AN - EVAL IC E2QR22 8 0G - 1 2 0 W 5 V SMPS Eva lua ti on Board wi th Quas i Re s onant C oolSE T™ I C E2 QR2 2 8 0 G - 1 Application Note About this document Scope and purpose This document is an engineering report that describes universal input 20 W 5 V off-line flyback converter using Infineon Quasi-Resonant CoolSET™ ICE2QR2280G-1 which offers high efficiency, very low standby power, wider VCC operating range and various mode of protections for a high reliable system. This evaluation board is designed to evaluate the performance of ICE2QR2280G-1 in ease of use. Intended audience This document is intended for users of the ICE2QR2280G-1 who wish to design low cost, high efficiency Quasi-Resonant off-line SMPS for small power supply such as Blu-ray, DVD player, set-top box, game console, smart meter, charger and auxiliary power of high power system such as LED TV, etc. Table of Contents About this document ................................................................................................................... 1 Table of Contents ........................................................................................................................ 1 1 Abstract ..................................................................................................................... 3 2 Evaluation board ........................................................................................................ 3 3 Specification of evaluation board ................................................................................. 4 4 Features of ICE2QR2280G-1 .......................................................................................... 4 5 5.1 5.2 5.3 5.4 Circuit description....................................................................................................... 4 Mains input rectification and filtering ..................................................................................................... 4 Integrated MOSFET and PWM control ..................................................................................................... 4 Output stage .............................................................................................................................................. 5 Feedback loop ........................................................................................................................................... 5 6 6.1 Circuit operation ......................................................................................................... 5 Startup operation...................................................................................................................................... 5 1 Revision 1.1, 2015-04-02 20 W 5 V SMPS Evaluation Board with Quasi-Resonant CoolSET™ ICE2QR2280G-1 Abstract 6.2 6.3 6.4 6.5 Normal mode operation ........................................................................................................................... 5 Primary side peak current control........................................................................................................... 5 Digital frequency reduction ..................................................................................................................... 5 Burst mode operation............................................................................................................................... 6 7 7.1 7.2 7.3 7.4 7.5 7.6 Protection features ..................................................................................................... 6 VCC over voltage and under voltage protection ...................................................................................... 6 Foldback point protection ....................................................................................................................... 6 Open loop/over load protection .............................................................................................................. 6 Adjustable output overvoltage protection ............................................................................................. 7 Short winding protection ......................................................................................................................... 7 Auto restart for over temperature protection ........................................................................................ 7 8 Circuit diagram ........................................................................................................... 8 9 9.1 9.2 PCB layout ................................................................................................................. 9 Top side ...................................................................................................................................................... 9 Bottom side................................................................................................................................................ 9 10 Component list ......................................................................................................... 10 11 Transformer construction .......................................................................................... 11 12 12.1 12.2 Test results .............................................................................................................. 11 Efficiency, regulations and output ripple .............................................................................................11 Standby power ........................................................................................................................................13 13 References ............................................................................................................... 13 Revision History........................................................................................................................ 13 Application Note 2 Revision 1.1, 2015-04-02 20 W 5 V SMPS Evaluation Board with Quasi-Resonant CoolSET™ ICE2QR2280G-1 Abstract 1 Abstract This application note is a description of 20 W switching mode power supply evaluation board designed in a quasi resonant flyback converter topology using ICE2QR2280G-1 Quasi-resonant CoolSET™ .The target application of ICE2QR2280G-1 are for set-top box, portable game controller, DVD player, netbook adapter and auxiliary power supply for LCD TV, etc. With the CoolMOS™ integrated in this IC, it greatly simplifies the design and layout of the PCB. Due to valley switching, the turn on voltage is reduced and this offers higher conversion efficiency comparing to hard-switching flyback converter. With the DCM mode control, the reverse recovery problem of secondary rectify diode is relieved. And for its natural frequency jittering with line voltage, the EMI performance is better. Infineon’s digital frequency reduction technology enables a quasi-resonant operation till very low load. As a result, the system efficiency, over the entire load range, is significantly improved compared to conventional free running quasi resonant converter implemented with only maximum switching frequency limitation at light load. In addition, numerous adjustable protection functions have been implemented in ICE2QR2280G-1 to protect the system and customize the IC for the chosen application. In case of failure modes, like open control-loop/over load, output overvoltage, and transformer short winding, the device switches into Auto Restart Mode or Latch-off Mode. By means of the cycle-by-cycle peak current limitation plus foldback point correction, the dimension of the transformer and current rating of the secondary diode can both be optimized.Thus, a cost effective solution can be easily achieved. 2 Evaluation board This document contains the list of features, the power supply specification, schematic, bill of material and the transformer construction documentation. Typical operating characteristics such as performance curve and scope waveforms are showed at the rear of the report. Figure 1 EVAL ICE2QR2280G-1 Application Note 3 Revision 1.1, 2015-04-02 20 W 5 V SMPS Evaluation Board with Quasi-Resonant CoolSET™ ICE2QR2280G-1 Specification of evaluation board 3 Table 1 Specification of evaluation board Specification of EVAL ICE2QR2280G-1 Input voltage 85 VAC~265 VAC Input frequency 50~60 Hz Output voltage, current & power 5 V, 4 A, 20 W Minimum switching frequency at full load and minimum input AC voltage 65 kHz No-load power consumption < 50 mW Active mode four point average efficiency (25%,50%,75% & 100%load) >80% at 115 VAC & 230 VAC 4 Features of ICE2QR2280G-1 Table 2 Features of ICE2QR2280G-1 800 V avalanche rugged CoolMOS™ with built-in startup Cell Quasi resonant operation till very low load Active burst mode operation for low standby input power (< 0.1 W) Digital frequency reduction with decreasing load for reduced switching loss Built-in digital soft-start Foldback point correction, cycle-by-cycle peak current limitation and maximum on time limitation Auto restart mode for VCC over-voltage protection, under-voltage protection, over-load protection and overtemperature protection Latch-off mode for adjustable output over-voltage protection and transformer short-winding protection Lower VCC turn off threshold 5 Circuit description 5.1 Mains input rectification and filtering The AC line input side comprises the input fuse F1 as overcurrent protection. The X2 Capacitors C1 and Choke L1 form a main filter to minimize the feedback of RFI into the main supply. After the bridge rectifier BR1, together with a smoothing capacitor C2, provide a voltage of 70 VDC to 380 VDC depending on mains input voltage. 5.2 Integrated MOSFET and PWM control ICE2QR2280G-1 is comprised of a power MOSFET and the Quasi-Resonant controller; this integrated solution greatly simplifies the circuit layout and reduces the cost of PCB manufacturing. The PWM switch-on is determined by the zero-crossing input signal and the value of the up/down counter. The PWM switch-off is determined by the feedback signal VFB and the current sensing signal VCS. ICE2QR2280G-1 also performs all necessary protection functions in flyback converters. Details about the information mentioned above are illustrated in the product datasheet. Application Note 4 Revision 1.1, 2015-04-02 20 W 5 V SMPS Evaluation Board with Quasi-Resonant CoolSET™ ICE2QR2280G-1 Circuit operation 5.3 Output stage On the secondary side, 5 V output, the power is coupled out via a schottky diode D21. The capacitors C21 and C22 provide energy buffering followed by the L-C filters L21 and C23 to reduce the output ripple and prevent interference between SMPS switching frequency and line frequency considerably. Storage capacitors C21 and C22 are designed to have an internal resistance (ESR) as small as possible. This is to minimize the output voltage ripple caused by the triangular current. 5.4 Feedback loop For feedback, the output is sensed by the voltage divider of Rc1 and Rc3 and compared to TL431 internal reference voltage. Cc1, Cc2 and Rc4 comprise the compensation network. The output voltage of TL431 is converted to the current signal via optocoupler IC2 and two resistors Rc5 and Rc6 for regulation control. 6 Circuit operation 6.1 Startup operation Since there is a built-in startup cell in the ICE2QR2280G-1, there is no need for external start up resistor, which can improve standby performance significantly. When VCC reaches the turn on voltage threshold 18V, the IC begins with a soft start. The soft-start implemented in ICE2QR2280G-1 is a digital time-based function. The preset soft-start time is 12ms with 4 steps. If not limited by other functions, the peak voltageon CS pin will increase step by step from 0.32V to 1V finally. After IC turns on, the VCC voltage is supplied by auxiliary windings of the transformer. 6.2 Normal mode operation The secondary output voltage is built up after startup. The secondary regulation control is adopted with TL431 and optocoupler. The compensation network Cc1, Cc2 and Rc4 constitute the external circuitry of the error amplifier of TL431. This circuitry allows the feedback to be precisely controlled with respect to dynamically varying load conditions, therefore providing stable control. 6.3 Primary side peak current control The MOSFET drain source current is sensed via external resistor R4 and R4A. Since ICE2QR2280G-1 is a current mode controller, it would have a cycle-by-cycle primary current and feedback voltage control which can make sure the maximum power of the converter is controlled in every switching cycle. 6.4 Digital frequency reduction During normal operation, the switching frequency for ICE2QR2280G-1 is digitally reduced with decreasing load. At light load, the MOSFET will be turned on not at the first minimum drain-source voltage time, but on the nth. The counter is in range of 1 to 7, which depends on feedback voltage in a time-base. The feedback voltage decreases when the output power requirement decreases, and vice versa. Therefore, the counter is set by monitoring voltage VFB. The counter will be increased with low VFB and decreased with high VFB. The thresholds are preset inside the IC. Application Note 5 Revision 1.1, 2015-04-02 20 W 5 V SMPS Evaluation Board with Quasi-Resonant CoolSET™ ICE2QR2280G-1 Protection features 6.5 Burst mode operation At light load condition, the SMPS enters into Active Burst Mode. At this stage, the controller is always active but the VCC must be kept above the switch off threshold. During active burst mode, the efficiency increase significantly and at the same time it supports low ripple on Vout and fast response on load jump. For determination of entering Active Burst Mode operation, three conditions apply: 1. the feedback voltage is lower than the threshold of VFBEB(1.25 V). Accordingly, the peak current sense voltage across the shunt resistor is 0.18; 2. the up/down counter is 7; 3. and a certain blanking time (tBEB). Once all of these conditions are fulfilled, the Active Burst Mode flip-flop is set and the controller enters Active Burst Mode operation. This multi-condition determination for entering Active Burst Mode operation prevents mistriggering of entering Active Burst Mode operation, so that the controller enters Active Burst Mode operation only when the output power is really low during the preset blanking time. During active burst mode, the maximum current sense voltage is reduced from 1 V to 0.34 V so as to reduce the conduction loss and the audible noise. At the burst mode, the FB voltage is changing like a sawtooth between 3.0 and 3.6 V. The feedback voltage immediately increases if there is a high load jump. This is observed by one comparator. As the current limit is 34% during Active Burst Mode a certain load is needed so that feedback voltage can exceed VFBLB (4.5 V). After leaving active busrt mode, maximum current can now be provided to stabilize VO. In addition, the up/down counter will be set to 1 immediately after leaving Active Burst Mode. This is helpful to decrease the output voltage undershoot. 7 Protection features 7.1 VCC over voltage and under voltage protection During normal operation, the VCC voltage is continuously monitored. When the VCC voltage falls below the under voltage lock out level (VCC,off) or the VCC voltage increases up to VCC,OVP, the IC will enter into autorestart mode. 7.2 Foldback point protection For a quasi-resonant flyback converter, the maximum possible output power is increased when a constant current limit value is used for all the mains input voltage range. This is usually not desired as this will increase additional cost on transformer and output diode in case of output over power conditions. The internal fold back protection is implemented to adjust the V CS voltage limit according to the bus voltage. Here, the input line voltage is sensed using the current flowing out of ZC pin, during the MOSFET on-time. As the result, the maximum current limit will be lower at high input voltage and the maximum output power can be well limited versus the input voltage. 7.3 Open loop/over load protection In case of open control loop, feedback voltage is pulled up with internally block. After a fixed blanking time 30 ms, the IC enters into auto restart mode. In case of secondary short-circuit or overload, regulation voltage VFB will also be pulled up, same protection is applied and IC will auto restart. Application Note 6 Revision 1.1, 2015-04-02 20 W 5 V SMPS Evaluation Board with Quasi-Resonant CoolSET™ ICE2QR2280G-1 Protection features 7.4 Adjustable output overvoltage protection During off-time of the power switch, the voltage at the zero-crossing pin ZC is monitored for output overvoltage detection. If the voltage is higher than the preset threshold 3.7 V for a preset period 100 μs, the IC is latched off. 7.5 Short winding protection The source current of the MOSFET is sensed via two shunt resistors R4 and R4A in parallel. If the voltage at the current sensing pin is higher than the preset threshold V CSSW of 1.68 V during the on-time of the power switch, the IC is latched off. This constitutes a short winding protection. To avoid an accidental latch off, a spike blanking time of 190 ns is integrated in the output of internal comparator. 7.6 Auto restart for over temperature protection The IC has a built-in over temperature protection function. When the controller’s temperature reaches 140 °C, the IC will shut down switch and enters into autorestart. This can protect power MOSFET from overheated. Application Note 7 Revision 1.1, 2015-04-02 20 W 5 V SMPS Evaluation Board with Quasi-Resonant CoolSET™ ICE2QR2280G-1 Circuit diagram 8 Circuit diagram Figure 2 Schematic of EVAL ICE2QR2280G-1 Application Note 8 Revision 1.1, 2015-04-02 20 W 5 V SMPS Evaluation Board with Quasi-Resonant CoolSET™ ICE2QR2280G-1 PCB layout 9 PCB layout 9.1 Top side Figure 3 Top side component legend 9.2 Bottom side Figure 4 Bottom side copper and component legend Application Note 9 Revision 1.1, 2015-04-02 20 W 5 V SMPS Evaluation Board with Quasi-Resonant CoolSET™ ICE2QR2280G-1 Component list 10 Component list Table 3 Bill of materials No. Designator Description 1 BR1 2KBB80R 2 F1 1.6A/250Vac 3 L21 1.5uH 4 R2 2R, SMD 5 R3 32.4k, SMD 6 R4 1.5R 7 R4A 4.7R, SMD 8 R5 4.64k, SMD 9 Rc1 10k, SMD 10 Rc3 10k, SMD 11 Rc4 2.7k 12 Rc5 1K 13 Rc6 68R 14 C1 0.1uF/275V B32922X2MKP/2H Epcos 15 C2 68uF/400V B43501A9686M Epcos 16 C4 1nF/250V,Y1 17 C5 33uF/50V B41821 Epcos 18 C6 0.1uF, SMD 19 C7 100pF 20 C8 1nF 21 C21 2200uF/16V 22 C22 2200uF/16V 23 Cc1 0.1uF 24 Cc2 1nF 25 C23 220uF/25V 26 EMI 2 x 27mH, 0.9A B82732R2901B30 Epcos 27 TR1 1504uH 28 IC2 SFH617A-3 29 IC3 TL431 30 D1 UF4005 UF4005 Vishay 31 D2 1N4148 32 ZD1 22V zener diode 33 ZD2 Zener diode 34 D21 STPS30L45T Application Note Part Number Manufacturer P6KE200A 10 Revision 1.1, 2015-04-02 20 W 5 V SMPS Evaluation Board with Quasi-Resonant CoolSET™ ICE2QR2280G-1 Transformer construction 11 Transformer construction Core and material: EPCOS(N87)or TDK PC44 EF25/13/7 Bobbin: Vertical version Primary Inductance, Lp=1504 μH( ±10%), measured between pin 4 and pin 5 Start 1 3 7 Stop 2 5 9 No. of turns 12 48 4 Wire size 1XAWG#32 1XAWG#28 3XAWG#25 Layer Auxiliary 1 /2 Primary Secondary 6 4 8 3 4 48 3XAWG#25 1XAWG#28 Secondary 1 /2 Primary Figure 5 Transformer structure 12 Test results 12.1 Efficiency, regulations and output ripple Table 4 Vin (VAC) 85 115 230 265 Efficiency, regulation & output ripple Pin (W) Vout (VDC) Iout (A) Pout (W) Efficiency (%) 0.0207 4.97 0.00 2.4000 4.97 0.40 1.99 82.83 6.1700 12.4500 4.97 1.00 4.97 80.49 4.97 2.00 9.93 79.76 18.9300 4.96 3.00 14.89 78.67 26.0300 4.96 4.00 19.85 76.27 0.0260 4.97 0.00 2.4900 4.97 0.40 1.99 79.84 6.1300 4.97 1.00 4.97 81.01 12.3000 4.97 2.00 9.93 80.73 18.4900 4.96 3.00 14.89 80.54 25.1000 4.96 4.00 19.85 79.09 0.0264 4.97 0.00 2.5700 4.97 0.40 1.99 77.35 6.2500 4.97 1.00 4.97 79.46 12.3000 4.97 2.00 9.93 80.73 18.3500 4.96 3.00 14.89 81.16 24.4300 4.96 4.00 19.85 81.26 0.0308 4.97 0.00 2.5800 4.97 0.40 1.99 77.05 6.3200 4.97 1.00 4.97 78.58 12.3600 4.97 2.00 9.93 80.34 18.4300 4.96 3.00 14.89 80.80 24.5000 4.96 4.00 19.85 81.03 Application Note 11 Average Efficiency (%) 78.79 80.34 80.65 80.19 Revision 1.1, 2015-04-02 20 W 5 V SMPS Evaluation Board with Quasi-Resonant CoolSET™ ICE2QR2280G-1 Test results Figure 6 Efficiency vs AC line input voltage Figure 7 Efficiency vs output power @ 115 VAC and 230 VAC line Application Note 12 Revision 1.1, 2015-04-02 20 W 5 V SMPS Evaluation Board with Quasi-Resonant CoolSET™ ICE2QR2280G-1 References 12.2 Standby power Figure 8 Standby power vs AC line input voltage (measured by Yokogawa WT210 power meter integration mode) 13 References [1] ICE2QR2280G-1 data sheet, Infineon Technologies AG [2] ICE2QRxx65/80x Quasi- Resonant CoolSET™ Design Guide. [ANPS0053] Revision History Major changes since the last revision Page or Reference Description of change -- Name change to EVAL Application Note 13 Revision 1.1, 2015-04-02 Trademarks of Infineon Technologies AG AURIX™, C166™, CanPAK™, CIPOS™, CIPURSE™, CoolMOS™, CoolSET™, CORECONTROL™, CROSSAVE™, DAVE™, DI-POL™, EasyPIM™, EconoBRIDGE™, EconoDUAL™, EconoPIM™, EconoPACK™, EiceDRIVER™, eupec™, FCOS™, HITFET™, HybridPACK™, I²RF™, ISOFACE™, IsoPACK™, MIPAQ™, ModSTACK™, my-d™, NovalithIC™, OptiMOS™, ORIGA™, POWERCODE™, PRIMARION™, PrimePACK™, PrimeSTACK™, PRO-SIL™, PROFET™, RASIC™, ReverSave™, SatRIC™, SIEGET™, SINDRION™, SIPMOS™, SmartLEWIS™, SOLID FLASH™, TEMPFET™, thinQ!™, TRENCHSTOP™, TriCore™. Other Trademarks Advance Design System™ (ADS) of Agilent Technologies, AMBA™, ARM™, MULTI-ICE™, KEIL™, PRIMECELL™, REALVIEW™, THUMB™, µVision™ of ARM Limited, UK. AUTOSAR™ is licensed by AUTOSAR development partnership. Bluetooth™ of Bluetooth SIG Inc. CAT-iq™ of DECT Forum. COLOSSUS™, FirstGPS™ of Trimble Navigation Ltd. EMV™ of EMVCo, LLC (Visa Holdings Inc.). EPCOS™ of Epcos AG. FLEXGO™ of Microsoft Corporation. FlexRay™ is licensed by FlexRay Consortium. HYPERTERMINAL™ of Hilgraeve Incorporated. IEC™ of Commission Electrotechnique Internationale. IrDA™ of Infrared Data Association Corporation. ISO™ of INTERNATIONAL ORGANIZATION FOR STANDARDIZATION. MATLAB™ of MathWorks, Inc. MAXIM™ of Ma xim Integrated Products, Inc. MICROTEC™, NUCLEUS™ of Mentor Graphics Corporation. MIPI™ of MIPI Alliance, Inc. MIPS™ of MIPS Technologies, I nc., USA. muRata™ of MURATA MANUFACTURING CO., MICROWAVE OFFICE™ (MWO) of Applied Wave Research Inc., OmniVision™ of OmniVision Technologies, Inc. Openwave™ Openwave Systems Inc. RED HAT™ Red Hat, Inc. RFMD™ RF Micro Devices, Inc. SIRIUS™ of Sirius Satellite Radio Inc. SOLARIS™ of Sun Microsystems, Inc. SPANSION™ of Spansion LLC Ltd. Symbian™ of Symbian Software Limited. TAIYO YUDEN™ of Taiyo Yuden Co. TEAKLITE™ of CEVA, Inc. TEKTRONIX™ of Tektronix Inc. TOKO™ of TOKO KABUSHIKI KAISHA TA. UNIX™ of X/Open Company Limited. VERILOG™, PALLADIUM™ of Cade nce Design Systems, Inc. VLYNQ™ of Texas Instruments Incorporated. VXWORKS™, WIND RIVER™ of WIND RIVER SYSTEMS, INC. ZETEX™ of Diodes Zetex Limited. Last Trademarks Update 2011-11-11 www.infineon.com Edition 2015-04-02 Published by Infineon Technologies AG 81726 Munich, Germany © 2015 Infineon Technologies AG. All Rights Reserved. Do you have a question about any aspect of this document? Email: [email protected] Document reference ANEVAL_201501_PL21_007 Legal Disclaimer THE INFORMATION GIVEN IN THIS APPLICATION NOTE (INCLUDING BUT NOT LIMITED TO CONTENTS OF REFERENCED WEBSITES) IS GIVEN AS A HINT FOR THE IMPLEMENTATION OF THE INFINEON TECHNOLOGIES COMPONENT ONLY AND SHALL NOT BE REGARDED AS ANY DESCRIPTION OR WARRANTY OF A CERTAIN FUNCTIONALITY, CONDITION OR QUALITY OF THE INFINEON TECHNOLOGIES COMPONENT. THE RECIPIENT OF THIS APPLICATION NOTE MUST VERIFY ANY FUNCTION DESCRIBED HEREIN IN THE REAL APPLICATION. INFINEON TECHNOLOGIES HEREBY DISCLAIMS ANY AND ALL WARRANTIES AND LIABILITIES OF ANY KIND (INCLUDING WITHOUT LIMITATION WARRANTIES OF NONINFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS OF ANY THIRD PARTY) WITH RESPECT TO ANY AND ALL INFORMATION GIVEN IN THIS APPLICATION NOTE. Information For further information on technology, delivery terms and conditions and prices, please contact the nearest Infineon Technologies Office (www.infineon.com). Warnings Due to technical requirements, components may contain dangerous substances. For information on the types in question, please contact the nearest Infineon Technologies Office. Infineon Technologies components may be used in life-support devices or systems only with the express written approval of Infineon Technologies, if a failure of such components can reasonably be expected to cause the failure of that life-support device or system or to affect the safety or effectiveness of that device or system. Life support devices or systems are intended to be implanted in the human body or to support and/or maintain and sustain and/or protect human life. If they fail, it is reasonable to assume that the health of the user or other persons may be endangered.