Operates directly off of rectified 120V AC or 240V AC
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Integrated linear regulator
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Minimal power dissipation
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No high voltage capacitors required
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No transformers or inductors required
General Description
The Supertex SR036 and SR037 are inductorless, dual output
off-line controllers. 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 240V AC line. It is designed to control an
external N-channel MOSFET. When HV
IN
is between V
GS(th)
to
40V, where V
GS(th)
is the threshold voltage of the external
MOSFET, the external N-channel MOSFET 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 N-channel MOSFET is turned off. The maximum
gate voltage for the external MOSFET 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.
Applications
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3.3V or 5.0V power supplies
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SMPS house keeping power supplies
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White goods
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Appliances
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Small off-line low voltage power supplies
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Lighting controls
SR03x Typical Application Circuit
~
18V Unregulated
100碌F
Gate
Surge
Protection
120VAC
or
240VAC
SR036
or SR037
V
SOURCE
V
OUT
SR036: V
OUT
=3.3V Regulated
SR037: V
OUT
=5.0V Regulated
1.0碌F
06/13/02
Supertex Inc. does not recommend the use of its products in life support applications and will not knowingly sell its products for use in such applications unless it receives an adequate "products liability
indemnification insurance agreement." Supertex does not assume responsibility for use of devices described and limits its liability to the replacement of devices determined to be defective due to
workmanship. No responsibility is assumed for possible omissions or inaccuracies. Circuitry and specifications are subject to change without notice. For the latest product specifications, refer to the
Supertex website: http://www.supertex.com. For complete liability information on all Supertex products, refer to the most current databook or to the Legal/Disclaimer page on the Supertex website.
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