PoL modules boost density and efficiency

The modules are being introduced following the Open Compute Project Summit 2016 at which Google announced it will promote 48V server and distribution infrastructure as a standard for ‘green’ data centres to reduce the global cloud electricity footprint.

Conventional power conversion has not been able to efficiently, or compactly, transform power from a 48V bus into low voltages and high currents required by contemporary CPUs or GPUs, relying 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, the 48V Direct-to-PoL modules enable system designers to implement ‘green’ distributed systems with high conversion efficiency, high power density and low distribution loss, says the company.

The 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 “factorized” 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. Where telemetry and digital control is required (e.g. CPU, GPU, ASIC and DDR4 memory applications) a PI3020 Digital Control and Telemetry device may be used with a VTM/PRM pair.

Using a MHz ZVS buck-boost topology in a 10 x 14mm LGA package, the PRM delivers up to 240W at 98% efficiency. The VTM’s MHz ZVS/ZCS Sine Amplitude Converter delivers up to 95A of continuous current, and up to 190A of peak current, at 95% peak efficiency in a moulded 13 x 23mm ChiP package with greater than 400 A/in² current density.

The VTM’s low output impedance allows users to remove bulk capacitors from the PoL. While the high current VTM needs to be close to the CPU, the PRM can be located remotely. The former’s Turbo Mode delivers up to twice its rated continuous current for up to 10ms, to accommodate transient CPU operating modes without sacrificing system power density and cost.