“Nowadays there is some dislocation between power demand and infrastructure. Computing power such as data centers and electric vehicles has grown significantly in the past few years, which has brought great demand for power consumption, but the power transmission bus is still All are stuck on the 12V standard created in the past few years, and upgrading to the 48V system will become an important solution to solve the needs of the terminal.” A few days ago, Vicor marketing manager Meng Lingchong told the media when attending the OCP conference a few days ago, this OCP conference On the previous page, Vicor, as the only board-level power module/chip supplier, discussed the 48V DC power supply system for data centers.
Will power density and efficiency continue to grow?
With the emergence and development of MOSFET technology, power conversion efficiency has been greatly improved in the past thirty years. When the 80PLUS standard took effect in 2007, the highest half-load efficiency requirement has reached 96% when upgrading from gold to platinum and today’s titanium.
The efficiency and density of the power supply are strictly positively correlated. The higher the efficiency, the less heat dissipation. Therefore, smaller size, smaller power loss, and cheaper and simpler heat dissipation system can be achieved, which promotes the development of a green and energy-saving information industry.
According to the product roadmap given by Vicor, between 2012 and 2019, the power density increased from 0.8 kW/cubic inch to 10 kW/cubic inch, and the current density at the point of load increased from 0.8A to 2A. From a longer-term point of view, between 1984 and 2021, the power density has increased by as much as 500 times.
However, as the performance of MOSFETs is close to the limit, power supply manufacturers have begun to try various innovations in order to meet the continuously increasing demands of power, efficiency and density. Including the use of wide bandgap devices such as GaN and SiC, updated topological junctions, etc., but Vicor has always adhered to traditional silicon so far. Phil Davies, the company’s vice president of sales and marketing, once said in an interview: “I often get asked about the company When will GaN technology be used, but we do not need them. Because low-voltage MOSFETs are cheaper and have higher quality factors, and we have achieved 800V input with a unique topology. So we do not need to use expensive , GaN without extensive verification.”
On the one hand, Vicor continues to strive for perfection and upgrades its products. On the other hand, it provides system-level innovation around the 48V system, so as to more fully meet the upgrade of today’s advanced systems.
In any case, just as Moore’s Law is still advancing steadily despite its difficulties, power technology is still constantly using various methods to advance to meet the development of Moore’s Law.
For big data centers, Vicor’s 48V solution
Almost all the electricity consumed by the big data center is converted from alternating current. Data centers generally have a complete set of complex current transmission paths, from AC to DC, and then further conversion to power memory, peripherals, processors and other components.
With the rapid increase in the amount of data such as videos and pictures, the current data center can no longer rely on pure CPUs, but has evolved into heterogeneous processing including GPUs, FPGAs, and AI processors. At the same time, the power consumption of the processors using advanced processes is getting higher and higher, the core voltage is getting lower and lower, and the current is getting higher and higher. According to the formula P=I?R, the loss on the power bus will become larger and larger. This is also an important reason why companies including OCP members Google and Facebook have upgraded their internal power bus to 48V.
The calculation results given by Vicor show that if the entire system is converted to 48V, the efficiency will increase by 30%.
In view of the characteristics of the current market, Vicor has introduced three major solutions including AC/DC, 12V/48V bridging and point of load. The company’s engineer Yang Zhou gave specific interpretations.
Solve the last inch of power supply
First of all, for the point of load, Vicor provides a variety of solutions, including split power architecture, horizontal power supply (LPD) and vertical power supply (VPD).
The fractional power supply architecture decomposes the power supply into specialized voltage stabilization and voltage transformation functions. These two functions can be optimized and deployed separately to provide a high-density and high-efficiency solution. This solution is different from the traditional 12V multi-phase solution, which mainly relies on a parallel array of switching regulators and inductors. This traditional solution is aimed at high-power applications. The more parallel regulators, the larger the overall size and the larger the processor. The longer the distance of current transmission. All of these will cause more losses in the system.
“After separating the two parts, the second stage can realize a smaller and thinner fixed ratio converter without the need to design a complicated voltage regulator function, which is more suitable for the compact space requirements around the CPU.” Yang Zhou said.
The horizontal power supply of the sealed power supply refers to the second-level power supply module of the split ratio, which can be directly arranged close to the processor or even directly on the processor substrate, which can not only minimize the wiring harness loss, but also reduce the power supply. The required processor substrate BGA pins. Yang Zhou said: “Traditionally, converters require inductors for power supply. However, due to electromagnetic interference, the Inductor cannot be too close to the CPU. This makes the last inch still have a large loss, especially when the current exceeds 1000A in the future. The LPD solution is It can solve the last-inch power supply problem.” At present, LPD has been widely used in OCP accelerator module (OAM) cards and custom AI accelerator cards. According to the data provided by Davies, “In 48V AI system applications, Vicor occupies 85 % Market share.”
According to public information, domestic and foreign companies including NVIDIA, Intel, Cambrian, Tianshu Zhixin, Google and other domestic and foreign companies have adopted Vicor’s solution. (The yellow strip product in the picture below is Vicor’s power supply module)
The VPD solution is a power supply solution closer to the CPU. For example, Cerebras, which uses a wafer-level engine (WSE) to form a whole processor with 84 processing units, can significantly reduce the transmission delay associated with the traditional socket-type single-signal chip architecture. But first, the power of WSE is as high as 15kW, and second, the chip area is too large, and the traditional power supply scheme cannot supply power for each unit at the same time. Therefore, Cerebras cooperated with Vicor to implement the VPD solution, placing the power converter under the substrate, facing the position of the processor power IO, to achieve the highest density power supply system.
Yang Zhou especially emphasized that Vicor provides many product combinations, including integrated primary and secondary split power modules, as well as discrete solutions, and realizes the Pin 2 Pin compatibility of secondary modules, which can facilitate customers according to the actual processor Power consumption can be adjusted at any time.
Solve bidirectional bridge connection from 12V to 48V
48V has many advantages, but more than 90% of traditional data center architectures are still powered by 12V, but the accelerator card, OCP accelerator module, AI server, etc. have been upgraded to a 48V system.
In order to achieve a 12V and 48V hybrid solution, Vicor has introduced a 12V to 48V bidirectional conversion solution. This scheme can automatically realize the two-way conversion from 12V to 48V without any modification to the periphery, and achieves a conversion efficiency of more than 98%. Not only requires minimal external components, but also can be easily connected in parallel to obtain higher power levels. Vicor’s bridging solution brings greater flexibility to customers. When they are dealing with the transition to 48V power distribution, they can give full play to the advantages of the new generation of AI cards. The recent two-way 48V/12V converters have added an extra layer of flexibility to cloud data center providers: as the infrastructure develops, it can support either one of these standards or both.
Davis said in a previous conference call: “Intel and AMD are using their CPUs in 48V data centers. Among them, there will be huge demand for bridge chips. After five years, the total market capacity will reach 500 million US dollars. As far as Intel and AMD are concerned in ultra-large-scale data center applications, artificial intelligence still dominates the demand for bridge chips.”
Solve high-voltage DC/DC and AC/DC conversion
The power supply market for rack-mounted servers is also facing the challenge of a surge in power density. “Before 2015, the power growth of rack-mounted servers was not significant. However, with the rapid increase in power, there has been an explosive increase in rack power density. In 2020, the power of a rack may reach 200kW or more. According to the previous The calculation of power density may require dozens of times as much space, which poses a huge challenge to the power supply system.”
“The traditional silver box-based power density increase is too slow, and Vicor wants to break this tradition.” Yang Zhou said. Vicor provides two solutions for primary power supply, one is a high-voltage DC power supply module, which supports the conversion of 400V/800V to 48V. The other is an AC to DC module, which is only the size of an iPad (92 mm × 80 mm × 7.5 mm), but it can achieve 5kW power output and supports parallel connection. Due to its small size, it can be laid out flexibly, including on the side and back of the rack or even in the liquid-cooled power supply box. In addition, Yang Zhou also said that the current data center is still using traditional 220V power supply, but in order to achieve higher power density, it should switch to a three-phase 380V power supply system.
More than ten years ago, Vicor began to develop and promote the 48V system, and has invested hundreds of millions of dollars. Today, remarkable results have been achieved. “During the development of 48V, in addition to clear data centers, we have seen automobiles, industries, robots, drones, rail transit, ATE equipment, and LEDs all begin to get involved in 48V applications,” Meng Lingchong said.
According to Vicor’s recent financial report for the second quarter of 2021, the revenue of the Advanced Products product line, which mainly includes 48V, has accounted for 43% of the company’s total revenue. This business revenue has increased by 20% from the previous quarter, which is why Vicor’s second quarter The overall revenue achieved a chain growth of 7.4% to 95.4 million U.S. dollars.
Vicor’s long-term goal is that Advanced Products’ product revenue will account for 80%, and the traditional brick power supply business will shrink to 20%. “In 2026, Advanced Products’ target market capacity will reach 20 billion US dollars.” Davis said in the earnings conference.
It is precisely because of this that Vicor is expanding a new factory to increase the area of 8,500 square feet, which is expected to meet the annual output value of 750 million US dollars. In addition, Vicor is also looking for opportunities to set up new factories, and finally achieve an annual output value of 1.5 billion US dollars.
Chen Xinjun, Sales Director of Vicor China and Head of Data Center and Supercomputing, said: “Vicor is a company that pursues the ultimate. In order to achieve small and beautiful products, we continue to improve packaging, materials, and control technologies to achieve higher efficiency and power. Density. At the same time, we are also simplifying and standardizing power applications so that AI companies can pay more attention to the performance of the chip itself.”
“The world is undergoing rapid changes. When we began to shift from niche traditional markets such as military, aerospace, and defense to fast-growing emerging markets such as automobiles and data centers, our competitors are also changing. Traditional power suppliers have become more semiconductor companies.” Davis said. “We must also make some changes.”
At the 2021 shareholders meeting, Vicor proposed a new five-tier growth strategy, including existing customers, new customers, high-growth markets, innovative products and technologies, and clearer brand information. Most of these, All will be carried out around the 48V architecture.