Cuong Do

An Efficient SSHI Interface With Increased Input Range for Piezoelectric Energy Harvesting Under Variable Conditions

Piezoelectric vibration energy harvesters have been widely researched and are increasingly employed for powering wireless sensor nodes. The synchronized switch harvesting on inductor (SSHI) circuit is one of the most efficient interfaces for piezoelectric vibration energy harvesters. However, the traditional incarnation of this circuit suffers from a significant startup issue that limits operation in low and variable amplitude vibration environments. This paper addresses this start-up issue for the SSHI rectifier by proposing a new architecture with SSHI startup circuitry. The startup circuitry monitors if the SSHI circuit is operating correctly and re-starts the SSHI interface if required. The proposed circuit is comprehensively analyzed and experimentally validated through tests conducted by integrating a commercial piezoelectric vibration energy harvester with the new interface circuit designed in a 0.35-μm HV CMOS process. Compared to conventional SSHI rectifiers, the proposed circuit significantly decreases the required minimum input excitation amplitude before energy can be harvested, making it possible to extract energy over an increased excitation range.

Observation of three-mode parametric instability in a micromechanical resonator

We present systematic experimental observations of three-mode auto-parametric instability in a micromechanical resonator analogous to previous experimental observations of this effect in optical parametric resonators. The three-mode instability is triggered when a driven mode at frequency ωd couples to two lower frequency modes (frequencies ω1 and ω2) such that ωd = ω1 + ω2. Similar to the 2 mode instability, the phenomenon is seen to be threshold dependent and sensitive to driving conditions and system parameters. In support of the experimental observations, a dynamical model has also been specified.

Vacuum packaged low-power resonant MEMS strain gauge

This paper describes a technical approach toward the realization of a low-power temperature-compensated micromachined resonant strain sensor. The sensor design is based on two identical and orthogonally-oriented resonators where the differential frequency is utilized to provide an output proportional to the applied strain with temperature compensation achieved to first order. Interface circuits comprising of two front-end oscillators, a mixer, and low-pass filter are designed and fabricated in a standard 0.35-

A Hybrid Vibration Powered Microelectromechanical Strain Gauge

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Low power MEMS oscillators for sensor applications

CMOS process. The characterized devices demonstrate a scale factor of 2.8 Hz/

Frequency transitions in phononic four-wave mixing

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Phononic frequency comb via three-mode parametric three-wave mixing

over a strain range of 1000

Excitation of multiple 2-mode parametric resonances by a single driven mode

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Excitation of coupled phononic frequency combs via two-mode parametric three-wave mixing

with excellent linearity over the measurement range. The compensated frequency drift due to temperature is reduced to 4% of the uncompensated value through this scheme. The total continuous power consumption of the strain sensor is 3

Phononic frequency comb via three-mode parametric resonance

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