DN06005/D Design Note – DN06005/D 3 Output, 10 W Off-line Power Supply Device Application Input Voltage Output Power Topology I/O Isolation NCP1014 Auxiliary off-line power supply for appliances 90 to 270 Vac 10 W Flyback Yes Other Specifications Output Voltage Ripple Nominal Current Max Current Min Current Others Output 1 Output 2 Output 3 Output 4 5V 100 mV 750 mA 1A 50 mA 12 V 100 mV 300 mA 500 mA 10 mA -5 V isolated 25 mV 250 mA 400 mA 0 N/A PFC (Yes/No) No Minimum Efficiency 68% Operating Temp Range Cooling Method/Supply Orientation 0 to +60°C N/A N/A N/A N/A Convection Isolated negative 5 volt output with tight regulation. Circuit Description Key Features This universal input, off-line switchmode power supply provides 3 mains isolated and regulated outputs. The converter circuit is a flyback based topology utilizing ON Semi’s NCP1014 monolithic switcher in an SOT-223 package. The output provides 5 and 12 volts with an additional negative 5 volt output that is isolated galvanically from the other two outputs. For simplicity, the AC input is half-wave rectified via D1 and conducted EMI is attenuated by C1 and L1. A standard bridge rectifier can be substituted if desired with lower line frequency ripple. U1 is power by an aux winding on T1 for very low standby power when the supply is unloaded. Voltage sensing, and feedback from the main 5 volt output is accomplished with a simple zener diode (Z1) and optocoupler circuit. The transformer secondary utilizes a stacked winding configuration for the 5 and 12 volt outputs which provides good cross regulation with the 5 volt output. Tight regulation is provided on the isolated – 5 volt output via a 3-terminal regulator. July 2006, Rev. 0 • • • • • • • • www.onsemi.com Useful for powering telecom, LAN, appliance and industrial controls where low power is required. Extremely simple and low cost design. 10 watt output with 12 watt surge capability with properly heatsunk SOT-223 package for U1. 90 to 270 Vac universal input range. Isolated – 5 volt output with high regulation and low output ripple. Conducted EMI filter. Half-wave input rectifier for low cost. Output short circuit protection and overvoltage protection from open optocoupler. 1 DN06005/D Schematic D1 1N4007 R1 L1, 680 uH 9 P T1 Universal AC Input N C1 0.22 uF "X2" C2 C3 33uf, 400Vdc x2 C4 1.5 nf 1 kV D5 7 10, 2W C7 MBRA160 R2 100K, 1W D4 4 8 MBR140SF D2 MURS160 10 NCP1014ST (SOT-223) U1 3 4 2 R7 680 MMSD4148A 1 D3 C11 330 16V MBRA160 6 C10 0.1 C12 U3 MC79M05 330 16V 4 C14 470 pf 3 U2 1 2 R5 47 R4 Com C13 0.1 470 Z1 1 C15 + 10 uf 25V 5V, 1A 5 D6 2 0.1 470 6.3V x2 3 12V, 300mA C9 R3 680 330 16V x2 C6 C5 C8 Rtn - 5V, 250mA iso R8 Vtrim (0 ohm) MMSZ5229B R6 180 NOTES: 1. L1 is Coilcraft RFB0807-681L 680 uH, 350 mA inductor. 2. Output common is connected to line neutral. This should be a pcb ground plane area. 3. See Magnetics Data Sheet for T1 construction details. 4. U1 is 100 kHz, SOT-223 version of NCP1014 controller. Pin 4 tab should be soldered to copper clad ground plane for best heatsinking. 5. R1 is optional inrush limiter. 6. U2 is Vishay H11A817A optocoupler or equivalent. 7. R8 is optional voltage trimming resistor - adding resistance increases Vout. 8. If full bridge input rectifier is used in place of D1, then C2 and C3 can be 22 uF, 400V caps. NCP1014 Based 10W Triple Output Power Supply ON Semiconductor Design Group July 2006, Rev. 0 www.onsemi.com 2 DN06005/D 1 MAGNETICS DESIGN DATA SHEET Project / Customer: ON Semiconductor - NCP1014 triple output supply Part Description: 10 watt flyback transformer; triple output, universal input Schematic ID: T1 Core Type: E25/10/6 (E24/25); 3C90 material or similar Core Gap: Gap for 1.45 mH nominal Inductance: L (mH) = 1.4 to 1.5 mH Bobbin Type: E24-25 PCB1-10 (10 pin horizontal pc mount) Windings (in order): Winding # / type Turns / Material / Gauge / Insulation Data Vcc (1 - 2) 7 turns of #32HN spiral wound over window with 2 mm end margins. Tape insulate to 1 kV. Selfleads to pins. Primary (10 - 9) 70 turns of #32HN over 2 layers, 35 TPL. Insulate with tape for 1 kV to next winding. Self-leads to pins. 5/12V Secondary (8 - 3, 7 - 4) 3 turns biflar of two different colors of #26HN flat wound over primary with 2 mm end margins. Continue winding 1 extra turn with one of the colors (4 turns total) - this will be the 12V winding. Self-leads to pins per diagram below. Insulate with tape for 3 kv to next winding. 9V Isolated Sec. (5 - 6) 5 turns of #26HN spiral wound over previous winding. allow 3 mm end margins. Insulate with tape. Hipot: 3 kV from primary/Vcc to 5/12/-5V secondaries for 1 minute. Lead Breakout / Pinout Schematic 9 7 (Top View) 12V sec 4 turns Pirmary 70 turns 10 1 Vcc 7 turns 2 4 8 Biflar wound plus 1 extra turn on 12v 10 9 8 7 6 5V sec 3 turns 3 5 9V sec 5 turns 12 3 4 5 Note: Rectangular hole should be cut in pc board between pins 2 - 3 and 8 - 9 to allow for proper safety creepage on secondaries. 6 Proto xfmrs available from Mesa Power Systems, Escondido, CA. 1-800-515-8514 11 © 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] July 2006, Rev. 0 www.onsemi.com 3