LNK623-626
DRAIN
(D)
BYPASS
(BP)
+
+
REGULATOR
6V
FB
OUT
6V
5V
FEEDBACK
(FB)
V
TH
D
Q
-
STATE
MACHINE
I
LIM
DC
MAX
Reset
V
ILIMIT
Drive
-
t
SAMPLE-OUT
6.5 V
FB
FAULT
Auto-Restart
Open-Loop
THERMAL
SHUTDOWN
t
SAMPLE-OUT
OSCILLATOR
+
DC
MAX
SAMPLE
DELAY
SOURCE
(S)
V
ILIMIT
LEADING
EDGE
BLANKING
SOURCE
(S)
I
LIM
-
Current Limit
Comparator
PI-5197-110408
Figure 2
Functional Block Diagram.
Pin Functional Description
DRAIN (D) Pin:
This pin is the power MOSFET drain connection. It provides
internal operating current for both start-up and steady-state
operation.
BYPASS (BP) Pin:
This pin is the connection point for an external bypass capacitor
for the internally generated 6 V supply.
FEEDBACK (FB) Pin:
During normal operation, switching of the power MOSFET is
controlled by this pin. This pin senses the AC voltage on the
bias winding. This control input regulates the output voltage
based on the flyback voltage of the bias winding.
SOURCE (S) Pin:
This pin is internally connected to the output MOSFET source
for high voltage power and control circuit common returns.
P Package (DIP-8C)
FB
BP
D Package (SO-8C)
1
2
8
7
6
S
S
S
S
FB
BP
D
1
2
8
7
6
S
S
S
S
D
4
5
4
3a
5
3b
PI-5198-071608
Figure 3.
Pin Configuration.
2
Rev. E 09/09
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