JUN 06, 2006 revised to JUL 25, 2006

Page 10 of 12

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HHS60 DC-DC Series Data Sheet

48VDC Input, 60 Amp Half-Brick Converter

Optional Positive-Trim (–T, P/N suffix)

The trim feature allows the user to adjust the output

voltage from its nominal value.

The HHS60 positive-trim (-T) models trim up with a

resistor from the Trim (#7) pin to the +Sense (#8) pin

and trims down with a resistor from the Trim pin to

the –Sense (#6) pin as shown in the Figure 17.

Figure 17

. HHS60 Series Positive Trim Schematic

The equations below determine the trim resistor

value required to achieve a ΔV change in the output

voltage.

100

Δ%

Vo*(100+

Δ%)

(100+2*

Δ%)

1.225*

Δ%

Δ%

where ΔV% is the output voltage change expressed

in percent of the nominal output voltage, Vout.

Notes:

1.

When the output voltage is trimmed up, the output power

from the converter must not exceed its maximum rating. The

power is determined by measuring the output voltage on the

output pins, and multiplying it by the output current.

2.

In order to avoid creating apparent load regulation

degradation, it is important that the trim resistors are

connected directly to the remote sense pins, and not to the

load or to traces going to the load.

3.

The output voltage increase can be accomplished by either

the trim or by the remote sense or by the combination of

both. In any case the absolute maximum output voltage

increase shall not exceed the limits defined within the

“Features” section above.

4.

Either Rup or Rdown should be used to adjust the output

voltage according to the equations above. If both Rup and

Rdown are used simultaneously, they will form a resistive

divider and the equations above will not apply

Safety Considerations

The HHS60 Series converters feature 1500 VDC

isolation from input to output. The input to output

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 or additional requirements may be

needed for specific applications.

The HHS60 Series converters have no internal fuse.

An external fuse must be provided to protect the

system from catastrophic failure, as illustrated in

figure 15. Refer to the “Input Fuse Selection for

DC/DC converters” application note on www.power-

one.com for proper selection of the input fuse. 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 HHS60 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