FEB 17, 2006 revised to JUL 25, 2006 Page 8 of 10 www.power-one.com\
HLS Series DC-DC Converter Data Sheet
48 VDC Input, 30 & 40 Amp Half-Bricks
Safety Considerations
The HLS Series converters feature 1500 Volt DC
isolation from input to output. The input to output DC
resistance is greater than 10MΩ. These converters
are provided with Basic insulation between input and
output circuits according to all IEC60950 based
standards. Nevertheless, if the system using the
converter needs to receive safety agency approval,
certain rules must be followed in the design of the
system. In particular, all of the creepage and
clearance requirements of the end-use safety
requirements must be observed. These documents
include UL60950, CSA60950-00 and EN60950,
although other additional requirements may be
needed for user’s specific applications.
The HLS Series converters have no internal fuse.
An external fuse must be provided to protect the
system from catastrophic failure, as illustrated in
Figure 6. The fuse with a rating not greater than
10 A is recommended. The user can select a lower
rating fuse based upon the highest inrush transient
at the maximum input voltage and the maximum
input current of the converter at the minimum input
voltage. Both input traces and the chassis ground
trace (if applicable) must be capable of conducting a
current of 1.5 times the value of the fuse without
opening. The fuse must not be placed in the
grounded input line, if any.
In order for the output of the HLS Series converter to
be considered as SELV (Safety Extra Low Voltage)
or TNV-1, according to all IEC60950 based
standards, one of the following requirements must be
met in the system design:
• If the voltage source feeding the module is SELV
or TNV-2, the output of the converter may be
grounded or ungrounded.
• If the voltage source feeding the module is ELV,
the output of the converter may be considered
SELV only if the output is grounded per the
requirements of the standard.
• If the voltage source feeding the module is a
Hazardous Voltage Secondary Circuit, the
voltage source feeding the module must be
provided with at least Basic insulation between
the source to the converter and any hazardous
voltages. The entire system, including the HLS
converter, must pass a dielectric withstand test
for Reinforced insulation. Design of this type of
system requires expert engineering and
understanding of the overall safety requirements
and should be performed by qualified personnel.
Thermal Considerations
The HLS Series converters are designed for natural
or forced convection cooling. The maximum
allowable output power of the converters is
determined by meeting the derating criteria of all
electronic components used in the power supplies.
An example of the derating criteria for the
semiconductor junction temperature is not to exceed
120 °C to provide reliable, long-term operation of the
converters.
The graphs in Figures 10-14 show the maximum
output current of the HLS Series converters at
different ambient temperatures under both natural
and forced (longitudinal airflow direction, from pin 1
to pin 4) convection. This is further illustrated in Fig.
9 as arrow ‘A’. As an example, from Figure 10, the
HLS30ZG operating at 55 °C can deliver up to 22 A
reliably with 100 LFM forced air, while up to 25 A
reliably with 200 LFM forced air.
Figure 9. HLS Forced Airflow Directions (A, B, C)
Airflow directions ‘A’ and ‘C’ should be considered
equivalent in terms of the cooling effectiveness each
provides. Direction ‘B’ can offer a marginal (<
3.5%)
power capability improvement over that offered by ‘A’
or ‘C’. This characteristic is demonstrated in Fig. 15.
Note:
Figure 15 was established with Vin = 48 VDC, and figures 10-14
at Vin = 52 VDC. The resulting small difference in converter
efficiency introduces an error term that prevents accurate
correlation directly between figures 10 and 15.)
Pin side down
B
C
