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. www.onsemi.com 1 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 1 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 3