Abstract: An apparatus for disabling a circuit when the circuit is in a first preselected condition includes a critical element that has an enable state and a disable state. The critical element is configured in relation to the circuit such that the circuit cannot operate normally if the critical element is in the disable state. A trigger generates a state signal that causes the critical element to enter the disable state when a comparison of a current condition to a stored value indicates that the circuit is in the first preselected condition. In a method of controlling operation of a circuit, a current condition is sensed. Whether the current condition corresponds to a stored value is determined. If the current condition corresponds to the stored value, then a critical element is caused to enter a disable state so that the circuit is prevented from operating normally.