Abstract: A device comprising: a physical unclonable function (PUF) device configured to generate an output value based on hardware characteristics of the PUF device; and a processor connected to the PUF device, the processor configured to: execute a cryptographic operation in a sequence of ordered stages including a first stage and a second stage, the executing comprising: in the first stage: recovering a first secret value based on a first output value obtained from the PUF device; executing a first sub-operation using the first secret value; and removing unobscured values from memory prior to execution of a subsequent stage; in the second stage: recovering a second secret value based on a second output value obtained from the PUF device; and executing a second sub-operation using the second secret value to enable execution of a cryptographic operation encoded with at least the first secret value and the second secret value.

Abstract: High voltage drain-extended metal-oxide-semiconductor (DEMOS) bipolar switches for electrical overstress protection are provided. In certain configurations herein, an electrical overstress switch embodiment for providing electrical overstress protection, such as electrostatic discharge/electrical overstress (ESD/EOS) protection includes both a DEMOS device and an embedded bipolar device. The switch is implemented to achieve the advantages provided by the combined conduction of DEMOS and bipolar devices. For example, the DEMOS device provides surface conduction at the gate region for relatively fast switch device turn on and low voltage overshoot, while the bipolar device provides high current conduction during stress condition and a high holding voltage characteristics to prevent latch-up in mission critical integrated circuit applications.

Abstract: A multi-input analog-to-digital converter (ADC), i.e., a single ADC, can receive multiple analog input signals and generate multiple digital outputs. To combine multiple analog input signals into a single multi-input ADC, the multi-input ADC would typically include multiple track and hold (T/H) circuits and an adder, which can consume a significant amount of power and incur large cost overhead. An improved approach is to combine multiple inputs through a unique T/H circuit in the front-end of the ADC. The multiple analog input signals can be aggregated using code sequences, without requiring a significant amount of external circuits.

Abstract: A difference amplifier circuit can be used to amplify a differential input signal representative of a current flowing through a current sensing element, such as a resistor. In certain applications, a common mode voltage established at an input of the difference amplifier circuit can be greater in magnitude than a supply voltage provided to the difference amplifier circuit. A component of the differential input signal, such as one polarity of the differential signal, can be used to power the difference amplifier circuit. Such powering of the difference amplifier by the component of the differential input signal can be performed selectively, such as when a magnitude of the common mode voltage exceeds the supply voltage or another specified threshold. In this manner, a common mode input voltage capability can be greater in magnitude than a magnitude of a supply input voltage provided to an integrated circuit including the difference amplifier circuit.

Abstract: Various embodiments provide methods of determining the quality factor of a resonating body in ways that are advantageous over previously known methods. For example, embodiments allow the determination of the quality factors of a resonating body without preventing the simultaneous use of the resonating body. For micromachined (“MEMS”) devices, embodiments allow the determination of the quality factors of a resonating body in a manner that is not dependent on transduction parameters of the MEMS device.

Abstract: Apparatus and methods for rotary traveling wave oscillators (RTWOs) are provided herein. In certain configurations, an RTWO includes a differential transmission line connected in a ring and a plurality of segments distributed around the ring. The segments include metal stubs extending from the RTWO's differential transmission line. The metal stubs aid in providing access to additional layout resources for tuning capacitors and other circuitry of the RTWO's segments, while permitting the length of RTWO's ring to be relative short. Thus, the metal stubs do not inhibit the RTWO from operating with relatively high oscillation frequency, while providing connectivity to tuning capacitors that tune the RTWO's oscillation frequency over a wide tuning range and/or provide fine frequency step size.

Abstract: Disclosed herein are two-wire communication systems and applications thereof. In some embodiments, a slave node transceiver for low latency communication may include upstream transceiver circuitry to receive a first signal transmitted over a two-wire bus from an upstream device and to provide a second signal over the two-wire bus to the upstream device; downstream transceiver circuitry to provide a third signal downstream over the two-wire bus toward a downstream device and to receive a fourth signal over the two-wire bus from the downstream device; and clock circuitry to generate a clock signal at the slave node transceiver based on a preamble of a synchronization control frame in the first signal, wherein timing of the receipt and provision of signals over the two-wire bus by the node transceiver is based on the clock signal.

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: 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: 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: 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: 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: A time-interleaved digital-to-analog converter (DAC) uses M DAC cores to convert a digital input signal whose digital input words are spread to different DAC cores to produce a final analog outputs. The M DAC cores, operating in a time-interleaved fashion, can increase the sampling rate several times compared to the sampling rate of just one DAC. However, sequential time-interleaving DAC cores often exhibit undesirable spurs at the output. To spread those spurs to the noise floor, the time-interleaving DAC cores can be selected at a pseudo randomized manner or in a specific manner which can break up the sequential or periodic manner of selecting the DAC cores.

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 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: Activity monitors and smart watches utilizing optical measurements are becoming widely popular, and users expect to get an increasingly accurate estimate of their heart rate (HR) from these devices. These devices are equipped with a light source and an optical sensor which enable estimation of HR using a technique called photoplethysmography (PPG). One of the main challenges of HR estimation using PPG is the coupling of motion into the optical PPG signal when the user is moving randomly or exercising. The present disclosure describes a computationally feasible and fast HR estimation algorithm to be executed at instances of little or no motion. Resulting HR readings may be useful on their own, or be provided to systems that monitor HR continuously to prevent the problem of such systems being locked on an incorrect HR for long periods of time. Implementing techniques described herein leads to more accurate HR measurements.

Abstract: An integrated device package is disclosed. The package can include a carrier, such as first integrated device die, and a second integrated device die stacked on the first integrated device die. The package can include a buffer layer which coats at least a portion of an exterior surface of the first integrated device die and which is disposed between the second integrated device die and the first integrated device die. The buffer layer can comprise a pattern to reduce transmission of stresses between the first integrated device die and the second integrated device die.

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).