| Abstract: | A simple methodology for implementation of low-order, current-mode, log-domain filters in CMOS technology is presented. The key transistors in the circuit are operated in weak inversion and in contrast with previous approaches may pass into the triode regime. The concept is particularly suited to implementation in silicon-on-insulator technology, because dielectric isolation of the transistors eliminates leakage currents, and because influence of the body effect on circuit function is limited. Very long time constants, on the order of 1 s or more, are obtainable. A simple elaboration of the basic unit circuit allows the time constant to be controlled by a bias current.Patrick Shoemaker received the B.A., M.S., and Ph.D. degrees in Bioengineering from the University of California, San Diego. From 1984 to 1998 he was an engineer with the Space and Naval Warfare Systems Center in San Diego, where he worked on modeling and implementation of artificial neural networks, and analog and mixed-signal circuit design. Since 1998 he has been with Tanner Research in Pasadena, California, where his work has focused on biological information processing (in particular, insect vision) and on biomimetic analog integrated circuits. Dr. Shoemaker is a member of the IEEE and the International Neural Network Society. |
