Abstract: A photon sensitive device is provided with a voltage. A controller is configured to control a voltage source so as to cause at least one calibration voltage to be applied to the photon sensitive device in a calibration mode in order to determine the voltage to be provided by the voltage source in a normal mode of operation.

Abstract: An optical navigation device for a computer application includes a radiation source capable of producing a beam of radiation, a sensor for receiving an image, and an optical element for identifying movement of the feature to thereby enable a computer action to be carried out. The optical element is formed from a single piece and includes at least one frustrated total internal reflection (F-TIR) surface capable of affecting frustrated total internal reflection of the beam of radiation in the presence of the feature to thereby generate the image.

Abstract: A method is provided for navigation of a mobile device. Spatial information of at least one beacon detected in an image relative to the image is determined. The image includes an image of the at least one beacon within at least part of an environment surrounding the mobile device. A position of the mobile device based on said spatial information is determined using encoded visual information of the at least one beacon.

Abstract: There is provided a circuit and method for detecting a bad clock condition on a clock signal that includes sampling the value of the clock signal at a first plurality of time delays following a rising edge on the clock signal. This method also includes sampling the value of the clock signal at a second plurality of time delays following a falling edge on the clock signal.

Abstract: An ambient light sensor integrated in a compact fluorescent lamp that, in turn, may include a controller and a radiation source. The ambient light sensor may include a radiation receiver to receive and filter incident radiation to obtain a value of the level of infrared radiation, and an electronic module to determine if the value is above a reference threshold value to enable the controller to switch the state of the radiation source.

Abstract: An apparatus is provided that comprises a test circuit; a first receiver unit arranged to receive test commands and to provide the test commands to the test circuit; a power supply unit arranged to supply power to the test circuit and to the first receiver unit; a second receiver unit arranged to receive power commands. The second receiver is arranged to control the operation of the power supply unit in response to the power commands received by the second receiver unit.

Abstract: A deep SPAD structure uses the substrate as the anode terminal of its multiplication p-n junction. A bias voltage for the SPAD (in excess of the SPAD's breakdown voltage) is coupled to the SPAD's cathode terminal. The bias voltage is generated by a charge pump circuit which is also integrated on the substrate. The charge pump circuit is configured to isolate the bias voltage on the cathode terminal. A triple well CMOS process is used to isolate the transistors of the charge pump circuit from the substrate.

Abstract: 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.

Abstract: A request routing circuit includes m inputs for receiving m input request signals and n outputs for outputting a set of n output request signals. A routing subsystem within the request routing circuit is provided between the m inputs and the n outputs and comprises k inputs and n outputs, where m is greater than k, and where the routing subsystem is configured to operate over a plurality (m/k, rounded up to the next integer) of cycles to provide the set of n output request signals based on the m inputs to the n outputs.

Abstract: This invention relates to a method of receiving a first potentially unreliable clock signal having a first frequency; receiving a second reliable clock signal having a second frequency; wherein the first frequency and the second frequency have an expected relationship; determining whether the first potentially unreliable clock signal has changed with respect to the second reliable clock signal by: determining an actual relationship between the first potentially unreliable frequency and the second reliable frequency; and generating an alarm signal if the actual relationship is different to the expected relationship.

Abstract: Disclosed is an output stage, and associated apparatus, for a voltage regulator that includes a clamp circuit that is operable to ensure that the output voltage recovers quickly, i.e. that the perturbation of this voltage is limited and remains within a given specification, when entering a standby mode and which is controlled in a supply independent manner.

Abstract: A sporting device may include a proximity detector, and a housing for carrying the proximity detector. The proximity detector may comprise a single photon avalanche diode for measuring the speed of an object struck by the housing. For example, the housing may define a tennis racket.

Abstract: A proximity sensor includes a sensor package having an attachment pad with a radiation source and a radiation detector housed within the sensor package. The source and the detector are held in a fixed relation to the attachment pad, and are mounted by one of a direct or indirect attachment to the attachment pad. A portion of the attachment pad is adapted to form a baffle which forms at least part of an optical isolator. The optical isolator is adapted to substantially prevent the internal propagation of radiation between the source and the detector within the sensor package.

Abstract: An image sensor has a pixel array and an input circuit. The input circuit includes a first input, a second input and two coupling capacitors. The first input receives an analog signal from a pixel of the pixel array which has a first level during a first calibration period and a second level during a second read period. The second input receives a reference ramp signal. A comparator circuit compares the ramp signal and the analog signal. The analog signal and the ramp signal are constantly read onto the coupling capacitors during both the first calibration period and the second read period. The ramp circuit begins providing the ramp signal during the second read period so as to determine the change in magnitude of the analog signal between the first calibration period and the second read period, the ramp circuit also begins providing the ramp signal during the first calibration period so as to compensate for any delay in the ramp circuit providing the ramp signal during the second read period.

Abstract: A semiconductor integrated circuit includes a hardware mechanism arranged to ensure that associations between instructions and data are enforced so that a processor cannot fetch data from an instruction that is not authorized to do so. A Memory Protection Unit stores entries comprising instructions and associated data memory ranges. A hardware arrangement impairs the operation of the circuit if the processor attempts to make a data fetch from an instruction that is outside the range associated with data in a Memory Protection Unit. Such functioning may be by issuing a chip reset. The Memory Protection Unit may be implemented in a Memory Management Unit having an extension so as to store a validity flag. The validity flag may only be set by a secure process such as the CPU well entrusted code or by a separate trusted hardware source.

Abstract: A circuit receives a parameter signal at a set or reset input, a clock signal at a clock input and a constant digital value at a data input. A synchronous signal is output from the circuit: wherein when the parameter signal is in a first state, then the output synchronous signal has the digital value; wherein when the parameter signal transitions to a second state, then the output synchronous signal transitions to an inverse of the digital value at substantially the same time; and wherein when the parameter signal transitions back to the first state, then the output synchronous signal transitions to the digital value on a next clock edge.

Abstract: A touch pad uses a plurality of optical mouse type sensors. The sensors are optimized for detection of motion along the predominant direction of a user's finger as the finger is moved around the touch pad. A first one of the sensors functions to optically sense motion in a first direction, while a second one of the sensors functions to optically sense motion in a second, different, direction. The first and second directions are oriented a closed, for example, circular, path.

Abstract: Systems and methods are disclosed for pre-fetching data into a cache memory system. These systems and methods comprise retrieving a portion of data from a system memory and storing a copy of the retrieved portion of data in a cache memory. These systems and methods further comprise monitoring data that has been placed into pre-fetch memory.

Abstract: A pixel circuit includes a single photon avalanche diode (SPAD) and a measurement circuit including a capacitance. The SPAD detects an incident photon and the measurement circuit discharges the capacitance at a known rate during a discharge time period. The length of the discharge time period is determined by the time of detection of the photon, such that the final amount of charge on the capacitance corresponds to the time of flight of the photon. The pixel circuit may be included in a time resolved imaging apparatus. A method of measuring the time of flight of a photon includes responding to an incident photon detection by discharging a capacitance at a known rate and correlating final capacitance charge to time of flight.

Abstract: A pixel circuit includes a single photon avalanche diode (SPAD) and a measurement circuit including a capacitance. The circuit is operable to discharge a known portion of the charge on the capacitance upon each detection of a SPAD event within a time period, such that the charge remaining on the capacitance at the end of the time period corresponds to the number of SPAD events detected within the time period. A time resolved imaging apparatus includes an array of such pixel circuits. A method of counting photon detection includes sensing photons with a SPAD device and discharging a known portion of the charge on a capacitance upon each detection of a SPAD event within a time period.