Non-volatile memory in power and linear integrated circuits

A circuit for testing for a temperature of an integrated circuit substrate, fabricated in said substrate and comprising:

• a circuit for generating a warning if the temperature of the substrate reaches a programmably selectable threshold temperature;
• an externally programmable and reprogrammable non-volatile memory;
• and
• a circuit responsive to the contents of said non-volatile memory for establishing said threshold temperature at either a first or a second predetermined threshold temperature.

A testable warning circuit fabricated in an integrated circuit substrate for providing a warning if a temperature of said substrate exceeds a critical temperature, comprising:

• a circuit for generating a warning if the temperature of the substrate exceeds a programmably selectable temperature;
• an externally programmable and reprogrammable circuit;
• and
• a selection circuit responsive to said externally programmable circuit for establishing said programmably selectable temperature at either said critical temperature for a normal operation or a second predetermined temperature lower than said critical temperature for testing whether said warning circuit is operating.

A method for operating a temperature warning circuit fabricated in an integrated circuit substrate, said warning circuit being intended to produce a warning if a temperature of said substrate exceeds a critical temperature, comprising:

• providing a warning circuit;
• providing a programming circuit in said substrate connected to select a temperature at which said warning circuit is activated to produce a warning;
• altering said programming circuit to select a lower temperature than said critical temperature for activating said warning circuit;
• increasing a temperature of said substrate to a test temperature at said lower temperature;
• determining whether said warning circuit is activated at said test temperature;
• and
• altering said programming circuit to select said critical temperature for activating said warning circuit.