LS4000 datasheet(9/27 Pages) POWER-ONE

9 / 27 page

Cassette Style

100 Watt AC-DC Converters

S Series PFC

Edition 01/01.2001

9/27

Output Voltage Regulation of Double Output Modules

Output 1 is under normal conditions regulated to

Uo1 nom,

independent of the output currents.

Uo2 is dependent upon the load distribution. If both outputs

are loaded with more than 10% of

Io nom, the deviation of

Uo2 remains within

±5% of the value of U

o1. The following 3

ﬁgures show the regulation with varying load distribution. If

Io1 = Io2 or the two outputs are connected in series, the de-

viation of

Uo2 remains within

±1% of the value of U

o1 pro-

vided that a total load of more than 10% of

Io nom is applied.

Two outputs of a single S 5000 module connected in paral-

lel will behave like the output of a S 4000 module; the paral-

leled output is fully regulated. No precautions are neces-

sary in using the R-input and the test sockets.

Uo nom

0.98

0.5

1.0

Io1

IoL

Io nom

05001

Fig. 9

Uo1 vs. Io1 (typ.) of single output units

Thermal Considerations

If a converter is located in free, quasi-stationary air (con-

vection cooling) at the indicated maximum ambient tem-

perature

TA max (see table: Temperature specifications) and

is operated at its nominal input voltage and output power,

the temperature measured at the

Measuring point of case

temperature TC (see: Mechanical Data) will approach the

indicated value

TC max after the warm-up phase. However,

the relationship between

TA and TC depends heavily on the

conditions of operation and integration into a system. The

thermal conditions are influenced by input voltage, output

current, airflow and temperature of surrounding compo-

nents and surfaces.

TA max is therefore, contrary to TC max,

an indicative value only.

Caution: The installer must ensure that under all operat-

ing conditions

TC remains within the limits stated in the

table:

Temperature specifications.

Notes: Sufficient forced cooling or an additional heat sink

allows

TA to be higher than 71

°C (e.g. 85°C) if T

C max is not

exceeded.

For -7 or -9 units at an ambient temperature

TA of 85

°C with

only convection cooling, the maximum permissible current

for each output is approx. 40% of its nominal value as per

figure.

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

100

Io/Io nom

TA [°C]

0.9

1.0

Forced cooling

TA min

TC max

Convection cooling

Fig. 8

Output current derating versus temperature for -7 and -9

units.

Thermal Protection

A temperature sensor generates an internal inhibit signal

which disables the outputs if the case temperature exceeds

TC max. The outputs are automatically re-enabled if the tem-

perature drops below this limit.

It is recommended that continuous operation under simul-

taneous extreme worst case conditions of the following

three parameters be avoided: Minimum input voltage,

maximum output power and maximum temperature.

Output Protection

Each output is protected against overvoltage which could

occur due to a failure of the control circuit by means of a

voltage suppressor diode which, under worst case condi-

tions, may become a short circuit. The suppressor diodes

are not designed to withstand externally applied over-

voltages. Overload at any of the two outputs will cause a

shut-down of both outputs. A red LED indicates the over-

load condition.

Parallel or Series Connection of Units

Single or double output units with equal nominal output volt-

age can be connected in parallel without any precautions

using option T.

With option T (current sharing), all units share the current

approximately equally.

Single output units and/or main and second outputs of dou-

ble output units can be connected in series with any other

(similar) output.

Note:

– Parallel connection of double output units should always

include both, main and second output to maintain good

regulation of both outputs.

– Not more than 5 units should be connected in parallel.

– Series connection of second outputs without involving

their main outputs should be avoided as regulation may

be poor.

– The maximum output current is limited by the output with

the lowest current limitation if several outputs are con-

nected in series.

Output Voltage Regulation of Single or Double Output

Modules with Outputs 1 and 2 Connected in Series

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