Power-Supply Design: How Hard Could It Be? (.PDF Download)

Sept. 4, 2018
Power-Supply Design: How Hard Could It Be? (.PDF Download)

At some point in your engineering career, you will probably have to design a power supply. Every electronic product or system needs one. The first two decisions to make when addressing your power-supply requirements are:

  1. Do you make the supply yourself or buy it?
  2. Do you use a linear or switching supply?

If you only need one or a few supplies, it generally doesn’t pay to design and build them yourself. Plenty of commercial supplies are available for all but specialized demands. On the other hand, for high-volume needs, designing your own makes more sense—it will be less expensive in the long run.

As for the linear vs. switching decision, go with a linear supply if you’re not so concerned about efficiency. They are simple and inexpensive. Choose a linear supply if your supply must not generate electromagnetic interference (EMI). Linears are quiet and clean. Furthermore, you may be able to use a low-dropout (LDO) linear regulator that’s not only quiet, but also provides good efficiency for a linear.

Most new supply designs today are switchers. They offer exceptional efficiency and are usually smaller and lighter than most linear supplies. Such supplies are complex; unless you’ve had some experience with them, you will probably need help. That’s the goal of power-supply design software. These useful software tools let you enter the desired specs and will deliver a complete design. An example of one such software design tool is Texas Instruments’ WEBENCH.

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