UC3844B, UC3845B, UC2844B, UC2845B
http://onsemi.com
13
MUR110
+
-
+
-
S
R
+
R
R
5.0V Ref
Q
Bias
EA
5(9)
7(11)
6(10)
5(8)
3(5)
0.5
MTP
4N50
1(1)
2(3)
4(7)
8(14)
33k
1.0nF
470pF
150k
100
pF
18k
4.7k
Figure 30. 7 W Off−Line Flyback Regulator
0.01
100
+
1.0k
115 Vac
4.7W
MDA
202
250
56k
4.7k
3300
pF
1N4935 1N4935
+
+
68
47
1N4937
1N4937
680pF
2.7k
L3
L2
L1
++
++
++
1000
1000
2200
10
10
1000
5.0V/4.0A
5.0V RTN
12V/0.3A
±12V RTN
-12V/0.3A
Primary: 45 Turns #26 AWG
Secondary ±12 V: 9 Turns #30 AWG (2 Strands) Bifiliar Wound
Secondary 5.0 V: 4 Turns (six strands) #26 Hexfiliar Wound
Secondary Feedback: 10 Turns #30 AWG (2 strands) Bifiliar Wound
Core: Ferroxcube EC35-3C8
Bobbin: Ferroxcube EC35PCB1
Gap: ≈ 0.10" for a primary inductance of 1.0 mH
MUR110
MBR1635
T1
22
Osc
T1 -
7(12)
Comp/Latch
T
L1
L2, L3
- 15 mH at 5.0 A, Coilcraft Z7156
- 25 mH at 5.0 A, Coilcraft Z7157
1N5819
Test Conditions Results
Line Regulation: 5.0 V
±12 V
V
in
= 95 Vac to 130 Vac
D = 50 mV or ±0.5%
D = 24 mV or ±0.1%
Load Regulation: 5.0 V
±12 V
V
in
= 115 Vac, I
out
= 1.0 A to 4.0 A
V
in
= 115 Vac, I
out
= 100 mA to 300 mA
D = 300 mV or ±3.0%
D = 60 mV or ±0.25%
Output Ripple: 5.0 V
±12 V
V
in
= 115 Vac 40 mV
pp
80 mV
pp
Efficiency V
in
= 115 Vac 70%
All outputs are at nominal load currents unless otherwise noted.
