Electronic assembly cooling
View Patent ↗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.
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, 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 and at least 33% of an initial pressure.
2. An electronic assembly according to claim 1 , wherein the first portion of the circuit board is a cantilevered projection.
3. An electronic assembly according to claim 1 , wherein the first force element is a compressible foam.
4. An electronic assembly according to claim 1 , wherein the first force element is a silicone spring.
5. An electronic assembly according to claim 4 , wherein the silicone spring has a negative spring rate over a portion of its displacement.
6. 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 second 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 and at least 33% of an initial pressure.
7. An electronic assembly according to claim 6 wherein the first force element and the second force element comprise a silicone spring.
8. An electronic assembly according to claim 7 , wherein the silicone spring has a negative spring rate over a portion of its displacement.
9. An electronic assembly according to claim 6 , wherein the first force element and the second force element comprise compressible pads.
10. An electronic assembly according to claim 9 , wherein the compressible pads comprise silicone foam.
11. 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.
12. 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 the initial pressure.
13. An electronic assembly according to claim 6 , wherein the first force element and the second force element comprise silicone springs.
14. An electronic assembly according to claim 13 , wherein each of the silicone springs have a negative spring rate over a portion of the displacement.
15. 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;
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
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; and
wherein the first force element and the second force element are different areas of a compressible pad.
16. 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,
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% and at least 33% of an initial pressure.
17. An audio amplifier according to claim 16 , wherein the force source comprises a silicone spring.
18. An audio amplifier according to claim 17 , wherein the silicone spring has a negative spring rate over a portion of its displacement.
19. An audio amplifier according to claim 16 , wherein the force source comprises a sheet of silicone foam.
20. An audio amplifier according to claim 16 , 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 the initial pressure.