AIC3843 Datasheet, PDF (1/11 Pages) Analog Intergrations Corporation – Current-Mode PWM Controller

AIC3843
Current-Mode PWM Controller
n FEATURES
l Low Start-Up Current (300µA Typical)
l Internal Precision Reference.
l 500KHz Current-Mode Operation.
l Pulse-by-Pulse Current Limiting.
l Automatic Feed-Forward Compensation.
l Optimized for Off-line and DC/DC Converters.
l Under-voltage Lockout with Hysteresis.
l Double Pulse Suppression.
l High Current Totem Pole Output.
n APPLICATIONS
l AC/DC Off-line Converter.
l DC/DC Off-line Converter.
n 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.
n TYPICAL APPLICATION CIRCUIT
2 _VFB
7
VCC
C2
+
R3 ^{300pF C3}
51K
1000P
FEEDBACK
SIGNAL
C5
0.1^µF
R4
7.5K
C4
2.2nF
1 _COMP
6
OUTPUT
R1
10
8 _VREF
GND ⁵
4 _RT/CT
3
ISENSE
AIC3843
C6
300P
C1
47µF
VCC
INDUCTOR
M1
R2
20K
R5
390
C7
RS
1nF
0.33
Current Mode PWM Control Circuit
Analog Integrations Corporation
4F, 9 Industry E. 9th Rd, Science-Based Industrial Park, Hsinchu, Taiwan
TEL: [phone]
FAX: [phone] www.analog.com.tw
DS-3843-00 012102
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