DN05038/D Design Note - DN05038/D Non-Isolated, 8 Watt Dual Output, Off-line Power Supply Device Application NCP1075 NST45011 White Goods, Industrial Equipment Input Voltage 180 to 270 Vac Output Power Topology I/O Isolation 8 Watts Nominal Non-Isolated Flyback No isolation from mains Other Specification Output Voltage Ripple Nominal Current Max Current Min Current Output 1 Output 2 Output 3 Output 4 5.0 Vdc +/- 2% 200 mV p/p 1A 1.25 A 1% 8.5 Vdc +/- 5% 200 mV p/p 200 mA 300 mA 1% N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A No 76% at 8 watts output Yes - limiting resistor and fuse 0 - 50 C Convection NA 68 mW @ 230 Vac PFC (Yes/No) Efficiency Inrush Limiting / Fuse Operating Temp. Range Cooling Method / Supply Orientation No Load Standby Power Others Optional high regulation sense circuit using NCP431 circuitry. Other 2nd channel voltages are possible by changing the turns of the slave secondary winding. Circuit Description This Design Note features an 8 watt, off-line, dual output, flyback power supply intended for powering white goods or industrial equipment circuitry which does not require output isolation from the AC mains. The flyback converter is designed around ON Semiconductor's 100 kHz NCP1075 monolithic switching controller. A simple voltage sensing and feedback scheme utilizing a current mirror transistor pair (Q1), and zener diode (Z1) is utilized for low cost yet effective output regulation for most typical applications. For situations requiring more precise regulation on the primary 5 volt channel (<1%), an alternate circuit using a NCP431 programmable zener as an error amplifier is shown within the dotted box in the schematic. This particular design example provides output voltages of 5V and 8.5V but these can be tailored to other voltages to accommodate the specific requirements by appropriate transformer turns ratio changes and alterations to voltage setting zener Z1 and resistor R6. The regulation loop is closed around the 5 volt main output while the 8.5 volt output is configured using a "slave" secondary winding on the transformer. The slave secondary is tightly coupled to the main 5V winding via bifilar winding techniques which assures reasonable load and cross regulation without requiring dedicated regulation October 2012, Rev. 0 Logic power (Vcc) for the control chip is derived via diode D9 directly from the slave output. Since the control IC needs a minimum of about 8 volts to maintain efficient operation, Schottky D6 is provided as an optional logic Vcc source instead of D9 in the event it is required that the second output is somewhat less than 8 volts. At Vcc voltages less than about 8 volts, the controller will operate in DSS mode and there will be some degradation in overall circuit efficiency. Although this design is for European mains voltage, a transformer design for a universal AC input version is available on request. A 5V/12V transformer design is also included in the information below. Key Features Schottky diodes (D6, D7) on both outputs for high efficiency Dual sensing options depending on desired regulation accuracy Input EMI filter for conducted emission compliance Input fuse and inrush limiting resistor (R1) Good load and cross regulation on 8.5Vout due to secondary winding technique on transformer www.onsemi.com 1 DN05038/D Schematic1 D6 D9 BAT54 MMSD 4148A D8 J1 L1A F1 L 1 mH 1A C1 AC Input 0.1uF "X" R2A C2 3.3M R1 N 6.8 ohms 2W (wire wound) D1-D4 MRA4007 X4 C3 0.1uF "X" R2B L1B R3 C4 68K 1/2W 1nF 1kV 1 mH Primary Ground Plane 7 1 6 VS2 +8.5V C11 C10 MBRS240 1000uF 16V C9A C9B 0.1uF 50V 8 VS1 +5V D5 10uF 400V U1 3.3M T1 1N4937 3 4 2 4 5 D7 C8 Com MBRS240 1500uF, 6.3V R4 1 NCP1075 (100 kHz) C5 22uF 25V 0.1uF 50V Z1 2K C6 10nF R6 C7 0.1uF Q1 NST45011 R5 MMSZ 5229B (4.3V) 100 Vtrim 120 R7 10K NOTES: R8 R9 10K 1M 1. Crossed schematic lines are not connected. 2. R4 value dependent on VS2 nominal output voltage. 3. R1 is optional inrush limiting resistor. 4. U1 tab (pin 4) should have heatsinking clad pours and be part of a ground plane area for best noise immunity. 5. Heavy lines indicate recommended ground plane areas. 6. L1A/L1B are Wurth 7447728102. 7. Z1 sets nominal 5Vout. R6 can trim Vout upward. 8. Dotted area is optional sense/error amp circuit. If selected omit Q1, Z1, R5, and R6. Z2 MMSZ 5223B (2.7V) U2 C12 0.1 NCP431 R11 4.7K R10 10K Optional Sense Amp Non-Isolated, 8 Watt, Dual Output NCP1075 PSU with Universal AC Input (Rev 7B) October 2012, Rev. 0 www.onsemi.com 2 DN05038/D MAGNETICS DESIGN DATA SHEET Project / Customer: ON Semiconductor - NCP1014/1075, 8W dual output PSU Part Description: 8 watt flyback transformer, 100kHz, 5V/9V outputs (Rev 5 - Euro version) Schematic ID: T1 Wurth Electronics Part # 750313309 Rev 02 Core Type: EF16 (E16/8/5); 3C90 material or similar Core Gap: Gap for 5.5 mH +/- 5% inductance across primary (pins 1 - 4) Inductance: 5 to 6 mH when measuring from pin 1 to pin 4 Bobbin Type: 8 pin horizontal mount for EF16 Windings (in order): Winding # / type Turns / Material / Gauge / Insulation Data Primary A (4 - 2) 78 turns of #38 mag wire wound over 1 layer. Insulate with Mylar tape for at least 1kV breakdown. 5V/8.5V Secondaries (8,5 - 7,6) 7 turns of two pieces of #26 magnet wire (different colors) spiral wound bifilar over one layer. Remove two turns so winding terminating to pins 7/6 has only 5 turns. Triple Insulated wire can also be used if desired. Self-leads to pins. Primary B (2 - 1) Same as primary A. Varnish assembly Hipot: 1 kV from primary to secondary - no agency primary/secondary insulation requirements Lead Breakout / Pinout Schematic (Bottom View - facing pins) 1 Pri B 2 8 7 5 turns (8Vstack) 6 Pri A 4 October 2012, Rev. 0 4 7 turns (5Vout) 3 2 1 5 6 7 8 5 www.onsemi.com 3 DN05038/D MAGNETICS DESIGN DATA SHEET Project / Customer: ON Semiconductor - NCP1014/1075, 8W dual output PSU Part Description: 8 watt flyback transformer, 100kHz, 5V/12V outputs (Rev 1 - Euro version) Schematic ID: T1 Core Type: EF16 (E16/8/5); 3C90 material or similar Core Gap: Gap for 5.5 mH +/- 5% inductance across primary (pins 1 - 4) Inductance: 5 to 6 mH when measuring from pin 1 to pin 4 Bobbin Type: 8 pin horizontal mount for EF16 Windings (in order): Winding # / type Turns / Material / Gauge / Insulation Data Primary A (4 - 2) 78 turns of #38 mag wire wound over 1 layer. Insulate with Mylar tape for at least 1kV breakdown. 5V/12V Secondaries (8,5 - 7,6) 7 turns of two pieces of #26 magnet wire (different colors) spiral wound bifilar over one layer. Add two more turns so the winding terminating to pins 7/6 has 9 turns total (12V stack). Triple Insulated wire can also be used if desired. Self-leads to pins. Primary B (2 - 1) Same as primary A. Varnish assembly Hipot: 1 kV from primary to secondary - no agency primary/secondary insulation requirements Lead Breakout / Pinout Schematic (Bottom View - facing pins) 1 Pri B 2 8 7 9 turns (12Vstack) 6 Pri A 4 October 2012, Rev. 0 4 7 turns (5Vout) 3 2 1 5 6 7 8 5 www.onsemi.com 4 DN05038/D Efficiency versus Pout (5V:8.5V = 2:1 Loading Ratio Respectively) 8.5 Vout Load Regulation (5 Vout set to 1A Load) October 2012, Rev. 0 www.onsemi.com 5 DN05038/D Cross Regulation (8.5Vout loaded at 100mA) Output Ripple - 5 Vout at 1 Amp Output Ripple - 8.5 Vout at 350 mA October 2012, Rev. 0 www.onsemi.com 6 DN05038/D Mosfet Drain Voltage at 150 Vac Input and 8 Watt Load Mosfet Drain Voltage at 265 Vac Input and 8 Watt Load Mosfet Drain Voltage at 260 Vac Input and 1 Watt Load October 2012, Rev. 0 www.onsemi.com 7 DN05038/D Conducted EMI Scan with 8 Watt Load (EN55022, Level B; Average) dBuV 1075 Dual 240Vac 60Hz Input 80 70 60 50 40 EN 55022; Class B Conducted, Average Average 30 20 10 0 -10 -20 1 10 10/15/2012 11:24:00 AM (Start = 0.15, Stop = 30.00) MHz PC Board Layout / Photo October 2012, Rev. 0 www.onsemi.com 8 DN05038/D Designator Qty Description Value Tolerance Substitution Lead Allowed Free Comments Footprint Manufacturer Manufacturer Part Number SMB SMA axial lead SOD-123 SOD-123 SOD-123 SOD-123 SOT-363 SOIC8 / SOT23 SOT223 ON Semi ON Semi ON Semi ON Semi ON Semi ON Semi ON Semi ON Semi ON Semi ON Semi MBRS240L (or MBRS2040L) MRA4007 1N4937 BAT54 MMSD4148A MMSZ5229B MMSZ5223B NST45011 NCP431A NCP1075ST100 No D7, D8 D1, 2, 3, 4 D5 D6 D9 Z1 Z2 Q1 U2 U1 2 4 1 1 1 1 1 1 1 1 Schottky diode Diode - 60 Hz, Diode - fast recov Schottky diode Signal diode Zener diode Zener diode Dual NPN matched xstr Programmable zener Switcher IC - NCP1075 3A, 40V 1A, 800V 1A, 600V 200mA, 30V 100mA, 100V 4.3V, 500 mA 2.7V, 500 mA 45V, 100 mA 2.5V 100 kHz C1, C2 C4 C6 C7, 8, 11 C12 C3 C10 C5 C9A, C9B 2 1 1 3 1 1 1 1 2 "X" cap, box type Ceramic cap, disc Ceramic cap, monolythic Ceramic cap, monolythic Ceramic cap, monolythic Electrolytic cap Electrolytic cap Electrolytic cap Electrolytic cap 100nF, X2 1 nF, 1kV 1 nF, 50V 100nF, 50V 100nF, 50V 10uF, 400/450V 1000uF, 16V 22uF, 25V 1,500uF, 6.3V LS = 15 mm LS = 7.5 mm 1206 1206 1206 LS=7.5mm, D=16mm LS=5 mm, D=12.5mm LS=2.5mm, D=6.3mm LS=5mm, D=12.5mm Rifa, Wima Rifa, Wima AVX, Murata AVX, Murata AVX, Murata UCC, Panasonic UCC, Panasonic UCC, Panasonic UCC, Panasonic TBD TBD TBD TBD TBD TBD TBD TBD TBD Yes 5% 10% 10% 10% 10% 10% 10% 10% R1 R3 R2A,R2B R5 R4 R9, R10 R7 R6 R8 R11 1 1 2 1 1 2 1 1 1 1 Resistor, 2W, Wire wound Resistor, 0.5W, metal film Resistor, 1/4W SMD Resistor, 1/4W SMD Resistor, 1/4W SMD Resistor, 1/4W SMD Resistor, 1/4W SMD Resistor, 1/4W SMD Resistor, 1/4W SMD Resistor, 1/4W SMD 6.8 ohm, 2W 68K, 0.5W 3.3 Meg 120 ohms 2.0K 10K 10K 100 ohms 1 Meg 4.7K 10% 10% 5% 1% 1% 1% 1% 1% 1% 1% LS=7.5mm, D=7mm Axial lead; LS=12.5mm SMD 1206 SMD 1206 SMD 1206 SMD 1206 SMD 1206 SMD 1206 SMD 1206 SMD 1206 Ohmite, Dale Ohmite, Dale AVX, Vishay, Dale AVX, Vishay, Dale AVX, Vishay, Dale AVX, Vishay, Dale AVX, Vishay, Dale AVX, Vishay, Dale AVX, Vishay, Dale AVX, Vishay, Dale TBD TBD TBD TBD TBD TBD TBD TBD TBD TBD Yes F1 L1A/B T1 (5/8.5Vout J1 1 1 1 1 Fuse, TR-5 style Inductor (EMI choke) Transformer Screw Terminal TR-5, LS=5mm See Wurth Drawing See Mag Drawing LS = 0.2" Minifuse LS=5mm, D=8mm Wurth Magnetics DigiKey 7447728102 750313309 Rev 02 # 281-1435-ND 1A 1 mH, 500 mA E20/10/6 core www.onsemi.com No No No For 12Vout and higher No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yellow indicates parts for standard Vout sense scheme Green indicates parts for alternate Vout sense scheme. October 2012, Rev. 0 No 9 12V version DN05038/D References: NCP1075 data sheet: http://www.onsemi.com/pub_link/Collateral/NCP1072-D.PDF NCP1075 Design Note: http://www.onsemi.com/pub_link/Collateral/DN05018-D.PDF NCP1072 EVAL Board Documents: http://www.onsemi.com/PowerSolutions/supportDoc.do?type=boards&rpn=NCP1072 1 (c) 2012 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: f.cathell@onsemi.com October 2012, Rev. 0 www.onsemi.com 10