DN05012/D Design Note – DN05012/D A 20 to 25 Watt, Low Cost, Off-line Power Supply Device Application Input Voltage Output Power Topology I/O Isolation NCP1251B NCP431 NDD04N60 White Goods, Small Instruments, EMeters, Industrial Equipment 90 – 267 Vac 20 to 25 Watts DCM Flyback 3 kV Other Specification Output Voltage Ripple Nominal Current Max Current Min Current Output 1 Output 2 Output 3 Output 4 5Vdc or 12 Vdc < 2% 1.8 or 4 Amps 1.8 or 4 Amps zero 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 No 78% for 5Vout; 81% for 12Vout Yes 0 to 50C Convection NA No PFC (Yes/No) Minimum Efficiency Inrush Limiting / Fuse Operating Temp. Range Cooling Method / Supply Orientation Signal Level Control Others Input EMI filter Circuit Description This Design Note describes a very simple, low cost, yet high performance off-line flyback power supply using ON Semiconductor’s NCP1251B controller (TSOP6 package), NDD04N60 D-Pak Mosfet, and the NCP431 programmable zener (SOT23 package). The flyback design operates in discontinuous conduction mode and uses the conventional optocoupler (U2) feedback scheme for the voltage loop and an auxiliary Vcc winding on the flyback transformer to power the NCP1251. The Design Note provides the complete circuit and transformer design details for 5 volt, 4 amp, and 12 volt, 1.8 amp output models. Other output voltages from 3.3 up to 28 Vdc are easy to implement by modifying the values (or ratings) of R11, R12, D9, C9 and T1’s secondary turns. July 2012, Rev. 3 Over-current limiting is provided by sensing the peak current in the MOSFET Q1 via R8. Once the 800 mV threshold level on U1’s pin 4 is exceeded the circuit will go a “hiccup” mode until the over-current condition is removed. An optional OVP circuit is implemented via Z1. Depending on the application, it may be necessary to add a small pi-network ripple filter to the output as shown in the lower section of the schematic below. Key Features Input EMI filter for conducted EMI compliance Schottky output rectifier for high efficiency Very low standby (no load) power Current mode control with adjustable output current Small pc board footprint Low cost components www.onsemi.com 1 DN05012/D Schematic1 L1A F1 T1 C4 2A 250Vac C1 C2 0.1uF "X2" 0.1uF L1B "X2" AC Input R1 820uH 4.7 ohms 3W 10 D1-D4 MRA4007 X4 820uH R2 43K 1W 4.7nF 1 1kV R3 R4 470K 470K 47uF 400V Q1 D6 2 10 5 R9 1K C5 10nF 1nF 1K U1 5 1 4 R16 3K 6 0 ohms R12 39K C11 (12V) R11 1K (12V) 240 (5V) 8 C6 U3 C7 220pF 10uF 50V _ 1000uF, 16V (12Vout) 3300uF, 6.3V (5Vout) 1nF "Y1" D7 MMSD 4148 Vout 0.1uF 50V 3 R5 C10 C13 0.1 C12 R10 2 + D9 R7 R8A/B 2 ohms 1/2W 6 J2 C9A C9B 10K MMSZ5254B NCP1251B (27V) 3 MBRS360 (12V) MBRS540 (5V) R6 MRA 4007 Z1 D5 1N4937 D8 C8 EE20/10/6 9 NDD03N60Z C3 MMSD4148 J1 R15 U2 4 1 15K R14 10K 0.1 10K (5V) NCP431 R13 10K NOTES: 3 2 1. Crossed lines on schematic are NOT connected. 2. U2 is NEC PS2561L-1 or equivalent optocoupler (CTR > 50%). 3. R1 is for inrush limiting - use carbon comp or wire wound. 4. L1A/L1B are Wurth 7447728215 components (820 uH, 500mA). 5. Output caps (C9A/B) are radial lead, low impedance types (UCC LXV series or similar). 6. Z1 sets OVP trip level. 7. R5 is for Vcc trimming (< 28Vmax), typically zero ohms. 8. R8A/B sets max output current. 9. U1 is 100 kHz version 10. See drawing for T1 details. 20 Watt NCP1251 Power Supply with Universal AC Input (Rev 5A) Optional Ripple Filter J2 L2 To C10 4.7uH 5A + C13 Vout 100uF _ 1 © 2011 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 2012, Rev. 3 www.onsemi.com 2 DN05012/D MAGNETICS DESIGN DATA SHEET Project / Customer: ON Semiconductor - 20 watt, 5 Vout NCP1251 Flyback Part Description: 20 watt, 100 kHz flyback transformer, 5Vout (Wurth # 750312279) Schematic ID: T1 Core Type: EE20/10/6 ferrite core; 3C90 material or similar Core Gap: Gap for 190 +/- 200uH across Primary A (pins 1 - 10) Inductance: 750 uH total (+/- 5%) measured from pin 1 to pin 9 with pins 2 and 10 connected Bobbin Type: 10 pin horizontal mount for EE20/10/6 Windings (in order): Winding # / type Turns / Material / Gauge / Insulation Data Primary A (1 - 10) 30T of #28HN over 1 layer (30 TPL). Insulate for 1 kV to next winding. Self leads to pins. Vcc (3 - 8) 8 turns of #28 HN over 1 layer, spiral wound over primary A. Self leads to pins. Insulate to 1 kV to next winding with tape. 5V Secondary (5 - 6) 3 turns trifilar of #24 triple insulated wire over one. layer (three strands). Self leads to single pins as shown in drawing below. Primary B (2 - 9) Same as Primary A. Insulate with tape and selfleads to pins. Hipot: 3 kV from primaries & Vcc to secondary for 1 minute. Lead Breakout / Pinout Schematic 10 (Top View of Bobbin) Pri A 1 9 Pri B 2 10 9 8 7 6 5 5V sec (trifilar) 0.15" pin separation (8 places) 0.60" pin rows 6 8 1 2 3 4 5 Vcc 3 July 2012, Rev. 3 www.onsemi.com 3 DN05012/D MAGNETICS DESIGN DATA SHEET Project / Customer: ON Semiconductor - 24 watt, 12 vout NCP1251 Flyback Part Description: 24 watt flyback transformer, 12vout, 100 kHz (Wurth part # 750312495) Schematic ID: T1 Core Type: EE20/10/6 ferrite core; 3C90 material or similar Core Gap: Gap for 190 +/- 200uH across Primary A (pins 1 - 10) Inductance: 750 uH total (+/- 5%) measured from pin 1 to pin 9 with pins 2 and 10 connected Bobbin Type: 10 pin horizontal mount for EE20/10/6 Windings (in order): Winding # / type Turns / Material / Gauge / Insulation Data Primary A (1 - 10) 30T of #28HN over 1 layer (25 TPL). Insulate for 1 kV to next winding. Self leads to pins. Vcc (3 - 8) 7 turns of #28 HN over 1 layer, spiral wound over primary A. Self leads to pins. Insulate to 1 kV to next winding with tape. 12V Secondary (5 - 6) 6 turns bifilar of #24 triple insulated wire over one. layer (two strands). Self leads to pins. (Note: #26 is also acceptable here if the fit is too tight for one layer) Primary B (2 - 9) Same as Primary A. Insulate with tape and selfleads to pins. Hipot: 3 kV from primaries & Vcc to secondary for 1 minute. Lead Breakout / Pinout Schematic 10 (Top View of Bobbin) Pri A 1 9 Pri B 2 10 9 8 7 6 5 12V sec (bifilar) 0.15" pin separation (8 places) 0.60" pin rows 6 8 1 2 3 4 5 Vcc 3 July 2012, Rev. 3 2 www.onsemi.com 4 DN05012/D Efficiency Plots 12 Volt Output 5 Volt Output July 2012, Rev. 3 www.onsemi.com 5 DN05012/D Light Load (< 500mW out) and Standby (no load) Power Plots July 2012, Rev. 3 www.onsemi.com 6 DN05012/D Bill of Materials for 12Vout, 20W NCP1251 Flyback (Rev5) h 6/2/2011 Designator Qty D9 (12Vout) D9 (5Vout) Q1 D1, 2, 3, 4, 8 D5 D6, D7 Z1 U3 U2 U1 C1, C2 C12 C4 C5 C10, 11, 13 C7 C8 C3 C6 C9A, C9B (5Vout) R1 R2 R8A/B R6 R3, R4 R7, 13, 14 R11 (12Vout) R11 (5Vout) R5 R9, 10, 15 R16 R12 (12Vout) R12 (5Vout) F1 L1A/B T1 (12Vout) T1 (5Vout) J1, J2 J1, J2 1 1 1 5 1 2 1 1 1 1 2 1 1 1 3 1 1 1 1 2 2 1 1 2 1 2 3 1 1 1 3 1 1 1 1 1 1 1 2 2 Description Value Schottky diode 3A, 60V Schottky diode 5A, 40V Mosfet - NDD04N60Z 4A, 600V Diode - 60 Hz, 1A, 800V Diode - fast recov 1A, 600V Signal diode 100mA, 100V Zener diode 27V (OVP) Programmable zener 2.5V Optocoupler CTR >/= 0.5 Controller - NCP1251B 100 kHz "X" cap, box type 100nF, X2 "Y1" cap, disc type 1nF, Y1 Ceramic cap, disc 4.7nF, 1kV Ceramic cap, monolythic 1 nF, 50V Ceramic cap, monolythic 100nF, 50V Ceramic cap, monolythic 220pF, 50V Ceramic cap, monolythic 10nF, 50V Electrolytic cap 47uF, 400V Electrolytic cap 10uF, 25Vdc Electrolytic cap 1000uF, 16V Electrolytic cap 3300uF, 6.3V Resistor, 3W, Wire wound 4.7 ohm, 3W Resistor, 1W, metal film 43K, 1W Resistor, 1/2W metal film 2 ohms, 1/2W Resistor, 1/4W SMD 10 ohms Resistor, 1/4W SMD 470K Resistor, 1/4W SMD 10K Resistor, 1/4W SMD 1K Resistor, 1/4W SMD 240 ohms Resistor, 1/4W SMD Zero ohm Resistor, 1/4W SMD 1K Resistor, 1/4W SMD 3K Resistor, 1/4W SMD 39K Resistor, 1/4W SMD 10K Fuse, TR-5 style 2A Inductor (EMI choke) 820 uH, 500 mA Transformer E20/10/6 core Transformer E20/10/6 core Screw Terminal Screw Terminal Tolerance 20% 20% 5% 10% 10% 5% 5% 10% 10% 10% 10% 5% 5% 1% 1% 1% 1% 1% 1% 1% 1% 1% 1% 1% Footprint Manufacturer Manufacturer Part Number SMC SMC DPak SMA axial lead SOD-123 SOD-123 SOIC8 / SOT23 4-pin TSOP6 LS = 15 mm LS = 7.5 mm LS = 7.5 mm 1206 1206 1206 1206 LS=7.5mm, D=16mm LS=2.5mm, D=6.3mm LS=5mm, D=12.5mm LS=5mm, D=12.5mm LS=7.5mm, D=7mm Axial lead; LS=25mm Axial lead; LS=12.5mm SMD 1206 SMD 1206 SMD 1206 SMD 1206 SMD 1206 SMD 1206 SMD 1206 SMD 1206 SMD 1206 SMD 1206 TR-5, LS=5mm See Wurth Drawing See Mag Drawing See Mag Drawing LS = 0.2" LS = 0.2" ON Semi ON Semi ON Semi ON Semi ON Semi ON Semi ON Semi ON Semi Vishay or NEC ON Semi Rifa, Wima Rifa, Wima Rifa, Wima AVX, Murata AVX, Murata AVX, Murata AVX, Murata UCC, Panasonic UCC, Panasonic UCC, Panasonic UCC, Panasonic Ohmite, Dale 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 AVX, Vishay, Dale AVX, Vishay, Dale Minifuse Wurth Magnetics Wurth Magnetics Wurth Magnetics DigiKey DigiKey MBRS360T3G MBRS540T3 NDD04N60Z MRA4007 1N4937 MMSD4148A MMSZ5254B NCP431A SFH6156A-4 or PS2561L-1 NCP1251BSN100 Digi-Key P/N = 399-5426-ND Mouser P/N = 75-WKP102MCPEJ0KR Digi-Key P/N = 490-4266-ND Digi-Key P/N = 311-1170-1-ND Digi-Key P/N = 311-1179-1-ND Digi-Key P/N = 478-1484-1-ND Digi-Key P/N = 445-7688-1-ND Mouser P/N = 647-UCY2G470MHD Digi-Key P/N = 565-1055-ND Mouser P/N = 661-EKY160ELL102MK1 Newark P/N = 23K4009 Digi-Key P/N = 4.7AECT-ND Digi-Key P/N = PPC43KW-1CT-ND Mouser P/N = 660-MF1/2DCT52R2R00F Digi-Key P/N = 541-10.0FCT-ND Digi-Key P/N = 541-470KFCT-ND Digi-Key P/N = 541-10.0KFCT-ND Digi-Key P/N = 541-1.00KFCT-ND Digi-Key P/N = 541-240FCT-ND Digi-Key P/N = 541-0.0ECT-ND Digi-Key P/N = 541-1.00KFCT-ND Digi-Key P/N = 541-3.00KFCT-ND Digi-Key P/N = 541-39.0KFCT-ND Digi-Key P/N = 541-10.0KFCT-ND Newark P/N = 67K2094 7447728215 750312495 750312279 # 281-1435-ND # 281-1435-ND Substitution Allowed No No No No No No No No Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Lead Free Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Comments 12V version 5V version 12V version 5V version 12V version 5V version 12V version 5V version 12V version 5V version Blue indicates part change with Vout change 1 © 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: [email protected] July 2012, Rev. 3 www.onsemi.com 7