Abstract: Systems and methods for transferring power across an isolation barrier using an active self-synchronized rectifier are described. A rectifier as described herein may provide DC to DC power conversion with high efficiency. Furthermore, by using a microfabricated transformer or microfabricated capacitor as an isolation component, an isolation component and rectifier may be microfabricated and implemented on chip.

Abstract: Comparators are implemented in many circuits, including analog-to-digital converters (ADCs). Some ADCs demand high bandwidth, low power consumption, and high speed. To address these requirements, a comparator circuit can be implemented without a separate pre-amplifier, where a sampling network drives a latch directly. Specifically, the comparator circuit integrates a pre-amplifier within the latch in a manner that ensures low power and high speed operation.

Abstract: Systems and methods for transferring power across an isolation barrier using an active self-synchronized resonator are described. A resonator may use the isolation barrier to resonate with active devices arranged on both sides of the barrier, to provide DC to DC power conversion with high efficiency. Furthermore, by using a microfabricated transformer or microfabricated capacitor as an isolator, the entire resonator may be microfabricated and implemented on chip. The resonator is also bidirectional, allowing power transfer in either direction across the isolation barrier.

Abstract: Vital sign monitors are plagued by noisy photoplethysmography (PPG) data, making it difficult for the monitors to output consistently accurate readings. Noise in PPG signals is often caused by motion. The present disclosure provides improved techniques for reducing motion-related artifacts in optical/PPG measurements for vital signs monitoring. In general, techniques described herein are based on using measurements of reference sensors that include sensors other than optical sensors used for the optical measurements, e.g., biopotential sensors, bioimpedance sensors, and/or capacitive sensors. In particular, techniques described herein aim to filter PPG signals using substantially only the noise components of signals generated by reference sensors, by attenuating or altogether eliminating components of the signals generated by reference sensors which are indicative of the parameter the reference sensors are designed to measure.

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: Amplifier systems for driving a wide range of loads are provided herein. In certain embodiments, an amplifier system includes a voltage output amplifier and a current output amplifier that are electrically coupled in parallel with one another between an input terminal and an output terminal. The amplifier system further includes a control circuit operable to control whether or not the voltage output amplifier and/or current output amplifier drive the output terminal.

Abstract: An image processing system for time-of-flight depth imaging includes a processor for determining depth measurements using different modes of operation. The processor determines depth measurements in a first set of frames using a second set of frames. The first mode is a continuous wave modulation mode without depth linearization and the second mode is a continuous wave modulation mode with depth linearization. The depth estimates collected in the second mode using depth linearization are used to correct the depth estimates collected in the first mode.

Abstract: Time of Flight (ToF) image processing methods include collecting correlation samples to calculate a phase estimate. Systems and methods are provided for collecting correlation samples from multiple pixels. An image processing system for continuous waves includes a light source configured to emit light, an image sensor having a plurality of pixels, and a processor configured to collect correlation samples from a subset of the plurality of pixels in the image sensor.

Abstract: Time of Flight (ToF) image processing systems and methods for proximity detection are disclosed. In particular, use of a separate proximity detector can be eliminated by using the time of flight image processing system as disclosed herein. In particular, the time of flight image processing system has two modes: a low resolution proximity detection mode and a high resolution imaging mode.

Abstract: Apparatus and methods for clock synchronization and frequency translation are provided herein. Clock synchronization and frequency translation integrated circuits (ICs) generate one or more output clock signals having a controlled timing relationship with respect to one or more reference signals. The teachings herein provide a number of improvements to clock synchronization and frequency translation ICs, including, but not limited to, reduction of system clock error, reduced variation in clock propagation delay, lower latency monitoring of reference signals, precision timing distribution and recovery, extrapolation of timing events for enhanced phase-locked loop (PLL) update rate, fast PLL locking, improved reference signal phase shift detection, enhanced phase offset detection between reference signals, and/or alignment to phase information lost in decimation.

Abstract: Disclosed herein are systems and methods for performing DC offset correction of a video signal received over an AC-coupled video link. In one aspect, a transmitter is configured to compute, and provide to a receiver, metadata indicative of a statistical characteristic (e.g., an average or a sum of values) for a group of active pixels of a video signal acquired by a camera. The receiver is configured to compute an analogous statistical characteristic on the video signal received over an AC-coupled video link, and to perform DC offset correction by modifying one or more values of the received video signal based on a comparison of the statistical characteristic computed by the receiver and the one computed by the transmitter and indicated by the received metadata.

Abstract: A microfluidic ion detector for detecting heavy metal ions in liquid and particulate matter from gas samples is described. The microfluidic ion detector includes a sample extraction structure for extracting sample ions from a sample liquid or extracting sample ions from the particulate matter of a gas sample, a separation structure for separating sample ions of different types once extracted, and a detection structure for detecting the sample ions. The microfluidic ion detector also includes a reference reservoir providing a reference ion against which the sample may be calibrated based on the operation of the separation structure. A portable, self-calibrating ion detector may be realized by including the described components on a single substrate.

Abstract: This application describes systems and methods for using a physical unclonable function (PUF) to authenticate a device, which may include circuitry for generating PUF values that may uniquely identify the device. According to one aspect, the device may provide enrollment PUF values to an authentication device. The device may later be authenticated if PUF values generated by the device are within a threshold distance of the enrollment PUF values. Since the PUF values are compared using a distance, it may not necessary to apply an error correcting code to the PUF values. The enrollment values and/or the calculated distance may be adjusted to compensate for time variations in the PUF values due to circuit aging. Systems and methods are also described herein for authenticating the device without revealing new PUF values to any second party, for example using a cryptographic technique known as a garbled circuit.

Abstract: Apparatus and methods for clock synchronization and frequency translation are provided herein. Clock synchronization and frequency translation integrated circuits (ICs) generate one or more output clock signals having a controlled timing relationship with respect to one or more reference signals. The teachings herein provide a number of improvements to clock synchronization and frequency translation ICs, including, but not limited to, reduction of system clock error, reduced variation in clock propagation delay, lower latency monitoring of reference signals, precision timing distribution and recovery, extrapolation of timing events for enhanced phase-locked loop (PLL) update rate, fast PLL locking, improved reference signal phase shift detection, enhanced phase offset detection between reference signals, and/or alignment to phase information lost in decimation.

Abstract: Novel structural features applicable to a variety of inertial sensors. A composite ring composed of concentric subrings is supported by a compliant support structure suspending the composite ring relative to a substrate. The compliant support structure may either be interior or exterior to the composite ring. The compliant support may be composed of multiple substantially concentric rings coupled to neighboring rings by transverse members regularly spaced at intervals that vary with radius relative to a central axis of symmetry. Subrings making up the composite ring may vary in width so as to provide larger displacement amplitudes at intermediate radii, for example. In other embodiments, electrodes are arranged to reduce sensitivity to vibration and temperature, and shock stops are provided to preclude shorting in response to shocks.

Abstract: A demodulator for pulse-width modulated clock signals is disclosed. In one aspect, the demodulator includes an edge detector configured to detect transitions in a reference clock and output a signal indicative of timing of the detected transitions. The demodulator may also include a modulation detection circuit configured to identify modulation events of at least one pulse-width modulated pulse in the reference clock based on the signal output from the edge detector and output a signal indicative of the at least one pulse-width modulated pulse modulation event being identified. The demodulator may further include a retiming circuit configured to generate an output clock synchronized with the at least one pulse-width modulated pulse modulation event based on the signal output from the modulation detection circuit.

Abstract: Embodiments of the disclosure provide various nanogap sensor designs (e.g., horizontal nanogap sensors, vertical nanogap sensors, arrays of multiple nanogap sensors, various arrangements for making electrical connections to the electrodes of nanogap sensors, etc.), as well as various methods which may be used to fabricate at least some of the proposed sensors. The nanogap sensors proposed herein may operate as molecular sensors to help identify chemical species through electrical measurements using at least a pair of electrodes separated by a nanogap.

Abstract: There is disclosed herein examples of systems and methods for compressing a signal. Samples of the signal can be segmented and the samples within each of the segments can be averaged to produce a value that can represent the samples within the segment. The number of samples to average in each segment may be determined based on an error threshold, such that the number of samples being averaged can be maximized to produce less data to be transmitted while maintaining the representation of the samples within the error threshold. In some embodiments, a signal can be separated into a timing reference, a representative periodic function, and a highly compressible error signal. The error signal can be utilized for reproducing a representation of the signal.

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: A magnetic field sensor is disclosed. The magnetic field sensor includes a first magnetoresistive element and a second magnetoresistive element arranged as a half bridge. The magnetic field sensor also includes two or more conductors adjacent to the first magnetoresistive element and the second magnetoresistive element. The two or more conductors can carry a bias current and a compensation current such that the bias current and the compensation current flow in the same direction adjacent to the first magnetoresistive element while the bias current and the compensation current flow in opposite directions adjacent to the second magnetoresistive element.