Over-current protection apparatus and method

An over-current protection apparatus comprising:

• a transistor disposed on a first substrate;
• a first thermal sense device arranged to sense a temperature reflective of a junction temperature of said transistor;
• a second thermal sense device arranged to sense a temperature reflective of a temperature of a casing surrounding said first substrate;
• and
• a control circuitry, wherein said control circuitry is arranged, to:
• responsive to said sensed temperature by said first thermal sense device and said sensed temperature of said second thermal sense device being indicative that the temperature difference between said transistor junction and the first substrate casing is greater than a predetermined value, switch said transistor to an off state;
• maintain said transistor in the off state after the temperature difference between said transistor junction and the first substrate casing is no longer greater than said predetermined value;
• and
• after a predetermined delay time and responsive to said sensed temperature by said first thermal sense device and said sensed temperature by said second thermal sense device being indicative that the temperature difference between said transistor junction and the first substrate casing is not greater than said predetermined value, switch said transistor to an on state.