NCKU Associate Prof. Soon-Jyh Chang developed circuit design techniques of energy saving

TAINAN, TAIWAN: Associate Prof. Soon-Jyh Chang of Department of Electrical Engineering at National Cheng Kung University (NCKU), Tainan, Taiwan, has led a research team of doctoral students to develop three advanced circuit design techniques, which can consume the lowest energy in the world and save 80 percent of energy in comparison to the traditional design techniques.

The three circuit design techniques raised by the research team include monotonic capacitor switching procedure, binary-scaled error compensation method and binary-scaled error compensation method, which are able to improve the operating speed and achieve excellent energy efficiency.

With the first technique, the monotonic capacitor switching procedure, the average switching energy and total sampling capacitance are reduced by about 81.3 percent and 50 percent, respectively, compared to converters which use the conventional procedure.

The second technique, the binary-scaled error compensation method, can compensate for the DAC settling error since the DAC settling issue limits the operating speed of a SAR ADC, and it can perform comparison before the DAC is completely settled, resulting in improved operating speed.

The third technique, the binary-scaled error compensation method, uses a predictive circuit to avoid unnecessary switching in a DAC network, saves 40 percent to 45 percent switching energy and improves static and dynamic performance of a SAR ADC. Combined with the first technique, the average switching energy is reduced by about 90 percent than the conventional one.

The research achievements of the three design techniques have been published in international conferences, including IEEE International Solid-State Circuits Conference (ISSCC), the Oscar of the field of Integrated Circuit, Symposium VLSI Circuits, and DAC.

Applying the techniques, the research team of NCKU Department of Electrical Engineering, including the leader, Chun-Cheng Liu, and team members, Ying-Ju Lin and Kuan-Ying Huang, supervised by Associate Prof. Soon-Jyh Chang, has won the only Golden Jury Award with their design of high-speed high-energy-efficiency successive-approximation-register analog-to-digital converters and has received the prize of NT$150,000 from Yuan-Tseh Lee, honorary dean of Academic Sinica.

The 2010 Macronix Golden Silicon Awards, a contest on the application and design of semiconductors, is an important benchmarking contest for both industries and National Cheng Kung University, primarily based on scientific and technological originality and the value of semiconductors in terms of their application.