Above: IBM’s Blue Gene computer paved the way for powerful AI Data Centers
“The large data centers are undergoing a deep structural change. We anticipate more datacenters moving away from Alternating Current (AC) in favor of 260-410V DC infrastructures to better cope with the massive increases in power needs of high-performance computing,” told Lev Slutskiy, Vicor’s EMEA Business Development Manager for High Performance Computing. “Google started testing the concept secretly back in 2015 and today companies like Nvidia are performing experiments with high voltage, that haven’t been published yet.”
According to Slutskiy, the Open Compute Project Foundation is also testing the new approach. The OCP was established 10 years ago by Facebook and now it brings together the biggest manufactureres of processors, servers and data center infrastructures. They are tackling an old electrical dilemma: Since the electric power is a multiplication of the voltage by current, using a high direct voltage at low currents saves a lot of energy (P = I²R). Until recently the problem was marginal: standard database servers consumed approximately 5kW each – and power systems that passed energy into the server circuits at a voltage of 12V and 416 Amps current – were good enough.
What can be done with 1,000 Amps
But times change and around 2015 the average power consumption of database servers increased to 12kW, with currents ranging up to 1k Amps. Most of the manufacturers dealt with the high currents using very large conduction cables, but this solution is beginning to reach the end of its ability. Especially in the last year in which the growing use of artificial intelligence and machine learning multiplied the power usage of the database servers: Vicor reports that in the large data centers the usage increased to about 20kW, and in some cases even to 100kW.
This means that the power distribution systems need to deal with huge currents of appoximately 1k Amps. At this point the OCP consortium started to define a format of database servers working at higher voltages of 48V. This decreases the current in the circuit by 4 and minimizes the power loss in the conduction cables by 16. Thus for instance, the current required for 12kW server will be only 250 Amps.
According to Jain Ajithkumar, Vicor’s Sr. Director for Strategic Accounts in Data Center, HPC and AI Business, this is just the first move in a larger trend and it holds further technological implications. “We are now at the beginning of a new era. The computer rooms will receive direct voltage of 350V, that will be converted to 48V at the racks level, and then to the exact voltage needed by each specific chip in the server.
“We are dealing here with two additional issues: today the processors work at 1.8V and 0.8V. When we minimize the width of the transistor to 5 nanometers, the voltage may reach down to 0.4V. There is a need for an advanced technology to answer this need – and to do it without compromising the space dedicated to the multitude of densed data links populating modern processors.”
Looking for the next Startup
This is where Vicor’s Factorized Power Architecture technology, originally developed for IBM’s 2007 Blue Gene supercomputer, comes into the picture. Blue Gene was powered by 350V, delivered through Vicor’s power distribution system, starting with high power rails, middle stages and ending with a dedicated chip directly connected to the CPU’s power connections. “We have developed a technique for pushing the power supply to each processor of Blue Gene.
“Now we are making that technology available for startup companies too, and therefore it is very important for us to exist in the Israeli Market. Out of all the influential startup companies in the world, just 5% come from Europe. Thus Israel’s foothold in the European market is very large. Today there are over 300 HPC startup companies in Israel, and most of the startups that are being sold to global companies are Israeli. We are offering to supply them with chips and full planning methodologies – including converting supply networks to voltages of hundreds of volts, bringing energy to the consumption point, lowering to a voltage of 48 volts and supply the required voltage for each processor.”