AN-FEB_FAN6224 - Fairchild Semiconductor
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1. A PAD4 connects to A B PADS connects to B C PADI connects to C For low side application R 3 is 0 Q to short the AUX and Vpp terminal D Short c Vin Ny N2 A Vour e e AZ al Ne 2 Cut off B A Figure 6 Low Side Application R R 47R 1206 B 5 PADI ca C 1w1206 GND R 270K 1206 8 7 5 PADI PADI Figure 7 Daughter Card Schematic 2013 Fairchild Semiconductor Corporation 11 FEBFAN6224M_CP01 lt Rev 1 0 2 E FAIRCHILD gt aaa Watt ei A SEMICONDUCTOR 1 7 Modification of Power Stage for High Side Rectification Figure 8 shows the flyback system for high side application To mount the daughter card on the high side cut the connection of transformer terminal A and output terminal B Figure 9 shows the daughter card schematic The components of the daughter card include a SR MOSFET 100 V 8 5 mQ the SR controller FAN6224 and detection circuits The connection method is A PADS connects to A B PAD4 connects to B C PADI connects to C D PAD2 connects to D For high side application R 3 is open c A A Figure 8 High Side Application RI2 R 47R 1206 c4 C iw1206 GND PADI PADI Figure 9 Daughter Card Schematic 2013 Fairchild Semiconductor Corporation 12 FEBFAN6224M_CP01 lt Rev 1 0 22. sell FAIRCHILD ee SEMICONDUCTOR 2 Photographs ww fairchildsemi com INO Kama sas FAIRCHILD mem SENI CONDUC TOR PLMNO255 REV 0 Figure 10 Top View Bottom View Figure 11 2013 Fairchild Semiconductor Corporation 13 FEBFAN6224M_CP01 lt Rev 1 0 2 EET FAIRCHILD SEMICONDUCTOR 3 Schematic C4 BI C 1n 1206 R 47R 1206 DET N ww fairchildsemi com R12 R 47R 1206 xD OM PADI D e Q 3 I NY Ql PADI GATE FDPO8SN10A wanes L PADI R7 DI IN4148 RVR 1306 vr ee Cl RI C 10n 1206 2 R 120K 12063 ERA R 27K 1206 CNI R2 R 88 7K 0805 GND DET GATE AUX VDD O AUX VDD VDD AUX CONS e PADI PADI Figure 12 Schematic 14 FEBFAN6224M_CP01 lt Rev 1 0 2 2013 Fairchild Semiconductor Corporation garapan FAIRCHILD SEMICONDUCTOR ww fairohilds mi com 4 Printed Circuit Board cno EE FAIRCHILD ISEMICONDUCTO ii 5 REV 0 Figure 13 Top Overlayer Figure 14 Bottom Layer EE Figure 15 Bottom Overlayer 2013 Fairchild Semiconductor Corporation 15 FEBFAN6224M_CP01 lt Rev 1 0 2 Se FAIRCHILD SEMICONDUCTOR 5 Bill of Materials ww fairchildsemi com Part Number Manufacturer Description Quantity ID 02 5300005 00 SMD Resistor 1206 0 Q 5 REEL 3 R3 R7 R8 02 5347005 00 SMD Resistor 1206 47 Q
3. 9 is not satisfied some of the parameters need to be redesigned Step 2 Calculate the Auxiliary Winding Ng N Von N j Vour 1 0 Step 3 Select the Capacitance of Crp For low frequency systems under 100 kHz Crp is recommended as 10 nF for high frequency systems from 100 kHz to 140 kHz Crp is recommended as 1 nF Step 4 Calculate the Operating Range of Ratio pc The maximum of Ratio pc is Vian Vo 1 1 54 Ratio po lt 11 The minimum of Ratio pc is Wa ua Var 1 4 8 Ratio gt 12 Step 5 Calculate the Resistance of R Choose R to be equal to 12 KQ and Ratiorpc to be close to its maximum value R is obtained as below R R Ratio pc 1 13 Step 6 Calculate Ratiores Choose K to be in the range of 4 to 4 5 The dead time is larger when K is larger and vice versa RatiOggs is calculated as below Ratiouec n K 14 2 Ratiores 2013 Fairchild Semiconductor Corporation 7 FEBFAN6224M_CP01 lt Rev 1 0 2 Se FAIRCHILD eS eee SEMICONDUCTOR ww fairchildsemi com Verify Ratioggs satisfies lt Vor lt 4 8 Ratiopes M 15 If 15 is not satisfied select another proper Ratiorgs Calculate Ratiorpc by 14 and verify that Ratio ec satisfies 11 and 12 If 11 and 12 cannot be satisfied some of the system parameters such as nj Vinmax Vinmin and Nour need to be redesigned Step 7 Calculate the Resistance of R3 Cho
4. V IN MAX Vour 1 Ratio 5 gt 4 8 Step 4 Calculate the Resistance of R Choose R to be equal to several tens kilo ohms and Ratio Pc to be close to its maximum value R is obtained as below R R Ratio po 1 5 Step 5 Calculate Ratiokes Choose K to be in the range of 4 to 4 5 The dead time is larger when K is larger and vice versa RatiOggs is calculated as below Ratio ec Ratiores Kk 6 Verify that Ratioggs satisfies Vol Ag RatiOnes 7 If 7 is not satisfied select another proper Ratioggs Calculate Ratio pc by 6 and verify Ratioypc satisfies 3 and 4 If 3 and 4 cannot be satisfied some of the system parameters such as nj Vmax Vinmin and Nour need to be redesigned Step 6 Calculate the Resistance of R Choose Ry to be equal to several tens kilo ohms and the Ratioggs is based on the calculated result of 6 and 7 R3 is obtained as below R R Ratioge 1 8 2013 Fairchild Semiconductor Corporation 6 FEBFAN6224M_CP01 lt Rev 1 0 2 Se FAIRCHILD EEN SEMICONDUCTOR ww fairchildsemi om Flyback High Side Rectification Refer to the typical application circuit in Figure 2 for the following design procedure Step 1 Confirm the Applicability of FAN6224 If the system parameters nj Vinmax Vino and Nour satisfy Vy MIN V 4 V IN MAX at V n OUT n OUT 9 gt 1 54 4 8 FAN6224 is applicable for this system If
5. Typical Application Circuit for Low Side Flyback Converter Figure 2 Typical Application Circuit for High Side Flyback Converter 2013 Fairchild Semiconductor Corporation 3 FEBFAN6224M_CP01 lt Rev 1 0 2 Se FAIRCHILD a ee SEMICONDUCTOR ww fairchildsemi com 1 1 Introduction of Linear Predict Timing Control The SR MOSFET turn off timing is determined by linear predict timing control The operation principle is based on the volt second balance theorem which states the inductor average voltage is zero during a switching period in steady state so the charge voltage and charge time product is equal to the discharge voltage and discharge time product In flyback converters the charge voltage on the magnetizing inductor is input voltage Vm while the discharge voltage is the reflected output voltage nVoyr The following equation can be drawn V tmon N Vour Los 1 where tpyon is the inductor charge time tipis is the inductor discharge time and n is the turn ratio of primary windings ON to secondary windings N3 FAN62724 senses the DET voltage Vper and output voltage Vour with LPC and RES pins respectively Therefore Vm n tpy on and Vour can be obtained As a result D pis which is the on time of SR MOSFET can be predicted by Equation 1 As shown in Figure 3 the SR MOSFET is turned on when the SR MOSFET body diode starts conducting and DET voltage drops to zero The SR MOSFET is turned of
6. 5 REEL 2 R11 R12 02 5312305 00 SMD Resistor 1206 12 kQ 5 REEL 1 R5 02 5327305 00 SMD Resistor 1206 27 kQ 5 REEL 1 R4 02 5288721 00 SMD Resistor 0805 887 kQ 1 REEL 1 R2 02 5312405 00 SMD Resistor 1206 120 KQ 5 REEL 1 R1 02 5327405 00 SMD Resistor 1206 270 KQ 5 REEL 1 R6 03 3410239 00 1206 X7R 10 102P 50 V REEL 1 CA 03 3410339 00 1206 X7R 10 103P 50 V REEL 1 C1 03 3410439 00 1206 X7R 10 104P 50 V REEL 1 C2 07 0414801 00 SMD Diode 1N4148 REEL 1 D1 09 108510F 00 MOS FDP085N10A_F102 Fairchild 96 A 100 V 8 5 mQ TO 220 1 Q1 11 B6224MF 11 SMD IC FAN6224M SOP8 Fairchild 1 U1 42 0100532 00 PIN HDR 1 5P 2 54 mm 90 Header 1 CN1 70 PLM0255 00 PCB PLM0255 REVO For FAM6224M 1 5 1 GND DET 42 0100101 00 Copper Green TEST 1 GR 5 ae Note The design of component value depends on system parameters Please follow to the design procedures to determine the appropriate value 1 2013 Fairchild Semiconductor Corporation FEBFAN6224M_CP01 lt Rev 1 0 2 Se FAIRCHILD a eee SEMICONDUCTOR ww fairchildsemi com 6 Revision History Rev Date Description 1 0 0 December 2012 Initial Release 1 0 1 May 2013 Modify Fig 7 Fig 9 Fig 12 1 0 2 November 2014 Corrected Link error WARNING AND DISCLAIMER Replace components on the Evaluation Board only with those parts shown on the parts list or Bill of Materials in the Users Guide
7. Bi FAIRCHILD a ee Se SEMICONDUCTOR ww fairchildsemi com User Guide for FEBFAN6224M _CPO1 Evaluation Board Green Mode Synchronous Rectification Controller for Flyback Converters Featured Fairchild Product FAN6224 Direct questions or comments about this evaluation board to Worldwide Direct Support Fairchild Semiconductor com 2013 Fairchild Semiconductor Corporation FEBFAN6224M_CP01_xxx Rev 1 0 2 e rarai FAIRCHILD SEMICONDUCTOR ww fairchildsemi com Table of Contents 1 TOM CTI OM WAN AN A Na a savteans EEE ETEN Ka A a Re RO EEEE Eataa 3 1 1 Introduction of Linear Predict Timing Control 4 1 2 Features of mWSaver Technology giregt ssscsssssscssnsssessstssneccsaessstessatacenccsssesenessoteons 5 1 3 External Components Design EEGEN anana aana n anana anane aaa nana anana nenen 5 1 4 Design Example for Flyback High Side Rectification 8 1 5 Fine Tuning the Dead Tune Beppe eee s ss sscscssscsstcssncsssecssccsoeesosesseenasnstessnes stone 10 1 6 Assembly of the Daughter Card and En nean an anana anane n anaa nan anana anan anana 11 1 7 Modification of Power Stage for High Side Rectification 12 2 Photograph sama ia EEE eee E ncnsnees nes 13 3 Sechenahie sasa GN aaa a E asasi 14 4 eg CCT IEC Ro et 15 3 Dee RSR EE ee 16 6 Gaul ee EEN ee E 17 2013 Fairchild Semiconductor Corporation 2 FEBFAN6224M_CP01 lt Rev 1 0 2 E FAIRCHILD EEN SEMICONDUCTO
8. Contact an authorized Fairchild representative with any questions This board is intended to be used by certified professionals in a lab environment following proper safety procedures Use at your own risk The Evaluation board or kit is for demonstration purposes only and neither the Board nor this User s Guide constitute a sales contract or create any kind of warranty whether express or implied as to the applications or products involved Fairchild warrantees that its products meet Fairchild s published specifications but does not guarantee that its products work in any specific application Fairchild reserves the right to make changes without notice to any products described herein to improve reliability function or design Either the applicable sales contract signed by Fairchild and Buyer or if no contract exists Fairchild s standard Terms and Conditions on the back of Fairchild invoices govern the terms of sale of the products described herein DISCLAIMER FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY FUNCTION OR DESIGN FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS NOR THE RIGHTS OF OTHERS LIFE SUPPORT POLICY FAIRCHILD S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTE
9. MS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR CORPORATION As used herein 1 Life support devices or systems are devices or systems which a 2 A critical component is any component of a life support device or are intended for surgical implant into the body or b support or system whose failure to perform can be reasonably expected to sustain life or c whose failure to perform when properly used in cause the failure of the life support device or system or to affect its accordance with instructions for use provided in the labeling can be safety or effectiveness reasonably expected to result in significant injury to the user ANTI COUNTERFEITING POLICY Fairchild Semiconductor Corporation s Anti Counterfeiting Policy Fairchild s Anti Counterfeiting Policy is also stated on our external website www fairchildsemi com under Sales Support Counterfeiting of semiconductor parts is a growing problem in the industry All manufacturers of semiconductor products are experiencing counterfeiting of their parts Customers who inadvertently purchase counterfeit parts experience many problems such as loss of brand reputation substandard performance failed applications and increased cost of production and manufacturing delays Fairchild is taking strong measures to protect ourselves and our customers from the proliferation of counterfeit parts Fairchild strongly encourages customers to purchase Fairchild p
10. R ww fairchildsemi c om This user guide supports the evaluation kit for the FAN6224 It should be used in conjunction with the FAN6224 datasheet as well as Fairchild s application notes and technical support team Please visit Fairchild s website at www fairchildsemi com 1 Introduction This document is the evaluation board user manual for the synchronous rectification controller FAN6224 This device is designed for secondary side rectification of flyback converters It is suitable for Continuous Conduction Mode CCM Discontinuous Conduction Mode DCM and Quasi Resonant QR operation With proper design it can be applied for flyback high side and low side rectification as the typical application circuits show in Figure 1 and Figure 2 In addition it is capable of forward free wheeling rectification The maximum operating frequency is up to 140 kHz Green Mode improves no load and light load efficiency by stopping switching to reduce the operating current and switching losses To increase the flexibility of design the loading level to trigger Green Mode is adjustable by the external resistor on the RP pin The user guide focuses on the flyback application and includes design introductions design examples and fabrication of the daughter card The daughter card includes the SR controller FAN6224 a SR MOSFET 100 V 8 5 mQ and detection circuits Vin Ny N2 gt lsr Vour VV FAN6224 D Figure 1
11. arts either directly from Fairchild or from Authorized Fairchild Distributors who are listed by country on our web page cited above Products customers buy either from Fairchild directly or from Authorized Fairchild Distributors are genuine parts have full traceability meet Fairchild s quality standards for handling and storage and provide access to Fairchild s full range of up to date technical and product information Fairchild and our Authorized Distributors will stand behind all warranties and will appropriately address any warranty issues that may arise Fairchild will not provide any warranty coverage or other assistance for parts bought from Unauthorized Sources Fairchild is committed to combat this global problem and encourage our customers to do their part in stopping this practice by buying direct or from authorized distributors EXPORT COMPLIANCE STATEMENT These commodities technology or software were exported from the United States in accordance with the Export Administration Regulations for the ultimate destination listed on the commercial invoice Diversion contrary to U S law is prohibited U S origin products and products made with U S origin technology are subject to U S Re export laws In the event of re export the user will be responsible to ensure the appropriate U S export regulations are followed 2013 Fairchild Semiconductor Corporation 17 FEBFAN6224M_CP01 lt Rev 1 0 2
12. culate the Resistance of R The resistance of R is first selected as 12 KQ as long as it is large enough to clamp negative voltage of the LPC pin R is obtained from 13 R R Ratio po 1 270 KQ Step 5 Calculate Ratiores Select a proper scale down ratio K between 4 and 4 5 The selection is based on the adjustment of dead time and can be fine tuned later In this case 4 11 is selected and RatiOggs is calculated by 14 Ratiorc 23 5 A3 nk 133 411 Ratiores Verify that Ratioggs satisfies 15 If it does not fit into the operating range go back to Step 3 and reconsider the selection of Ratio pc In this case Vour 19 3 32 lt 4 8 RatiOges n 4 3 1 33 The result is acceptable Step 6 Calculate the Resistance of R The resistance of R is first selected as 27 kQ as long as it is large enough to clamp negative voltage of the RES pin R is obtained from 16 R R RatiOges 1 89 1kO As a result the resistance of R Ro Rs and Ry are calculated If the dead time is checked then the four resistors are determined The process of fine tuning the dead time is explained in the following section 2013 Fairchild Semiconductor Corporation 9 FEBFAN6224M_CP01 lt Rev 1 0 2 FAIRCHILD eS eee SEMICONDUCTOR ww fairchildsemi com 1 5 Fine Tuning the Dead Time If SR dead time is too large it is recommended to decrease R or increase R3 Either way Vipc is
13. f by linear predict timing control Body diode of Body diode of Body diode of Body diode of A SR MOSFET SR MOSFET A SR MOSFET SR MOSFET a gt h S Ves ih wi Meel ih Primary Synchr onous Rectifier i Primary Synchr onous Rectifier Primary MOSFET MOSFET i MOSFET MOSFET MOSFET IS A E H ie H Voer Main Vn n Vour Blanking Time ia tuec en AH 0 875VLPc HiGH rnin 0 875Viec HicH VLPC TH HIGH Nemmen gt Va lt ai Si temon t oros temon t cros tips d Ins Figure 3 Waveforms of Linear Predict Timing Controller in CCM DCM QR Flyback 2013 Fairchild Semiconductor Corporation 4 FEBFAN6224M_CP01 lt Rev 1 0 2 Se FAIRCHILD ae ee SEMICONDUCTOR ww fairchildsemi com 1 2 Features of mWSaver Technology Internal Green Mode Stops SR Switching for Lower No Load Power Consumption 300 uA Ultra Low Green Mode Operating Current Synchronous Rectification Controller Suited for High Side and Low Side of Flyback Converters in QR DCM and CCM Operation Suited for Forward Free wheeling Rectification PWM Frequency Tracking with Secondary Side Winding Voltage Detection 140 kHz Maximum Operation Frequency VDD Pin Over Voltage Protection OVP LPC Pin Open Short Protection RES Pin Open Short Protection RP Pin Open Short P
14. increased and the discharge time of Cr capacitor tcrpis is prolonged to decrease the dead time as shown in Figure 4 However note that 12 must be satisfied when increasing Vipc Ver Increased Vic Original Dead Time i Decreased gt Dead Time Figure 4 Decrease SR Dead Time In contrast if SR dead time is too small it is suggested to decrease R or increase R4 Either way Vers is increased and the discharge time of Cr capacitor tcrpis is reduced to increase the dead time as shown in Figure 5 However note that 15 must be satisfied when increasing Vpgs Ver Increased Vres i ter pis i Original iDead Time Increased iDead Time Figure 5 Increase SR Dead Time 2013 Fairchild Semiconductor Corporation 10 FEBFAN6224M_CP01 lt Rev 1 0 2 Ee FAIRCHILD eS eee SEMICONDUCTOR ww fairchildsemi com 1 6 Assembly of the Daughter Card and System Modification of Power Stage for Low Side Rectification Figure 6 shows the flyback system for low side application To mount the daughter card on the low side the modification items are Step 1 Remove the Schottky diode and short the trace Step 2 Cut the connection of transformer terminal A and output ground B Figure 7 shows the daughter card schematic The components of the daughter card include a SR MOSFET 100 V 8 5 mQ the SR controller FAN6224 and detection circuits The connection method is
15. ose R to be equal to 27 KQ and the Ratioggs is based on the calculated result of 14 and 15 R is obtained as below R R Ratioge 1 16 1 4 Design Example for Flyback High Side Rectification Step 1 Define System Parameters Maximum input voltage Vin max 373 V Minimum input voltage Num vm 86 V Output voltage Nour 19 V Turns of the primary side winding N 38 turns Turns of the secondary side winding N 8 turns Turn ratio ny 4 75 Turn ratio n 1 33 Put Vum Max VIN MIN Di and Nour into 9 ae 19 RE 4 75 S 4 75 1 54 4 8 FAN6224 is applicable for this system Step 2 Calculate the Auxiliary Winding Ng N Vo ke es OUT Vip is set between 11 5 V and 26 V Select 15 V and N can be obtained from 10 N is selected as 6 turns Step 3 Calculate the Operating Range of Ratio pc The maximum of Ratio pc is obtained from 11 Vin V OUT n Ration 2e Me 7 53 upc 154 2013 Fairchild Semiconductor Corporation 8 FEBFAN6224M_CP01 lt Rev 1 0 2 Se FAIRCHILD eS eee SEMICONDUCTOR ww fairchildsemi com The minimum of Ratio pc is obtained from 12 Mu uax V OUT n Ratio 16 9 LPC gt 48 Ratiorpc is selected as 23 5 In practice Ratiorpc close to its maximum value is a good start In the following steps if the calculated Ratioggs is over its operating range return to this step and reconsider the selection of Ratiorpc Step 4 Cal
16. rotection Internal Over Temperature Protection OTP 1 3 External Components Design Definition of the System Parameters Maximum input voltage Vinmax Minimum input voltage Vinmm Output voltage Nour Turns of the primary side winding N Turns of the secondary side winding N2 Turns of the auxiliary side winding N3 Turn ratio n is equal to N N Turn ratio n is equal to N N The ratio of LPC resistors Rorpc Ri R2 R2 The ratio of RES resistors Ratiores R3 R4 Ra Flyback Low Side Rectification Refer to the typical application circuit in Figure 1 for the following design procedure Step 1 Confirm the Applicability of the FAN6224 If the system parameters nj Num Max Vin min and Nour Satisfy Vin MIN Wa MAK nun AIN MAX y n OUT n OUT 2 gt 1 54 4 8 then FAN62724 is applicable for this system If 2 is not satisfied some of the parameters need to be redesigned 2013 Fairchild Semiconductor Corporation 5 FEBFAN6224M_CP01 lt Rev 1 0 2 Se FAIRCHILD eS eee SEMICONDUCTOR ww fairchildsemi com Step 2 Select the Capacitance of Crp For low frequency systems under 100 kHz Crp is recommended as 10 nF for high frequency systems from 100 kHz to 140 kHz Crp is recommended as 1 nF Step 3 Calculate the Operating Range of Ratio pc The maximum of Ratio pc is Vus ap Von Ratio lt SZ 1 54 The minimum of Ratio pc is
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