K Series
DC-DC Converters >100 Watt
Rugged Environment
Edition 4/4.99
30/31
MELCHER
The Power Partners.
Threshold tolerances and hysteresis:
If
Ui is monitored, the internal input voltage is measured af-
ter the input filter. Consequently this voltage differs from the
voltage at the connector pins by the voltage drop
DUti
across the input filter. The threshold level of option V0 is ad-
justed during manufacture at
Io nom and TA = 25°C. The
value of
DUti depends upon the input voltage range (AK,
BK, ...), threshold level
Ut, temperature and input current.
The input current is a function of input voltage and output
power.
DUti
Uhi
UV low
UV
UV high
Ui
P
o
=
P
o
nom
P
o
=
0
P
o
=
0
Uti
P
o
=
P
o
nom
11023
Fig. 35
Definition of Uti,
U
ti and Uhi
3
5.1 V
4.875 V
0
U
i [V DC]
0
t
U
ti + Uhi
U
ti
Input voltage failure
Switch-on cycle
Input voltage sag
Switch-on cycle and subsequent
input voltage failure
U
V high
U
V low
U
V
0
V2
t
U
o1
0
U
V high
U
V low
U
V
0
V2
U
i
U
ti
4
Output voltage failure
0
U
V high
U
V low
U
V
3
U
ti + Uhi
t
low min
2
t
low min
2
t
low min
2
3
4
U
V high
U
V low
U
V
0
V3
t
3
t
low min
2
t
low min
2
3
t
h
1
2.0 V
t
h
1
4
3
4
t
low min
2
V3
5.1 V
4.875 V
0
U
o1
2.0 V
Input voltage monitoring
Output voltage monitoring
11010
t
Fig. 36
Relationship between Ui, Uo1, UV, IV and Uo1/Uo nom ver-
sus time.
1 VME request: minimum 4 ms
2 tlow min = 40...200 ms, typically 80 ms
3 UV level not defined at Uo1 < 2.0 V
4 The V signal drops simultaneously with the output voltage. If the
pull-up resistor
RP is connected to Vo1+. The V signal remains
high if
RP is connected to an external source.