To address the need for increased power, yet compact size, in today’s medical electronic systems, Power Sources Unlimited has announced the PMP120 Series if 120W AC/DC external power supplies. Measuring only 6.3″ x 3″ x 1.72, the PMP120 Series is offered with either Class I (with ground) or Class II (no ground) AC inputs, a growing need for portable medical devices. Units are approved to worldwide EN60601-1 standards for safety and EMC performance.
The Series has a power factor corrected, 90-264VAC input, and offers single output models ranging from 12VDC to 48VDC. Input to output isolation is 4000VAC and leakage current is specified at 150uA maximum at 240VAC.

Achieved efficiency is 85% typical, allowing the unit to operate without a cooling fan, ensuring quiet operation and high reliability. The operating temperature is 0C to +60C, with derating after 40C. No minimum load is required and units boast 5% total regulation. Ripple and noise is specified at 2% peak-to-peak maximum and units feature comprehensive protection circuitry.

Pricing starts at $89.00 for 100 pieces with delivery from stock to 8 weeks ARO. Full specifications and online procurement is available at http://www.psui.com, or contact us at 800-966-7784, sales@psui.com.

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A new method to enhance the power density
of Strong current switching power supply

As to the DC power supply, especially the strong current DC switching power supply and DC/DC convertor, its miniaturization is one of the key elements to apply it in broader fields.

As to all kinds of DC power supplies, no matter it is a commute power supply(50Hz),frequency conversion switch power supply or DC/DC convertor, it must face a unavoidable reality: under the same output voltage quality and working frequency, when the output current is strong, the volume of DC power supply is near direct ratio to the output current’s square. So,it is difficult to produce DC power supply with stronger output DC current, even it is impossible.

So,in the situation of requiring output DC current between hundreds to thousands amp, many small power supplies are parallel connection. Of course,it is not good but we have no choices.

As for DC power supplies and DC/DC convertors, The main method is increasing working frequency for enhancing the power density and minishing the volume(weight). But it makes the switching power spoilage larger, and it also makes the effects of components’ autoeciousness parameters and distributing parameters worse. Although this method has been developed largely, it is no much space for further development because of the design mode.
Since 20KHz revolution in 1970s, switching power technology without utilizing industrial frequency transformers has become fashionable around the global. In the past ten years, the design methods, which are mainly based on PWM and soft switching techniques, increase the power density by increasing the working frequency. Although all kinds of soft switching techniques and various kinds of topology based these techniques have been adopted, further increasing unit frequency and power density, and at the same time, decreasing unit size, has become more and more difficult. This is especially true when building lower voltage and larger voltaic DC/DC Converters. This difficulty is due to the tradeoff between the improvement of working frequency and the wastage of the switches.

With multi-year research effort, we’ve invented a set of new methods for enhancing the power density of switching power supplies and DC/DC convertors: By this method, we redesign main parts of power supply and the relations of them. Under any current, the volume(weight) is only near direct ratio to the output current. By all appearances, the output current is stronger, the result of miniaturization volume is distinct.

In this way,the volume(weight) of switching power supply and DC/DC convertor with strong output current(such as hundreds amp) is much smaller than that designed by traditional method. This method also makes it possible to produce stand-alone DC power supplies with stronger output current(such as thousands amp).

At the same time, this method means that enhancing the power density dose not rely on increasing working frequency, and we can reach a higher power density under a lower working frequency. Under any switch working frequency, the volume(weight) of switching power supply and DC/DC convertor with hundreds amp current is reduced to less than 50% compareing to other products under the same situation. In the situation of requiring output DC current between hundreds to thousands amp, it is not necessary to adopt many small power supplies parallel connection, but to adopt one power supply

full article:

http://www.china-power.net/_doc/product/wangduzhi_200717145030.pdf

inventer:Duzhi Wang Senior Electronic Engineer.
Unit 2,Room 301,Shui Wen Xin Su She No.195 Lu Mo Road, Wuhan China
Tel: 00862787596180 (Chinese only) Email: wangduzhi@yahoo.com.cn
FAX: 00862787596180 Post Code: 430074

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Easton, PA – January 11, 2007 – Output ranges from 0-6 to 0-100 Vdc, rated to 270 watts, are provided by Acopian’s Series Y programmable power supplies. Linear regulation limits output ripple to <0.25 mVrms, and line/load regulation in constant-voltage mode is ±0.005% or 2 mV, so these supplies are ideal for use in test equipment, analog systems and R&D.

They can be voltage programmed with an external potentiometer or switched resistance, or with a 0 to +10 Vdc control voltage. Input ranges are 105-125 or 210-250 Vac, 50-400 Hz. All models are UL recognized.

Operating temperature range is -20 to +71°C. Storage temperature range is -55 to +85°C. Output is floating; either positive or negative terminal may be grounded or floated up to 300 volts above ground. The temperature coefficient is typically 0.02%/°C.

Detailed specifications and drawings are available on the Acopian website: www.acopian.com/wao-details.html. Prices start at $195.00. Modular models are shipped within three working days and rack mounted models within nine. All models come with a full 5-year warranty.

About Acopian
Acopian has been designing and manufacturing power supplies since 1957. Standard models have outputs from 1V to 30kV, and up to 1200W. Each is shipped within 3 days (larger units ship within 9 days) after receiving an order. If no standard model meets your needs, we can customize a model for you, or design a ‘special' for your unique requirements. Acopian also manufactures Redundant power supplies in three form factors: rack mounting, (some with power supplies that plug in from the front), wall mounting modular, and multiple output power systems. All systems come with a full 5-year warranty and are shipped within 9 days.

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Ashland, MA — Schaefer, Inc. has introduced the C/B 6400 Series of 22,000 Watt, 8U high, 19″ wide rack mount DC/DC and AC/DC converter modules. This compact and robust design provides a high density, space-saving solution for high power applications in industries such as railway controls and communications equipment (onboard and trackside), military applications, fuel cell applications, transportation, telecommunication systems, process control systems, and power stations.

The C/B 6400 Series is available in 2 standard DC input voltage ranges of either 320-640VDC or 450-800VDC, as well as 3-Phase AC input voltages of either 3 x 400VAC or 3 x 480VAC. Battery charging models are also available. Single outputs are available in 8 standard ranges from 45-800VDC. All outputs are adjustable and tightly regulated to 0.2% or better (load) and 0.1% (line).

All modules in the C/B 6400 Series feature front to back cooling with a standard operating temperature of -20°C to +75°C (derate above +55°C), with an option for -40°C. All C6400 models have remote sensing (up to 150V output). All Series’ models have overvoltage protection, current limit protection on the output, and thermal shutdown with auto restart. Efficiencies run up to 95%

These highly dense units are packaged in a 8U x 19″ x 552mm (HxWxD) rack module for space savings and incorporate terminal / bolt / bar connection points. Options available include decoupling diodes for parallel / redundant operation, “ruggedization”, inhibit, Power Fail / DC-OK alarms, system reset, active current sharing, and programming/monitoring.

Mechanical and electrical modifications to standard modules are readily available upon request. In addition, Schaefer can design and manufacture fully custom solutions. Contact Schaefer, Inc. for Series pricing.

For further information, please contact Sue Gillogly (sgillogly@schaeferpower.com) at Schaefer, Inc., 200 Butterfield Drive, Ashland, MA 01721. Tel: 508/881-7330 Fax: 508/231-0861.

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