L6565
QUASI-RESONANT SMPS CONTROLLER
QUASI-RESONANT (QR) ZERO-VOLTAGE-
SWITCHING (ZVS) TOPOLOGY
s
LINE FEED FORWARD TO DELIVER
CONSTANT POWER vs. MAINS CHANGE
s
FREQUENCY FOLDBACK FOR OPTIMUM
STANDBY EFFICIENCY
s
PULSE-BY-PULSE & HICCUP-MODE OCP
s
ULTRA-LOW START-UP (< 70µA) AND
QUIESCENT CURRENT (< 3.5mA)
s
DISABLE FUNCTION (ON/OFF CONTROL)
s
1% PRECISION (@ T
j
= 25°C) INTERNAL
REFERENCE VOLTAGE
s
±400mA TOTEM POLE GATE DRIVER WITH
UVLO PULL-DOWN
s
BLUE ANGEL, ENERGY STAR, ENERGY
2000 COMPLIANT
APPLICATIONS
s
TV/MONITOR SMPS
s
AC-DC ADAPTERS/CHARGERS
s
DIGITAL CONSUMER
s
PRINTERS, FAX MACHINES,
PHOTOCOPIERS AND SCANNERS
s
DIP8(Minidip)
SO-8
ORDERING NUMBERS:
L6565N
L6565D
DESCRIPTION
The L6565 is a current-mode primary controller IC,
specifically designed to build offline Quasi-resonant
ZVS (Zero Voltage Switching at switch turn-on) fly-
back converters.
Quasi-resonant operation is achieved by means of a
transformer demagnetization sensing input that trig-
gers MOSFET's turn-on.
BLOCK DIAGRAM
COMP
2
1
INV
-
+
2.5V
VOLTAGE
REGULATOR
2V
-
+
-
+
5pF
LINE VOLTAGE
FEEDFORWARD
40K
4
CS
VFF
3
8
V
CC
20V
R1
+
R2
V
REF2
-
Blanking
START
UVLO
S
Q
INTERNAL
SUPPLY
Hiccup-mode
OCP
R
Q
V
CC
7
GD
DRIVER
Starter
STOP
ZERO CURRENT
DETECTOR
+
2.1V
1.6V
BLANKING
STARTER
-
Hiccup-mode
OCP
DISABLE
6
GND
5
ZCD
January 2003
1/17
STMICROELECTRONICS [ STMICROELECTRONICS ]
