Opto Isolation for Digital Input Circuits
Original Publication Date: 1987-Apr-01
Included in the Prior Art Database: 2005-Feb-01
A technique is described whereby a circuit may be attached to an existing digital input circuit board, so as to allow computers to receive signals which may contain high voltage transients. The concept is unique in that low voltage signal level computers may now receive high voltage signals directly, thereby eliminating the need to filter out or to convert the high voltage signals prior to entry into the computer. The circuit is designed to adapt to commercially available digital input/digital output (DI/DO) circuit boards, utilizing either separate isolation and driver modules or as a combined opto isolation/driver module. The circuit consists of opto isolation integrated circuit (IC) 10, as shown in the figure, resistor 11 and buffer/driver IC 12.