Trigger circuit and method for improved transient immunity

摘要

A trigger circuit detects a transient voltage increase on an integrated circuit. The trigger circuit controls a conductivity state of a clamping device to limit the transient voltage increase. The trigger circuit comprises a common capacitive element having a capacitive value, wherein a first time value and a second time value are dependent upon the capacitive value of the common capacitive element, the first time value applicable to an unpowered state of the integrated circuit and the second time value applicable to a powered state of the integrated circuit. The first time value and the second time value control a trigger circuit parameter which may include a detection range within which a rate of transient voltage increase causes the trigger circuit to become active or an “on” time upon which an active duration of control of the conductivity state of the clamping device depends.

主权项

1. A method comprising:
detecting a transient voltage increase on an integrated circuit; and controlling a conductivity state of a clamping device to limit the transient voltage increase, wherein at least one of the detecting and the controlling are dependent upon a first time value and a second time value, the first time value applicable to an unpowered state of the integrated circuit and the second time value applicable to a powered state of the integrated circuit, wherein the first time value and the second time value are dependent upon a capacitive value of a common capacitive element, wherein the controlling is dependent upon the first time value and the second time value and wherein the controlling occurs for an active duration, the active duration being dependent upon the first time value for the unpowered state of the integrated circuit and the second time value for the powered state of the integrated circuit.