APEC 2024: Power to the data center

Data centers power the world, or does the world power data centers? According to one report, datacenters currently consume 2% of the world’s electricity and that could increase to 8% by 2030. Much of that electricity arrives at the load as low voltage, high current. For example, a single IC, processor, graphics processor, AI chip, or FPGA needs as much as 2000 A at 0.8 V. APEC 2024, a conference for power-electronics engineers, featured several demonstrations on this phenomenon.

Isn’t electrical power best delivered at high voltage, low current?

Well, yes. For example, the AC power delivered to your neighborhood arrives at thousands of volts. Transformers drop the voltage near the load, which increases the current but over a short distance. That minimizes losses caused by IR drops in the wires. Same for EVs. The batteries can produce hundreds of volts at low current whereupon load voltages are much lower.

The ICs in network equipment are, of course, digital and they can never be fast enough. That’s why logic levels continue to drop. Those 5 V TTL logic levels are too high for today’s high-speed digital devices. The difference between a logic 0 and logic 1 can go below 1 V, often 0.8 V. Why? Because it takes less time to switch between small logic levels.

Such a small difference in logic levels also creates signal-integrity issues. Digital receivers need lots of help distinguishing between logic states and at low voltages and must contend with noise. That brings in signal processing — predistortion and error correction — which also consumes energy.

The following videos highlight demonstrations related to data-center power.

Picotest

In the video below, Steve Sandler explains how Picotest uses a set of ten Analog Devices power modules to convert a 48 V power rail down to 0.8 V at 2000 A. That’s what it takes to power today’s devices. Engineers can use this board to test power rails while the ASIC, emulated by the board, is in development. The board lets engineers control load current from 0 A to 2047 A with 1 A resolution.

STMicroelectronics

Delivering power to a data center encompasses more that just delivering high-current, low voltage power on a board. At APEC 2024 ST’s David Bates demonstrated the company’s offerings.

The ecosystem starts at 48 V, after which regulators bring the voltage down to 12 V. Following that, protection devices keep the main board safe. Each e-fuse can handle up to 60 A or 120 W. The e-fuses are resettable MOSFETs. The final stage drops the voltage to load levels, which can be as low as 0.8 V. That occurs close to the load to minimize IR drops on the board. Bates also explains the concept of phases in DC power delivery.

Texas Instruments

In the Texas Instruments booth, Abhinay Patil demonstrated a power-delivery reference design for servers. The demonstration started with a 12 V power supply. The reference design provides input protection, temperature protection, and short-circuit protection using TPS25990 e-fuses. DC-DC converters drop the voltage to 1.8 V. The board can deliver up to 700 A.