Dual output high efficiency power supply

I needed a dual output power supply that could power a hard-drive. I later realized that today’s newer hard-drives use a single supply of 5V. However by that time I had already designed this one. So I thought I’d build it. There are several such supplies available on eBay and such. However they are unsafe for an HDD as they use cheap voltage regulators such as the 7805 and 7812. Also they are not efficient at all. The 78XX series has an average efficiency of around 40% which is disastrous and the power wasted would be a little too much (especially if the source is a battery).

Here is a design based on TI’s TPS54383 dual regulator. This one has an efficiency of more than 90% at full load of 3A. The chip also features an over-current limit protection. An over-voltage protection can also be implemented externally. The output voltages are fully configurable. I made another version which has 5V and 3.3V outputs. The component values for these standard voltages are in the schematic.

This supply’s outputs can also be controlled independently through a micrcontroller/microprocessor without any additional circuitry through the EN1 and EN2 ports. These ports recognize TTL logic levels. A logic low enables the supply while a logic high disables it.