Circuit device and power conversion device

1. A circuit device comprising:

a printed circuit board having a first main surface and a second main surface opposite to the first main surface;

a core, the core including a first core portion positioned over the first main surface and spaced away from the first main surface and a second core portion positioned over the second main surface and spaced away from the second main surface, the core including a through portion passing between the first main surface and the second main surface,

the printed circuit board including at least one of a first coil pattern disposed on the first main surface and a second coil pattern disposed on the second main surface, the at least one of the first coil pattern and the second coil pattern surrounding the through portion of the core with half a turn or more,

the first coil pattern including a first portion arranged between the first core portion and the second core portion and a second portion exposed from at least one of the first core portion and the second core portion in a plain view from a direction vertical to the first main surface,

the second coil pattern including a third portion arranged between the first core portion and the second core portion and a fourth portion exposed from at least one of the first core portion and the second core portion in a plain view from a direction vertical to the second main surface; and

a first heat transfer member on at least one of the first portion and the third portion,

the first heat transfer member being mounted on the at least one of the first portion and the third portion,

the first heat transfer member being electrically connected to the at least one of the first portion and the third portion,

the first heat transfer member having a cross-sectional area larger than the at least one of the first portion and the third portion in a cross section crossing a direction in which current flows in the at least one of the first coil pattern and the second coil pattern,

the first heat transfer member having an electrical resistance lower than the at least one of the first portion and the third portion and being spaced away from the core.

2. The circuit device according to claim 1 , wherein the first heat transfer member is further disposed on at least one of the second portion and the fourth portion.

3. The circuit device according to claim 2 , wherein the first heat transfer member extends along the direction in which the current flows in the at least one of the first coil pattern and the second coil pattern, in the at least one of the second portion and the fourth portion.

4. The circuit device according to claim 1 , wherein the first heat transfer member is formed with a plurality of heat transfer portions.

5. The circuit device according to claim 1 , further comprising a heat dissipator thermally connected to at least one of the second portion and the fourth portion.

6. The circuit device according to claim 5 , wherein the heat dissipator forms a part of a housing accommodating the printed circuit board.

7. The circuit device according to claim 5 , further comprising a second heat transfer member having electrical insulation properties, wherein

the printed circuit board includes the first coil pattern, and

the second heat transfer member is disposed between the heat dissipator and the first coil pattern.

8. The circuit device according to claim 5 , further comprising a second heat transfer member having electrical insulation properties between the heat dissipator and the first heat transfer member.

9. The circuit device according to claim 7 , further comprising a plurality of mounting members configured to mount the printed circuit board on the heat dissipator, wherein

the plurality of mounting members are disposed along a longitudinal direction of the second heat transfer member such that the second heat transfer member is arranged therebetween, and

the longitudinal direction of the second heat transfer member is along the direction in which the current flows in the first coil pattern.

10. The circuit device according to claim 1 , wherein

the printed circuit board includes the first coil pattern and at least one of the second coil pattern and a third coil pattern, the third coil pattern being inside the printed circuit board, the at least one of the second coil pattern and the third coil pattern surrounding the through portion of the core with half a turn or more,

the printed circuit board includes a thermal via, and

the thermal via connects the at least one of the second coil pattern and the third coil pattern to the first coil pattern.

11. The circuit device according to claim 10 , wherein the thermal via connects the at least one of the second coil pattern and the third coil pattern to the first portion of the first coil pattern.

12. The circuit device according to claim 10 , wherein

the first coil pattern includes a first extension portion at a position outside a current path of the first coil pattern, the first extension portion being a partially extended portion of the first coil pattern, and

the thermal via connects the at least one of the second coil pattern and the third coil pattern to the first extension portion of the first coil pattern.

13. The circuit device according to claim 12 , wherein

the at least one of the second coil pattern and the third coil pattern includes a second extension portion at a position outside a current path of the at least one of the second coil pattern and the third coil pattern, the second extension portion being a partially extended portion of the at least one of the second coil pattern and the third coil pattern, and

the thermal via connects the second extension portion of the at least one of the second coil pattern and the third coil pattern to the first extension portion of the first coil pattern.

14. The circuit device according to claim 5 , wherein

the printed circuit board includes the first coil pattern and a first thermal pad that is disposed on the first main surface and spaced away from the first coil pattern, and

the first thermal pad is thermally connected to the heat dissipator.

15. The circuit device according to claim 14 , wherein

the printed circuit board includes at least one of the second coil pattern and a third coil pattern, the third coil pattern being inside the printed circuit board, the at least one of the second coil pattern and the third coil pattern surrounding the through portion of the core with half a turn or more,

the printed circuit board includes a thermal via, and

the thermal via connects the at least one of the second coil pattern and the third coil pattern to the first thermal pad.

16. The circuit device according to claim 15 , wherein

the at least one of the second coil pattern and the third coil pattern includes a second extension portion at a position outside a current path of the at least one of the second coil pattern and the third coil pattern, the second extension portion being a partially extended portion of the at least one of the second coil pattern and the third coil pattern, and

the thermal via connects the second extension portion of the at least one of the second coil pattern and the third coil pattern to the first thermal pad.

17. The circuit device according to claim 1 , further comprising a third heat transfer member between the core and the first heat transfer member.

18. A power conversion device comprising:

the circuit device of claim 1 ; and

a switching element connected to the circuit device.