SUPERTEX SR037SG

SR036/SR037
SR036
SR037
Inductorless, Dual Output Off-Line Regulators
Features
General Description
❑ Accepts peak input voltages up to 700V
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 VSOURCE. An unregulated DC voltage will develop on VSOURCE.
Once HVIN 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.
❑ Operates directly off of rectified 120V AC or 230V AC
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❑ Integrated linear regulator
❑ Minimal power dissipation
❑ No high voltage capacitors required
❑ No transformers or inductors required
❑ Up to 1.0W output power
Applications
❑ 3.3V or 5.0V power supplies
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.
❑ SMPS house keeping power supplies
❑ White goods
❑ Appliances
❑ Small off-line low voltage power supplies
❑ Lighting controls
SR03x Typical Application Circuit
~18V Unregulated
1.0µF
120VAC
or
230VAC
470µF
Gate
Surge
Protection
GN2470
SR036
or SR037
HVIN
VSOURCE
SR036: VOUT = 3.3V Regulated
SR037: VOUT = 5.0V Regulated
VOUT
1.0µF
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B092005
1
SR036/SR037
Ordering Information
Package Options
VOUT
MSOP-8
SO-8 w/ Heat Slug
3.3V
SR036MG*
SR036SG
5.0V
SR037MG*
SR037SG
* Product supplied on 2500 piece carrier tape reel.
Pin Configuration
Absolute Maximum Ratings*
VIN, High Voltage Input
+700V
VOUT, Low Voltage Output
+6.0V
Storage Temperature
HVIN
1
8
Gate
N/C
2
7
Source
N/C
3
6
VOUT
GND
4
5
N/C
-65°C to +150°C
Soldering Temperature
+300°C
Power Dissipation, MSOP-8
300mW
Power Dissipation, SO-8 slug
1.50W1
MSOP-8
(top view)
HVIN
1
8
Gate
N/C
2
7
Source
N/C
3
6
VOUT
GND
4
5
N/C
* All voltages are referenced to GND.
1. When underside plate soldered to 2cm2 of exposed copper.
SO-8 Slug
Make no electrical connections
to Backside Plate
(top view)
*Absolute Maximum Ratings are those values beyond which damage to the
device may occur. Functional operation under these conditions is not implied.
Continuous operation of the device at the absolute rating level may affect device
reliability. All voltages are referenced to device ground.
Electrical Characteristics
(Over operating supply voltages unless otherwise specified, TA=0°C to +125°C)
Symbol
Parameter
Min
Typ
Max
700
Units
HVIN
Input voltage
VTH
HVIN voltage when Gate is pulled to ground
40
45
50
V
VGS
Gate to source clamp voltage
±10
±15
±20
V
VGATE
Gate to ground clamp voltage
V
VOUT
Regulated output voltage for the SO-8
with heat slug
∆VOUT
VOUT load regulation
Freq
Input AC frequency
407
V
18
20
24
SR036
2.97
3.30
3.63
SR037
4. 5
5.00
5.50
20
1 20
mV
100
Hz
40
V
Conditions
Peak transient voltage
Peak rectified AC voltage
IGS = ±100µA
VSOURCE = 10V
VSOURCE = 10V
VSOURCE = 10V,
ILoad = 0 to 50mA (1)
(1) Load current on the regulated output must not cause SR03 power dissipation to exceed max ratings. Worst case power dissipation is
given by:
P≈
VIN
2
185kΩ
+ (16V − VOUT ) × I OUT
Where IOUT is the load on the regulated output
2
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SR036/SR037
Typical Performance Curves
Gate Clamp
HVIN (off)
60
25
50
20
HVIN (V)
Vgate (V)
40
15
10
30
20
5
10
0
0
-40
-10
20
50
80
110
140
-40
-10
20
Temperature (°C)
50
80
110
140
Temperature (°C)
Gate Voltage
Regulator Output (SR037)
20
6
18
5
16
14
VGate (V)
VOUT (V)
4
3
12
10
8
2
6
4
1
2
0
0
0
5
10
15
25
20
0
10
20
Source Voltage (V)
30
40
50
60
70
80
HVIN (V)
Load Regulation (SR037)
HV Input Current
5.05
2100
125°C
5.00
1800
25°C
4.95
-40°C
VOUT (V)
1500
IIN (µA)
1200
900
Source=15V
25°C
4.85
4.80
600
Source=8V
25°C
4.75
300
4.70
4.65
0
0
50
100
150
200
250
300
350
0
400
HVIN (V)
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4.90
10
20
30
IOUT (mA)
3
40
50
SR036/SR037
Applications Information
Functional Block Diagram
Operating Principle
HVIN
The SR03x operates by controlling the conduction angle of the
external MOSFET or IGBT as shown in Figure 1. When the
rectified AC voltage is below the VTH threshold, the pass transistor
is turned on. The pass transistor is turned off when the rectified
AC is above HVIN(off). Output voltage (Vunreg) decays during the
periods when the switch is off and when the rectified AC is below
the output voltage. The amount of decay is determined by the
load and the value of C1. Since the switch only conducts with low
voltages across it, power dissipation is minimized.
VREF
Gate
Source
CM
Reg
VOUT
GND
Switch ON
HVIN
V TH
VUNREG
VREG
not to scale
Figure 1: Typical Waveforms
Power Dissipation
Power dissipation in the SR03 is from 2 sources. The first is due to the bias current (or overhead) required to operate the device. This may
be calculated from PBIAS = VIN2 / 185ký where VIN is the input voltage in VRMS. The second source of power dissipation is the 3.3/5V linear
regulator and may be calculated from PREG = (16V - VOUT) * IREG, where VOUT is 3.3V or 5V, and IREG is the load current on the 3.3/5V output.
The total power dissipated by the SR03x is the sum of these two: PBIAS + PREG. (These equations are conservative – actual dissipation may
be less.)
To adequately dissipate the power, the underside plate of the SR03xSG should be soldered to at least 2cm2 of exposed copper area on
the PCB.
Power is also dissipated by the pass transistor. Power dissipated by the transistor will be (16V * ITOTAL) * (1/Eff -1) where ITOTAL is the sum
of the load currents on the regulated and unregulated outputs and Eff is the converter efficiency (see Efficiency Graph next page). The
transistor should be soldered to at least 5cm2 of exposed copper area on the PCB for heatsinking.
Transformers
4
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SR036/SR037
Using a MOSFET in place of an IGBT
~18V Unregulated
VN2460
Surge
Protection
120VAC
or
230VAC
270µF
Gate
1.0µF
SR036
or SR037
HVIN
VSOURCE
SR036: VOUT=3.3V Regulated
SR037: VOUT=5.0V Regulated
VOUT
1.0µF
SRO3 Efficiency
SR03 Efficiency
50
VN2460, no EMI
Efficiency (%)
GN2470, no EMI
40
30
VN2460, w/EMI
GN2470, w/EMI
20
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6
PUNREG (W)
Efficiency and EMI Test Circuit
120/230VAC
50/60Hz
GN2470
P6KE
400CA
EMI
Suppressor
VUNREG
1.0μF
CG
220pF
RG
180kΩ
VIN
GATE
SR03x
SOURCE
GND
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VREG
VREG
CREG
1.0μF
5
220μF (VN2460)
470μF (GN2470)
SR036/SR037
SR03 Circuit using VN2460
(with EMI Suppression Circuit)
6
B092005
SR036/SR037
SR03 Circuit using GN2470 (no EMI Suppressor)
120VAC/60Hz Limits per 47CFR15.107 for Class B devices. 50mA total load.
Hot
Average
Quasi-peak
Neutral
208VAC/60Hz (230VAC/50Hz not available). Limits per CISPR 14-1 for household appliances. 25mA total load.
Neutral
Average
Quasi-peak
Hot
B092005
7
SR036/SR037
SR03 Circuit using GN2470 (no EMI Suppressor)
120VAC/60Hz Limits per 47CFR15.107 for Class B devices. 100mA total load.
Hot
Average
Quasi-peak
Neutral
8
B092005
SR036/SR037
Applications Information, continued
GN2470
Fuse
VUNREG
1.0µF
220µF
Surge
Protection
120VAC
or
230VAC
1KΩ
Gate
HVIN
ON/OFF
Source
SR036
or SR037
VOUT
VREG
1.0µF
GND
TN2106K1
Figure 2: Example Circuit with Enable Control
Figure 2 is an example circuit using the SR036 or SR037 along
with a Supertex GN2470 IGBT to generate an unregulated
voltage of approximately 18V and a regulated voltage of 3.3V for
the SR036 or 5.0V for the SR037. The combined total output
Fuse
current is typically 50mA. The TN2106K1 in series with a 1Ký
resistor can be added for applications requiring an enable
control.
GN2470
2N3904
Vout1 = 5.0V
1.0µF
220µF
Surge
Protection
120VAC
or
230VAC
10KΩ
1.0µF
1.0MΩ
Gate
HVIN
Vz
5.6V
Source
V OUT
SR036
Vout 2 = 3.3V
1.0µF
GND
Figure 3: Generating Two Regulated Voltages
For applications requiring two regulated voltages, an inexpensive discrete linear regulator can be added to regulate the
unregulated output as show in Figure 3. The discrete linear
regulator consists of a Zener diode, a resistor and a bipolar
transistor. The regulated voltage, Vout1, is determined by the
B092005
Zener diode voltage minus the base-to-emitter voltage drop of
0.6V. Figure 3 uses a 5.6V Zener diode to obtain a 5.0V output.
Different Zener diode voltages can be used to obtain different
regulated output voltages.
9
SR036/SR037
Applications Information, continued
Unregulated Voltage
GN2470
Fuse
120VAC
or
230VAC
Surge
Protection
1.0µF
1N4001
220µF
Gate
HVIN
12V Coil
Relay
Source
Logic
Control
Circuit
3.3V
SR036
VOUT
VN2110K1
1.0µF
GND
Figure 4: Driving 12V Relay Coils
The circuit shown in Figure 4 uses the SR036 to supply a
regulated 3.3V for the logic control circuitry while the unregulated
voltage is used to drive a 12V relay coil. The operating voltage
for a 12V relay coil is typically very wide and can therefore
operate directly from the unregulated line.
Fuse
Unregulated Voltage
GN2470
120VAC
or
230VAC
Surge
Protection
1.0µF
1N4001
220µF
Gate
HVIN
Source
SR037
GND
VOUT
5.0V
1.0µF
Logic
Control
Circuit
5V Coil
Relay
1KΩ
2N3904
100Ω
Figure 5: Driving 5V Relay Coils
The circuit shown in Figure 5 uses the SR037 to supply a
regulated 5.0V for the logic control circuitry while the unregulated
voltage is used to drive a 5.0V coil relay. To overcome the voltage
variation of the unregulated line, a bipolar transistor is used to
drive the coil with a constant current. The resistor value from the
emitter to ground sets the desired coil current. For an arbitrary
coil current of 40mA, the resistor value can be calculated as:
10
B092005
SR036/SR037
Applications Information, continued
Fuse
Unregulated Voltage
GN2470
120VAC
or
230VAC
Surge
Protection
1.0µF
Vz
5.1V
220µF
Gate
HVIN
5V Coil
Relay
Source
SR037
VOUT
Logic
Control
Circuit
5.0V
1.0µF
GND
Figure 6: Driving 5V Relay Coils with Zener Diode Clamp
The circuit shown in Figure 6 uses the SR037 to supply a
regulated 5.0V for the logic control circuitry. A 5.1V Zener diode
is used in parallel with the 5.0V relay coil to ensure that the relay
coil’s maximum operating voltage is not exceeded. The Zener
Fuse
diode also acts as the catch diode when the coil is switched to the
off state. An external series resistor is used to limit the amount of
Zener current.
Unregulated Voltage
GN2470
120VAC
or
230VAC
Surge
Protection
1.0µF
220µF
Gate
HVIN
Source
SR036 or
SR037
GND
VOUT
VREG
1.0µF
330Ω
Figure 7: Driving LEDs from 120VAC
The circuit shown in Figure 7 uses the SR036 or SR037 to drive
12 high efficiency red LEDs from an AC line. The average LED
current is approximately 20mA.
B092005
11
330Ω
SR036/SR037
Applications Information, continued
Vunreg = Vz + 14V
= VLED + 8V
Fuse
R = Vunreg / 1.5mA
Vunreg
GN2470
1.0µF + 47µF
220pF
180K
VLED
Gate
HVIN
Source
Supertex
SR037
+8V
GND
Vz
PWM Dimming
(optional)
Features:
1. Precision Current Regulator
2. Zener Voltage Boost
3. PWM Dimming (optional)
4. EMI Filter (optional)
Rs
10K
Zener
Voltage
Boost
TL431
Figure 8:
Precision current drive for
LED String from AC Line
ILED
R
+2.5V
AC line
Surge
Protection
+
EMI Filter
(optional)
Constant Current
Regulator
Iled = 2.5V / Rs < 40mA
The circuit uses the SR037or SR036 and GN2470 to drive a string of LEDs from AC power line.
The LED current is regulated at up to 40mA.
The LED string voltage can be up to AC line voltage (120V for 120Vac / 230V for 230VAC).
Vunreg = VLED + 8V
< Vz + 16V
Fuse
R = Vunreg / 1.0mA
Vunreg
GN2470
1.0µF
+ 100µF
220pF
180K
AC line
Surge
Protection
+
EMI Filter
(optional)
VLED
R
Gate
HVin
Supertex
SR037
-
Source
220nF
GND
Figure 9:
Simple current drive for LED
String from AC Line
ILED
100k
Vz
Zener Boost Voltage
Limit (optional)
+
Vbe
-
Rs
Simple Current Regulator
Features:
1. Simple Current Regulator
2. Automatic Voltage Boost
3. Zener Boost Voltage Limit (optional)
4. EMI Filter (optional)
Iled = Vbe / Rs < 40mA
The circuit uses the SR037 or SR036 and GN2470 to drive a string of LEDs from AC power line.
The LED current is regulated at up to 40mA.
The LED string voltage can be up to AC line voltage (120V for 120Vac / 230V for 230VAC).
12
B092005
SR036/SR037
8-Lead MSOP Package Outline (MG)
3x3mm body, 1.10mm height (max), 0.65mm pitch
D
θ1 (x4)
8
E
E1
L2
Note 1
(Index Area
D1/2 x E1/2)
L
1
Top View
View B
A
A
Seating
Plane
θ
L1
Gauge
Plane
View B
A2
A
Seating
Plane
b
e
A1
View A-A
Side View
Note 1:
A Pin 1 identifier must be located in the index area indicated. The Pin 1 identifier may be either a mold, or an embedded metal or marked feature.
Symbol
Dimension
(mm)
MIN
A
A1
A2
b
D
E
E1
0.75
0.00
0.75
0.22
2.80
4.65
2.80
NOM
-
-
0.85
-
3.00
4.90
3.00
MAX
1.10
0.15
0.95
0.38
3.20
5.15
3.20
JEDEC Registration MO-187, Variation AA, Issue E, Dec. 2004.
Drawings not to scale.
e
0.65
BSC
L
0.40
0.60
0.80
L1
0.95
REF
L2
0.25
BSC
θ
θ1
0
5O
O
-
-
8O
15O
SR036/SR037
8-Lead SOIC (Narrow Body w/Heat Slug) Package Outline (SG)
4.90x3.90mm body, 1.70mm height (max), 1.27mm pitch
D1
D
8
θ1
8
Exposed
Thermal
Pad Zone
E
E1
Note 1
(Index Area
D/2 x E1/2)
E2
L
1
1
L1
Top View
Bottom View
A A2
A1
θ
Seating
Plane
View
B
h
Note 1
Seating
Plane
e
Gauge
Plane
View B
A
h
L2
b
A
Side View
View A-A
Note 1:
This chamfer feature is optional. If it is not present, then a Pin 1 identifier must be located in the index area indicated.The Pin 1 identifier may be either a
mold, or an embedded metal or marked feature.
Symbol
A
A1
A2
b
D
D1
E
E1
E2
MIN
Dimension
NOM
(mm)
MAX
1.25
0.00
1.25
0.31
4.80
3.30*
5.80
3.80
2.29*
-
-
-
-
4.90
-
6.00
3.90
-
1.70
0.15
1.70
0.51
5.00
3.81*
6.20
4.00
2.79*
JEDEC Registration MS-012, Variation BA, Issue E, Sept. 2005.
Dimensions marked with (*) are non-JEDEC dimensions.
Drawings not to scale.
DOC #: DSFP-SR036SR037
B092005
e
1.27
BSC
h
L
0.25
0.40
-
-
0.50
1.27
L1
L2
1.04 0.25
REF BSC
θ
θ1
0
5O
O
-
-
8O
15O
www.supertex.com
1235 Bordeaux Drive • Sunnyvale • CA • 94089 • Telephone (408) 744-0100 • Fax (408) 222-4895
Technical Bulletin: SR03x Plate Connections
This bulletin applies to the SR036 and SR037 in the SG (Power SO-8) package.
Increased efficiency and lower no-load power consumption of SR03x based regulator circuits can be
achieved by assuring no electrical connections are made to the underside plate on the SR03x package.
A copper area should still be employed to provide needed heat sinking, however, this copper area should
be electrically floating. For maximum heat sinking capability, do not cover the copper area with solder
mask.
Existing PCB layouts with the plate grounded should be corrected.
Make no electrical connections
to copper area
Solder underside plate to
copper area for heat sinking
Early SR03x demo boards erroneously had the underside plate connected to ground. These boards will
exhibit decreased efficiency and higher no load power. New, corrected demo boards may be ordered
from Supertex’s web site.
28APR03
www.supertex.com
1235 Bordeaux Drive · Sunnyvale · CA · 94089 · Telephone (408) 744-0100 · Fax (408) 222-4895
Technical Bulletin: SR03x EMI Reduction
SR03-based power supplies may create conducted EMI into the AC power line that exceeds FCC and CISPR requirements.
This bulletin describes one technique to reduce EMI, allowing SR03-based supplies to comply with applicable requirements.
Conducted EMI is largely due to the short, high-current pulse imposed on the AC line when the pass MOSFET turns on.
Smoothing out this current pulse reduces the harmonic content of the current drawn from the AC line, thus reducing
conducted EMI. Placing a simple RC filter before the MOSFET gate smoothes out the pulse.
EMI Suppressor Circuit
120/230VAC
50/60Hz
VN2460
VUNREG
P6KE
400CA
EMI
Suppressor
CG
220pF
CUNREG
220µF
RG
180kΩ
VIN
GATE
SR03x
SOURCE
GND
VREG
VREG
CREG
1µF
The values for R G and CG may need adjustment depending on the characteristics of the chosen MOSFET and the value of
CUNREG. (Higher values of CUNREG generally produce higher EMI as capacitor recharge times are shorter.) The idea is to
select values of R and C to soften the edges of the current pulse, as shown below. It may be tempting to forego C G, relying
instead on the MOSFETs’ input capacitance. However, high dV/dt when power is first applied may cause the MOSFET to turn
on due to CRSS, damaging the FET. C G protects against this possibility. Note that extending the turn-off time at the rising
edge of the rectified AC increases the voltage drop across the FET, decreasing efficiency somewhat.
AC Line Current – Turn-off Edge
500mA/div
Without EMI
Suppressor
With EMI
Suppressor
Technical Bulletin: SR03x EMI Reduction
The following spectrums show the effect of the EMI suppression technique.
120VAC/60Hz
Limits per 47CFR15.107 for Class B devices. 45mA total load.
Neutral
Average
Quasi-peak
Hot
208VAC/60Hz
(230VAC/50Hz not available) Limits per CISPR 14-1 for household appliances. 20mA total load.
Average
Quasi-peak
Live
Neutral
Technical Bulletin: SR03x EMI Reduction
The EMI reduction technique has an effect on power supply performance, as illustrated in the following graphs.
120VAC/60Hz
Efficiency
50%
Load Regulation
19
18
without EMI
suppressor
VUNREG
Efficiency
17
40%
with EMI
suppressor
30%
16
15
14
without EMI
suppressor
13
12
20%
with EMI
suppressor
11
0
10
20
30
40
50
10
0
60
IUNREG (mA)
10
20
30
40
50
60
IUNREG (mA)
208VAC/60Hz (230VAC/50Hz not available)
Efficiency
Load Regulation
40%
18
16
30%
without EMI
suppressor
VUNREG
Efficiency
17
with EMI
suppressor
20%
15
without EMI
suppressor
14
13
with EMI
suppressor
12
11
10%
0
10
20
IUNREG (mA)
30
10
0
10
20
IUNREG (mA)
30
SR03x
Technical Bulletin
SR03x Power On Surge Protection
When power is first applied to an SR03x circuit
near the peak of the input sine wave, there is an
instantaneous step of voltage at the HVIN terminal.
The same step is applied to the pass element
(MOSFET or IGBT). The parasitic capacitances in
the pass element (MOSFET or IGBT) form a
voltage divider circuit that applies an attenuated
step to the gate of the pass element in the direction
to turn on the pass element.
If the input step voltage is large enough, the pass
element will be turned on. The high impedance
gate drive of the SR03x is not strong enough to
shut down the pass element in time. The pass
element will conduct high current while there is a
large voltage across it. This over heats the pass
Power On Surge Protection Circuit Diagram
A110204
element and destroys it. In turn, the SR03x is also
destroyed.
It has been reported that this power-on circuit
destruction occurs frequently on 230VAC inputs
and occasionally on 120VAC inputs.
The protection circuit, shown below, controls the
gate drive and clamps the current through the pass
element to approximately 3 Amperes (exact current
not critical). This allows the SR03x enough time to
shut down the pass element.
As shown in the circuit diagram, the surge
protection requires only a resistor and a low cost
NPN
transistor
(MPSA06
or
equivalent).