Power converter assembly

• US 6,549,409 B1
• Filed: 08/21/2000
• Issued: 04/15/2003
• Est. Priority Date: 08/21/2000
• Status: Expired due to Term

• Current Assignee: Vicor Corporation
• Original Assignee: VLT Incorporated (Vicor Corporation)
• Inventors: Evans, Michael D., Vinciarelli, Patrizio, Saxelby, John R. Jr.
• Primary Examiner(s): CHERVINSKY, BORIS LEO
• Application Number:
  US09/643,159
• Time in Patent Office: 967 Days
• Field of Search: 361/704, 361/707, 361/715, 361/717-721, 361/723, 361/761, 174/52.2, 174/52.4, 174/52.3, 257/687, 257/706, 257/707, 257/787, 257/796, 165/80.2, 165/185
• US Class Current: 361/704
• CPC Class Codes: H01L 2224/05553 being rectangular
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/13091 Metal-Oxide-Semiconductor Field-Effect Transistor [MOSFET]
• CPC Class Codes: H05K 1/0203 Cooling of mounted components H05K1/0272 takes precedence
• CPC Class Codes: H05K 2201/1056 Metal over component, i.e. metal plate over component mounted on or embedded in PCB
• CPC Class Codes: H05K 2201/10734 Ball grid array [BGA]; Bump grid array
• CPC Class Codes: H05K 3/284 for encapsulating mounted components H05K1/185 takes precedence
• CPC Class Codes: H05K 5/064 sealed by potting, e.g. waterproof resin poured in a rigid casing
• CPC Class Codes: H05K 7/209 Heat transfer by conduction from internal heat source to heat radiating structure H05K7/20909 takes precedence

Abstract

A power converter assembly includes a heat sinking plate, a circuit board structure having a side that faces and is spaced by a gap from a surface of the heat sinking plate that is nearer to said side, a relatively thin, high heat density, dissipative semiconductor component mounted on said side, an encapsulating material filling the gap, and relatively taller, lower heat density, components mounted on the other side of the circuit board, the gap being characterized by an average thermal-resistance of less than 1° C.−in²/Watt.

Claims

1. A power converter assembly comprising

a heat sinking plate,

a circuit board structure comprising a circuit board having a first side and a second side, wherein the first side faces and is spaced by a gap from a surface of the heat sinking plate that is nearer to said first side,

a dissipative semiconductor component mounted on said first side, and

an encapsulating material filling the gap,

the gap being characterized by an average thermal-resistance of less than 3°

C.−

in2/Watt.

2. The power converter assembly of claim 1 in which the heat sinking plate is planar.

3. The power converter assembly of claim 1 in which the circuit board is planar and holds power conversion elements of a power converter circuit.

4. The power converter assembly of claim 3 in which the power conversion elements include a transformer having a core and in which no portion of the core lies in the gap.

5. The power converter assembly of claim 3 in which the power conversion elements include the semiconductor component.

6. The power converter assembly of claims 1 or 5 in which the semiconductor component comprises a MOSFET.

7. The power converter assembly of claims 1 or 5 in which the semiconductor component comprises a diode.

8. The power converter assembly of claim 1 in which the average thermal resistance is less than 2°

C.−

in²/Watt.

9. The power converter assembly of claim 1 in which the average thermal resistance is less than 1°

C.−

in²/Watt.

10. A power converter assembly comprising

a heat sinking plate,

a circuit board structure comprising

a circuit board having a first side and a second side, wherein the first side faces and is spaced by a gap from a surface of the heat sinking plate that is nearer to said first side, and

components on the circuit board comprising a semiconductor component mounted on the first side of the circuit board,

a power conversion circuit comprising the components and being capable of accepting power from a source and delivering power to a load,

the circuit board dividing the total volume occupied by the assembly into a gap volume between the circuit board and the plate, and a remaining volume, the gap volume being no more than 25% of the total volume.

11. The power converter assembly of claim 10 in which the heat sinking plate is planar.

12. The power converter assembly of claim 11 in which the components include a transformer having a core and in which no portion of the core lies in the gap.

13. The power converter assembly of claims 10 or 12 in which the semiconductor component comprises a MOSFET.

14. The power converter assembly of claims 10 or 12 the semiconductor component comprises a diode.

15. The power converter assembly of claim 10 in which the gap volume is no more than 15% of the total volume.

16. The power converter assembly of claim 10 in which the gap volume is no more than 10% of the total volume.

17. A power converter assembly comprising

a heat sinking plate,

a circuit board structure comprising

a circuit board having a first side and a second side, wherein the first side faces and is spaced by a gap from a surface of the heat sinking plate that is nearer to said first side, and

components on the circuit board comprising a heat dissipating semiconductor component mounted on the first side of the circuit board, and

a power conversion circuit comprising the components and being capable of accepting power from a source and delivering power to a load,

the gap having a gap volume that is enclosed by (a) the surface of the heat sinking plate, (b) the first side of the circuit board, and (c) a perimeter surface that connects (a) and (b) along a perimeter of the overlap of (a) and (b) and which extends perpendicular to, and upward from, the surface of said heat sinking plate,

an upper volume that is enclosed by (a) the surface of the heat sinking plate, (b) an imaginary plane that is parallel to and spaced above the second side of the circuit board, the plane being tangent to the top of a component without intersecting any other component, and (c) the perimeter surface,

the gap volume being no more than 25% of the upper volume.

18. The power converter assembly of claim 17 in which the heat sinking plate is planar.

19. The power converter assembly of claim 17 in which the components include a transformer having a core and in which no portion of the core lies in the gap.

20. The power converter assembly of claims 17 or 19 in which the semiconductor component comprises a MOSFET.

21. The power converter assembly of claims 17 or 19 which the semiconductor component comprises a diode.

22. The power converter assembly of claim 17 in which the gap volume is no more than 15% of the upper volume.

23. The power converter assembly of claim 17 in which the gap volume is no more than 10% of the upper volume.

24. A power converter assembly comprising

a heat sinking plate,

a circuit board structure comprising

a circuit board having a first side and a second side, wherein the first side faces and is spaced by a gap from a surface of the heat sinking plate that is nearer to said first side, and

components on the circuit board comprising a heat dissipating semiconductor component mounted on the first side of the circuit board, and

a power conversion circuit comprising the components and being capable of accepting power from a source and delivering power to a load,

such that, for any imaginary volume consisting of:

a partial gap volume that is enclosed by (a) a portion of the surface of the heat sinking plate within an area of overlap between the circuit board and the baseplate, (b) the first side of the circuit board, and (c) a partial periphery surface which extends upward from the periphery of the portion of the surface of the heat sinking plate and which is perpendicular to the surface of the heat sinking plate, and

a partial upper volume that is enclosed by (a) the portion of the surface of the heat sinking plate, (b) an imaginary plane that is parallel to and spaced above the second side of the circuit board, the plane being tangent to the top of a component without intersecting any other component, and (c) the partial periphery surface,

the partial gap volume being no more than 25% of the partial upper volume.

25. The power converter assembly of claim 24 in which the heat sinking plate is planar.

26. The power converter assembly of claim 24 in which the components include a transformer having a core and in which no portion of the core lies in the gap.

27. The power converter assembly of claims 24 or 26 in which the semiconductor component comprises a MOSFET.

28. The power converter assembly of claims 24 or 26 in which the semiconductor component comprises a diode.

29. The power converter assembly of claim 24 in which the gap volume is no more than 15% of the upper volume.

30. The power converter assembly of claim 24 in which the gap volume is no more than 10% of the upper volume.

31. A power converter assembly comprising

a heat sinking plate,

a circuit board structure comprising

a circuit board having a first side and a second side wherein the first side faces and is spaced by a gap from a surface of the heat sinking plate that is nearer to said first side, and

components on the circuit board comprising a heat dissipating semiconductor component mounted on the first side of the circuit board and a magnetic power conversion component having a permeable core, and in which no part of the permeable core faces the first side of the circuit board, and

a power conversion circuit comprising the components that is capable of accepting power from a source and delivering power to a load.

32. The power converter assembly of claim 31 in which the heat sinking plate is planar.

33. The power converter assembly of claims 31 or 32 in which the semiconductor component comprises a MOSFET.

34. The power converter assembly of claims 31 or 32 in which the semiconductor component comprises a diode.

35. The power converter assembly of claim 31 in which the gap comprises gap volume which is no more than 25% of an upper volume.

36. The power converter assembly of claim 31 in which the gap comprises a gap volume which is no more than 15% of an upper volume.

37. The power converter assembly of claim 31 in which the gap comprises a gap volume which is no more than 10% of an upper volume.

38. A power converter assembly comprising

a heat sinking plate,

a circuit board structure comprising a circuit board having a first side that faces and is spaced by a gap from a surface of the heat sinking plate that is nearer to said side, and a second side,

a power conversion circuit comprising components on the first and second sides of said circuit board including a heat dissipating power conversion circuit element on the first side, and being capable of accepting power from a source and delivering power to a load,

the circuit board dividing the total height occupied by the assembly into a gap height and a remaining height,

the gap height being the average distance, over the area of the circuit board, between the surface of the heat sinking plate and the first side of the circuit board,

the remaining height being the distance between the second side of the circuit board and an imaginary plane that is parallel to and spaced above the second side, the plane being tangent to the top of a component without intersecting any other component,

the gap height being no more than 25% of the total height.

39. The power converter of claim 38 in which the gap height is no more than 15% of the total height.

40. The power converter of claim 38 in which the gap height is no more than 10% of the total height.

42. The power converter of claim 38 in which the gap height is no more than 15% of the total height.

43. The power converter of claim 38 in which the gap height is no more than 10% of the total height.

41. A power converter assembly comprising

a heat sinking plate having a surface,

a circuit board structure comprising a circuit board having a first side and a second side, wherein the first side faces and is spaced by a gap from a surface of the heat sinking plate that is nearer to said first side, and

a power conversion circuit comprising components on the first and second sides of said circuit board including a heat dissipating power conversion circuit element on the first side, and being capable of accepting power from a source and delivering power to a load,

the gap having a gap height between the surface of the heat sinking plate and the first side of the circuit board,

a total height being defined as the distance between the surface of the heat sinking plate and an imaginary surface that is parallel to the surface of the heat sinking plate and touches a point on any of the components that is farthest away from the surface of the heat sinking plate,

the gap height being no more than 25% of the total height.

44. An electronic circuit assembly comprising

electronic components including (a) relatively higher heat-density heat-generating components having relatively lower heights, and comprising (b) relatively lower heat-density heat-generating components having relatively taller heights,

a metal base plate,

a circuit board in the vicinity of the metal base plate, the electronic components being mounted on the circuit board, at least some of the higher heat-density lower-height components being mounted on a side of the circuit board that faces the base plate, and the lower heat-density, taller-height components all being mounted on another side of the circuit board facing away from the base plate,

an encapsulant in a gap between the circuit board and the base plate, the encapsulant effecting an average thermal resistance of less than 3°

C.−

in²/Watt across the gap,

the circuit board dividing the total volume occupied by the assembly into a gap volume between the circuit board and the plate, and a remaining volume, the gap volume being no more than 25% of the total volume.

45. The power converter of claim 44 in which the average thermal resistance is less than 2°

C.−

in²/Watt across the gap.

46. The power converter of claim 44 in which the average thermal resistance is less than 1°

C.−

in²/Watt across the gap.