SNDR Limits of Oscillator-Based Sensor Readout Circuits

Cardes, Fernando; Quintero, Andrés; Gutierrez, Eric; Buffa, Cesare; Wiesbauer, A.; Hernández, Luis

doi:10.3390/s18020445

Cited by 29 publications

(34 citation statements)

References 36 publications

(40 reference statements)

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“…The benefits of the Oscillator-based approach have been widely examined and demonstrated across the literature [15], [16], [18], [19], providing scalability, linearity, robust measurement against process variations and programmable sensor response. In this paper, the benefits are expanded by proposing a compact 2-stage Sawtooth Oscillator capable of sensing and encoding both ion concentration and solution temperature into a single PWM output signal, achieving dual-sensing thermochemical measurement.…”

Section: Pixel Architecturementioning

confidence: 99%

A Dual-Sensing Thermo-Chemical ISFET Array for DNA-Based Diagnostics

Cacho-Soblechero

Malpartida-Cardenas

Cicatiello

et al. 2020

IEEE Trans. Biomed. Circuits Syst.

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This paper presents a 32x32 ISFET array with inpixel dual-sensing and programmability targeted for on-chip DNA amplification detection. The pixel architecture provides thermal and chemical sensing by encoding temperature and ion activity in a single output PWM, modulating its frequency and its duty cycle respectively. Each pixel is composed of an ISFETbased differential linear OTA and a 2-stage sawtooth oscillator. The operating point and characteristic response of the pixel can be programmed, enabling trapped charge compensation and enhancing the versatility and adaptability of the architecture. Fabricated in 0.18µm standard CMOS process, the system demonstrates a quadratic thermal response and a highly linear pH sensitivity, with a trapped charge compensation scheme able to calibrate 99.5% of the pixels in the target range, achieving a homogeneous response across the array. Furthermore, the sensing scheme is robust against process variations and can operate under various supply conditions. Finally, the architecture suitability for on-chip DNA amplification detection is proven by performing Loop-mediated Isothermal Amplification (LAMP) of phage lambda DNA, obtaining a time-to-positive of 7.71 minutes with results comparable to commercial qPCR instruments. This architecture represents the first in-pixel dual thermo-chemical sensing in ISFET arrays for Lab-on-a-Chip diagnostics.

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Section: Pixel Architecturementioning

confidence: 99%

A Dual-Sensing Thermo-Chemical ISFET Array for DNA-Based Diagnostics

Cacho-Soblechero

Malpartida-Cardenas

Cicatiello

et al. 2020

IEEE Trans. Biomed. Circuits Syst.

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“…Firstly, it is known that phase noise is the main limiting factor for high-resolution low-bandwidth applications, such as audio or biomedical sensing. To overcome this issue noise simulations must be made first to calculate the input-referred phase noise [22] and compare it with the required resolution. Then, parameters like the number of phases, the power consumption and the devices' sizes must be adjusted to accomplish with that noise requirement.…”

Section: Circuit Impairmentsmentioning

confidence: 99%

Time-Encoding-Based Ultra-Low Power Features Extraction Circuit for Speech Recognition Tasks

et al. 2020

Self Cite

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Current trends towards on-edge computing on smart portable devices requires ultra-low power circuits to be able to make feature extraction and classification tasks of patterns. This manuscript proposes a novel approach for feature extraction operations in speech recognition/voice activity detection tasks suitable for portable devices. Whereas conventional approaches are based on either completely analog or digital structures, we propose a “hybrid” approach by means of voltage-controlled-oscillators. Our proposal makes use of a bank a band-pass filters implemented with ring-oscillators to extract the features (energy within different frequency bands) of input audio signals and digitize them. Afterwards, these data will input a digital classification stage such as a neural network. Ring-oscillators are structures with a digital nature, which makes them highly scalable with the possibility of designing them with minimum length devices. Additionally, due to their inherent phase integration, low-frequency band-pass filters can be implemented without large capacitors. Consequently, we strongly benefit from power consumption and area savings. Finally, our proposal may incorporate the analog-to-digital converter into the structure of the own features extractor circuit to make the full conversion of the raw data when triggered. This supposes a unique advantage with respect to other approaches. The architecture is described and proposed at system-level, along with behavioral simulations made to check whether the performance is the expected one or not. Then the structure is designed with a 65-nm CMOS process to estimate the power consumption and area on a silicon implementation. The results show that our solution is very promising in terms of occupied area with a competitive power consumption in comparison to other state-of-the-art solutions.

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“…This sort of oscillator is called a voltage controlled oscillator (VCO) or current controlled oscillator (CCO). Many voltage controlled oscillators are found in sensor applications, for example, in impedance spectroscopy [1], microelectromechanical systems (MEMS) sensor [4], IoT sensors [5,6], motion detection sensors [7], sensor readout circuit [8], wireless sensor network [9][10][11], basal-body-temperature detection sensor [12], image sensor [13], intelligent human sensing system [14], etc. These voltage controlled oscillators are designed and implemented in CMOS chips, which provides many advantages, for example, low power consumption, compact size, low voltage operation, high speed, etc.…”

Section: Introductionmentioning

confidence: 99%

Current/Voltage Controlled Quadrature Sinusoidal Oscillators for Phase Sensitive Detection Using Commercially Available IC

Jaikla

Adhan

Suwanjan

et al. 2020

Sensors

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This paper presents the quadrature sinusoidal oscillators for a phase sensitive detection (PSD) system. The proposed oscillators are design by using the commercially available ICs (LT1228). The core oscillator consists of three LT1228s: two grounded capacitors and one resistor. By adding four resistors without the requirement of additional active devices, the amplitudes of two quadrature waveforms become adjustable. The quadrature output nodes are of low impedance, which can be connected to the impedance sensor or other circuits in a phase sensitive detection system without the need of buffer devices. The amplitudes of the quadrature waveform are equal during the frequency of oscillation (FO) tuning. The frequency of oscillation is electronically and linearly controlled by bias current or voltage without affecting the condition of oscillation (CO). Furthermore, the condition of oscillation is electronically controlled without affecting the frequency of oscillation. The performances of the proposed oscillators are experimentally tested with ±5 voltage power supplies. The frequency of the proposed sinusoidal oscillator can be tuned from 8.21 kHz to 1117.51 kHz. The relative frequency error is lower than 3.12% and the relative phase error is lower than 2.96%. The total harmonic distortion is lower than −38 dB (1.259%). The voltage gain of the quadrature waveforms can be tuned from 1.97 to 15.92. The measurement results demonstrate that the proposed oscillators work in a wide frequency range and it is a suitable choice for an instrument-off-the-shelf device

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SNDR Limits of Oscillator-Based Sensor Readout Circuits

Cited by 29 publications

References 36 publications

A Dual-Sensing Thermo-Chemical ISFET Array for DNA-Based Diagnostics

A Dual-Sensing Thermo-Chemical ISFET Array for DNA-Based Diagnostics

Time-Encoding-Based Ultra-Low Power Features Extraction Circuit for Speech Recognition Tasks

Current/Voltage Controlled Quadrature Sinusoidal Oscillators for Phase Sensitive Detection Using Commercially Available IC

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