Higher Distribution Voltage for Server Efficiency Increase

Several years ago Google suggested an open standard for desktop PC power supplies with a single 12V rail instead of multiple rails. The point was the higher buss voltage the higher overall PC PSU efficiency.

This year Google power designers are going to present at DesignCon 2013 their strategies for reducing energy losses in servers, including DC-DC regulator architectures as well as higher voltage distribution. Google apparently is going to make a case that higher distribution voltage levels improve overall conversion efficiency. Obviously, raising the buss voltage will lower conduction losses. On the other hand, switching losses in downstream DC-DC regulators will increase. In addition to this, you will need to use higher voltage MOSFETs whose characteristics generally degrade with their rated voltage. That's why it will be interesting to see their experimental results and  conclusions on optimal distribution level.