provided SAR ADC includes at least one capacitor with a first and a second terminals, and a plurality of bits, each of which is connected to the at least one capacitor, wherein the first terminal receives an input signal, and the second terminal selectively receives one of a first and a second reference voltages, and a first comparator receiving an adjustable third reference voltage and a first voltage value generated by the input signal, wherein a connection of the second terminal of each the capacitor of the capacitor array is switched when the first voltage value is larger than the third reference voltage.

Abstract: The invention relates to high-resolution analog-digital converters using so-called folding differential amplifier structures composed of differential circuits (crossed differential pairs) and of loads (cascode transistors). The folding structure according to the invention comprises, in the case where it is desired to produce four curves folded at two periods in the useful range of voltages to be converted, four folding blocks (one per curve). The first comprises 7 differential circuits and eight loads, the end loads not being linked to the output of the block. The other blocks comprise 6 differential circuits and eight loads, the last load of each block not being linked to the output of this block. Gains are achieved in terms of bulk, consumption and operating speed, with respect to existing structures.

Abstract: An analog-to-digital conversion device which converts an analog input signal into a digital signal and output it includes a signal characteristic detection unit for detecting a predetermined characteristic of the input signal; a control signal generation unit for setting a resolution based on the signal characteristic detected by the signal characteristic detection unit, generating a control signal that indicates only an operation required for performing the analog-to-digital conversion at the resolution, and outputting it; and an analog-to-digital conversion unit for restricting the operation based on the control signal and converting the input signal into the digital signal at the set resolution.

Abstract: In general, a method includes comparing a first input signal with a second input signal to produce an output signal. The first input signal corresponds to an amount of light detected by a sensor, and the second input signal corresponds to an aggregated value of the output signal. The method may also include aggregating the output signal in a digital accumulator and converting a digital signal from an output of the digital accumulator to an analog signal.

Abstract: An analog-to-digital converter includes a comparison signal generation unit and a control unit. The comparison signal generation unit determines a logic level of a comparison signal by comparing an input signal with a selected reference signal based on a switch control signal in a first comparison mode, and by comparing a difference voltage with a ramp signal based on the switch control signal in a second comparison mode. The difference voltage is generated based on the input signal and the selected reference signal such that a level of the difference voltage is lower than a fine voltage level corresponding to a voltage level of the selected reference signal in the second comparison mode. The control unit generates the switch control signal based on the comparison signal and a mode selection signal.

Abstract: Systems, methods, and devices for obtaining data from a data location. The method may include generating a first value by sensing a data location under a first condition and generating a second value by sensing the data location under a second condition. The method may further include combining the first value with the second value to identify data conveyed by the data location.

Abstract: Provided is an interpolating A/D converter including a reference voltage generation circuit, an analog signal input circuit, a preamplifier group including a plurality of preamplifiers, and an interpolation circuit including a plurality of resistors. Reference voltages from the reference voltage generation circuit and an analog signal from the analog signal input circuit are input to the preamplifier group. The interpolation circuit outputs an interpolation signal by interpolating output signals of the preamplifier group. The preamplifiers amplify a differential voltage when a differential voltage between the analog signal and the reference voltages is smaller than a specified value, and the current flow of which is stopped when it is larger than the specified value. The plurality of resistors are connected in series between the adjacent amplifiers.

Abstract: A differential chopper comparator compares an input signal voltage and a first voltage, and includes a first capacitor, a second capacitor, and a differential amplification unit including a differential amplification circuit. Either the input signal voltage or the first voltage is applied to one end of the first capacitor via a first switch unit. A fixed voltage is applied to one end of the second capacitor via a second switch unit. Either a non-inverting input terminal or an inverting input terminal of the differential amplification circuit is connected to the other end of the first capacitor, and the other terminal is connected to the other end of the second capacitor. An impedance of the first switch unit side viewed from one end of the first capacitor and an impedance of the second switch unit side viewed from one end of the second capacitor are substantially same.

Abstract: A comparison circuit includes: an input circuit includes a first transistor for receiving a first signal, and a second transistor for receiving a second signal; a first current route of which the electric current is controlled by the first transistor; a second current route of which the electric current is controlled by the second transistor; a latch for amplifying potential difference between the first current route and the second current route; a comparative operation control circuit including a first switch for executing or blocking supply voltage to the drain of the first transistor, a second switch for executing or blocking supply voltage to the drain of the second transistor, and a third switch for executing supply voltage to the first current route and the second current route; a comparative operation setting circuit for controlling supply or blocking of supply of the first switch, the second switch, and the third switch.

Abstract: There is provided an AD converter including an AGC circuit that changes an input amplitude of an analog signal and outputs the analog signal to an AD converter circuit that converts the analog signal to a digital signal, and a first detection portion that compares an output range of the analog signal output by the AGC circuit with a predetermined voltage range and, based on a comparison result, controls the output range of the analog signal output by the AGC circuit.

Abstract: An analog to digital converter includes a first sample circuit that samples an analog input during a first phase of a clock. A second sample circuit samples the analog input during a second phase of the clock. A comparator compares a reference to the output of the first sample circuit during a non-overlapping time between an end of the first phase and beginning of the second phase and compares the reference to the output of the second sample circuit during a non-overlapping time between an end of the second phase and beginning of the first phase.

Abstract: An analog to digital converter includes a digital to analog converting circuit, a comparator and a signal processing circuit. The digital to analog converting circuit samples and holds an analog input signal, and converts digital output data to an analog signal to generate a hold voltage signal. The comparator compares the hold voltage signal with a reference voltage signal in response to a rising edge and a falling edge of a clock signal to generate a comparison output voltage signal. The signal processing circuit performs successive approximation based on the comparison output voltage signal to generate the digital output data.

Abstract: A folding analog-to-digital converter (ADC) is disclosed. The folding ADC includes a reference voltage generating unit generating a plurality of reference voltages, a low power analog pre-processing unit including a plurality of folders, each of which compares a voltage level of an analog input signal with a corresponding reference voltage of the plurality of reference voltages to generate a pair of differential folded outputs, a comparison unit that compares outputs of the low power analog pre-processing unit to output a digital signal, and an encoding unit that converts an output of the comparison unit into a binary code signal.

Abstract: An analog-to-digital converter with comparators with multiple, inter-coupled, outputs is provided, which may be also called a Benorion Analog-to-Digital Converter (ADC) or a Benorion Converter. The analog-to-digital converter includes a plurality of comparators operably coupled for receiving an analog input signal and configured for comparing the analog input signal with a plurality of voltage reference signals. Each comparator of the plurality is configured for generating a plurality of comparator outputs comprising a primary comparator output, and at least one additional comparator output selected from the group consisting of positive comparator outputs and negative comparator.

Abstract: A successive approximation type A/D converter includes: a reference signal generating section generating a reference signal; a comparator comparing an analog signal input thereto with the reference signal and converting the analog signal into a digital signal; and a control section controlling the reference signal to perform oversampling by executing an A/D conversion process on the analog signal at the comparator plural times such that the analog signal is A/D-converted into a digital value of N bits at the first A/D conversion process and such that the second and subsequent A/D conversion processes are performed starting with a lower bit of the (N?n)-th or lower order with upper n bits of the N-bit digital value obtained at the first A/D conversion process fixed.

Abstract: An analog-to-digital converter converts an analog signal into a digital signal by measuring a time period until a magnitude relation between a voltage level of a reference signal that changes along with time and a voltage level of the analog signal is inverted. The converter comprises a holding unit which holds, as a voltage level that is an analog value, an offset value of the analog-to-digital converter upon analog-to-digital converting a reference voltage level by the analog-to-digital converter, wherein the offset value of the analog-to-digital converter is corrected by changing the voltage level of the analog signal by the voltage level of the offset value held by the holding unit.

Abstract: An analog-to-digital conversion circuit includes: comparators to compare an input analog signal and one of reference voltages corresponding to each operation in an analog-to-digital conversion; an interpolating comparator to compare the input analog signal and a determination voltage between first and second reference voltages corresponding to two comparators; a correction value acquisition circuit to calculate a correction value to correct an error between the input analog signal and the determination voltage; a correction value application circuit to set the correction value in the interpolating comparator; a test voltage generation circuit to supply the two comparators with a first test voltage corresponding to one of the determination voltages; a common voltage generation circuit to supply the two comparators with a second test voltage; and a correction value calculation circuit to calculate respective correction values corresponding to the determination voltages based on errors corresponding to the first

Abstract: The invention relates to an N-bit asynchronous Quantizer including a 2N?1 signal amplifier stages (G12-G2N?12) arranged in series, the input of the first stage being capable of receiving a signal to be quantized; 2N?1 comparators (C12-C2N?12), one comparator being connected to the output of each amplifier stage (G12-G2N?12), and capable of comparing the value of this output with a predetermined threshold value; and at least 2N?2 delay lines (D12-D2N?12) placed at the output of the 2N?2 first comparators, the signals supplied at the output of the delay lines (D12-D2N?12) and of the last comparator constituting at any instant the quantized binary values of the input signal with a time shift.

Abstract: First and second track and hold stages track and store an input voltage for a sample of an analog input signal. A coarse reference ladder provides a plurality of coarse references. In one embodiment, the coarse reference ladder includes a first coarse reference and a second coarse reference ladder. A coarse ADC performs a first comparison of the input voltage and the plurality of coarse references and outputs a coarse output based on the first comparison. A switch matrix includes a plurality of switches and is configured to close a switch corresponding to a coarse reference based on the coarse output. A fine reference ladder provides a plurality of fine references. A fine ADC performs a second comparison of the input voltage and the plurality of fine references and outputs a fine output based on the second comparison. Logic outputs a digital output for the sample of the analog input signal based on the coarse output and the fine output.

Abstract: In a differential amplifier, input terminals to which a differential input is given are connected to gates of input transistors, respectively. One ends of capacitive devices are connected to sources of the input transistors, respectively. A switching section switches connection between the other ends of the capacitive devices and the input terminals according to a control clock at each phase.

Abstract: The present invention is related to an analog to digital converter circuit. The circuit comprises at least one input node for applying an analog input voltage signal (Vin), means for sampling said analog input voltage signal, a first array of capacitors arranged for receiving the sampled analog input voltage signal, a digital delay line connected to the first array of capacitors and arranged for being enabled by a clock generator and for generating a staircase or slope function by means of the first capacitor array, taking into account the sampled analog input voltage signal, a comparator arranged for comparing a converted signal with a reference voltage (Vref), said converted signal being a version of said sampled analog input voltage converted according to said staircase or slope function, and for generating a stop signal based on the comparison result thereby latching the digital delay line and thereby acquiring the digital code.

Abstract: A method and apparatus for performing pipelined capacitive folding and interpolation analog-to-digital conversion. In one embodiment, the apparatus comprises a multistage pipelined analog-to-digital converter having: a distributed sample/hold and preamp, folding and interpolation unit which combines a plurality of preamplified signals using a capacitive folding and capacitive interpolation; and a decoding unit coupled to decode the output signals from the folding and interpolation unit. The distributed sample/hold and preamp drastically improves the input dynamic range and hence increases ADC over all linearity. This technique offers an inherent dynamic offset cancellation in every sample and can be implemented in submicron CMOS, using the core digital supply.

Abstract: A coarse reference ladder provides a plurality of coarse references. A coarse ADC receives an input voltage. The coarse ADC performs a first comparison of the input voltage and the plurality of coarse references and outputs a coarse output. A switch matrix is configured to close a switch based on the coarse output. An input line corresponding to a coarse reference is coupled to the switch matrix. The input line is precharged to the input voltage. The input line settles from the precharged input voltage to the coarse reference. A fine reference ladder provides a plurality of fine references based on the coarse reference. A fine ADC receives the input voltage and performs a second comparison of the input voltage and the plurality of fine references and outputs a fine output. Logic outputs a digital output for the input voltage based on the coarse output and the fine output.

Abstract: An amplifier that is operated between first and second power supplies includes a transistor pair having control terminals to which input signals are input, a load resistor pair that is provided between each transistor of the transistor pair and the first power supply, a constant current source that is provided between the second power supply and the transistor pair, and a first switch that is connected with the constant current source in series between the second power supply and the transistor pair, the first switch being turned on or off in accordance with a clock signal.

Abstract: A radio communication device performs baseband processing by subjecting a received signal to an AD conversion at a predetermined sampling frequency and converting a digital signal resulting from the AD conversion into a baseband signal by frequency conversion. The device includes a frequency converting unit configured to convert the resulting digital signal into a complex baseband signal. The device further includes a waveform shaping unit configured to subject the baseband signal to waveform shaping, and a down-sampling unit configured to subject the baseband signal to sample discrete reduction.

Abstract: A mobile device having first and second modes of operation is operated responsive to detection of a predefined localized movement of a housing of the mobile device using a sensor associated therewith. The detected predefined localized movement is associated with first and second functions of the mobile device responsive to a user input assigning the detected predefined localized movement thereto. A first device function is performed responsive to detection of the predefined localized movement in the first mode of operation, and a second device function is performed responsive to detection of the predefined localized movement in the second mode of operation. A predetermined delay time may also be associated with the predefined localized movement, and the first and/or second functions may be performed at the predetermined delay time after detecting the predefined localized movement.

Abstract: An amplifying circuit includes a pair of MOS transistors; an amplifier that amplify a difference between potentials of differential output nodes coupled to drains of the pair of MOS transistors; cancel circuits that cause cancel current to flow to one of the differential output nodes when the amplifier amplifies a voltage between the differential output nodes and that shut off, after the amplifier performs the amplification operation, inflow of the cancel current; and a controller that performs setting so that a potential of first one of the differential input signals is equal to a potential of another one of the differential input signals, that compares, before the inflow of the cancel current, potentials generated at differential output nodes when the difference between potentials of the differential output nodes is amplified, and that sets the cancel current so that the potentials are reversed after the inflow of the cancel current.

Abstract: A method and system for sampling values. Multiple values are sampled concurrently. One of the values is stored while another one of the values is converted to a corresponding digital value by an analog-to-digital converter (ADC). Subsequently, the stored value is made available to the ADC.

Abstract: A method and apparatus is disclosed to extend a dynamic input range of an analog to digital converter (ADC). A composite ADC may include one or more ADCs. The one or more ADCs compare a signal metric of an analog input signal to quantization levels to produce intermediate digital output signals using one or more non-clipping input values. The composite ADC may select among the one or more intermediate digital output signals based on the signal metric of the analog input signal to produce a final digital output.

Abstract: A logarithmic analog to digital conversion method for an analog input signal includes a logarithmic amplification with progressive compression of the input signal delivering a sequence of several secondary analog signals. The trend of the values of at least some of the secondary signals is a function of the values of the analog input signal including regions corresponding to a linear trend of the secondary signals as a function of that of the input signal expressed in a logarithmic scale. The method also includes a comparison of at least some of the secondary signals of the sequence with a common reference signal whose value lies within each of regions, supplying a thermometric code information item, and a generation of a first digital word from the thermometric code information item.

Abstract: A successive approximation type A/D converter circuit includes a comparator circuit which determines which of an input analog voltage and a comparison voltage is larger, a register which successively takes in and stores a comparison result, and a local DA converter circuit which converts a register value into a voltage to generate the comparison voltage. The comparator circuit includes amplifier stages and a feedback capacitor connected to an input terminal of one of the amplifier stages, takes in an analog voltage during a first period, receives a input voltage depending on a potential difference between the analog and comparison voltages and amplifies the input voltage in the amplifier stage during a second period, and applies positive feedback to an input terminal of a corresponding amplifier stage via the feedback capacitor so as to impart a hysteresis of 1 LSB or less when an output of the comparator circuit changes.

Abstract: In a wireless chip receiving the multi-rate data according to the related art, power consumption and a circuit area of an analog-to-digital converter become large. In a digital calibration type analog-to-digital converter including both a reference analog-to-digital conversion unit and a main analog-to-digital conversion unit, when processing the high-sample rate wireless receive signal, both the reference analog-to-digital conversion unit and the main analog-to-digital conversion unit are operated to configure a general digital calibration type analog-to-digital converter, and when processing a low-sample rate wireless receive signal, analog-to-digital conversion is performed by using the reference analog-to-digital conversion unit and operations of the main analog-to-digital conversion unit or the like are stopped to remarkably reduce power consumption.

Abstract: A folding circuit and an analog-to-digital converter wherein a response to small signals is improved, a load on a clock signal can be reduced, and the increase of circuit area can be prevented. The circuit includes a reference voltage generating circuit that generates a plurality of differential voltages as reference voltages, and a plurality of amplification circuits that convert differential voltages between the plurality of reference voltages and an analog input voltage to differential currents, and output these differential currents. The output ends of the amplification circuits are alternately connected. Each of the amplification circuit is configured by a differential amplifier circuit having cascode output transistors (145, 146). A switch (144), which is turned on in synchronization with the control clock, is provided between the both sources of the cascode output transistors (145,146).

Abstract: Systems, methods and computer program products for correcting polarity decision associated with a polarity comparator in an analog-to-digital converter are described. The polarity comparator may perform polarity decision to determine whether an analog signal is greater or smaller than zero. If the voltage difference is greater than zero, then the analog signal may be output to other comparators without polarity inversion. If the voltage difference is smaller than zero, then the signal polarity of the analog signal may be inverted before being output to other comparators. One or more redundant comparators also may be used to correct offsets of the polarity comparator to reduced errors associated with the polarity decision.

Abstract: An external input operation clock signal is required for operating a conventional A/D converter, and the performance of the A/D converter is undesirably determined by the characteristics of the external input operation clock. A clock generator circuit for automatically generating an operation clock is provided inside an A/D converter to make the A/D converter require no external input operation clock. Further, a circuit for detecting the operation times of the constituents of the A/D converter is provided to generate a clock with which the A/D converter is optimally operated, thereby realizing high-speed operation and low power consumption.

Abstract: Increase of power consumption is reduced, and the operational speed is improved. A comparator includes a comparing section which outputs a result of comparison between a first voltage and a second voltage which constitute an input differential signal, a first positive feedback section which operates in synchronism with a first clock signal, amplifies the result from the comparing section, and outputs the amplified result to an output node pair, and a second positive feedback section which operates in synchronism with a second clock signal, and provides positive feedback to the output node pair.

Abstract: There is provided an analog-to-digital converter that comprises an analog signal input for receiving an analog signal; a reference voltage input for receiving a reference voltage signal; and a plurality of comparators, one input of each comparator being connected to the analog signal input, and the other input of each comparator being connected so as to receive a respective portion of the reference voltage signal; wherein at least one of the plurality of comparators can be selectively activated and deactivated in order to determine a mode of operation of the analog-to-digital converter.

Abstract: In a latch circuit having a bistable pair of cross connected transistors of a first polarity and a third transistor of a second polarity, a current signal greater than a bias current is received at a latch circuit port, amplified with the third transistor, and applied to the latch circuit port. This decreases the time in which the latch circuit port receiving the current signal greater than the bias current reaches a steady state voltage.

Abstract: Various embodiments of the present invention provide systems and methods for analog to digital conversion. For example, a retimed analog to digital converter is disclosed that includes a first set of sub-level interleaves and a second set of sub-level interleaves. The first set of sub-level interleaves includes a first sub-level interleave with a first set of comparators synchronized to a first clock phase, and a second sub-level interleave with a second set of comparators synchronized to a second clock phase. The second set of sub-level interleaves includes a third sub-level interleave with a third set of comparators synchronized to a third clock phase, and a fourth sub-level interleave with a fourth set of comparators synchronized to a fourth clock phase.

Abstract: An apparatus, protocol and methods for reducing vehicle energy consumption and for precise electronic event control, by implementing full CPU off-loading, using pulse-width modulation (PWM) with analog feedback diagnosis enabling real-time operation. Accordingly, analog feedback is used for external integrated circuits (IC) controlled by a PWM output, for processes to be analyzed. The apparatus includes a microprocessor that integrates an autonomous PWM module and an analog-to-digital converter (ADC) group manager, each including register modules for enabling analog-to-digital signal conversion comparisons of PWM feedback data, and generating of an interrupt commands when required.

Abstract: An integrated circuit comprises a threshold generation circuitry for generating at least one differential voltage signal. The threshold generation circuitry comprises at least one common mode current generation circuit arranged to generate at least one common mode current signal, whereby said at least one common mode current signal is combined with at least one input current signal to produce a combined current signal comprising a combined signal common mode component. Conversion circuitry is arranged to receive the combined current signal and convert the combined current signal into the at least one differential voltage signal for use within the comparator circuit. The threshold generation circuitry further comprises feedback circuitry arranged to receive an indication of the combined signal common mode component, compare the received indication to a reference value, and regulate the at least one common mode current signal based at least partly on the comparison results.

Abstract: An A/D converter provides one or more operational amplifiers as components. The A/D converter includes a current controlling unit that is activated before an actual operation of the A/D converter to control a current of at least one of the operational amplifiers based on a settling characteristic of the operational amplifier.

Abstract: A high-precision A/D conversion is realized while the number of external terminals used for an A/D converter is reduced. At the time of sampling, first to fifth switches are turned on and a sixth switch is turned off. Since a first resistor is set to a resistance value optimum for sampling, an impedance in the direction from a node A to the left side and an impedance in the direction from a node B to the left side almost match, and a large noise-cancelling effect is obtained. At the time of successive approximation, the first, second, third, and fifth switches are turned off and the fourth and sixth switches are turned on. Since a second resistor is set to a resistance value optimum for the successive approximation, the impedance in the direction from the node A to the left side and the impedance in the direction from the node B to the left side almost match, and a large noise-cancelling effect is obtained also at the time of successive approximation.

Abstract: A solid-state image pickup device includes a pixel array including pixels arranged in a matrix, a pixel signal readout unit, and a timing control unit for controlling processing of the pixel signal readout unit by using a timing signal. The pixel signal readout unit includes: a plurality of comparators for comparing a readout signal potential with a reference voltage to generate a determination signal and outputting the determination signal, and a plurality of counters. Each counter counts a comparison time of each corresponding one of the comparators. The timing control unit (a) divides a predetermined processing period into at least a first-time readout period, a first comparison period, a second-time readout period, and a second-time comparison period, (b) classifies the periods into two periods, and (c) generates a timing signal of processing of each divided period by counting for each divided period in the counter.

Abstract: A method and apparatus for performing pipelined capacitive folding and interpolation analog-to-digital conversion. In one embodiment, the apparatus comprises a multistage pipelined analog-to-digital converter having: a distributed sample/hold and preamp, folding and interpolation unit which combines a plurality of preamplified signals using a capacitive folding and capacitive interpolation; and a decoding unit coupled to decode the output signals from the folding and interpolation unit. The distributed sample/hold and preamp drastically improves the input dynamic range and hence increases ADC over all linearity. This technique offers an inherent dynamic offset cancellation in every sample and can be implemented in submicron CMOS, using the core digital supply.

Abstract: A differential amplifier circuit is provided with an operational amplifier and a modulator. The operational amplifier includes a feedback capacitance, and amplifies an analog input signal and outputs an amplified analog output signal. The modulator is connected to a virtual ground point of an input terminal of the operational amplifier, and the modulator switches between a pair of inputted analog differential signals to alternately select one of the analog differential signals based on a predetermined modulation control signal, and outputs a selected analog differential signal. The differential amplifier circuit alternately folds and amplifies the analog input signal within a predetermined input level limit range to generate a signal having different polarities sequentially so as to start from a voltage potential of the virtual ground point at a timing of the modulation control signal. In addition, an converter apparatus is provided with the differential amplifier circuit.

Abstract: A circuit includes an analog-to-digital converter configured to receive an analog input signal and generate first digital values at a first sampling rate. The first digital values have a first bit-width. The circuit also includes an interpolator configured to receive the first digital values and generate second digital values at a second sampling rate higher than the first sampling rate. The second digital values have a second bit-width equal to or greater than the first bit-width. The circuit further includes a digital filter configured to receive the second digital values and perform bit-width reduction in a recoverable manner to generate third digital values. The third digital values have a third bit-width less than the first and second bit-widths. The circuit could optionally include a recovery circuit configured to process the third digital values to generate recovered digital values at the first sampling rate. The recovered digital values have the first bit-width.

Abstract: A telescopic differential operational amplifier circuit for use in a pipelined A/D converter is provided with two auxiliary differential amplifiers connected to two cascode circuits, each including cascode-connected first to fourth transistors. During the sampling phase, first and second switches are turned on to apply a predetermined bias voltage to the gates of first and fourth transistors, and the input terminal of the differential operational amplifier circuit is set to a common mode voltage. During the hold phase, the first and second switches are turned off so that a voltage of each of the gates of the first and fourth transistors change to follow an input signal inputted via the input terminal with coupling capacitors operating as a level shifter of the input signal. Then the differential operational amplifier circuit performs push-pull operation operative only in a transconductance drive region, and is prevented from operating in a slewing region.

Abstract: A method and apparatus for performing pipelined capacitive folding and interpolation analog-to-digital conversion. In one embodiment, the apparatus comprises a multistage pipelined analog-to-digital converter having: a distributed sample/hold and preamp, folding and interpolation unit which combines a plurality of preamplified signals using a capacitive folding and capacitive interpolation; and a decoding unit coupled to decode the output signals from the folding and interpolation unit. The distributed sample/hold and preamp drastically improves the input dynamic range and hence increases ADC over all linearity. This technique offers an inherent dynamic offset cancellation in every sample and can be implemented in submicron CMOS, using the core digital supply.