Vicor proposes factorised power modules to meet Google power thinking
Embodying advances in power conversion engines, control systems and modular power technology, these 48V modules are being introduced following the Open Compute Project (“OCP”) Summit 2016 at which Google announced its initiative to promote 48V server and distribution infrastructure as a standard for data centres. Patrizio Vinciarelli, President and CEO of Vicor, commented: “By developing its 48V server infrastructure, Google pioneered green data centres. And by promoting an open 48V rack standard, Google is now enabling a reduction in the global cloud electricity footprint.”
Although the benefits of a higher distribution bus voltage, particularly 48V, which requires no special safety precautions, are well known, Vicor says, (smaller cables and bus bars, lower distribution losses, smaller storage capacitors), conventional power conversion approaches have not been able to efficiently, or compactly, transform power from a 48V bus into the low voltages (e.g., 3.3V, 1.8V and 0.8V) and high currents (e.g. 95 Amps) required by contemporary CPUs or GPUs. As a result, CPU power conversion has customarily relied on 12V distribution. A 12V bus, however, must carry four times the current carried by a 48V bus, and, because distribution losses are a function of the square of the current, the power lost in a 12V bus can be as much as 16 times the loss in a 48V bus. By providing efficiencies from a 48V bus that are better than 12V legacy solutions, in a fraction of the space, Vicor’s 48V Direct-to-PoL product families enable system designers to implement “green” distributed system solutions featuring high conversion efficiency, high power density and low distribution loss.
Vicor’s latest generation 48V Direct-to-PoL modules include the Cool-Power PI3751-02 Buck-Boost, Pre-Regulator Module (“PRM”) and the VTM48Kp020x Current Multiplier Module (“VTM”). The PRM receives its input from a 48V distributed bus (Vin up to 55V) and drives a controlled “factorised” bus voltage to the VTM; the VTM generates an output voltage that is 1/24th of the voltage at its input while multiplying by 24X the current delivered to the CPU. Current multiplication by as much as 48X at the Point-of-Load delivers higher efficiency, density and bandwidth, distinguishing attributes of what Vicor terms Factorised Power. In applications that require telemetry and digital control (e.g., CPU, GPU, ASIC and DDR4 memory applications) a Vicor PI3020 Digital Control and Telemetry device may be used with a VTM/PRM pair. Among the features of the PI3020 are PMBus and SVID control interfaces with full support for server processor power VR13, and backwards compatibility for VR12.5 and VR12.0 designs.
Using a MHz ZVS Buck-Boost topology in a 10 x 14 mm LGA package, the PRM delivers up to 240W at 98% efficiency. The VTM’s MHz ZVS/ZCS Sine Amplitude Converter (“SAC”) delivers up to 95A of continuous current, and up to 190A of peak current, at 95% peak efficiency in a moulded 13 x 23 mm ChiP package with greater than 400 A/in² current density.
The VTM features very low output impedance, allowing users to remove bulk capacitors from the Point-of-Load. Furthermore, only the high current VTM needs to be close to the CPU; the PRM can be located remotely. And, whereas conventional buck regulator solutions require enough phases to handle the full transient current demanded by a CPU operating in ‘turbo’ or ‘boost’ mode, the VTM’s own Turbo Mode delivers up to twice its rated continuous current for up to 10 msec, thereby accommodating transient CPU operating modes without sacrificing system power density and cost.