DPA: DISTRIBUTED POWER ARCHITECTURES
DC/DC SOLUTIONS THAT GET TO THE POINT.
How should system tasks be distributed to best minimize costs?
In power-intensive and more complex systems the answer is clear, as the concept of distributing power supply tasks among different modules has been with us for some time now. Today's power systems must cope with steadily increasing current requirements and lower voltages. What's more, the time intervals at which power must be delivered are shrinking all the time. As a result, a universal solution is simply not conceivable.
Will flexibility within a single module solve future needs? Or, will highly specialized modules with comprehensive characteristics pave the way?
The ARTESYN power modules offered by CODICO are clearly designed to provide the latter solution, as they are specialized products designed to meet specific application needs. When using ARTESYN modules, adding flexibility to the overall system is left up to the designer who integrates the devices. The ARTESYN on-board architecture is described below. System voltages remain as previously, namely 48VDC in most cases.
12V Intermediate Bus: Why use an intermediate bus of 12V?
· Stepping down from a high-voltage hub (e.g., 48V à 3V3) would generate a great deal of heat loss, and that must be avoided in the vicinity of a board's high-performance components.
· Using too low a bus voltage (e.g., 5V) results in extremely high board currents, which would in turn require an unmanageably large conductor cross-section; not to mention the undesirable generation of electromagnetic fields.
· The choice of 12V represents an effective compromise. A variety of different manufacturers now offer products that use the 12V bus, which therefore qualifies as a quasi standard.
INTERMEDIATE BUS CONVERTER: Doesn't adding an extra converter increase costs and reduce efficiency?
· Yes, but only minimally, since this design uses a complete 2-step DC/DC converter split into 2 separate modules. The two major tasks are thus performed independently of each other from two separate locations. ARTESYN's TQN20 bus converter, for instance, offers 95% efficiency!!!
· The ARTESYN intermediate converter provides galvanic isolation (2000VDC) and, if required, can handle a wide input range, e.g., 36 to 75VDC (though sacrificing 1% of efficiency to do so).
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· The bus converter is positioned at a point where heat is easily dissipated. The heat dissipation for other connected modules is reduced by this factor, and they generally make do with limited air circulation when mounted in the center of the board.
POINT OF LOAD Converter:
The POL performs the precise regulation without isolation. It is, of course, possible to self-design a discrete solution, which saves board space and optimizes cost!
· The design option can provide an advantage, as long as current can be kept low (up to approx. 3A for the logic voltage). However, most discrete switching regulators either don't provide the necessary functional advantages, or they wind up so large, or complex in design, that an off-the-shelf POL converter makes better sense.
· POL converters not only perform sequencing, but also permit exact control of the rise time and, sometimes, add a synchronization function.
· POLs regulate at rates up to 300A/µs.
· POLs deliver power densities of up to 25W/cm³.
· POLs meet a variety of installation needs (SMT, THD, vertical, or horizontal).
· POLs are production burn-in tested under full load, which is virtually impossible with an assembled board.
· POL converter efficiency typically ranges from 94% to 95%.
· The emergence of standard-platform POL designs gives users a viable multi-sourcing option, which is not the case for discrete designs.
ARTESYN PRODUCT OVERVIEW
Intermediate Bus Converters (IBC):
Construction: quarter brick (58 x 37mm / h=11mm max.)
· Isolation: 2000VDC
· TQN20-48S12: used to convert narrow input ranges: 43VDC - 53VDC à to 12V at up to 20A
· TQW14-48S12: used to convert wide input ranges: 36VDC - 75VDC à to 12V at up to 14A
Point of Load (POL) Converters:
Construction: horizontal or vertical module orientation
Available in SIL and H versions with THD pins, or
in SMT and S versions with SMD pads / SMD balls
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· C-Class: used to convert 5V or 12V à to 0.9 to 3V3 or 0.9 to 5V respectively.
C in this case stands for cost-optimized computing applications.
· E-Class: used to convert 3V3 or 5V or 12V à to 0.8 to 5V.
· E in this case stands for extra performance in terms of efficiency and size.
· POLA: used to convert 3V3 or 5V or 12V à to 0.8 to 5V.
POLA stands for the POINT OF LOAD ALLIANCE, whose members have jointly developed a standard POL platform with a rich set of options to suit a wide range of common applications.
· F-Class: used to convert a 3V3 to 5V input range, or 12V, à to 0.9V to 3V3.
F in this case stands for ultra fast regulation (transient response) on the load side at rates up to 300A/µs, plus a significant reduction in capacitor board space.
Please address all technical questions to:
Michael Schrutka, EXT 31
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