AIC3843 Datasheet, PDF (7/11 Pages) Analog Intergrations Corporation – Current-Mode PWM Controller

AIC3843
Open-Loop Laboratory Fixture
1k
8
V _REF
SHUTDOWN
1
COMP
330O
3
I _SENSE
SHUTDOWN
500
TO CURRENT SENSE
RESISTOR
Fig. 6-1
Fig. 6-2
Shutdown of the AIC3843 can be accomplished by two methods; either raise pin 3 above 1V or pull pin 1 below a voltage two-diode
drops above ground. Either method causes the output of the PWM comparator to be high (refer to block diagram). The PWM latch
is reset dominant so that the output will remain low until the next clock cycle after the shutdown condition at pin 1 and/or 3 is
removed. In one example, an externally latched shutdown may be accomplished by adding an SCR, which will be reset by cycling
Vcc below the lower UVLO threshold. At this point the reference turns off, allowing the SCR to reset.
Offline Flyback Regulator
R1
5Ω
1W
VARO
C1
VM68
250µF
117 VAC
250V
R2
56K
2W
R4
R3
4.7k 20k
7
2
R5 150k ₁
C5
0.01 µF
AIC3843
C14 100pF
86
R6
10k
3
45
C6
0.0022µF
L1
D6
10µH
1N3612
D2
C2 _{100µF C3}
25V 22µF
R12
C9
T1
USD945
+5V
2W
4.7K
3300pF
N5
C10
C11
4700µF 4700µF
D4
1N3613
Np
600V
10V
10V
COM
D7 UFS1002
1N3613
D4
R9
68Ω
3W
C4
Nc
25V
47µF
N12
N12
16V
C12
2200µF
C13
D8
2200 µF
16V
+12V
±12V COM
-12V
UES1002
USD1120
R7
22Ω _R8
1k
C7
470pF
Q1
UFN833
R10
R13
0.55Ω
10K
1W
16V
C8
680pF
D5
R11
2.7k
1N3613
2W
Power Supply Specifications
1. Input Voltage
95VAC to 130VA
(50Hz/60Hz)
2. Line Isolation
3750V
3. Switching Frequency 40kHz
4. Efficiency @ Full Load 70%
5. Output Voltage:
A. +5V, ±5%; 1A to 4A load
Ripple voltage: 50mV P-P Max
B. +12V, ±3%; 0.1A to 0.3A load
Ripple voltage: 100mV P-P Max
C. -12V, ±3%; 0.1A to 0.3A load
Ripple voltage: 100mV P-P Max
Fig. 7
7