TK75001 Datasheet, PDF (12/13 Pages) TOKO, Inc – PWM CONTROLLER

TK75001
APPLICATION INFORMATION (CONT.)
TK75001 OFF-LINE APPLICATION EXAMPLE
Figure 8 shows an off-line, universal input, 12 W power supply. The TK75001 is the controller IC for a flyback converter
with self-bias and constant-frequency, current-mode control. The TK75001 drives the MOSFET directly to switch the
flyback transformer. Feedback is accomplished by means of a TL431, configured as a secondary side error amplifier and
voltage reference, driving an opto-coupler for isolation.
RB155
2A
85-265 VAC
47-440 Hz
1 mH
RM4
1.5 mH
0.2 A
+
22 µF
400 V
16 Ω
KCO17L
1M
0.25 W
FMMTA42
1M
0.25 W
0.1 µF
400 V
24 k
0.5 W
FMMTA42
0.01 µF
FMMT2222A
1N4148
0.001 µF
400 V
RM6-N67
AL250
n1
n3
6CWF20F
100
0.5 W
n2
330 pF
100 V
+
330 µF
16 V
FERRITE
BEAD
+
330 µF
16 V
+
82µF
25V
12 V
1A
620
+
82 µF
25 V
VCC
CT
TK75001
220 pF
DRV
FB
GND
1.8 k
BYV26CPH
n1 = 31, AWG28
n2 = 6, triple insulated, AWG24
n3 = 7, AWG34
15
IRFRC20
0.047 µF
220 pF
50 V
1.2
0.25 W
220
470
CNY17-2
4.75 k
1%
470
4.7 k ^{0.01 µF}
TL431
1.24 k
1%
FIGURE 8: OFF-LINE, UNIVERSAL INPUT, 12-WATT POWER SUPPLY
Page 12
January 1999 TOKO, Inc.