ACS-5151 – User’s Manual
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Chapter 4 Power Supply Description
Input protection and filtering
Reverse voltage protection
Input power reversal is a common error condition in power supply connection or installation in hostile
electrical environments. The ACS-5151 power supply will withstand reverse voltages up to 45V indefinitely. A
series Schottky diodes on the positive supply input line also protects the transient absorber diodes from
forward conducting in a reverse voltage condition. The reverse voltage protection diode is rated for a 9.0A
input current.
Over voltage protection
A high-speed automotive transient absorber diode (6600W 10/1000us) will clip all input transients below
acceptable limits. The input filters will also reduce the incoming energy of the over voltage pulse. The ACS-
5151 will tolerate a short-term over voltage condition up to 50V for a period of 100ms and a long-term supply
voltage up to 40VDC. A 5A rated thermal fuse mounted on the solder side of the board is connected in series
with the input. The normal maximum input current to the power supply is 8.1A assuming the input power is
65W.
Input filtering
Low radiated and conducted emissions are important when selecting power supplies for professional
embedded systems. All the power outputs from the onboard DC/DC converter subsystems are filtered using
power ferrites reducing emissions in the frequency range of 30 to 150MHz. The ACS-5151 will exceed the
requirements of the EC low voltage directives for CE compliance. An input filter specially dimensioned for the
ACS-5151 power supply ensures compatibility with EN-55022 class B or MIL-STD-461 requirements for
conducted and radiated emissions.
The frame of the module (as well as the chassis if it is conductive) may be connected to the ground of the
power supply input. Close B1 with a solder blob to make this connection next to the input connector of the
power supply.
Figure 12. Input filer of the ACS-5151
