There is provided a solid-state image pickup device including ADCs that can be arranged in a limited space. The potential of a pixel signal outputted through a vertical readout line is held at a node. A plurality of capacitors are capacitively coupled to the node at which the pixel signal is held. The potential of the node is decreased in a stepwise manner by sequentially switching the voltages of the counter electrodes of the capacitors by the control of transistors. A comparator compares the potential of the node with the potential of the dark state of the pixel, and determines the upper bits of a digital value when the potential of the node becomes lower than the potential of the dark state. Following this, the conversion of the lower bits of the digital value is started. Therefore, it is possible to simplify the configuration of each ADC and arrange each ADC in a limited space.

A sampling circuit includes: a first capacitor including a first terminal and a second terminal; a second capacitor including a third terminal and a fourth terminal; a first input node configured to receive a first input voltage that is one of a differential input voltage; a second input node configured to receive a second input voltage that is the other of the differential input voltage; a first switch circuit configured to be provided between the first input node and the first terminal; a second switch circuit configured to be provided between the second input node and the third terminal; a third switch circuit configured to be provided between the first terminal and the third terminal; and a fourth switch circuit configured to be provided between the second terminal and the fourth terminal.

The present disclosure relates to the field of microelectronics and solid-state electronics, and in particular to a calibration system and method for weighting errors brought about by parasitic capacitance in split capacitor-based successive approximation analog-to-digital converters. The method uses an MSB array that does not add additional capacitors, only a switch S.sub.M to reduce the comparator design difficulty. Meanwhile, an LSB array may add a calibration DAC array C.sub.A including a binary array of P-bit unit capacitors, a calibration structure C.sub.fraq, and a ground switch S.sub.k. The calibration structure C.sub.fraq includes four unit capacitors and two switches S.sub.1 and S.sub.2. By controlling the switches S.sub.1 and S.sub.2 different capacitance values can be generated to reduce the chip area consumption. This structure can reduce the error to LSB/4 and the weighting error of the ADC, and increases the effective number of bits of the ADC without excessively increasing comparator gain.

An example apparatus includes bias control circuitry and sampling circuitry. The example sampling circuitry includes a first switch coupled to a first capacitor in series between an input voltage terminal and a common mode voltage terminal, the first switch including a first terminal coupled to the input voltage terminal. Additionally, the example sampling circuitry includes a second switch coupled to a second capacitor in series between the input voltage terminal and the common mode voltage terminal, the second switch including a first terminal coupled to the input voltage terminal. The example sampling circuitry also includes a third switch including a first terminal, a second terminal, and a control terminal, the first terminal of the third switch coupled to a power supply terminal, the second terminal of the third switch coupled between the first switch and the first capacitor, the control terminal coupled to the bias control circuitry.

A method for converting an unknown analog voltage to a digital output signal includes receiving the unknown voltage, establishing a first stability threshold to distinguish between stable and metastable measurements of a voltage difference between the unknown voltage and a reference voltage, measuring that difference, determining whether the difference is greater or less than the first stability threshold, in response to determining that the difference is greater than the first stability threshold, yielding an output indicative of which one of the unknown and reference voltages is greater, in response to determining that the difference is less than the first stability threshold, overruling the output and assigning a predetermined output value indicative of which one of the unknown and reference voltages is greater, and deriving, from the output value indicative of which one of the unknown and reference voltages is greater, at least one bit of the digital output signal.

A method for converting an unknown analog voltage to a digital output signal includes receiving the unknown voltage, establishing a first stability threshold to distinguish between stable and metastable measurements of a voltage difference between the unknown voltage and a reference voltage, measuring that difference, determining whether the difference is greater or less than the first stability threshold, in response to determining that the difference is greater than the first stability threshold, yielding an output indicative of which one of the unknown and reference voltages is greater, in response to determining that the difference is less than the first stability threshold, overruling the output and assigning a predetermined output value indicative of which one of the unknown and reference voltages is greater, and deriving, from the output value indicative of which one of the unknown and reference voltages is greater, at least one bit of the digital output signal.

There is provided an integrator including: a first order delay unit which outputs an output signal obtained by delaying a signal in accordance with an input signal; a first feedback unit which generates a first feedback signal in accordance with the output signal; a second feedback unit which generates a second feedback signal in accordance with the output signal; an addition and subtraction unit which adds and subtracts the first feedback signal and the second feedback signal, respectively, to and from the input signal, for an input to the delay unit; and a control unit which causes the second feedback unit to operate as a delay circuit during the first period, and causes the second feedback unit to operate as a gain circuit having a gain smaller than 0 during the second period.

An analog to digital converter (ADC) circuit including: a voltage-controlled delay circuit (VCDC) configured to: sample a received analog signal based on an input clock signal to generate analog signal samples; generate an output signal representative of the input clock signal shifted in the time domain with a delay based on the analog signal samples; and a time to digital converter (TDC) coupled to the voltage-controlled delay circuit and configured to generate a digital output signal based on the output signal.

The systems and methods discussed herein related to analog to digital conversion. An apparatus can include an analog to digital converter including a loop circuit and a comparator circuit. The apparatus can also include a first circuit configured to provide comparator offset calibration for the comparator circuit and a second circuit configured to provide loop calibration for the loop circuit.

The systems and methods discussed herein related to analog to digital conversion. An apparatus can include an analog to digital converter including a loop circuit and a comparator circuit. The apparatus can also include a first circuit configured to provide comparator offset calibration for the comparator circuit and a second circuit configured to provide loop calibration for the loop circuit.