Regulating Pulse Width Modulator
Error Amplifier Section
15 +VIN
Q3
Q1
INV.
INPUT
1
N.I. 2
INPUT
200 µA
Q2
Q4
100 µA
To PWM
COMPARATOR
5.8 V 30 Ω
9 COMP
Figure 5 · Error Amplifier
80
60
40
20
1
2
0
10
CP
RZ
RZ = 20k
FREQUENCY - Hz
Figure 6 · Error Amplifier Open-Loop Frequency
Response
Output Section
+VIN
Q5
Q4
+VREF
Q1
Q2
Q6
Q3
13 +VC
Q7
Q9
Q10
5k
11
14
OUTPUT
Q8
Q11
2k
Q6 OMITTED
in SG1527A
5k
10k
10k
CLOCK F/F
PWM
Figure 7 · Output Circuit (½ circuit shown)
4
VIN = 20 V
TA = 25°C
3
2
SOURCE SAT. VC - VOH
1
SINK SAT. VOL
0
Figure 8 · Output Saturation Characteristics
8