viper12A

AN2272 Application NoteVIPer12A-based Low Power AC/DC Adapter Introduction This application note describes a low power, (output power of 4.1W) general purpose adapter which is able to handle a wide range input voltages (88VAC to 265VAC). The adapter (Order Code STEVAL-ISA011V1) is based on the Viper12A monolithic device that has the power switch as well as the basic control function needed to implement a current mode flyback converter. February 2006 Rev. 1 1/33 www.st.com Table of Contents AN2272 - Application Note Table of Contents 1 STEVAL-ISA011V1 Board Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.1 Primary Side . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.1.1 1.1.2 Step 1, Input Capacitor Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Step 2, Transformer Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.2 Secondary Side . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 1.2.1 1.2.2 1.2.3 D11 Current and Power Dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Transformer Turns Ratio and D11 Peak Current . . . . . . . . . . . . . . . . . . . 10 C11 Output Capacitor Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 1.3 1.4 Completed Transformer Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Feedback Loop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 2 STEVAL-ISA011V1 Board Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2.1 Start-up Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2.1.1 2.1.2 Full Load Start-up Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 No Load Start-up Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 2.2 2.3 2.4 Temperature Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Dynamic Load Regulation Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Steady-State Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 2.4.1 2.4.2 Steady-State Full Load Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Steady-State No Load Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 2.5 EMI Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Appendix A STEVAL-ISA011V Demo Board Schematic . . . . . . . . . . . . . . . . . . . 30 Appendix B STEVAL-ISA011V1 Bill of Materials . . . . . . . . . . . . . . . . . . . . . . . . . 31 3 Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 2/33 Rev. 1 AN2272 - Application Note List of Figures List of Figures Figure 1. Figure 2. Figure 3. Figure 4. Figure 5. Figure 6. Figure 7. Figure 8. Figure 9. Figure 10. Figure 11. Figure 12. Figure 13. Figure 14. Figure 15. Figure 16. Figure 17. Figure 18. Figure 19. Figure 20. Figure 21. Figure 22. Figure 23. Figure 24. Figure 25. Full Load Start-up Waveforms at 88V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Full Load Start-up Waveforms at 265V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Full Load Start-up Waveforms at 115V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Full Load Start-up Waveforms at 230V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 No Load Start-up Waveforms at 88V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 No Load Start-up Waveforms at 265V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 No Load Start-up Waveforms at 115V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 No Load Start-up Waveforms at 230V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Step Load Change Stability Tests at 88V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Step Load Change Stability Tests at 265V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Step Load Change Stability Tests at 115V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Step Load Change Stability Tests at 230V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Steady-state Full Load 88VAC Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Steady-state Full Load 265V AC Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Steady-state Full Load 115V AC Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Steady-state Full Load 230V AC Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Steady-state No Load 88V AC Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Steady-state No Load 265V AC Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Steady-state No Load 115V AC Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Steady-state No Load 230V AC Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 115VAC Line Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 115VAC Line Neutral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 230VAC Line Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 230VAC Line Neutral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 STEVAL-ISA011V1 Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Rev. 1 3/33 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 4/33 Rev. . . . . . . . . . . . . . . . . . . Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Table 4. . . . . . . . . . . . . . . . . . . . . . . . 31 Document revision history . . . . . . . . . . Table 6. . . . . .List of Tables AN2272 . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Bill Of Materials. . . 20 Steady-state Full Load Condition Measurements . . . . . . . . . . . . . . . . . . . . 15 Component Critical Temperature Measurements . . . . . . Table 7. . . . . . . . . . . . . . . . . . . . . . . Table 2. . . . . . . . . . . . . Table 3. . 15 Start up Measures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Application Note List of Tables Table 1. . . . . . . . . . 1 . 23 Steady-state Output Voltage Ripple . . . . . . . . Table 5. . 1. ΔT = the time between the two conduction cycles of the input bridge diodes.1 Primary Side Step 1. As is shown in the Section 2. because it provides better dynamic performance. Maximum Load). Equation 1 is useful for this purpose: Equation 1 2 ⋅ P IN ⋅ ΔT C IN = ----------------------------------------------------------------2 2 V AC ( min )pk – V DC ( m in ) Where. Minimum Input Voltage.Application Note STEVAL-ISA011V1 Board Design 1 STEVAL-ISA011V1 Board Design In order to improve regulation. the PIN value used is calculated as PO/η. PIN = input power. and VDC(min) = selected minimum input voltage required for the flyback (converter) stage.1 1. VAC(min)pk = sinusoidal input waveform peaks (when AC voltage is at its minimum). the feedback loop is designed to have enough bandwidth so the converter can react on time to load changes. 1 5/33 . In this case. Input Capacitor Selection The first design step is to calculate the input capacitor value (C2a + C2b see STEVALISA011V Demo Board Schematic on page 30).3: Dynamic Load Regulation Tests on page 20.1. where PO is the maximum output power and η is the overall expected efficiency (70% in this example).e. The flyback converter is designed to work in Discontinuous Conduction Mode (DCM) in all operating conditions (i.AN2272 . Rev. CIN = input capacitor value. the board is able to handle high load step changes with very low variations in the output voltage. VDC(min) = selected minimum input voltage required for the flyback (converter) stage. 6/33 Rev. 1. For the board. two capacitors (C2a and C2b. The calculated value of C IN using Equation 1 is 16µF. and VR = reflected voltage (fixed to 90V).STEVAL-ISA011V1 Board Design An acceptable value for VDC(min) is 80% of VAC(min)pk: Equation 2 V DC ( min ) = 0. 1 . and fline = line frequency.Application Note 2V AC ( min ) V DC ( min ) 1 ΔT = ------------------------. DMAX = maximum duty cycle. This value is expressed as: Equation 4 ( V DC ( min ) ⋅ D M AX) LMAX = -------------------------------------------------------------.5mH 2 ⋅ P IN ⋅ f SW 2 Where. This value was selected because the tolerance for an electrolytic capacitor is usually around 20%. PIN = input power. ΔT = the time between the two conduction cycles of the input bridge diodes.⇒ LMAX = 3. This means that C IN = 20µF.2 Step 2. fSW = switching frequency (internally fixed in the VIper12A to 60kHz). see STEVAL-ISA011V Demo Board Schematic on page 30) of 10µF were used.1. The worst case is minimum input voltage and full load. LMAX = maximum inductance for discontinuous mode operation. Transformer Selection The next step is selecting a transformer with a Primary Inductance (LP) that allows the system to work at the boundary between Continuous Conduction Mode (CCM) and Discontinuous Conduction Mode (DCM).⋅ π – arc cos ⎛ -----------------------------⎞ ⎝ V AC ( m in )pk⎠ 2 ⋅ π ⋅ f line Where.8VAC ( min ) pk = ΔT is expressed as: Equation 3 AN2272 . IPRMS(max) = Primary Current root mean square. It is expressed as: Equation 8 D MAX I PRM S ( max ) = I PEAK ⋅ ------------------. PIN = input power. Rev. Using the transformer’s LP. which is the current that flows through the main switch and primary winding.Application Note STEVAL-ISA011V1 Board Design The DMAX at the boundary between CCM and DCM is expressed as: Equation 5 VR D MAX = --------------------------------------------.47 V DC ( m in ) + V R The transformer selected for this application provides an LP of 3mH. ● 2 ⋅ PIN -----------------------. the designer can calculate the: ● Peak Primary Current. which is a little less than the maximum inductance (LMAX) calculated in the first equation (3.5mH). 1 7/33 . Equation 7 2 ⋅ P IN ⋅ f SW ⋅ L P D M AX = ------------------------------------------------. IPEAK = peak primary current.⇒ D MAX = 0.42 f SW ⋅ L P and ● the primary side Root Mean Square (RMS) current value (IPRMS(max)).⇒ I PRMS ( max ) = 97mA 3 Where. and LP = primary inductance. expressed as. This ensures that the system is not working at boundary and will always function in DCM. Equation 6 I PEAK = Where. expressed as.⇒ D M AX = 0.AN2272 . fSW = switching frequency.⇒ I PEAK f SW ⋅ LP = 258mA actual Maximum Duty Cycle (DMAX). 1 .2 Secondary Side In order to select the output rectifier (secondary) diode D11 . or a safety margin of 20% to 30% if a standard “fast” diode is used.g.STEVAL-ISA011V1 Board Design AN2272 . the D 11 value is about 34V. If the calculated VR(max) is 23V and a Schottky diode is used (adding a 50% safety margin). VR(max) = maximum reverse voltage. 8/33 Rev. VOUT = output voltage. VR = reflected voltage. The safety margin prevents diode breakdown from oscillation caused by circuit parasitic elements (e. as well as the average and root mean square of the current flowing through it (see STEVAL-ISA011V1 Schematic on page 30). A commonly used selection method is to choose a diode with a 40% to 50% safety margin from the value given by the VR(max) calculation when a Schottky diode is used. transformer secondary inductance leakage or parasitic diode capacitance) when the MOSFET is turned ON. and VDC(max) = selected maximum input voltage.⋅ V DC ( m ax ) VR Where.Application Note The conduction losses in the main switch depend on the VIPer12A IPRMS(max) and ON resistance. This makes the STPS340U (with 40V breakdown voltage) an excellent choice for this application. the designer needs to know the maximum reverse voltage that the diode has to sustain. 2 1. VR(max) is calculated as follows: Equation 10 V O UT V R ( max ) = V OUT + -----------------. PVIPer12A = VIPer12A conduction losses. and are expressed as: Equation 9 P VIPer12A = r ds ( on ) ⋅ I PRMS ( m ax ) Where. and rds(on) = VIPer12A ON resistance. 1 9/33 .Application Note STEVAL-ISA011V1 Board Design 1. 2 Rev.2. IPKS (peak current at the secondary winding) can be calculated as the primary peak current multiplied by the turns ratio. PlossD = diode power dissipation. Note: The formula and the correct values for VdD and r dD are in the diode datasheets. IDRMS = current root mean square.1 D11 Current and Power Dissipation ● The average current flowing through D11 is the output current while the IDRMS value is expressed as: Equation 11 D s – cond I DRMS = I PKS ⋅ -------------------3 Where. ● D11 power dissipation is calculated as follows: Equation 12 P los sD = V dD ⋅ I D ( avg ) + r dD ⋅ I DRMS Where. and rdD = dynamic resistance. IPKS = peak current at secondary winding.AN2272 . ID(avg) = diode average current. VdD = drop voltage (when the diode is forward-biased). Note: This formula applies only to DCM operation. For one output flyback. and Ds_cond = conduction duty cycle of the secondary diode. ⋅ I PKP NS Where. and IPKP = peak power current Note: The worst case (maximum power dissipation) will be in full load condition. NP = Primary Turns.2 Transformer Turns Ratio and D11 Peak Current ● The turns ratio that is selected for the transformer depends on the output voltage.2. IPKS is then expressed as: Equation 15 NP I PKS = -----. 10/33 Rev. Ds_cond = Secondary Diode conduction duty cycle. NS = Secondary Turns. IPKS = peak current at secondary winding. VDROP(avg) is expressed as: Equation 13 V DROP ( avg ) = V dD + r dD ⋅ IO Where.Application Note 1. and VO = output voltage. VR = reflected voltage. 1 . ● The D11 conduction duty cycle is expressed as: Equation 16 I PKP ⋅ LP ⋅ f SW D s – co nd = -------------------------------------------VR Where. IO = diode output current. and fSW = switching frequency. ● Using the calculated turns ratio. rdD = dynamic resistance. Keeping in mind the voltage drop across its dynamic resistance. the chosen reflected voltage. VDROP(avg) = average voltage drop (across the output diode) VdD = drop voltage (when the diode is forward-biased).STEVAL-ISA011V1 Board Design AN2272 . LP = primary inductance. and the average voltage drop across the output diode.= --------------------------------------------NS V O + V DRO P ( avg ) Where. the turns ratio is expressed as: Equation 14 VR NP ------. and ● Using the calculated VDROP(avg) value. Rev.Application Note STEVAL-ISA011V1 Board Design 1. and IO = output current. ΔVO = output voltage ripple. and IPKS = peak current at secondary winding. The output voltage ripple is mainly due to the Equivalent Series Resistor (ESR). which is expressed as: Equation 18 ICAPRMS = I 2 DRMS –I 2 O Where. see STEVAL-ISA011V1 Schematic on page 30) depends on the output voltage ripple specification (ΔVO = 300mV). The C11 capacitor current rate has to be higher than the calculated current.AN2272 . The MBZ Type 1500 μF 10V by RUBYCON capacitor was selected for this application.2. The AC component of the current flowing through the output diode is also that of the current flowing through the capacitor. 1 11/33 . ESR MAX = maximum allowed ESR rating. so we have to select a capacitor with an ESR lower than the maximum allowed ESR value: Equation 17 ΔV O ESR MAX = -------------I PKS Where. and the ripple current rate of the capacitor itself. IDRMS = diode current root mean square.3 C11 Output Capacitor Selection The output capacitor selection (C 11. ICAPRMS = capacitor current root mean square. the current limit of the VIPer12A (ILIM = 480mA. the peak current (calculated in Equation 6: on page 7) must be used. ΔIFB = VIPer12A feedback pin current. and Peak).Application Note 1. ΔVO = output voltage ripple. 1 . zfly = flyback zero compensation reference. Average. For thermal limits (power dissipated in the magnetic core). 2. then for winding size selection. 1. pfly = flyback pole reference. and Winding Current Values (RMS. The transformer (reference number SRW16ES_E44H013) was designed and manufactured by TDK using aforementioned the data. 3. In order to prevent transformer saturation during the start-up phase. Turns Ratio. They include: ● ● ● Primary Inductance. The RMS value of the current flowing through the windings is used first for calculating the power dissipated in the windings. and 12/33 Rev.4 Feedback Loop The transfer function 'control-to-output' for a flyback converter operating in DCM is given by the following formula: Equation 19 s ⎛ 1 + --------⎞ ⎝ z fly⎠ ΔV O ( s ) ⁄ ΔI FB ( s ) = G fly ⋅ ----------------------s ⎛ 1 + --------⎞ ⎝ p ⎠ fly Where. Gfly = flyback gain. Notes: 1.STEVAL-ISA011V1 Board Design AN2272 . see datasheet for details) must be considered as the peak current.3 Completed Transformer Design All of the calculations for the transformer design are complete. The last pole of the compensation network is used to compensate flyback zero due to the ESR.⋅ G ID I PK Where. one zero compensation network) is expressed as: Equation 22 1 z fly = ------------------------------------------C OUT ⋅ ESR OUT Where. zfly = flyback zero. Equation 20 VO Gfly = ---------.Application Note STEVAL-ISA011V1 Board Design Using the VIPer12A input current (IFB) to the feedback pin and Gfly values. 1 13/33 . VO = voltage output. and ESROUT = equivalent series resistor output. Gfly = flyback gain. and GID = feedback current-to-drain current gain (see VIPer12A datasheet for details). typically. Compensation zero was used in order to compensate the pfly and. pfly = flyback pole reference. IPK = primary peak current. ● The flyback pole value is expressed as: Equation 21 2 p fly = ---------------------------------------------------------------------------------C OUT ⋅ ( R L + 2 ⋅ ESR O UT ) Where.AN2272 . RL = inductor resistance. Rev. COUT = output capacitor (see C11. STEVAL-ISA011V1 Schematic on page 30). ● The flyback zero value (for two poles. One pole is located at zero frequency in order to maximize the precision of the regulation. it has to be located between one-half and double the pfly frequency. ⋅ ---------------------------------------------------------R 6 ⋅ R 8 ⋅ C 8 s ⋅ ( 1 + s ⋅ R FB ⋅ C 5 ) Δ VO ( s ) Where. CTR = optocoupler Current Transfer Ratio RFB = VIPer12A feedback pin input impedance.5kHz to provide the converter with good bandwidth.Application Note Loop Gain crossover frequency is the last calculation required to define the compensation network. the crossover frequency selected is as high as 2. In this design. 14/33 Rev. Note: Using these resistance and capacitance values as guidelines will provide the user with a stable loop as well as the required converter bandwidth.STEVAL-ISA011V1 Board Design ● AN2272 . ΔVO = output voltage ripple. The Transfer Function output control is expressed as: Equation 23 ( 1 + s ⋅ R9 ⋅ C 8 ) Δ IFB ( s ) CTR -----------------------.= ----------------------------------. 1 . ΔIFB = VIPer12A feedback pin current. 458 0.470 0. 1 15/33 .505 0. safe operating area of the devices. Table 1.515 No load 0. Symbol VAC(max) VAC(min) VO ΔVO IO η230 η115 Electrical Characteristics Description Maximum AC Input Voltage Minimum AC Input Voltage Output Voltage Maximum Output Voltage Ripple Maximum Output Current Efficiency (at full Load and 230VAC) Efficiency (at full Load and 115VAC) Limits or Value 265VRMS 88V RMS 4.Application Note STEVAL-ISA011V1 Board Tests 2 STEVAL-ISA011V1 Board Tests The tests performed with the STEVAL-ISA011V1 demo board are used to evaluate the converter behavior in terms of: ● ● ● ● efficiency. and load regulation.472 0. For flyback converters. and its maximum output power is 4. All the measured values are within the rated maximum values of the VIPer12A so they are not critical for device operation. maximum.507 0. Start up Measures VDRAIN(max) (V) IDRAIN(max) (mA) Full load 0.515 VINAC (VRMS) Full load 88 115 230 265 352 393 581 638 No load 353 401 581 633 Rev.5 300 900 70 70 Units V V V mV mV % % Table 2.460 0. and for minimum.1W with one output of 4.AN2272 . the most critical conditions for the main switch in terms of Maximum Drain Current and of Maximum Drain Voltage (when no abnormal event occurs). are those that exist during the start-up phase. 2. line regulation. The maximum values for drain voltage and current are measured in both full load and no load conditions (the two extreme points in terms of load).1 Start-up Tests The diagnostic board will handle a wide range of AC input voltage (88VAC to 265VAC).5V. and nominal input voltages (see Table ). Its maximum output current is 900mA (see Table 1). Green (Ch4) = output voltage. Figure 3. and Yellow (Ch1) = drain voltage.1 Full Load Start-up Waveforms Figure 1. Figure 2. and Yellow (Ch1) = drain voltage.STEVAL-ISA011V1 Board Tests AN2272 . Green (Ch4) = output voltage. for the minimum (88VAC). Figure 1. Figure 2. Magenta/Red (Ch3) = auxiliary output voltage for the VIPer12A self-supply (on VDD pin).1. maximum (265VAC). 1 . and nominal voltages (115VAC and 230VAC). Full Load Start-up Waveforms at 88V Notes: Cyan/Blue (Ch2) = drain current. 16/33 Rev. and Figure 4 on page 17 show the most pertinent waveforms that occur during the circuit start-up phase when it is in Full Load condition. Magenta/Red (Ch3) = auxiliary output voltage for the VIPer12A self-supply (on VDD pin).Application Note 2. Full Load Start-up Waveforms at 265V Notes: Cyan/Blue (Ch2) = drain current. Full Load Start-up Waveforms at 115V STEVAL-ISA011V1 Board Tests Notes: Cyan/Blue (Ch2) = drain current.AN2272 . and Yellow (Ch1) = drain voltage. Green (Ch4) = output voltage. Rev. Magenta/Red (Ch3) = auxiliary output voltage for the VIPer12A self-supply (on VDD pin). Figure 4.Application Note Figure 3. Full Load Start-up Waveforms at 230V Notes: Cyan/Blue (Ch2) = drain current. Green (Ch4) = output voltage. 1 17/33 . Magenta/Red (Ch3) = auxiliary output voltage for the VIPer12A self-supply (on VDD pin). and Yellow (Ch1) = drain voltage. 18/33 Rev. Green (Ch4) = output voltage.1.2 No Load Start-up Waveforms Figure 5. No Load Start-up Waveforms at 88V Notes: Cyan/Blue (Ch2) = drain current.STEVAL-ISA011V1 Board Tests AN2272 . and Yellow (Ch1) = drain voltage. Figure 6. Figure 7. Magenta/Red (Ch3) = auxiliary output voltage for the VIPer12A self-supply (on VDD pin). Figure 6.1. for the minimum (88VAC). and nominal voltages (115VAC and 230VAC). No Load Start-up Waveforms at 265V Notes: Cyan/Blue (Ch2) = drain current.Application Note 2. Green (Ch4) = output voltage. Figure 5. and Figure 8 on page 19 show the same waveforms (Section 2. Magenta/Red (Ch3) = auxiliary output voltage for the VIPer12A self-supply (on VDD pin). 1 . maximum (265VAC).1) as they occur during the circuit start-up phase when no load is applied. and Yellow (Ch1) = drain voltage. AN2272 . Figure 8. and Yellow (Ch1) = drain voltage. No Load Start-up Waveforms at 115V STEVAL-ISA011V1 Board Tests Notes: Cyan/Blue (Ch2) = drain current. No Load Start-up Waveforms at 230V Notes: Cyan/Blue (Ch2) = drain current. Green (Ch4) = output voltage. Green (Ch4) = output voltage. and Yellow (Ch1) = drain voltage. 1 19/33 .Application Note Figure 7. Magenta/Red (Ch3) = auxiliary output voltage for the VIPer12A self-supply (on VDD pin). Rev. Magenta/Red (Ch3) = auxiliary output voltage for the VIPer12A self-supply (on VDD pin). with 3ms periods and a duty cycle of 50%.STEVAL-ISA011V1 Board Tests AN2272 . maximum (265VAC). and nominal voltages (115VAC and 230VAC). in Full Load conditions. but is related to the VIPer12A Burst mode operation. Note: Even with the oscillation. Note: The tests were performed at 25°C (ambient temperature). 1 . in terms of speed and overshoot. with some mV overshoots. ● The output voltage (Ch3) has a variation of some tenths of a mV (about 40mV). The VIPer12A feedback pin voltage (Ch1) in Figure 10 on page 21 shows that when the input voltage is 265VAC. the load is 180mV (its minimum value) while the output and feedback pin voltages show some oscillation. Component Critical Temperature Measurements VIPer12A 38 39 42 45 Transformer 37 36 38 35 Clamp Resistor 36 37 38 39 Output Diode 45 45 45 45 Units °C °C °C °C VINAC (VRMS) 88V 115V 230V 265V 2. in terms of power dissipation) for the board’s main components. These results indicate very good dynamic behavior on the part of the system. for the minimum (88VAC). Figure 9. Table 3. and Figure 12 on page 22 show the waveforms as they occur during the circuit load changes. and Figure 10 on page 21. Table 3 shows critical temperatures (the most stress measured.2 Temperature Tests These tests verify the board’s device and component temperatures. load changes from a minimum of 180mA to a maximum of 900mA are applied to the circuit as squarewaves. This oscillation is not related to a low phase margin of the Loop Gain. During these tests. the output voltages are still regulated well.Application Note 2. and Figure 11.3 Dynamic Load Regulation Tests These tests monitor and verify the stability and quality of the system response to load changes. ● 20/33 Rev. Rev. and Cyan/Blue (Ch2) = output (load) current. Step Load Change Stability Tests at 265V Notes: Magenta/Red (Ch3) = output voltage. 1 21/33 .Application Note Figure 9. Figure 10.AN2272 . and Cyan/Blue (Ch2) = output current. Yellow (Ch1) = feedback pin voltage. Step Load Change Stability Tests at 88V STEVAL-ISA011V1 Board Tests Notes: Magenta/Red (Ch3) = output voltage (set to 50mV/division). Yellow (Ch1) = VIPer12A feedback pin voltage. Yellow (Ch1) = feedback pin voltage. Figure 12. 1 .STEVAL-ISA011V1 Board Tests Figure 11.Application Note Notes: Magenta/Red (Ch3) = output voltage. Step Load Change Stability Tests at 230V Notes: Magenta/Red (Ch3) = output voltage. and Cyan/Blue (Ch2) = output current. Yellow (Ch1) = feedback pin voltage. and Cyan/Blue (Ch2) = output current. 22/33 Rev. Step Load Change Stability Tests at 115V AN2272 . 13 4.13 VO (V) 4. Steady-state Full Load Condition Measurements PIN (W) 5. Table 4. Note: The tests were performed in Full Load conditions. 1 23/33 .9 5.59 VINAC (VRMS) 88V 115V 230V 265V η (%) 70 70 70 68 Table 5.9 6. maximum (265VAC).59 4.13 4. and nominal input voltages (115VAC and 230VAC). and voltage ripple which is superimposed on the output voltage at the switching frequency (see Table 5).59 4.AN2272 .13 4.4 Steady-State Tests These tests evaluate the converter’s behavior (see Table 4).9 5. The measurements include: ● ● ● converter efficiency for the minimum (88VAC).Application Note STEVAL-ISA011V1 Board Tests 2.59 4. where voltage output is measured in both full load and no load conditions). Steady-state Output Voltage Ripple Input Voltage (V RMS) 88V 115V 230V 265V ΔVO at Full Load 210mV 214mV 215mV 220mV Rev.1 POUT (W) 4. output voltage quality (Static Load regulation. for the minimum (88VAC). Figure 13. 24/33 Rev. and Figure 15 and Figure 16 on page 25 show the waveforms that occur during converter steady-state testing when it is in Full Load condition. and Cyan/Blue (Ch2) = drain current. Steady-state Full Load 88VAC Waveforms Notes: Magenta/Red (Ch3) = output voltage. Green (Ch4) = drain voltage. Green (Ch4) = drain voltage.STEVAL-ISA011V1 Board Tests AN2272 . Steady-state Full Load 265VAC Waveforms Notes: Magenta/Red (Ch3) = output voltage. 1 . and Cyan/Blue (Ch2) = drain current. Figure 14.1 Steady-State Full Load Waveforms Figure 13 and Figure 14. maximum (265VAC).Application Note 2. and nominal voltages (115VAC and 230VAC).4. and Cyan/Blue (Ch2) = drain current. Green (Ch4) = drain voltage. Steady-state Full Load 115VAC Waveforms STEVAL-ISA011V1 Board Tests Notes: Magenta/Red (Ch3) = output voltage. Rev. and Cyan/Blue (Ch2) = drain current. Steady-state Full Load 230VAC Waveforms Notes: Magenta/Red (Ch3) = output voltage. Figure 16. 1 25/33 .Application Note Figure 15.AN2272 . Green (Ch4) = drain voltage. 1 . 26/33 Rev. for the minimum (88VAC). maximum (265VAC).Application Note 2.4.2 Steady-State No Load Waveforms Figure 17 and Figure 18. Figure 17. Steady-state No Load 88VAC Waveforms Notes: Magenta/Red (Ch3) = output voltage. and Figure 19 and Figure 20 on page 27 show the waveforms that occur during converter steady-state testing when it is in No Load condition.STEVAL-ISA011V1 Board Tests AN2272 . and Cyan/Blue (Ch2) = drain current. Green (Ch4) = drain voltage. and Cyan/Blue (Ch2) = drain current. Steady-state No Load 265VAC Waveforms Notes: Magenta/Red (Ch3) = output voltage. and nominal voltages (115VAC and 230VAC). Green (Ch4) = drain voltage. Figure 18. 1 27/33 . Green (Ch4) = drain voltage. Figure 20.Application Note Figure 19. Green (Ch4) = drain voltage. and Cyan/Blue (Ch2) = drain current.AN2272 . Rev. Steady-state No Load 115VAC Waveforms STEVAL-ISA011V1 Board Tests Notes: Magenta/Red (Ch3) = output voltage. Steady-state No Load 230VAC Waveforms Notes: Magenta/Red (Ch3) = output voltage. and Cyan/Blue (Ch2) = drain current. Figure 21 and Figure 22.Application Note 2. and Figure 23 and Figure 24 on page 29 illustrate that the conducted EMI induced by the converter to the main are below the normative limits. 1 . 115VAC Line Voltage Figure 22.5 EMI Tests Pre-compliant tests with European Normative EN55022 for electromagnetic interference (EMI) were performed.STEVAL-ISA011V1 Board Tests AN2272 . Figure 21. 115VAC Line Neutral 28/33 Rev. Note: Figure 21 through Figure 24 show the Input current spectrum to be inside the 150kHz to 30MHz frequency range. 230VAC Line Neutral Rev.AN2272 .Application Note Figure 23. 1 29/33 . 230VAC Line Voltage STEVAL-ISA011V1 Board Tests Figure 24. 5V .5k 150pF 400V R1 12k 1/4W T1 J2 1 2 R8 10k R6 560 R5 1k 1% Precision Resistor Appendix A 1A 600V Bridge STEVAL-ISA011V Demo Board Schematic D4 2– U5 PC817 R9 56k F1 315mA 10k R2 C8 100nF J3 C7 2. STEVAL-ISA011V1 Schematic S1 S2 FB VDD D1 1 2 3 4 C4 10µF 4 3 1 2 C5 33nF 1 STEVAL-ISA011V Demo Board Schematic CON2 33 NTC1 C1 2 Rev.9A + 4 C2a 10µF 400V C2b 10µF 400V + R3 1. 1 4 R4 10E Viper12A U2 D2 30/33 1 L12 1.5k 1% Precision Resistor 1 2 0.Application Note AI12225 .1 3 8 7 6 5 D4 D3 Figure 25.2nF Y1 U3 TL431 3 R7 12.0.25 C3 2 D11 STPS340U 8 + 7 1.1µF CX2 cap AN2272 .5mH 0.5mF 10V MBZ Rubycon 3 D3 1N4148 D5 STTH1R06 C11 4. 5mH 0. Item 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 STEVAL-ISA011V1 Bill of Materials Bill Of Materials Qty 1 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 1 1 1 1 1 1 1 1 1 1 1 Reference C1 C2a.5k 10E 1k 560 12.Application Note STEVAL-ISA011V1 Bill of Materials Appendix B Table 6.8nF Y1 100nF Value 1.25A 33Ω 12K 1/4W 10k 1.AN2272 . 1 31/33 .5mF 10V MBZ (10X16) Rubycon (Low ESR Capacitor) 1N4148 1A 600V Bridge STTH1R06 STMicroelectronics Part STPS340U (SMB Package) STMicroelectronics Part 250mA 1.5k 1% Precision Resistor 10k 1% Precision Resistor 56k TDK SRW16ES_E44H013 VIPer12A (ST Part) TL1431 (ST Part) PC817 Rev.1uF CX2 cap 10uF 400V 150pF 400V 10uF 33nF 47pF 400V 1. C2b C3 C4 C5 C6 C7 C8 C11 D3 D4 D5 D11 F1 L12 NTC1 R1 R2 R3 R4 R5 R6 R7 R8 R9 T1 U2 U3 U4 0. 1 .Revision History AN2272 . Document revision history Date 2-February-2006 Revision 1 First edition Changes 32/33 Rev.Application Note 3 Revision History Table 7. Germany . 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