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STR-W6756
Universal-Input/140 W Off-Line Quasi-
Resonant Flyback Switching Regulator
The STR-W6756 is a quasi-resonant regulator specifically designed
to satisfy the requirements for increased integration and reliability in
switch-mode power supplies. It incorporates a primary control and drive
circuit with an avalanche-rated power MOSFET. The regulator exhibits
only low-level high-frequency EMI noise because of soft switching of
the MOSFET close to ground (bottom point). A bottom-skip function
minimizes an increase of operational frequency during light loads to
improve system efficiency over the entire load range.
Covering the power range from below 240 watts for a 230 VAC
input, or 140 watts for a universal input (85 to 264 VAC), this device
can be used in a range of applications, from DVD and VCR players to
ac adapters for cellular phones and digital cameras. An auto-standby
function, which is internally triggered by sensing on time, reduces
power consumption at light load. An externally triggered standby mode
reduces the input power further. Multiple protections, including the
avalanche-energy-guaranteed MOSFET, provide high reliability of
system design.
Cycle-by-cycle current limiting, undervoltage lockout with hyster-
esis, and overvoltage protection protect the power supply during the
normal overload and fault conditions. Overvoltage protection is latched
after a short delay. The latch may be reset by cycling the input supply.
Low start-up current and a low-power standby mode selected from the
secondary circuit completes a comprehensive suite of features. The
STR-W6756 is provided in a fully molded TO-220-style flange-
mounted, high power, isolated plastic package.
FEATURES
AND
BENEFITS
■
Rugged 650 V Avalanche-Rated MOSFET
Simplified Surge Absorption
No V
DSS
Derating Required
■
0.73
Ω
Maximum
r
DS(on)
■
Two Operational Modes by Automatic Switching:
Quasi-Resonant Mode for Normal Operation
Burst Mode for Standby Operation or Light Loads
■
Automatic or Manually Triggered Burst Standby
Input Power <0.1 W at No Load
■
Low Operating Current (6 mA typ)
— continued
Always order by complete part number, e.g.,
STR-W6756
.
Data Sheet
28103.33*
ABSOLUTE MAXIMUM RATINGS
at T
A
= +25°C
Control Supply Voltage, V
CC
. . . .
35 V
Drain-Source Voltage, V
DSS . . . . . .
650 V
Drain Switching Current, I
D
. . . . .
15 A*
Peak Drain Switching Current,
I
DM
. . . . . . . . . . . . . . . . . . . . . .
15 A
Single-Pulse Avalanche Energy,
E
AS
. . . . . . . . . . . . . . . . . . .
400 mJ
OCP/BD Voltage Range,
V
OCP
. . . . . . . . . . . .
–1.5 V to +5 V
FB Input Current, I
FB
. . . . . . . .
10 mA
FB Voltage Range, V
FP
–0.5 V to +9 V
Package Power Dissipation, P
D
control (V
CC
× I
CC(ON)
) . . . . . .
0.8 W
MOSFET (V
DSS
× I
D
) . . .
See Graph
MOSFET Channel Temp., T
J
.
+150°C
Internal Frame Temp., T
F
. . . .
+115°C
Operating Temperature Range,
T
A
. . . . . . . . . . .
-20°C to +115°C†
Storage Temperature Range,
T
S
. . . . . . . . . . . .
-40°C to +125°C
* Drain switching current is limited by tem-
perature (page 2) and safe operating area
(page 5).
†For the availability of parts meeting -40°C
requirements, contact Allegro’s Sales Represen-
tative.
Sanken Power Devices
from Allegro MicroSystems
ALLEGRO [ ALLEGRO MICROSYSTEMS ]
