AIC3843
Current-Mode PWM Controller
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FEATURES
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Low Start-Up Current (300µA Typical)
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Internal Precision Reference.
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500KHz Current-Mode Operation.
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Pulse-by-Pulse Current Limiting.
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Automatic Feed-Forward Compensation.
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Optimized for Off-line and DC/DC Converters.
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Under-voltage Lockout with Hysteresis.
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Double Pulse Suppression.
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High Current Totem Pole Output.
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DESCRIPTION
The AIC3843 control IC provides the features
that are necessary to implement off-line or
DC/DC Converter fixed-frequency current-mode
schemes with a minimum number of external
components. This integrated circuits features
an under-voltage lockout (UVLO) with approxi-
mately 300µA start-up current, a precision
reference trimmed for accuracy at the error
amplifier input, high gain error amplifier, current
sensing comparator, logic to insure latched
operation, and a totem-pole output stage
designed to source or sink high peak current.
The output stage, suitable for driving the N-
channel MOSFETs, is low in the off state.
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APPLICATIONS
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AC/DC Off-line Converter.
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DC/DC Off-line Converter.
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TYPICAL APPLICATION CIRCUIT
2
C2
R3
51K
FEEDBACK
SIGNAL
300pF
C3
1000P
6
OUTPUT
GND
5
VFB
7
VCC
+
R1
10
R2
20K
R5
C6
300P
390
C7
1nF
RS
0.33
C1
47
µ
F
VCC
INDUCTOR
M1
1
8
COMP
VREF
R4
7.5K
C5
0.1
µ
F
4
RT/CT
ISENSE
3
AIC3843
C4
2.2nF
Current Mode PWM Control Circuit
Analog Integrations Corporation
4F, 9 Industry E. 9th Rd, Science-Based Industrial Park, Hsinchu, Taiwan
TEL: 886-3-5772500
FAX: 886-3-5772510
www.analog.com.tw
DS-3843-00 012102
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AIC [ ANALOG INTERGRATIONS CORPORATION ]
