Top 10 DC/DC converters for railway and industrial

DC/DC converters for industrial applications and particularly railway systems must meet stringent requirements for a range of specifications. These include input/output voltage, electrical isolation, operating temperature, shock and vibration, and operational life.

To meet these requirements, DC/DC converter manufacturers continue to focus on designing devices that provide wider input voltage ranges to cover a broader range of applications, extended mean time between failures (MTBF) and higher efficiency. Many are also available in dual-output models. These devices are available in a variety of form factors, including brick types, chassis-mount, DIN-rail, and SIP and DIP packaging.

The global DC/DC converter market is forecast to reach $6.4 billion by 2027, up from $4.9 billion in 2022, growing at a compound annual growth rate of 5.1%, over the forecast period, according to a ResearchandMarkets report. The biggest demand drivers include industrial robots, industrial automation, telecommunications, healthcare and alternative energy sources.

Over the past year, DC/DC converter manufacturers have focused on wider voltage input ranges, higher efficiency and longer operational life while meeting and exceeding safety regulations in the railway and industrial segments. Here are the top 10 DC/DC converters for railway systems and industrial applications introduced over the past year.

Railway applications

Let’s start with ultra-wide–input devices that cover a variety of railway and industrial applications.

TDK Corp. recently introduced the 20-W–rated TDK-Lambda PYD20 series in a 2 × 1-inch footprint, housed in a silicone-potted plastic case for high resistance to shock and vibration. These DC/DC converters offer an ultra-wide 18:1 input of 8.5 to 160 VDC and are compatible with 12-V, 24-V, 48-V, 72-V and 110-VDC nominal system voltages. They can be used in a variety of industrial environments, including railroad rolling stock and trackside equipment, robotics, power generation and scientific research equipment.

These converters are available with 5-V, 12-V and 15-V single and ±12-V, ±15-V and ±24-V dual outputs. The dual models can be configured to provide a 20-W single 24-V, 30-V or 48-V output. They are trimmable using a resistor or an external voltage to compensate for voltage drops or to accommodate non-standard system voltages. They offer 3,000-VAC input-to-output isolation.

The converters offer efficiencies of up to 90%, with power losses minimized, allowing the products to operate with case temperatures of up to –40°C to 105°C, with derating at high temperatures and convection or forced-air cooling. Other features include overvoltage, overcurrent and overtemperature protection and remote on/off.

All models carry the CE and UKCA marks for the Low Voltage and RoHS Directives and are certified to the IEC/UL/CSA/EN 62368-1 safety standards. With external components, the PYD20 series has been tested or designed to meet EN 50155 (railroad standard for electronic equipment in railroad vehicles), EN 45545-2 (fire safety) and EN 61373 (railroad vibration standard).

The new 10-W PRC10W series from CUI Inc., a Bel group company, also features an ultra-wide 18:1 input range (8.5 to 160 VDC) and reinforced insulation. It offers up to 88% efficiency and a single or dual regulated output.

The series meets EN 50155 with an external circuit and is certified to IEC/BS EN/UL 62368-1, making it suited for railway and industrial applications. Safety approvals include CE, UKCA and UL/cUL. Isolation is 4,200 VDC.

Housed in a DIP package (31.8 × 20.3 × 12.7 mm/1.25 × 0.8 × 0.5 inches), these DC/DC converters can operate over a temperature range of –40°C to 100°C. They come with overvoltage, overcurrent, short-circuit and undervoltage lockout (UVLO) protection, as well as remote on/off control.

Another ultra-wide–input DC/DC converter is the 10-W EC7AW18-ECRT/EDRT series from Cincon Electronics Co. Ltd. The DC/DC converters offer an ultra-wide 16:1 input of 10 to 160 VDC in a module measuring 4 × 2.14 inches (101.6 × 54.4 mm).

The EC7AW18-ECRT/EDRT series is available in several configurations, including single outputs of 5, 12 and 15 VDC, as well as dual outputs of ±5, ±12 and ±15 VDC. It provides 3,000-VAC input-to-output isolation and a holdup time of 30 ms and features a remote on/off function. It meets the compliance standards for EN 50155, EN 61373 and EN 45545-2, making it suitable for railway applications. It also meets EN 50155 and EN 55032 standards for EMI and IEC/UL 62368-1 3rd edition. The series also passes the requirements of interruptions of voltage supply Class S3 and the voltage change-over Class C2 without an external capacitor.

The EC7AW18-ECRT/EDRT also offers high efficiency of up to 87% and operates over a wide operating case temperature range of –40°C to 100°C. It is suitable for use at high altitudes, reaching up to 5,000 meters maximum, and delivers an MTBF of up to 1,000 kilohours. Protection features include UVLO, overcurrent/overvoltage and continuous short-circuit protection.

The chassis-mount DC/DC converter targets a range of railway applications, such as information systems, entertainment systems, and CPUs and motor drivers for door-control systems. It can also be used in industrial/ITE applications, including automation equipment, test and measurement instruments and commercial equipment.

Aimed at meeting more stringent requirements in railway systems, Gaia Converter expanded its industrial-grade DC/DC converter line for rail applications with an upgraded ultra-wide–input portfolio, claiming “outstanding” MTBF performance, typically above 1,000 kilohours according to MIL-HDBK-217F (GB, 25°C), while meeting most demanding surge requirements.

These new converters include an input bus conditioner, a new device that can suppress extreme surges in railway environments and board-mount parts rated at 20 W (MGRI20), 40 W (MGRI40) and 80 W (MGRI80), with the added feature of 3-kVAC reinforced safety isolation rating to IEC 62368-1, Gaia said.

The new ultra-wide input range for each part is 12–160 VDC and includes 24-V, 48-V, 72-V, 96-V and 110-VDC nominal voltages to meet EN 50155 and other rail specifications, as well as common industrial applications. The input will also withstand 176 VDC for 100 ms to include the surge specified in rail standard NF-F 01-510 for 110-VDC nominal, as well as the RIA12 specification of 168 VDC for 20 ms for 48-VDC nominal.

Gaia said surges to 385 VDC for 20 ms (for the RIA12 spec) can be met with the additional input bus conditioner (FLHGI90), which also attenuates fast transients and provides reverse-polarity protection to ensure compliance with the EN 550121 EMC specification. Without the input bus conditioner, the parts can meet EN 55022 Class B EMI with a recommended external filter.

Other key features include 87% efficiency typical, a case operating temperature range from –40°C to 105°C without derating and integrated protection like overload, short-circuit, soft-start and input UVLO, with a trimmable threshold, to match all battery voltage standards. The devices are available in a fully potted low-profile metallic case: 35 × 30 × 10 mm for the 20-W part, 46 × 36 × 10 mm for the 40-W part and 50 × 44 × 12.9 mm for the 80-W part.

Another board-mount DC/DC converter line for railway applications is Recom Power’s RPA40-FR series in a through-pin package, measuring 50.8 × 25.4 × 10.2 mm (2 × 1 × 0.4 inches). Key specs for the 40-W device include an input range of 36–160 VDC (200 V/1 second); nominal input voltages of 72 V, 96 V and 110 V; and outputs of 5 V, 5.1 V, 12 V, 15 V, 24 V, ±12 V or ±15 V, with the single outputs trimmable by ±10% minimum and the 15- and 24-V models trimmable to 20%/–10%).

Recom said efficiency for the series peaks at 90% so that full-load output is possible to high ambient temperatures with natural convection cooling only. The advanced thermal design allows the operation to an ambient of 105°C with load derating and/or airflow.

No minimum load is required, and protection features include overtemperature, input undervoltage, output overcurrent and short-circuits. A control pin is also provided. They meet safety certifications to UL/EN/IEC 62368-1, EN 45545-2 and EN 50155, with an isolation rating of 3 kVAC/1 minute (reinforced). EN 55032 Class A EMC specification is met without external components, while Class B can be met with the addition of a simple filter, Recom said.

MTBF for the parts is 1.25 million hours, according to MIL-HDBK-217-F (GB/25°C), making them suitable for railways. They can also be used in general industrial application environments with surge voltages and high temperatures.

At the higher-power range, Bel Fuse Inc. recently expanded its RCM Series of converters with the RCM300 Series dual-output DC/DC converter for railway and transportation systems. The dual-output converters deliver 300 W at 24 V/–24 V.

“The two outputs are independently regulated, which provide tight and constant regulation even at extreme cross loads,” Bel Fuse said.

Designed for chassis mounting with a closed housing, the DC/DC converters, claiming low inrush current, extremely high efficiency and high power density, are suitable for railway traction and auxiliary converters, along with railway power-over-Ethernet applications. They are compliant to EN 50155, EN 50121-3-2 and AREMA electrical standards; EN 45545 and NFPA 130 fire and smoke standards; and IEC/EN 62368-1 and UL/CSA 62368-1 safety standards.

The RCM300 Series converters offer several feature options, such as an output ORing FET for redundant operation, interruption time of 10 ms (Class S2), shutdown input and an output voltage monitor controlling a relay. Protection features include overtemperature, overvoltage, overcurrent and overload. They measure 116 × 38 × 188.6 mm (4.57 × 1.5 × 4.43 inches).

Also at the higher power range is Traco Power’s 150-W TEP 150UIR and 200-W TEP 200UIR series of DC/DC converters in a fully encapsulated half-brick (2.3 × 2.3 × 0.5 inches) housing. These devices offer an ultra-wide input-voltage range of 14–160 VDC and output voltages of 5, 12, 15, 24 and 48 VDC; operate over a temperature range of –40°C to 105°C; and provide up to 3,000-VAC I/O isolation.

Other features include a dedicated holdup capacitor connection, a trim function, remote on/off and protection against short-circuits, overvoltage and overtemperature. They come with a three-year warranty.

The 12:1 input voltage range for the railway-certified TEP 150UIR and TEP 200UIR DC/DC converters target a range of nominal system voltages with a single design, Traco said. In addition, with dedicated holdup capacitor connections, the TEP 150UIR and TEP 200UIR can meet extended holdup-time requirements without the need for bulky input capacitors.

These converters are EN 50155–certified for rolling stock applications, EN 61373 for mechanical shock and vibration, EN 45545-2 for fire behavior and IEC/EN/UL 62368-1 for IT and general-purpose industrial applications.

Industrial DC/DC converters

Aimed at challenging environments, Flex Power Modules has expanded its PKB-D series of isolated eighth-brick (58.4 × 22.7 × 13.2 mm/2.29 × 0.89 × 0.52 inches) DC/DC converters with the launch of the 240-W PKB5213D, featuring a wide 18- to 60-V input range to include 24-V and 48-V nominal inputs and a fully regulated 12-V output rated at 20 A/240 W. The isolation is 2,250 VDC input to output. The series is safety-rated according to IEC/EN/UL 62368-1.

For power-dense and challenging environments like robotics, the thermally optimized PKB5213D achieves 94.6% efficiency at 24-V input and 50% load. It achieves an MTBF of 10.6 million hours at 40°C, according to Telcordia SR-332. Other features include pre-bias startup and a maximum hot-spot operating temperature of 125°C.

Protection features include input UVLO, output overvoltage, short-circuit and current limit as well as overtemperature. An optional baseplate is offered for conduction-cooled applications, and remote control is also available.

Aimed at a broad range of industrial applications, Absopulse Electronics Ltd. recently added the DCW 282-F1W Series to its portfolio of dual-output DC/DC converters with convection cooling. The design uses high-efficiency power-conversion topology to deliver up to 280-W output power. It has two fully independent regulated and isolated outputs, each providing any voltage between 5 V and 125 VDC.

The converters are available with either fixed or wide-range inputs. The fixed-input voltages include 24 VDC, 36 VDC, 48 VDC, 125 VDC or 250 VDC with wide input ranges. Models with wide input ranges of 20 V to 60 VDC or 65 V to 160 VDC are available. A 250-W DCH 282-F1W for dual-output power conversion with a 200- to 370-VDC input range is also available.

These converters are designed for compliance with EN62368-1 and equivalent safety standards. They operate at full spec over a 0°C to 50°C operating temperature range without derating and are available in extended temperature ranges. The converters are housed in a rugged chassis that measures 163 × 51 × 198 mm.

Protection features include 2,250-VDC input-to-output isolation, inrush current limiting, reverse polarity, overvoltage, overtemperature and short-circuit conditions. The input and output are filtered for low noise. The input meets EN55032 Class A with wide margins, the company said.

As wide-bandgap technologies like gallium nitride (GaN) gain further adoption in automotive and industrial applications, power manufacturers also need to address the voltages of the gate drivers for GaN-based devices.

One of the most recent to target gate-drive power is the MGN1 series of 1-W DC/DC converters from Murata Manufacturing Co. Ltd. These devices are small, surface-mount solutions with output voltages of 8 V, 12 V and 6/–3 V. The >200-kV/µs common-mode transient immunity makes them well-suited to the elevated switching speeds of GaN-based systems to ensure gate-driver signal integrity, Murata said, and due to their partial discharge performance, reliable operation is maintained in high-voltage conditions.

In addition, thanks to their ultra-low isolation capacitance of 2.5 pF (typical), the coupling of transients across the isolation barrier is minimized, which prevents signal distortion, and EMI system problems can be mitigated, Murata said.

These DC/DC converters support a continuous isolation barrier withstand voltage of 1.1 kV, with UL62368 conformance pending for 650-VDC basic insulation and 240-VAC reinforced insulation. They have 6.5-mm creepage and clearance figures. The operating temperature range is –40°C to 105°C. Other features include reverse-polarity and short-circuit protection.

Applications include EV fast-charging infrastructure, battery storage converters, smart-grid implementations, solar inverters, solid-state switching breakers, ICT and data centers, wind turbines and motor drives.