ST UC2842B - Page 12

D95IN354
+
R
BIAS
OSC
C
R
+
-
+
-
EA
R
2R
R
S
Q
8
4
2
1
5
1mA
1V
+
-
5V
ref
1MΩ
Figure 24: Soft-Start Circuit
D95IN355
+
R
BIAS
OSC
C
R
+
-
+
-
EA
R
2R
R
S
Q
8
4
2
1
5
1mA
1V
+
-
5V
ref
R2
R1
V
Clamp
+
-
Comp/Latch
7
R
S
V
CC
Q1
V
in
7
6
5
BC109
V
CLAMP
= ·
R
1
R
1
+ R
2
where 0 <V
CLAMP
<1V I
pk(max)
=
V
CLAMP
R
S
Figure 25: Soft-Start and Error Amplifier Output Duty Cycle Clamp.
UC2842B/3B/4B/5B - UC3842B/3B/4B/5B
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