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Power Supply PCB Design Guidelines for Manufacturing 

When talking about power, the priority is usually to get more of it. As teenagers, we wanted the most powerful cars, cities always need more electrical power for their populations, armies need more military power, and the space race pushed the limits on building more powerful rockets. Printed circuit boards also need more power, but their priorities are a little different. The goal of a successful PCB design is to provide it with clean power.

The power supply you create on your PCB design needs to provide the rest of the circuitry with clean, uninterrupted power. You need to design the power supply so that it creates as little noise as possible, and the noise that it does create will be isolated from the rest of the design. You also must consider how the heat that the power supply will create will affect the circuit board, and design for it accordingly. Lastly, you also need to understand how your design will affect the manufacturing process of the board. Here are some power supply PCB design guidelines that can help.

PCB Design Considerations for Power Supply

Whatever the purpose of your printed circuit board is, it will need power to function. Typically, this is accomplished with an onboard power supply. Power supplies are broken up into two main groups according to their operation:

  • Linear power supplies are fairly simple and low cost to design onto a PCB. They are used in systems where the power requirements are lower.
  • Switch-mode power supplies (SMPS), on the other hand, are more efficient than linear power supplies, but they are also more complex and their switching noise can create EMI if care isn’t taken in their design.

SMPSs are further divided by type: isolated and non-isolated. Higher-input voltages require the use of transformer isolation. There are many isolated SMPS variations, depending on their function and power rating, including flyback, forward, push-pull, half bridge, and full bridge. Non-isolated SMPSs include the following types:

  • Buck: This SMPS steps down the voltage while stepping up the current.
  • Boost: This SMPS steps up the voltage while stepping down the current.
  • Buck-boost: This SMPS contains elements of both the buck and boost converters, and will either step down or step up the output voltage.

Whichever power supply type and configuration you end up using on your board, it must be designed to deliver clean power with as little noise as possible. To that end, there are some considerations that you should keep in mind when designing the power supply on your PCB:

  • Current: Your power supply will be dealing with high levels of current, so make sure that you use adequate trace widths and copper weight to handle it.
  • Noise: You should use the most compact packages possible, the tightest and most optimized component placement, the best grounding strategy, and the shortest routing to reduce the chance of noise creating EMI for the rest of the board.
  • Heat: A power supply will get hot, so make sure that you design your supply to dissipate heat as much as possible.