Power Source

By Staff -- EDN, 6/6/1996

Modular switchers correct power factor.

 Boasting a power density of 4.4W/in.³, the Unimod K series of modular switching power supplies provides power-factor correction as high as 0.99 and output power as high as 1200W. The supplies come in 5- and 6.5-in.-wide chassis. Both chassis are 5 in. high and 11 in. deep. The 5-in.-wide chassis has three module slots for as many as six outputs, and the 6.5-in.-wide chassis offers four slots for a total of eight outputs. You can configure a complete power supply from 29 standard modules with output voltages ranging from 2 to 48V dc. A triple-output configuration in a 5-in.-wide case costs $1195; a quad-output supply in a 6.5-in.-wide case costs $1495. Unipower Corp, Coral Springs, FL. (954) 346-2442.

Reliable CRT power supply hits 18 kV.

 The CRM183 high-voltage power supply, which replaces the M153/02P, offers better efficiency and an MTBF of >80,000 hours for CRT applications. An increase in output voltage to 18 kV also allows you to use the CRM183 in a variety of applications, and an increase in output current to 300 mA boosts maximum power output to 6W. An auxiliary output of 600V at 18 kV tracks the main output voltage. Dynamic response is <50v for a 100-µA change in load at 18 kV. The CRM183 costs $277 (OEM). Advance Power Inc, Solon, OH. (216) 349-0755.

Telecomm power supplies fit 19-in. rack.

 Hot-swappable 500W switching power supplies with isolation diodes come separately or in a parallel redundant configuration in a standard 19-in. rack. Models in the 178 series provide dc outputs of +5V at 70A, +12 or +15V at 10A, -12 or -15V at 1.5A, and -5V at 1.5A. Input voltage is 48V dc (36 to 72V dc) and is floating. Operating at a fixed frequency of 75 kHz, each supply has its own brushless dc fan to achieve full ratings without depending on system cooling. The units cost $402 (1000); redundant systems cost $990 (500). Conversion Equipment Corp, Orange, CA. (714) 637-2970.

Hybrid dc/dc converters sport surface-mount packages.

 The NMETM series of miniature surface-mount dc/dc converters complies with the CECC00802 soldering profile to 280°C, allowing you to place and reflow the devices alongside ICs. Rated for 1W, the converters accept 5 or 12V inputs and supply a single output of 5, 9, 12, or 15V. Input/output isolation is 1000V dc. All types offer conversion efficiencies as high as 75%. The free-air operating-temperature range of the NMETM series is 0 to 70°C. Converters cost $10.89 (1000). Newport Technology Inc, Raleigh, NC. (919) 571-9405.

SIP converters drive dual output.

 Housed in single-in-line plastic packages, a series of 1W dual-output dc/dc converters provides bipolar output voltages and isolation for 5V digital systems. The Dual SIP series comprises six models, offering ±5, ±12, and ±15V outputs or ±7, ±14, and ±17V outputs for driving three-terminal regulators. The input range is 4.5 to 5.5V. Output voltages are semiregulated with load regulation of 4%, cross regulation of 1%, and line regulation of 1.2%. Output noise varies from 15 to 30 µV p-p, depending on the model. Input/output isolation is 700V dc. The converters cost $9.50 (OEM). Calex Manufacturing Co Inc, Concord, CA. (510) 687-4411.

1W surface-mount dc/dc converters shun heat sink.

 In 24-pin DIP and surface-mount packages, the HB01U series of 1W dc/dc converters has standard input voltages of 5, 12, and 24V in single- and dual-output versions with 2500V-rms isolation. All devices are rated for full power at 70°C without an external heat sink. Prices start at <$7 (OEM). Power Convertibles Corp, Tucson, AZ. (602) 628-8292.

300W modules allow N+1 redundancy.

 Hot-swappable power supplies in the RPP series comprise 300W four-output modules in redundant N+1 systems. Units accept a 115 or 230V-ac input with optional auto-switching. Each output is isolated, so that, if one supply fails, the second does not shut down. The redundant power supplies share the total power-supply load, maintaining output regulation within specified limits. Minimum holdup time is 20 msec. The supplies cost $451 (OEM). Total Power International Inc, Lowell, MA. (508) 453-7272.

AC power sources extend frequency, crest factor.

Enhancements to the HP 6814B single-phase 3000-VA and HP 6834B three-phase 4500-VA-ac power sources increase frequency capability to 5 kHz and provide a 4 crest factor for higher peak current. The 4500-VA model also has a programmable-mode switch that adjusts it for single-phase applications. Respective prices for the HP 6814B and HP 6834B are $11,500 and $13,900. Hewlett-Packard, Santa Clara, CA. (800) 452-4844, ext 1496.

AC front end supplies 24, 36, or 48V-dc output.

 Offering power-factor correction and virtually no inrush current, the LT series of universal-input ac/dc converters provides 400W of regulated power in a fully enclosed 4×5×7-in. 3U VMEbus format package. Power increases to 550W for inputs >155V ac. The LT series, which powers dc/dc converters and charges batteries via the backplane, gives you a choice of 24, 36, and 48V nominal outputs. Transient protection is in accordance with IEC 801-4, 801-5, and VDE 160. Total harmonic distortion is 103 better than IEC 555-2 specifications. Prices start at $858 (100). Melcher Inc, Chelmsford, MA. (508) 256-1812.

3-kW UPS triples full-load run time.

The Unity/I uninterruptible power supply (UPS) now provides a full-load runtime of 14 minutes. The 3-kW supply also boasts an on-line efficiency as high as 97%, dual power circuitry for high fault tolerance, and software-controlled battery charging and maintenance. Direct system-to-factory communications allow remote diagnostics. The Unity/I is $3799. Best Power Technology Inc, Necedah, WI. (608) 565-7200.

2600W power supply handles hot insertion.

 The PM33211, an isolated front-end power supply, delivers as much as 2600W from a compact 5×5×14-in. case. A hot-pluggable option lets you insert or remove the unit without shutting down the ac input or affecting the voltages on the dc buses. The supply provides full power at input voltages from 170 to 264V ac, 43 to 63 Hz, at ambient temperatures from -30 to +70°C. With >0.99 power-factor correction, the power supply meets IEC 555-2 requirements. The output of the PM33211 is rated for 48V at 52A. The supply costs <$0.50/w (OEM). Power Magnetics Inc, Santa Monica, CA. (310) 829-6751.

Power-supply front ends meet Bellcore specs.

A series of ac/dc front ends for telecommunications applications satisfies Bellcore requirements. The FE series incorporates power-factor correction and provides 28 or 48V outputs at power ratings of 500W to 6 kW. The supplies offer hot-plug N+1 redundancy and contain integral diagnostics and front-panel status display. Automatic fault reset ensures recovery following overvoltage or overtemperature shutdowns. Price is <$0.70/w (OEM). Lambda Electronics Inc, Melville, NY. (516) 694-4200.

1000W module drives dc/dc converters.

 The UniVerter Model PFC-1000 accepts ac inputs of 205 to 265V and converts those inputs into 380V dc at 1000W to power the RO mV300 series of dc/dc converters. The unit derates linearly from 1000W at 205V ac to 750W at 170V ac. The converter comes in a 0.5×2.4×4.6-in. package and offers power-factor correction that meets IEC 1000-3-2 requirements. Efficiency is 94% at 220V ac and full load. The PFC-1000 costs $150 (100). RO Associates Inc, Sunnyvale, CA. (408) 744-1450. Circle No. 492

Medical switchers cover 40 to 200W.

A family of medical switching power supplies comprises four series of single- and multiple-output supplies ranging in output power from 40 to 200W. Key features include input/output isolation of 4000V ac, a wide input-voltage range of 85 to 240V ac, and leakage current of 50 µA maximum at 110V ac and 100 µA maximum at 240V ac. Package sizes range from 3×5×1.2 in. for the 40W open-frame version to 5×9×2.55 in. for the 200W U-channel series. Enclosed units are also available. Prices range from $37 to $117 (OEM). International Power Sources Inc, Ashland, MA. (508) 881-7434.