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JANUARY 2022 I DESIGN007 MAGAZINE 47 voltage and may convert it to moderate voltage at high current. As such, some sections of the PCB may need to be designed to withstand the heat generated by high current. ere are two important tasks in high-cur- rent design that help ensure reliability: • Trace width sizing: Traces in a high- current PCB need to be made wide enough to prevent high temperature rise. ese requirements and a useful nomograph are specified in the IPC 2152 standards. • Heat dissipation: When heat is generated in a high-current PCB, the heat needs to be moved away from components to prevent them from exceeding their temperature rating. e heat generated in these boards can be removed with plane layers, fans, heat sinks, or by using a high thermal conductivity substrate with a metal housing. When high-current PCB design rules are used with the clearances defined for high-voltage PCB designs, a designer can rest assured their board will be safe and will provide high current without excessive temperature rise. Managing Heat in Your High Voltage PCB Design Fans, heat sinks, exotic materials, and even liquid cooling can all be used to remove heat from a high voltage/high current PCB. How- ever, a designer needs to determine the maxi- mum temperature rise they can tolerate in the board to ensure reliability. Once this is deter- mined, the trace width and other required heat dissipation measures can be determined. Once high voltage and high current design rules for your circuit board are determined, the best design soware will check your PCB layout against these rules automatically. • Once you've determined the allowed temperature rise in your PCB, you can use the IPC-2152 guidelines to determine the minimum trace width you need. • Just like other modern PCBs, high current traces may need to be routed through a via and onto an interior layer. Figure 2: PDN simulations can help you identify areas where current is too high.