According to one embodiment, in a semiconductor integrated circuit, a second switch has a first end connected to a first end of a capacitive element and a second end connected to a node of a reference potential. A third switch has a first end connected to the first end of the capacitive element and a second end connected to an input node of an amplifier circuit. A control circuit maintains the second switch in an on state while maintaining a first and the third switches in an off state in a first period and maintains the first switch in an on state while maintaining the second and third switches in an off state in a second period after the first period. End timings of the second period in the plurality of DA converters are synchronized with each other in response to a signal from a global circuit.

An imaging system may include an image sensor. The image sensor may have an array of image pixels arranged in rows and columns. Each column of image pixels may be coupled to column readout circuitry via a corresponding column line. The column readout circuitry may include analog-to-digital conversion circuitry. The analog-to-digital conversion circuitry may include split MSB and LSB capacitor banks. The MSB capacitor bank may include capacitors selectively coupled to a coarse reference voltage or a fine reference voltage. The LSB capacitor bank may include capacitors electively coupled to the coarse reference voltage.

A method and circuit for performing vector-matrix multiplication may include converting an input vector of binary-encoded values into analog signals using one-bit DACs, and sequentially performing a vector-matrix multiplication operation for each bit-order. The method may also include, for each sequentially performed operation, operating a switch that corresponds to a current bit-order. Operating the switch may cause a value corresponding to an output of the multiplier to be stored on a capacitor corresponding to the current bit-order. A time interval during which the switch is operated may be non-uniform with respect to time intervals for other switches, and the time interval may be based at least in part on a settling time of the capacitor. The method may also include performing a bit-order weighted summation of values stored on the plurality of capacitors to generate a result of the vector-matrix multiplication.

A successive approximation (SA) AD converter includes a SA control circuit generating a digital output signal based on an output from a comparator; a first capacitor coupled to an input of the comparator, receiving an analog input signal, and capable of storing electric charges; a second and a third capacitor groups coupling to a reference voltage and storing electric charges previously. The SA control circuit operates for each SA step that the second or the third capacitor group is coupled to a non-inverting input of the comparator and the other is coupled to an inverting input of the comparator based on the output from the comparator. The SA control circuit operates that capacitor terminals of the second and the third capacitor groups coupled to the input of the comparator have the same potential when the reference voltage is stored previously in the second and the third capacitor groups.

A successive approximation ADC includes: a comparator generating a judge signal related to an input analog and a reference signals; a SAR successively generating a register signal including a first and a second bit signals based on the judge signal and generating an AD conversion value of the input analog signal; a thermometer decoder switching different thermometer code conversion rules and converting the first bit signal to thermometer codes corresponding to the different thermometer code conversion rules in one AD conversion cycle; a first and a second DA converters respectively converting the thermometer codes to a first analog signal and the second bit signal to a second analog signal; an average value calculator averaging the AD conversion values by the thermometer codes. Two of the different thermometer codes have values that a high-order bit and a low-order bit groups by dividing total bits of the thermometer code equally are exchanged.

An ADC circuit is provided. The ADC circuit may include an array of bit capacitors; a comparator electrically connected to the bit capacitors; a NOR gate electrically connected to the comparator; an AND gate to create an asynchronous clock (ACLK) based on a digital output from the NOR and a synchronous clock (CLKin); a delay control circuit to receive the asynchronous clock and to create a delayed asynchronous clock (ACLKd); and a SAR control circuit to receive a digital output from an output end of the comparator, to receive the delayed asynchronous clock, to transmit a bit control signal (B<9:1>) to the bit capacitors, and to transmit a delay control word (DL<7:1>) to the delay control circuit. The ADC circuit can create an asynchronous comparator clock (CKcmp) with a maximum delay value (Td_max), thus leading to an improved conversion linearity and a reduced power consumption.

An analog-to-digital converter includes a first converter stage, a second converter stage coupled to the first converter stage to quantize a residue signal of the first converter stage, and an inter-stage converter disposed between the first and second converter stages. The inter-stage converter is configured to convert between a first domain and a second domain. The inter-stage converter is configured to process the residue signal of the first converter stage such that a range of the residue signal matches a full scale of the second converter stage.

An image sensor may include an analog-to-digital converter. The converter may have a input capacitor, one or more metal-oxide-semiconductor capacitors, a digital-to-analog converter, and a comparator. An input signal may be sampled onto the input capacitor while the metal-oxide-semiconductor capacitors are activated. A few conversion steps may be performed while the metal-oxide-semiconductor capacitors are activated. After the few conversion steps, the metal-oxide-semiconductor capacitors are deactivated to realize a voltage gain, which makes the converter less sensitive to comparator noise.

A digital-to-analog converter (DAC) includes a plurality of reference modules, an output capacitor configured to output the analog voltage, and a sharing switch coupled between the output capacitor and the reference modules. The reference modules are mutually connected in parallel. Each reference module includes a reference capacitor and a reference switch connected in series. A plurality of reference capacitances of the reference capacitors are substantially identical. The reference switches are controlled by a plurality of control signals. The control signals are corresponding to a control code. The DAC produces an analog voltage according to the control code. An analog difference, between a first analog voltage corresponding to a first control code and a second analog voltage corresponding to a second control code, monotonically increases or monotonically decreases as a first value corresponding to the first control code increases. The first control code is consecutive to the second control code.

A capacitive analog-to-digital converter, an analog-to-digital conversion system, a chip, and a device. The capacitive analog-to-digital converter includes: a first capacitor array, including N first capacitor banks that include M first capacitors, where M is a positive integer greater than N; M first switches, respectively connected to first electrode plates of the M first capacitors in a one-to-one correspondence to enable a successive approximation logic controller to control connections of the first electrode plates of the M first capacitors with an output of a voltage generation circuit and with a first sampling voltage output by controlling the M first switches; a comparator, including a first input, a second input and an output; and the successive approximation logic controller, connected to the output of the comparator, and configured to control the M first switches according to comparison results output by the output of the comparator.