psb243-7ir Power-One, psb243-7ir Datasheet - Page 5

• Manufacturer Part Number: psb243-7ir
• Description: Psb Series Extended Positive Switching Regulators Rugged
• Manufacturer: Power-One

REV. OCT 17, 2003
I
Fig. 3
Dynamic load regulation.
Thermal Considerations
When a switching regulator is located in free, quasi-sta-
tionary air (convection cooling) at a temperature T
and is operated at its nominal output current I
case temperature T
phase, measured at the Measuring point of case tempera-
ture T
Under practical operating conditions, the ambient tem-
perature T
ures (heat sink, fan, etc.) are taken to ensure that the case
temperature T
95°C.
With an input voltage above 80 V (up to 144 V) or an out-
put current higher than I
allowed temperatures are reduced according to fig.: Out-
put current derating versus temperature. A check of the
case temperature at worst case conditions (highest input
voltage and highest output current of the application)
against the applicable curve of the figure ensures correct
operation of the system.
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
Fig. 4
Output current derating versus temperature
V
o
1
0
o
/ I
0
I
o
o nom
T
T
/ I
A min
C min
o max
C
V od
(see: Mechanical Data ).
46
A
50
may exceed 71°C, provided additional meas-
C
V
i
does not exceed its maximum value of
> 80 V
10 µs
t
d
60
C
will be about 95°C after the warm-up
o nom
70
71
V
D V
i
o I
(up to I
80 V
80
V od
83
V
i
o max
V
> 80 V
90
i
10 µs
) the maximum
80 V
t
d
100
o nom
A
T
= 71°C
A
, T
T
T
, the
[˚C]
Page 5 of 13
D V
A max
C max
05010
C
o I
t
t
Positive Switching Regulators (Rugged)
Output Protection
A voltage suppressor diode which in worst case conditions
fails into a short circuit, (or a thyristor crowbar, option C)
protects the output against an internally generated over-
voltage. Such an overvoltage could occur due to a failure
of either the control circuit or the switching transistor. The
output protection is not designed to withstand externally
applied overvoltages. The user should ensure that sys-
tems with Power-One power supplies, in the event of a
failure, do not result in an unsafe condition (fail-safe).
Parallel and Series Connection
Outputs of equal nominal voltages can be parallel-con-
nected. However, the use of a single unit with higher out-
put power, because of its power dissipation, is always a
better solution.
In parallel-connected operation, one or several outputs
may operate continuously at their current limit knee-point
which will cause an increase of the heat generation. Con-
sequently, the max. ambient temperature value should be
reduced by 10 K.
Outputs can be series-connected with any other module.
In series-connection the maximum output current is limited
by the lowest current limitation. Electrically separated
source voltages are needed for each module!
Temperature dependent output current limitation
response I
These switching regulators withstand a continuous input
voltage of up to 144 V DC (120 V +20%) with surges up to
156 V for 2 s. They also comply with LES-DB standard for
V
I
range for an input voltage up to 80 V, or over the whole in-
put voltage range at a reduced maximum ambient tem-
perature of T
For operation at T
voltage between 80 and 144 V the internal thermistor
(PTC) starts to reduce the output current limitation value I
L
duction of I
The fig.: Typical temperature dependent output current
limitation response I
continuous operation with different ambient and case tem-
peratures. Operation at higher ambient temperatures T
possible, provided that the specified case temperature
T
fan, etc.).
o max
. Under the most extreme conditions this results in a re-
C max
N
= 110 V.
is continuously available over the entire temperature
is not exceeded (short term operation, heat sink,
PSB Series Extended Data Sheet
o L
o L
A max
by 1 A from I
= 46°C.
A
o L
= 46 to 71°C together with an input
shows the minimum I
o max
to I
o nom
.
o L
value for
A
is
o