TL594
V
ref
6
5
R
C
T
Master
T
R
T
C
T
V
CC
R
S
12
V
ref
V > 40V
in
1N975A
V = 39V
Z
5.0V
Ref
6
5
R
C
T
Slave
(Additional
Circuits)
270
Gnd
7
T
Figure 19. Slaving Two or More Control Circuits
Figure 20. Operation with Vin > 40 V Using
External Zener
+V = 8.0V to 20V
in
12
+V = 28V
O
I
O
= 0.2A
1N4934
47
1
V
T
CC
1
+
−
8
22
k
2
Tip
32
C
1
L
1.0M
33k
3
1
+
50
35V
TL594
Comp
−
+
50
25V
0.01
0.01
15
16
11
Tip
32
C
4.7k
2
+
50
35V
+
1
2
OC
V
DT
C
R
T
Gnd
7
E
E
REF
T
1.0
47
1N4934
13 14
4
5
6
9
10
+
240
4.7k
4.7k
10
10k
15k
0.001
All capacitors in mF
Figure 21. Pulse Width Modulated Push−Pull Converter
Test
Conditions
= 10 V to 40 V
Results
14 mV 0.28%
3.0 mV 0.06%
65 mVpp P.A.R.D.
1.6 A
L1 − 3.5 mH @ 0.3 A
T1 − Primary: 20T C.T. #28 AWG
T1 − Secondary: 12OT C.T. #36 AWG
T1 − Core: Ferroxcube 1408P−L00−3CB
Line Regulation
Load Regulation
Output Ripple
V
in
V
in
V
in
V
in
V
in
= 28 V, I = 1.0 mA to 1.0 A
O
= 28 V, I = 1.0 A
O
Short Circuit Current
Efficiency
= 28 V, R = 0.1 W
L
= 28 V, I = 1.0 A
71%
O
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