LNK500
DRAIN
0
1
CONTROL
V
C
INTERNAL
SUPPLY
Z
C
SHUTDOWN/
AUTO-RESTART
CURRENT
LIMIT
ADJUST
SHUNT REGULATOR/
ERROR AMPLIFIER
+
-
÷ 8
-
5.6V
4.7
V
CURRENT LIMIT
COMPARATOR
5.6
V
+
-
+
I
HYSTERETIC
THERMAL
FB
SHUTDOWN
OSCILLATOR
D
MAX
CLOCK
SAW
S
R
Q
-
+
PW
M
COMPARATOR
I
DCS
LEADING
EDGE
BLANKING
EDGE
LOW
FREQUENCY
OPERATION
R
E
SOURCE
PI-3416-032603
Figure 2. Block Diagram.
Pin Functional Description
LNK500
DRAIN (D) Pin:
S
S
C
S
1
2
8
7
Power MOSFET drain connection. Provides internal operating
current for start-up. Internal current limit sense point for drain
current.
S
S
3
4
CONTROL (C) Pin:
5
D
Error amplifier and feedback current input pin for duty cycle
andcurrentlimitcontrol. Internalshuntregulatorconnectionto
provide internal bias current during normal operation. It is also
used as the connection point for the supply bypass and auto-
restart/compensation capacitor.
P Package (DIP-8B)
G Package (SMD-8B)
PI-3417-111802
Figure 3. Pin Configuration.
SOURCE (S) Pin:
Output MOSFET source connection for high voltage power
return. Primary side control circuit common and reference
point.
B
3/03
2
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