Abstract: A circuit for sensing radiation with high sensitivity is disclosed. The circuit comprises a first transistor configurable to reset a voltage-level at a circuit node to a voltage reference. The circuit also comprises measurement circuitry configured to measure the voltage-level at the circuit node, and at least one photodiode configured to vary the voltage-level at the circuit node in response to radiation incident upon the photodiode during an integration period. The circuit also comprises processing circuitry configured to control the first transistor to reset the voltage-level at the circuit node and to subsequently configure the measurement circuitry to measure the voltage-level at a start and at an end of the integration period.

Abstract: An optical device for characterizing flicker from an ambient light source is disclosed. The device comprises a radiation-sensitive device configured to vary a current in response to incident radiation, a second or higher-order modulator configured to output data corresponding to the current, and processing circuitry configured to provide a real-time characterization of flicker in the incident radiation based upon an analysis of changes in the data. Also disclosed is an associated method of characterizing flicker from an ambient light source.

Abstract: In one embodiment an optical sensing arrangement includes a first sensor configured to provide a first sensor signal, a second sensor configured to provide a second sensor signal, an integration unit including a first input which is connected to the first sensor, a second input which is connected to the second sensor, a first output which is configured to provide a first integration signal as a function of the first sensor signal, and a second output which is configured to provide a second integration signal as a function of the second sensor signal, a comparing unit including a first input which is connected to the first output of the integration unit, a second input which is connected to the second output of the integration unit and an output configured to provide a comparison signal as a function of the first and the second integration signal, and a control unit including a first input which is coupled to the output of the comparing unit, wherein the control unit is configured to evaluate pulses of the com

Abstract: An ambient light sensor is provided that includes a sensor input having a delta-sigma analogue to digital converter. The delta-sigma analogue to digital converter includes a switched capacitor, a common mode voltage source, a reference voltage source, and a switch network. In a first clock phase, the switch network connects the switched capacitor to charge it to either a sum or difference voltage. In a second clock phase, the switch network connects the switched capacitor to transfer charge into a summing junction. A controller controls the switch network in response to a comparator output to connect the switched capacitor to either the common mode voltage or the reference voltage while in the first clock phase.

Abstract: A proximity detection system for a mobile device. The system includes an infrared emitter to emit infrared light, an infrared detector to detect the infrared light after reflection from a target and provide a detector signal; and a signal processing subsystem. The signal processing subsystem is configured to control the proximity detection system into a first, detect mode for detecting proximity of the target as the target approaches the mobile device, and after detection of the target to control the proximity detection system into a second, release mode for detecting movement of the target out of proximity to the mobile device. The signal processing subsystem also controls the proximity detection system such that, contrary to conventional hysteresis, for a given proximity of the target the detector signal reduces when the mode switches from the detect mode to the release mode, thus increasing reliability.

Abstract: An optical light sensing device includes a detector operable to detect a light wave. The optical light sensing device also includes an integration circuit that includes an operational amplifier that is operable to reduce or cancel dark currents generated at the detector.

Abstract: A switch circuit for use in a single-ended switched-capacitor circuit for front-end circuitry of a sensor device is disclosed. The switch circuit comprises a first transistor and a second transistor having a same channel-type as the first transistor. A first node is connected to a source of the first transistor and a drain of the second transistor and a second node is connected to a drain of the first transistor and a source of the second transistor. Also disclosed is a sampling circuit comprising the switch circuit and a sampling capacitor, wherein the switch circuit is configurable to electrically couple the sampling capacitor to an integrator circuit or to a voltage reference. An integrated circuit device and a light to frequency converter or light sensor comprising the switch circuit is also disclosed.

Abstract: A sensor arrangement includes a switchable voltage source having a source output for alternatively providing a first and a second excitation voltage, an integrator having an integrator input and an integrator output, a sensor resistor having a first terminal coupled to the source output, a reference resistor having a first terminal coupled to a second terminal of the sensor resistor and a second terminal coupled to the integrator input, and a comparator having a first comparator input coupled to the integrator output.

Abstract: A sensor circuit comprising a sensor input includes a delta-sigma analogue to digital converter. The delta-sigma analogue to digital converter includes a switched capacitor, a common mode voltage source, a reference voltage source, and a switch network. The switch network, in a first clock phase, connects the switched capacitor to charge it to either a sum or difference voltage, and in a second clock phase connects the switched capacitor to transfer charge into a summing junction. A controller controls the switch network responsive to a comparator output to selectively connect the switched capacitor to one of the common mode voltage and the reference voltage in the first clock phase. Implementations of the sensor circuit transfer charge every clock cycle and have low noise and high sensitivity.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for a light-to-frequency sensor conversion. In some implementations, a first output waveform is generated from a light signal, a frequency of the first output waveform being based on an intensity of the light signal, including integrating the light signal across multiple clock cycles. In response to receiving a notification, a hold operation is performed to stop integrating the light signal for a period of time. In response to an end of the hold operation, a second output waveform is generated that includes integrating the intensity of the light signal starting from the end of the hold operation over a count of the multiple clock cycles that start after the end of the hold operation by a delay amount. The first output waveform and the second output waveform are summed to determine the intensity of the light signal.

Abstract: An optical light sensing device includes a detector operable to detect a light wave. The optical light sensing device also includes an integration circuit that includes an operational amplifier that is operable to reduce or cancel dark currents generated at the detector.

Abstract: In an embodiment a method for operating a gas sensor arrangement includes generating a sensor current by a gas sensor, converting the sensor current into a digital comparator output signal in a charge balancing operation depending on a first clock signal, determining from the digital comparator output signal an asynchronous count comprising an integer number of counts depending on the first clock signal, determining from the digital comparator output signal a fractional time count depending on a second clock signal and calculating from the asynchronous count and from the fractional time count a digital output signal which is indicative of the sensor current generated by the gas sensor.

Abstract: A method for light-to-digital conversion includes setting a time integrator circuit into a reference condition and starting to integrate charge from a sensor device for the duration of an integration time. An integration signal is generated and is indicative of the integrated charge. The integration signal is compared with an adjustable reference signal. A first count is generated when the comparison indicates that the integration signal has reached an integration range, wherein the integration range is defined by a low and a high voltage. A second count is generated when the comparison indicates that the integration signal has reached the adjustable reference signal. The adjustable reference signal is incremented in discrete steps when a second count has been generated. Then, the time integrator circuit is reset into the reference condition, when the comparison indicates that the integration signal has reached the integration range.

Abstract: An apparatus includes a differential current-to-voltage conversion circuit that includes an input sampling stage circuit, a differential integration and DC signal cancellation stage circuit, and an amplification and accumulator stage circuit. An input common mode voltage of the differential current-to-voltage circuit is independent of an output common mode voltage of the differential current-to-voltage circuit.

Abstract: A sensor arrangement for light sensing for light-to-frequency conversion. The sensor arrangement includes a photodiode, an analog-to-digital converter (ADC) operable to perform a chopping technique in response to a first clock signal (CLK1), and convert a photocurrent (IPD) into a digital comparator output signal (LOUT). The ADC includes a sensor input coupled to the photodiode, an output for providing the digital comparator output signal (LOUT), an integrator including an integrator input coupled to the sensor input and operable to receive an integrator input signal, a first set of chopping switches coupled to a first amplifier, a second set of chopping switches electrically coupled to an output of the first amplifier and electrically coupled to input terminals of a second amplifier, and an integrator output providing an integrator output signal (OPOUT).

Abstract: A switch circuit for use in a single-ended switched-capacitor circuit for front-end circuitry of a sensor device is disclosed. The switch circuit comprises a first transistor and a second transistor having a same channel-type as the first transistor. A first node is connected to a source of the first transistor and a drain of the second transistor and a second node is connected to a drain of the first transistor and a source of the second transistor. Also disclosed is a sampling circuit comprising the switch circuit and a sampling capacitor, wherein the switch circuit is configurable to electrically couple the sampling capacitor to an integrator circuit or to a voltage reference. An integrated circuit device and a light to frequency converter or light sensor comprising the switch circuit is also disclosed.

Abstract: A method for light-to-frequency conversion comprises the steps of illuminating a photodiode by a light source, generating a photocurrent by means of the photodiode, converting the photocurrent into a digital comparator output signal depending on a first clock signal, generating a first count comprising an integer number of counts, where the generation of the first count depends on the first clock signal, generating a second count which relates to the time interval between at least two counts of the first count, and determining the frequency of a repeating pattern in the intensity of electromagnetic radiation emitted by the light source and detected by the photodiode from the first count and the second count. Furthermore, a light-to-frequency converter arrangement is provided.

Abstract: A sensor arrangement for light sensing for light-to-frequency conversion. The sensor arrangement includes a photodiode, an analog-to-digital converter (ADC) operable to perform a chopping technique in response to a first clock signal (CLK1), and convert a photocurrent (IPD) into a digital comparator output signal (LOUT). The ADC includes a sensor input coupled to the photodiode, an output for providing the digital comparator output signal (LOUT), an integrator including an integrator input coupled to the sensor input and operable to receive an integrator input signal, a first set of chopping switches coupled to a first amplifier, a second set of chopping switches electrically coupled to an output of the first amplifier and electrically coupled to input terminals of a second amplifier, and an integrator output providing an integrator output signal (OPOUT).

Abstract: A measurement circuitry (MC) for evaluating a resistance of a resistive gas sensor (GS) comprises a first current path (P1), wherein a first logarithmic compression circuit (LC1) is arranged in the first current path (P1). A reference resistor (Rreference) and a second logarithmic compression circuit (LC2) is arranged in a second current path (P2) of the measurement circuitry (MC). A voltage generator (VG) provides a fixed voltage excitation for the resistive gas sensor (GS) and the reference resistor (Rreference). A first current (I1) received from the resistive gas sensor (GS) flows from the gas sensor (GS) via the first current path (P1) into the first logarithmic compression circuit (LC1). An evaluation circuit (EC) determines the resistance (Rs) of the resistive gas sensor (GS) in dependence on a first and second output signal (Ve1, Ve2) of the first and the second logarithmic compression circuit (LC1, LC2).

Abstract: A temperature sensor arrangement includes a current integrating modulator that provides a count value dependent on the current supplied to its input terminal. A temperature-sensitive element includes a resistor to generate a current dependent on temperature. First and second switches alternately connect the temperature-sensitive element and another resistor to the input terminal of the current integrating modulator. The temperature sensor arrangement can be combined with an ambient light sensor sharing the current integrating modulator.