Browsing by Author "Yang, Hsueh-Chih"

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A parallel-in folding technique for high-order FIR filter implementation
(2006-12-01)
Dung, Lan-Rong
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Yang, Hsueh-Chih
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電控工程研究所
;
Institute of Electrical and Control Engineering
This paper presents a hardware-efficient folding technique for high-order FIR filtering while considering the tradeoff between the number of processing elements and throughput rate. Given the throughput rate, one can always employ the minimum number of processing elements for saving the implementation cost and figure out a folded architecture. However, applying inefficient folding techniques may result in costly switches and registers. Therefore, our work intends to evaluate the efficiency for folding techniques in terms of the number of registers, and the power dissipation of registers. As shown in the estimation results, while comparing with the published folded architectures under the same throughput rate, the proposed folding technique can turn out less power dissipation and low hardware complexity than the others. The proposed design has been implemented using TSMC 0.18 mu m 1P6M technology. As seen in the post-layout simulation, our design can meet the requirement of IS-95 WCDMA pulse shaping FIR filter while the power consumption can be as low as 16.66 mW.
An accurate lithium-ion battery gas gauge using two-phase STC modeling
(2007)
Yang, Hsueh-Chih
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Dung, Lan-Rong
;
電控工程研究所
;
Institute of Electrical and Control Engineering
The lithium-ion (Li-ion) battery is a time-varying, nonlinear component. Its discharge characteristic is dependent on discharge current, loading change scheme, ambient temperature, and initial state-of-charge (SoC), and hence its remaining time can vary with the discharge operating conditions in a manner of nonlinear relationship. The non-linearity behavior makes the accurate gas-gauge of Li-ion battery very difficult. This paper presents an efficient scheme to simplify the estimation of battery service time with high-degree of accuracy. According to the typical discharge characteristic of Li-ion batteries, we applied a two-phase single-time-constant (STC) model for the gas-gauging strategy and parameterize the discharge operating conditions in terms of the first-phase gradient, the knee voltage, and the second-phase gradient, instead of using complex curve-fitting equations. As shown in the experimental results, the accuracy of predicted remaining time is less than 1% for constant current cases, and 10% for loading change cases.
On multiple-voltage high-level synthesis using algorithmic transformations
(2005)
Yang, Hsueh-Chih
;
Dung, Lan-Rong
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This paper presents a multiple-voltage high-level synthesis methodology for low power DSP applications using algorithmic transformation techniques. Our approach is motivated by maximization of task mobilities in that the increase of mobilities may raise the possibility of assigning tasks to lowvoltage components. The mobility means the ability to schedule the starting time of a task. It is defined as the distance between its as-late-as-possible (ALAP) schedule time and its as-soon-as-possible (ASAP) schedule time. To earn task -mobilities, we use loop shrinking, retiming and unfolding techniques. The loop shrinking can first reduce the iteration period bound (IPB) and, then, the others are employed for shortening the minimum achieved sample period (MASP) as much as possible. The minimization of MASP results in high task mobilities. Thereafter, we can assign tasks with high mobilities to low-voltage components and minimize energy dissipation under resource and latency constraints. With considering the overhead of level conversion, our approach can achieve significant power reduction. For instance, as the experimental results, we can save the power consumption up to 54.77% for the case of the third-order HR filter.