Table of Contents
Advertisement
1.2.4.3
Overvoltage protection circuit
This circuit operates the latch circuit when the voltage of pin
cally, this functions as the overvoltage protection for pin
pin
is supplied from the transformer's secondary coil. This voltage is proportional to the
output voltage, and also functions for the secondary output overvoltage when the control circuit
is open, etc.
Vin
4
+
Vin (on) = 17.5V
-
Vin (off) = 10V
OSC
Tcoff = 50µS
Functions of each terminal
Terminal No.
Symbol
1
D
2
S
3
GND
4
V
5
O.C.P. / F.B
UVLO
REC
Internal Bias
PWM Latch
S
_
R
Q
INH Latch
Q R
S
Name
Drain terminal
Source terminal
Ground terminal
Power terminal
IN
Overcurrent/feedback terminal
exceeds 25.5V (typ.). Basi-
in the control circuit. Normally, the
OVP
+
-
Latch
Delay
TSD
+
-
INH Comp.
+
-
Vth=1.45V
OCP Comp.
+
-
Icont
Vth=0.73V
Control circuit power input
Overcurrent detection signal and
constant-voltage control signal input
1 - 7
Vth = 25.5V
Ta = 155°C
REG
1
Drive
2
5
3
Function
MOSFET drain
MOSFET source
Ground
D
S
OCP/FB
GND
Advertisement
Chapters
Table of Contents
