Regulated quarter-brick module handles 750-W for high-power datacom applications
The platform is ideal for applications that require regulated high-power quarter-brick-format intermediate bus converters able to deliver up to 750 W.
To meet the challenge of packing a 750 W regulated DC/DC converter in a quarter-brick format, Ericsson has developed an innovative proprietary topology known as Hybrid Regulated Ratio (HRR). The topology combines two power-control methods – voltage-regulation and ratio-regulation – resulting in high performance across the input voltage ranges used in datacom systems, which are usually between 40 V to 60 V.
The HRR topology implemented in the Ericsson PKM-NH platform delivers an excellent response to line or load transients and guarantees the output voltage will remain stable and immune from voltage deviation due to power disturbances on the system bus voltage. This means it retains intermediate bus voltage integrity within the tolerance band required by power system architects.
The PKM4717NH is the first product in the PKM-NH series. The module operates with an input voltage range of 40 V to 60 V and delivers an output voltage of 10.8 V at 70 A within the operational system voltage between 50 V and 60 V. Below 50 V, in its regulated-ratio mode, the output voltage self adjusts for optimal operation and secures a stable voltage even though the system bus voltage could be operating in abnormal mode. Retaining a stable and regulated voltage while the system bus runs its normal operational voltage becomes a highly important capability to avoid traffic disruption and also to provide enough time for system monitors to take required action, either to turn on redundant power units or potentially to shut down part of the system.
Based on a bus-voltage optimization study carried out by Ericsson, the optimal fixed voltage to limit board conduction losses during step-down conversion at the Point-of-Load (POL) is believed to be 10.8 V in non-‘dynamic-bus-voltage’ applications. This bus voltage is very common in datacom applications that no longer require the standard 12V supply to power disk drives. However, if this level is required for local sub-functions, then step-up POL converters can easily generate a 12 V supply. The PKM4717NH is also perfectly suitable as a replacement for existing 9.6 V intermediate bus applications.
A product of Ericsson’s ‘design-for-efficiency’ principle, the PKM4717NH has a typical efficiency of 97.1% at 60% load and offers flat-curve characteristics from 20 A to 70 A, reducing power losses to the lowest possible level and making a significant contribution to the reduction of energy consumption.
The PKM-NH series implements the high-power industry-standard footprint with two extra power pins to decrease power losses and guarantee optimal current distribution. The two extra power pins were introduced in 2004 and is the most optimized footprint for high-power density DC/DC converters. However, Ericsson also offers an optional version, with the ‘SP’ reference, which is compatible with traditional five-pin intermediate bus converters.
The PKM4717NH provides 2250 V input/output (I/O) isolation meeting functional isolation requirement. The device includes a number of I/O protection and operational features including input overvoltage suppression, soft-start for handling of high capacitance loads, delayed hiccup over-current protection, over-temperature protection, over-voltage and under-voltage lockout, and pre-bias startup functionality.
The PKM4717NH comes in the industry standard quarter-brick format measuring 59.9 x 36.8 x 11.4 mm. The PKM-NH series is also available with a baseplate for applications requiring additional cooling or a cold-wall attachment.
Visit Ericsson Power Modules at www.ericsson.com/powermodules
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