DPA422-426
V
C
0
1
DRAIN (D)
CONTROL (C)
Z
C
INTERNAL
SUPPLY
SHUNT REGULATOR/
ERROR AMPLIFIER
+
-
SOFT START
5.8 V
4.8 V
-
5.8 V
+
INTERNAL UV
COMPARATOR
I
FB
V
I (LIMIT)
CURRENT
LIMIT
ADJUST
SOFT
START
-
÷ 8
ON/OFF
+
V
+ V
T
BG
SHUTDOWN/
CURRENT LIMIT
COMPARATOR
AUTO-RESTART
EXTERNAL
CURRENT LIMIT (X)
HYSTERETIC
THERMAL
STOP LOGIC
SHUTDOWN
1 V
LINE-SENSE (L)
CONTROLLED
TURN-ON
V
BG
GATE DRIVER
STOP SOFT-
OV/UV
START
D
LINE
SENSE
MAX
DC
DC
MAX
MAX
CLOCK
SAW
S
R
Q
-
LEADING
EDGE
BLANKING
300/400 kHz
OSCILLATOR
FREQUENCY (F)
+
PWM
COMPARATOR
CYCLE
SKIPPING
R
E
SOURCE (S)
PI-2760-070501
Figure 2. Functional Block Diagram.
Pin Functional Description
SOURCE (S) Pin:
DRAIN (D) Pin:
Output MOSFET source connection for the power return.
Primary side control circuit common and reference point.
High-voltage power MOSFET drain output. The internal startup
bias current is drawn from this pin through a switched high-
voltage current source. Internal current limit sense point for
drain current.
Tab internally connected
to SOURCE pin
CONTROL (C) Pin:
Error amplifier and feedback current input pin for duty cycle
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.
(See layout considerations)
R Package
(TO-263-7C)
P Package (DIP-8)
G Package (SMD-8)
LINE-SENSE (L) Pin:
Input pin for overvoltage (OV), undervoltage (UV) lock out, line
feed-forward with the maximum duty cycle (DCMAX) reduction,
remote ON/OFF and synchronization. A connection to
SOURCE pin disables all functions on this pin.
C
L
S
S
D
S
1
2
8
7
X
F
3
4
6
5
EXTERNAL CURRENT LIMIT (X) Pin:
Input pin for external current limit adjustment and remote
ON/OFF. A connection to SOURCE pin disables all functions
on this pin.
1 2 3 4 5
C L X S F
7
D
PI-4030-110507
FREQUENCY (F) Pin:
Input pin for selecting switching frequency: 400 kHz if
connected to SOURCE pin and 300 kHz if connected to
CONTROL pin.
Figure 2. Pin Configuration (Top View).
3
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Rev. T 12/12
POWERINT [ Power Integrations ]
