PU1 - Power Supply Unit, 110 VDC, 75 W (Product Discontinued)

The 3U 12HP power supply unit PU1 is a plug-in device for 19" systems (e.g. VMEbus, CompactPCI) and is especially designed for railway computer systems, being fully compliant with EN 50155.

The 1.5 kV (effective) optically isolated PSU comes with a nominal input voltage of 110 VDC with a wide input range of 77..137.5 V (max. input voltage range 66..154 V according to EN50155) and a single output of 5 V at 75 W. It works up to +85°C without derating, delivering a thermal warning at over-temperature andswitching off at +95°C.

The PSU supports an error signal (5 ms hold-up time), reverse-connect protection, permanent short-circuit protection, voltage control, synchronization, voltage in fail (ViF) and voltage out fail (VoF) as well as remote on/off.

The subassembly is immersion-painted und partially cast, and components are secured against vibration. The thermal stress is extremely low due to integrated heat sinks and diversion of dissipated heat over the mounting surface.


  • 19" rack mountable (VMEbus, CompactPCI)
  • 3U, 12 HP
  • Input 110 VDC nom. (77..137.5 V)
  • Max. input voltage range 66..154 V (according to EN 50155)
  • Output 5.1 V
  • Power 75 W
  • H15 DIN 41612 plug connector (front and rear)
  • -40 °C to +85 °C without derating
  • Conformal coating
  • Complies with EN 50155 (railways)


  • Standard Euro rack size 19"
  • Integrated heat sink for extremely low thermal stress to temperature sensitive components
  • Glued parts for better vibration resistance
  • Overtemperature and overvoltage shutdown
  • Short circuit protection
  • Remote on/off
  • LEDs: green LED indicates correct input voltage, yellow LED indicates operating mode
  • Fixed switching frequency 200kHz
  • Reverse polarity protection by internal protector
  • Thermal Warning (TW)
    • Operating criteria: Overtemperature shutdown -5K (Risk of overtemperature exists.)
    • Output TW: Output with NPN transistor, emitter connected with V out-; max. current 30mA
  • Hold-up Time
    • According to EN 50155 Class S2 for P out 75W
  • Supply Fail (FAL)
    • Output FAL: Isolated optocoupler output with NPN transistor
    • Current: 5mA
    • Voltage max.: 5V
    • Pins: Open collector FAL, emitter FAL connected to V out-
    • Isolation: FAL-V in: 1.500 Vrms
  • Sense (S)
    • Provides compensation of voltage drops (max. 0.2V each line) between power supply and load
    • Pins S+ and S- of converter must be connected to load
  • Shutdown interrupt (SD-INT)
    • SD-INT in: 24V
    • SD-INT out current: 5mA
    • SD-INT out voltage: 5V
    • SD-INT out pins: Collector pull-up resistor 10K to V out+
    • SD-INT out isolation: SD-INT in to SD-INT out: 1.500 Vrms
Input Characteristics
  • Nominal voltage input: 110V DC
  • Wide input range: 0.7 x nominal voltage < nominal voltage < 1.25 x nominal voltage (according to EN 50155)
    • 77..137.5 VDC
  • Max. input voltage range: 0.6 x nominal voltage < nominal voltage < 1.4 x nominal voltage with full functionality for 0.1 s, no damage for 1 s (according to EN 50155)
    • 66..154 VDC
  • Voltage on threshold: 1.1V
  • No load input current: 15mA
Output Characteristics
  • Output: 5V/75W
  • Accuracy: ±0.5%
  • Voltage deviation: 12%
  • Rise time: 80ms
  • Overvoltage protection: 1.2V
  • Overcurrent protection: 1.08A min., 1.15A max.
  • Overtemperature shutdown: 101°C min., 105°C typ., 107°C max.
Input and output via DIN 41612 plug connector, type H15
Electrical Specifications
  • Isolation
    • Input/output: 1500V eff
    • Input/case: 1500V eff
    • Output/case: 500V eff
  • MTBF: tbd. @ 50°C (derived from MIL-HDBK-217F)
Mechanical Specifications
  • Dimensions: 3U, 12HP, 128.4mm height
  • Weight: ca. 1395g
Environmental Specifications
  • Temperature range (operation): -40..+85°C
  • Temperature range (storage): -40..+105°C
  • Shock: according to IEC 68-2-27
  • Continuous shock: according to IEC 68-2-29
  • Vibration: according to IEC 68-2-6
  • Protection
    • Class of protection: Class I, EN 60950
    • Degree of protection: IP20 (inserted in rack), DIN 40050 (IEC 529)
  • Pollution degree: 2 (EN 60950)