Analog Devices,inc.

Analog Devices International Unlimited Company

Other

Ronald Alan Kapusta

Junhua Shen

Jiefeng Yan

James Lin

Shawn S Kuo

Jianrong Chen

Haiyang Zhu

Mark D Maddox

Youn-Jae Kook

Doris Lin

Jonathan Ephraim David Hurwitz

Colin Gerard Lyden

William Albert Clark

Eoin Edward English

Javier Calpe Maravilla

Scott Robert Davis

Andrew William Sparks

Tyler Adam Dunn

Erik D Barnes

Edward Chapin Guthrie

Leonard Shtargot

Michael Ziemkiewicz

Eugene Cheung

Jose Barreiro Silva

Brian D Hamilton

Daniel Peter Canniff

Paul O'Sullivan

Jonathan Paolucci

Katsu Nakamura

Maurizio Zecchini

Mark T Sayuk

Krystian Balicki

Xu Tang

Lijun Gao

Monica Redon Segrera

Yervant Dermenjian

Mark Sayuk

A method for determining, in an optical detection system, a distance to a target region includes obtaining first and second light pulses from a signal generator within the optical detection system and obtaining samples of the respective first and second light pulses, where the samples having a first temporal resolution. The method also includes generating a reference waveform having a second temporal resolution by combining the samples of the respective first and second light pulses, where the second temporal resolution being higher than the first temporal resolution. The method further includes obtaining a reflection of a third light pulse from the target region and determining an arrival time of the reflection of the third light pulse using the reference waveform.

LIDAR reference waveform with increased sample rate

The present disclosure provides designs and techniques to improve turn 'off' times of a bootstrapped switch, maximizing the total 'on' time of the bootstrapped switch. The techniques described herein provide a protection device coupled to the bootstrapped switch. The protection device may be controlled by an input voltage to the bootstrapped switch during a boosting phase and may be controlled by a constant voltage during a non-boosting phase. The techniques for reducing turn &#x201c;off&#x201d; times are particularly useful in high-speed applications, such as high-speed, low-voltage analog-to-digital converters.

Bootstrapped switch with fast turn off

In an optical detection system, features of interest can be identified from ADC circuitry data prior to inter-circuit communication with downstream object or target processing circuitry. In this manner, a volume of data being transferred to such downstream processing circuitry can be reduced as compared to other approaches, simplifying the receive signal processing chain and providing power savings. First-tier signal processing circuitry to identify features of interest can be located on or within a commonly-shared integrated circuit package with ADC circuitry, and downstream processing circuitry for object processing or range estimation can be fed with a data link meeting less stringent requirements than a link between the ADC circuitry and first-tier signal processing circuitry.

Data reduction for optical detection

This disclosure is directed to, among other things, techniques to quickly replenish a capacitance of a laser diode driver circuit after an optical pulse, which can enable a burst of pulses (more than one pulse), such as to enable pulse coding. An energy reservoir circuit can be coupled to a laser diode driver circuit and to a power supply circuit and configured to store enough energy to fire the RD laser diode driver more than once. The energy reservoir circuit can act as an intermediate interface between the RD laser diode driver and the power supply circuit to better optimize the current requirements of each block.

Multi-phase laser driver techniques

The present disclosure provides numerous applications for the use of liquid crystal polarization gratings (LCPGs) to controllably steer light. When combined with an image sensor, light generated or reflected from different fields of view (FOV) can be steered, allowing an increase in the FOV or the resolution of the image. Further, the LCPG can stabilize the resulting image, counteracting any movement of the image sensor. The combination of LCPGs and liquid crystal waveguides (LCWGs) allows fine deflection control of light (from the LCWG) over a wild field of view (from the LCPG). Further applications of LCPGs include object tracking and the production of depth images using multiple imaging units and independently steered LCPGs. The LCPG may be used in controlling both the projection and reception of light.

Beam steering device using liquid crystal polarization gratings

Techniques to achieve higher power/shorter pulses with a laser diode. By initially applying a static reverse bias across the laser diode, the laser diode can turn on at a larger inductor current. When the laser diode is initially reverse biased, depletion charge and diffusion charge can be populated before the laser diode will lase. This causes the laser diode to initially turn on at a larger inductor current, which will reduce the rise time, thereby achieving higher power/shorter pulses.

Laser diode driver circuit techniques

Systems and methods for sensing angular motion using a microelectromechanical system (MEMS) gyroscope are described. These systems and methods may be useful for sensing angular motion in the presence of low-frequency noise, which may be noise below 1 KHz. In a system for sensing angular motion, low-frequency noise may give rise to duty cycle jitter, which may affect the demodulation of the sense signal and cause errors in angular motion estimates. The systems and methods described herein address this problem by relying on double-edge phase detection technique that involves sensing when the rising and falling edges of the resonator signal deviate from their expected values in the idealized 50% duty cycle scenario. To prevent the formation of ripples in the double-edge phase detection that may otherwise affect the demodulation of the sense signal, a switch may be used. The switch may be maintained in a non-conductive state when a ripple is received.

Systems and methods for sensing angular motion in the presence of low-frequency noise

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 fof 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.

Frequency mismatch detection method for mode matching in gyroscopes

A successive-approximation-register analog-to-digital converter (SAR ADC) typically includes circuitry for implementing bit trials that converts an analog input to a digital output bit by bit. The circuitry for bit trials are usually weighted (e.g., binary weighted), and these bit weights are not always ideal. Calibration algorithms can calibrate or correct for non-ideal bit weights and usually prefer these bit weights to be signal-independent so that the bit weights can be measured and calibrated/corrected easily. Embodiments disclosed herein relate to a unique circuit design of an SAR ADC, where each bit capacitor or pair of bit capacitors (in a differential design) has a corresponding dedicated on-chip reference capacitor. The speed of the resulting ADC is fast due to the on-chip reference capacitors (offering fast reference settling times), while errors associated with non-ideal bit weights of the SAR ADC are signal-independent (can be easily measured and corrected/calibrated).

SAR ADCs with dedicated reference capacitor for each bit capacitor

Circuits and methods for compensating microelectromechanical system (MEMS) gyroscopes for quality factor variations are described. Quality factor variations arise when mechanical losses are introduced in the gyroscope's resonator, for example due to thermoelastic damping or squeeze-film damping, which may hinder the gyroscope's ability to accurately sense angular velocity. Quality factor compensation may be performed by generating a compensation signal having a time decay rate that depends on the quality factor of resonator. In this way, artifacts that may otherwise arise in gyroscope's output are limited. Additionally, or alternatively, quality factor compensation may be performed by controlling the force with which the gyroscope's resonator is driven. This may be achieved, for example, by controlling the average value of the drive signal.

Quality factor compensation in microelectromechanical system (MEMS) gyroscopes

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.

Quality factor estimation for resonators

Systems and techniques are described for matching the resonance frequencies of multiple resonators. In some embodiments, a resonator generates an output signal reflecting the resonator's response to an input drive signal and an input noise signal. The output signal is then compared to the noise signal to derive a signal representative of the resonance frequency of the resonator. Comparing that signal to the output signal of a second resonator gives an indication of whether there is a difference between the resonance frequencies of the two resonators. If there is, one or both of the resonators may be adjusted. In this manner, the resonance frequencies of resonators may be matched during normal operation of the resonators.

Mode-matching of MEMS resonators

A successive approximation register analog-to-digital converter (SAR ADC) typically includes circuitry for implementing bit trials that converts an analog input to a digital output bit by bit. The circuitry for bit trials are usually weighted (e.g., binary weighted), and these bit weights are not always ideal. Calibration algorithms can calibrate or correct for non-ideal bit weights and usually prefer these bit weights to be signal independent so that the bit weights can be measured and calibrated/corrected easily. Embodiments disclosed herein relate to a unique circuit design of an SAR ADC, where each bit capacitor or pair of bit capacitors (in a differential design) has a corresponding dedicated on-chip reference capacitor. The speed of the resulting ADC is fast due to the on-chip reference capacitors (offering fast reference settling times), while errors associated with non-ideal bit weights of the SAR ADC are signal independent (can be easily measured and corrected/calibrated).

Systems for processing pixel signals generated by an image sensor to create improved images. More particularly, systems and methods are disclosed that adjust the gain on, inter alia, a pixel-by-pixel basis, to improve the dynamic range of the imaging system. The systems may include level detectors that measure the amplitude of a pixel signal and, based on that measurement, amplify that pixel signal by an amount that allows certain subsequent processing of the pixel signal to be more accurate. More accurately processed pixel signals can provide better overall images.

Adaptive gain adjustment in an imaging system

A gyroscope control circuit for a vibratory gyroscope system includes an open-loop RSP control circuit and a closed-loop CSP control circuit. The gyroscope control circuit optionally may include a Q compensation circuit to compensate for variations in gyroscope sensitivity due to variations in resonator signal path Q. The resonator signal path and the Coriolis signal path may have transduction factors that are proportional to each other such that sensitivity of the gyroscope varies directly with resonator signal path quality factor (Q).

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Bedford, MA, United States of America

Ronald Alan Kapusta