ml4812 Fairchild Semiconductor, ml4812 Datasheet - Page 6

• Manufacturer Part Number: ml4812
• Description: Power Factor Correction Pfc Controller
• Manufacturer: Fairchild Semiconductor

ML4812
Functional Description
Oscillator
6
EXTERNAL
CLOCK
RAMP VALLEY
RAMP PEAK
R SYNC
C SYNC
CLOCK
Figure 1. Oscillator Block Diagram
V(C T )
I SET
R T
C T
10
16
9
SYNC
R T
C T
8.4mA
t D
Q
1
I SET
5.6V
Q
2
+
-
Figure 3. Output Saturation Voltage vs. Output Current
Figure 2. Oscillator Timing Resistance vs. Frequency
10
8
5
3
2
1
10
10nF
20nF
15
14
13
3
2
1
0
0
SOURCE SATURATION
V CC
LOAD TO GROUND
SINK SATURATION
OSCILLATOR FREQUENCY (kHz)
LOAD TO V CC
5nF
200
OUTPUT CURRENT (mA)
2nF
100
400
PRODUCT SPECIFICATION
1nF
80 s PULSED LOAD
90%
120Hz RATE
V CC = 15V
REV. 1.0.4 5/31/01
600
1000
GND
85%
80%
70%
800