AN4003 Datasheet, PDF (2/28 Pages) Fairchild Semiconductor – PC POWER SUPPLY DESIGN WITH KA3511

ORDERING INFORMATION
Device
KA3511
Package
22 DIP
Operating Temperature
-25°C ~ 85°C
FEATURES
• Complete PWM control and house keeping circuitry
• Few external components
• Precision voltage reference trimmed to 2%
• Dual output for push-pull operation
• Each output TR for 200mA sink current
• Variable duty cycle by dead time control
• Soft start capability by using dead time control
• Double pulse suppression logic
• Over voltage protection for 3.3V / 5V / 12V
• Under voltage protection for 3.3V / 5V / 12V
• One more external input for various protection (PT)
• Remote on/off control function (PS-ON)
• Latch function controlled by remote and protection input
• Power good signal generator with hysteresis
• 22-Pin dual in-line package
2. BLOCK DIAGRAM
22-DIP-400
V5 V12
R_{T 7}
C_{T 8}
COMP
2
E/A(-)
3
E/A(+)
4
DEAD TIME
CONTROL
19
12
VREF
V_{CC 1}
OSCILLATOR
PWM
CONTROL
DQ
CK Q
1.25V
DEAD TIME
CONTROLLER
0.1V
R
Q
S
INTERNAL
BIAS
VREF
Start Up
COMP1
5V
5V
VREF
Ichag
PG
GENERATOR
DELAY
CONTROLLER _{REMOTE ON/OFF}
1.4V
VREF _OVP
COMP
1.25V
DET
9
COMP2
1.25V
COMP3
1.8V 0.6V ^1.8V
0.6V
UVP
COMP
1.25V
10
T_PG
2.2uF
17
T_UVP
2.2uF
18
GND
22 C1
20 C2
21 E
5
T_REM
6
REM
(PS-ON)
11 PG
16 PT
15 V12
14 V5
13 V3.3
Rev C, November 1999
2