Authors: W F Lee P K Chan
Publish Date: 2006/04/03
Volume: 47, Issue: 3, Pages: 247-257
Abstract
This paper presents two improved circuit techniques that allow the design of a lowcost programmable clock generator using a ring oscillator for lowfrequency switchedcapacitor applications The first technique aims at reducing the frequency of the oscillator with small capacitors by proposing a Miller currentstarved inverter ring oscillator For identical values of integrated components in implementation the proposed ring oscillator reduces the oscillation frequency by 5 times over the conventional ring oscillator and 3 times over the conventional currentstarved inverter ring oscillator This benefits the relaxation of PSRR requirement and the reduction of substrate noise coupling in mixedsignal circuits The second technique aims at enhancing the reliability of the programmed data by proposing orthogonal fusible link trimming circuit The experimental results have verified that the programming range of 56 kHz to 1042 MHz is achieved using discretestep tuning on small capacitor values from 0375 pF to 5625 pF together with frequency division by four divider stages whilst the jitter is less than 300 ps at ±10 variation in a 5 V supply in the entire tuning rangeWing Foon Lee was born in Singapore He had worked as an application engineer for more than two years He received his BEng MEng and PhD degrees in Electrical Electronic Engineering from Nanyang Technological University Singapore in 1996 1999 and 2005 respectively His research interest is on low power analog circuit design high precision readout circuits and signalconditioning circuits for sensor applicationsP K Chan was born in Hong Kong He received the BSc Hons degree from the University of Essex Colchester UK in 1987 the MSc degree from the University of Manchester Institute of Science and Technology UMIST Manchester UK in 1988 and the PhD degree from the University of Plymouth UK in 1992 From 1989 to 1992 he was a Research Assistant with the University of Plymouth working in the area of MOS continuoustime filters In 1993 he joined the Institute of Microelectronics IME as a Member Technical Staff where he designed CMOS sensor interfaces for industrial applications In 1996 He was a Staff Engineer with Motorola Singapore where he developed the magnetic write channel for Motorola 1st generation harddisk preamplifier He joined Nanyang Technological University NTU Singapore in 1997 where he is currently an Associate Professor in the School of Electrical and Electronic Engineering and Program Director analog/mixedsignal IC and applications for the Center for Integrated Circuits and Systems CICS He holds four patents and is an IC Design Consultant to local and multinational companies in Singapore He has also conducted numerous IC design short courses to the industrial companies and design centers His research interests include circuit theory amplifier frequency compensation techniques sensing interfaces for integrated sensors biomedical circuits and systems integrated filters and data converters
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