High performance, integrated 1T1R oxide-based oscillator: Stack engineering for low-power operation in neural network applications

Sharma, Abhishek; Jackson, Thomas C.; Schulaker, M.; Kuo, C.; Augustine, Charles; Bain, James A.; Wong, H.-S. Philip; Mitra, Subhasish; Pileggi, Lawrence T.; Weldon, Jeffrey A.

doi:10.1109/vlsit.2015.7223672

Cited by 10 publications

(15 citation statements)

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“…As the charging is through the RRAM and the discharging is through the MIT device at RON, the RC delay of the charging is larger than that of the discharging, which makes the voltage oscillation a triangular waveform. The oscillation of the MIT device in such circuit configurations has been widely observed in various experiments [8,[17][18][19][20], showing its feasibility as the oscillation neuron. By solving the Kirchhoff's Law of Fig.…”

Section: Metal-insulator-transition Phenomenonmentioning

confidence: 89%

Compact oscillation neuron exploiting metal-insulator-transition for neuromorphic computing

Chen

Seo

Cao

et al. 2016

Proceedings of the 35th International Conference on Computer-Aided Design

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The phenomenon of metal-insulator-transition (MIT) in strongly correlated oxides, such as NbO2, have shown the oscillation behavior in recent experiments. In this work, the MIT based two-terminal device is proposed as a compact oscillation neuron for the parallel read operation from the resistive synaptic array. The weighted sum is represented by the frequency of the oscillation neuron. Compared to the complex CMOS integrateand-fire neuron with tens of transistors, the oscillation neuron achieves significant area reduction, thereby alleviating the column pitch matching problem of the peripheral circuitry in resistive memories. Firstly, the impact of MIT device characteristics on the weighted sum accuracy is investigated when the oscillation neuron is connected to a single resistive synaptic device. Secondly, the array-level performance is explored when the oscillation neurons are connected to the resistive synaptic array. To address the interference of oscillation between columns in simple cross-point arrays, a 2-transistor-1-resistor (2T1R) array architecture is proposed at negligible increase in array area. Finally, the circuitlevel benchmark of the proposed oscillation neuron with the CMOS neuron is performed. At single neuron node level, oscillation neuron shows >12.5X reduction of area. At 128×128 array level, oscillation neuron shows a reduction of ~4% total area, >30% latency, ~5X energy and ~40X leakage power, demonstrating its advantage of being integrated into the resistive synaptic array for neuro-inspired computing.

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Section: Metal-insulator-transition Phenomenonmentioning

confidence: 89%

Compact oscillation neuron exploiting metal-insulator-transition for neuromorphic computing

Chen

Seo

Cao

et al. 2016

Proceedings of the 35th International Conference on Computer-Aided Design

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“…This is especially important in dense array-type implementations. Sharma et al [22] shed significant light on the methods of reducing power of this class of oscillators down to <100 μW. Being relaxation oscillators, the peak power is dissipated in these oscillators during the capacitive discharging event that leads to a current spike.…”

Section: Discussionmentioning

confidence: 99%

“…Prior to failure (by forming), the oscillators could undergo a change in frequency, especially for the high power modes of operation, as in [11]. Our recent works show that the presence of different load ballasts [6], [22] or drive [3] elements can be used to provide a degenerative feedback mechanism that prevents a change in frequency, effectively locking it.…”

Section: Discussionmentioning

confidence: 99%

High-Frequency TaO<sub><italic>x</italic></sub>-Based Compact Oscillators

Sharma¹,

Li²,

Skowroński³

et al. 2015

IEEE Trans. Electron Devices

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In this paper, we demonstrate three key features of oxide-based nano-oscillators: 1) the observation of threshold switching and filamentary oscillations in TaO x ; 2) the highest frequency achieved by oxide-based oscillators; and 3) a study with linear (resistor) and nonlinear (transistor) ballasts to clearly understand the role of filament dynamics in scaling. These oscillators show frequency tunability over the range of 20 kHz-250 MHz, with 250 MHz being the highest reported frequency for this class of oscillators. Different types of ballasts show frequency tunability using two distinct methods: 1) by tuning the channel resistance of the transistor and 2) by increasing the rail voltage across the ballast-device pair. This sheds new light on the oscillator dynamics for dense oscillator arrays aimed at oscillatory neural networks and other applications.Index Terms-One transistor, one resistor (1T1R), compact oscillator, filament dynamics, filament formation, forming, high frequency, metal-insulator transition, oscillatory neural network (ONN), oxide oscillators, resistive random access memory (RRAM), TaO x .

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“…[3][4][5]. Hardware implementations of oscillatory neural networks are based both on current CMOS devices (e.g., phase-locked loop circuits [6] or Van der Pol oscillators [7]) and on emerging new devices, such as, spin-torque nano-oscillators [8], switches based on materials with metal-insulator [1,9] or charge density wave [10,11] transitions, and oxide RRAM [12,13].…”

Section: Introductionmentioning

confidence: 99%

“…In an ONN, an elementary cell comprises an oscillator circuit, and the cells are locally coupled by resistors or capacitors [9][10][11][12][13]. Also, in the work [7], the variable resistive coupling via a memristive device has been proposed.…”

Section: Introductionmentioning

confidence: 99%

Thermal coupling and effect of subharmonic synchronization in a system of two VO2 based oscillators

Velichko

Belyaev

Putrolaynen

et al. 2018

Solid-State Electronics

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We explore a prototype of an oscillatory neural network (ONN) based on vanadium dioxide switching devices. The model system under study represents two oscillators based on thermally coupled VO2 switches. Numerical simulation shows that the effective action radius RTC of coupling depends both on the total energy released during switching and on the average power. It is experimentally and numerically proved that the temperature change ΔT commences almost synchronously with the released power peak and T-coupling reveals itself up to a frequency of about 10 kHz. For the studied switching structure configuration, the RTC value varies over a wide range from 4 to 45 μm, depending on the external circuit capacitance C and resistance Ri, but the variation of Ri is more promising from the practical viewpoint. In the case of a "weak" coupling, synchronization is accompanied by attraction effect and decrease of the main spectra harmonics width. In the case of a "strong" coupling, the number of effects increases, synchronization can occur on subharmonics resulting in multilevel stable synchronization of two oscillators. An advanced algorithm for synchronization efficiency and subharmonic ratio calculation is proposed. It is shown that of the two oscillators the leading one is that with a higher main frequency, and, in addition, the frequency stabilization effect is observed. Also, in the case of a strong thermal coupling, the limit of the supply current parameters, for which the oscillations exist, expands by ~ 10 %. The obtained results have a universal character and open up a new kind of coupling in ONNs, namely, T-coupling, which allows for easy transition from 2D to 3D integration. The effect of subharmonic synchronization hold promise for application in classification and pattern recognition.

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High performance, integrated 1T1R oxide-based oscillator: Stack engineering for low-power operation in neural network applications

Cited by 10 publications

References 0 publications

Compact oscillation neuron exploiting metal-insulator-transition for neuromorphic computing

Compact oscillation neuron exploiting metal-insulator-transition for neuromorphic computing

High-Frequency TaO<sub><italic>x</italic></sub>-Based Compact Oscillators

Thermal coupling and effect of subharmonic synchronization in a system of two VO2 based oscillators

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