Current limiting device

A current limiting device, comprising:

• a first current limiting unit configured to limit an electric current equal to or higher than a first threshold value applied thereto;
• a second current limiting unit configured to limit an electric current equal to or higher than a second threshold value applied thereto;
• and
• a passive element unit connected to both ends of the first current limiting unit, and including a first passive element and a second passive element connected in series,
• wherein the second current limiting unit is connected to the first passive element in parallel,
• an impedance value of the first current limiting unit and an impedance value of the second current limiting unit are changed by an electric current applied thereto,
• the applied electric current flows through the first current limiting unit when the applied electric current is less than the first threshold value,
• the applied electric current flows through the second current limiting unit and the second passive element when the applied electric current is equal to or higher than the first threshold value and less than the second threshold value, and
• the applied electric current flows through the passive element unit when the applied electric current is equal to or higher than the second threshold value.