UC3844, 45 UC2844, 45
Figure 29. 27 Watt Off–Line Flyback Regulator
L1
MBR1635
2200
+
4.7Ω
3300pF
MDA
202
4.7k
250
5.0V/4.0A
T1
+
+
+
+
1000
56k
115Vac
5.0V RTN
12V/0.3A
MUR110
1000
1N4935
68
1N4935
L2
10
7(12)
+
+
±
12V RTN
47
100
1000
10
L3
8(14)
+
–
+
+
5.0V
ref
–12V/0.3A
+
0.01
MUR110
680pF
1N4937
Bias
+
–
+
33k
7(11)
1N4937
2.7k
4(7)
2(3)
22
Ω
Osc
T
S
6(10)
+
MTP
4N50
1.0nF
1N5819
18k
+
–
Q
–
+
5(8)
3(5)
R
EA
Comp/Latch
4.7k
1.0k
470pF
1(1)
0.5Ω
5(9)
T1 – Primary: 45 Turns # 26 AWG
T1 – Secondary 12 V: 9 Turns # 30 AWG
±
T1 – (2 strands) Bifiliar Wound
T1 – Secondary 5.0 V: 4 Turns (six strands)
T1 – #26 Hexfiliar Wound
T1 – Secondary Feedback: 10 Turns #30 AWG
T1 – (2 strands) Bifiliar Wound
Test
Conditions
= 95 Vac to 130 Vac
Results
Line Regulation: 5.0 V
V
in
∆ = 50 mV or ± 0.5%
∆ = 24 mV or ± 0.1%
± 12 V
T1 – Core: Ferroxcube EC35–3C8
T1 – Bobbin: Ferroxcube EC35PCB1
Load Regulation: 5.0 V
V
V
= 115 Vac, I
= 115 Vac, I
= 1.0 A to 4.0 A
= 100 mA to 300 mA ∆ = 60 mV or ± 0.25%
∆ = 300 mV or ± 3.0%
in
in
out
out
T1 – Gap
≈
0.01” for a primary inductance of 1.0 mH
± 12 V
L1 – 15
µH at 5.0 A, Coilcraft Z7156.
Output Ripple:
5.0 V
V
in
= 115 Vac
40 mV
80 mV
pp
pp
L2, L3 – 25
µH at 1.0 A, Coilcraft Z7157.
± 12 V
Efficiency
V
in
= 115 Vac
70%
All outputs are at nominal load currents, unless otherwise noted.
12
MOTOROLA ANALOG IC DEVICE DATA
ONSEMI [ ONSEMI ]
