Patent ID: 9555828
Date: 2017-01-31
CPC Classifications: B62D,H05K

Claim:
1. An electronic control unit for controlling a control target, the electronic control unit comprising: a board having a first surface and a second surface opposite to the first surface; a power Zener diode that is mounted on the first surface of the board; a plurality of high-heat-generating devices, wherein: a controller that controls the control target by controlling at least one of the plurality of high-heat-generating devices; a heat-dissipating member located facing the first surface of the board; and a heat-conducting member located between the first surface of the board and the heat-dissipating member, wherein: the first surface and the second surface include a first limited region and a second limited region, respectively, which are opposed to each other in a direction perpendicular to a plane of the board and are placed in an extent of the heat-conducting member in the plane of the board; the switching device mounted on the first surface is located in the extent of the heat-conducting member in the plane of the board in the first limited region to transfer the heat of the switching device mounted on the first surface to the heat-dissipating member through the heat-conducting member; the second high-heat-generating device mounted on the second surface is located in the extent of the heat-conducting member in the plane of the board in the second limited region to transfer the heat of the second high-heat-generating device mounted on the second surface to the heat-dissipating member through the board and the heat-conducting member; the power Zener diode is arranged near the switching device in the first limited region to serve as a heat mass; when a power, which is supplied from a power source to the electronic control unit, is larger than a threshold, the power Zener diode enables an electric current to flow from the power source to a ground through the power Zener diode to limit conduction of the electric current from the power source to the electronic control unit; and when the power, which is supplied from the power source to the electronic control unit, is not larger than the threshold, the power Zener diode prevents the electric current from flowing from the power source to the ground through the power Zener diode to enable conduction of the electric current from the power source to the electronic control unit and absorb some of the heat generated from the switching device.