What exactly does the reference design include?

I have a 10 month old daughter. As many of you with kids know, bedtime can be a little tricky. I sometimes find myself watching infomercials late into the night. I've watched so many that I can almost predict what's going to happen. My favorites include "Wait! There's more!" and "If you call now, we'll double your gift!" I never bought anything (unless I saw it in a store a few months later), but the ideas are great and usually entertaining.

PowerLab notebooks have been around for about six months, and  the PowerLab  itself is over a year old, but I haven't yet described what a typical PowerLab design actually consists of, nor explained why. I thought it would be time to explain it, and in the style of an infomercial. Perhaps you'll be tempted to give it a try, "after all, it's free!"

Each design included in PowerLab starts with a set of performance specifications from real applications. These performance specifications are provided by engineers looking for the right power solution for their system. Once we have these performance specifications, we start selecting the best TI part for the job.

From this point on, the first piece of art generated is the schematic . The schematic is the first and most important piece of art developed because everything is based on it. Typically, we share the schematic with the customer and go back and forth to make sure all specifications are met. It is easy to make changes at this point, but it becomes more difficult later.

 Example schematic diagram of PMP7390 :

During the schematic design process, the selection of specific parts is critical. You must ensure that the part you choose is the best choice for the job and is currently available. Parts may become obsolete or not recommended for new designs. Once all parts have been identified, a Bill of Materials  (BOM) can be generated . The BOM is provided with every PowerLab design.

Example BOM:

Now that we have a schematic and BOM, the next step is Printed Circuit Board  (PCB) layout . This step creates the artwork necessary for the physical board generation. PCB layout is critical to the design of a power supply and can determine if it will work. All PowerLab designs include layout guidelines, PCB images, and many also include the actual PCB design files as well as Gerber files (necessary to build the PCB). All the information needed to build the power supply is included.

Example of a circuit board image of the PMP7390  :

"Wait, there's more!"

All reference designs in PowerLab are fully tested, which means that each reference design includes a comprehensive test report , including but not limited to the following:

1. Power-on waveform
2. Output voltage ripple
3. Transient response (load step response)
4. efficiency
5. Load Regulation
6. Switching Waveform
7. Thermal imaging

 Test data example of PMP7390 :

I (or another design engineer) then captured and verified all the test data. TI engineer Bob Hanrahan created a 4-part design-in-a-box video on how to test power supplies, focusing on measuring efficiency , measuring stability , and measuring noise . You can watch the overview below, or click on the links above to learn more about specific tests.

In summary, if you choose a  PowerLab  reference design, you get:

1. Schematic
2. BOM
3. PCB Layout
4. Test Report