Download or read book Development of CMOS Solid State Magnetic Sensors written by John G. Doyle and published by . This book was released on 2004 with total page 185 pages. Available in PDF, EPUB and Kindle. Book excerpt: A magnetic field sensor is a transducer that is capable of converting a magnetic field, H, into a useful electronic signal. These are used in a wide range of applications including retrieving data in the computer industry by reading magnetic tapes or disks or reading magnetic ink on banknotes, cashcards or credit cards for identification purposes, contactless switching, linear and angular displacement detection (e.g. in automotive systems) and potential-free current detection. A majority of solid state magnetic field sensors made to date have been built on bipolar processes. However, it would be beneficial to obtain similar levels of capability in magnetic sensors in CMOS, because this would allow magnetic sensors to be integrated into the present mainstream semiconductor technology. This thesis describes a research effort to improve the sensing capability of silicon magnetic field detectors through circuit innovation such that it is possible to develop a high performance, low power magnetic sensing capability in standard CMOS without extra exotic process steps or the requirement to have flux concentrators or other external devices in order to boost the sensing capability of the CMOS device. There are three circuits described in this work. The first, a magnetic sensitive amplifier achieved the highest figure of merit, 16kV/AT, reported at the time of its publication. The second device was the lowest power magnetic sensor at the time of its publication and could sense 1mT while running on 100nA. The third used a novel noise reduction scheme to sense lower levels of magnetic field (0.18mT) than had been reported for a CMOS device to date and provides a path to improved performance in future. The work in this thesis demonstrates that it is possible through circuit design innovation to deliver highly sensitive, low power magnetic sensors in standard CMOS.