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Save Time and Effort With Custom Linear AC/DC Power Supplies

Save Time and Effort With Custom Linear AC/DC Power Supplies

If you need a custom AC/DC power supply that offers low noise and ripple, simplicity, reliability and economy, chances are the ever-popular switching power supply won’t satisfy all your needs — especially when it comes to low noise. Thankfully, there are still power supply manufacturers that can provide an AC/DC linear power supply that can satisfy requirements for industrial, medical and other critical low noise applications.

Manufacturers typically focus their efforts on switching power supplies, so finding a vendor that offers custom linear supplies can be a challenge. The Polytron Devices Division of Daburn Electronics is one of a few suppliers that are committed to customizing linear power supplies. When specifying a custom AC/DC linear power supply, these are the factors to look for in a vendor:

  • A solid legacy of producing AC/DC linear power supplies
  • A commitment to AC/DC linear power supplies
  • The ability to satisfy high power requirements
  • The ability to provide many types of modifications to linear power supplies
  • Engineering expertise
  • Volume advantages to keep costs low

How We Can Tailor a Linear Supply To Your Needs

As other manufacturers de-emphasize or even phase out linear power supplies, we're building on the legacy of our P3 and P5 Series low noise, precision linear power supplies — continuously available since 1969 — by expanding customization capabilities and upgrading our original designs for medical applications.

At Polytron Devices, we're well-known for low-noise medical and industrial linear power supplies. We can satisfy a wide range of custom needs such as:

  • Providing multiple output voltages in a single model
  • Adding programmability or ON/OFF switches
  • Adding a variety of types such as open frame, desktop and wall plug-in models, in addition to enclosed units for harsh environments

We have also upgraded our power capability. Our previous offering had a range of 1 to 30 watts, maximum, while our latest supplies now cover 1 to 450 watts, maximum. Our engineering staff is available to assist you throughout the process. Simply send us your tech specs and we’ll suggest solutions for your unique requirements, create evaluation samples, safety-test the unit and help ensure regulatory approvals for IT equipment and medical equipment.

We’ll also work to get your custom unit to you when you need it while keeping costs in check. For example, transformers are the most expensive part of the linear power supply. But thanks to our strong relationships with transformer manufacturers, we have access to large quantities of transformers to get them fast and cost-effectively. We also accommodate blanket orders so you can lock in quantity pricing while receiving your product as you need it.

Saving You Time and Effort

Because most power supply manufacturers focus on switching-type supplies, specifying a custom linear AC/DC power supply has become a challenge for designers. We can meet your linear power supply needs with custom units tailored to your application. When you work with our engineers and sales support team, you’ll save time, effort and money so you can get your product to market faster.

For more information about our custom linear AC/DC power supplies, contact us.

What You Should Know About the New IEC 62368-1 Safety Standard

What You Should Know About the New IEC 62368-1 Safety Standard

Technology is all about change, and the design standards for IT and AV equipment are changing with the times as well. IT and AV devices share many similarities, so the International Electrotechnical Commission replaced its longstanding IEC 60950-1 IT equipment safety standard and IEC 60065 AV standard with the new IEC 62368-1 safety standard.

This single standard is a dramatic shift in compliance requirements for IT and AV equipment designers. Here’s a brief overview of just some of the many facets of IEC 62368-1:

  • It’s a hazard-based standard. IEC 62368-1 is a hazard-based, rather than a prescriptive, approach to compliance, with an emphasis on protecting users who come into contact with equipment during operation, installation or maintenance. OEMs must identify potential sources of injury and safeguards that can reduce the likelihood of pain, injury, fire and other incidents.
  • The focus extends beyond products. Not only does IEC 62368-1 cover IT and AV products, but it also covers components and subsystems. Designers purchasing power supplies, components built into equipment or standalone power supplies and adapters should verify the products comply with IEC 62368-1.
  • It has future energy sources in mind. As technology advances, so do energy sources. That’s why IEC 62368-1 requires engineers to identify energy sources and label them as Class 1, 2 or 3 based on a source’s effect on the body, as well as its effect on combustible materials. Engineers must also identify the existing safeguards for each energy source and determine their efficacy.
  • IEC 62368-1 has arrived. IEC 62368-1 superseded IEC 60950‐1 and IEC 60065 on December 20, 2020. Going forward, OEMs have to certify that their new IT and AV equipment satisfies the IEC/UL 62368 standard in order to access major markets.

IEC 62368-1-Compliant DC/DC Converters for Railway Applications

The Polytron Devices division of Daburn Electronics is committed to helping OEMs ensure compliance, starting with a new line of 200-watt DC/DC converters. The HWC200 Series half-brick DC/DC converter offers a 10:1 ultra wide input range to accommodate a broad range of power systems typically found in railway environments. Other features include:

  • A hold-up function
  • 3,000V AC reinforced insulation
  • Primary pulse output
  • Remote ON/OFF
  • Over voltage, over current, short-circuit and over temperature protection

The 10:1 ultra wide input makes the HWC200 well-suited for railway applications because it can accommodate a broad range of power systems. In addition to meeting IEC/UL/EN 62368-1, this RoHS and REACH-compliant DC/DC converter carries the CE mark and meets EN50155 and EN45545-2 standards for railways, as well as EN55032 and EN50121-3-2 for EMC in railway environments.

Meet the Latest Global Safety Standards

When selecting DC/DC converters for new IT and AV equipment, make sure they meet the latest global safety standards. Our HWC200 Series DC/DC converters are IEC/UL/EN 62368-1 certified and also satisfy various railway standards. And, we can furnish the applicable documentation upon request.

For more information about the HWC Series of IEC 62368-1-compliant DC/DC converters, visit our product page.

Constant Current, Constant Voltage DC/DC Converters Prevent Component Damage

Constant Current/Constant Voltage DC/DC Converters Prevent Component Damage

While many DC/DC converters maintain a constant voltage output, some devices in a design may instead call for steady current. For instance, LEDs require a constant current to prevent burn out. Other components that operate from a constant current include batteries and supercapacitors. Here are the things you need to know about DC/DC converters that provide both constant current and constant voltage (CC/CV) regulation.

DC/DC converters with a constant current mode use a resistor and feedback loop to deliver a steady output current which is unaffected by load variations. Similarly, a constant voltage mode uses a control loop to provide steady voltage output even when load resistance varies.

Ensure Steady Power for Railway Applications

Polytron Devices’ FWB(D) Series of DC/DC converters for railway applications offers constant current and constant voltage capabilities to ensure steady power delivery. The 150W devices can operate at up to 200W with 20 percent output voltage adjustability, and the output current can operate 1.1 times and above when in CC mode. It also provides hiccup protection mode to facilitate recovery from an overcurrent condition if the output resistance is short.

The FWB(D) Series comes in a 3.68 by 2.07 by 0.067-inch wall mount package and accepts 4:1 wide input voltages of 9-36, 18-75 and 43-160V DC and provides adjustable output voltage from 12 to 48V DC with no minimum load required. In addition to offering constant current and constant voltage modes, the series also features:

  • High efficiency up to 89 percent.
  • Built-in EN55011 and EN55022 Class A filter.
  • Input to output isolation: 2,250V DC.
  • Six-sided continuous shield.
  • UL60950-1, EN60950-1, IEC60950-1 and EN50155 approvals.
  • CE Marked.
  • RoHS and REACH compliance.

Achieve Optimal Operation and Reliability

Constant current/constant voltage DC/DC converters can provide steady voltage if needed or can vary that voltage to guard against high currents, depending on your application. Polytron Devices’ FWB(D) Series DC/DC converters combine voltage and current regulation with exceptional power conversion characteristics so the components you use in your railway applications can operate with optimum performance and reliability.

For more information about Polytron Devices’ FWB(D) Series constant voltage/constant current DC/DC converters, visit our product page.

DC/DC Converter Considerations for Portable Medical Device Designs

As medical equipment migrates from hospital environments to doctors' offices and even patient homes, designs are getting smaller. Chances are these portable devices will require a power management device to regulate a supply voltage to, for example, maintain battery life. While DC/DC converters are essential for many portable devices, low-power, compact, medical equipment presents designers with some key considerations when specifying a DC/DC converter.

Medical Device Designs

The most important consideration is patient safety. In order to prevent accidental electric shock to patients, power products must meet IEC 60601 medical standards which establish isolation, insulation and creepage classifications for patient protection. The most stringent classification for patient safety is 2 x MOPP. Here are some other factors to consider when selecting a DC/DC converter for portable medical devices:

  • Efficiency can affect device size, thermal performance and cooling, battery life and other factors.
  • A small footprint to allow for smarter use of already limited board space.
  • A wide input voltage range between minimum and maximum allowable input voltages offers greater design flexibility to accommodate many mains or battery powered medical device designs.
  • Circuit protection features to prevent electrical threats from affecting the device’s reliability, patient safety or damaging other components.


A DC/DC Converter That Addresses Many Requirements

Polytron Devices’ MTWA4 DC/DC converter series checks many of the boxes that portable medical devices require. This 3.5-watt unit meets IEC 60601 standards for medical equipment safety, offers 2 x MOPP patient protection and exhibits a low leakage current of 2 µA. The 2:1 and 4:1 inputs include a 4.5 to 12V DC range, which is wider than the standard 4.5 to 9V DC input and not always easy to find. Other inputs are 9 to 18V DC, 18 to 36V DC and 36 to 75V DC.

The RoHS-compliant MTWA4 comes in miniature DIP16 (0.95 by 0.57 by 0.41 inches) and SMD16 (0.95 by 0.57 by 0.40 inches) packages, making it well-suited for small devices. MTWA4 DC/DC converters offer up to 82 percent efficiency, and built-in safeguards include overvoltage, short circuit and undervoltage protection. A 2-watt version (MTWA2) is also available.

Look for Safety, Reliability and Design Flexibility

When it comes to shrinking medical equipment designs, not all DC/DC converters are the same. In addition to selecting a converter with a small footprint, be sure to look for converters that meet IEC 60601 standards for patient safety, good efficiency for reliable performance and built-in safeguards to ensure circuit protection. Polyton Devices’ MTWA4 3.5-watt DC/DC converters provide both patient protection and reliable operation plus a wide input for additional portable medical device design flexibility.

For more information about Daburn Electronics’ Polytron Devices MTWA4 3.5-watt DC/DC converters, visit the product page.

Limited Power Source Requirements Help Lower Safety Risks


Many power supplies come with a limited power source (LPS) rating to indicate they pose a reduced likelihood of danger to users. When applicable, manufacturer product pages or data sheets will indicate that the unit is LPS compliant. Because this rating typically appears amid a long list of features and specifications, it’s easy to lose sight of its importance. Here’s a quick overview of what you should know about LPS as you make your selection.

When selecting power supplies, it’s important to remember that power products can potentially present safety risks. LPS is a requirement within the IEC/UL 60950 safety standard for information technology equipment that establishes a maximum output voltage, output current and outdoor power rating for power supplies under normal operating conditions or single-fault conditions. With these limitations, system installers — who may not know all of the various potential fault conditions when choosing wire and cable — can recognize an LPS product as having a reduced risk of electrocution or fire.

Here is a partial summary of the criteria a power supply must meet for LPS compliance. For the complete criteria, be sure to reference the IEC/UL 60950 standard. Note that LPS requires that the unit meet both the current and apparent power limits for output voltages of 30V or less:

  • Output voltage 30V or less
  • Output current 8A or less
  • Output power 100W or less

If the supply has an output voltage greater than 30V up to 60V:

  • Output current cannot exceed 150 ÷ Vout
  • Output power 100W or less

Polytron Devices’ UI72/PA AC-DC power supplies are designed to comply with the LPS standard. These single-output industrial power supplies come in a 4.45 x 1.93 x 1.38 inch (113 x 49 x 35 mm) package and offer outputs from 25 to 72 watts, depending on the model. In addition to compliance with IEC/UL 60950 LPS maximum permitted output ratings, built-in safety features include over current, over voltage and short circuit protection. Over temperature protection is available as an option.

Additional features and specs include:

  • DoE/CoC Tier II compliance
  • LED indication
  • MTBF of 100,000 Khrs.

LPS Compliance Means Less Worry

Your power supply vendor’s datasheet or product page should indicate whether the unit meets LPS specifications. Selecting an LPS-compliant power supply can mean less worry of fire or electrocution, and in some instances, selecting an LPS-compliant power supply may allow you or your system installer to follow relaxed wiring and installation requirements. Our UI72/PA AC-DC power supplies conform to the LPS standard and include built-in protections to give you the reliability industrial systems demand plus enhanced safety characteristics.

For more information about Polytron Devices’ UI72/PA AC-DC power supplies, visit the product page.

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