Electronic Design

Power Supplies Keep Developing Even After They Are Introduced

Usually, new components only make headlines when they're first introduced. However, additional details will often surface after a product launch, or a competitor's announcement of something similar may offer another perspective. But in the power-supply arena, where one announcement seemingly begets another, it appears as if every development is a work in progress. With that in mind, I'd like to update a few of the power-related articles that ran in Electronic Design this year.

The cover of our August 19, 2002 issue highlighted the Pisces II high-efficiency dc-dc converter from Galaxy Power ("60-A Quarter-Brick DC-DC Converter Keeps Its Cool,"p. 41). The story included graphs depicting the converter's efficiency and power losses. Yet it did not include derating curves, which only recently became available (www.galaxypwr.com).

Comparing the curves against the data in the article shows they support the claim that the Pisces II delivers 40 A with no moving air at ambients of up to 50°C. However, they don't uphold the rating of 60 A up to 60°C with 200 LFM of airflow. The curves indicate that 60 A at 60°C requires about 600 LFM. But Andrew Ferencz, Galaxy's vice president of technology, notes that with a 0.5-in. high heatsink attached, the converter will achieve the 60 A, 60°C rating at 200 LFM. For more details on the derating curves, send e-mail to [email protected].

If the Galaxy news piques your interest, you may want to compare the Pisces II with two 60-A quarter bricks that were subsequently announced. One was Glary Power Technology's CPQ series (www.glary.com/CPQ.htm), which also specifies 60 A at outputs up to 2.5 V. Another was Broadband TelCom Power's SHQ series (www.btcpower.com), which offers 60 A up to 1.8 V. Also consider the 45-A QmaX series from di/dt (www.didt.com). This model specifies high current capability up to 70°C. Another quarter-brick contender is Tyco Electronics' 50-A QPW050A (www.power.tycoelectronics.com). For those with less of a space restriction, newer 60-A half bricks like Astec Power's ALH60/AEH60 and Power-One's HHS60 may additionally provide interesting comparisons.

In a Sept. 16 article, "Distributed Power Moves To Intermediate Voltage Bus" (p. 55), I discussed the growing use of nonisolated point-of-load (POL) converters in distributed power schemes. In response, Ron Wunderlich, vice president and CTO of Excalibur Capital & Manufacturing (www.xcapmfg.com) wrote of his company's alternative to bricks and SIP-style POLs.

Excalibur's PwrDIMM Power Module is a POL on a DDR memory card. It steps down a 12-V input to a 1.2- to 3.5-V output at up to 40 A. Wunderlich writes, "This approach has the advantage that the connector system and associated manufacturing processes are well known and easily handled."

Much earlier in the year, I described Metallic Power's efforts to develop a long-running UPS based on a zinc-air fuel cell ("Fuel Cells May Beat Batteries For Backup," Feb. 18, 2002). The company is now advancing beyond the prototype stage with the shipment of its first production units last month.

The 54- by 72- by 24-in. UPS delivers 24 hours of runtime at 1 kW, or up to 5 kW if units are paralleled. For more details, visit www.metallicpower.com/products/stationary.htm. Follow-up news of this nature places the original announcement in a whole new light. Moreover, for those tracking the progress of fuel cells as a whole, it provides further proof that the technology is indeed real.

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