Circuit Arrangement and Method for Detecting the State of a Circuit Protection Element

A circuit arrangement to detect a state of a circuit-protection element, comprising:

• the circuit-protection element having a resistance, wherein the resistance depends on the voltage on the protection element, wherein in a first voltage range a flow of current and a voltage change are in synchronism to one another, and, in a second voltage range the flow of current and voltage change in opposite directions to one another;
• a detection unit to detect at least one potential or one voltage on the protection element, or to detect a current flowing through the protection element;
• a specification unit to make a potential modification or a voltage modification on the protection element, or to make a modification to the current through the protection element;
• and
• an evaluation unit connected on an input side to an output of the detection unit, wherein the evaluation unit generates an evaluation output based upon an output of the detection unit, and based upon at least one modification initiated by the specification unit, and wherein the generated output signal specifies a opposite sign or a same sign of the voltage and the current on the protection element.

A method for detecting a state of a protection element, comprising:

• detecting a first current flow through the protection element with a first voltage on the protection element;
• modifying the voltage on the protection element;
• detecting a second current flow through the protection element based upon the modified voltage;
• and
• determining the change between the currents.

A method for detecting the state of a protection element, comprising:

• detecting a first voltage on the protection element with a first current through the protection element;
• modifying the first current;
• and
• detecting of a second voltage on the protection element based upon the modified current;
• determining the change of the voltage.