11:1 input dc-dc converter for railways meets EN50155

RED40-72xxxU converter will work over 14 – 160Vdc (11:1 range) and comes in a 2 x 1in (~25 x 50mm) footprint package.

“Using just one dc-dc converter model for various supply voltages – 24, 28, 36, 48, 72, 96 or 110Vdc – in different regions avoids multiple input voltage models in the warehouse,” according to Luso Electronics, which is stocking the parts.

Devices in another part of the same range, called RED40-36xxxU, work over 9 – 75Vdc (8:1) for running from nominal supplies of 12, 24, 36 or 48V.

The series includes single output and dual output models of 5, 5.1, 12, 15, 24, ±12, ±15Vdc, and a single resistor can be used to trim this value ±10% – and to +20% in some models.

Input to output isolation is 3kVdc (2,250V input or output-to-case).

In some versions, a resistor-programmable pin allows the built-in under-voltage lock-out to be set to an appropriate value for the expected supply.

In other versions, this same pin is used to provide an output voltage hold-up (‘Bus’ in circuit left) through input perturbation to meet EN 50155.

“The Bus pin provides a stable and fixed charging voltage which allows the usage of just one hold-up capacitor for any input voltages, and additionally reduces the in-rush current during the start-up phase,” according to Luso. The data sheet does not describe how to use this function, and simply states: “For further information, please contact P-Duke.

Remote on-off is another option.

Protections include: over-current, output short-circuit, output over-voltage protection and over-temperature. An external input line fuse is compulsory, and both type and rating differ between -36 and -72 series – check the data sheet.

Operation is up to 5km altitude and nominally over -40 to +105°C, although options with heatsinks of various sizes are required in some conditions to achieve EN 50155 OT4 or ST1 operating temperatures, for example. Some of the heatsinks increase the width of the footprint and all increase height.

As well as to EN 50155, there are certifications or pending certifications to IEC/EN/UL 62368-1 and EN 45545-2. Shock and vibration levels are compliant with EN 61373 and MIL-STD-810F.

Warranty is three years, and use is foreseen in rolling stock, transportation and construction machinery.

The Luso RED40U product page is here, and the data sheet here.

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