UC3842B, UC3843B, UC2842B, UC2843B, NCV3843BV
V
CC
V
in
V
CC
V
ref
8(14)
R
T
2.5V
R
Oscillator
+ 1.0mA
2R
Error
Amplifier
R
1.0V
Current Sense
Comparator
Gnd
5(9)
7(12)
Reference
Regulator
R
Internal
Bias
3.6V
+
-
V
ref
UVLO
36V
V
CC
UVLO
+
-
(See
Text)
V
C
7(11)
Output
6(10)
Q1
C
T
4(7)
S
R
Q
PWM
Latch
Voltage
Feedback
Input 2(3)
Output/
Compensation 1(1)
Power Ground
5(8)
Current Sense Input
3(5)
R
S
Pin numbers adjacent to terminals are for the 8-pin dual-in-line package.
Pin numbers in parenthesis are for the D suffix SO-14 package.
= Sink Only Positive True Logic
Figure 18. Representative Block Diagram
Capacitor C
T
Latch
Set" Input
Output/
Compensation
Current Sense
Input
Latch
Reset" Input
Output
Large R
T
/Small C
T
Small R
T
/Large C
T
Figure 19. Timing Diagram
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