US 7,321,484 B2
Providing accurate detection of chip overheat and local overheat conditions in integrated circuits
S. M. Sohel Imtiaz, San Jose, Calif. (US)
Assigned to Micrel, Incorporated, San Jose, Calif. (US)
Filed on Jun. 24, 2005, as Appl. No. 11/165,712.
Prior Publication US 2006/0291123 A1, Dec. 28, 2006
Int. Cl. H02H 5/04 (2006.01)
U.S. Cl. 361—103 19 Claims
OG exemplary drawing
 
1. A thermal shutdown system for an integrated circuit (IC), the thermal shutdown system comprising:
a first shutdown circuit triggered by a chip overheat condition, the first shutdown circuit including a first set of bipolar transistors sensitive to the chip overheat condition;
a second shutdown circuit triggered by a local overheat condition, the second shutdown circuit including a second set of bipolar transistors sensitive to the local overheat condition; and
a feedback signal provided to the first shutdown circuit and the second shutdown circuit, the feedback signal being temperature independent and able to anticipate the local overheat condition, wherein one of the first and second shutdown circuits inverts the feedback signal, and wherein the feedback signal enables one of the first and second shutdown circuits and disables the other.