Stmicroelectronics (grenoble 2) Sas

Stmicroelectronics S.a.

Stmicroelectronics (crolles 2) Sas

Thomson-csf

Stmicroelectronics R&d Limited

Atmel Grenoble S.a.

Stmicroelectronics Sa (morocco)

Laurent Simony

Frederic Lalanne

Pierre Malinge

Frédéric Barbier

Graeme Storm

Lionel Vogt

Benoît Deschamps

Matthew Purcell

Marc Wingender

Alexandre Cellier

Derek Tolmie

St&eacute;phane Le Tual

Min Qu

Mhamed El Hachimi

A differential comparator circuit includes a voltage amplifier of negative gain receiving an analog input signal and generating an inverted analog input signal. The analog input signal and the inverted analog input signal form differential analog input signals. A comparator input circuit includes a first capacitive divider to generate a first signal as an average of the analog input signal and a first ramp signal, and a second capacitive divider to generate a second signal as an average of the inverted analog input signal and a second ramp signal, with the first and second ramp signals being differential ramp signals. The comparator is configured to compare the first and second signals to generate a signal transition having a timing based on the input signal.

Differential comparator circuit

In an embodiment a digital-to-analog converter includes a plurality of first capacitors, each having a first electrode and a second electrode, wherein the second electrodes are connected together and are connected to an inverting input of a first amplifier stage having its non-inverting input coupled to ground, a plurality of first switches, each of the first capacitors having its first electrode connected to a corresponding one of the first switches, wherein each of the first switches is configured to occupy a first state where the first electrode of a corresponding first capacitor is coupled to a first reference voltage and occupy a second state where the first electrode of the corresponding first capacitor is coupled to a second reference voltage different from the first reference voltage, a capacitive feedback circuit connected between the inverting input and an output of the first amplifier stage, the capacitive feedback circuit including at least one second capacitor and a controller.

Digital to analog converter

An image sensor includes an array of pixels inside and on top of a substrate. A control circuit is configured to apply voltage potentials to the substrate. During a first phase, the control circuit applies a ground potential to the substrate. During a second phase, the control circuit applies a potential positive with respect to the ground potential to the substrate.

Image sensor with a control circuit

In accordance with an embodiment, a power supply circuit includes: a first transistor device comprising a first gate associated with a first transconductance and a second gate associated with a transconductance greater than the first transconductance; and a second transistor device including a third gate associated with a second transconductance and a fourth gate associated with a transconductance greater than the second transconductance. The second transistor device is configured to supply power to at least one load, the first and the third gates are controlled by a closed regulation loop, and the second and the fourth gates are controlled by a sampled reference voltage.

Power supply circuit

An image sensor includes pixels each including: a first transistor and a first switch that are connected in series between a first node configured to receive a first potential and an internal node of the pixel, a gate of the first transistor being coupled with a floating diffusion node of the pixel; a capacitive element, a first terminal of which is connected to the floating diffusion node of the pixel; and several assemblies each including a capacitance connected in series with a second switch coupling the capacitance to the internal node. The sensor also includes a control circuit configured to control, each time a voltage is stored in one of the assemblies of a pixel, an increase of a determined value of a difference in potential between the floating diffusion node and the internal node of the pixel.

Image sensor using a global shutter and method for controlling same

A sensor includes pixels each including: a first transistor and a first switch in series between a first node and an internal node of the pixel, a gate of the first transistor being coupled to a second node; a capacitive element, a first terminal of which is connected to the second node; and a plurality of assemblies each including a capacitance in series with a second switch coupled to the internal node. The sensor includes a circuit configured to control, each time a voltage is stored in one of the assemblies, the interruption of a current between the first node and the internal node: by switching a first potential applied to a second terminal of the capacitive element; or by opening the first switch.

Image sensor and method for controlling same

A global shutter pixel includes a first transistor and a first switch series-connected between a first node of application of a potential and an internal node of the pixel. A control terminal of the first transistor is coupled to a floating diffusion node of the pixel. At least two assemblies are coupled to the internal node, where each assembly is formed of a capacitor series-connected with a second switch coupling the capacitor to the internal node. A second transistor has a control terminal connected to the internal node and a first conduction terminal coupled to an output node of the pixel. The pixel operation is controlled to store an initialization voltage from the floating diffusion on one of the capacitors and a pixel integration voltage from the floating diffusion on another of the capacitors.

Pixel and method of controlling the same

A method includes a first analog/digital conversion of an analog signal over m bits, with m less than n, associated with a first full-scale value, and a second analog/digital conversion of the analog signal over m bits associated with a second full-scale value 2times bigger than the first. The two analog/digital conversions are carried out simultaneously and respectively delivering a first intermediate digital word of m bits and a second intermediate digital word of m bits. The method also includes a digital post-processing carried out after the two analog/digital conversions and generating an n-bit digital word starting from at least one of the two intermediate digital words extended to n bits and from at least one threshold digital indication representative of at least one threshold lower than or equal to the first full-scale value.

Method and device for analog/digital conversion of an analog signal

A method of analog to digital voltage conversion including: generating a quadratic signal based on an analog time varying reference signal; generating a ramp signal based on the quadratic signal; and converting an analog input voltage to a digital output value based on a time duration determined by a comparison of the analog input voltage with the ramp signal.

Analog to digital ramp converter

An image sensor includes an active pixel, an amplifier stage, and a voltage-limiting stage. The active pixel is configured to generate an information signal. The amplifier stage is coupled to the active pixel and configured to amplify the information signal. The voltage-limiting stage is coupled to the amplifier stage and includes a current shunting device and a gain device. The current shunting device has a first terminal connected to an output of the amplifier stage, a second terminal connected to a reference voltage node, and a control terminal. The gain device is connected to the control terminal of the current shunting device and configured to decrease the voltage span required to cause the current shunting device to enter into a current shunting mode.

Image sensor with voltage-limiting device

An image sensor has a per-column ADC arrangement including first and second capacitors allowing a comparator circuit to perform correlated double sampling. The capacitors are continuously connected to, respectively, the analog pixel signal and a ramp signal without use of a hold operation. The comparator circuit comprises a differential input being connected to the junction of the two capacitors and being biased by a reference signal. The reference signal is preferably sampled and held from a reference voltage. The use of a differential input as first stage of the comparator addresses problems arising from ground voltage bounce when a large pixel array images a scene with low contrast. Connectivity of the differential input stage allows the ramp signal to see a constant capacitive load thus reduce image artifacts referred to as smear.

Analog-to-digital conversion in image sensors

A method of analog-to-digital conversion over n bits of an analog signal, including the steps of: comparing the amplitude of the analog signal with a threshold representing the amplitude of the full-scale analog signal divided by 2, where k is an integer smaller than n; performing an analog-to-digital conversion of the analog signal over n&#x2212;k bits to obtain the n&#x2212;k most significant bits of a binary word over n bits if the result of the comparison step indicates that the amplitude of the input signal is greater than the threshold, and the n&#x2212;k least significant bits of this binary word otherwise. An analog-to-digital converter and its application to image sensors.

Analog-to-digital converter

An image sensor and a method for acquiring images by sampling of the level of a voltage representative of the charge of a photodiode, in which a first sample is taken during a reset of the charge level of the photodiode; and a second sample is taken provided that the decrease slope of the voltage after the reset is lower than a threshold, said second sample replacing the first one.

Method and circuit for obtaining a sample in an image sensor

For each current image output from a pixel matrix, the digital words relative to at least one masked line of the matrix are processed to generate a current correction digital code. From this code, a black level compensation signal is generated and applied as an offset control on pixel signal amplification. If the current correct digital code does not differ from the code calculated for a previous image output by a predetermined amount, then the code for the previous image is instead used to generate the black level compensation signal.

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Grenoble, France

Laurent Simony