Why Today’s Applications are Moving to 48V

February 1, 2018
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Designers of electronic systems are continually being tasked to increase the functionality of their products, whether it be more processing capability, higher data rates, increased torque or brighter LEDs. Delivering “more”, however, requires more power to be delivered.

Today, systems are increasingly constrained by size and/or weight restrictions, meaning the power system must deliver more power with the same or sometimes less weight and size. This is why a growing number of industries are moving to higher voltage, 48V distribution instead of conventional 12V distribution.

Why 48V?

I2R losses in a system can be detrimental to system efficiency and can reduce the power flow to the load effectively given cable, connector, and/or PCB limitations.

As an example, processor power in servers has increased from sub-100W to 200W, 300W, and even higher. Distributing this increased power to multiple server processors creates more losses unless mitigated by higher voltage distribution or larger copper bus bars if possible. Not just servers, but any design with increased power will have increased losses to the square of the current.

Higher voltage distribution of power reduces the I2R losses. For example, a 48V vs 12V power distribution scheme creates a 16X reduction in power loss.

Moving to higher voltage distribution has previously been associated with challenges that can actually lower overall efficiency, create a higher cost, and increase size/weight due to the converters required for the higher voltage. But these drawbacks in the converters are largely historical. Today, engineers can reduce I2R losses using higher voltage converters that enable efficiency, cost, and size/weight metrics comparable to or superior to those of lower voltage converters.

Telephony Started it All…

We can thank the development of the modern telephone and telephone exchanges for the earliest use of 48V. The communication industry standardized, and still uses, 48V to increase efficiency by reducing voltage drop over long cables (as a percentage of the operational voltage), allowing the use of smaller gauge wire and simplifying battery backup (also the reason for negative reference 48V) while still operating at a voltage level considered to be safe.

Where is 48V Being Used Today?

Today, it is widely documented that 48V is used in applications including data centers, automobiles, LED lighting, industrial equipment, and even power tools. It is impossible to go through a typical day and not see and use several 48V applications; 48V is the new 12V.

Globally, data centers and supercomputers consume power at the level of small countries and so efficiency is critical. With surging interest in artificial intelligence, computing solutions need processors that can keep pace with the increasing computational requirements. However, delivering higher processor performance presents physical challenges to power delivery, particularly with traditional 12V. Therefore, engineers have turned to 48V distribution to enable more efficient distribution of higher levels of power and overcome these challenges.

48V compared to conventional multiphase computing

48V Direct to PoL Conversion in Computing

One example of 48V usage is by Google. Google engineers openly discussed the merits and cost savings of 48V within their data centers at APEC2017 (Applied Power Electronics Conference, 2017) and OCP2017 (Open Compute Project, 2017). Another example of 48V adoption was highlighted at Supercomputing 2017, when the recent Green500 ranking was announced.

The Green500 ranks the most-efficient high performance computer systems. This year, four of the top five rankings were systems designed by PEZY, a Japanese company that deployed 48V distribution throughout their computer systems.

The size and power demands of enormous, outdoor LED screens have grown exponentially in the last decade. LED panels continue to increase in performance, delivering higher LED pixel density and brightness. Engineers designing these new panels are moving to 48V distribution, reducing the power cable size and weight while also increasing the efficiency. In addition to enhanced efficiency, these larger installations are benefiting from reduced weight and ease of installation. Today, smaller panels are assembled in a matrix to create a single brighter, longer lasting display that is also easier to transport and install. 48V power distribution also provides lower cost and a safer alternative to AC distribution schemes used in retail store wall displays and transportation-hub informational displays.

Consumer and professional battery-powered tools are following a similar trend, moving to higher voltages that allow more power to be delivered, enabling longer run times and higher torque for tools. Cordless tool batteries have progressed from ~9V to ~12V to ~18V to ~20V to ~24V, to now 48V and 60V. Walk into any home center and you will find a range of 60V battery tools and high performance 60V chainsaws and mowers from well-known companies.

Mild hybrids are increasing fuel efficiency by 10% or more in vehicles with a modest addition to existing combustion-based vehicles. Automotive engineers are using 48V power distribution schemes for mild hybrids to take some load off an internal-combustion engine by powering accessories during the “stop” phase of start/stop operation. Initial designs deployed a 12V only battery scheme, but the system couldn’t adequately power all the cabin features during the stop phase. 48V has proven to be the most efficient alternative.

Industrial equipment covers a wide range of products and 48V is being leveraged here for the same reason — more power. Applications range from robots for warehouses and process control to factory automation and ATE products.

48V is the New 12V

Increasingly, engineers are finding the losses associated with 12V distribution are limiting their systems. Moving to 48V is the best solution, with today’s 48V converters and regulators providing efficiency, cost, size and weight comparable to their 12V counterparts.
Many power designs are also capitalizing on the additional benefits of replacing intermediate stage regulators with a single regulator that converts directly from 48V to the load voltage instead of first regulating to 12V.

Moving to 48V is not difficult: in addition to our range of 48V DC-DC and isolated converters based on high-efficiency switching topologies, Vicor offers high-density power packaging and online tools that reduce design time and ensuring an optimized solution. If you need to deliver more power with higher efficiency then 48V really is the new 12V.

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