Circuit arrangement for cooling of surface mounted semi-conductors

• US 20060061969A1
• Filed: 09/16/2005
• Published: 03/23/2006
• Est. Priority Date: 09/20/2004
• Status: Abandoned Application

• Current Assignee: Danaher Motion Stockholm AB (Danaher Corporation)
• Original Assignee: Danaher Motion Stockholm AB (Danaher Corporation)
• Inventors: Karlsson, Ulf Bengt Ingemar, Nilson, Thord Agne Gustaf, Ro, Ola, Rocklinger, Erik Hakan, Berglund, Jan Anders, Forborgen, Carl Erik Mikael
• Application Number:
  US11/228,886
• Publication Number:
  US 20060061969A1
• Time in Patent Office: Days
• US Class Current: 361/704
• CPC Class Codes: H05K 1/0204 using means for thermal conduction connection in the thickness direction of the substrate H05K1/0207 takes precedence
• CPC Class Codes: H05K 2201/10166 Transistor
• CPC Class Codes: H05K 2201/10416 Metallic blocks or heatsinks completely inserted in a PCB metallic supports H05K3/0061
• CPC Class Codes: H05K 3/0061 onto a metallic substrate, e.g. a heat sink heat sinks for electric apparatus H05K7/20
• CPC Class Codes: H05K 7/209 Heat transfer by conduction from internal heat source to heat radiating structure H05K7/20909 takes precedence

Abstract

A circuit arrangement comprises a circuit board (10), a semi-conductor (12) provided on a first side of the circuit board, and a heat sink (15) provided on a second side of the circuit board opposite to the first side and in heat transferring contact with the power semi-conductor. A heat conductive element (13) is provided in a hole (10a) in the circuit board, wherein the heat conductive element is positioned in heat transferring contact with both the semi-conductor and the heat sink for transfer of heat generated by the semi-conductor to the heat sink. A circuit arrangement is provided, wherein the provision of a low thermal resistance path through the circuit board by means of heat conductive elements provides a compact circuit arrangement well suited for assembly by means of an automated surface mounting process.

Claims

1. A circuit arrangement, comprising:

a circuit board;

a semi-conductor provided on a first side of the circuit board,

a heat sink provided on a second side of the circuit board opposite to the first side and in heat transferring contact with the power semi-conductor,

a heat conductive element provided in a through hole in the circuit board, wherein the heat conductive element is positioned in heat transferring contact with both the semi-conductor and the heat sink for transfer of heat generated by the semi-conductor to the heat sink,

wherein the heat conductive element comprises a flange locating the heat conductive element in the hole, and

wherein the flange extends on the first side of the circuit board.

2. The circuit arrangement according to claim 1, wherein the upper surface of the heat conductive element is flush with the upper surface of the circuit board.

3. The circuit arrangement according to claim 1, comprising a heat conductive electrical insulator between the heat conductive element and the heat sink.

4. The circuit arrangement according to claim 1, comprising a plurality of semi-conductor elements and a heat conductive element in heat transferring contact with the plurality of semi-conductors.

5. The circuit arrangement according to claim 1, wherein the semi-conductor is soldered by means of solder or glued by means of a thermally conductive glue to the heat-conductive element.

6. The circuit arrangement according to claim 1, wherein the heat conductive element is used as electrical connection to the semi-conductor.

7. The circuit arrangement according to claim 1, comprising a clamp bar on the first side of the circuit board and being connected to the heat sink, preferably by means of a screw joint, so that a clamping force is applied on the semi-conductor, the heat conductive element and the heat sink.

8. The circuit arrangement according to claim 1, wherein the heat conductive element is made of a material chosen from the group comprising copper and aluminum and alloys thereof.

9. The circuit arrangement according to claim 1, wherein the semi-conductor is in the form of a To263 package.

10. The circuit arrangement according to claim 1, wherein the circuit board is a flame retardant board, such as an FR4 board.

11. A method of assembling a circuit arrangement with a circuit board, a semi-conductor, and a heat sink, the method comprising the following steps:

providing a through hole in the circuit board;

providing a heat conductive element in the through hole;

providing the semi-conductor in heat transferring contact with the heat conductive element on a first side of the-circuit board;

electrically connecting the semi-conductor to the circuit board; and

applying the heat sink in heat conducting contact with the heat conductive element on a second side of the circuit board;

wherein the step of providing a heat conductive element comprising positioning the heat conductive element by means of a flange; and

wherein the heat conductive element is provided in the hole from the first side of the circuit board.

12. The method according to claim 11, wherein the step of providing the semi-conductor comprises placing a solder pre-f omm onto the heat conductive element.

13. The method according to claim 11, wherein the step of providing a heat conductive element comprises positioning the heat conductive element by means of press fit.

14. The method according to claim 11, wherein the step of connecting the semi-conductor to the circuit board comprises soldering by means of solder or gluing by means of electrically conductive glue.

15. The method according to claim 11, comprising the additional step of applying solder material by means of screening or deposition.

16. The method according to claim 11, comprising the additional step of applying a heat conductive electrical. insulator between the heat conductive element and the heat sink.