# US 5,710,515 A · Non-volatile memory in power and linear integrated circuits > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,710,515 A - Document ID: US5710515A - Status: Granted - Kind: A - Application number: 08/480,063 - Filed: 1995-06-07 - Granted: 1998-01-20 - Earliest claimed: 1993-08-27 - Assignees: Texas Instruments Incorporated - Inventors: Ross E. Teggatz; Joseph A. Devore; Stephen L. Sutton; Ganapathy R. Subramaniam - Web page: https://patentgrep.com/patent/US5710515A ## CPC - H10W 40/00: Arrangements for thermal protection or thermal control (integrated devices comprising arrangements for thermal protection H10D89/60) - G01K 7/01: using semiconducting elements having PN junctions (G01K7/02, G01K7/16, G01K7/30 take precedence) - G01R 31/30: Marginal testing, e.g. by varying supply voltage (testing computers during standby operation or idle time G06F11/22) - G01R 31/3167: Testing of combined analog and digital circuits {(testing ADC's H03M1/1071)} - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 - G01K: MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR (radiation pyrometry G01J5/00) - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) ## Abstract A testable temperature warning circuit (120) in an integrated circuit substrate (124) provides a warning if the substrate temperature exceeds a critical temperature. A programming circuit (140) controls a selection, circuit (128) to establish a programmably selectable temperature at either the critical temperature or a second predetermined temperature lower than the critical temperature to enable the warning circuit operation to be tested at a temperature lower than the critical temperature. In one embodiment, the selection circuit 128 comprises a current source that produces a voltage drop across the resistor 121 and base-emitter of the transistor 122 produces a substrate temperature indicating current of magnitude related to the temperature of the substrate. The substrate temperature indicating current at the second temperature is extrapolatingly related to the substrate temperature indicating current at the critical temperature. A method is also presented for testing a temperature warning circuit fabricated in an integrated circuit substrate. ## Claims ### Claim 1 A temperature warning circuit for testing an integrated circuit without damaging the integrated circuit, comprising: a first circuit for generating a temperature warning signal if a temperature of the integrated circuit exceeds a predetermined first temperature; a second circuit for generating a temperature warning signal if a temperature of the integrated circuit exceeds a predetermined second temperature, said second temperature being less than said first temperature, said second temperature being related to said first temperature whereby if an extrapolation is made between said first and second temperatures, the first and second warnings can be similarly extrapolated; a selection circuit for programmably selecting between said said first and second circuits for operation. ### Claim 2 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. ### Claim 3 (depends on 2) The circuit of claim 2 wherein said first predetermined threshold temperature is a temperature above which operation of a circuit on said substrate is not desired, and said second predetermined threshold temperature is a temperature lower than said first predetermined threshold temperature. ### Claim 4 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. ### Claim 5 (depends on 4) The warning circuit of claim 4 wherein said externally programmable circuit is a non-volatile memory. ### Claim 6 (depends on 5) The warning circuit of claim 5 wherein said non-volatile memory comprises EPROM devices connected to control the selection circuit to establish said programmably selectable temperature. ### Claim 7 (depends on 4) The warning circuit of claim 4 wherein said critical temperature is a temperature above which operation of an operating circuit on said substrate is not desired. ### Claim 8 (depends on 4) The warning circuit of claim 4 wherein said selection circuit comprises a current source that produces a substrate temperature indicating current of magnitude related to the temperature of said substrate. ### Claim 9 (depends on 8) The warning circuit of claim 8 wherein said substrate temperature indicating current at said second temperatures is extrapolatedly related to said substrate temperature indicating current at said critical temperature. ### Claim 10 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. ### Claim 11 (depends on 10) The method of claim 10 wherein said programming circuit is an externally programmable non-volatile memory. ### Claim 12 (depends on 11) The method of claim 11 wherein said externally programmable non-volatile memory comprises EPROM devices. ### Claim 13 (depends on 10) The method of claim 10 wherein said critical temperature is a temperature above which operation of an operating circuit on said substrate is not desired. ### Claim 14 (depends on 10) The method of claim 10 wherein said step of providing a warning circuit comprises providing a current source that produces a substrate temperature indicating current of magnitude related to the temperature of said substrate. ### Claim 15 (depends on 14) The method of claim 14 wherein the magnitude of the indicating current that produces a warning at said lower temperature is extrapolatedly related to the current that would produce a warning at said critical temperature.