Hi Kevin,
For your condition, with the limited input information, here are two comments:
1. The efficiency can be lower when the output power is lower. With 5-W output it's possible for you to see a lower efficiency compared to 15-W output.
2. The…
Part Number: TPS65988DK Other Parts Discussed in Thread: TPS2546 , TPS2547 , TPS2514A , TPS65987DDK I'm working on a new USB charging product to be installed on airplanes. I understand the power requirements well enough: it has to take 12V-32V input and…