AN3105 Application note 48 V - 130 W high efficiency converter with PFC for LED street lighting applications - European version By Claudio Spini Introduction Nowadays, LEDs are becoming ever more popular, thanks to their particular characteristics, such as high efficiency and long life, and therefore they are pushing the innovation of current lamp types and strongly contributing to reducing the energy consumption for internal or external lighting. This is also the case in street lighting applications, where higher efficiency and long life are vital for reducing costs. For these reasons a street lighting power supply designed to power an LED lamp must have high efficiency and at least a similar lifetime, in order to guarantee the maintenance free operation required by these kinds of applications. This application note describes the characteristics and features of a 130 W demonstration board (EVL130W-SL-EU), tailored on an LED power supply specification for street lighting. The circuit is composed of two stages; a front-end PFC using the L6562AT and an LLC resonant converter based on the L6599AT. The peculiarities of this design are; very high efficiency, extended European input mains range (177-277 VAC) operation, and long term reliability. Because reliability (MTBF - “Mean Time Between Failures”) in power supplies is typically affected by electrolytic capacitors and their typical high failure rate, unless using very expensive types, this board offers a very innovative design approach as the board doesn't implement any electrolytic capacitors, which are replaced by film capacitors from EPCOS. Component de-rating has also been carefully applied during the design phase, decreasing the component stress as recommended by MIL-HDBK-217D. The number of components, thanks to the use of the new L6562AT and L6599AT devices, has also been minimized, therefore increasing the MTBF and optimizing the total component cost. Thanks to the high efficiency achieved no heatsinks are required. The resonant stage power components are SMT, like most of the passive components, therefore decreasing production costs. The board also has protections in case of overload or short-circuit, open-loop by each stage, or input overvoltage. Because of the particular application, all protections, in the case of intervention, are auto-restart. Figure 1. September 2012 EVL130W-SL-EU: 130 W SMPS for LED street lighting applications Doc ID 16774 Rev 2 1/30 www.st.com Contents AN3105 Contents 1 Main characteristics and circuit description . . . . . . . . . . . . . . . . . . . . . 4 1.1 Power Factor corrector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.2 Resonant power stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.3 Startup sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.4 Output voltage feedback loop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.5 L6599AT overload and short-circuit protection . . . . . . . . . . . . . . . . . . . . . . 6 1.6 Overvoltage and open-loop protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2 Efficiency measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3 Input current harmonics measurement . . . . . . . . . . . . . . . . . . . . . . . . . . 9 4 Functional check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 4.1 PFC circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 4.2 Half-bridge resonant LLC circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 4.3 Dynamic load operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 4.4 Overcurrent and overvoltage protection . . . . . . . . . . . . . . . . . . . . . . . . . . 14 4.5 Converter startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 4.6 Thermal map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 5 Conducted emission pre-compliance test: peak measurement . . . . . 19 6 Bill of material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 7 PFC coil specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 8 Transformer specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 9 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 2/30 Doc ID 16774 Rev 2 AN3105 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. EVL130W-SL-EU: 130 W SMPS for LED street lighting applications. . . . . . . . . . . . . . . . . . 1 EVL130W-SL-EU demonstration board: electrical diagram . . . . . . . . . . . . . . . . . . . . . . . . . 7 EVL130W-SL-EU demonstration board efficiency diagrams . . . . . . . . . . . . . . . . . . . . . . . . 8 EVL130W-SL-EU demonstration board: compliance to EN61000-3-2 Class-C standard . . 9 EVL130W-SL-EU demonstration board: input current waveform at 230 V - 50 Hz - 130 W load and 65 W load. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 EVL130W-SL-EU demonstration board: Power Factor and Total Harmonic Distortion vs. load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 EVL130W-SL-EU demonstration board: PFC stage and L6562AT waveforms at 230 V 50 Hz - full load – detail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 EVL130W-SL-EU demonstration board: primary and secondary side resonant stage waveforms at 230 V - 50 Hz - full load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 EVL130W-SL-EU demonstration board: high and low frequency ripple on output voltage at 230 V - 50 Hz - full load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 EVL130W-SL-EU demonstration board: output voltage variation driving a CC LED converter - PWM = 90% and PWM = 15% . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 EVL130W-SL-EU demonstration board: short-circuit at 230 VAC - 50 Hz - full load and open loop protection intervention at 20 W load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 EVL130W-SL-EU demonstration board: startup at 230 VAC - 50 Hz - full load . . . . . . . . . 16 Thermal map at 230 VAC - 50 Hz - full load - PCB top side . . . . . . . . . . . . . . . . . . . . . . . . 17 Thermal map at 230 VAC - 50 Hz - full load - PCB bottom side . . . . . . . . . . . . . . . . . . . . . 18 CE peak measure at 230 VAC and full load - phase wire . . . . . . . . . . . . . . . . . . . . . . . . . . 19 CE peak measure at 230 VAC and full load - neutral wire . . . . . . . . . . . . . . . . . . . . . . . . . 19 PFC coil electrical diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 PFC coil mechanical aspect(1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Transformer electrical diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Transformer overall drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Doc ID 16774 Rev 2 3/30 Main characteristics and circuit description 1 AN3105 Main characteristics and circuit description The main features of the SMPS are: 1.1 ● Extended European input mains range: 177 to 277 VAC - frequency 45 to 55 Hz ● Output voltage: 48 V at 2.7 A ● Long-life electrolytic capacitors are not used ● Mains harmonics: acc. to EN61000-3-2 Class-C ● Efficiency at full load: better than 90% ● EMI: according to EN55022-Class-B ● Safety: double insulation, according to EN60950, SELV ● Dimensions: 75 x 135 mm, 30 mm components maximum height ● No heatsinks needed ● PCB: single side, 35 µm, FR-4, mixed PTH/SMT Power Factor corrector The PFC stage, working in transition mode, acts as a pre-regulator and powers the resonant stage with the output voltage of 450 V. The PFC power topology is a conventional boost converter, connected to the output of the rectifier bridge D3. It is completed by the coil L1, manufactured by MAGNETICA, the diode D2 and the capacitors C5, C6, and C7 in parallel. The PFC output capacitors are film type, 5 µF - 800 V, manufactured by EPCOS. Using film capacitors to replace the typical electrolytic capacitors considerably increases the MTBF of the board. The boost switch is represented by the Power MOSFET Q2. The board is equipped with an input EMI filter necessary to filter the commutation noise coming from the boost stage. The PFC implements the L6562AT controller, a small and inexpensive controller which is guaranteed for operation over a wide temperature range. At startup, the L6562AT is supplied by the startup resistors R5, R8, and R13 charging the capacitor C13; once the PFC begins switching, a charge pump connected to the auxiliary winding of the PFC inductor L1 supplies both PFC and resonant controllers via a small linear regulator realized by Q1. Once both stages have been activated, the controllers are also supplied by the auxiliary winding of the resonant transformer, assuring correct supply voltage during all load condition operations. The L1 auxiliary winding is also connected to the L6562AT pin #5 (ZCD) through the resistor R18. Its purpose is to provide the information that L1 has demagnetized, needed by the internal logic to trigger a new switching cycle. The PFC boost peak current is sensed by resistor R34 in series to the MOSFET source; the signal is fed into pin #4 (CS) of the L6562AT, via the filter R27 and C16. The dividers R7, R12, R14, and R22 provide the information on the instantaneous mains voltage to the L6562AT multiplier which is used to modulate the peak current of the boost. The resistors R2, R6, R9 with R15 and R16 are dedicated to sensing the output voltage and feed, to the L6562AT, the feedback information necessary to keep the output voltage regulated. The components C11 and R20 (C12 is shorted) make up the error amplifier compensation network necessary to keep the required loop stability. 4/30 Doc ID 16774 Rev 2 AN3105 1.2 Main characteristics and circuit description Resonant power stage The down-stream converter is a resonant LLC half-bridge stage working with 50 percent fixed duty cycle and variable frequency. It implements the ST L6599AT, integrating all functions necessary to properly control the resonant topology. The resonant transformer, manufactured by MAGNETICA, uses the integrated magnetic approach, so the leakage inductance is used for resonant operation of the circuit. Therefore, no external, additional coil is needed for the resonance. The transformer secondary winding configuration is the typical centre tap, using a couple of type STPS10150CG power Schottky rectifiers. The output capacitors are film type, 4.7 µF - 63 V from EPCOS. Like for the PFC stage, using film capacitors allows to increase considerably the MTBF of the board. A small LC filter has been added on the output, in order to filter the high frequency ripple. D21, D22, and R55 implement a voltage controlled bleeder; in the case of no-load operation of the SMPS, this circuit provides a bleeder limiting the increase of output voltage, but not affecting efficiency during normal operation. Please note that the converter has not been designed to work in this condition and therefore its mains consumption is not optimized (~3 W). 1.3 Startup sequence The PFC acts as master and therefore starts first; the resonant stage operates only if the PFC is delivering the nominal output voltage to prevent the resonant converter from working with a too low input voltage which can cause incorrect capacitive mode operation. Therefore both stages are designed to work according to this sequence. For correct sequencing, the L6599AT makes use of the LINE pin (#7) to sense the PFC output voltage via a resistor divider. The L6599AT LINE pin (#7) has an internal comparator which has a hysteresis allowing the turn-on and turn-off voltage to be set independently. At startup, the LLC stage starts once the PFC output voltage reaches ~ 430 V, while the turnoff threshold has been set to ~ 330 V. 1.4 Output voltage feedback loop The output voltage is kept stable by means of a feedback loop implementing a typical circuit using a TS2431 to modulate the current in the optocoupler diode. On the primary side, R43 - connecting pin RFMIN (#4) to the optocoupler's phototransistor allows the L6599AT oscillator frequency to be modulated, therefore keeping the output voltage regulated. It also sets the maximum switching frequency at about 130 kHz. R42, which connects the same pin to ground, sets the minimum switching frequency. The R-C series R37 and C24 sets both soft-start maximum frequency and duration. All demonstration boards implement the voltage loop circuitry described above but in case a current loop is also required it can be achieved by implementing the following modifications: ● Replace R30 and R31 0R0 Ω resistors with sensing resistors, 0R033 and 0R039 respectively, both 0805 ● Populate on PCB U4 and the relevant components reported on the schematic as N.M.: C36 = 1N0-0805; C37 = 100NF-0805; R51 = 15R-0805; R56 = 1K0-0805; R61 =22K1206; C41 = 2N2-0805; U5 = SEA05TR ● Remove the TS2431AILT Doc ID 16774 Rev 2 5/30 Main characteristics and circuit description AN3105 With these modifications the circuit is able to keep the output current constant at 2.7 A down to an output voltage value of around 30 V. This function can be used to optimize the voltage drop and power dissipation in case current linear regulators are used to regulate the current flowing in each LED strip. In case the output current is lower than the current loop setpoint, the voltage loop takes over the operation regulating the output voltage at its nominal value, like using the TS2431AILT. 1.5 L6599AT overload and short-circuit protection The current flowing into the primary winding, proportional to the output load, is sensed by the lossless circuit C34, R53, D19, D18, R57, and C35 and it is fed into the ISEN pin (#6) of L6599AT. In the case of overcurrent, the voltage on the pin overpasses an internal threshold (0.8 V), triggering a protection sequence. The capacitor (C21) connected to the DELAY pin (#2) is charged by an internal 150 µA current generator. If the voltage on the pin reaches 2 V, the soft-start capacitor is completely discharged so that the switching frequency is pushed to its maximum value. As the voltage on the pin exceeds 3.5 V the IC stops switching and the internal generator is turned off, so that the voltage on the DELAY pin decays because of the external resistor connected between the pin and GND. The L6599AT is soft-restarted as the voltage drops below 0.3 V. In this way, under short-circuit conditions, the converter works intermittently with low input average power, limiting the stress of components during shorts. 1.6 Overvoltage and open-loop protection Both circuit stages, PFC and resonant, are equipped with their own overvoltage protections. The L6562AT PFC controller implements an overvoltage protection against the output voltage variation due to the poor bandwidth of the error amplifier, happening in the case of transients. Unfortunately it cannot protect the circuit in the case of a feedback loop failure such as disconnection or deviation from the nominal value of the feedback loop divider. In the case where a similar failure condition is detected, the L6599AT pin DIS (#8) stops the operation and also stops the PFC operation by means of the L6599AT pin PFC_STOP (#9) connected to the L6562AT pin INV (#1). The converter operation is latched until the VCC capacitors are discharged, then a new startup sequence takes place automatically and the converter resumes operation if the failure is removed or a new sequence is triggered. The same sequence occurs also in the case of input voltage transients which may damage the converter. The DIS pin is also used to protect the resonant stage against loop failures. The Zener diode D17 detects the auxiliary voltage generated by the LLC transformer. In the case of loop failure, it conducts, and voltage on the DIS pin exceeds the internal threshold, latching off the device. The L6562AT operation is also stopped by the PFC_STOP pin as in the previous case, and after some time has elapsed the circuit restarts. 6/30 Doc ID 16774 Rev 2 FUSE T4A F1 R47 VCC RX2 R22 Doc ID 16774 Rev 2 1 1 C15 15 nF 2 3 Z1 1 2 N. M. R49 R42 C24 N. M. R44 5 6 7 R37 VCC ZCD GND GD 8 C13 220 nF C32 R43 C9 10 nF 9 11 R52 1 2 2 1 8 7 6 5 R33 N. M. JUMPER D23/JPX9 DIS LINE ISEN STBY RFMIN CF 1 PFC-STOP GND LV CC V NC OUT HVG VBOOT R21 D7 BZV55-B15 R23 DELAY CSS D1 1N4007 R11 3 L6599AT U2 D9 LL4148 C25 3 470 pF 4 D14 R32 R18 D8 LL4148 Q1 BC847C C10 D4 LL4148 5 3 L1 1974.0001 D5 LL4148 R3 D17 BZV55-B24 10 nF C33 C26 4.7 nF LL4148 R36 C21 220 nF R27 R38 R13 R8 R5 C4 470 nF-X2 VCC C31 220 nF R1 MULT CS U1 R16 _ L6562AT COMP INV Q3 3 N. M. VIN ~ C16 220 pF 4 3 2 1 R15 D10 Q7 BC847C D3 GBU8J C3 470 nF-X2 N. M. R20 C11 220 nF C12 4 PCB rev. 0.2 3 C2 470 nF-X2 Q8 2 BC847C 3 R45 R14 R12 R7 177-277 VAC 1 2 L2 2019.0002 1 R34 9 10 11 12 13 VCC 14 15 C22 100 nF 16 3 C30 Q2 2 STF22NM60N D6 LL4148 D2 STTH3L06U D24 LL4148 220 nF R26 VIN R39 R57 R46 1 1 C5 C6 C40 D19 LL4148 RX1 R53 3 Q4 STD10NM60N 2 3 Q5 STD10NM60N 2 D18 LL4148 D13 LL4148 R19 R17 R24 R10 D16 LL4148 C35 R25 R9 R6 R2 R4 C34 R59 220 pF D20 STPS1L60A GB6 C7 15 nF C20 13 12 14 10 8 9 11 REV. 0.9 U3 3 4 R62 2 1 2 1 C18 C39 470 nF N. M. R54 R60 R58 R41 3 U5 TS2431AILT C38 R50 D22 D21 C41 R61 1 N. M. 3 N. M. 2 R56 N. M. R51 N. M. Vctrl Ictrl OUT 4 5 I.sense VCC 6 GND 1 2 N.M. C36 C37 N. M. 48 V at 2.7 A 100 nF C19 J2 MKDS 1,5/ 2-5,08 U4 SEA05 - N. M. R31 R30 L3 R55 R29 N. M. BZV55-B24 BZV55-B24 Q6 BC847C C17 BZV55-B24 D15 D11 STPS10150CG D12 STPS10150CG C27 220 nF SFH617A-2X009 7 6 4 2 T1 1860.0013 C8 2.2 nF - Y1 C1 2.2 nF - Y1 Figure 2. 2 RV1 300 VAC MKDS 1,5/ 3-5,08 ~ 3 + J1 AN3105 Main characteristics and circuit description EVL130W-SL-EU demonstration board: electrical diagram AM00868 7/30 Efficiency measurement 2 AN3105 Efficiency measurement Table 1 shows the overall efficiency, measured at 230 VAC - 50 Hz with different loads. At 230 VAC and full load the overall efficiency is 93.85%, making this design suitable for high efficiency power supplies. The efficiency has been measured at 25%, 50%, 75%, and 100%, the average efficiency calculated according to the ES-2 standard is 91.56%. Table 1. EVL130W-SL-EU demonstration board: overall efficiency vs. load 230 V-50 Hz Load VOUT [V] IOUT [A] POUT [W] PIN [W] Efficiency [%] 25% load 47.59 0.682 32.46 37.14 87.39% 50% load 47.55 1.37 65.14 70.89 91.89% 75% load 47.54 2.00 95.08 102.1 93.12% 100% load 47.54 2.74 130.26 138.8 93.85% Average efficiency 91.56% The measured output voltage at different load conditions is reported in Table 1. As seen, the voltage is very stable over all the output load range. The measured efficiency is shown on the lefthand side of the graph in Figure 3, while on the righthand side of Figure 3 the efficiency, at maximum load and at minimum, nominal, and maximum AC input voltage, is reported. Figure 3. EVL130W-SL-EU demonstration board efficiency diagrams %FFICIENCYVS6!# %FFICIENCY %FFICIENCY %FFICIENCYVSLOAD ,OAD 8/30 6!#;6RMS= Doc ID 16774 Rev 2 !- AN3105 Input current harmonics measurement 3 Input current harmonics measurement One of the main purposes of a PFC pre-conditioner is the correction of input current distortion, decreasing the harmonic contents below the limits of the relevant regulations. Therefore, this demonstration board has been tested according to the European standard EN61000-3-2 Class-C relevant to lighting equipment, at full load and nominal input voltage mains. Measurement results are in Figure 4 - on the lefthand side. The circuit shows its ability to reduce the harmonics, also well below the limits of EN61000-3-2 Class-C regulation, not only at full load but also at significant lower load; on the righthand side of Figure 4 the input current harmonics measurement at light load (minimum input power to be compliant with the above mentioned rule is 25 W) shows that even if the power supply is working out of its typical operating region it is still compliant with the EN61000-3-2 Class-C limits. Figure 4. EVL130W-SL-EU demonstration board: compliance to EN61000-3-2 Class-C standard (ARMONICCURRENT;!= (ARMONICCURRENT;!= (ARMONICORDER;N= (ARMONICORDER;N= -EASUREDVALUE %.#LASS#LIMITS !- VIN = 230 VAC - 50 Hz, POUT = 130 W THD = 6.85%, PF = 0.981 VIN = 230 VAC - 50 Hz, PIN = 26.7 W THD = 10.3%, PF = 0.753 Doc ID 16774 Rev 2 9/30 Input current harmonics measurement AN3105 For user reference, waveforms of the input current and voltage at nominal input voltage mains full load and 50% load conditions are given in Figure 5. Figure 5. EVL130W-SL-EU demonstration board: input current waveform at 230 V - 50 Hz - 130 W load and 65 W load CH1: VIN AC CH1: VIN AC CH4: I_AC CH4: I_AC The “Power Factor” (PF) and the “Total Harmonic Distortion” (THD) versus load variations have also been measured and the results are given in Figure 6. As seen, the Power Factor remains close to unity and the Total Harmonic Distortion is very low. Figure 6. EVL130W-SL-EU demonstration board: Power Factor and Total Harmonic Distortion vs. load 4($VSLOAD 4($ 0OWER&ACTOR 0OWER&ACTORVSLOAD ,OAD ,OAD !- 10/30 Doc ID 16774 Rev 2 AN3105 Functional check 4 Functional check 4.1 PFC circuit On the lefthand side of Figure 7, some waveforms relevant to the PFC stage have been captured; the envelope of CS pin (#4) waveforms of the L6562AT is in phase with the MULT pin (3#) and has the same sinusoidal shape, demonstrating the correct functioning of the PFC stage. It is also possible to measure the peak-to-peak value of voltage ripple over imposed to the PFC output voltage; this is due to the low value of the PFC output capacitors. On the righthand side of Figure 7 the details of some waveforms at switching frequency are given. Figure 7. EVL130W-SL-EU demonstration board: PFC stage and L6562AT waveforms at 230 V 50 Hz - full load – detail CH2: VOUT PFC CH4: MULT 4.2 CH3: CS CH3: CS CH1: Vdrain_Q2 CH4: ZCD CH2: VOUT PFC Half-bridge resonant LLC circuit Some waveforms relevant to the resonant stage during steady-state operation are given in the following pages. The resonant stage switching frequency is about 100 kHz, in order to have a good trade off between transformer losses and dimensions. The LLC converter has been designed to operate at nominal voltage and full load at the resonance frequency, but due to the PFC output voltage ripple at twice the mains frequency it is driven slightly above and below the resonant tank frequency, according to the instantaneous value of PFC output voltage. In Figure 8 (on the lefthand side) some waveforms relevant to the resonant stage ZVS operation are shown; it is possible to see that both MOSFETs are turned on when resonant current is flowing through their body diodes and therefore drain-source voltage is almost zero, achieving good efficiency because the turn-on losses are negligible. The HB MOSFET voltage de-rating and low operating temperature allow the board MTBF to be increased. The current flowing in the resonant tank is sinusoidal; in Figure 8 it is possible to appreciate a slight asymmetry of operating modes by each half portion of the sinewave; half cycle is working at resonant frequency while the other is working above the resonant frequency. This Doc ID 16774 Rev 2 11/30 Functional check AN3105 is due to a small difference between each half-secondary leakage inductance of the transformer reflected to the primary side, providing the two slightly different resonant frequencies. This phenomenon is typically due to a different coupling of transformer secondary windings and in this case it is not an issue. The slight asymmetry can also be appreciated in Figure 8 (on the righthand side); the small ringing appearing on both secondary rectifiers anode voltage indicates that for a short time the rectifiers are not conducting; it demonstrates that during half cycle the circuit is working below the resonant frequency while during the following half cycle it is working at resonance frequency. In Figure 8 it is also possible to appreciate the rectifier operating voltage and its margin with respect to the maximum reverse voltage (VRRM). This de-rating with respect to the rectifiers VRRM guarantees good reliability of the output rectifiers increasing the board total MTBF. Figure 8. EVL130W-SL-EU demonstration board: primary and secondary side resonant stage waveforms at 230 V - 50 Hz - full load CH1: HB voltage CH3: VCC 12/30 CH2: CF pin voltage CH4: res. tank current CH1: V_D12 CH3: VOUT Doc ID 16774 Rev 2 CH2: V_D11 AN3105 Functional check On the lefthand side of Figure 9 the high frequency ripple has been measured; as seen the ripple and noise at switching frequency is very limited, thanks to the low EMI generated by both stages. On the righthand side of Figure 9 the low frequency ripple has also been measured. It is possible to note that the peak-to-peak value is not so low but it doesn't affect the application, in fact the converters regulating the current flowing in each LED strip can reject the ripple without any problem. Figure 9. CH3: VOUT 4.3 EVL130W-SL-EU demonstration board: high and low frequency ripple on output voltage at 230 V - 50 Hz - full load CH1: HB voltage CH3: VOUT Dynamic load operation Waveforms reported in Figure 10 are relevant to the demonstration board during operation, supplying converters dedicated to power LED strips with constant current. In both figures it is possible to see the output voltage modulation during operation with variable load due to the dimming of the LED current by PWM. For both measurements, a dimming frequency of 300 Hz has been chosen. On the lefthand side of Figure 10 the converter output current was 2.6 A and dimming duty cycle was 90%, therefore very close to the converter nominal output power. The output voltage in the image has two modulations; one is due to the rejection of the PFC output voltage ripple already measured in Figure 9, on the righthand side. Over imposed there is the voltage variation due to the LED current dimming. The peak-to-peak variation is 5.37 V, this doesn't create any problems for the load as the converters reject the modulation. Whereas on the righthand side of Figure 10 the converter has been checked at light load, so the peak output current was 3 A and dimming duty cycle was 15%, for an output power of 21 W. Even in this case the peak-to-peak modulation doesn't give any trouble to the downstream current regulators and the board still works correctly. Doc ID 16774 Rev 2 13/30 Functional check AN3105 Figure 10. EVL130W-SL-EU demonstration board: output voltage variation driving a CC LED converter - PWM = 90% and PWM = 15% CH1: PWM dimming signal CH4: SMPS output current CH2: VOUT CH1: PWM dimming signal CH4: SMPS output current CH2: VOUT It is worth clarifying that, for correct operation with LED strips, the board needs some additional capacitors connected on the +48 V output bus. It has not been equipped with all the capacitors necessary for correct operation with LEDs but only with minimum capacitance to allow board operation, in order to optimize the system cost and reliability. The additional capacitors needed are intended to be placed close to each LED strip current regulator, therefore filtering the EMI generated by these. In several cases, in fact, the power supply is placed at the base of the lighting pole while the LED current regulators are located on top, in the lamp. The long wiring connection between the power supply and the converters can act as an antenna radiating EMI. Therefore local filtering minimizes the radiated EMI. The capacitance to be added to the 48 V bus, for correct operation with LEDs, is around 40 µF. In order to not affect the board MTBF, using the same capacitor type already used on the power supply board is suggested. 4.4 Overcurrent and overvoltage protection The L6599AT is equipped with a current sensing input (pin #6, ISEN) and a dedicated overcurrent management system. The current flowing in the resonant tank is detected and the signal is fed into the ISEN pin. It is internally connected to a first comparator, referenced to 0.8 V, and to a second comparator referenced to 1.5 V. If the voltage externally applied to the pin exceeds 0.8 V, the first comparator is tripped causing an internal switch to be turned on and discharging the soft-start capacitor C24 (CSS). Under output short-circuit, this operation results in a nearly constant peak primary current. With the L6599AT the designer can program externally the maximum time that the converter is allowed to run overloaded or under short-circuit conditions. Overloads or short-circuits lasting less than the set time do not cause any other action, and so provide the system with immunity to short duration phenomena. If, instead, an overload condition continues, a protection procedure is activated which shuts down the L6599AT. In the case of continuous overload or short-circuit, it results in continuous intermittent operation with a user defined duty cycle. 14/30 Doc ID 16774 Rev 2 AN3105 Functional check This function is realized with the DELAY pin (#2), by means of a capacitor C21 and the parallel resistor R32 connected to ground. As the voltage on the ISEN pin exceeds 0.8 V the first OCP comparator, in addition to discharging CSS, turns on an internal 150 µA current generator that via the DELAY pin charges C21. When the voltage on C21 is 3.5 V, the L6599AT stops switching and the PFC_STOP pin (#9) is pulled low, also turning off the PFC stage via the L6562AT pin #1 (INV). Also the internal generator is turned off, so that C21 is now slowly discharged by R32. The IC restarts once the voltage on C21 is less than 0.3 V. Additionally, if the voltage on the ISEN pin reaches 1.5 V for any reason (e.g. transformer saturation), the second comparator is triggered, the L6599AT shuts down and the operation is resumed after recycling the VCC. In this demonstration board the intervention of the second level comparator latches the operation of the L6599AT and the PFC_STOP pin (#9) stops the PFC. Both controllers are no longer powered by VCC and the latch is removed, then a new startup cycle takes place. This sequence lasts until the short is removed. On the lefthand side of Figure 11 the operation of the DELAY pin and the consequent hiccup mode operation of the board during short-circuit operation can be seen. Thanks to the narrow operating time, with respect to the off time, the average output current, as well as the average primary current, are limited. This avoids converter overheating and consequent failures. At short removal the board resumes normal operation. Figure 11. EVL130W-SL-EU demonstration board: short-circuit at 230 VAC - 50 Hz - full load and open loop protection intervention at 20 W load CH1: V_OUT_PFC CH4: DELAY pin CH2: HB voltage CH3: VOUT CH1: Q1_Drain CH4: DIS pin CH2: HB voltage On the righthand side of Figure 11 the operation of the demonstration board during “openloop” operation by the LLC stage is shown. The open-loop operation also provides an increase of the auxiliary voltage which triggers the L6599AT pin #9 (DIS) protection pin via the Zener diode D17. As a consequence, the L6599AT shuts down, stopping the operation. The L6599AT also activates the PFC_STOP pin (#9) which also stops the PFC, therefore both controllers are no longer powered by VCC. Once VCC drops below the UVLO the latch is removed and a new startup cycle takes place. This sequence lasts until the open-loop is removed. Doc ID 16774 Rev 2 15/30 Functional check 4.5 AN3105 Converter startup On the lefthand side of Figure 12 the converter startup is shown. It is possible to note that at nominal input voltage the converter begins operation in ~150 ms. This is the time needed to charge the VCC to the L6562AT turn-on voltage. Therefore the L6562AT starts switching and the PFC output voltage starts increasing. Once the PFC output voltage reaches the enable level set via the L6599AT LINE pin (~ 430 V), even the LLC stage starts switching and the output voltage rises up to the nominal level. The VCC is initially supplied by the PFC coil charge pump, and then, once the L6599AT starts operating, the VCC is also provided by the LLC transformer auxiliary winding. Details of converter sequencing can be found on the righthand side of Figure 12. Figure 12. EVL130W-SL-EU demonstration board: startup at 230 VAC - 50 Hz - full load CH1: Q2_Drain CH2: HB voltageCH1: Q2_DrainCH2: HB voltage CH3: L6562AT VCC CH4: VOUTCH3: L6599AT VCC pin CH4: VOUT Figure 12 shows a correct startup of the board using an active load, with only the capacitors for the 48 V populating the board. When powering current regulators with LEDs it is possible that the board may show an incorrect startup, with output voltage going up and down and the LEDs flashing. As already explained in Section 4.3: Dynamic load operation, the board needs an additional 40 µF capacitance on the +48 V. 16/30 Doc ID 16774 Rev 2 AN3105 4.6 Functional check Thermal map In order to check the design reliability, a thermal mapping by means of an IR camera was done. In Figure 13 and 14 the thermal measurements of the board, both sides, at nominal input voltage are shown. Some pointers visible on the images have been placed across key components. The ambient temperature during both measurements was 27 °C. Figure 13. Thermal map at 230 VAC - 50 Hz - full load - PCB top side Table 2. Thermal maps reference points - PCB top side Point Reference Description A L2 EMI filtering inductor B L1 PFC inductor C D3 Bridge rectifier D Q2 PFC MOSFET E L3 Output filter inductor F T1 Resonant power transformer - primary winding G T1 Resonant power transformer - ferrite core H T1 Resonant power transformer - secondary winding Doc ID 16774 Rev 2 17/30 Functional check AN3105 Figure 14. Thermal map at 230 VAC - 50 Hz - full load - PCB bottom side Table 3. Point 18/30 Thermal maps reference points - PCB bottom side Reference Description A Q4 LLC resonant HB MOSFET B Q5 LLC resonant HB MOSFET C D2 PFC output diode D D12 Output rectifier E D11 Output rectifier Doc ID 16774 Rev 2 AN3105 5 Conducted emission pre-compliance test: peak measurement Conducted emission pre-compliance test: peak measurement Figure 15 and 16 show the peak measurement of the conducted noise at full load and nominal mains voltage. The limits on the diagrams are the EN55022 Class-B. As seen in the diagrams, for both input wires the measurements are well below the limits. Figure 15. CE peak measure at 230 VAC and full load - phase wire Figure 16. CE peak measure at 230 VAC and full load - neutral wire Doc ID 16774 Rev 2 19/30 Bill of material AN3105 6 Bill of material Table 4. EVL130W-SL-EU demonstration board: bill of material Des. Part type/ part value Case style/ package Description Supplier C1 2N2-Y1 4.5 x 12.0 p.10 mm Y1 safety cap. DE1E3KX222M Murata C10 1 µF 1206 50 V CERCAP - general purpose - X7R - 10% TDK© C11 220 nF 0805 16 V CERCAP - general purpose - X7R - 10% Murata C12 0R0 0805 SMD standard film res. - 1/8 W - 1% - 100 ppm/°C VISHAY® C13 10 µF 1210 25 V CERCAP - general purpose - X7R - 20% TDK C15 15 nF 0805 50 V CERCAP - general purpose - X7R - 10% KEMET C16 220 pF 0805 50 V CERCAP - general purpose - COG - 5% KEMET C17 4.7 µF 7.8 x 7.8 p. 5 63 V - MKT film cap. - B32529D0475M000 EPCOS C18 4.7 µF 7.8 x 7.8 p. 5 63 V - MKT film cap. - B32529D0475M000 EPCOS C19 100 nF 0805 100 V CERCAP - general purpose - X7R - 10% AVX C2 470 nF - X2 9.0 × 18.0 p.15 mm X2 - MKP film cap. - B32922C3474K EPCOS C20 15 nF DWG - 5 x 18 p.15 mm 1000 V - MKP film cap. - B32652A0153K000 EPCOS C21 220 nF 0805 16 V CERCAP - general purpose - X7R - 10% Murata C22 100 nF 1206 50 V CERCAP - general purpose - X7R - 10% KEMET C24 4.7 µF 0805 6.3 V CERCAP - general purpose - X5R - 10% EPCOS C25 470 pF 0805 50 V CERCAP - general purpose - COG - 5% EPCOS C26 4.7 nF 0805 50 V CERCAP - general purpose - X7R - 10% KEMET C27 220 nF 0805 50 V CERCAP - general purpose - X7R - 10% Murata C3 470 nF - X2 9.0 × 18.0 p. 15 mm X2 - MKP film cap. - B32922C3474K EPCOS C30 10 µF 1210 25 V CERCAP - general purpose - X7R - 20% TDK C31 220 nF 0805 16 V CERCAP - general purpose - X7R - 10% Murata C32 220 nF 0805 16 V CERCAP - general purpose - X7R - 10% Murata C33 10 nF 0805 50 V CERCAP - general purpose - X7R - 10% KEMET C34 220 pF 1206 1 KV high voltage CERCAP - X7R - 10% AVX C35 220 nF 0805 16 V CERCAP - general purpose - X7R - 10% Murata C36 N. M. 0805 Not mounted C37 N. M. 0805 Not mounted C38 N. M. 0805 Not mounted 20/30 Doc ID 16774 Rev 2 AN3105 Bill of material Table 4. Des. EVL130W-SL-EU demonstration board: bill of material (continued) Part type/ part value Case style/ package Description Supplier C39 470 nF 0805 25 V CERCAP - general purpose - X7R - 10% KEMET C4 470 nF - X2 9.0 × 18.0 p.15 mm X2 - MKP film cap. - B32922C3474K EPCOS C40 10 µF 2220 50 V - CERCAP - general purpose - X7R - 20% TDK C41 N. M. 0805 Not mounted C5 5 µF 14 × 31.5 p.27.5 mm 800 V - MKP film cap. - B32774D8505K000 EPCOS C6 5 µF 14 × 31.5 p. 27.5 mm 800 V - MKP film cap. - B32774D8505K000 EPCOS C7 5 µF 14 × 31.5 p. 27.5 mm 800 V - MKP film cap. - B32774D8505K000 EPCOS C8 2.2 nF - Y1 4.5 x 12 p.10 mm Y1 safety cap. DE1E3KX222M Murata C9 10 nF 1206 100 V CERCAP - general purpose - X7R - 10% KEMET D1 1.4007 nF DO-41 General purpose rectifier VISHAY D10 N. M. SOD-80 Not mounted D11 STPS10150CG D2PAK Power Schottky rectifier STMicroelectronics™ D12 STPS10150CG D2PAK Power Schottky rectifier STMicroelectronics D13 LL4148 SOD-80 Fast switching diode VISHAY D14 LL4148 SOD-80 Fast switching diode VISHAY D15 BZV55-B24 SOD-80 Zener diode VISHAY D16 LL4148 SOD-80 Fast switching diode VISHAY D17 BZV55-B24 SOD-80 Zener diode VISHAY D18 LL4148 SOD-80 Fast switching diode VISHAY D19 LL4148 SOD-80 Fast switching diode VISHAY D2 STTH3L06U SMB Ultrafast high voltage rectifier STMicroelectronics D20 STPS1L60A SMA Fast switching diode STMicroelectronics D21 BZV55-B24 SOD-80 Zener diode VISHAY D22 BZV55-B24 SOD-80 Zener diode VISHAY JPX9 JUMPER /D23 Wire jumper D24 LL4148 SOD-80 Fast switching diode D3 GBU8J STYLE GBU Single-phase bridge rectifier DWG VISHAY D4 LL4148 SOD-80 Fast switching diode VISHAY D5 LL4148 SOD-80 Fast switching diode VISHAY D6 LL4148 SOD-80 Fast switching diode VISHAY Doc ID 16774 Rev 2 VISHAY 21/30 Bill of material Table 4. Des. AN3105 EVL130W-SL-EU demonstration board: bill of material (continued) Part type/ part value Case style/ package Description Supplier D7 BZV55-B15 SOD-80 Zener diode VISHAY D8 LL4148 SOD-80 Fast switching diode VISHAY D9 LL4148 SOD-80 Fast switching diode VISHAY F1 FUSE T4A 8.5 x 4 p. 5.08 Fuse 4 A - time lag - 3921400 mm Littlefuse J1 MKDS 1,5/ 3-5,08 p. 5.08 mm PCB term. block, screw conn., pitch 5 mm - 3 W. PHOENIX CONTACT J2 MKDS 1,5/ 2-5,08 p. 5. 08 mm PCB term. block, screw conn., pitch 5 mm - 2 W. PHOENIX CONTACT L1 1974.0001 DWG PFC choke - 520 µH PQ26/20 MAGNETICA L2 12 mH DWG CM filter 2019.0002 MAGNETICA L3 3.3 µH - 4.7 A Dia. 7.7 p. 5 mm Inductor 1071.0080 MAGNETICA Q1 BC846C SOT-23 NPN small signal BJT VISHAY Q2 STF22NM60N TO220 N-channel Power MOSFET STMicroelectronics Q3 N. M. SOT-23 Not mounted Q4 STD10NM60N DPAK N-channel Power MOSFET STMicroelectronics Q5 STD10NM60N DPAK N-channel Power MOSFET STMicroelectronics Q6 BC846C SOT-23 NPN small signal BJT VISHAY Q7 BC846C SOT-23 NPN small signal BJT VISHAY Q8 BC846C SOT-23 NPN small signal BJT VISHAY R1 N. M. 0805 Not mounted R10 1.2 MΩ 1206 SMD standard film res. - 1/4 W - 1% - 100 ppm/°C VISHAY R11 4.7 KΩ 1206 SMD standard film res. - 1/4 W - 5% - 250 ppm/°C VISHAY R12 2.0 MΩ 1206 SMD standard film res. - 1/4 W - 5% - 250 ppm/°C VISHAY R13 120 KΩ 1206 SMD standard film res. - 1/4 W - 5% - 250 ppm/°C VISHAY R14 390 KΩ 1206 SMD standard film res. - 1/4 W - 5% - 250 ppm/°C VISHAY R15 39 KΩ 0805 SMD standard film res. - 1/8 W - 1% - 100 ppm/°C VISHAY R16 39 KΩ 0805 SMD standard film res. - 1/8 W - 1% - 100 ppm/°C VISHAY R17 0Ω 1206 SMD standard film res. - 1/4 W - 1% - 100 ppm/°C VISHAY R18 56 KΩ 1206 SMD standard film res. - 1/4 W - 5% - 250 ppm/°C VISHAY R19 0Ω 0805 SMD standard film res. - 1/8 W - 1% - 100 ppm/°C VISHAY R2 1.0 MΩ 1206 SMD standard film res. - 1/4 W - 1% - 100 ppm/°C VISHAY R20 680 KΩ 0805 SMD standard film res. - 1/8 W - 5% - 250 ppm/°C VISHAY R21 33 Ω 0805 SMD standard film res. - 1/8 W - 5% - 250 ppm/°C VISHAY 22/30 Doc ID 16774 Rev 2 AN3105 Bill of material Table 4. Des. EVL130W-SL-EU demonstration board: bill of material (continued) Part type/ part value Case style/ package Description Supplier R22 15 KΩ 0805 SMD standard film res. - 1/8 W - 5% - 250 ppm/°C VISHAY R23 100 Ω 0805 SMD standard film res. - 1/8 W - 5% - 250 ppm/°C VISHAY R24 1.4 MΩ 1206 SMD standard film res. - 1/4 W - 1% - 100 ppm/°C VISHAY R25 82 KΩ 0805 SMD standard film res. - 1/8 W - 1% - 100 ppm/°C VISHAY R26 15 KΩ 0805 SMD standard film res. - 1/8 W - 1% - 100 ppm/°C VISHAY R27 470 Ω 0805 SMD standard film res. - 1/8 W - 5% - 250 ppm/°C VISHAY R29 N. M. 1206 Not mounted R3 10 Ω 1206 SMD standard film res. - 1/4 W - 5% - 250 ppm/°C VISHAY R30 0Ω 1206 SMD standard film res. - 1/4 W - 1% - 100 ppm/°C VISHAY R31 0Ω 1206 SMD standard film res. - 1/4 W - 1% - 100 ppm/°C VISHAY R32 270 KΩ 0805 SMD standard film res. - 1/8 W - 5% - 250 ppm/°C VISHAY R33 N. M. 2010 Not mounted R34 0.39 Ω 2010 SMD standard film res. - 1/2 W - 5% - 250 ppm/°C VISHAY R36 4.7 KΩ 0805 SMD standard film res. - 1/8 W - 5% - 250 ppm/°C VISHAY R37 6.8 KΩ 1206 SMD standard film res. - 1/4 W - 5% - 250 ppm/°C VISHAY R38 2.2 MΩ 0805 SMD standard film res. - 1/8 W - 5% - 250 ppm/°C VISHAY R39 51 Ω 0805 SMD standard film res. - 1/8 W - 5% - 250 ppm/°C VISHAY R4 1.2 MΩ 1206 SMD standard film res. - 1/4 W - 1% - 100 ppm/°C VISHAY R41 4.7 KΩ 1206 SMD standard film res. - 1/4 W - 5% - 250 ppm/°C VISHAY R42 10 KΩ 0805 SMD standard film res. - 1/8 W - 1% - 100 ppm/°C VISHAY R43 10 KΩ 1206 SMD standard film res. - 1/4 W - 5% - 250 ppm/°C VISHAY R44 N. M. 0805 Not mounted R45 220 KΩ 1206 SMD standard film res. - 1/4 W - 5% - 250 ppm/°C VISHAY R46 51 Ω 1206 SMD standard film res. - 1/4 W - 5% - 250 ppm/°C VISHAY R47 220 KΩ 1206 SMD standard film res. - 1/4 W - 5% - 250 ppm/°C VISHAY R49 0Ω 0805 SMD standard film res. - 1/8 W - 5% - 250 ppm/°C VISHAY R5 120 KΩ 1206 SMD standard film res. - 1/4 W - 5% - 250 ppm/°C VISHAY R50 10 KΩ 0805 SMD standard film res. - 1/8 W - 5% - 250 ppm/°C VISHAY R51 N. M. 0805 Not mounted R52 10 Ω 0805 SMD standard film res. - 1/8 W - 5% - 250 ppm/°C VISHAY R53 100 Ω 1206 SMD standard film res. - 1/4 W - 5% - 250 ppm/°C VISHAY R54 2.2 KΩ 0805 SMD standard film res. - 1/8 W - 5% - 250 ppm/°C VISHAY R55 470 Ω 0805 SMD standard film res. - 1/8 W - 5% - 250 ppm/°C VISHAY R56 N. M. 0805 Not mounted Doc ID 16774 Rev 2 23/30 Bill of material Table 4. AN3105 EVL130W-SL-EU demonstration board: bill of material (continued) Des. Part type/ part value Case style/ package Description Supplier R57 100 Ω 0805 SMD standard film res. - 1/8 W - 5% - 250 ppm/°C VISHAY R58 150 KΩ 0805 SMD standard film res. - 1/8 W - 1% - 100 ppm/°C VISHAY R59 1.5 Ω 1206 SMD standard film res. - 1/4 W - 5% - 250 ppm/°C VISHAY R6 1.0 MΩ 1206 SMD standard film res. - 1/4 W - 1% - 100 ppm/°C VISHAY R60 8.2 KΩ 0805 SMD standard film res. - 1/8 W - 1% - 100 ppm/°C VISHAY R61 N. M. 1206 Not mounted R62 100 KΩ 0805 SMD standard film res. - 1/8 W - 5% - 250 ppm/°C VISHAY R7 2.0 MΩ 1206 SMD standard film res. - 1/4 W - 5% - 250 ppm/°C VISHAY R8 120 KΩ 1206 SMD standard film res. - 1/4 W - 5% - 250 ppm/°C VISHAY R9 1.5 MΩ 1206 SMD standard film res. - 1/4 W - 1% - 100 ppm/°C VISHAY RV1 300 VAC dia. 15 x 5 p. 7.5 mm 300 V metal oxide varistor - B72214S0301K101 EPCOS RX1 0Ω 1206 SMD standard film res. - 1/4 W - 5% - 250 ppm/°C VISHAY RX2 0Ω 1206 SMD standard film res. - 1/4 W - 5% - 250 ppm/°C VISHAY T1 1860.0013 DWG - ETD34 Resonant power transformer MAGNETICA U1 L6562ATD SO-8 TM PFC controller STMicroelectronics U2 L6599ATD SO-16 Improved HV resonant controller STMicroelectronics U3 SFH617A2X009 SMD4 - 10.16 MM Optocoupler VISHAY U4 SEA05 - N. M. SOT-23-6L CC/CV controller – not mounted STMicroelectronics U5 TS2431AILT SOT-23 Programmable shunt voltage reference STMicroelectronics Z1 PCB REV. 0.2 24/30 Doc ID 16774 Rev 2 AN3105 7 PFC coil specifications PFC coil specifications General description and characteristics ● Application type: consumer, home appliance ● Transformer type: open ● Coil former: vertical type, 6 + 6 pins ● Max. temp. rise: 45 °C ● Max. operating ambient temperature: 60 °C ● Mains insulation: N. A. ● Unit finishing: varnished Electrical characteristics ● Converter topology: boost, transition mode ● Core type: PQ26/20-PC44 or equivalent ● Min. operating frequency: 40 kHz ● Typical operating frequency: 120 kHz ● Primary inductance: 1 mH ± 10% at 1 kHz-0.25 V(a) ● Peak primary current: 2.1 Apk ● RMS primary current: 0.85 ARMS Electrical diagram and winding characteristics Figure 17. PFC coil electrical diagram !- a. Measured between pins #5 and #9. Doc ID 16774 Rev 2 25/30 PFC coil specifications Table 5. AN3105 PFC coil winding data Pins Windings Number of turns Wire type 11 - 3 Aux. 7 0.28 mm - G2 5-9 Primary 71 Multistrand #6 x 0.20 mm - G2 ● Primary winding external insulation: 2 layers of polyester tape. ● Aux. winding is wound on top of primary winding. ● External insulation: 2 layers of polyester tape ● Wire connected to pin 5 is insulated by sleeve. Mechanical aspect and pin numbering ● Maximum height from PCB: 22 mm ● Coil former type: vertical, 6+6 pins (pins #1, 2, 4, 6, 7, 10, and 12 are removed) ● Pin distance: 3.81 mm ● Row distance: 25 mm ● Coil former P/N: TDK BPQ26/20-1112CP ● External copper shield: Not insulated, wound around the ferrite core and including the coil former. Height is 8 mm. Connected to pin #3 by a soldered solid wire. Figure 18. PFC coil mechanical aspect(1) MAX MAX MAX "OTTOMVIEW0).SIDE 1. Dimensions are in millimeters, drawing is not to scale. Manufacturer 26/30 ● MAGNETICA, R. Volpini - Italy (www.magneticait.it) ● Inductor P/N: 1974.0001. Doc ID 16774 Rev 2 !- AN3105 8 Transformer specification Transformer specification General description and characteristics ● Application type: consumer, home appliance ● Transformer type: open ● Coil former: horizontal type, 7 + 7 pins, two slots ● Max. temp. rise: 45 °C ● Max. operating ambient temperature: 60 °C ● Mains insulation: acc. With EN60950 Electrical characteristics ● Converter topology: half-bridge, resonant ● Core type: ETD34-PC44 or equivalent ● Min. operating frequency: 70 kHz ● Typical operating frequency: 100 kHz ● Primary inductance: 770 µH ± 15% at 1 kHz - 0.25 V(b) ● Leakage inductance: 170 µH at 100 kHz - 0.25 V(c) Electrical diagram and winding characteristics Figure 19. Transformer electrical diagram 02)- 3%#! !58 3%#" !- b. Measured between pins 2-4. c. Measured between pins 2-4 with only one secondary winding shorted. The difference between the two measured leakage inductances must be < 10%. Doc ID 16774 Rev 2 27/30 Transformer specification Table 6. Transformer winding data Pins Winding RMS current Number of turns Wire type 2-4 Primary 8-10 12-14 6-7 1. AN3105 1 ARMS 47 #30 x 0.1 mm - G2 SEC - A(1) 0.05 ARMS 9 #60 x 0.1 mm - G2 SEC - B4(1) 2.2 ARMS 9 #60 x 0.1 mm - G2 2.2 ARMS 3 0.28 mm - G2 Aux. (2) Secondary windings A and B must be wound in parallel. 2. Aux. winding is wound on top of primary winding, turns are close to each other, placed on external side of the coil former. Mechanical aspect and pin numbering ● Maximum height from PCB: 30 mm ● Coil former type: horizontal, 7 + 7 pins (pins #1, #3 and #5 removed for PCB reference) ● Pin distance: 5.08 mm ● Row distance: 25.4 mm. Figure 20. Transformer overall drawing MAX MAX MIN MAX ,!"%, -ISSINGPINAND AS0#"REFERENCE 0INSIDEVIEW !- 1. Quotes are in millimeters, drawing is not to scale. Manufacturer 28/30 ● MAGNETICA, R. Volpini - Italy (www.magneticait.it) ● Transformer P/N: 1860.0013. Doc ID 16774 Rev 2 AN3105 9 Revision history Revision history Table 7. Document revision history Date Revision Changes 01-Mar-2010 1 Initial release. 28-Sep-2012 2 – Modified:Table 4 – Modified:Figure 2 – Minor text changes to improve readability Doc ID 16774 Rev 2 29/30 AN3105 Please Read Carefully: Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. All ST products are sold pursuant to ST’s terms and conditions of sale. Purchasers are solely responsible for the choice, selection and use of the ST products and services described herein, and ST assumes no liability whatsoever relating to the choice, selection or use of the ST products and services described herein. No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted under this document. 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The ST logo is a registered trademark of STMicroelectronics. All other names are the property of their respective owners. © 2012 STMicroelectronics - All rights reserved STMicroelectronics group of companies Australia - Belgium - Brazil - Canada - China - Czech Republic - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan Malaysia - Malta - Morocco - Philippines - Singapore - Spain - Sweden - Switzerland - United Kingdom - United States of America www.st.com 30/30 Doc ID 16774 Rev 2