TOP221-227
V
C
0
1
CONTROL
DRAIN
INTERNAL
SUPPLY
Z
C
SHUTDOWN/
AUTO-RESTART
SHUNT REGULATOR/
ERROR AMPLIFIER
+
-
÷ 8
-
5.7 V
4.7 V
5.7 V
+
+
-
V
I
LIMIT
I
FB
THERMAL
SHUTDOWN
S
R
Q
POWER-UP
RESET
Q
CONTROLLED
TURN-ON
GATE
DRIVER
OSCILLATOR
D
MAX
CLOCK
SAW
S
Q
Q
-
LEADING
EDGE
+
R
BLANKING
PWM
COMPARATOR
MINIMUM
ON-TIME
DELAY
R
E
SOURCE
PI-1935-091696
Figure 2. Functional Block Diagram.
Pin Functional Description
Tab Internally
DRAIN Pin:
Connected to Source Pin
Output MOSFET drain connection. Provides internal bias
current during start-up operation via an internal switched high-
voltage current source. Internal current sense point.
DRAIN
SOURCE
CONTROL Pin:
CONTROL
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.
TO-220 (YO3A)
1
8
7
6
5
SOURCE
SOURCE
SOURCE
CONTROL
SOURCE (HV RTN)
SOURCE (HV RTN)
SOURCE (HV RTN)
DRAIN
2
3
4
SOURCE Pin:
Y package – Output MOSFET source connection for high
voltage power return. Primary side circuit
common and reference point.
P and G package – Primary side control circuit common and
reference point.
DIP-8 (P08A)
SMD-8 (G08A)
PI-2084-052198
SOURCE (HV RTN) Pin: (P and G package only)
Output MOSFET source connection for high voltage power return.
Figure 3. Pin Configuration.
C
2
12/97
POWERINT [ Power Integrations ]
