3.2kW GaN reference design for data centre AI power ...

Nov 29, 2023

The CRPS185 3 Titanium Plus server reference design from Navitas surpasses the stringent 80Plus Titanium efficiency requirements to meet the increasing power demands of AI data centre power.

Power-hungry AI processors like Nvidia’s DGX GH200 ‘Grace Hopper’ demand up to 1,600 W each, are driving power-per-rack specifications from 30-40 kW up to 100 kW per cabinet. Meanwhile, with the global focus on energy conservation and emission reduction, as well as the latest European regulations, server power supplies must exceed the 80Plus ‘Titanium’ efficiency specification.

The Navitas reference designs reduces development time and enables higher energy efficiency, power density and system cost using GaNFast power ICs. These system platforms include complete design collateral with fully-tested hardware, embedded software, schematics, bill-of-materials, layout, simulation and hardware test results.

The CRPS185 uses the latest circuit designs including an interleaved CCM totem-pole PFC with full-bridge LLC. The critical components are Navitas’ new 650V GaNFast power ICs, with robust, high-speed integrated GaN drive to address the sensitivity and fragility issues associated with discrete GaN chips.

The GaNFast power ICs also offer extremely low switching losses, with a transient-voltage capability up to 800 V, and other high-speed advantages such as low gate charge (Qg), output capacitance (COSS) and no reverse-recovery loss (Qrr). As high-speed switching reduces the size, weight and cost of passive components in a power supply, Navitas estimates that GaNFast power ICs save 5% of the LLC-stage system material cost, plus $64 per power supply in electricity over 3 years.

The design uses the ‘Common Redundant Power Supply’ (CRPS) form-factor specification defined by the hyperscale Open Compute Project, including Facebook, Intel, Google, Microsoft, and Dell.

Using CPRS, the CRPS185 platform delivers a full 3,200 W of power in only 1U (40 mm) x 73.5mm x 185 mm (544 cc), achieving 5.9 W/cc, or almost 100 W/in3 power density. This is a 40% size reduction vs, the equivalent legacy silicon approach and easily exceeds the Titanium efficiency standard, reaching over 96.5% at 30% load, and over 96% stretching from 20% to 60% load.

Compared to traditional ‘Titanium’ solutions, the Navitas CRPS185 3,200 W ‘Titanium Plus’ design running at a typical 30% load can reduce electricity consumption by 757 kWh, and decrease carbon dioxide emissions by 755 kg over 3 years. This reduction is equivalent to saving 303 kg of coal. Not only does it help data centre clients achieve cost savings and efficiency improvements, but it also contributes to the environmental goals of energy conservation and emission reduction.

In addition to data centre servers, the reference design can be used in applications such as switch/router power supplies, communications, and other computing applications.

“The popularity of AI applications like ChatGPT is just the beginning. As data centre rack power increases by 2x-3x, up to 100 kW, delivering more power in a smaller space is key,” said Charles Zha, VP and GM of Navitas China.

“We invite power designers and system architects to partner with Navitas and discover how a complete roadmap of high efficiency, high power density designs can cost-effectively, and sustainably accelerate their AI server upgrades.”

navitassemi.com