Patent Publication Number: US-2023134163-A1

Title: Printed circuit board assembly

Description:
The invention relates to a printed circuit board assembly having a printed circuit board that has at least one conductive inner layer and, on at least one surface, contact areas and electrical and/or electronic components that are electrically connected to the contact areas. 
     A printed circuit board assembly of this type is known from DE 10 2007 051 316 7 A1. The inner layers of these known printed circuit boards have a thickness of about 35 μm for the power supply and signal routing of conventional electronic components, and the insulating intermediate layers also have thicknesses that meet the insulation requirements of not excessively high voltages. 
     However, if use is made of power electronic components that have to switch voltages of 400 V to 800 V or higher at currents of several 100 A, the lines to and from these power electronic components must also be dimensioned accordingly. This means that both the electrically conductive inner layers and the insulating intermediate layers must be made to be significantly thicker. However, this makes the entire printed circuit board significantly thicker and also considerably more expensive. 
     It is therefore the object of the invention to find a solution for a printed circuit board assembly with high-voltage and/or high-current components. 
     The object is achieved by a printed circuit board assembly that is formed with a printed circuit board that has at least one conductive inner layer and, on at least one surface, contact areas and electrical and/or electronic components that are electrically connected to the contact areas, wherein, according to the invention, at least two of the contact areas are connected to one another via an electrically conductive strip, the ends of which are connected to each one of the contact areas, and wherein the at least two contact areas and the electrically conductive strip have a width of at least 8 mm and the strip has a thickness that is at least twice the thickness of the at least one inner layer. 
     Connections that have to carry large currents or to which high voltages are applied are therefore produced by means of additional, electrically conductive strips, for example metal strips. These strips are, for example, welded to the corresponding contact areas, which must be designed to be sufficiently large and thick. Conventional bonding techniques can be used for this. 
     These electrically conductive strips can be adapted very variably to the respective circumstances. They can therefore be selected according to the requirements in terms of their dimensions and in terms of the material used. 
     The invention is intended to be explained in more detail below on the basis of an exemplary embodiment with the aid of figures, in which: 
    
    
     
         FIG.  1    shows a cross section through a printed circuit board assembly and 
         FIG.  2    shows a plan view of a printed circuit board assembly. 
     
    
    
       FIGS.  1  and  2    show a printed circuit board assembly  1  in a cross section and a plan view having a printed circuit board  2  that is formed from a sequence of at least partially conductive layers as inner layers  4  and insulating layers  9  arranged between the inner layers  4  and pressed to them. Such printed circuit boards are known, with the conductive and insulating layers usually having a thickness of about 35 μm. 
     In the exemplary embodiment shown, an insulating layer  9  is implemented on a surface  3  of the printed circuit board  2 , in which contact areas  5  are embedded. The contact areas  5  can also protrude from the insulating layer  9  or be formed on it. They can be connected to other conductive structures by means of conductor tracks (not shown) also arranged on the surface  3  of the printed circuit board  2  formed as an insulating layer  9 , or they can also be connected to inner, conductive layers (inner layers  4 ) by means of vias. 
     As examples, electrical or electronic components  6 ,  7  are arranged on the contact areas and are electrically connected to them in order to supply them with energy, for example. The components may be, for example, power semiconductors for switching high currents in the range of a few hundred amperes. 
     Since such high currents require conductors with correspondingly high cross-sections or thicknesses, the layer thicknesses of around 35 μm usually used for printed circuit boards are not sufficient; on the one hand, therefore, conductive layers would have to be realized with a greater thickness, but on the other hand, insulating layers would also have to be made correspondingly thicker. This would increase costs significantly. 
     For this reason, electrical connections that have to carry higher currents are implemented according to the invention with a conductive strip  8  that is at least 8 mm wide and has a thickness at least twice as thick as the thickness of the at least one inner layer  4 . Such a printed circuit board assembly has the advantage that the electrically conductive connection between two contact areas  5  can be easily adapted to the respective requirements in terms of current carrying capacity, without the entire printed circuit board design having to be changed. Conventional printed circuit boards  2  can thus also continue to be used for large currents.