EPR-000008

Engineering Prototype Report (EPR-000008) Title 1.2 W, Universal Input, Non-isolated, TNY254 (EP8) Customer Author Document Number Date Revision Abstract Home Appliance Market S.L. EPR-000008 08-May-2001 10 This document presents the specification, schematic & BOM, inductor calculation, test data and wave forms for a low cost, non-isolated, converter for a home appliance application (triac driving). Power Integrations, Inc. 5245 Hellyer Avenue, San Jose, CA 95138 USA. Tel: +1 408-414-9200 Fax: +1 408-414-9201 www.powerint.com EPR-000008 – 1.2 W Universal Input Non-Isolated TNY254 23-April-2001 Table Of Contents 1 2 3 Introduction...................................................................................................................... 3 Power Supply Specification ............................................................................................. 3 Schematic........................................................................................................................ 4 3.1 Configuration “1” – 2 kV (1.2/50 ms) Surge Withstand ................................................. 4 3.2 Configuration “2” – 6 kV (1.2/50 ms) Surge Withstand ................................................. 5 4 Circuit Description ...........................................................................................................6 5 Layout ............................................................................................................................. 7 6 Bill of Materials ................................................................................................................ 8 6.1 Configuration ”1”, 2 kV ................................................................................................. 8 6.2 Configuration ”2”, 6 kV ................................................................................................. 8 7 Inductor ........................................................................................................................... 9 7.1 Calculation ................................................................................................................... 9 7.2 Spreadsheet .............................................................................................................. 10 8.0 Performance Data ......................................................................................................... 11 8.1 Efficiency ................................................................................................................... 11 8.2 Regulation..................................................................................................................12 8.3 Temperature .............................................................................................................. 12 8.4 Waveforms................................................................................................................. 13 8.5 Transient Response................................................................................................... 16 8.6 Surge Voltage Immunity (2 kV and 6 kV, 1.2/50 ms per IEC1000-4-5)....................... 17 Revision History.................................................................................................................... 19 Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 2 of 20 23-April-2001 EPR-000008 – 1.2 W Universal Input Non-Isolated TNY254 1 Introduction There are three specific requirements for this power supply: 1. To provide power for driving a trial requires that the output power be referenced to the input line (L), with no series impedance, therefore only ½ wave rectification is allowed and the switch must be in the return side of the primary switching circuit. EMI filtering, if necessary, has to be implemented at the system level. 2. The unit has to operate at 85 °C ambient. 3. The unit has to withstand 2 kV (configuration “1”, page 4) and 6 kV (configuration ”2”, page 5) input surge voltage as defined by IEC 1000-4-5 (1.2/50 ms). The surge protection added to satisfy these requirements reduces the converter efficiency. It would be more beneficial (lower cost, improved efficiency) if the surge protection were implemented at the system (appliance) level. 2 Power Supply Specification Symbol VAC fLINE VOUT VRIPPLE IOUT Min 85 47 10.8 0 12 80 Typ Max 265 63 13.2 120 100 Units VAC Hz V MV MA Comment 50/60 Hz The specification below is for the worst case (6 kV configuration ”2”) Description Input Input Voltage Input frequency Output Output Voltage Output Ripple Voltage Output Current Load Regulation Line Regulation Power Output Continuous Output power Power supply efficiency Environmental Temperature EMI – conducted Safety Input Surge Voltage Input Surge Voltage 12 V+/-10%* of VOUT @ full load ~200 mA short 0-100% load 85-265 VAC, full load 0-85 °C internal ambient** @low line, full load 6” x 6” x 4” enclosure Designed to meet CISPRR 22B (FCCB) Designed to meet IEC950 IEC1000-4-5 IEC1000-4-5 POUT h TAMB 0 50 0 1.2 W % 85 C Config. ”1” Config. ”2” 2 6 kV kV * +/-5% with 2% Zener. **The unit was placed in a 6” x 6” x 4” enclosure inside the temperature chamber. Page 3 of 20 Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com EPR-000008 – 1.2 W Universal Input Non-Isolated TNY254 23-April-2001 3 Schematic 3.1 Configuration “1” – 2 kV (1.2/50 ms) Surge Withstand Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 4 of 20 23-April-2001 EPR-000008 – 1.2 W Universal Input Non-Isolated TNY254 3.2 Configuration “2” – 6 kV (1.2/50 ms) Surge Withstand Page 5 of 20 Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com EPR-000008 – 1.2 W Universal Input Non-Isolated TNY254 23-April-2001 4 Circuit Description The circuit is a fail-safe, non-isolated fly-back topology. Fail-safe means that the output is not subjected to high voltage DC if the switch (U1) fails, since the diode D2 blocks the voltage. During the ON time (U1 conducting), L1 is charged up to ILIMIT of the TNY254 (0.25 A type.), from the energy stored in C1. During the OFF time (U1 blocking), the energy stored in L1 is transferred to C3 and the load via D2. The device switching frequency is 44 kHz. The surge protection circuit has to prevent the TinySwitch VDSMAX from exceeding 700 V. The surge protection for configuration ”1” (2 kV) and configuration ”2” (6 kV) is illustrated in the schematics (pages 4, 5). Configuration ”1” relies on the current/energy-limiting resistor R2 to keep the maximum charging voltage of C1 during a +2 kV surge below 700 V. For the -2 kV surge the diodes D1+D3 block the voltage. Configuration ”2” relies on the current/energy-limiting resistor R1 to limit the current in the MOV (RV1) to approximately 50 A peak, such that the RV1 clamping voltage is kept well under 1 kV (~700 V). During the +6 kV surge, R2 limits C1 charging current so that the maximum voltage does not exceed 700 V. During the -6 kV surge, D1 blocks the RV1 clamping voltage from reaching C1. In both configurations, the fusible resistor R2 provides protection for component failure. Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 6 of 20 23-April-2001 EPR-000008 – 1.2 W Universal Input Non-Isolated TNY254 5 Layout CAUTION! This is a non-isolated power supply with the low voltage return referenced to the input line (85-265 VAC). Do not touch the unit while it is powered. Power the board using a safety isolation transformer so the high voltage probe return is not referenced to the neutral of the input line. For the drain-to-source voltage waveforms connect the high voltage probe tip to jumper JP1 and the probe ground to test point TP1. For switching current waveforms replace jumper JP1 with a wire loop and use a Tektronix A6302 current probe and AM503 current probe amplifier (with TM501 power module) or equivalent. PCB cut out for 6 kV only TP1 JP1 Page 7 of 20 Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com EPR-000008 – 1.2 W Universal Input Non-Isolated TNY254 23-April-2001 6 Bill of Materials 6.1 Item 1 2 3 4 5 6 7 8 9 10 11 12 13 14 *Optional **Remove middle pin Configuration ”1”, 2 kV Qty. 1 1 1 2 1 1 1 1 1 1 1 1 1 1 Ref. C1 C2 C3 D1, D3 D2 **J1 J2 *LED1 L1 R2 *R3 U1 U2 VR1 Description 6.8 mF, 400 V, 105 C 0.1 mF, 50 V, ceramic 220 mF 25 V (0.12 W) Glass Passivated Diode 600 V, 1 A, 75 ns Header, 3 pos., 0.156 spacing Header, 2 pos., 0.156 spacing low current 1.5 mH, 0.4 ADC, 0.2 AAC, 600 VDC, 180 W, flame proof, fusible, 3 W; 8.2 kW, ¼ W Off-line Switcher Optocoupler Zener, 12 V ±5% Manufacturer Rubycon Panasonic Panasonic Vishay/Lite On General Instrument Molex Molex Siemens/HP Chilisin Vitrohm (Farnell Components.) Power Integrations Siemens/NEC Diodes Incorporated (08WX7849) 1N4007GP UF4005 26-48-1035 26-48-1025 LG3369/HLMP1790 Part Number 400BXA6R8M10x16 ECU-S1H104KBB TNY254P SFH615-2/PS2501-1 1N5242B 6.2 Item 15 16 Configuration ”2”, 6 kV Qty. 1 1 Ref. RV1 R1 Description Varistor, 275 VAC, 14 mm 100 W, 15 J, 500 VAC Manufacturer Harris/Littlefuse Ohmite Part Number V275LA20A OX 101 (Add the following items to Configuration "1" and subtract D3) Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 8 of 20 23-April-2001 EPR-000008 – 1.2 W Universal Input Non-Isolated TNY254 7 Inductor 7.1 Calculation The inductor value can be determined using the TNY253-255 flyback transformer spreadsheet with the following considerations: 1) the frequency value (fL) is ½ the line frequency, 25 Hz for 50 Hz, 30 Hz for 60 Hz, to account for half wave rectification. 2) Z factor, the ratio between the secondary losses and the total losses, has to reflect the dominance of the primary losses, as the TinySwitch losses (high Rdson) overshadow the output diode losses. Z factor does not reflect the extra power loss due to R1 and R2. The efficiency used in the spreadsheet is only the efficiency of the converter portion of the supply, it does not include the losses in the input resistor. 3) the output diode rating can be calculated from the formula (VR ³ PIVS/0.8), where PIVS=VMAX+VO-VDS. The inductor can be looked at as a transformer with 1:1 turns ratio, therefore VOR=VO+VD. 4) the output capacitor minimum value is dictated by the output RMS ripple current and the maximum value by the specified maximum output voltage ripple. Select the next higher standard “L” value (for the rated “I”) from a qualified vendor (min. 400 VDC voltage rated inductor) like Chilisin, and the smallest DC resistance. Page 9 of 20 Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com EPR-000008 – 1.2 W Universal Input Non-Isolated TNY254 23-April-2001 7.2 Spreadsheet OUTPUT UNIT ACDC_TNY_REV1_8_072699.xls: TinySwitch Continuous/Discontinuous Flyback Transformer Design Spreadsheet Customer Minimum AC Input Voltage Maximum AC Input Voltage AC Mains Frequency Output Voltage Output Power Efficiency Estimate Loss Allocation Factor Bridge Rectifier Conduction Time Estimate Input Filter Capacitor Continuous Mode Operation or Discontinuous Mode Operation? Continuous 115/230 VAC 5W A A Hz V Minimum Current Limit Maximum Current Limit Minimum Frequency Voltage Drop Between Drain to Source ACDC_TNY_Rev1.8_072699 INPUT Copyright Power Integrations, Inc. 1999 ENTER APPLICATION VARIABLES VACMIN 77 VACMAX 265 25 fL VO 12 PO 1.2 n 0.65 0.1 Z tC 3 CIN 6.8 MODE OF OPERATION Continuous ('c') or c Discontinuous ('d')? V V Hz V W mS mF n ENTER TinySwitch Parameters Universal TinySwitch TNY254 4W ILIMITMIN 0.23 ILIMITMAX 0.28 fSmin 40000 VDS 10 ENTER Output Diode Parameters Output Diode 500 VR ID 1 VD 1 k 0.8 Design Parameters VMIN VMAX IP DMAX KRP VOR VDRAIN PIVS LP CURRENT WAVEFORM SHAPE PARAMETERS IAVGmax IAVGmin IRMS IR ISP ISRMS IO IRIPPLE IOS V A V Diode Maximum Peak Repetitive Reverse Voltage Diode Average Forward Current Diode Forward Voltage Drop Diode Peak to RMS Current Factor (k=0.9 for Schottky, k=0.8 for PN Diode) Minimum DC Input Voltage Maximum DC Input Voltage Peak Primary Current Duty Cycle at Minimum DC Input Voltage Ripple to Peak Current Ratio (0.6