Datasheet

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OFFLINE FLYBACK REGULATOR
R1
5 Ω 1 W
117 VAC
VARO
VM 68
C1
250 µF
250 V
R2
56 kΩ
2 W
R12
4.7 kΩ
2 W
C9
3300 pF
600 V
N
P
D4
1N3613
D2
1N3612
D3
1N3612
NC
R3
20 kΩ
R4
4.7 kΩ
C4
47 µF
25 V
R9
68 Ω
3 W
C3
22 µF
C2
100 µF
25 V
7
2
1
8
4
5
3
6
UC3844
R5 150 kΩ
C14
100 pF
R6
10 kΩ
C5
0.01 µF
C6
0.0022 µF
USD1120
R7
22 Ω
R8
1 kΩ
C7
470 pF
R13
20 kΩ
R10
0.55 Ω
1 W
Q1
UFN833
T1 D6
U9D946
L1
N5
C10
4700 µF
10 V
C11
4700 µF
10 V
+6 V
COM
+12 V
±12 V COM
−12 V
D7
UF81002
N12
N12
C12
2200 µF
16 V
C13
2200 µF
16 V
D8
UES1002
C8
680 pF
600 V
D8
1N3613
R11
2.7 kΩ
2 W
Power Supply Specifications
SLOPE COMPENSATION
8
4
3
V
REF
R
T
/ C
T
I
SENSE
UC1842/3
0.1 mF
R
T
C
T
R1
R2
C
I
SENSE
R
SENSE
UC1842/3/4/5
UC2842/3/4/5
UC3842/3/4/5
SLUS223C – APRIL 1997 – REVISED JUNE 2007
1. Input Voltages
a. 5VAC to 130VA (50 Hz/60 Hz)
2. Line Isolation: 3750 V
3. Switchng Frequency: 40 kHz
4. Efficiency at Full Load 70%
5. Output Voltage:
a. +5 V, ± 5%; 1A to 4A load
Ripple voltage: 50 mV P-P Max
b. +12 V, ± 3%; 0.1A to 0.3A load
Ripple voltage: 100 mV P-P Max
c. –12 V, ± 3%; 0.1A to 0.3A load
Ripple voltage: 100 mV P-P Max
A fraction of the oscillator ramp can be resistively summed with the current sense signal to provide slope
compensation for converters requiring duty cycles over 50%.
8
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