LNK520 Datasheet, PDF (2/20 Pages) Power Integrations, Inc. – Energy Efficient, CV or CV/CC Switcher for Very Low Cost Adapters and Chargers

LNK520
CONTROL
VC
0
ZC
SHUNT REGULATOR/
ERROR AMPLIFIER
5.6 V
5.6 V
4.7 V
1
SHUTDOWN/
AUTO-RESTART
+
-
INTERNAL
SUPPLY
÷8
DRAIN
CURRENT
LIMIT
ADJUST
CURRENT LIMIT
COMPARATOR
I_FB
OSCILLATOR
DMAX
CLOCK
SAW
IDCS
RE
HYSTERETIC
THERMAL
SHUTDOWN
-
+
PWM
COMPARATOR
LOW
FREQUENCY
OPERATION
SQ
R
Figure 2. Block Diagram.
LEADING
EDEGDGEE
BLANKING
SOURCE
PI-2777-032503
Pin Functional Description
DRAIN (D) Pin:
Power MOSFET drain connection. Provides internal operating
current for start-up. Internal current limit sense point for drain
current.
CONTROL (C) Pin:
Error amplifier and feedback current input pin for duty cycle
and current limit control. Internal shunt regulator connection
to provide internal bias current during normal operation. It is
also used as the connection point for the supply bypass and
auto-restart/compensation capacitor.
SOURCE (S) Pin:
Output MOSFET source connection for high voltage power
return. Primary side control circuit common and reference
point.
LNK520
S1
S2
8C
7S
S3
S4
5D
P Package (DIP-8B)
G Package (SMD-8B)
Figure 3. Pin Configuration.
PI-3790-121503
2
E
2/05