top412 Power Integrations, Inc., top412 Datasheet - Page 2

• Manufacturer Part Number: top412
• Description: Three-terminal Dc To Dc Pwm Switch
• Manufacturer: Power Integrations, Inc.

Figure 2. Functional Block Diagram.
Pin Functional Description
DRAIN 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.
CONTROL Pin:
Error amplifier and feedback current input pin for duty cycle
control. Internal shunt regulator connection to provide internal
bias current during normal operation. Trigger input for latching
shutdown. It is also used as the supply bypass and auto-restart/
compensation capacitor connection point.
SOURCE Pin:
Output MOSFET source connection. Primary-side circuit
common, power return, and reference point.
2
TOP412/414
CONTROL
A
4/99
R E
Z C
SHUNT REGULATOR/
I FB
ERROR AMPLIFIER
OSCILLATOR
V C
CLOCK
D MAX
SAW
+
-
5.7 V
EXTERNALLY
TRIGGERED
SHUTDOWN
SHUTDOWN
COMPARATOR
5.7 V
4.7 V
THERMAL
PWM
+
-
AUTO-RESTART
SHUTDOWN/
+
-
POWER-UP
RESET
0
1
INTERNAL
SUPPLY
R
S
÷ 8
Figure 3. Pin Configuration.
Q
Q
S
R
CONTROL
Q
Q
SOURCE
SOURCE
SOURCE
G Package (SMD-8)
2
1
3
4
BLANKING
LEADING
EDGE
CONTROLLED
TURN-ON
DRIVER
GATE
8
6
5
7
+
-
MINIMUM
ON-TIME
SOURCE (HV RTN)
SOURCE (HV RTN)
SOURCE (HV RTN)
DRAIN
DELAY
V I
LIMIT
PI-1746-011796
PI-2208-120798
DRAIN
SOURCE