DC/DC converters deliver higher efficiency and greater flexibility

DC/DC converters, either isolated or non-isolated, are segmented by input/output voltage, power, and isolation working voltage. They also come in a variety of form factors, ranging from SIP and DIP packaging to DIN rail, chassis-mount, and brick styles.

The global DC/DC converter market is forecast to reach $17.6 billion by 2026, up from $9.9 billion in 2021 and growing at a compound annual growth rate of 12.1%, over the forecast period, according to a MarketsandMarkets report. The big challenges faced by DC/DC converter manufacturers continues to be higher efficiency, dealing with heat generation and noise, the need to operate in harsh environments, and miniaturization.

Some of the biggest markets driving these requirements over the past year include railway, space (satellites), industrial, and portable electronics applications. Here’s a sampling of DC/DC converters that meet these applications.

Railway and industrial

Delivering higher efficiency, operation in harsh environments, greater flexibility, and  meeting safety regulations are four primary goals of DC/DC converter manufacturers in the railway and industrial segments. One example, targeting light-rail and industrial applications, is Powerbox’s PRBX ENR500D, a high-efficiency 750-VDC input DC/DC converter. The switching stage of the ENR500D DC/DC converter is based on an enhanced resonant topology, providing a high efficiency of 95% typical across the low (20%) to high (100%) load range. It is also combined with the latest MOSFET technology and high-performance magnetics.

A variety of electrically powered traction systems are used in rapid transit systems around the world, with most metros operating from DC power either at 750 VDC with a third rail or 1.5 kV with a third rail or from an overhead catenary, said Powerbox. A 750-VDC voltage is very common in light rail, powering both the rolling-stock equipment and trackside signaling systems as well as in industrial equipment and other applications such as mining, added the company.

The ENR500D has a nominal input voltage of 750 VDC and operates within a range of 500 to 900 VDC. The nominal output voltage is set to 48 VDC, though it can be adjusted up to 60 VDC. Nominal output power is 500 W constant across the temperature range of –40˚C to 70˚C in natural cooling conditions. Designed to reduce energy consumption in systems, at no load, the ENR500D input power is less than 5 W.

Designed for a range of light-rail and industrial applications, the ENR500D can be modified to offer other output voltages such as 12 V or 24 V. Different output powers can also be provided in optimized mechanical formats. The ENR500D is enclosed in an aluminum chassis with an integral heat sink. It measures 163 × 230 × 80 mm.

The ENR500D is designed to comply with the EN 50124-1 standard and Pollution Degree 2 (PD2) such as control cabinets in the driver’s cabin or passenger compartments. The ENR500D has ingress protection to IP20 and input-to-output double-reinforced isolation. The unit meets EMC emissions and immunity, as specified in both EN 50124-1 and EN 50124-5.

Cincon Electronics Co., Ltd. is also developing DC/DC converters for railway applications. Integrating the power module easily into railway applications is a big concern for power supply manufacturers, requiring the modules to be adaptable to the system or environmental variations, said the company.

One of its newest DC/DC converters, targeting railway applications, offers this flexibility with an ultra-wide input range that can support all nominal voltages for train-borne applications. The 16:1 EC7BW18-ECRT/EDRT DC/DC converter module offers an ultra-wide input voltage range of 10 VDC to 160 VDC and is available in chassis-mount or chassis-mount with DIN-rail options.

Described as a turnkey DC/DC converter, the series offers 20 W of output power at single-output voltages of 5, 12, and 15 VDC and dual-output voltages of ±12, ±15, and ±24 VDC. Isolation (input to output) is rated at 3,000 VAC. Efficiency can go as high as 88% and low, no-load power consumption is 8 to 10 mA. The case operating temperature range is –40˚C to 100˚C. Protection features include undervoltage lockout, overcurrent, overvoltage, overtemperature, and short-circuit.

The DC/DC converters are certified to the EN 50155 and EN 45545-2 standards. They also meet UL62368-1 & IEC62368-1 safety. Although designed for railway applications, these converters can be used in other applications such as industrial, telecommunications, battery-operated equipment, and distributed power architectures.

Also designed for railway as well as other high-reliability applications in harsh environments is the THN 30WIR series of 30-W DC/DC converters from Traco Power. The series extends the company’s portfolio of EN 50155 railway-certified wide-input-voltage–range DC/DC converters in a 1 × 1-inch encapsulated metal package for the lowest susceptibility to electromagnetic interference (EMI). The full encapsulation guarantees high resistance to thermal shocks as well as mechanical shocks and vibration, said the company.

Thanks to its power-conversion efficiency of up to 91%, the THN 30WIR can operate at ambient temperatures ranging from –40˚C up to 65˚C without derating and without the need for additional cooling. The series offers a wide 4:1 input voltage range of 9–36 VDC, 18–75 VDC, and 36–160 VDC and up to 3,000-VDC I/O isolation. Protection features include undervoltage lockout, short-circuit, overvoltage, and overtemperature. It also offers a remote on/off and trim function.

The THN 30WIR is EN 61373–certified for mechanical shock and vibration and EN 45545-2–certified for fire behavior. It comes with IEC/EN/UL 62368-1 safety approvals.

For the industrial market that covers a wide range of applications, DC/DC converter manufacturers often find they have to balance performance and cost while meeting high-reliability requirements.

Flex Power Modules has expanded its PKE series of through-hole, encapsulated, board-mounted DC/DC converters with the launch of 30-W dual-output variants. The new PKE532x and PKE332x series variants with higher-powered dual outputs target high-reliability applications in which cost is a key consideration, including industrial and communication electronics, instrumentation devices, and mobile and battery-operated systems.

The PKE532x series offers an 18- to 75-VDC (100-V peak) input range suitable for 24-, 28-, or 48-V nominal voltages and the PKE332x series input range is 9–36 VDC (50 V peak). Both parts are available with either ±12-V or +/15-V fully regulated dual outputs, with power ratings of 30 W total.

The DC/DC converters are housed in a 1 × 1 × 0.4-inch format with a five-sided shielding metallic case. Encapsulation ensures reliable operation in demanding environments with high shock and vibration or dust and humidity.

A key advantage of the new variants is their capability to operate to over 100˚C ambient with airflow and derating, thanks to their “exceptional” efficiency, said the company.

Input-output isolation of the DC/DC converters is 1,500 VDC, which meets basic insulation and safety requirements, according to IEC/UL 62368-1. EN 55032, CISPR 32, and FCC part 15J EMC conducted emissions standards can be met with an external filter, specified in the product datasheets, said Flex Power Modules. Typical efficiency is 88%.

Other features include remote on/off control and protection against overtemperature, input undervoltage, output overvoltage, overcurrent, and short-circuits.

Cosel Co., Ltd. has expanded its value-added STMGF platform with the addition of an 80-W DC/DC converter for industrial applications. Available in two versions, the STMGFS80 covers a wide input voltage range from 9 V to 76 V.

The STMGFS8024 operates from 9 VDC to 36 VDC for 12-V and 24-V systems, while the STMGFS8048 works from 18 VDC to 76 VDC, covering industrial 24-V and 48-V systems. Four output voltages are available: 3.3 V/18 A, 5 V/16 A, 12 V/6.7 A, and 15 V/5.4 A. The output volage can be adjusted by a potentiometer included on the motherboard. The STMGFS80 has a typical efficiency of up to 92%.

Using Cosel’s MGFS80 DC/DC converter assembled on a carrier board, the STMGFS80 series fits in the same footprint as its predecessor, which previously delivered only 30 W. The STMGFS80 is ready to use out of the box and includes terminal blocks, an output voltage potentiometer, an input filter, and extra capacitors. The series complies with safety standards UL62368-1 and C-UL EN62368-1.

Optimized for convection cooling, the power supplies can be operated within an ambient temperature range of –20˚C to 70˚C. Depending on the assembly method and ventilation levels in the final equipment, a derating may apply as specified in the technical documentation, said Cosel.

The STMGFS80 series includes overvoltage and overcurrent protection. In the case of overcurrent exceeding 105% rating, said Cosel, the module operates in hiccup mode and automatically recovers when the output current returns to normal.

The open-frame STMGFS80 series measures 52 × 29 × 117 mm (2.05 × 1.14 × 4.61 inches) and weighs 170 grams max. It can be assembled directly to the end-equipment chassis by fixing the base plate using the two mounting holes. It can also be clipped to a DIN-rail chassis. Additional options will be available, including a plastic cover or combined DIN and cover.

The STMGFS80 series has a five-year warranty and conforms to the European RoHS, REACH, and Low Voltage Directives.

Advanced Energy has expanded its LGA family with the release of the Artesyn LGA110D, a 110-A–rated, non-isolated digital point-of-load (POL) DC/DC converter. The company claims the LGA110D delivers a higher current rating at 30% higher power-conversion density than DC/DC converters in its class. Target applications for the POL DC/DC converter include a broad range of industrial, medical, telecom, and IT infrastructure markets.

Due to its power density, the LGA110D increases operational efficiency to more than 96%, and the higher peak efficiency reduces power dissipation by 15% compared with older generations in the same small form factor, said the company.

The LGA110D offers current density of 220 A/in.². The DC/DC converter features two independently controlled 55-A/175-W outputs, which means fewer power converters are needed in multiple-channel or high-current applications, said Advanced Energy.

The dual outputs can be selected as independent, configured to a single output or synchronized with up to three other LGA110D converters. This saves PCB space and reduces overall system cost while addressing the increasing current requirements in FPGA or ASIC devices used in complex applications, said the company.

With both analog and digital control functions, the LGA110D can be controlled with external resistors or the PMBus digital interface that features additional control functions for greater system integration flexibility.

Targeting IGBT and SiC-based MOSFET high-voltage gate drivers in industrial, renewable energy, and mobility applications, Murata Electronics introduced its MGJ2 series of surface-mount DC/DC converters. The series is comprised of six models, each with a 2-W power rating, housed in low-profile modules, measuring 19.49 × 14.99 × 4.39 mm. Available in 12-V and 15-V voltage rails, they feature 15-V/–5-V, 15-V/–9-V, and 20-V/–5-V bipolar outputs.

The DC/DC converters offer ultra-low isolation capacitance of 3 pF, which helps to mitigate the coupling of transients across the isolation barrier and prevent EMI issues generated by high-frequency signals. The series features a common-mode transient immunity that exceeds 200 kV/µs, which allows the devices to handle high switching frequencies.

Other key features include a built-in short-circuit protection, a continuous barrier that withstands voltage that reaches 2.5 kV plus 9-mm creepage and clearance separation distances, and an extended operational temperature range of –40˚C to 100˚C. The series is certified UL62368-compliant for 250-VAC reinforced insulation, and ANSI/AAMI ES60601-1 certification is currently pending.

Space and satellites

In addition to meeting similar requirements for high-reliability railway and industrial applications, DC/DC converter manufacturers in the space market also need to ensure that their converters offer a high radiation tolerance.

One example is the SCD51028xx converters from CAES. The company has claimed the industry’s first single-stage, isolated DC/DC converters for high-throughput satellite payloads. These single-stage converters, compared with traditional two-stage DC/DC converters, increase power efficiency from approximately 80% to more than 90%, while simultaneously reducing size, weight, and power requirements, said the company.

Designed for aerospace and high-reliability space applications, the 28-V SCD51028xx converters offer a total dose radiation tolerance of 50 krads (Si). The converters weigh 50 grams and are available in a 2.5 × 1.5 × 0.63-inch, gull-winged power package that enables surface-mount installation and a low-impedance interconnect with the system board. The operating temperature range is –40˚C to 125˚C.

In addition, the 28-V radiation-tolerant converters are reportedly the first satellite single-stage power supplies to incorporate gallium nitride (GaN) FET technology. The GaN-based devices enable higher performance and switching frequencies, which is said to improve response time to changing load currents compared with silicon-based DC/DC converters. They can also be used in parallel for higher-power applications.

By converting power straight from the power bus to the point of load, the single-stage converters operate within the voltage tolerances of leading-edge processing devices, said CAES. This includes deep-submicron ASICs and FPGAs used in software-defined payloads that can be reprogrammed in-orbit to extend the mission life of space applications, added the company.

The GaN-based converters comply with U.S. Department of Commerce Export Administration Regulations (EAR99) and are commercially available worldwide. The devices provide fully tested, off-the-shelf power-conversion solutions.

VPT, Inc., a HEICO company, is also a manufacturer of DC/DC converters for space applications. One of the company’s latest introductions is the addition of the 50-V input SVL series of space-qualified isolated DC/DC converters. These include the SVLFL, SVLHF, SVLTR, and SVLSA Series. The new 50-V input SVL converters meet the same radiation-tolerance levels of the SVL 28-V input series of 60-krad total ionizing dose and single-event-effects capability (85 MeV/mg/cm²).

The SVL series of DC/DC converters offers a wide input voltage range of 30 to 60 V with an 80-V transient capability and are designed for space applications in harsh radiation environments, with guaranteed performance through the use of hardened semiconductor components, radiation lot acceptance testing of non-hardened components, and analysis, said the company.

The series operates over the full military temperature range of –55˚C to 125˚C, with no power derating. It is suited for use in low Earth orbit (LEO), medium Earth orbit (MEO), geostationary orbit (GEO), deep space missions, and launch vehicle programs.

The SVLFL (120 W), SVLTR (40 W), SVLHF (20 W), and SVLSA (6 W) will be qualified to MIL-PRF-38534 Class H and Class K, pending DLA approval. The availability of the SVL Series is subject to all applicable U.S. export license restrictions and regulations.

Space savers

There is a range of reasons why designers need space-saving components, from the need to pack higher functionality to saving cost by shrinking the PCB size. DC/DC converter manufacturers, like most other component makers, also need to develop smaller devices for space-constrained applications.

Recom, for example, has recently added 1-W and 0.5-W options to its SOIC-16 family of DC/DC converters. The SOIC-16 package measures 10.35 × 7.5 mm with a 2.5-mm profile.

Designed as a low-cost alternative to its higher-spec SOIC-16 devices, the DC/DC converters feature 5-V (4.5–5.5 V) inputs and a semi-regulated 5-V output rated at either 0.5 W (R05C05TE05S) or 1 W (R05CTE05S). Line and load regulation figures are specified across the full temperature range, and there is no minimum load requirement, making the parts suited for applications that have light-load operation modes.

Both parts offer a 3-kVDC/minute (basic) insulation rating with greater than 8-mm input/output creepage and clearance, isolation capacitance of 7 pF, and an operating temperature range of –40˚C to 125˚C with derating. The devices also have built-in protection features, including short-circuit, overcurrent, overtemperature, and input undervoltage. EMI levels are also low compared with more expensive competing products, according to the company.

Applications for the two ranges include isolated COM port power supplies, gate drive power, current sensing/smart metering, medical devices, industrial PLC (I/O), and sensors for IoT/IIoT.

Targeting a range of board-level power-distribution applications, the MD1000RU series from MicroPower Direct (MPD) provides 10 W of tightly regulated output power in an industry-standard SIP package. The low-cost single- and dual-output DC/DC converters are all packaged in a miniature SIP case that measures 0.86 × 0.37 × 0.48 in. (22.0 × 9.5 × 12.2 mm).

Featuring high power density, the MD1000RU devices offer efficiency to 89%, an input/output isolation of 2,250 VDC, a remote on/off control input, and low noise operation. The 14 models operate from 4:1 inputs of 9–36 VDC and 18–75 VDC, providing single and dual outputs of 5, 12, 15, 24, ±5, ±12, or ±15 VDC. The devices operate over the industrial temperature range of –40˚C to 85˚C, with no heat sinking required. Cooling is by free-air convection.

All models are protected for overvoltage, overcurrent, and short-circuit faults. The MTBF of the MD1000RU series (per MIL HDBK 217F) is over 1.9 Mhours. The pinout is industry-standard, and all case materials meet UL94-V0 requirements.

CUI Inc. also is expanding its line of miniature DC/DC converters. The company recently added four ultra-thin converter series to its isolated DC/DC converter line. Targeting portable electronics applications, these 3-W DC/DC converter series include the open-frame PYBJ3-OD series in a six-pin DIP package, the encapsulated PYBJ3-D series in a six-pin DIP package, the open-frame PYBJ3-OM series in a surface-mount package, and the encapsulated PYBJ3-M series in a surface-mount package.

The PYB13 converter series offers 2:1 and 4:1 input voltage ranges, a single regulated output, and overvoltage, overcurrent, and short-circuit protection. Key specs include 1,500 VDC isolation and 125- to 600-mA output current. The operating temperature range is –40˚C to 85˚C. Target applications include convection-cooled equipment and applications, including microcontrollers, datacom, telecom, remote sensor systems, and portable electronics.