Stmicroelectronics (research & Development) Limited

Stmicroelectronics (grenoble 2) Sas

Stmicroelectronics Gmbh

Stmicroelectronics R&d Limited

Stmicroelectronics Sa (morocco)

Graeme Storm

Matthew Purcell

John Kevin Moore

Denise Lee

Christophe Mandier

Neale Dutton

Laurence Stark

Derek Tolmie

Min Qu

Pascal Mellot

Bruce Rae

Laurent Simony

Tarek Lule

Jonathan Ephriam David Hurwitz

Alexios Alexandropoulos

Mhamed El Hachimi

Aravind Venugopalan Nair Jalajakumari

Rachel Elliott

Michael Wigley

A driver circuit for a laser diode is configured to pass a current. The circuit includes a charge-pump configured to generate an output boosted positive supply rail voltage. At least one switch is configured to couple the output of the charge-pump to a terminal of the laser diode and to isolate the positive supply rail from the terminal of the laser diode when the charge-pump is enabled.

Laser diode current driving apparatus

An apparatus includes a single photon avalanche diode pixel that includes a single photon avalanche diode and an output transistor configured to provide an analog output current from the single photon avalanche diode. The single photon avalanche diode pixel is configured to operate in a first mode to output a digital single photon detection event. The single photon avalanche diode pixel is further configured to operate in a second mode to output the analog output current indicating a level of illumination of the pixel.

Apparatus for detecting illumination levels

A ranging apparatus includes an array of light sensitive detectors configured to receive light from a light source which has been reflected by an object. The array includes a number of different zones. Readout circuitry including at least one read out channel is configured to read data output from each of the zones. A processor operates to process the data output to determine position information associated with the object.

Ranging apparatus

An embodiment device includes an optical source configured to generate an optical carrier including an optical pulse train; and a modulator configured to modulate an amplitude of the optical pulse train, based on data generated by a data source, to produce a modulated optical signal.

Devices and methods for transmitting and receiving in an optical communications system

A pixel arrangement includes a photodiode, a reset transistor configured to be controlled by a reset signal and coupled to a reset input voltage, a transfer gate transistor configured to transfer charge from the photodiode to a node, wherein the transfer gate transistor is controlled by a transfer gate voltage, and a source follower transistor controlled by the voltage on the node and coupled to a source follower voltage. A capacitor is coupled between the node and an input voltage. During a read operation the input voltage is increased to boost the voltage at the node. The increased input voltage may, for example, be one the reset input voltage, said source follower voltage, said transfer gate voltage and a boosting voltage.

Pixel circuit

An image sensor having improved dynamic range includes a signal that is read out for a selection of pixels which act as a calibration to govern the choice of exposure levels to be applied to the rest of the array. In this way, the sensor is operable to adapt to variations in scene intensity. The pixels in the array are vertically and horizontally addressed so as to enable accounted for small areas of intensity variation across an imaged scene.

Image sensor with improved dynamic range

An image sensor includes an array of pixels. Each pixel has at least one photo-sensitive element. Readout circuitry receives an analog signal from each pixel at a first time and at a second time, between which the analog signal changes. The image sensor further includes associated support circuitry which is a source of time variant noise. The signal level at both first and second times includes pixel noise. Sample and hold circuitry is provided to maintain substantially level at least a proportion of this support circuitry noise time invariant at the sensor output between the first time and the second time.

Image sensor with sample and hold circuitry for addressing time variant noise

Each column of pixels in an image sensor array has at least two column bitlines connected to an output of each pixel. A readout input circuit includes first inputs and a second input. Each first input is connected, via a capacitance, to a comparator input node. The second input is connected via a capacitance to the same comparator input node. The first inputs receive, in parallel, an analog signal acquired from the pixels via the column bitlines. The analog signals vary during a pixel readout period and have a first level during a first calibration period and a second level during a second read period with the analog signals being constantly read onto the capacitances during both the first calibration period and the second read period. The comparator compares an average of the signals on the plurality of first inputs to the reference signal.

Image sensor arrangement

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

An image sensor has a per-column ADC arrangement including first and second capacitors for correlated double sampling, and a comparator circuit. 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 amplifier having one input connected to the junction of the two capacitors and another input connected to a reference signal. The reference signal is preferably sampled and held from a reference voltage. The use of a differential amplifier as first stage of the comparator addresses problems arising from ground voltage bounce when a large pixel array images a scene with low contrast.

Analog-to-digital conversion in image sensors using a differential comparison

An image sensor includes a pixel array, and a correlated double sample circuit coupled to one of the pixels in the pixel array. The correlated double sample circuit includes first and second inputs, and first and second sample capacitors respectively coupled to the first and second inputs. The first input is for receiving an analog signal from a pixel, and the second input is for receiving a time varying reference signal. The analog signal varies during a pixel readout period, and has a first level during a first reset period and a second-level during a second read period. A comparator circuit compares the time varying reference signal and the analog signal. The analog signal and the time varying reference signal are constantly read onto one of the first and second sample capacitors during both the first reset period and the second read period.

Analog to digital converter

The method and circuit corrects errors in an active pixel sensor which generates an output indicative of illumination intensity and which may experience an error in the output as a result of artifacts which produce an erroneous output. The approach includes determining the output from the pixel, comparing the output with a threshold value, and if the output is lower that the threshold value identifying the existence of an erroneous output and storing a value in a latching device in response thereto. A maximum value is generated in response to the latching device to replace the erroneous output, thereby correcting the error. The present invention switches the system from the analog to digital domain with respect to the issue of artifacts by using a latch to store a value which is then used to replace the actual output if the output is wrong.

Growing community of inventors

Forres, United Kingdom

Graeme Storm