Abstract: This application discusses techniques for providing a power-on reset (POR) circuit. The techniques take advantage of the small size of active devices, consume very little current and can use a native NMOS transistor to provide a stable reference over temperature and voltage variations.

Abstract: Sensor error detection with an additional channel is disclosed herein. First and second magnetic sensing elements can be disposed at angles relative to each other. In some embodiments, the first and second magnetic sensing elements can be magnetoresistive sensing elements, such as anisotropic magnetoresistance (AMR) sensing elements. Sensor data from first and second channels, respectively, having the first and second sensing elements, can be obtained. Third channel can receive a signal from the first sensing element and a signal from the second sensing element, and sensor data from the third channel can be obtained. Expected third channel data can be determined and compared to the obtained third channel data to indicate error.

Abstract: Aspects of this disclosure relate to adjusting a phase of a clock signal provided to a device based on a feedback signal from the device. The feedback signal can provide phase information associated with the device and/or other information associated with the device, such as temperature information. A feedback signal processor can compute a phase control signal based on the feedback signal. The phase control signal can be used to adjust the phase of the clock signal. By adjusting the phase of one or more clock signals, several devices, such as data converters, can be synchronized.

Abstract: This application discusses techniques for reducing the energy of an output ripple in a voltage converter at a switching frequency of the voltage converter. In certain examples, an amplitude of a reference voltage can be modulated with a time-varying random value or pseudo-random value to provide a reduction in the energy of the output ripple at the switching frequency of the voltage converter.

Abstract: Capped microelectromechanical systems (MEMS) devices are described. In at least some situations, the MEMS device includes one or more masses which move. The cap may include a stopper which damps motion of the one or more movable masses. In at least some situations, the stopper damps motion of one of the masses but not another mass.

Abstract: According to various aspects, a delay-based physical unclonable function (PUF) device is provided. According to one embodiment, the PUF device includes circuitry for generating output bits of entropy by comparing, or “racing”,” a plurality of PUF cells. A PUF cell is a building block of the PUF device. For example, the PUF device may include two identically designed circuits with only process related variations and each circuit can be a PUF cell. According to another aspect, if PUF cells with same history of winning or losing are being compared in a race, adversaries cannot predict the outcome of the current race based on previous race results. Accordingly, systems and methods are described herein for generating multiple rounds of races based on the previous rounds of races. Thus, one PUF cell can be used in multiple pairwise comparisons while maximal entropy is extracted.

Abstract: Device for detecting characteristic signals of tissues and materials and methods for calculating thereof. Apparatus and methods for detecting the presence of tissue (skin) in pulse oximeter are disclosed. Specifically, analysis using optical techniques are used to identify characteristic signals of different compositions of matter. The present application discloses using a plurality of photodetectors at different distances from a source to measure light scattering through a variety of materials, and more specifically, to detect the presence of tissue.

Abstract: A microelectromechanical system (MEMS) apparatus is described. The MEMS apparatus may comprise inertial sensors and energy harvesters configured to convert mechanical vibrational energy into electric energy. The harvested energy may be used to power an electronic circuit, such as the circuit used to sense acceleration from the inertial sensors. The inertial sensors and the energy harvesters may be disposed on the same substrate, and may share the same proof mass. The energy harvesters may include a piezoelectric material layers disposed on a flexible structure. When the flexible structures flexes in response to vibration, stress arises in the piezoelectric material layer, which leads to the generation of electricity. Examples of inertial sensors include accelerometers and gyroscopes.

Abstract: An analog front end system can include a filter bypass switch connected in a boot-strapped configuration to pull a control terminal of the filter bypass switch above or below a supply voltage. Using bootstrapped switches can allow both the charge injection and capacitive coupling of the bypass switches of a differential anti-alias filter (AAF) to be common mode. A differential input signal of the ADC is not affected by the charge injection and capacitive coupling of the bypass switches in the AAF filter to a first order.

Abstract: Power amplifier circuits can behave in a non-linear manner particularly when operated to produce output signal swings approaching an amplifier saturation region. A pre-distortion signal can be applied to a signal to be transmitted to compensate for such power amplifier non-linearity. In applications where two or more transmitter power amplifiers are used, a beam-former can be configured to modify a digitally pre-distorted transmission signal by applying respective beam-forming weighting factors to the digitally pre-distorted transmission signal to provide input transmission signals for respective ones of the power amplifier circuits. The pre-distortion signal can be established at least in part using one or more of a sensed or estimated representation of a transmitted beam formed by spatially aggregating transmitted outputs from the two or more power amplifier circuits.

Abstract: A chip includes a phase-locked loop (PLL) and a test controller. The PLL includes an oscillator and a phase detector. In a normal mode, a first feedback loop includes a phase detector and an oscillator that generates an output based on a frequency input signal. In a test mode, the PLL is re-configured. The output of the loop filter can be decoupled from the input of the oscillator in the test mode and instead be coupled to the input of the phase detector. The oscillator can receive a test tuning signal provided by the test controller. In this test mode configuration, the PLL can measure the frequency of the oscillator.

Abstract: An analog-to-digital converter (ADC) circuit comprises a first digital-to-analog (DAC) circuit and a second DAC circuit, wherein the first and second DAC circuits include weighted bit capacitors and reservoir capacitors; a sampling circuit configured to sample a differential input voltage onto the weighted bit capacitors and to sample a reference voltage onto the reservoir capacitors; a comparator circuit operatively coupled to outputs of the first and DAC circuits; and logic circuitry configured to: initiate successive bit trials of weighted bit capacitors to convert the input voltage to a digital value by comparing an output of the first DAC circuit and an output of second DAC circuit using the comparator circuit; and apply charge of the reservoir capacitors to the bit capacitors to reduce the comparator differential input voltage and reduce an error between the input common mode offset and the comparator common mode offset.

Abstract: A electrochemical or other sensor interface circuit architecture can deliver substantial DC offset bias to an electrochemical or other sensor separately or independently from delivering a time-varying AC excitation signal, which can then be provided with higher resolution, which, in turn, can allow better resolution of the measured response signal providing the impedance characteristic of sensor condition. For example, a differential time-varying AC excitation signal for the sensor condition characteristic can be delivered separately and independently from a differential stable (e.g., DC or other) bias signal, such as by using separate digital-to-analog converters (DACs), so that providing the more stable signal does not limit the resolution and accuracy of the time-varying signal, such as by using up the dynamic range of a single DAC.

Abstract: A programmable resistor can provide discrete logarithmic (linear-in-dB) gain control. It can include multiple like programmable resistor subnetworks or cells, such as can be connected in parallel, such as according to a decoding scheme. The subnetworks can be configured to cover a subrange such as [0 dB, ?6 dB) relative to the maximum resistance value. Coarse increments of ?6 dB can be further added to this range by successively doubling the number of subnetworks that are connected in parallel. An additional decoder help ensure a linear control curve, free of dead zones or other nonlinearities. The programmable resistor can be suitable for use in such circuits as programmable-gain amplifiers, filters, or more complex networks, such as where the resistance can be programmed as a function of a digital code. An example including a tuning circuit for a variable gain active filter is described.

Abstract: An integrated ion-sensitive probe is provided. In an example, an ion-sensitive probe can include a semiconductor substrate and a first passive electrode attached to the semiconductor substrate. The first passive electrode can be configured to contact a solution and to provide a first electrical voltage as function of a concentration of an ion within the solution. In certain examples, a passive reference electrode can be co-located on the semiconductor substrate. In some examples, processing electronics can be integrated on the semiconductor substrate.

Abstract: Clock systems with phase noise compensation are provided herein. In certain implementations, a clock system includes a phase noise detector for detecting a phase noise of a clock signal, and an adjustable delay circuit for generating an adjusted clock signal based on delaying the clock signal with a controllable delay. Additionally, the phase noise detector generates an error signal indicated the phase noise of the clock signal, and controls the delay of the adjustable delay circuit with the error signal over time to thereby compensate the clock signal for phase noise. Thus, the adjusted clock signal has reduced phase noise compared to the clock signal.

Abstract: System and techniques for an occupancy sensor are described herein. Images from a camera can be received. Here, the camera has a certain a field of view. A proximity indicator from a proximity detector can be received when an object enters the field of view. The images from the camera are processed to provide an occupancy indication. A first technique is used for the occupancy indication in the absence of the proximity indicator and a second technique is used otherwise.

Abstract: Integrated digital isolators comprise a first transformer coil or capacitor plate mounted on an integrated circuit substrate, and separated from a second transformer coil or capacitor plate via an electrically insulating isolation layer. The electrical isolation that is achieved is dependent upon the material and thickness of the isolation layer. In order to reduce the amount of time required for fabrication while still allowing thick isolation layers to be deployed, in examples of the disclosure pre-formed sheets or tapes of dielectric material are applied to the substrate over the first transformer coil or capacitive plate, for example by being rolled onto the substrate using a heated roller. Such a technique results in a thick isolation layer that is formed using a simple process and much more quickly and reliably than conventional spin-coating or deposition techniques.

Abstract: As a PUF device ages, the response characteristics of the device change. Thus, mappings made on the original PUF outputs can drift and become invalid. Re-enrollment or re-mapping of hidden values to PUF response characteristics can resolve the changing nature of the PUF. Unfortunately, an adversary may tamper with the PUF during re-enrollment compromising security of the PUF. Accordingly, techniques of securely and remotely re-enrolling a PUF device are described. During an initial enrollment of the PUF device, multiple sets of enrollment values of the PUF device can be generated. For remote re-enrollment, a first initial set of enrollment values can be used to authenticate the PUF device. Upon authentication using the first initial set, the PUF device can re-enroll the PUF device and account for changes in PUF characteristics. A second set of initial enrollment values can then be used to verify that the PUF device is unaltered.

Abstract: Some or all of a comparator circuit of an analog-to-digital converter (ADC) circuit can be efficiently repurposed or reused for residue amplification for efficient noise-shaping, e.g., in a noise-shaping feedback configuration. A preamplifier portion of a comparator circuit in an oversampling ADC can be re-purposed to provide an amplifier to amplify or otherwise modify a residue left after the bit trials of a conversion cycle. The amplified or modified residue can then be used elsewhere, for example, for noise-shaping by applying a noise transfer function (NTF), a result of which can then be fed back (e.g., summed with the next sampled input at an input of the comparator circuit for use in the N bit trials of the next ADC cycle).