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UM0727User manualIVESTEVAL-ISA018V1 demonstration board based on resonanthalf-bridge SMPS for industrial applicationsIntroductionNACTThis user manual describes a high efficiency solution for industrial power supplies with acontinuous output power of 150 W and peak power up to 240 W. It takes advantage of theresonant approach to minimize switching losses, resulting in higher than 90% efficiency. Thetopology is based on half-bridge and operated in a resonant fashion by means of a resonantLC tank, driven by the L6599 dedicated controller.-IThe board provides one regulated output, VO 24 V with IO 6 A, and an overload capabilityof up to IO 10 A. Output voltage and current are controlled by the TSM1011 constantvoltage and constant current controller, providing square output regulation, while theoverload is managed by thermal protection (PTC) on the output rectifiers.STEVAL-ISA018V1 board prototypeINACTIVE-INACTIVFigure 1.EThe board, shown in Figure 1, is obtainable using the order code STEVAL-ISA018V1.May 2010Doc ID 15906 Rev 11/18www.st.com

ContentsUM0727ContentsDemonstration board description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42Experimental waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123EMI measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17INACTIVE-INACTIVE-INACTIVE12/18Doc ID 15906 Rev 1

UM0727List of figuresList of figuresFigure 8.Figure 9.Figure 10.IVEINACTIVE-INACTIVEFigure 11.Figure 12.NACTFigure 7.STEVAL-ISA018V1 board prototype . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Resonant transformer: pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Resonant transformer: mechanical drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7STEVAL-ISA018V1 board layout with tracks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Midpoint voltage and transformer current - Vin 230 Vac, Vout 24.6 V,Iout 2 A (CH1: HB midpoint voltage; CH2: transformer current) . . . . . . . . . . . . . . . . . . . 12Midpoint voltage and transformer current - Vin 230 Vac, Vout 24.6 V,Iout 2 A (CH1: HB midpoint voltage; CH2: transformer current) . . . . . . . . . . . . . . . . . . . 12Midpoint voltage and transformer current - Vin 230 Vac, Vout 24.6 V,Iout 2 A (CH1: HB midpoint voltage; CH2: transformer current) . . . . . . . . . . . . . . . . . . . 13Midpoint voltage and transformer current - Vin 230 Vac, Vout 24.6 V,Iout 2 A (CH1: HB midpoint voltage; CH2: transformer current) . . . . . . . . . . . . . . . . . . . 13Midpoint voltage and transformer current - Vin 230 Vac, Vout 24.6 V,Iout 2 A (CH1: HB midpoint voltage; CH2: transformer current) . . . . . . . . . . . . . . . . . . . 14Conducted emissions - phase - Vin 230 Vac, Iout 6 A . . . . . . . . . . . . . . . . . . . . . . . . . 15Conducted emissions - neutral - Vin 230 Vac, Iout 6 A . . . . . . . . . . . . . . . . . . . . . . . . 15-IFigure 1.Figure 2.Figure 3.Figure 4.Figure 5.Figure 6.Doc ID 15906 Rev 13/18

Demonstration board description1UM0727Demonstration board descriptionIVEThe STEVAL-ISA018V1 board is based on an LLC resonant converter, and employs the5 Ω, 500 V STF21NM50N power MOSFET as the primary switches in the half-bridge. TheSTF21NM50N is produced using STMicroelectronics’ proprietary high voltage MDmesh IItechnology. Thanks to this technology, the switch features a very low RDS(on) per area, lowgate charge and high switching performance. The device is available in different packages,i.e. the TO-220, TO-247 and TO-220FH.Table 1.NACTThe demonstration board has been designed based on the specifications listed in Table 1.Main specificationsParameterValueInput voltage rangea. 185 to 265 Vac - b. 85 to 185 Vac (with voltage double)Input frequency range50/60 Hz24 V 2%-IOutput voltageOutput power150 W (240Wpk)EN60950ESafetyEN55014IVEMICTThe electrical schematic of the board is shown in Figure 2. The input section is providedwith a connector for line input and a jumper for voltage double operation for a 110 Vac inputvoltage.-INAThe output voltage is available on the CN3 connector. The converter is controlled by theL6599, a double ended primary controller for resonant half-bridge ZVS (zero voltageswitching). The IC controls the output power, changing the switching frequency andcontrolling the half-bridge with a constant 50% duty cycle by means of a dedicated pin,connected to the output feedback through an optocoupler. Light load conditions aremanaged, with optimized consumption, thanks to burst mode operation. The IC alsoincludes a disable function and two-level over-current protection with programmable delay.TIVEIn order to properly run the half-bridge devices and guarantee high efficiency, the ICfeatures an internal P- channel D-MOS transistor with a typical RDS(on) of 200 mΩ as aswitching element to avoid the use of a bootstrap capacitor.INACDuring normal operation the IC is powered by the auxiliary winding of the transformer via theD9 diode. A discrete linear voltage regulator is connected in order to stabilize the auxiliaryvoltage fluctuations. The circuit consists of Q4, C42, R38, D3, D12, C32 and C33.4/18Doc ID 15906 Rev 1

/,1(&1 Doc ID 15906 Rev 1 X[ 55 5 5 X)& ' Q) Q)( 57 & & Q)& ) 17& 56 9& Q) X)& 5 N5 N' & Q) Q)& TIVE/ ' 4 ' N5 '3 Q)& 05 & .5 5 N5 N5 S)& 5& & Q) ',6 /,1( ,6(1 67% 9* 55 8 3)&B6723 *1' /9* 1 & 5 & 5 5 Q)& Q) Q)& 5 N Q)4 ' 4 E 5 5 5& 55 5 5IV5 5 5 5' 55 ' N N5 & Q)CT 9%2275 .5 N5 N/ 287 5)PLQ &) '(/ &VV X) 9& X) 9NA-I S)-03 9DF&1 9&& 4 7 ' Q)& 5 6736 6 Q& 2378 S) 6736 6' 8 5 55 5& 76 9&& & & 5 N Q& N5 & Q) N & 5 .760 95() 9FF&F 2XW&F *QG&Y &Y 8 N5 X) N5 & Q)& 5 N N& 5 5 N5 5 N .5 N5 N Q) Q)IVE5 N5 Q X) 9& N& & Q5 6 17& N& 95() QNACT& Q)& -I5 5' N5 7'. 65: (& %& 5 N2377 (50 / 3527(&7,21 5 9' 5 Q)& 5 N N& X)' &1 9 Figure 2. INACUM0727Demonstration board descriptionSchematic!- V 5/18

Demonstration board descriptionUM0727Regulation of the output voltage is performed by secondary feedback on the 24 V output.The feedback network consists of a programmable voltage reference, TSM1011, driving anoptocoupler which ensures the required insulation between the primary and secondarysections. The optotransistor drives the feedback pin (RFMIN) which controls the operation ofthe IC.IVEThe resonant transformer is based on a two-slot coil former and an EER39-PC40 ferritecore, manufactured by TDK. The transformer ensures safety insulation in accordance withEN60950.Table 2.Resonant transformer specificationsParameterValueCoreEER39 – PC40Coil former2 slot-IPrimary inductance, LpLeakage inductance, Llk450 µH 10%150 µH 10%32 (0.15x20) – 220 mΩ (DC)Secondary turns, Ns2x7 (0.2x30) (bifilar) – 40 mΩ (DC)8 (on primary winding)CTAuxiliary turns, NauxIVEPrimary turns, NpResonant transformer: pinoutTIVE-INAFigure 3.NACTIn Table 2 the main features of the transformer are listed and in Figure 3 and 4 the pinoutand the geometrical characteristics are shown respectively.INAC!- V 6/18Doc ID 15906 Rev 1

UM0727Demonstration board descriptionFigure 4.Resonant transformer: mechanical drawingNACTIVE !- V IVE-IThe output voltage can be adjusted down to 1.235 V by a voltage divider. An internaloscillator fixes the switching frequency up to 500 kHz to minimize the size of externalcomponents. The power IC features several layers of protection, such as pulse by pulsecurrent limit with internal frequency modulation aimed at an effective constant current shortcircuit protection, feedback disconnection and thermal shutdown. Finally, it can besynchronized using a dedicated pin as well as inhibited for reduced standby powerconsumption and time sequence operations.STEVAL-ISA018V1 board layout with tracksINACTIVE-INAFigure 5.CTThe board layout is shown in Figure 5. The whole power supply is produced on a doubleside 35 µm PCB FR-4 (130 x 66 mm).AM04390v1Doc ID 15906 Rev 17/18

Demonstration board descriptionTable 3.UM0727STEVAL-ISA018V1 BOM listValueDescriptionC1220 nFPolyester X2 – 275 VacC2100 nFPolyester X2 – 275 VacC3680 µFElect. capacitor 200 VC4220 pFCeramic capacitor NPOC5100 nFCeramic capacitor Y5 VC6100 nFCeramic capacitor Y5 VC74.7 nFCeramic capacitor Y5 VC810 nFCeramic capacitor Z5UC947 nFCeramic capacitor Y5 VC10100 pFCeramic capacitor NPOC12470 pFCeramic capacitor Y5 VC14470 pFCeramic capacitor Y5 VC15220 pFPolip. capacitor 630 VC1622 nFCeramic capacitor 630 VC174.7 µFC1847 nFC19100 nFC20470 µFC21470 µFC22470 µFC23470 µFC24220 nFC25100 µFC262.2 nFC2722 nFCeramic capacitor 630 VC28100 nFCeramic capacitor Y5 VC29100 nFCeramic capacitor Y5 VC30100 nFCeramic capacitor Y5 VC32100 µFElect. capacitor 25 VC33100 nFCeramic capacitor Y5 VC3547 nFCeramic capacitor Y5 VC36100 nFCeramic capacitor Y5 VC37680 µFElect. capacitor 200 VC394.7 nFCeramic capacitor Y2 – 250 VacC404.7 nFCeramic capacitor Y2 – 250 VacNACT-IEIVElect. capacitor-INACTElect. capacitor Y5 VTIVEINAC8/18IVEReferenceCeramic capacitor Y5 VElect. capacitor 35 VElect. capacitor 35 VElect. capacitor 35 VElect. capacitor 35 VCeramic capacitor Y5 VElect. capacitor 50 VPolyester capacitor Y1 - 300 VacDoc ID 15906 Rev 1

UM0727STEVAL-ISA018V1 BOM list (continued)ReferenceValueDescriptionC421 µFElect. capacitor 160 VCN13 posConnector - pitch 3.96 mmCN22 posConnector - pitch 3.96 mmCN34 posConnector - pitch 3.96 mmDP1S1M/11TRectifier 1 A - 1000 V - DO214ACNACTD1Bridge rectifier 8 A - 600 VIVETable 3.Demonstration board descriptionD2Zener diode 24 V - 1 WLS4148Ultrafast diode 200 mA - 75 V - SOD80D4LS4148Ultrafast diode 200 mA - 75 V - SOD80D5LS4148Ultrafast diode 200 mA - 75 V - SOD80D6LS4148Ultrafast diode 200 mA - 75 V - SOD80D7LS4148Ultrafast diode 200 mA - 75 V - SOD80D8STPS20H100STMicroelectronics - Schottky rectifier 2x10A - 100 VD9BAV23CFast rectifier 2x400 mA - 250 V - SOT23D11LS4148Ultrafast diode 200 mA - 75 V - SOD80IVE-ID3STPS20H100STMIcroelectronics - Schottky rectifier 2x10 A - 100 VDL1LEDLED red 0805L12x25 mHNTC12Ω-4ANTC210 kΩF13.15 AR1100 kΩR2470 kΩR310 kΩResistor, 5% - SMD 0603R410 kΩResistor, 5% - SMD 0603R51 MΩResistor, 5% - SMD 0603R656 kΩResistor, 5% - SMD 0603R810 ΩResistor, 5% - SMD 060310 ΩResistor, 5% - SMD 0603R10100 ΩResistor, 5% - SMD 0603R1110 ΩResistor, 5% - SMD 0603R12100 ΩResistor, 5% - SMD 0603R13100 ΩResistor, 5% - SMD 1206R14100 ΩResistor, 5% - SMD 0603R9CTD13TIVEZener diode 12 V - 1 WINACD12-INACM choke - TDK HF2836 - 1.2 ANTC Inrush current suppressorNTC -40 C to 125 CFuse 250 V delayedResistor, 5% - SMD 1206Resistor, 5% - SMD 1206Doc ID 15906 Rev 19/18