Browsing by Author "Lung, Sheng-Chi"

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0.4V Reconfigurable Near-Threshold TCAM in 28nm High-k Metal-Gate CMOS Process
(2018-01-01)
Chan, Yun-Sheng
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Huang, Po-Tsang
;
Wu, Shang-Lin
;
Lung, Sheng-Chi
;
Wang, Wei-Chang
This paper presents a near-threshold configurable ternary content addressable memory (TCAM) design for energy-constrained neural network or software-defined network (SDN) applications. A TCAM architecture based on foundry-based 6T SRAM mini-array improves area efficiency and minimizes disturbs to enable operation down to 0.4V, and provides configurable lookup tables for users. To minimize dynamic power consumption, hierarchical precharge structure (HPRE) and don't-care based ripple search-line scheme are utilized for decreasing both the switching activities and wire capacitance. Moreover, power-gating technique, self-timed control and V-trip-tracking write-assist are used to reduce standby power, speed-up propagation delays of global signals and improve write-ability at low voltage, respectively. A reconfigurable TCAM is implemented using UMC 28nm high-k metal gate (HKMG) CMOS process. The design achieves operating frequency of 240MHz (20MHz) with energy consumption of 1.146 (0.621) fJ/bit/search at 0.9V (0.4V).
28nm Near/Sub-Threshold Dual-Port FIFO Memory for Shared Queues in Multi-Sensor Applications
(2018-01-01)
Wu, Yi-Chun
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Huang, Po-Tsang
;
Wu, Shang-Lin
;
Lung, Sheng-Chi
;
Wang, Wei-Chang
For an energy-limited multi-sensing platform, ultra-low-power queueing design is one of the critical challenge to store low-speed sensing data with various sampling frequencies. In this paper, a near/sub-threshold dual-port first-in-first-out (FIFO) memory is proposed for shared queues in a unified queuing architecture. This ultra-lowpower FIFO memory is designed and implemented using bitinterleaved 12T near-/sub-threshold dual-port SRAM bit-cells, write/read-assist circuitries, and adaptive timing tracking circuits. The 12T bit-cell eliminates both read and write half-select disturbance. Additionally, an adaptive timing tracing circuitry and negative bit-line circuits are employed to against PVT variation and to enhance write ability, respectively. Furthermore, the self-timed pointers and short ripple bit-lines are designed to avoid global long metal lines with large loading. A 256x16 dual-port FIFO memory is implemented in UMC 28nm HKMG CMOS technology. This FIFO memory can be operated at 0.4V with 10MHz for read operations. Moreover, up to 60% power reduction can be achieved based on the proposed design techniques.
A 0.5-V 28-nm 256-kb Mini-Array Based 6T SRAM With Vtrip-Tracking Write-Assist
(2017-07-01)
Wu, Shang-Lin
;
Li, Kuang-Yu
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Huang, Po-Tsang
;
Hwang, Wei
;
Tu, Ming-Hsien
This paper presents a 28-nm 256-kb 6T static random access memory operating down to near-threshold regime. The cell array is built on foundry 4-by-2 mini-array with split single-ended large signal sensing to enable an ultra-short local bit-line of 4-b length to improve variation tolerance and performance, and to reduce disturb while maintaining manufacturability. The design employs threshold power gating to facilitate lower NAP (Sleep) mode voltage/power and faster wake-up for the cell array, and low-swing global read bit-line (GRBL) with integrated low-swing voltage precharger to improve read performance and reduce the dynamic read power. A cell Vtrip-tracking write-assist (VTWA) lowers the selected sub-array supply to cell inverter trip voltage to enhance write-ability while providing PVT tracking capability to ensure adequate data retention margin for unselected cells in the selected sub-array. The 256-kb test chip is implemented in UMC 28-nm high-kappa metal-gate (H kappa MG) CMOS technology with macro area of 1058.22 x 374.76 mu m(2). Error-free full functionality is achieved from 0.9 down to 0.5 V (limited by read VMIN) without redundancy. The low-swing GRBL reduces dynamic power by 6.5% (8.0%) at 0.9 V (0.6 V). The VTWA improves the write VMIN by 75 mV (from 0.525 to 0.45 V). The measured maximum operation frequency is 735 MHz (20 MHz) at 0.9 V (0.5 V), TT corner, 25(omicron).