Operational amplifier protection circuit using, either in working conditions or at start-up, identical circuit elements for detecting permanent output abnormal conditions.

摘要

Circuit for protection of an amplifier stage comprising circuit switching means (G) for turn-off of the stage and piloted through a logic gate OR (F) by a monostable (M), which generates upon arise of abnormal operating conditions turn-off command signals having a predetermined duration. A sensing circuit (B) upon persistence of abnormal conditions at start-up or during normal operation also sends turn-off signals through the logic gate OR (F) after enablement through a gate AND (H). The signals of any enablement at the logic gate AND arrive through a logic gate OR (C) from a window comparator (A) coupled with stage start-up members, from the monostable, and from the output of said logic gate AND (H) as a confirmation signal.