NCP1012: 3.6 W Auxiliary Power Supply for Appliances / White Goods

DN06013/D
Design Note – DN06013/D
3.6 W Auxiliary Power Supply for Appliance/White Goods
Device
Application
Input Voltage
Output Power
Topology
I/O Isolation
NCP1012
Auxiliary supply for
Appliance / White
Goods
90 to 270 Vac
3.6 W
Flyback
Yes
Other Specifications
Output Voltage
Ripple
Nominal Current
Max Current
Min Current
Output 1
Output 2
Output 3
Output 4
12 Vdc
100 mV max
300 mA
300 mA
0A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
PFC (Yes/No)
No
Minimum Efficiency
Cooling Method/Supply
Orientation
65%
Convection
Circuit Description
Key Features
The universal AC input converter circuit is a simple
flyback regulator utilizing the monolithic NCP1012
controller (U1) with internal Mosfet to provide an isolated
12 volts at 300 mA output. Output voltage feedback is
achieved via zener diode Z1 and optocoupler U1.
Conducted EMI is attenuated by the input filter
comprised of C1 and L1. A simple inrush limiter is
provided by R1. R2, D2 and C4 is a voltage clipping
snubber that limits the peak flyback voltage to pin 3
(Mosfet drain) of U1.
August 2006, Rev. 0
y Simple yet effective off-line switcher with very few
components.
y EMI filter for conducted EMI compliance.
y Isolated output.
y Protection from overload and open optocoupler.
y Over-temperature protection.
y No auxiliary winding required on transformer for
control Vcc.
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DN06013/D
Schematic
18, 2W
AC
input
C1
R1
4.7nf
"X"
L1 1 mH
T1
D1
1N4007
1
C2
C4
C3
1 nf
1 kV
10 uF
400V
x2
MBRS160
7,8
R2
D3
150K
D2
C5B
C5A
MURS160
0.1uF
470uf
16V
x2
5,6
4
C6
+
[email protected]
_
Z1
MMSZ5241B
(11 V)
NCP1012
(SOT223,
100 kHz)
U1
3
4
R4
2
4
U2
1
68
R5
1
+ C7
10uf
25V
200
C8
100pf
3
opto 2
NOTES:
1. Zener D5 and resistor R6 sets the output voltage. Vout = Vz + 0.9 volts approximately.
2. Crossed lines are not connected.
3. Input is 90 - 265 Vac.
4. R1 is for inrush limiting.
5. U2 opto is Vishay SFH6156A or similar.
6. Pin 4 of U1 should be soldered to clad ground plane for good heatsinking.
NCP1012 Off-Line Power Supply
7. L1 is Coilcraft RFB0807-102L inductor for conducted EMI compliance.
8. See magnetics drawing for T1 details.
12 Vout @ 300 mA
9. C5B is optional for very low output ripple.
ON Semiconductor
August 2006, Rev. 0
www.onsemi.com
2
DN06013/D
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MAGNETICS DESIGN DATA SHEET
Project / Customer: ON Semiconductor - NCP1012 power supply - 3.6W
Part Description: 5 watt flyback transformer, 12 volts out
Schematic ID: T1
Core Type: EF16 (E16/8/5); 3C90 material or similar
Core Gap: Gap for 3.3 to 3.5 mH inductance
Inductance: 3.4 mH nominal
Bobbin Type: 8 pin horizontal mount for EF16
Windings (in order):
Winding # / type
Turns / Material / Gauge / Insulation Data
Primary (1 - 4)
104 turns of #35HN over 2 layers (52 TPL).
Insulate for 3 kV to the next winding.
12V Secondary (5, 6 - 7, 8)
10 turns of #28HN spiral wound over one layer with
0.12" (3mm) end margins and tape cuffed ends.
Triple insulated #28 can be subsituted without end
margins.
Vacuum varnish assembly
NOTE: Suggested Vendor: Mesa Power Systems, Escondido, CA. 1-800-515-8514
Hipot: 3 kV from boost/primary to secondary
Lead Breakout / Pinout
Schematic
(Bottom View - facing pins)
1
8
7
4
4
3
2
1
6
5
5
6
7
8
1
© 2006 ON Semiconductor.
Disclaimer: ON Semiconductor is providing this design note “AS IS” and does not assume any liability arising from its use; nor
does ON Semiconductor convey any license to its or any third party’s intellectual property rights. This document is provided only to
assist customers in evaluation of the referenced circuit implementation and the recipient assumes all liability and risk associated
with its use, including, but not limited to, compliance with all regulatory standards. ON Semiconductor may change any of its
products at any time, without notice.
Design note created by Frank Cathell, e-mail: [email protected]
August 2006, Rev. 0
www.onsemi.com
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