Design Example Report Title 15 W Power Supply with <30 mW No-load Input Power Using TinySwitch-III (TNY278P) Specification 85 VAC – 265 VAC Input; 12 V, 1.25 A Output Application TinySwitch-III Reference Design Author Applications Engineering Department Document Number DER-228 Date July 23, 2009 Revision 1.0 Summary and Features • • • • • EcoSmart® – Meets all existing and proposed harmonized energy efficiency standards including: CECP (China), CEC, EPA, AGO, European Commission • No-load consumption < 30 mW at 230 VAC • > 81% active-mode efficiency • Exceeds ENERGY STAR v2 / EuP tier 2 requirements of 79% BP/M capacitor value selects MOSFET current limit for greater design flexibility Tightly toleranced I2f parameter (–10%, +12%) reduces system cost: • Increases MOSFET and magnetics power delivery • Reduces overload power, which lowers output diode and capacitor costs Integrated TinySwitch-III Safety/Reliability features: • Accurate (± 5%), auto-recovering, hysteretic thermal shutdown function maintains safe PCB temperatures under all conditions • Auto-restart protects against output short circuit and open loop fault conditions • > 3.2 mm creepage on package enables reliable operation in high humidity and high pollution environments Meets EN550022 and CISPR-22 Class B conducted EMI with >12 dB margin PATENT INFORMATION The products and applications illustrated herein (including transformer construction and circuits external to the products) may be covered by one or more U.S. and foreign patents, or potentially by pending U.S. and foreign patent applications assigned to Power Integrations. A complete list of Power Integrations' patents may be found at www.powerint.com. Power Integrations grants its customers a license under certain patent rights as set forth at <http://www.powerint.com/ip.htm>. Power Integrations 5245 Hellyer Avenue, San Jose, CA 95138 USA. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com DER-228 - 15 W, 12 V Supply with <30 mW No-load Input Power 23-Jul-09 Table of Contents 1 2 3 4 Introduction.................................................................................................................4 Power Supply Specification ........................................................................................6 Circuit Diagram...........................................................................................................7 Circuit Description ......................................................................................................8 4.1 Input Rectification and Filtering ...........................................................................8 4.2 TNY278PN Operation .........................................................................................8 4.3 Bias Winding Design ...........................................................................................9 4.4 Output Rectification and Filtering ........................................................................9 4.5 Feedback and Output Voltage Regulation...........................................................9 4.6 EMI Design Aspects ............................................................................................9 4.7 Peak Primary Current Limit Selection..................................................................9 5 PCB Layout ..............................................................................................................11 6 Bill of Materials .........................................................................................................12 7 Transformer Specification.........................................................................................13 7.1 Electrical Diagram .............................................................................................13 7.2 Electrical Specifications.....................................................................................13 7.3 Materials............................................................................................................14 7.4 Transformer Build Diagram ...............................................................................14 7.5 Transformer Construction..................................................................................15 8 Transformer Design Spreadsheet.............................................................................16 9 Performance Data ....................................................................................................18 9.1 Active Mode Efficiency ......................................................................................18 9.2 Energy Efficiency Requirements .......................................................................19 9.2.1 USA Energy Independence and Security Act 2007 ....................................20 9.2.2 ENERGY STAR EPS Version 2.0 ..............................................................20 9.3 No-load Input Power..........................................................................................21 9.4 Available Output Power vs Input Power (230 VAC)...........................................22 9.5 Available Standby Output Power.......................................................................23 9.6 Regulation .........................................................................................................24 9.6.1 Load and Line ............................................................................................24 10 Thermal Performance ...........................................................................................25 11 Waveforms............................................................................................................26 11.1 Drain Voltage and Current, Normal Operation...................................................26 11.2 Output Voltage Start-Up Profile .........................................................................27 11.3 Drain Voltage and Current Start-Up Profile .......................................................27 11.4 Load Transient Response (75% to 100% Load Step) .......................................28 11.5 Output Ripple Measurements............................................................................29 11.5.1 Ripple Measurement Technique ................................................................29 11.5.2 Measurement Results ................................................................................30 12 Conducted EMI .....................................................................................................31 12.1 115 VAC, Full Load ...........................................................................................31 12.2 230 VAC, Full Load ...........................................................................................32 13 Revision History ....................................................................................................33 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 2 of 34 23-Jul-09 DER-228 - 15 W, 12 V Supply with <30 mW No-load Input Power Important Note: Although this board was designed to satisfy safety isolation requirements, it has not been agency approved. Therefore, all testing should be performed using an isolation transformer to provide the AC input to the power supply. Page 3 of 34 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com DER-228 - 15 W, 12 V Supply with <30 mW No-load Input Power 23-Jul-09 1 Introduction This report describes a universal input, 12 V, 1.25 A flyback power supply using a TNY278P device from the TinySwitch-III family of ICs. The goal of the design was to demonstrate the very low no-load input power that is achievable with TinySwitch-III devices AC AC + - + Figure 1 – DER-228 Populated Circuit Board Photographs (3.2 × 1.8 inches). Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 4 of 34 23-Jul-09 DER-228 - 15 W, 12 V Supply with <30 mW No-load Input Power The design was based on the EP91 reference design board with the only changes being optimization of the bias winding components that supply the operating current into the BYPASS pin of the TNY278P IC and changing the output diode from a PN ultra fast to Schottky barrier type. The report contains the complete specification of the power supply, a detailed circuit diagram, the entire bill of materials required to build the supply, extensive documentation of the power transformer, along with test data and oscillographs of the most important electrical waveforms. The board provides a number of user configurable options which are designed to demonstrate the features and flexibility of the TinySwitch-III family. These include easy adjustment of the device current limit for increased output power or higher efficiency operation, and a latched output overvoltage shutdown. Page 5 of 34 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com DER-228 - 15 W, 12 V Supply with <30 mW No-load Input Power 23-Jul-09 2 Power Supply Specification The table below represents the minimum acceptable performance of the design. Actual performance is listed in the results section. Description Input Voltage Frequency No-load Input Power (230 VAC) Output Output Voltage Output Ripple Voltage Output Current Total Output Power Continuous Output Power Efficiency Full Load Required average efficiency at 25, 50, 75 and 100 % of POUT Symbol Min VIN fLINE 85 47 11 Typ Max Units Comment VAC Hz W 2 Wire – no P.E. 50/60 265 64 0.03 13 100 12 w/o UVLO resistor or bias winding VOUT VRIPPLE IOUT 1.25 V mV A POUT 15 W η 81 % Measured at POUT 25 C ηES2 ηEuP 79 % Per Energy Star 2.0 standard ± 8% 20 MHz bandwidth o Environmental Conducted EMI Meets CISPR22B / EN55022B Safety Designed to meet IEC950, UL1950 Class II Board size 3.2 x 1.8 81.3 x 45.7 Ambient Temperature TAMB 0 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com 40 Inches mm o C Length x width Free convection, sea level Page 6 of 34 23-Jul-09 DER-228 - 15 W, 12 V Supply with <30 mW No-load Input Power 3 Circuit Diagram Figure 2 – DER-228 Circuit Diagram. Page 7 of 34 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com DER-228 - 15 W, 12 V Supply with <30 mW No-load Input Power 23-Jul-09 4 Circuit Description This flyback power supply was designed around the TNY278PN (U1 in Figure 2). The output voltage is sensed and fed back to U1 through optocoupler U2. The feedback signal is used to maintain constant voltage (CV) regulation of the output via ON/OFF control. 4.1 Input Rectification and Filtering Diodes D1–D4 rectify the AC input. Capacitors C1 and C2 filter the rectified DC. Inductor L1, C1 and C2 form a pi filter that attenuates differential mode conducted EMI. 4.2 TNY278PN Operation The TNY278PN device (U1) integrates an oscillator, a switch controller, startup and protection circuitry, and a power MOSFET, all on one monolithic IC. One side of the power transformer (T1) primary winding is connected to the positive leg of C2, and the other side is connected to the DRAIN pin of U1. At the start of a switching cycle, the controller turns the MOSFET on and current ramps up in the primary winding, which stores energy in the core of the transformer. When that current reaches the current limit threshold, the controller turns the MOSFET off. Due to the phasing of the transformer windings and the orientation of the output diode, the stored energy then induces a voltage across the secondary winding, which forward biases the output diode, and the stored energy is delivered to the output capacitor. During MOSFET turns off, the leakage inductance of the transformer induces a voltage spike on the drain node. The amplitude of that spike is limited by an RCDZ clamp network that consists of D5, C4, R2, R1 and VR1. Resistor R2 also limits the reverse current that flows through D5 when the MOSFET turns on. This allows a slow, low-cost, glass passivated diode (with a recovery time of ≤2 µs.) to be used for D5, which improves conducted EMI and efficiency. Alternately a fast diode like that FR106 may be used in place of D5 with a slight reduction in efficiency. Using ON/OFF control, U1 skips switching cycles to regulate the output voltage, based on feedback to its EN/UV pin. The EN/UV pin current is sampled, just prior to each switching cycle, to determine if that switching cycle should be enabled or disabled. If the EN/UV pin current is <115 µA, the next switching cycle begins, and is terminated when the current through the MOSFET reaches the internal current limit threshold. To evenly spread switching cycles, preventing group pulsing, the EN pin threshold current is modulated between 115 µA and 60 µA based on the state during the previous cycle. A state-machine within the controller adjusts the MOSFET current limit threshold to one of four levels, depending on the load being demanded from the supply. As the load on the supply drops, the current limit threshold is reduced. This ensures that the effective switching frequency stays above the audible range until the transformer flux density is Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 8 of 34 23-Jul-09 DER-228 - 15 W, 12 V Supply with <30 mW No-load Input Power low. When the standard production technique of dip varnishing is used for the transformer, audible noise is practically eliminated. 4.3 Bias Winding Design Although a bias winding is not necessary for the operation of the TinySwitch-III family, its use greatly reduces the no load consumption of a power supply. During steady state operation the bias winding supplies the IC bias current. Resistors R3 and R8 were adjusted to minimize the no-load input power by providing the supply current required by U1 at no-load. 4.4 Output Rectification and Filtering Diode D7 rectifies the output of T1. A schottky barrier type was selected to improve efficiency. Output voltage ripple was minimized by using a low ESR capacitor for C10 (see Section 6 for component part numbers and values). A post filter (ferrite bead L2 and C11) attenuates the high frequency switching noise. 4.5 Feedback and Output Voltage Regulation The supply’s output voltage regulation set-point is set by the voltage that develops across Zener diode VR3, R6 and the LED in opto-coupler U2. Resistor R6 limits the maximum current through U2 during load transients. The value of resistor R6 can be varied slightly to fine-tune the output regulation set point. When the output voltage rises above the set point, the LED in U2 becomes forward biased. On the primary side, the photo-transistor of U2 turns on and draws current out of the EN/UV pin of U1. Just before the start of each switching cycle, the controller checks the EN/UV pin current. If the current flowing out of the EN/UV pin is greater than 115 µA, that switching cycle will be disabled. As switching cycles are enabled and disabled, the output voltage is kept very close to the regulation set point. For greater output voltage regulation accuracy, a reference IC such as a TL431 can be used in place of Zener diode VR3. 4.6 EMI Design Aspects An input pi filter (C1, L1 and C2) attenuates conducted, differential mode EMI noise. Shielding techniques (E-Shield™) were used in the construction of T1 to reduce common mode EMI displacement currents. When combined with the IC’s frequency jitter function, these techniques produce excellent conducted EMI performance. 4.7 Peak Primary Current Limit Selection The value of the capacitor installed on the BP/M pin allows the current limit of U1 to be selected. The power supply designer can change the current limit of the MOSFET by simply changing the capacitance value connected to the BP/M pin (see the TinySwitch-III data sheet for more details). Installing a 0.1 µF capacitor on the BP/M pin selects the standard current limit of the IC, and is the normal choice for enclosed adapter applications. Page 9 of 34 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com DER-228 - 15 W, 12 V Supply with <30 mW No-load Input Power 23-Jul-09 Installing a 1 µF capacitor on the BP/M pin reduces the MOSFET current limit, which lowers conduction losses and improves efficiency (at the expense of reducing the maximum power capability of the IC). A 10 µF capacitor on the BP/M pin will raise the MOSFET current limit and extend the power capability of the IC (for higher power applications that do not have the thermal constraints of an enclosed adapter, or to supply short-duration, peak load demands). The DER-228 board comes with a 0.1 µF capacitor installed as C7, which causes U1 to select the standard current limit specified in the TinySwitch-III data sheet. If C7 were replaced by a 1 µF capacitor (C8 in the BOM, section 6), the current limit of U1 would be the same as the standard current limit for a TNY277 device. If a 10 µF capacitor is installed, the current limit of U1 will be the same as the standard current limit for a TNY279 device. The flexibility of this option enables the designer to do three things. First, it allows the designer to measure the effect of switching to an adjacent device without actually removing and replacing the IC. Second, it allows a larger device to be used with a lower current limit, for higher efficiency. Third, it allows a smaller device to be used with a higher current limit in a design when higher power is not required on a continual basis, which effectively lowers the cost of the supply. Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 10 of 34 23-Jul-09 DER-228 - 15 W, 12 V Supply with <30 mW No-load Input Power 5 PCB Layout Figure 3 – Printed Circuit Board Layout (3.2 × 1.8 inches). Page 11 of 34 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com DER-228 - 15 W, 12 V Supply with <30 mW No-load Input Power 23-Jul-09 6 Bill of Materials Item 1 Qty 1 Ref Des C1 2 1 C2 3 4 1 1 C4 C5 22 µF, 400 V, Electrolytic, Low ESR, 901 mΩ, (16 x 20) OBSOLETE not RoHS compliant see 20-0063400 10 nF, 1 kV, Disc Ceramic 2.2 nF, Ceramic, Y1 5 1 C6 33 µF, 35 V, Electrolytic, Very Low ESR, 300 mΩ, (5 x 11) 6 1 C7 7 1 C10 8 1 9 4 C11 D1 D2 D3 D4 Description 22 µF, 400 V, Electrolytic, High Ripple, (12.5 x 25) Mfg Panasonic Mfg Part Number EEU-EB2G220 Nippon Chemi-Con EKMX401ELL220ML20S Vishay Vishay 5HKMS10 440LD22-R Nippon Chemi-Con EKZE350ELL330ME11D 100 nF, 50 V, Ceramic, X7R 1000 µF, 25 V, Electrolytic, Very Low ESR, 21 mΩ, (12.5 x 20) 100 µF, 25 V, Electrolytic, Very Low ESR, 130 mΩ, (6.3 x 11) Epcos B37987F5104K000 Nippon Chemi-Con EKZE250ELL102MK20S Nippon Chemi-Con EKZE250ELL101MF11D 1000 V, 1 A, Rectifier, DO-41 Vishay 1N4007 Vishay 1N4007GP 10 1 D5 1000 V, 1 A, Rectifier, Glass Passivated, 2 µs, DO-41 11 12 1 1 D6 D7 200 V, 1 A, Ultrafast Recovery, 50 ns, DO-41 80 V, 3 A, Schottky, DO-201AD Vishay Vishay UF4003-E3 SB380 13 14 15 16 17 18 1 2 1 1 1 1 F1 J1 J4 J2 J3 JP1 L1 Wickman Keystone Keystone Keystone Alpha 37013150410 5011 5012 5010 298 HTB2-102-281 19 1 L2 3.15 A, 250V,Fast, TR5 Test Point, BLK,THRU-HOLE MOUNT Test Point, WHT,THRU-HOLE MOUNT Test Point, RED,THRU-HOLE MOUNT Wire Jumper, Non insulated, 22 AWG, 0.7 in 1mH, 350m A 3.5 mm x 7.6 mm, 75 Ω at 25 MHz, 22 AWG hole, Ferrite Bead Fair-Rite 2743004112 20 21 22 23 24 25 26 1 1 1 1 1 1 1 R1 R2 R3 R6 R7 R8 RV1 1 kΩ, 5%, ¼ W, Carbon Film 100 Ω, 5%, 1/4 W, Carbon Film 47 Ω, 5%, 1/8 W, Carbon Film 390 Ω, 5%, 1/8 W, Carbon Film 1 Ω, 5%, 1/4 W, Carbon Film 8.06 kΩ, 1/4 W, Metal Film 275 V, 45 J, 10 mm, RADIAL CFR-25JB-1K0 CFR-25JB-100R CFR-12JB-47R CFR-12JB-390R CFR-25JB-1R0 MFR-25FBF-8K06 V275LA10 27 28 29 30 31 1 1 1 1 1 T1 U1 U2 VR1 VR3 Transformer, 10 Pins, Vertical TinySwitch-III, TNY278PN, DIP-8C Opto coupler, 80 V, CTR 80-160%, 4-DIP 150 V, 6005 W, 5%, TVS, DO204AC (DO-15) 11 V, 500 mW, 5%, DO-35 Yageo Yageo Yageo Yageo Yageo Yageo Littlefuse Yih-Hwa Enterprises Power Integrations NEC Littlelfuse Vishay YW-360-02B TNY278PN PS2501-1-H-A P6KE150A BZX55-C11 * Optional components Note – All parts are RoHS compliant Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 12 of 34 23-Jul-09 DER-228 - 15 W, 12 V Supply with <30 mW No-load Input Power 7 Transformer Specification 7.1 Electrical Diagram NC Cancellation 15T # 30 AWG X2 WDG # 1 Primary WDG # 2 8 1 Secondary WDG # 5 7T # 26 T.I.W 30T # 30 AWG 6 3 4 Bias WDG # 3 6T # 26 AWG X3 5 Figure 4 – Transformer Electrical Diagram. 7.2 Electrical Specifications Electrical Strength Primary Inductance Resonant Frequency Primary Leakage Inductance Page 13 of 34 1 second, 60 Hz, from pins 1-5 to pins 6-10 Pins 1-3, all other windings open, measured at 100 kHz, 0.4 V RMS Pins 1-3, all other windings open Pins 1-3, with pins 6-8 shorted, measured at 100 kHz, 0.4 V RMS 3000 VAC 1170 µH, ±10% 500 kHz (Min.) 50 µH (Max.) Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com DER-228 - 15 W, 12 V Supply with <30 mW No-load Input Power 7.3 Materials Item [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] 7.4 23-Jul-09 Description Core: PC40EE25-Z, TDK or equivalent gapped for AL of 323 nH/T2 Bobbin: EE25, Vertical, 10 pin – Yih-Hwa part # YW-360-02B Magnet Wire: #30 AWG Magnet Wire: #26 AWG Triple Insulated Wire: #26 AWG. Tape: 3M # 44 Polyester web. 2.0 mm wide Tape: 3M 1298 Polyester Film, 2.0 mils thick, 8.6 mm wide Tape: 3M 1298 Polyester Film, 2.0 mils thick, 10.7 mm wide Tape: 3M 1298 Polyester Film, 2.0 mils thick, 4.0 mm wide Varnish (applied by dipping only, not vacuum impregnation) Transformer Build Diagram 6 8 2 mm 1 Layer of Tape 5 Bias Winding 4 1 3 1 2 mm Primary Winding Margin 1 Layer of Tape Tape Cancellation Winding No Connect Figure 5 – Transformer Build Diagram. Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 14 of 34 23-Jul-09 7.5 DER-228 - 15 W, 12 V Supply with <30 mW No-load Input Power Transformer Construction Bobbin Set Up Orientation Margin Tape WD1 Cancellation Winding Insulation WD#2 Primary winding Insulation WD #3 Bias Winding Insulation Margin Tape WD #5 Secondary Winding Outer Insulation Core Assembly Varnish Page 15 of 34 Set up the bobbin with its pins oriented to the left hand side. Apply 2.0 mm margin at the pin side of bobbin using item [6]. Match combined height of shield, primary, and bias windings. Start at Pin 1. Wind 15 bifilar turns of item [3] from left to right. Wind with tight tension across entire bobbin evenly. Cut the ends of the bifilar and leave floating. 1 Layer of tape [7] for insulation. Start at pin 3. Wind 30 turns of item [3] from left to right. Apply 1 Layer of tape [7] for insulation. Wind another 30 turns from right to left. Wind with tight tension across entire bobbin evenly. Finish at pin 1. 1 Layer of tape [7] for insulation. Start at pin 4, wind 6 trifilar turns of item [5]. Wind from left to right with tight tension. Wind uniformly, in a single layer across entire width of bobbin. Finish on pin 5. 1 Layer of tape [8] for insulation. Apply 2.0 mm margin at the pin side of bobbin using item [6]. Match combined height of secondary windings. Start at pin 8, wind 7 turns of item [5] from left to right. Wind uniformly, in a single layer across entire bobbin evenly. Finish on pin 6. 3 Layers of tape [8] for insulation. Assemble and secure core halves using item [1] and item [9]. Dip varnish using item [10] (do not vacuum impregnate.) Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com DER-228 - 15 W, 12 V Supply with <30 mW No-load Input Power 23-Jul-09 8 Transformer Design Spreadsheet ACDC_TinySwitch-III _032608; Rev.1.26; Copyright Power Integrations 2008 INPUT ENTER APPLICATION VARIABLES VACMIN 85 VACMAX 265 fL 50 VO 12.00 IO 1.25 Power n 0.82 Z 0.50 tC CIN 3.00 44.00 INFO OUTPUT Volts Volts Hertz Volts Amps 15 ENTER TinySwitch-III VARIABLES TinySwitch-III TNY278 Chosen Device Chose Configuration STD ILIMITMIN ILIMITTYP ILIMITMAX fSmin I^2fmin UNIT 44 Minimum AC Input Voltage Maximum AC Input Voltage AC Mains Frequency Output Voltage (at continuous power) Power Supply Output Current (corresponding to peak power) Watts Continuous Output Power Efficiency Estimate at output terminals. Under 0.7 if no better data available Z Factor. Ratio of secondary side losses to the total losses in the power supply. Use 0.5 if no better data available mSeconds Bridge Rectifier Conduction Time Estimate uFarads Input Capacitance TNY278 User defined TinySwitch-III TNY278 Standard Current Limit 0.512 0.550 0.588 124000 35.937 Amps Amps Amps Hertz A^2kHz VOR 108.00 108 Volts VDS VD KP 0.55 10 0.55 0.64 Volts Volts KP_TRANSIENT 0.37 ENTER BIAS WINDING VARIABLES VB 11 VDB NB VZOV 11.00 0.70 6.14 17.00 Volts Volts UVLO VARIABLES V_UV_TARGET 92.00 Volts V_UV_ACTUAL 92.20 Volts RUV_IDEAL RUV_ACTUAL 3.59 3.60 Mohms Mohms 92 ACDC_TinySwitch-III_032608_Rev1-26.xls; TinySwitch-III Continuous/Discontinuous Flyback Transformer Design Spreadsheet ENTER TRANSFORMER CORE/CONSTRUCTION VARIABLES Core Type EE25 EE25 Core EE25 Bobbin EE25_BO BBIN AE 0.404 LE 7.34 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Enter "RED" for reduced current limit (sealed adapters), "STD" for standard current limit or "INC" for increased current limit (peak or higher power applications) Minimum Current Limit Typical Current Limit Maximum Current Limit Minimum Device Switching Frequency I^2f (product of current limit squared and frequency is trimmed for tighter tolerance) Reflected Output Voltage (VOR < 135 V Recommended) TinySwitch-III on-state Drain to Source Voltage Output Winding Diode Forward Voltage Drop Ripple to Peak Current Ratio (KP < 6) Transient Ripple to Peak Current Ratio. Ensure KP_TRANSIENT > 0.25 Volts Bias Winding Voltage Bias Winding Diode Forward Voltage Drop Bias Winding Number of Turns Over Voltage Protection zener diode voltage. Target DC under-voltage threshold, above which the power supply with start Typical DC start-up voltage based on standard value of RUV_ACTUAL Calculated value for UV Lockout resistor Closest standard value of resistor to RUV_IDEAL P/N: Enter Transformer Core P/N: EE25_BOBBIN cm^2 cm Core Effective Cross Sectional Area Core Effective Path Length Page 16 of 34 23-Jul-09 DER-228 - 15 W, 12 V Supply with <30 mW No-load Input Power AL BW M 1.00 1420 10.2 1 L NS 2.00 7 2 7 DC INPUT VOLTAGE PARAMETERS VMIN VMAX 93 375 CURRENT WAVEFORM SHAPE PARAMETERS DMAX 0.57 nH/T^2 mm mm Volts Volts Minimum DC Input Voltage Maximum DC Input Voltage Duty Ratio at full load, minimum primary inductance and minimum input voltage Average Primary Current Minimum Peak Primary Current Primary Ripple Current Primary RMS Current IAVG IP IR IRMS TRANSFORMER PRIMARY DESIGN PARAMETERS LP 0.22 0.51 0.33 0.31 Amps Amps Amps Amps 1170 uHenries LP_TOLERANCE NP ALG BM 10 60 323 2828 10.00 BAC 905 ur LG BWE OD 2053 0.12 16.4 0.27 INS 0.05 DIA AWG 0.22 32 CM CMA 64 205 Ungapped Core Effective Inductance Bobbin Physical Winding Width Safety Margin Width (Half the Primary to Secondary Creepage Distance) Number of Primary Layers Number of Secondary Turns Typical Primary Inductance. +/- 10% to ensure a minimum primary inductance of 1064 Uh % Primary inductance tolerance Primary Winding Number of Turns nH/T^2 Gapped Core Effective Inductance Gauss Maximum Operating Flux Density, BM<3000 is recommended Gauss AC Flux Density for Core Loss Curves (0.5 X Peak to Peak) Relative Permeability of Ungapped Core mm Gap Length (Lg > 0.1 mm) mm Effective Bobbin Width mm Maximum Primary Wire Diameter including insulation mm Estimated Total Insulation Thickness (= 2 * film thickness) mm Bare conductor diameter AWG Primary Wire Gauge (Rounded to next smaller standard AWG value) Cmils Bare conductor effective area in circular mils Cmils/Amp Primary Winding Current Capacity (200 < CMA < 500) TRANSFORMER SECONDARY DESIGN PARAMETERS Lumped parameters ISP 4.41 Amps Peak Secondary Current ISRMS IRIPPLE CMS AWGS 2.35 1.99 470 23 Amps Amps Cmils AWG Secondary RMS Current Output Capacitor RMS Ripple Current Secondary Bare Conductor minimum circular mils Secondary Wire Gauge (Rounded up to next larger standard AWG value) 622 Volts Maximum Drain Voltage Estimate (Assumes 20% zener clamp tolerance and an additional 10% temperature tolerance) VOLTAGE STRESS PARAMETERS VDRAIN Page 17 of 34 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com DER-228 - 15 W, 12 V Supply with <30 mW No-load Input Power 23-Jul-09 9 Performance Data The ON/OFF control scheme employed by TinySwitch-III yields virtually constant efficiency across the 25% to 100% load range required for compliance with ENERGY STAR and EuP energy efficiency standards for external power supplies (EPS). Even at loads below 10% of the supply’s full rated output power, efficiency remains above 75%, providing excellent standby performance for applications that require it. This performance is automatic with ON/OFF control. There are no special burst modes that require the designer to consider specific thresholds within the load range in order to achieve compliance with global energy efficiency standards. All measurements performed at room temperature, 60 Hz input frequency. 9.1 Active Mode Efficiency 85 265 V 230 V 115 V 85 V Efficiency(%) 83 81 79 77 75 0 0.125 0.25 0.375 0.5 0.625 0.75 0.875 1 1.125 1.25 Output Current (A) Figure 6 – Efficiency vs. Output Current, Room Temperature, 60 Hz.. Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 18 of 34 23-Jul-09 DER-228 - 15 W, 12 V Supply with <30 mW No-load Input Power Percent of Full Load Efficiency (%) 115 VAC 230 VAC 25 82.4 79.2 50 82.7 81.8 75 82.6 82.0 100 82.5 82.4 Average 82.5 81.4 Requirements US EISA (2007) 74 ENERGY STAR 2.0 79 EuP (tier 2) 79 9.2 Energy Efficiency Requirements The external power supply requirements below all require meeting active mode efficiency and no-load input power limits. Minimum active mode efficiency is defined as the average efficiency of 25, 50, 75 and 100% of output current (based on the nameplate output current rating). For adapters that are single input voltage only then the measurement is made at the rated single nominal input voltage (115 VAC or 230 VAC), for universal input adapters the measurement is made at both nominal input voltages (115 VAC and 230 VAC). To meet the standard the measured average efficiency (or efficiencies for universal input supplies) must be greater than or equal to the efficiency specified by the standard. The test method can be found here: http://www.energystar.gov/ia/partners/prod_development/downloads/power_supplies/EP SupplyEffic_TestMethod_0804.pdf For the latest up to date information please visit the PI Green Room: http://www.powerint.com/greenroom/regulations.htm Page 19 of 34 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com DER-228 - 15 W, 12 V Supply with <30 mW No-load Input Power 23-Jul-09 9.2.1 USA Energy Independence and Security Act 2007 This legislation mandates all single output single output adapters, including those provided with products, manufactured on or after July 1st, 2008 must meet minimum active mode efficiency and no load input power limits. Active Mode Efficiency Standard Models Nameplate Output (PO) Minimum Efficiency in Active Mode of Operation <1W ≥ 1 W to ≤ 51 W > 51 W 0.5 × PO 0.09 × ln (PO) + 0.5 0.85 ln = natural logarithm No-load Energy Consumption Nameplate Output (PO) Maximum Power for No-load AC-DC EPS All ≤ 0.5 W This requirement supersedes the legislation from individual US States (for example CEC in California). 9.2.2 ENERGY STAR EPS Version 2.0 This specification takes effect on November 1st, 2008. Active Mode Efficiency Standard Models Nameplate Output (PO) Minimum Efficiency in Active Mode of Operation ≤1W > 1 W to ≤ 49 W > 49 W 0.48 × PO + 0.14 0.0626 × ln (PO) + 0.622 0.87 ln = natural logarithm Active Mode Efficiency Low Voltage Models (VO<6 V and IO ≥ 550 mA) Nameplate Output (PO) Minimum Efficiency in Active Mode of Operation ≤1W > 1 W to ≤ 49 W > 49 W 0.497 × PO + 0.067 0.075 × ln (PO) + 0.561 0.86 ln = natural logarithm No-load Energy Consumption (both models) Nameplate Output (PO) Maximum Power for No-load AC-DC EPS 0 to < 50 W ≥ 50 W to ≤ 250 W ≤ 0.3 W ≤ 0.5 W Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 20 of 34 23-Jul-09 9.3 DER-228 - 15 W, 12 V Supply with <30 mW No-load Input Power No-load Input Power 19 No Load Input Power (mW) 18 17 16 15 14 13 12 11 10 80 100 120 140 160 180 200 220 240 260 Input Voltage (VAC) Figure 7 – No-load Input Power vs. Input Line Voltage, Room Temperature, 60 Hz. Page 21 of 34 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com DER-228 - 15 W, 12 V Supply with <30 mW No-load Input Power Available Output Power vs Input Power (230 VAC) 100000 10000 Input Power (mW) 9.4 23-Jul-09 Po vs Pin 1000 100 10 1 0.1 0.1 1 10 100 1000 10000 100000 Output Power (mW) Figure 8 – Output Power vs Input Power at 230 VAC, Room Temperature, 60 Hz. Dashed line represents theoretical ideal (100% efficiency) Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 22 of 34 23-Jul-09 DER-228 - 15 W, 12 V Supply with <30 mW No-load Input Power 9.5 Available Standby Output Power The chart below shows the available output power versus line voltage at input power consumption levels of 1, 2 and 3 watts (respectively). Again, this performance illustrates the value of ON/OFF control, as it automatically maintains a high efficiency, even during very light loading. This simplifies complying with standby requirements that specify that a fair amount of power be available to the load at low input power consumption levels. The TinySwitch-III ON/OFF control scheme maximizes the amount of output power available to the load in standby operation when the allowable input power is fixed at a low value. This simplifies the design of products such as printers, set-top boxes, DVD players, etc. that must meet stringent standby power consumption requirements. Output Power (W) 3 Pin=3 W 2 Pin=2 W Pin=1 W 1 0 85 105 125 145 165 185 205 225 245 265 Input Voltage (VAC) Figure 9 – Available Output Power for 1, 2 and 3 Watts of Input Power. Page 23 of 34 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com DER-228 - 15 W, 12 V Supply with <30 mW No-load Input Power 9.6 23-Jul-09 Regulation 9.6.1 Load and Line 13 12.8 265 V 230 V 115 V Output Voltage (V) 12.6 12.4 85 V 12.2 12 11.8 11.6 11.4 11.2 11 0 0.125 0.25 0.375 0.5 0.625 0.75 0.875 1 1.125 1.25 Output Current (A) Figure 10 – Load and Line Regulation, Room Temperature. Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 24 of 34 23-Jul-09 DER-228 - 15 W, 12 V Supply with <30 mW No-load Input Power 10 Thermal Performance Temperature measurements of key components were taken using t-type thermocouples. The thermocouples were soldered directly to a Source pin of the TNY278PN device and to the cathode of the output rectifier. The thermocouples were glued to the external core and winding surfaces of transformer T1. The unit was sealed inside a large box to eliminate any air currents. The box was placed inside a thermal chamber. The ambient temperature within the large box was raised to 50 °C. The unit was then operated at full load and the temperature measurements were taken after they stabilized for 1 hour at 50 °C. Temperature (°C) Item 85 VAC 265 VAC Ambient inside the box 50 * 50* TNY278PNP (U1) 95 92 Transformer winding(T1) 83 88 Transformer core (T1) 74 81 Output Rectifier (D7) 99 101 *To simulate operation inside sealed enclosure at 40 °C external ambient. These results show that all key components have an acceptable rise in temperature. Figure 11 – Infrared Thermograph of Open Frame Operation, at Room Temperature. Cursor indicatesplastic temperature of U1 Page 25 of 34 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com DER-228 - 15 W, 12 V Supply with <30 mW No-load Input Power 23-Jul-09 11 Waveforms 11.1 Drain Voltage and Current, Normal Operation Figure 12 – 115 VAC, Full Load. Upper: IDRAIN, 0.4 A / div. Lower: VDRAIN, 50 V / div, 2 µs / div. Figure 13 – 230 VAC, Full Load. Upper: IDRAIN, 0.4 A / div. Lower: VDRAIN, 100 V / div. 2 µs / div Figure 14 – 115 VAC, Full Load. VDRAIN, 50 V, 20 µs / div. Figure 15 – 230 VAC, Full Load. VDRAIN, 100 V, 20 µs / div. Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 26 of 34 23-Jul-09 DER-228 - 15 W, 12 V Supply with <30 mW No-load Input Power 11.2 Output Voltage Start-Up Profile Start-up into full resistive load and no-load were both verified. A 12 Ω resistor was used for the load, to maintain 1 A under steady-state conditions. Figure 16 – Start-Up Profile, 115 VAC. Fast Trace is No-load Rise Time Slower Trace is Maximum Load 2 V, 5 ms / div. Figure 17 – Start-Up Profile, 230 VAC. Fast Trace is No-load Rise Time Slower Trace is Maximum Load 2 V, 5 ms / div. 11.3 Drain Voltage and Current Start-Up Profile Figure 18 – 85VAC Input and Maximum Load. Upper: VDRAIN, 100 V & 200 µs / div. Lower: IDRAIN, 0.4 A / div. Page 27 of 34 Figure 19 – 265 VAC Input and Maximum Load. Upper: VDRAIN, 200 V & 200 µs / div. Lower: IDRAIN, 0.4 A / div. Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com DER-228 - 15 W, 12 V Supply with <30 mW No-load Input Power 23-Jul-09 11.4 Load Transient Response (75% to 100% Load Step) Figure 20 – Transient Response, 115 VAC, 50-100-50% Load Step. Upper: VOUT 50 mV / div. Lower: IOUT 0.4 A, 0.5 ms / div. Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Figure 21 – Transient Response, 230 VAC, 50-100-50% Load Step. Upper: VOUT 50 mV / div. Lower: IOUT 0.4 A, 0.5 ms / div. Page 28 of 34 23-Jul-09 DER-228 - 15 W, 12 V Supply with <30 mW No-load Input Power 11.5 Output Ripple Measurements 11.5.1 Ripple Measurement Technique A modified oscilloscope test probe was used to take output ripple measurements, in order to reduce the pickup of spurious signals. Using the probe adapter pictured in Figure 22, the output ripple was measured with a 1 µF electrolytic, and a 0.1 µF ceramic capacitor connected as shown. Probe Ground Probe Tip Figure 22 – Oscilloscope Probe with Probe Master (www.probemaster.com) 4987A BNC Adapter. (Modified with wires for ripple measurement, and two parallel decoupling capacitors added) Page 29 of 34 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com DER-228 - 15 W, 12 V Supply with <30 mW No-load Input Power 23-Jul-09 11.5.2 Measurement Results The maximum voltage ripple at the output terminals of the power supply was measured as 58 mV. Figure 23 – Ripple, 85 VAC, Full Load. 20 µs, 50 mV / div. Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Figure 24 – Ripple, 115 VAC, Full Load. 20 µs, 50 mV / div. Page 30 of 34 23-Jul-09 DER-228 - 15 W, 12 V Supply with <30 mW No-load Input Power 12 Conducted EMI Conducted emissions tests were performed at 115 VAC and 230 VAC at full load (12 V, 1.25 A). Measurements were taken with both Artificial Hand connection to output return and output return floating. In both cases a resistor load was used connected at the end of an output cable. Composite EN55022B / CISPR22B conducted limits are shown. In all cases there was excellent (>10 dB) margin. 12.1 115 VAC, Full Load Line Neutral Artificial Hand Connected to Output Return Artificial Hand Connected to Output Return Output Floating Output Floating Figure 25– Conducted EMI at 115 VAC. Page 31 of 34 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com DER-228 - 15 W, 12 V Supply with <30 mW No-load Input Power 23-Jul-09 12.2 230 VAC, Full Load Line Neutral Artificial Hand Connected to Output Return Artificial Hand Connected to Output Return Output Floating Output Floating Figure 26 – Conducted EMI at 230 VAC. Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 32 of 34 23-Jul-09 DER-228 - 15 W, 12 V Supply with <30 mW No-load Input Power 13 Revision History Date 23-Jul-09 Page 33 of 34 Author PL Revision 1.0 Description & Changes Initial Release Reviewed Apps Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com DER-228 - 15 W, 12 V Supply with <30 mW No-load Input Power 23-Jul-09 For the latest updates, visit our website: www.powerint.com Power Integrations reserves the right to make changes to its products at any time to improve reliability or manufacturability. Power Integrations does not assume any liability arising from the use of any device or circuit described herein. POWER INTEGRATIONS MAKES NO WARRANTY HEREIN AND SPECIFICALLY DISCLAIMS ALL WARRANTIES INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT OF THIRD PARTY RIGHTS. PATENT INFORMATION The products and applications illustrated herein (including transformer construction and circuits external to the products) may be covered by one or more U.S. and foreign patents, or potentially by pending U.S. and foreign patent applications assigned to Power Integrations. A complete list of Power Integrations’ patents may be found at www.powerint.com. Power Integrations grants its customers a license under certain patent rights as set forth at http://www.powerint.com/ip.htm. 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