# US 2008/0186681 A1 · Electronic assembly cooling > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2008/0186681 A1 - Document ID: US20080186681A1 - Status: Published application - Kind: A1 - Application number: 12/019,712 - Filed: 2008-01-25 - Published: 2008-08-07 - Earliest claimed: 2007-02-02 - Assignees: Bose Corporation - Inventors: Joseph F. Deck; Bradley L. Hunter; Michael Nussbaum; Steven D. Owen - Web page: https://patentgrep.com/patent/US20080186681A1 ## CPC - H05K 7/2049: {Pressing means used to urge contact, e.g. springs} - H10W 40/611: {Bolts or screws} - H10W 40/235: {attached to package parts} - H10W 40/625: {Clamping parts not primarily conducting heat} - H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 ## Abstract An electronic assembly including a first heat producing device mounted on a first outer surface of a first portion of a circuit board. The first portion can deflect upwardly and downwardly relative to other portions of the circuit board. A first force element urges the first heat producing device against a heat sink. The force exerted by the first force element is variable with respect to time. ## Claims ### Claim 1 An electronic assembly, comprising: a first heat producing device mounted on a first outer surface of a first portion of a circuit board, wherein the first portion can deflect upwardly and downwardly relative to other portions of the circuit board; and a first force element for urging the first heat producing device against a heat sink, wherein the force exerted by the first force element is variable with respect to time. ### Claim 2 (depends on 1) An electronic assembly according to claim 1, wherein the first portion of the circuit board is a cantilevered projection. ### Claim 3 (depends on 1) An electronic assembly according to claim 1, wherein the first force element is a compressible foam. ### Claim 4 (depends on 1) An electronic assembly according to claim 1, wherein the first force element is a silicone spring. ### Claim 5 (depends on 1) An audio amplifier according to claim 1, wherein the silicone spring has a negative spring rate over a portion of its displacement. ### Claim 6 (depends on 1) An electronic assembly according to claim 1 further comprising a second heat producing device mounted on a first outer surface of a second portion of the circuit board; wherein the first and second portions can deflect upwardly and downwardly relative to each other and to other portion of the circuit board; and a second force element for urging the second heat producing device against a heat sink; wherein the force exerted by the second force element is variable with respect to time. ### Claim 7 (depends on 6) An electronic assembly according to claim 6 wherein the first force element and the second force element comprise a silicone spring. ### Claim 8 (depends on 7) An electronic assembly according to claim 7, wherein the silicone spring has a negative spring rate over a portion of its displacement. ### Claim 9 (depends on 6) An electronic assembly according to claim 6, wherein the first force element and the second force element are different areas of a compressible pad. ### Claim 10 (depends on 6) An electronic assembly according to claim 6, wherein the first force element and the second force element comprise compressible pads. ### Claim 11 (depends on 10) An electronic assembly according to claim 10, wherein the compressible pads comprise silicone foam. ### Claim 12 (depends on 1) An electronic assembly according to claim 1, wherein the first force element exerts the force against a second outer surface of the first portion opposite the first outer surface. ### Claim 13 (depends on 1) An electronic assembly according to claim 1, wherein the first force element has a property that if subjected to a temperature of 125° C. for 1522 hours, the first force element exerts a pressure that is less than 75% of an initial pressure. ### Claim 14 (depends on 1) An electronic assembly according to claim 1, wherein the first force element has a property that if subjected to a temperature of 125° C. for 1522 hours, the first force element exerts a pressure that is less than 45% of an initial pressure. ### Claim 15 An audio amplifier comprising: a first power amplifier chip mounted on a first outer surface of a first portion of a circuit board; a second power amplifier chip mounted on the first outer surface of a second portion of the circuit board so that the first portion and the second portion can deflect upwardly and downwardly relative to each other; and a force source comprising a non-metallic material adjacent a second outer surface of a circuit board to urge the first power amplifier chip and the second amplifier chip against a heat sink with a force that is variable with respect to time. ### Claim 16 (depends on 15) An audio amplifier according to claim 15, wherein the force source comprises a silicone spring. ### Claim 17 (depends on 16) An audio amplifier according to claim 16, wherein the silicone spring has a negative spring rate over a portion of its displacement. ### Claim 18 (depends on 15) An audio amplifier according to claim 15, wherein the force source comprises a sheet of silicone foam. ### Claim 19 (depends on 15) An audio amplifier according to claim 15, wherein the force source has a property that if subjected to a temperature of 125° C. for 1522 hours, the force element exerts a pressure that is less than 75% of an initial pressure. ### Claim 20 (depends on 15) An audio amplifier according to claim 15, wherein the compressible pad has a property that if subjected to a temperature of 125° C. for 1522 hours, the force element exerts a pressure that is less than 45% of an initial pressure. ### Claim 21 (depends on 6) An electronic assembly according to claim 6, wherein the first force element and the second force element comprise silicone springs. ### Claim 22 (depends on 21) An electronic assembly according to claim 21, wherein each of the silicone springs have a negative spring rate over a portion of the displacement.