K Series Data Sheet
150 Watt DC-DC and AC-DC Converters
Functional Description
The input voltage is fed via an input fuse, an input filter, a bridge
rectifier (LK), and an inrush current limiter to the input capacitor.
This capacitor sources a single transistor forward converter.
Each output is powered by a separate secondary winding of the
main transformer. The resultant voltages are rectified and their
ripple smoothed by a power choke and output filter. The control
logic senses the main output voltage
V
o1 and generates, with
respect to the maximum admissible output currents, the control
signal for the primary switching transistor.
The second output of double-output models is controlled by the
main output but has independent current limiting. If the main output
is driven into current limitation, the second output voltage will fall as
well and vice versa.
P
26
N
5
03057-082605
16 R
Y
Vi+
28
18 i
20 D/V
Control circuit
22 T
12 S+
4
Output
filter
6
Vo+
2
1
Input filter
4
Forward converter
(approx. 120 kHz)
Y
8
Vo–
10
4
Fuse
Y
3
P
5
30
Vi– 32
Y
14 S–
24
Fig. 1
Block diagram of single output converters AK - LK1000
P
–
+
03058-082605
16 R
N
5
26
Vi+ 28
Input filter
1
4
Y
2
18 i
20 D
Control circuit
22 T
Forward converter
(approx. 110 kHz)
Y
Output 1
filter
12 Vo1+
14 Vo1–
4
6
Vo2+
4
3
Y
Y
P
5
Vi–
30
32
Y
Y
Output 2
filter
8
10
Vo2–
24
–
+
Fig. 2
Block diagram of symmetrical double output converters AK - LK2000
1
2
Transient suppressor (VDR) in CK, DK, EK, FK, LK models
Suppressor diode in AK, BK, CK, FK models
3
4
5
Inrush current limiter in CK, DK, EK, LK (NTC resistor or option E circuit)
Bridge rectifier (LK only)
LK models
APR 26, 2006 revised to MAY 15, 2006
Page 4 of 34
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