Thermal protection device for an integrated power MOS

A thermal protection device for a power MOSFET comprising an interdigitated array of source regions and drain regions defined in a well region of a substrate, and gates associated with channel regions defined between adjacent source and drain regions, the thermal protection device comprising:

• a circuit for forcing a first fixed current through at least one source region separately connected from other source regions of the interdigitated array of source regions;
• and
• a comparator, integrated on the substrate outside the well region, comparing a source voltage on the at least one source region with a threshold voltage for outputting an over temperature flag signal for turning off the power MOSFET when overheated.

A method for thermal protection of a power MOSFET comprising an interdigitated array of source regions and drain regions defined in a well region of a substrate, and gates associated with channel regions defined between adjacent source and drain regions, the method comprising:

• forcing a first current through a first number of source regions separately connected from other source regions of the interdigitated array of source regions;
• and
• comparing a source voltage on the first number of source regions with a threshold voltage for turning off the power MOSFET when overheated.