Abstract: A MEMS resonant accelerometer includes two proof masses configured to resonate when driven with periodic signals. Each proof mass includes a resonator structure that vibrates relative to the proof mass and a dummy structure that does not resonate. When driven by a periodic drive signal, the resonator structures of the two proof masses may be used to determine the magnitude of acceleration in the direction perpendicular to the planes of the proof masses by sensing the frequency at which the resonators vibrate. For example, a differential oscillation frequency may be computed from the two sensed frequencies. The dummy structures are used to make the mass distribution of the two proof masses similar.

Abstract: An example current mirror arrangement includes a first portion and a second portion, each of which includes a current mirror having transistors Q1 and Q2, a buffer amplifier that has an input coupled to a base/gate terminal of Q1 and an output coupled to a base/gate terminal of Q2, a master resistor coupled to an emitter/source terminal of Q1, and a slave resistor coupled to an emitter/source terminal of Q2. Furthermore, the slave resistor of the first portion is coupled to the slave resistor of the second portion. Providing additional resistors on master and slave sides of a current mirror arrangement may advantageously allow benefiting from the use of buffers outside of a feedback loop of a current mirror while reducing the sensitivity of the current mirror arrangement to buffer offsets.

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: An integrated gesture sensor module includes an optical sensor die, an application-specific integrated circuit (ASIC) die, and an optical emitter die disposed in a single package. The optical sensor die and ASIC die can be disposed in a first cavity of the package, and the optical emitter die can be disposed in a second cavity of the package. The second cavity can be conical or step-shaped so that the opening defining the cavity increases with distance from the upper surface of the optical emitter die. The upper surface of the optical emitter die may be higher than the upper surface of the optical sensor die. An optical barrier positioned between the first and second cavities can include a portion of a pre-molded, laminate, or ceramic package, molding compound, and/or metallized vias.

Abstract: Optical systems can emit train(s) of light pulses onto objects to derive a distance between the light source and the object. Achieving meter or centimeter resolution may require very short light pulses. It is not trivial to design a circuit that can generate narrow current pulses for driving a diode that emits the light pulses. An improved driver circuit has a pre-charge path comprising one or more inductive elements and a fire path comprising the diode. Switches in the driver circuit are controlled with predefined states during different intervals to pre-charge current in the one or more inductive elements prior to flowing current through the fire path to pulse the diode.

Abstract: Disclosed herein are systems and techniques for serial peripheral interface (SPI) functionality for node transceivers in a two-wire communication bus. For example, in some embodiments, a node transceiver may include SPI circuitry and upstream or downstream transceiver circuitry. SPI commands received via the SPI circuitry may be executed by the node transceiver, or transmitted upstream or downstream along the two-wire bus for execution by another node transceiver or a slave device coupled to another node transceiver.

Abstract: Microelectromechanical system (MEMS) inertial sensors exhibiting reduced parasitic capacitance are described. The reduction in the parasitic capacitance may be achieved by forming localized regions of thick dielectric material. These localized regions may be formed inside trenches. Formation of trenches enables an increase in the vertical separation between a sense capacitor and the substrate, thereby reducing the parasitic capacitance in this region. The stationary electrode of the sense capacitor may be placed between the proof mass and the trench. The trench may be filled with a dielectric material. Part of the trench may be filled with air, in some circumstances, thereby further reducing the parasitic capacitance. These MEMS inertial sensors may serve, among other types of inertial sensors, as accelerometers and/or gyroscopes. Fabrication of these trenches may involve lateral oxidation, whereby columns of semiconductor material are oxidized.

Abstract: Single-axis teeter-totter accelerometers having a plurality of anchors are disclosed. The plurality of anchors may be arranged about a rotation axis of the teeter-totter proof mass. Each of the plurality of anchors may be coupled to the proof mass by two torsional springs each extending along the rotation axis. The plurality of anchors allows an increased number of torsional springs to be coupled to the proof mass and thus greater torsional stiffness for the proof mass may be achieved. Due to the higher torsional stiffness, the disclosed single-axis teeter-totter accelerometers may be deployed in high-frequency environments where such increased torsional stiffness is required, for example, around 20 kHz and above.

Abstract: Herein disclosed are approaches for protecting sensitive information within a fingerprint authentication system that can be snooped and utilized to access the device, secured information, or a secured application. The approaches can utilize encryption keys and hash functions that are unique to the device in which the fingerprint authentication is being performed to protect the sensitive information that can be snooped.

Abstract: There is disclosed in one example an audio processor, including: an audio crossover to separate a first frequency band from a second frequency band, the first frequency band having a lower frequency band than the second frequency band; an excursion estimator to estimate from information of the first frequency band a predicted excursion of a low-frequency driver; an interpolator to interpolate an adjustment to the second frequency band to compensate for the estimated excursion; and circuitry to drive the adjusted second frequency to a receiver.

Abstract: Improved track and hold (T/H) circuits can help analog-to-digital converters (ADCs) achieve higher performance and lower power consumption. The improved T/H circuits can drive high speed and interleaved ADCs, and the design of the circuits enable additive and multiplicative pseudo-random dither signals to be injected in the T/H circuits. The dither signals can be used to calibrate (e.g., linearize) the T/H circuits and the ADC(s). In addition, the dither signal can be used to dither any remaining non-linearity, and to calibrate offset/gain mismatches in interleaved ADCs. The T/H circuit design also can integrate an amplifier in the T/H circuit, which can be used to improve the signal-to-noise ratio (SNR) of the ADC or to act as a variable gain amplifier (VGA) in front of the ADC.

Abstract: Disclosed herein are systems and techniques for general purpose input/output (GPIO)-to-GPIO communication in a multi-node, daisy-chained network. In some embodiments, a transceiver may support GPIO between multiple nodes, without host intervention after initial programming. In some such embodiments, the host may be required only for initial setup of the virtual ports. In some embodiments, GPIO pins can be inputs (which may change virtual ports) or outputs (which may reflect virtual ports). In some embodiments, multiple virtual ports may be mapped to one GPIO output pin (with the values OR'ed together, for example). In some embodiments, multiple GPIO input pins may be mapped to one virtual port. For example, multiple GPIO input pin values may be OR'ed together, even if they come from multiple nodes.

Abstract: System and apparatus for portable gas detection. Specifically, this disclosure describes apparatuses and systems for optical gas detection in a compact package. There is a need for a very compact, low-power, gas detection system for gases such as CO2, NOx, water vapor, methane etc. This disclosure provides an ultra-compact and highly efficient optical measurement system based on principals of optical absorption spectroscopy. It reduces the size of the instrument as well its power consumption by more than an order of magnitude making it possible to deploy it widely. There is an identified need for large number of distributed gas sensors to improve human health, environment, and save energy usage.

Abstract: Device for improving an optical detecting smoke apparatus and implementing thereof. Apparatus and methods for detecting the presence of smoke in a small, long-lasting smoke detector are disclosed. Specifically, the present disclosure shows how to build one or more optimized blocking members in a smoke detector to augment signal to noise ratio. This is performed while keeping the reflections from the housing structure to a very low value while satisfying all the other peripheral needs of fast response to smoke and preventing ambient light. This allows very small measurements of light scattering of the smoke particles to be reliable in a device resistant to the negative effects of dust. In particular, geometrical optical elements, e.g., cap and optical defection elements, are disclosed.

Abstract: The signal strength of a vector modulator based phase shifter can be increased enabling signals to be received or transmitted over larger distances than existing phase shifters by applying multiple weights to components of a signal. An input signal can be divided into orthogonal components that can be weighted and combined to generate an intermediate signal. A second intermediate signal can be generated by applying complementary weights to the orthogonal component signal. The two intermediate signals can be combined to obtain the phase shifted signal. By combining complementary weighted component signals, a phase shifted signal with improved signal to noise ratio and greater signal strength can be generated.

Abstract: In certain configurations, an input/output (IO) interface of a semiconductor chip includes a pin, an interface switch connected to the pin, and an overstress detection and active control circuit that controls a resistance of the interface switch with active feedback. The overstress detection and active control circuit increases a resistance of the interface switch in response to detection of a transient overstress event between a first node and a second node. Accordingly, the overstress detection and active control circuit provides separate detection and logic control to selectively modify the resistance of the interface switch such that the interface switch operates with low resistance during normal operating conditions and with high resistance during overstress conditions.

Abstract: A method for detecting frequency mismatch in microelectromechanical systems (MEMS) gyroscopes is described. Detection of the frequency mismatch between a drive signal and a sense signal may be performed by generating an output signal whose spectrum reflects the physical characteristics of the gyroscope, and using the output signal to determine the frequency fC of the sense signal. The output signal may be generated by cross-correlating a random or pseudo-random noise signal with a response signal, where the response signal can be obtained by allowing the noise signal to pass through a system designed to have a noise transfer function that mimics the frequency response of the gyroscope. Since the noise signal is random or pseudo-random, cross-correlating the noise signal with the response signal reveals spectral characteristics of the gyroscope. To improve computational efficiency, the cross-correlation can be performed on demodulated versions of the noise signal and the response signal.

Abstract: A state of one or more fuses can be determined using a common-gate FET device to read reference information and test information from a fuse bank. In an example, the FET device can be selectively diode-connected using a first switch that responds to a control signal, and a signal-storing capacitor can be connected to the gate terminal of the FET device. The capacitor can store information about a reference signal when the first switch is closed and a first input signal is applied at a source node of the FET device. When the first switch is open, a second input signal can be applied at the source node of the FET device, and an output signal at the drain node of the FET device can indicate a magnitude relationship between the first input signal and the reference signal. In an example, the second input signal can indicate a state of a fuse.

Abstract: Disclosed herein are systems and techniques for auxiliary master and/or auxiliary call support functionality. For example, in some embodiments, a communication system with auxiliary master functionality may include a master node coupled to a plurality of downstream slave nodes, wherein at least one of the slave nodes may perform master node functions when the master node is disconnected from the system.