SR036/SR037
SR036
SR037
Inductorless, Dual Output Off-Line Regulators
Features
❑
Accepts peak input voltages up to 700V
❑
Operates directly off of rectified 120V AC or 230V AC
❑
Integrated linear regulator
❑
Minimal power dissipation
General Description
The Supertex SR036 and SR037 are inductorless, dual output
off-line controllers, providing up to
1.0W
of output power. They
do not require any transformers, inductors, or high voltage
input capacitors. The input voltage, HV
IN
, is designed to
operate from an unfiltered full wave rectified 120V or 230V AC
line. It is designed to control an external N-channel MOSFET
or IGBT. When HV
IN
is less than 45V, the external transistor is
turned-on allowing it to charge an external capacitor connected
to V
SOURCE
. An unregulated DC voltage will develop on V
SOURCE
.
Once HV
IN
is above 45V, the transistor is turned off. The
maximum gate voltage for the external transistor is 24V. The
unregulated voltage is approximately 18V. The SR036 also
provides a regulated 3.3V whereas the SR037 provides a
regulated 5.0V.
WARNING!!! Galvanic isolation is not provided. Dangerous
voltages are present when connected to the AC line. It is
the responsibility of the designer to assure adequate
safeguards are in place to protect the end user from
electrical shock.
❑
No high voltage capacitors required
❑
Up to
1.0W
output power
❑
No transformers or inductors required
Applications
❑
3.3V or 5.0V power supplies
❑
White goods
❑
Appliances
❑
SMPS house keeping power supplies
❑
Small off-line low voltage power supplies
❑
Lighting controls
SR03x Typical Application Circuit
d
e
d
n
e
m
m
co
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e
n
R
ig
t
s
o
e
N
D
w
e
N
r
o
F
~
18V Unregulated
GN2470
1.0µF
470µF
Surge
Protection
Gate
120VAC
or
230VAC
HV
IN
SR036
or
SR037
V
SOURCE
V
OUT
SR036:
V
OUT
=
3.3V
Regulated
SR037:
V
OUT
= 5.0V Regulated
1.0µF
B092005
B092005
1
SUPERTEX [ Supertex, Inc ]
