Front-End Power Supplies Feature 80 Plus Platinum Standard Efficiency and PMBus

Emerson Network Power launched two ultra-compact ac-dc front-end power supplies that meet the 80 Plus Platinum standard for efficiency. Rated at 750W and 1,100W continuous output, the power supplies share the same form factor, providing the scalability that system designers need for long life cycle applications where power requirements may change in the future. Designed primarily for space-constrained, high-availability applications such as ‘always on’ enterprise servers, Emerson’s new 750W DS750PED and 1,100W DS1100PED power supplies are both housed in 1U high rack-mounting enclosures measuring 3.4 x 7.7 inches (86.3 x 196.5 mm).

This form factor is significantly shorter than that of similarly rated earlier-generation power supplies – freeing up valuable system space – and is achieved by use of the latest power switching technology and high density component packaging techniques. Both power supplies combine a conversion efficiency of 94 percent peak with a high power density; the DS750PED provides up to 16.4 W/in3 (1 W/cm3), while the DS1100PED can deliver 24 W/in3 (1.46 W/cm3).

Capable of operating from any input voltage in the range 90 to 264 Vac, the power supplies use active power factor correction to maximize efficiency and ensure compliance with the international EN 61000-3-2 standard for harmonic current emission. Unlike many power supplies on the market, which only have a power factor approaching unity when under full load, the DS750PED and DS1100PED have a power factor of at least 0.9 for all load conditions from 20 percent to full output. This simplifies the design of power distribution systems that use current sharing to boost output or active redundancy to increase fault tolerance, by ensuring paralleled power supplies operate at peak efficiency even when only partially loaded.

DS750PED and DS1100PED power supplies are fully digital and compatible with Emerson’s universal PMBus™ graphical user interface, allowing control via an integral I2C interface using the industry-standard PMBus communications protocol. Each power supply generates a main payload output of 12 Vdc for feeding downstream dc-dc converters in systems using distributed power architectures, together with a 12 Vdc standby output rated at 3 A for power management circuitry. The main dc output of the DS750PED and DS1100PED can deliver up to 62.5 A and 91.6 A respectively, and stays within regulation down to zero load. Active current sharing helps maximize cost-effectiveness by eliminating the need for additional components when paralleling multiple power supplies for very high current applications.

Emerson DS750PED and DS1100PED power supplies feature built-in ORing. Inrush current is limited to 38 A on the DS750PED and 55 A on the DS1100PED. Extensive performance monitoring facilities enable system integrators to implement sophisticated power management schemes – in addition to input and output voltage and current, real and reactive input power and power supply temperature values can be retrieved via the I2C bus interface.