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Neural networks for neurocomputing circuits: A computational study of tolerance to noise and activation function non-uniformity when machine learning materials properties
(2025-12-01)
Thant, Ye min
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Nukunudompanich, Methawee
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Chueh, Chu Chen
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Ihara, Manabu
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Manzhos, Sergei
Dedicated analog neurocomputing circuits are promising for high-throughput, low power consumption applications of machine learning (ML) and for applications where implementing a digital computer is unwieldy (remote locations; small, mobile, and autonomous devices, extreme conditions, etc.). Neural networks (NN) implemented in such circuits, however, must contend with circuit noise and the non-uniform shapes of the neuron activation function (NAF) due to the dispersion of performance characteristics of circuit elements (such as transistors or diodes implementing the neurons). We present a computational study of the impact of circuit noise and NAF inhomogeneity in regression problems as a function of NN architecture and training regimes. We focus on one application that requires high-throughput ML: materials informatics, using as representative problem ML of formation energies vs. lowest-energy isomer of peri-condensed hydrocarbons, formation energies and band gaps of double perovskites, and zero point vibrational energies of molecules from QM9 dataset. We show that in these applications, NNs generally possess low noise tolerance with the model accuracy rapidly degrading with noise level. Single-hidden layer NNs, and NNs with larger-than-optimal sizes are somewhat more noise-tolerant. Models that show less overfitting (not necessarily the lowest test set error) are more noise-tolerant. Importantly, we demonstrate that the effect of activation function inhomogeneity can be palliated by retraining the NN using practically realized shapes of NAFs.
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A Simple and Compact Transimpedance Mode dc Bridge Readout
(2021-04-01)
Buakaew, Seangrawee
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Narksarp, Wipavan
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Wongtaychatham, Chariya
This paper presents a new circuit configuration of a transimpedance mode dc bridge based on an operational trans-resistance amplifier (OTRA) as an analog building block. The proposed circuit suits for small changing resistance detector. By taking the benefit of grounding property at the internal input port of the OTRA, a simple and compact dc bridge is obtained. The proposed circuit is composed of two sensing components together with a feedback resistor and only one operational trans-resistance amplifier. The circuit performances are verified by the PSPICE simulation using 0.35 m CMOS technology model parameters. The simulation results from circuit level agree well with the theoretical values.
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A transconductance-mode multifunction filter with high input and high output impedance nodes using voltage differencing current conveyors (Vdccs)
(2020-12-01)
Siripruchyanun, Montree
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Jaikla, Winai
The design of transconductance-mode multifunction biquad filter containing three input voltage nodes and single-output current node is proposed. Its circuit principle is emphasized on employing Voltage Differencing Current Conveyor (VDCC) to be an active building block. The proposed filter description uses three VDCCs co-working with two grounded capacitors and three grounded resistors. The synthesis of the proposed multifunction filter is based on avoidance of using multiple-output active elements to achieve commercially available integrated circuits for practical imple-mentation. Additionally, without multiple-output active element, it can alleviate current tracking error from the current mirrors used in output ports. It also decreases the amounts of the transistors inside the active elements. The proposed multifunction filter offers all 5 filter functions, which are non-inverting Low-Pass (LP), non-inverting High-Pass (HP), non-inverting Band-Pass (BP), non-inverting Band-Reject (BR) and also non-inverting All-Pass (AP) functions from same circuit topology under different circuit condition for input signals. Furthermore, the natural frequency for all filtering responses is independently achieved from the bandwidth or the quality factor of the proposed fil-ter. For cascade-able connectivity, the output current port indeed provides a high impedance. In addition, the magnitude of the output current for all filtering functions can be resistively adjusted. The consideration for non-ideal case of the presented multifunction filter is also analyzed. The simulation and experimental results of the presented transconductance multifunction biquad filter based on VDCC practically implemented by the commercially available ICs, LM13700 and AD844 can validate the theoretical anticipation.
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Extremely low-voltage low-power differential difference current conveyor using multiple-input bulk-driven technique
(2020-08-01)
Kumngern, Montree
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Khateb, Fabian
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Kulej, Tomasz
In this paper, a new differential difference current conveyor (DDCC) with ultra-low voltage and low-power capability is presented. The DDCC is designed by using a non-tailed differential pair with multiple-input bulk-driven MOS transistor technique to obtain a rail-to-rail input common-mode swing and extremely low supply voltage. The MOS transistors biased in the sub-threshold region have been used to achieve extremely low power consumption. The performance of the proposed DDCC is evaluated by simulation results using SPICE program and MOS transistors parameters provided by a standard n-well 0.18 µm CMOS process from TSMC. A rail-to-rail input common-mode range was shown and a high accuracy was expressed. The bandwidth was 2.2 kHz and the total harmonic distortion was 1% for an input signal with amplitude of 240 mV<inf>p-p</inf>, obtained at supply voltage of 0.3 V and power dissipation of 28.6 nW. The proposed DDCC has been used to realize a sixth-order low-pass filter for application to electrocardiogram (ECG) applications.
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0.5 V fully differential universal filter based on multiple input OTAs
(2020-01-01)
Jaikla, Winai
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Khateb, Fabian
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Kumngern, Montree
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Kulej, Tomasz
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Ranjan, Rajeev Kumar
The design of a low-power, low-voltage, fully-differential universal biquad filter is presented in this work, which is constructed from four multiple-input gate-driven operational transconductance amplifiers (MI-OTAs) along with one passive resistor and two passive capacitors. The scheme of presented biquad filter has three high-input impedance voltage nodes and single output voltage node. Five unity gain filtering functions, all-pass (AP), low-pass (LP), band-pass (BP), high-pass (HP) and band-stop (BS) responses, are obtained. The selection of output filtering responses is obtained without the need of component matching condition, inverting or double input voltage. With this feature, it can be easily controlled with digital programming. The quality factor (Q) and angular frequency (ω<inf>0</inf>) are electronically and independently tuned. Moreover, the adjustment of ω<inf>0</inf> and Q can be done without affecting the voltage gain. A workability of the design is confirmed via Cadence software and the Spectre simulator based on the 180 nm TSMC CMOS technology parameters. The proposed fully differential filter operates with 0.5 V supply voltage. The results verify that the proposed filter dissipates the total power of 53.3 nW. Additionally, the dynamic range (DR) of band-pass filtering function is 63 dB for 2% third intermodulation distortion (IMD). Also, the simulated RMS value of the band-pass filtering noise is 45 µV.
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0.4 V fully differential current conveyor using multiple-input bulk-driven MOST technique
(2019-08-01)
Kumngern, Montree
This paper presents a new ultra-low voltage ultra-low power fully differential current conveyor (FDCCII) which is suitable for extremely low-voltage low-power analog signal circuit applications. Thanks to multiple-input bulk-driven MOS transistor technique, the proposed structure employs two differential pairs which offer low complexity and low power consumption. The bulk-driven MOS technique based circuit also provides rail-to-rail input common-mode range of proposed circuit. To prove the workability of the proposed FDCCII, the circuit has been used to realize summing/subtracting amplifier as design examples. The performances of the proposed FDCCII and design examples are demonstrated through PSPICE simulations using a 0.18 μm TSMC n-well CMOS process with 0.4 V supply voltage.
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Bulk-driven fully balanced second-generation current conveyor in 0.18 µm CMOS
(2019-05-01)
Kumngern, Montree
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Khateb, Fabian
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Kulej, Tomasz
This paper presents an ultra-low-voltage and low-power fully balanced second-generation current conveyor (FBCCII) which is suitable for applications in ultra-low-voltage and low-power analog circuits. To confirm the attractive features of proposed FBCCII, the analog circuits such as fully digital programmable voltage gain amplifier, fully all-pass sections, fully band-pass filter and fully universal filter using the proposed FBCCII as active element have been proposed. The performances of the proposed FBCCII and its applications can be depicted through simulation results using SPICE simulations and 0.18 µm n-well CMOS process from TSMC with a 0.5 V supply.
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Five-inputs single-output voltage mode universal filter with high input and low output impedance using VDDDAs
(2017-01-01)
Sangyaem, Surasak
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Siripongdee, Surapong
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Jaikla, Winai
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Khateb, Fabian
The design of analog filter using active building block has been gained significant attention and has become an interesting research topic. A five-inputs single −output voltage-mode universal biquadratic filter using active building block, namely voltage differencing differential difference amplifier (VDDDA) is presented in this paper. The proposed filter consists of two VDDDAs and two grounded capacitors. The presented circuit has high impedance for all input voltage nodes and low impedance for output voltage node which is ideal for cascade in voltage-mode circuit without the use of buffer circuits. It can provide five output voltage functions which are band-pass (BP), low-pass (LP), band-reject (BR), high-pass (HP) and all-pass (AP) responses. For high-pass and band-pass functions, the inverting and non-inverting response can be achieved. The matching condition, the inverting and double gain amplifier are not required which is easy to select the output response by digital method. The natural frequency and quality factor can be electronically tuned that is attractive for microcomputer or microcontroller controllability. To verify the validity of proposed filter, the PSPICE simulation and experimental results using VDDDA constructed from commercially available IC are included. The measured results agree well with theoretical expect.
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Electronically controlled high input and low output impedance voltage mode multifunction filter with grounded capacitors
(2014-12-01)
Ninsraku, Wilas
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Biolek, Dalibor
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Jaikla, Winai
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Siripongdee, Surapong
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Suwanjan, Peerawut
In this study, a three-input single-output voltage-mode biquadratic filter employing voltage differencing differential input buffered amplifier (VD-DIBA) is presented. The proposed filter uses two VD-DIBAs and two grounded capacitors without any external resistors, which is well suited for integrated circuit implementation. The circuit provides five standard transfer functions, namely, low pass, high pass, band pass, notch and all pass filters with electronic control of quality factor and pole frequency. Each transfer function can be selected by suitably selecting input signals via digital method. The filter does not require inverting of the input voltage signal. Moreover, the circuit possesses high input and low output impedances and thus it enables simple voltage-mode cascading. The PSPICE simulation and also experimental results are included, verifying the workability of the proposed filter. The given results agree well with the theoretical anticipation.
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Electronically tunable current-mode biquad filter employing CCCDTAs and grounded capacitors with low input and high output impedance
(2013-12-01)
Jaikla, Winai
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Khateb, Fabian
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Siripongdee, Surapong
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Supavarasuwat, Piya
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Suwanjan, Peerawut
In this study, a single-input multiple-outputs current-mode analog biquadratic filter, based on current controlled current differencing transconductance amplifier (CCCDTA) is presented. The proposed filter uses two CCCDTAs and two grounded capacitors without any external resistors, which is well suited for integrated circuit implementation. The filter simultaneously gives 3 standard transfer functions, namely, lowpass, highpass and bandpass filters with independent control of quality factor and pole frequency by electronic method. By summing of I<inf>HP</inf> and L<inf>LP</inf>, the notch filter can be also achieved. Moreover, the circuit has low input and high output impedance which would be an ideal choice for cascading in current-mode circuit. The PSPICE simulation results are included verifying the workability of the proposed filter. The given results agree well with the theoretical anticipation. © 2013 Elsevier GmbH.

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