Opto-coupler for digital signal transmission - uses control stage for counter-phase control of parallel elements

摘要

The opto-coupler for digital signal transmission between electrically separated circuits comprises two opto-coupler elements, (5, 7, 6, 8) suitable for use in hazardous areas, which are connected in a parallel circuit, preceded by a control stage (1) receiving the signals to be transmitted. The opto-coupler elements are operated in counter-phase, their phototransistors (7, 8) being connected in parallel in a differential circuit, their collectors are coupled to a common current source (9) and their emitters to respective inputs (15, 16) of a comparator (11) providing the output signal. USE/ADVANTAGE - Communication between intrinsically safe region, e.g. exposed to explosion or firedamp risk, h.v. or radiation treatment zone, and normal conditions region. Shorter switching times with normalised delays for switching on or off. Current saving with good temp. and long term stability.