that at least one electronic component is buried in the gel like resin the gel like resin coated in the recessed portion is such an amount that a gap between the electronic component and side surfaces and bottom surface of the recessed portion is filled with the gel like resin and an excess amount of the gel like resin is expelled out of the side surface of the heat dissipation board the gel like resin protruded from the side surfaces of the heat dissipation board is removed application_number US 36839903 A description a preferred embodiment of the invention will be described with reference to the accompanying drawings fig2 a to 2 d show a whole structure of an electronic circuit board assembly according to the embodiment of the present invention in which fig2 a is a plan view fig2 b is a bottom view fig2 c is a front view and fig2 d is a right side view of fig2 a in the following description a switching power source will be taken as a desirable example for applying the heat dissipation structure according to the present invention the switching power source includes dc u2014 dc converter for converting a dc voltage to another dc voltage having a different level because power loss yields.