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:
- Do you make the supply yourself or buy it?
- 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.