Cooling electronics with integrated heat carrier channels

The use of microelectronic components in harsh environments often requires the cooling of the components. One possibility to cool the printed circuit board (PCB) is integrating heat carrier channels into the board. These channels can be perfused with fluids such as oil or water and provide high heat convection rates while the thickness of the assembled circuit board is maintained at normal levels. Especially in applications , where the environment has higher temperatures than the electronics or where a small installation space is required, this technique provides a solution .

In this contribution we will explain the advantages of the proposed cooling system by the example of drilling equipment for deeply located natural resources. Employing the cooling technique will permit good performance of microelectronic components such as sensors or data processing units in the harsh environment of the Bottom Hole Assembly for monitoring, data logging and drilling control. Such PCBs is able to withstand high ambient temperatures up to 250 °C.

We have simulated, manufactured and are currently testing prototype boards with integrated heat carrier channels featuring a thickness of only 1.6 mm. As simulation scenario, we chose a board measuring 25 mm x 100 mm, dimensions suitable for integration into a BHA. An ambient temperature of 250 °C was used. The simulation results presented in this contribution illustrated that cooling of the whole board as well as cooling of hotspots is possible. The cooling channel layout being the key for high convection rates was meticulously studied and optimized. Parameters such as necessary flow rate and fluid pressure were adjusted accordingly.