A successive approximation register analog-digital converter including a split-capacitor based digital-analog converter includes a comparator, a split-capacitor based digital-analog converter including a positive capacitor array and a negative capacitor array, and a successive approximation register logic. The positive capacitor array and the negative capacitor array each includes a positive capacitor array of a first stage and a negative capacitor array of a first stage that generate input signals of the comparator corresponding to upper bits including an MSB, respectively, a positive capacitor array of a second stage and a negative capacitor array of a second stage that generate input signals corresponding to intermediate bits, and a positive capacitor array of a third stage and a negative capacitor array of a third stage that generate input signals corresponding to lower bits of an LSB and a next to bit of the LSB.

Methods and systems for an analog-to-digital converter with near-constant common mode voltage may comprise, in an analog-to-digital converter (ADC) having sampling switches on each input line to the ADC, N double-sided and M single-sided switched capacitors on each input line: sampling an input voltage by closing the sampling switches, opening the sampling switches and comparing voltage levels between the input lines, iteratively switching the double-sided switched capacitors between a reference voltage (Vref) and ground, and iteratively switching the single-sided switched capacitors between ground and voltages that may equal Vref/2.sup.x where x ranges from 0 to m1 and m is a number of single-sided switched capacitors per input line. A common mode offset of the ADC may be less than V.sub.ADC.sub._.sub.fs/128+V.sub.ADC.sub._.sub.fs/256+V.sub.ADC.sub._.sub.fs/512+V.sub.ADC.sub._.sub.fs/1024 when m equals 4 and where V.sub.ADC.sub._.sub.fs is the full-scale voltage of the ADC.

A successive approximation register analog-digital converter including a split-capacitor based digital-analog converter includes a comparator, a split-capacitor based digital-analog converter including a positive capacitor array and a negative capacitor array, and a successive approximation register logic. The positive capacitor array and the negative capacitor array each includes a positive capacitor array of a first stage and a negative capacitor array of a first stage that generate input signals of the comparator corresponding to upper bits including an MSB, respectively, a positive capacitor array of a second stage and a negative capacitor array of a second stage that generate input signals corresponding to intermediate bits, and a positive capacitor array of a third stage and a negative capacitor array of a third stage that generate input signals corresponding to lower bits of an LSB and a next to bit of the LSB.

The disclosure provides a circuit. The circuit includes an amplifier and a digital to analog converter (DAC). The amplifier receives a reference voltage at an input node of the amplifier. The DAC is coupled to the amplifier through a refresh switch. The DAC includes one or more current elements. Each current element of the one or more current elements receives a clock. The DAC includes one or more switches corresponding to the one or more current elements. A feedback switch is coupled between the one or more switches and a feedback node of the amplifier. The DAC provides a feedback voltage at the feedback node of the amplifier.

Methods and systems for an analog-to-digital converter with near-constant common mode voltage may comprise, in an analog-to-digital converter (ADC) having sampling switches on each of two input lines to the ADC, N double-sided and M single-sided switched capacitors on each input line: sampling an input voltage by closing the sampling switches, opening the sampling switches and comparing voltage levels between the input lines, iteratively switching the double-sided switched capacitors between a reference voltage (Vref) and ground, and iteratively switching the single-sided switched capacitors between ground and voltages that may equal Vref/2.sup.x where x ranges from 0 to m1 and m is a number of single-sided switched capacitors per input line. A common mode offset of the ADC may be less than V.sub.ADC.sub._.sub.fs/128+V.sub.ADC.sub._.sub.fs/256+V.sub.ADC.sub._.sub.fs/512+V.sub.ADC.sub._.sub.fs/1024 when m equals 4 and where V.sub.ADC.sub._.sub.fs is the full-scale voltage of the ADC.

A system can include an analog input port; a digital output port; and a successive approximation register (SAR) analog-to-digital converter (ADC). The SAR ADC can include a voltage comparator V.sub.d having a first input, a second input, and an output; a first plurality of capacitors C.sub.p[0:n] that are coupled with the analog input port and each have a top plate and a bottom plate; a second plurality of capacitors C.sub.n[0:n] that are coupled with the analog input port and each have a top plate and a bottom plate; and a SAR controller coupled between the output of the voltage comparator V.sub.d and the digital output port.

The differential amplifier circuit includes: first conductivity type first to N.sup.th differential stages each causing a current corresponding to the first or second voltage received at the non-inverting input terminal to flow to a first node and a current corresponding to the output voltage signal received at the inverting input terminal to a second node; a second conductivity type differential stage receiving one of the first and second voltages at the non-inverting input terminal and receiving the output voltage signal at the inverting input terminal, and being activated when the digital data value is within a predetermined range to cause a current corresponding to the one voltage to flow to a third node and a current corresponding to the output voltage signal to a fourth node; and an output amplification stage generating the output voltage signal based on the currents respectively flowing to the first to fourth nodes.

This application describes method and apparatus for data conversion. An analogue-to-digital converter circuit receives an analogue input signal (S.sub.IN) and outputs a digital output signal (S.sub.OUT) The circuit has a sampling capacitor, a controlled oscillator and a counter for generating a count value based on a number of oscillations in an output of the controlled oscillator in a count period during a read-out phase. The digital output signal is based on the count value. The converter circuit is operable in a sampling phase and the read-out phase. In the sampling phase, the sampling capacitor is coupled to an input node for the input signal, e.g. via switch. In the read-out phase, the sampling capacitor is coupled to the controlled oscillator, e.g. via switch, such that capacitor powers the first controlled oscillator and a frequency of oscillation in the output of the first controlled oscillator depends on the voltage of the first capacitor.

Described herein are systems and methods related to a converter including a first input, a second input, and a number of digital to analog converter (DAC) cells. A DAC cell includes a first circuit, a first leg associated with a first output of the DAC cell, and a second leg associated with a second output of the DAC cell. The first circuit is configured to provide a return to zero operation. The DAC cell is configured to provide a data magnitude at a polarity on at least one of the first leg or the second leg during at least a portion of the clock cycle. The data magnitude and the polarity being provided in accordance with a first signal at the first input and a second signal at the second input.

Methods and systems for an analog-to-digital converter with near-constant common mode voltage may comprise, in an analog-to-digital converter (ADC) having sampling switches on each of two input lines to the ADC, N double-sided and M single-sided switched capacitors on each input line: sampling an input voltage by closing the sampling switches, opening the sampling switches and comparing voltage levels between the input lines, iteratively switching the double-sided switched capacitors between a reference voltage (Vref) and ground, and iteratively switching the single-sided switched capacitors between ground and voltages that may equal Vref/2.sup.x where x ranges from 0 to m1 and m is a number of single-sided switched capacitors per input line. A common mode offset of the ADC may be less than V.sub.ADC.sub._.sub.fs/128+V.sub.ADC.sub._.sub.fs/256+V.sub.ADC.sub._.sub.fs/512+V.sub.ADC.sub._.sub.fs/1024 when m equals 4 and where V.sub.ADC.sub._.sub.fs is the full-scale voltage of the ADC.