Safety Specification
General information.
Isolated DC/DC converters.
Ericsson Power Modules DC/DC converters and DC/DC
regulators are designed in accordance with safety standards
IEC/EN/UL 60 950, Safety of Information Technology Equipment.
It is recommended that a fast blow fuse with a rating
twice the maximum input current per selected product
be used at the input of each DC/DC converter. If an input filter
is used in the circuit the fuse should be placed in front of the
input filter.
In the rare event of a component problem in the input filter
or in the DC/DC converter that imposes a short circuit on the
input source, this fuse will provide the following functions:
IEC/EN/UL60950 contains requirements to prevent injury or
damage due to the following hazards:
• Electrical shock
• Energy hazards
• Fire
• Mechanical and heat hazards
• Radiation hazards
• Chemical hazards
• Isolate the faulty DC/DC converter from the input power
source so as not to affect the operation of other parts of the
system.
• Protect the distribution wiring from excessive current and
power loss thus preventing hazardous overheating.
On-board DC-DC converters are defined as component power
supplies. As components they cannot fully comply with the
provisions of any Safety requirements without “Conditions of
Acceptability”. It is the responsibility of the installer to ensure
that the final product housing these components complies
with the requirements of all applicable Safety standards and
Directives for the final product.
The galvanic isolation is verified in an electric strength test.
The test voltage (VISO) between input and output is 1500 Vdc
or 2250 Vdc for 60 seconds (refer to product specification).
Leakage current is less than 1µA at nominal input voltage.
24 V dc systems.
The input voltage to the DC/DC converter is SELV (Safety
Extra Low Voltage) and the output remains SELV under normal
and abnormal operating conditions.
Component power supplies for general use should comply
with the requirements in IEC60950, EN60950 and UL60950
“Safety of information technology equipment”.
48 and 60 V dc systems.
If the input voltage to Ericsson Power Modules DC/DC
converter is 75 V dc or less, then the output remains SELV
(Safety Extra Low Voltage) under normal and abnormal
operating conditions.
There are other more product related standards, e.g.
IEC61204-7 “Safety standard for power supplies",
IEEE802.3af “Ethernet LAN/MAN Data terminal equipment
power”, and ETS300132-2 “Power supply interface at the
input to telecommunications equipment; part 2: DC”,
but all of these standards are based on IEC/EN/UL60950 with
regards to safety.
Single fault testing in the input power supply circuit should
be performed with the DC/DC converter connected to
demonstrate that the input voltage does not exceed 75 V dc.
If the input power source circuit is a DC power system, the
source may be treated as a TNV2 circuit and testing has
demonstrated compliance with SELV limits and isolation
requirements equivalent to Basic Insulation in accordance with
IEC/EN/UL 60 950.
Ericsson Power Modules DC/DC converters and DC/DC
regulators are UL 60 950 recognized and certified in
accordance with EN 60 950.
The flammability rating for all construction parts of the
products meets UL 94V-0.
Non-isolated DC/DC regulators.
The products should be installed in the end-use equipment, in
accordance with the requirements of the ultimate application.
Normally the output of the DC/DC converter is considered as
SELV (Safety Extra Low Voltage) and the input source must be
isolated by minimum Double or Reinforced Insulation from
the primary circuit (AC mains) in accordance with
IEC/EN/UL 60 950.
The input voltage to the DC/DC regulator is SELV (Safety
Extra Low Voltage) and the output remains SELV under normal
and abnormal operating conditions.
It is recommended that a slow blow fuse with a rating
twice the maximum input current per selected product
be used at the input of each DC/DC regulator.
EN/LZT 146 033 R1D © Ericsson Power Modules, June 2004
PKB 4000 Datasheet
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