DN06034/D DN06034/D Universal Input, +/- 12 V Output 8 Watt PSU Device Application Input Voltage Output Power Topology I/O Isolation NCP1014 Power Supply 90 – 275 Vac 8 Watts nominal DCM Flyback Yes – 3kV Other Specifications Output Voltage Ripple Nominal Current Max Current Min Current Output 1 Output 2 Output 3 Output 4 +12 Vdc 100 mV pk 500 mA 650 mA 450 mA -12 Vdc 100 mV pk 100 mA 250 mA 50 mA 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 75% at full load Inrush Limiting / Fuse Yes – both included Operating Temp. Range Cooling Method/Supply Orientation 0 to +60°C Convection Circuit Description Key Features This 8 watt, dual output (+/- 12 volts), off-line power supply is designed around a flyback converter topology utilizing ON Semiconductor’s NCP1014 monolithic controller with integrated high voltage Mosfet. The flyback converter is operated in discontinuous conduction mode (DCM) for minimal EMI generation and to enhance simplicity and compactness in the flyback transformer design (T1). An auxiliary winding on the transformer powers the control circuit after turn on which maximizes overall conversion efficiency. The outputs are regulated by sensing the summed voltage of both the -12 and +12 volt outputs. This assures very good regulation on both channels. A very simple yet effective zener (Z1) and optocoupler (U2) feedback scheme is used for maximum simplicity and low cost. The flyback transformer is designed utilizing an industry standard EF16 ferrite core with straightforward winding techniques. Details of critical components and other circuit layout information are located in the “Notes” block on the schematic below. November 2007, Rev. 0 Common and differential mode EMI input filter for low conducted emissions. Inherent over-current and over-voltage protection on both outputs. Schottky output rectifiers for high efficiency. Summed output voltage sensing for tight regulation on both outputs. Output surge capability to over 10 watts. Input current inrush limiting (R1) Universal AC input www.onsemi.com 1 DN06034/D Schematic F1 1A L1 90 270 Vac C2 C1 0.1 "X" R1 5.1 ohms, 2W R2 1M 0.5W D1 - D4 MRA4007 1 0.1 "X" C4 1nF 3kV C3 47uF 400V T1 5 R3 75K 1W MBRS160T 6 7 D8 D5 MRA4007 D6 470uF, 25V x 2 D7 4 3 8 C9 C8 R8 20K C11 C12 470uF, 25V x 2 MBRS160T C10 0.1 R7 10K C13 0.1 12V, 500 mA Com -12V, 100 mA 1N4148 R4 (510) 2 C7 2.2 nF "Y" NCP1014 (SOT223 100 kHz) Z1 24V 3 R5 U1 4 2 4 1 + C5 22uF 25V U2 1 R6 330 C6 1nF 47 3 opto 2 Notes: 1. Crossed lines on schematic are not connected. 2. U2 is Vishay H11A817A optocoupler or equivalent. 3. L1 is Coilcraft BU16-4530R5BL or similar CM EMI inductor. 4. Z1 sets output level: Vout = (Vz + 0.85V)/2 5. U1 pin 4 tab should be soldered to clad for heatsinking. 6. R4 may need adjustment for startup/OVP optimization. 7. See magnetics design for T1 details. November 2007, Rev. 0 www.onsemi.com Triple Output, 8 Watt, Off-line Power Supply based on NCP1014 Controller ON Semiconductor Design Group 2 DN06034/D 1 MAGNETICS DESIGN DATA SHEET Project / Customer: Schneider - NCP1014 dual output supply (+/- 12V) Part Description: 8 watt, 100 kHz flyback transformer; +/- 12V output, universal input Schematic ID: T1 Core Type: EF16 (E16/8/5); 3C90 material or similar Core Gap: Gap for 1.4 to 1.6 mH Inductance: L = 1.5 mH +/- 5% nominal Bobbin Type: 8 pin horizontal mount for EF16 Windings (in order): Winding # / type Turns / Material / Gauge / Insulation Data Vcc/Aux (3 - 2) 8 turns of #35HN spiral wound over 1 layer. Selfleads to pins. Insulate with tape for 1 kV to next winding. Primary (4 - 1) 100 turns of #35HN over 2 layers, 50 TPL. Insulate with tape for 3 kV to next winding. Self-leads to pins. +12/-12V Secondary (5 - 6, 7 - 8) 8 turns wound biflar of two different colors of #26HN flat wound over 1 layer with winding ends cuffed with tape. Self-leads to pins per diagram below. Insulate with final layer of tape. Vacuum varinish assembly. Hipot: 3 kV from boost/primary to secondaries for 1 minute. Lead Breakout / Pinout Schematic (Bottom View - facing pins) 1 5 Pri +12V 6 4 7 3 -12V Vcc Bifilar wind 4 3 2 1 5 6 7 8 8 2 11 © 2007 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] November 2007, Rev. 0 www.onsemi.com 3