|
|
PDF SR086 Data sheet ( Hoja de datos )
| Número de pieza | SR086 | |
| Descripción | Adjustable Off-Line Inductorless Switching Regulator | |
| Fabricantes | Supertex Inc | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de SR086 (archivo pdf) en la parte inferior de esta página. Total 7 Páginas | ||
|
No Preview Available !
Supertex inc.
SR086
Adjustable Off-Line
Inductorless Switching Regulator
Features
►►Efficient operation without magnetics
►►No high voltage capacitors
►►Adjustable main output voltage (9.0 to 50V)
►►Additional 3.3V internal regulator
►►Up to 100mA combined output current
►►Single BOM for 120VAC/230VAC
►►Built-in soft start
►►Less than 200mW standby power
Applications
►► White goods
►► Household appliances
►► Lighting controls
►► Circuit breakers
►► Keep-alive supplies
General Description
The Supertex SR086 is an inductorless switching regulator designed
to operate directly from a rectified AC line. The operating principle is
to turn on a pass transistor when the rectified AC is below the output
voltage, and to turn it off when the output voltage reaches a specific
level. A linear regulator supplied by VOUT provides an additional fixed
3.3V output. Efficiencies of around 55% may be realized for loads
up to 1.0W in 120VAC applications, with around 50% efficiencies for
loads up to 800mW in 230VAC applications.
A logic-level enable input allows the SR086 to be disabled – useful
when it is employed as a keep-alive power supply.
WARNING! Galvanic isolation is not provided. Dangerous
voltages are present when connected to the AC line. It is the
responsibility of the designer employing the SR086 to ensure
adequate safeguards are in place to protect the end user from
electrical shock.
The circuits shown in this datasheet are not guaranteed to meet
surge and conducted EMI requirements. The effectiveness of these
circuits may vary with a particular application. The designer should
conduct tests to ascertain compliance with applicable standards and
regulations.
Typical Application Circuit
90 to
270VAC
50/60Hz
1.25A
275V
50A
1.0kV
1.0A STGD5NB120SZ
390kΩ
1.1MΩ
100nF
1.0µF
470µF
Enable
GATE VGD VOUT
VIN FB
SR086
EN VREG
GND
3.3V
@60mA
100nF
VOUT
9.0 - 50VDC
@100mA - IREG
R1 = R2
VOUT - 1
1.25V
R122.4kΩ
Doc.# DSFP-SR086
D080613
Supertex inc.
www.supertex.com
1 page  
SR086
Output Voltage*
VOUT may be adjusted in the range of 9V to 50V*‚ by changing
feedback resistor R5 according to the following equation.
R5 = R6 [(VOUT / 1.25V) - 1]
Leave R6 at 12.4kΩ or less - it assures a minimum 100µA
load required for the proper operation of the SR086. Change
R3 and R4 according to the R3+R4 equation below. Select
C2 and C3 with appropriate voltage ratings. For C3, use a
low ESR capacitor with an adequate ripple current rating
(800mARMS). Use ceramic for C2.
Since VREG is a linear regulator supplied from VOUT, the maxi-
mum current available from VREG is reduced as VOUT is in-
creased due to power considerations.
IREG(max) = 1.5W / (VOUT - 3.3V), or 60mA, whichever is less.
Input Voltage
To reduce standby power for 230VAC-only applications,
or for supply voltages less than 90Vrms, R3 and R4 should
be changed according to the R3+R4 equation below. R1+R2
should remain at 400kΩ or less. Two resistors in series
are employed to ensure adequate creepage distances for
230VAC operation. For 120VAC-only applications, single re-
sistors may be employed.
the high inductance of the transformer (frequently in the
mH’s) interferes with the normal operation of the SR086 and
should not be used. This is not a concern with the normal
inductance of the AC line or for AC line filters.
AC Line
SR086
Circuitry
The SR086 draws current from the AC line in short, high
current pulses. The transformer’s high inductance tends to
limit the current pulse. Furthermore, inductive kickback on
the falling edge of the current pulse can create high voltage
spikes which must be absorbed by the transient protector.
EMI Capacitor
The use of a small-value capacitor from circuit common to
earth ground prevents the SR086 from operating and should
not be employed.
AC Line
SR086 &
Circuitry
earth
ground
circuit
common
Output Ripple*
Storage capacitor C3 was sized to provide about 2VP-P ripple
at 100mA load (IOUT + IREG). For lighter loads, C3 may be re-
duced. Conversely, C3 may be increased for lower ripple.
Use a low ESR capacitor with an adequate ripple current
rating (800mARMS for 100mA loads). Efficiency and output
current capability may drop with increased capacitance be-
cause of a smaller conduction angle associated with lower
ripple. Due to feedback hysteresis, ripple cannot be reduced
below 4%.
VRIPPLE(P-P) ≈ (IOUT + IREG ) / 2fINC3
m*VuRsEGt
requires at least 4V
not fall below 7.3V.
of
headroom.
Therefore,
VOUT,
including
ripple,
EMI
The SR086 circuit as depicted on Page 1, (Typical Application
Circuit), meets FCC Class B and CISPR 14-1 (household
appliances) requirements for conducted emissions, for
combined loads of less than 20mA (IOUT + IREG).
Fuse
Although the average current drawn from the AC line is
low, the RMS current is fairly high due to the current being
drawn in short, high-current pulses. Since a fuse is basically
a
resistor
with
a
power
dissipation
given
by
I2
RMS
R,
the
fuse
must be sized for the RMS current, not the average current.
For a 1.0W load and 120VAC the RMS current is 700mARMS,
and for a 0.5W load at 230VAC it is 360mARMS.
Line Transformer
During initial testing it is tempting to use an isolation
transformer or a variable transformer on theAC line. However,
R3 + R4 Equation:
(R3
+
R4)
<
√
2VIN2
-
VX2
π•
- VXcos-1
25µ
VX
√2 • VIN
where VX = VOUT + 15V
Use
Take
the minimum anticipated RMS
resistor tolerance into account,
value for
selecting
VthINe.
next lower standard value. Choosing a lower value
has no effect other than higher standby power.
Doc.# DSFP-SR086
D080613
Supertex inc.
5 www.supertex.com
5 Page | ||
| Páginas | Total 7 Páginas | |
| PDF Descargar | [ Datasheet SR086.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| SR086 | Adjustable Off-Line Inductorless Switching Regulator | Supertex Inc |
| SR087 | Adjustable Off-Line Inductorless Switching Regulator | Supertex Inc |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |