scholarly journals An Auto-Tuning Continuous-Time Bandpass Sigma-Delta Modulator with Signal Observation for MEMS Gyroscope Readout Systems

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 1973
Author(s):  
Chunge Ju ◽  
Xiang Li ◽  
Junjun Zou ◽  
Qi Wei ◽  
Bin Zhou ◽  
...  

This paper presents the design and implementation of an auto-tuning continuous-time bandpass sigma-delta (ΣΔ) modulator for micro-electromechchanical systems (MEMS) gyroscope readout systems. Its notch frequency can well match the input signal frequency by adding a signal observation to the traditional ΣΔ modulator. The filter of the observation adopts the same architecture as that of the traditional ΣΔ modulator, allowing the two filters to have the same response to input signal change, which is converted into a control voltage on metal-oxide semiconductor (MOS) resistance in the filters. The automatic tuning not only works to solve the mismatch problem caused by process error and temperature variation, but can also be applied to the interface circuit of gyroscopes with different resonant frequencies. The circuit is implemented in a 0.18-μm complementary metal-oxide semiconductor (CMOS) process with a core area of 2.4 mm2. The improved modulator achieves a dynamic range of 106 dB, a noise floor below 120 dB and a maximum signal-to-noise and distortion ratio (SNDR) of 86.4 dB. The tuning capability of the chip is relatively stable under input signals from 6 to 15 kHz at temperatures ranging from −45 to 60 °C.

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1683
Author(s):  
Winai Jaikla ◽  
Fabian Khateb ◽  
Tomasz Kulej ◽  
Koson Pitaksuttayaprot

This paper proposes the simulated and experimental results of a universal filter using the voltage differencing differential difference amplifier (VDDDA). Unlike the previous complementary metal oxide semiconductor (CMOS) structures of VDDDA that is present in the literature, the present one is compact and simple, owing to the employment of the multiple-input metal oxide semiconductor (MOS) transistor technique. The presented filter employs two VDDDAs, one resistor and two grounded capacitors, and it offers low-pass: LP, band-pass: BP, band-reject: BR, high-pass: HP and all-pass: AP responses with a unity passband voltage gain. The proposed universal voltage mode filter has high input impedances and low output impedance. The natural frequency and bandwidth are orthogonally controlled by using separated transconductance without affecting the passband voltage gain. For a BP filter, the root mean square (RMS) of the equivalent output noise is 46 µV, and the third intermodulation distortion (IMD3) is −49.5 dB for an input signal with a peak-to peak of 600 mV, which results in a dynamic range (DR) of 73.2 dB. The filter was designed and simulated in the Cadence environment using a 0.18-µm CMOS process from Taiwan semiconductor manufacturing company (TSMC). In addition, the experimental results were obtained by using the available commercial components LM13700 and AD830. The simulation results are in agreement with the experimental one that confirmed the advantages of the filter.


Sensors ◽  
2019 ◽  
Vol 19 (19) ◽  
pp. 4149
Author(s):  
Xiang Li ◽  
Rui Li ◽  
Chunge Ju ◽  
Bo Hou ◽  
Qi Wei ◽  
...  

Micromachined gyroscopes require high voltage (HV) for actuation and detection to improve its precision, but the deviation of the HV caused by temperature fluctuations will degrade the sensor’s performance. In this paper, a high-voltage temperature-insensitive charge pump is proposed. Without adopting BCD (bipolar-CMOS-DMOS) technology, the output voltage can be boosted over the breakdown voltage of n-well/substrate diode using triple-well NMOS (n-type metal-oxide-semiconductor) transistors. By controlling the pumping clock’s amplitude continuously, closed-loop regulation is realized to reduce the output voltage’s sensitivity to temperature changes. Besides, the output level is programmable linearly in a large range by changing the reference voltage. The whole circuit has been fabricated in a 0.18- μ m standard CMOS (complementary metal-oxide-semiconductor) process with a total area of 2.53 mm 2 . Measurements indicate that its output voltage has a linear adjustable range from around 13 V to 16.95 V, and temperature tests show that the maximum variations of the output voltage at − 40 ∼ 80 ∘ C are less than 1.1%.


Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4731
Author(s):  
Wei-Ren Chen ◽  
Yao-Chuan Tsai ◽  
Po-Jen Shih ◽  
Cheng-Chih Hsu ◽  
Ching-Liang Dai

The fabrication and characterization of a magnetic micro sensor (MMS) with two magnetic field effect transistors (MAGFETs) based on the commercial complementary metal oxide semiconductor (CMOS) process are investigated. The magnetic micro sensor is a three-axis sensing type. The structure of the magnetic microsensor is composed of an x/y-MAGFET and a z-MAGFET. The x/y-MAGFET is employed to sense the magnetic field (MF) in the x- and y-axis, and the z-MAGFET is used to detect the MF in the z-axis. To increase the sensitivity of the magnetic microsensor, gates are introduced into the two MAGFETs. The sensing current of the MAGFET enhances when a bias voltage is applied to the gates. The finite element method software Sentaurus TCAD was used to analyze the MMS’s performance. Experiments show that the MMS has a sensitivity of 182 mV/T in the x-axis MF and a sensitivity of 180 mV/T in the y-axis MF. The sensitivity of the MMS is 27.8 mV/T in the z-axis MF.


Author(s):  
Jing-Hung Chiou ◽  
Ching-Liang Dai ◽  
Jen-Yi Chen ◽  
Michael S.-C. Lu

This work describes a new post-CMOS (Complementary Metal Oxide Semiconductor) bulk micromachining process for fabrication of various microstructures. The important feature of the post-CMOS process is the use of wet etching without an addition mask, to form various microstructures and deep cavities in the silicon substrate. The post-CMOS process starts with wet etching to remove sacrificial layers, which are stacked layers of metals and vias, to expose the silicon substrate. Then, KOH or TMAH solution is employed to etch the silicon substrate to form various deep cavities and suspended structures. Many suspended structures, which include beams, bridges and plates, are fabricated using the standard 0.35-μm SPFM (Single Polysilicon Four Metal) CMOS process and the post-CMOS process. Experimental results reveals that a plate with an area of 200×200 μm2, a bridge with a length of 300μm, and various beams with lengths from 100-μm to 400-μm suspended on a deep cavity were fabricated successfully.


1989 ◽  
Vol 67 (4) ◽  
pp. 184-189 ◽  
Author(s):  
M. Parameswaran ◽  
Lj. Ristic ◽  
A. C. Dhaded ◽  
H. P. Baltes ◽  
W. Allegretto ◽  
...  

Complementary metal oxide semiconductor (CMOS) technology is one of the leading fabrication technologies of the semiconductor integrated-circuit industry. We have discovered features inherent in the standard CMOS fabrication process that lend themselves to the manufacturing of micromechanical structures for sensor applications. In this paper we present an unconventional layout design methodology that allows us to exploit the standard CMOS process for producing microbridges. Two types of microbridges, bare polysilicon microbridges and sandwiched oxide microbridges, have been manufactured by first implementing a special layout design in an industrial digital CMOS process, followed by a postprocessing etching step.


2021 ◽  
Vol 11 (10) ◽  
pp. 4650
Author(s):  
Jie Miao ◽  
Houpeng Chen ◽  
Yu Lei ◽  
Yi Lv ◽  
Weili Liu ◽  
...  

The thermoelectric generator (TEG) stands out among many energy harvesters due to its simple structure, small size, rich thermal energy, and the absence of pollution and noise. However, previous studies have rarely probed into the influence of TEG internal resistances on extracting maximum power from TEGs, and the tracking of efficiency is limited. By analyzing the relationship between the tracking efficiency and the TEG internal resistances, a time exponential rate perturbation and observation (P&O) technology is proposed to achieve maximum power point tracking (MPPT) for a wide resistance range of the TEG. Using the time exponential rate P&O, the MPPT circuit observed the power change by comparing the positive-channel metal-oxide semiconductor (PMOS) on-time and perturbs the power by adjusting the negative-channel metal-oxide semiconductor (NMOS) on-time exponentially. The MPPT circuit was implemented in a 110 nm complementary metal-oxide semiconductor (CMOS) process. The tracking efficiency maintained a high level from 98.9 to 99.5%. The applicable range of the TEG resistance was from 1 to 12 Ω, which reflects an enhancement of at least 2.2 times.


Electronics ◽  
2021 ◽  
Vol 10 (17) ◽  
pp. 2114
Author(s):  
Giorgio Maiellaro ◽  
Giovanni Caruso ◽  
Salvatore Scaccianoce ◽  
Mauro Giacomini ◽  
Angelo Scuderi

This paper presents a 40 GHz voltage-controlled oscillator (VCO) and frequency divider chain fabricated in STMicroelectronics 28 nm ultrathin body and box (UTBB) fully depleted silicon-on-insulator (FD-SOI) complementary metal-oxide–semiconductor (CMOS) process with eight metal layers back-end-of-line (BEOL) option. VCOs architecture is based on an LC-tank with p-type metal-oxide–semiconductor (PMOS) cross-coupled transistors. VCOs exhibit a tuning range (TR) of 3.5 GHz by exploiting two continuous frequency tuning bands selectable via a single control bit. The measured phase noise (PN) at 38 GHz carrier frequency is −94.3 and −118 dBc/Hz at 1 and 10 MHz frequency offset, respectively. The high-frequency dividers, from 40 to 5 GHz, are made using three static CMOS current-mode logic (CML) Master-Slave D-type Flip-Flop stages. The whole divider factor is 2048. A CMOS toggle flip-flop architecture working at 5 GHz was adopted for low frequency dividers. The power dissipation of the VCO core and frequency divider chain are 18 and 27.8 mW from 1.8 and 1 V supply voltages, respectively. Circuit functionality and performance were proved at three junction temperatures (i.e., −40, 25, and 125 °C) using a thermal chamber.


Micromachines ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1303
Author(s):  
Hoontaek Lee ◽  
Junsoo Kim ◽  
Kumjae Shin ◽  
Wonkyu Moon

We report recent improvements of the tip-on-gate of field-effect-transistor (ToGoFET) probe used for capacitive measurement. Probe structure, fabrication, and signal processing were modified. The inbuilt metal-oxide-semiconductor field-effect-transistor (MOSFET) was redesigned to ensure reliable probe operation. Fabrication was based on the standard complementary metal-oxide-semiconductor (CMOS) process, and trench formation and the channel definition were modified. Demodulation of the amplitude-modulated drain current was varied, enhancing the signal-to-noise ratio. The - characteristics of the inbuilt MOSFET reflect the design and fabrication modifications, and measurement of a buried electrode revealed improved ToGoFET imaging performance. The minimum measurable value was enhanced 20-fold.


2021 ◽  
Vol 5 (2) ◽  
pp. 46
Author(s):  
Evisa Memlikai ◽  
Stavroula Kapoulea ◽  
Costas Psychalinos ◽  
Jerzy Baranowski ◽  
Waldemar Bauer ◽  
...  

An alternative procedure for the implementation of fractional-order compensators is presented in this work. The employment of a curve-fitting-based approximation technique for the approximation of the compensator transfer function offers improved accuracy compared to the Oustaloup and Padé methods. As a design example, a lead compensator intended for usage in car suspension systems is realized. The open-loop and closed-loop behavior of the system is evaluated by post-layout simulation results obtained using the Cadence IC design suite and the Metal Oxide Semiconductor (MOS) transistor models provided by the Austria Mikro Systeme 0.35 m Complementary Metal Oxide Semiconductor (CMOS) process. The derived results verify the efficient performance of the introduced implementation.


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