A Nanopower Bandpass Filter for Detection of an Acoustic Signal in a Wearable Breathing Detector

Corbishley, P.; Rodriguez‐Villegas, Esther

doi:10.1109/tbcas.2007.913129

Cited by 92 publications

(42 citation statements)

References 21 publications

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“…In this case, some data processing tasks have to be located directly at the sensor level. This concept requires the development of energy efficient and low chip area signal processing blocks (Corbishley & Rodriguez-Villegas, 2007). The proposed low power SOM fits this concept, offering even four orders of magnitude better data rate to energy consumption ratio than a SOM implemented on a typical PC.…”

Section: Introductionmentioning

confidence: 99%

A programmable triangular neighborhood function for a Kohonen self-organizing map implemented on chip

et al. 2012

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a b s t r a c tAn efficient transistor level implementation of a flexible, programmable Triangular Function (TF) that can be used as a Triangular Neighborhood Function (TNF) in ultra-low power, self-organizing maps (SOMs) realized as Application-Specific Integrated Circuit (ASIC) is presented. The proposed TNF block is a component of a larger neighborhood mechanism, whose role is to determine the distance between the winning neuron and all neighboring neurons. Detailed simulations carried out for the software model of such network show that the TNF forms a good approximation of the Gaussian Neighborhood Function (GNF), while being implemented in a much easier way in hardware. The overall mechanism is very fast.In the CMOS 0.18 µm technology, distances to all neighboring neurons are determined in parallel, within the time not exceeding 11 ns, for an example neighborhood range, R, of 15. The TNF blocks in particular neurons require another 6 ns to calculate the output values directly used in the adaptation process. This is also performed in parallel in all neurons. As a result, after determining the winning neuron, the entire map is ready for the adaptation after the time not exceeding 17 ns, even for large numbers of neurons. This feature allows for the realization of ultra low power SOMs, which are hundred times faster than similar SOMs realized on PC. The signal resolution at the output of the TNF block has a dominant impact on the overall energy consumption as well as the silicon area. Detailed system level simulations of the SOM show that even for low resolutions of 3 to 6 bits, the learning abilities of the SOM are not affected. The circuit performance has been verified by means of transistor level Hspice simulations carried out for different transistor models and different values of supply voltage and the environment temperature -a typical procedure completed in case of commercial chips that makes the obtained results reliable.

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Section: Introductionmentioning

confidence: 99%

A programmable triangular neighborhood function for a Kohonen self-organizing map implemented on chip

et al. 2012

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“…3(a), consists of two differential pairs connected in a doublet arrangement with input transistor width ratio 5:1. This ratio is chosen to maximise the differential input range for a Total Harmonic Distortion (THD) of 1% [16]. For nominal operation the bias current is set at 200 pA.…”

Section: Methodsmentioning

confidence: 99%

A Subhertz Nanopower Low-Pass Filter

Rodriguez‐Villegas

Casson

Corbishley

2011

IEEE Trans. Circuits Syst. II

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Abstract-This brief presents a first order low pass filter topology capable of providing cut-off frequencies down to 2 mHz with a power consumption of 5 nW. The circuit is intended for signal conditioning applications, particularly for use with very low frequency physiological signals in low power portable medical equipment. To achieve the low frequency cut-off the filter is based around the use of a clocked transconductor which provides a low transconductance while using a relatively high bias current level. The circuit is implemented in a 0.35 µm technology with a 1 V supply and has a measured 32 µV RMS of noise and 64 dB dynamic range. In terms of power consumption and cut-off frequency the reported filter outperforms previous filters from the literature.

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“…It can be seen that the power consumption of this filter-bank compares favorably with the SoTA for a similar dynamic range inspite of the implementation in a sub-100nm technology. This affords a greater than 1.5X improvement in the Figure-of-Merit (FoM) proposed in [6]. Also, this design, unlike the SoTA does not need non-standard CMOS transistors such as floating gate devices or BiCMOS technology.…”

Section: Fc (Hz)mentioning

confidence: 98%

A switched-capacitor degenerated, scalable gm-C filter-bank for acoustic front-ends

Badami

Pamula

Verhelst

2016

2016 IEEE International Symposium on Circuits and Systems (ISCAS)

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Abstract-Filter-banks based on a gm−C topology are popular in acoustic sensor systems targeting spectral analysis. Their benefits lie in a very low power consumption and center-frequency scalability through gm-tuning to cover the audio frequency range. However the linear signal swing at the output of the filter is limited due to the inherent non-linearity of the input transistors in a differential pair. This work assesses the impact of noise and center-frequency specifications on the power consumption of 2 OTA based gm − C bandpass filters, both from a theoretical and practical point of view. Next, we introduce a novel scalable switched-capacitor based degeneration technique that enhances the linear signal swing at the filter output. Simulation results in 90nm CMOS demonstrate a power consumption of only 44nW for a bandpass filter with Q-factor of 1 with 63 dB dynamic range (< 2% THD) and a center-frequency of 100Hz. This scales to only 1.4μW for a center-frequency at 3.2kHz. These power consumption numbers compare favorably with the state-of-theart and enhance the Figure of Merit by more than 1.5X for a similar dynamic range.

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A Nanopower Bandpass Filter for Detection of an Acoustic Signal in a Wearable Breathing Detector

Cited by 92 publications

References 21 publications

A programmable triangular neighborhood function for a Kohonen self-organizing map implemented on chip

A programmable triangular neighborhood function for a Kohonen self-organizing map implemented on chip

A Subhertz Nanopower Low-Pass Filter

A switched-capacitor degenerated, scalable gm-C filter-bank for acoustic front-ends

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