Trigger circuit and method for improved transient immunity

An integrated circuit comprising:

• a clamping device;
• and
• a trigger circuit for detection of a transient voltage increase on the integrated circuit, the trigger circuit controlling a conductivity state of the clamping device to limit the transient voltage increase, wherein the trigger circuit controls the clamping device to provide higher conductivity when the integrated circuit is in an unpowered state and controlled lower conductive to provide voltage regulation when the integrated circuit is in a powered state, the trigger circuit comprising:
• 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 the unpowered state of the integrated circuit and the second time value applicable to the powered state of the integrated circuit, wherein the first time value and the second time value control a trigger circuit parameter selected from a group consisting of:
• a detection range within which a rate of transient voltage increase causes the trigger circuit to become active;
• and
• an “on” time upon which an active duration of the controlling of the conductivity state of the clamping device depends.

A method comprising:

• selecting a first value of a variable of a linear time-invariant (LTI) function for an unpowered state of an integrated circuit and a second value of the variable of the linear time-invariant (LTI) function for a powered state of the integrated circuit, wherein the first value and the second value are dependent upon a common reactive element;
• detecting a transient voltage increase on the integrated circuit;
• and
• controlling a conductivity state of a clamping device to limit the transient voltage increase, wherein the controlling is dependent upon the LTI function and wherein the controlling occurs for an active duration, the active duration being dependent upon the LTI function.