MC34023 MC33023
Figure 18. Representative Block Diagram
V
V
in
CC
16
15
Reference
Regulator
V
ref
V
V
CC
CC
4
5
UVLO
Clock
9.2 V
13
V
V
4.2 V
ref
UVLO
Oscillator
C
R
T
14
6
7
C
T
Output
12
R
PWM
Comparator
Q
Power Ground
1.25 V
Ramp
S
PWM Latch
Error Amp Output
3
2
Current
Limit
Error
Amp
+
11
Noninverting Input
Inverting Input
Current Limit Reference
9.0
µA
1
8
9
Current Limit/Shutdown
Soft–Start
0.5 V
Soft–Start Latch
R
S
1.4 V
C
SS
Q
Shutdown
10
Ground
Figure 19. Current Limit Operating Waveforms
C
T
Clock
Soft–Start
Error Amp Output
Ramp
PWM
Comparator
Output
7
MOTOROLA ANALOG IC DEVICE DATA