QLS30 Series – 30A Quarter-Brick DC/DC Converter

48V Input

Data Sheet

1.8V, 1.5V, 1.2V Output

REV. 10/01

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 QLS30 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 QLS30 converter, must pass a

dielectric

withstand

test

for

reinforced

insulation.

Design of this type of systems

requires

expert

engineering

and

understanding

of

the

overall

safety

requirements and should be performed by

qualified personnel.

Thermal Considerations

The QLS30 series converters are designed for

both natural and forced convection cooling. The

maximum allowable output current 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.

Please contact Power-One for more derating

criteria for other components. The graphs in

Figures 10-12 show the maximum output current

of the QLS30 series converters at different

ambient temperatures under both natural and

forced (longitudinal airflow direction, from pin 1 to

pin 3) convection. As an example, from Figure

11, the QLS30ZA operating at 55

°C can deliver

up to 25A reliably with 100LFM forced air, while

up to 29A reliably with 200LFM forced air.

0

5

10

15

20

25

30

35

25

30

35

40

45

50

55

60

65

70

75

80

85

Ambient Temperature (C)

0

100LFM

200LFM

300LFM

400LFM

Fig.10 QLS30ZB (1.8V) derating curves

0

5

10

15

20

25

30

35

25

30

35

40

45

50

55

60

65

70

75

80

Ambient Temperature (C)

0

100LFM

200LFM

300LFM

400LFM

Fig.11 QLS30ZA (1.5V) derating curves

0

5

10

15

20

25

30

35

25

30

35

40

45

50

55

60

65

70

75

80

85

Ambient Temperature (C)

0

100LF

M

200LF

Fig.12 QLS30ZY (1.2V) derating curves

.