Reducing waste power, cooling, and space aren't just data-center-size concerns; they're also battles fought inside the confines of each rack. And, sometimes, even one small change can make a big difference.
For example, power coming into a rack at 48 volts needs to be stepped down to 1V. The traditional power supply circuitry needs to do this in two stages: from 48V to 12V, and then from 12V to 1V. That's typically only about 79% efficient. The two-stage power supply eats up a bunch of precious space, plus you need empty space for cooling to remove waste heat from the conversion process.
Enter Gallium Nitride (GaN) integrated circuits (IC). According to Alex Lidow, CEO of Efficient Power Conversion (EPC), his company partnered with Texas Instruments (TI) to create a GaN-based power supply design. Using the design, he says, "Transistors using GaN instead of silicon can go directly from 48V to 1V, in one step. And using GaN on a server motherboard can potentially reduce power losses from power conversion within the rack by 50%. We are seeing efficiencies of 91% in power conversion, and overall power savings of about 15% of the total power consumption of the server farm, going from 66% system efficiency to 76%," he says.
However, GaN-based power ICs aren't something that can be retrofitted to existing gear: You'll need new motherboards. These power supplies will need new controllers and drivers, which companies such as TI have been busy creating, said Steve Tom, director of High Voltage Technology at TI. And they'll need GaN-savvy engineers. "We've written textbooks used in over 100 universities, we have graduate programs in over 100 universities, we're starting to see PhDs with experience in GaN," says EPC's Lidow.
Companies that build their own servers from scratch, making it easy to move to GaN-based power supplies—e.g., Google Open Architecture, Facebook, and Amazon—are early GaN adopters; expect this to show up in mainstream vendors over the next three to five years, using EPC's or other companies' GaN processes.
