CY8CLEDAC02 A55 Highline 12 W Dimmable LED Driver Reference Design Guide Doc. No. 001-63883 Rev. *C Cypress Semiconductor 198 Champion Court San Jose, CA 95134-1709 Phone (USA): 800.858.1810 Phone (Intnl): 408.943.2600 http://www.cypress.com [+] Feedback Copyrights Copyrights © Cypress Semiconductor Corporation, 2010-2011. The information contained herein is subject to change without notice. Cypress Semiconductor Corporation assumes no responsibility for the use of any circuitry other than circuitry embodied in a Cypress product. Nor does it convey or imply any license under patent or other rights. Cypress products are not warranted nor intended to be used for medical, life support, life saving, critical control or safety applications, unless pursuant to an express written agreement with Cypress. Furthermore, Cypress does not authorize its products for use as critical components in life-support systems where a malfunction or failure may reasonably be expected to result in significant injury to the user. The inclusion of Cypress products in life-support systems application implies that the manufacturer assumes all risk of such use and in doing so indemnifies Cypress against all charges. Trademarks All trademarks or registered trademarks referenced herein are property of the respective corporations. Source Code Any Source Code (software and/or firmware) is owned by Cypress Semiconductor Corporation (Cypress) and is protected by and subject to worldwide patent protection (United States and foreign), United States copyright laws and international treaty provisions. 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Cypress does not assume any liability arising out of the application or use of any product or circuit described herein. Cypress does not authorize its products for use as critical components in life-support systems where a malfunction or failure may reasonably be expected to result in significant injury to the user. The inclusion of Cypress’ product in a life-support systems application implies that the manufacturer assumes all risk of such use and in doing so indemnifies Cypress against all charges. Use may be limited by and subject to the applicable Cypress software license agreement. 2 A55 Highline 12 W Dimmable LED Driver Reference Design Guide, Doc. No. 001-63883 Rev. *C [+] Feedback Contents Contents ................................................................................................................................................................................. 3 Introduction ............................................................................................................................................................................ 5 Reference Design Overview ................................................................................................................................................. 5 Reference Design Contents.................................................................................................................................................. 5 System Specifications .......................................................................................................................................................... 6 Document Revision History .................................................................................................................................................. 6 Design Procedure .................................................................................................................................................................. 7 Overview7 Preliminary Considerations ................................................................................................................................................... 7 Device Constants .......................................................................................................................................................... 7 Input AC Peak Voltage and Minimum DC Voltage ........................................................................................................ 7 Output Voltage and Secondary Winding Voltage .......................................................................................................... 8 VIN Scaling Ratio ........................................................................................................................................................... 8 Volt-Second Product ..................................................................................................................................................... 8 Design of Key Components and Subcircuits ........................................................................................................................ 9 Major Capacitors .................................................................................................................................................................. 9 Input Bulk Capacitor (C3) .............................................................................................................................................. 9 Output Capacitor (C10) ................................................................................................................................................. 9 VCC Capacitors (C8, C9) ................................................................................................................................................ 9 Input Voltage Scaling and Quick Start Subcircuits.............................................................................................................. 10 Input Scaling Subcircuit (R3, R4, R28, R29, C7, Z2) ................................................................................................... 10 Fast Start Subcircuit (R9, R10, Q3, D5) ...................................................................................................................... 10 Flyback Converter Design .................................................................................................................................................. 11 Transformer (T1) Turns Ratio ...................................................................................................................................... 11 Current Sense Resistors (R15, R16) ........................................................................................................................... 11 Transformer (T1) Core Selection ................................................................................................................................. 12 Transformer (T1) Primary Winding Inductance............................................................................................................ 12 Transformer (T1) Turns ............................................................................................................................................... 13 Voltage Sense Resistors (R20, R21) ........................................................................................................................... 14 Flyback FET Switch (Q1) and Output Diode (D7) ........................................................................................................ 14 Supporting Circuits ............................................................................................................................................................. 15 Chopper Circuit (L3, Q2, R5, R6) ................................................................................................................................ 15 Flyback FET (Q1) Drain Clamp (C4, R11, D4) ............................................................................................................ 15 Output Diode (D7) Clamp (C12, R17) ......................................................................................................................... 15 Chopper Diode (D3) Clamp (C14, R7, R31) ................................................................................................................ 15 Over Temperature Protection (R27, R18).................................................................................................................... 15 A55 Highline 12 W Dimmable LED Driver Reference Design Guide, Doc. No. 001-63883 Rev. *C 3 [+] Feedback Copyrights Bill of Materials (BOM) ........................................................................................................................................................ 16 Reference Implementation ................................................................................................................................................. 18 Schematic.................................................................................................................................................................... 18 Board Layout ............................................................................................................................................................... 19 Transformer Specification............................................................................................................................................ 20 Chopper Inductor Specification ................................................................................................................................... 21 Design Measurements ......................................................................................................................................................... 22 Voltage and Current Characteristics ................................................................................................................................... 22 Input Voltage and Current (AC) ................................................................................................................................... 22 Output Current Ripple ................................................................................................................................................. 23 Performance Metrics .......................................................................................................................................................... 24 Efficiency ..................................................................................................................................................................... 24 Power Factor ............................................................................................................................................................... 25 Startup Time ................................................................................................................................................................ 26 Inrush Current (90˚) ..................................................................................................................................................... 27 EMI Compliance ................................................................................................................................................................... 28 4 A55 Highline 12 W Dimmable LED Driver Reference Design Guide, Doc. No. 001-63883 Rev. *C [+] Feedback Introduction Reference Design Overview This document describes a highline 12 W dimmable LED driver reference design using the CY8CLEDAC02 AC-DC power controller device. This design is capable of driving a string of LEDs with a typical forward voltage of 27 V at 350 mA. The CY8CLEDAC02 is a high-performance offline LED driver, designed to interface directly with most conventional phase-cut based wall dimmers. The device uses proprietary digital control technology to provide automatic detection of dimmer type (leading or trailing edge). It automatically generates dimming signals for LED loads and has the ability to dim down to 2 percent. This document has the following sections: Design Procedure: Provides the procedure and basic guidelines to calculate and select key components. Design Measurements: Describes voltage and current characteristics and electrical performance metrics for the reference design. EMI Compliance: Provides results for conducted emissions testing. Reference Design Contents Reference design guide (this document) Schematic Bill of materials (BOM) Reference design database (created using Altium Designer –Summer 09 release) Reference design fabrication files Board 3D model (created using Altium Designer – Summer 09 release) Figure 1. Board 3D Model Images (available in the design package) Safety Notice Circuit protection (fuse or other protection device) is not installed or provided with this board. You must use caution when connecting wire, equipment, or loads to this design. You can add your own protection between the power source and either the line or neutral input connections. A55 Highline 12 W Dimmable LED Driver Reference Design Guide, Doc. No. 001-63883 Rev. *C 5 [+] Feedback System Specifications Table 1. System Specifications Symbol Description Min Typ Max VINAC_RMS Input AC voltage 207 230 253 V ƒLINE Frequency of AC line power 47 50 63 Hz Conducted electromagnetic interference (EMI) ηSYSTEM Comment Meets EN55022 Power factor – System efficiency – Dimmer support 0.8 – 80 – With no dimmer on the line % Phase-cut dimmers Humming IINAC_PEAK Units No audible humming allowed Flickering No visible flickering allowed Cycle-by-cycle peak current – – 2 A In-rush current (90˚) – – 15 A Driver space (X/Y/Z) With leading-edge dimmer A55 form factor VLOAD Load voltage 20 27.2 28.5 V IOUT Output current – 350 – mA IOUT_RIPPLE Output current ripple – – ±5 % Output current accuracy – – ±5 % tSTART-UP Startup time – – 500 ms Specified as a range to allow for variation in LED forward voltage (VF) With no dimmer on the line Document Revision History Document Title: CY8CLEDAC02 A55 Highline 12 W Dimmable LED Driver Reference Design Guide Document Number: 001-63883 Revision ECN# Submission Origin of Date Change Description of Change ** 3020448 09/01/10 CHDP New reference design guide. *A 3095732 11/26/10 CHDP Updated 3D board images and added safety warning (page 5) Updated BOM (page 16-17) Updated schematic (page 18) Updated 2D board images (page 19) Updated the reference design file accompanying this document *B 3123912 12/30/2010 CHDP Updated reference design database *C 3342551 08/11/2011 CHDP Updated package number for L3. Updated Bill of Materials Updated schematic and design database. Distribution: External Posting: Web 6 A55 Highline 12 W Dimmable LED Driver Reference Design Guide, Doc. No. 001-63883 Rev. *C [+] Feedback Design Procedure Overview This section describes how to design a 12 W dimmable LED driver using the CY8CLEDAC02 for specifications listed in Table 1 on page 6. It outlines the design equations used to size components in different subcircuits along with the transformer. The component values suggested here are a good starting point to optimize the design further for efficiency, power factor, and EMI. Preliminary Considerations Device Constants Symbol Value Description tON(max) 5.6 µs Maximum flyback MOSFET on-time KCC 0.7 Constant-current coefficient ZVIN 2.5 kΩ Internal resistance at the VIN pin from the device data sheet tVALLEY1 0.5 µs Time taken by the controller to detect the first valley (typical) Input AC Peak Voltage and Minimum DC Voltage The minimum AC peak voltage is as follows: VINAC _ PEAK (min) = 2 × VINAC _ RMS (min) VINAC _ PEAK (min) = 2 × 207V = 292.7V The maximum AC peak voltage is as follows: V INAC _ PEAK (max) = 2 × V INAC _ RMS (max) V INAC _ PEAK (max) = 2 × 253V = 357.8V This design targets a 60 V ripple on the input bulk capacitor to optimize its lifetime. Therefore, the minimum DC input voltage is determined as follows: VINDC (min) = VINAC _ PEAK (min) − VBULK _ RIPPLE VINDC (min) = 292.7V − 60V = 232.7V A55 Highline 12 W Dimmable LED Driver Reference Design Guide, Doc. No. 001-63883 Rev. *C 7 [+] Feedback Output Voltage and Secondary Winding Voltage As a rule of thumb, provide 5 percent headroom for the output voltage to accommodate for any LED forward voltage variation: VOUT (max) = 105% × V LOAD (max) VOUT (max) = 105% × 27.2V = 28.56V Using a Schottky diode with 0.5 V forward drop for output diode (D7), the secondary winding peak voltage is as follows: V SEC (max) = VOUT (max) + V F _ D 7 V SEC (max) = 28.56V + 0.5V = 29.06V VIN Scaling Ratio The CY8CLEDAC02 uses a scaled and slightly modified version of the input AC voltage to sense the input line characteristics using the VIN pin. The scaling ratio is a ratio of maximum VIN pin voltage to the maximum input AC voltage. Scaling _ ratio = VIN _ RMS (max) , VINAC _ RMS (max) Where VIN_RMS(max) = 1 V. This scales the maximum input AC voltage to 1 VRMS across the internal 2.5-kΩ resistor on the VIN pin. Scaling _ ratio = 1V = 0.004 253V Volt-Second Product The maximum volt-second product (VINtON) is determined using the minimum input bulk-capacitor voltage and maximum possible on time for the flyback MOSFET switch. (VINtON)limit is calculated as: (VIN tON ) lim it = VINDC (min) × tON (max) (VIN tON ) lim it = 232.7V × 5.6μs (VIN tON ) lim it = 1303.12Vμs The (VINtON)limit calculated earlier is the ideal maximum volt-microsecond for this system. This value does not take into account operational stresses imposed with a high value. Using a high value for (VINtON)limit causes higher inductance, greater primary side current, and greater component limits such as peak voltage on the flyback FET and output diode. To minimize stress in the system, use a lower (VINtON)limit, referred to as (VINtON)max. A (VINtON)max of 700 Vµs is used. 8 A55 Highline 12 W Dimmable LED Driver Reference Design Guide, Doc. No. 001-63883 Rev. *C [+] Feedback Design of Key Components and Subcircuits Refer to the schematic provided in the Reference Implementation section on page 18 for component designators. Major Capacitors Input Bulk Capacitor (C3) The input bulk capacitor (C3) is required to maintain enough input power to sustain constant output power even as the input voltage droops. The maximum input power is: PIN (max) = PIN (max) = VOUT (max) × I OUT η SYSTEM (min) 27.2V × 350mA = 11.9W 80% Calculate the minimum capacitance for C3 using the following equation: ⎛1 1 ⎛ ⎞⎞ VINDC (min) ⎟⎟ 2 × PIN (max) × ⎜ + arcsin⎜ ⎜ 4 2π ⎜ 2 ×V ⎟⎟ INAC _ RMS (min) ⎠ ⎠ ⎝ ⎝ C3 = 2 2 [VINAC _ PEAK (min) − VINDC (min) ] × f LINE (min) ⎛1 1 ⎛ 232.7V 2 × 11.9W × ⎜⎜ + arcsin⎜ ⎝ 2 × 207V ⎝ 4 2π C3 = 2 2 [292.7V − 232.7V ] × 47 Hz ⎞⎞ ⎟ ⎟⎟ ⎠⎠ = 6.10 μF This design uses a standard 6.8-µF capacitor for C3 rated at 400 V. Output Capacitor (C10) As a rule of thumb, use a minimum of 1 µF for every 10 mA of LED current for the output bulk capacitance. I OUT 10mA 350mA C10 = 1μF × = 35μF 10mA C10 = 1μF × When selecting component values, consider the lifetime and ripple current requirements of the design. This design uses a 33-µF capacitor rated at 35 V. VCC Capacitors (C8, C9) Size the VCC capacitor (C9) such that it can sustain power to the chip during the dimmer detection cycles because the bias winding does not supply energy to charge it during this period. The dimmer detection time is four AC half-cycles. The maximum dimmer detection time is: t DETECTION = t DETECTION = 1 f LINE (min) × 4 2 1 4 × = 42.55ms 47 Hz 2 A55 Highline 12 W Dimmable LED Driver Reference Design Guide, Doc. No. 001-63883 Rev. *C 9 [+] Feedback Calculate minimum CVCC using the standard capacitor formula: t DETECTION dt = I CC ( MAX ) × dv VCCST ( MIN ) − VCCUVL ( MAX ) 42.55ms = 4.5mA × = 63.83μF 11V − 8V CVCC = I CVCC Choose a standard value higher than the calculated value. This design uses a 68 µF, 35-V capacitor for C9 and a 2.2-µF capacitor for C10. C10 is a filter capacitor required to filter any high-frequency noise from the boost and flyback converters. Input Voltage Scaling and Quick Start Subcircuits Input Scaling Subcircuit (R3, R4, R28, R29, C7, Z2) The scaling resistors are determined using the scaling ratio. Select R29 = 56 kΩ to start with. The sum of R3 and R4 can be determined as follows: Scaling _ ratio = Z VIN ( R3 + R 4) + R 29 + Z VIN 2.5kΩ ( R3 + R 4) + 56kΩ + 2.5kΩ ∴ R3 + R 4 = 574kΩ 0.004 = Calculate the total peak power on scaling resistors: (VINAC _ PEAK (max)) 2 PR 3 + R 4 = R3 + R 4 (357.8V ) 2 PR 3 + R 4 = = 223mW 574kΩ This design uses two 301 kΩ, 1206 package, thick-film resistors for R3 and R4. Choose the 1206 footprint for these resistors to allow for the 200 V working voltage requirements for each resistor. Typically, the total resistance is divided equally to balance the power dissipation. C7 = 1 nF, a filter capacitor required to filter any high- frequency noise from the boost and flyback converters. The following are recommended component values: R28 = 20 kΩ Z2, Reverse breakdown voltage of 20 V Fast Start Subcircuit (R9, R10, Q3, D5) Components R9, R10, Q3, and D5 provide a path to fast charge CVCC, which is required to meet the 500 ms startup time target for the design. Typically, using one-eighth the value of R3 and R4 for R9 and R10 is enough to meet the startup time requirement. R9 = R10 = R3 R 4 = = 37.63kΩ 8 8 The design uses two 32.4 kΩ, 1210 package resistors for R9 and R10 to meet the startup time target. 10 A55 Highline 12 W Dimmable LED Driver Reference Design Guide, Doc. No. 001-63883 Rev. *C [+] Feedback The maximum power across R9 and R10 is (VINAC _ PEAK (max)) 2 PR 9 + R10 = R9 + R10 (357.8V ) 2 PR 9 + R10 = = 1.976W 32.4kΩ + 32.4kΩ ∴ PR 9 = PR10 = 0.988W R9 and R10 are selected in 1210 packages because the 0.988 W power dissipation is only for the first 100 ms during startup. The quick start transistor (Q3) must be a depletion type MOSFET with appropriate current rating. The quick start diode (D5) can be a small signal silicon diode with appropriate voltage rating. This design uses a 150 V rated diode. Flyback Converter Design Transformer (T1) Turns Ratio To determine the transformer (T1) turns ratio, use the minimum target switching frequency ƒSW(maxop_targ). With a target switching frequency of 120 kHz for optimum performance and efficiency in a small transformer package, derive the turns ratio as follows: Starting with the equation for valley mode switching: t PERIOD(max) = tON (max) + tOFF (max) + tVALLEY 1 t PERIOD(max) = 1 f SW (max op _ t arg) = VIN tON (max) VINDC (min) + VIN tON (max) N TR ( rec ) × VSEC (max) + tVALLEY 1 1 700Vμs 700Vμs = + + 0.5μs 120kHz 232.7V NTR ( rec ) × 29.06V ∴ N TR ( rec ) = 4.99 NTR(rec) is the recommended NTR value. However, for transformer manufacturability, this design uses a NTR = 5. Now that the NTR is confirmed, calculate the actual minimum switching frequency for the design with the previous equation as: f SW (max op ) = 117.47kHz Current Sense Resistors (R15, R16) To calculate the current sense resistor, use the following equation: R Isense = 1 N TR × η XFMR × × KCC I OUT 2 R Isense = 1 5 × 0.95 × × 0.7 = 4.75Ω 2 0.35 Use two resistors in parallel for precise control. The design uses a 10 Ω, 1206-package resistor (R15) in parallel with an 8.06 Ω, 1206-package resistor (R16). A55 Highline 12 W Dimmable LED Driver Reference Design Guide, Doc. No. 001-63883 Rev. *C 11 [+] Feedback The actual RISENSE resistance is: R15 × R16 R15 + R16 10Ω × 8.06Ω = = 4.33Ω 10Ω + 8.06Ω R Isense = R Isense The actual value for RIsense is slightly different from the calculated value. The resistance is later adjusted to match the actual transformer efficiency. Calculate the maximum peak power across R15 and R16. (V REGTH ) 2 R15 (1.8V ) 2 = = 324mW 10Ω PR15 _ PEAK (max) = PR15 _ PEAK (max) PR16 _ PEAK (max) PR16 _ PEAK (max) (V REGTH ) 2 = R16 (1.8V ) 2 = = 402mW 8.06Ω The RMS power for ISENSE resistors is roughly one-ninth the peak power: PR15 _ RMS (max) = PR15 _ RMS (max) 9 324mW = = 36mW 9 PR16 _ RMS (max) = PR16 _ RMS (max) PR15 _ PEAK (max) PR16 _ PEAK (max) 9 402mW = = 44.67 mW 9 Transformer (T1) Core Selection Size and power requirements for the design typically govern core selection. Consult with a transformer manufacturing company (such as Renco Electronics) to determine the most suitable core to meet form factor and power requirements. This design uses an EP13 core. Transformer (T1) Primary Winding Inductance The amount of power the transformer needs to supply to meet the output power requirement is: PXFMR (max) = PXFMR (max) = VSEC (max) × I OUT η xfmr 29.06V × 350mA = 10.71W 95% Use an estimate value of 95 percent for ηXFMR for calculations. Calculate the maximum magnetizing inductance as follows: 12 A55 Highline 12 W Dimmable LED Driver Reference Design Guide, Doc. No. 001-63883 Rev. *C [+] Feedback LM (max) = (V IN t ON ) 2max × f SW (max Op ) × η xfmr 2 × PXFMR (max) (716.72Vμs ) 2 × 117.47 kHz × 95% = = 2676μH 2 × 10.71W LM (max) The minimum magnetizing inductance is calculated as follows: 2 × PXFMR (max) L M (min) = L M (min) 2 V ⎞ f SW (max op ) × ⎛⎜ REGTH ⎟ R Isense ⎠ ⎝ 2 × 10.71W = = 1055μH )2 117.47 kHz × (1.8V 4.33Ω This design uses a transformer with a 2360 µH primary inductance which is approximately the 0.9 of LM(max) allowing margin for manufacturing tolerances. Transformer (T1) Turns Calculate the number of turns on the primary winding as follows: N PRI (min) = (VIN tON ) max Bmax × Ae N PRI (min) = 700Vμs = 156.6 300mT × 14.9mm 2 The values for maximum flux density, Bmax, and core area, Ae values are from the EP13 transformer core data sheet. This design uses 200 turns on the primary winding based on mechanical constraints such as uniform windability for the selected transformer core. Calculate the number of turns on the secondary winding as follows: N SEC = N PRI N TR N SEC = 200 = 40 5 This design uses 40 turns on the secondary winding. The number of turns in the bias (auxiliary) winding is determined by calculating the minimum turns ratio from secondary to auxiliary as follows: N TR − SEC _ AUX (min) = N TR − SEC _ AUX (min) = V SEC (max) + V F _ D 7 V RB _ Z 1 + V F _ D 6 29.06V + 0.5V = 1.88 15V + 0.7V This design uses 20 turns on the auxiliary winding. A55 Highline 12 W Dimmable LED Driver Reference Design Guide, Doc. No. 001-63883 Rev. *C 13 [+] Feedback Voltage Sense Resistors (R20, R21) Calculate the VSENSE resistors as follows: ⎛ VSENSENOM N SEC × ⎜1 − V SEC ( Max ) N AUX ⎜ R 20 = R 21 × ⎜ V N ⎜ SENSENOM × SEC ⎜ V N AUX SEC ( Max ) ⎝ ⎞ ⎟ ⎟ ⎟ ⎟ ⎟ ⎠ 1.538V 40 ⎞ ⎛ × ⎜1 − ⎟ V 29 . 06 20 ⎜ ⎟ = 20.27kΩ R 20 = 2.4kΩ × ⎜ 1.538V 40 ⎟ × ⎜ ⎟ ⎝ 29.06V 20 ⎠ Select R21 = 2.4 kΩ This design uses 22 kΩ for R20. Flyback FET Switch (Q1) and Output Diode (D7) The flyback FET switch should be able to withstand a voltage of at least: V DS (max) = 1.3 × (V INAC _ PEAK (max) + N TR × V SEC (max) ) V DS (max) = 1.3 × (357.8V + 5 × 29.06V ) = 654.03V Additionally, carefully select the flyback FET to have an optimum balance between AC and DC losses. This design uses an 800 V, 4.6 A FET for Q1 for optimum efficiency. The output diode should be able to withstand a reverse voltage of at least: V R _ D 7 = 1.3 × (V INAC _ PEAK (max) / N TR + V SEC ( Max ) ) V R _ D 7 = 1.3 × (357.8V / 5 + 29.06V ) = 130.81V Additionally, the diode should be able to sustain the maximum secondary current: I SEC (max) = NTR × I PRI (max) , Calculate the maximum primary peak current (IPRI(max)) as follows: I PRI (max) = V REGTH RISENSE I PRI (max) = 1.8V = 0.416 A 4.33Ω Therefore: I SEC (max) = 5 × 0.416 A = 2.08 A This design uses a 200 V, 3A diode for D7. 14 A55 Highline 12 W Dimmable LED Driver Reference Design Guide, Doc. No. 001-63883 Rev. *C [+] Feedback Supporting Circuits Chopper Circuit (L3, Q2, R5, R6) Selection of chopper components plays a significant role in overall dimmer compatibility. The following chopper component values are recommended for most high line (230 VAC) designs and are based on extensive testing of dimmers. R5 = 220 Ω, 2 W, the chopper drain resistor R6 = 59 Ω, 1/2 W, chopper source (current limit) resistor L3 = 5 mH, chopper inductor Q2, the chopper FET switch, should be selected as specified (or similar) in the Bill of Materials (BOM) section on page 16. Flyback FET (Q1) Drain Clamp (C4, R11, D4) Adding an RCD snubber limits the voltage spike on the drain of the flyback MOSFET at turn-off. The energy stored in the leakage inductance of the transformer is then dissipated over the rest of the switching period. For maximum efficiency, minimize the leakage inductance. Final component values are determined after careful characterization of first prototypes. This design uses a 2.2-nF capacitor for C4 and a 330 kΩ, 1206-package resistor for R11. D4 is a 1000 V, 1 A diode. Output Diode (D7) Clamp (C12, R17) Adding an RC clamp on the output diode improves fidelity of the ISENSE signal. Final component values are determined after careful characterization of first prototypes. This design uses 100 pF for C12 and 107 Ω, 1206-package resistor for R17. Chopper Diode (D3) Clamp (C14, R7, R31) Adding an RC clamp on the chopper diode improves conducted EMI performance of the design. Final component values are determined after careful characterization of first prototypes. This design uses 68 pF for C14 and 3.4 kΩ, 1206-package resistor for R7 and R31. Over Temperature Protection (R27, R18) The reference design does not implement over temperature protection (OTP). For more information on OTP and operation of the VT pin, refer to the CY8CLEDAC02 device data sheet. This design has a 0-Ω resistor for R27, which is a placeholder for an appropriate NTC resistor. R18 is 20 kΩ, which disables OTP on the VT pin. A55 Highline 12 W Dimmable LED Driver Reference Design Guide, Doc. No. 001-63883 Rev. *C 15 [+] Feedback Bill of Materials (BOM) This section lists the final BOM for this design. Only critical components are covered in the design procedure. Others that remain fixed for any high line (230 VAC) design and are required for the device to operate correctly are listed in the BOM. Table 2. Bill of Materials Item Component Count Component Specifications Manufacturer Manufacturer Part No. 1 1 BR1 DB107,SMD Diodes Inc DF10S 2 1 C1 0.22 uF, 310VAC, X2, Film Vishay/BC Components BFC2 338 20223 3 1 C2 0.01 uF, 400VDC, Metal Poly Panasonic - ECG ECQ-E4103KF 4 1 C3 6.8 uF, 450V - E-Cap, 1000 hours at 105 °C United Chemi-con EKXG451ELL6R8MJ20S 5 1 C4 Ceramic, 2200 pF, 1K V, 10%, X7R, 1206 Murata Electronics GRM31BR73A222KW01L 6 1 C5 Ceramic, 220 pF, 6.3 V, 5%, COG, 0603 AVX Corporation 06036A221JAT2A 7 1 C6 Ceramic, 22 pF, 50 V, 5%, COG, 0603 Murata Electronics GQM1885C1H220JB01D 8 3 C7, C15, C16 Ceramic, 1 nF, 50 V,10%, X7R, 0603 Panasonic ECG ECJ-1VB1H102K 9 1 C8 Ceramic, 2.2 uF, 25 V, 10%, X7R, 1206 Murata Electronics GRM31MR71E225KA93L 10 1 C9 68 uF, 25 V, Electrolytic, 1000 hours at 105 °C Panasonic - ECG ECE-A1EKG680 11 1 C10 33 uF, 50 V, Electrolytic, 2000 hours at 105 °C Nichicon UPW1H330MEH 12 1 C12 Ceramic, 100 pF, 630 V, 10%, Kemet X7R, 0805 13 1 C14 Ceramic, 68 pF, 630 V, 10%, X7R, 0805 Kemet 14 1 C20 SMD-1206 footprint Do Not Populate Do Not Populate 15 1 CY1 1000 pF, 300VAC, 20%, Metalized Polypropylene Film Kemet R413F11000000M 16 2 D1, D3 Fast Recovery, 1A, 600 V , SMA Micro Commercial Company ES1J-TP 17 3 D4, D8, D9 Fast Recovery, 1000V, 1A, SMB Diodes Inc RS1MB-13-F 18 3 D2, D5, D6 100 V, Iavg = 200 mA, SOD123 Diodes Inc BAV19W-7-F 19 1 D7 Schottky, 3A, 150 V, SMB ST Microelectronics STPS3150U 20 1 F1 Inline (not present on board) – 250 V, 2A, slow blow time lag Littlefuse Inc. 0215002.MXEP 21 2 L1, L2 4.7 mH, EMI Filter Inductor Renco RL-5480-2-4700 L3 5 mH, 0.18A , Core: EP7, Refer schematic for pinout (1) Renco (2) Wurth Electronics Midcom 22 16 1 Notes C0805C101KBRACTU C0805C680KBRACTU (1) RLCY-1006 (2) 750 311 909 DNP Not supplied with board Custom Component A55 Highline 12 W Dimmable LED Driver Reference Design Guide, Doc. No. 001-63883 Rev. *C [+] Feedback Item Component Count Component Specifications Manufacturer Manufacturer Part No. Notes 23 1 Q1 N-Ch MOSFET, 800 V, 4.6A, D-PAK Infineon Technologies SPD04N80C3 24 1 Q2 N-Ch MOSFET, 600 V, 2A, D-PAK Vishay/Siliconix IRFRC20TRPBF 25 1 Q3 N-Ch MOSFET, 600 V, 0.35A, Depletion mode, SOT23 Infineon Technologies BSS126 L6327 26 1 Q6 P-Ch MOSFET, 50 V, 130 mA, 300 mW, SOT23 Diodes Inc. BSS84-7-F 27 2 R1, R2 4.7K, 1/4W, 5%, 0805 Vishay/Dale CRCW08054K70JNEA 28 2 R3, R4 301K, 1/4W, 1%, 1206 Vishay/Dale CRCW1206301KFKEA 29 1 R5 220R, 2W, 5%, Metal Film Vishay/BC Components PR02000202200JR500 30 1 R6 59R, 1/2W, 5%, 1210 Panasonic-ECG ERJ-14NF59R0U 31 2 R7, R31 3.4K, 1/4W, 1%, 1206 Vishay/Dale CRCW12063K40FKEA 32 2 R8,R13 100K, 1/10W, 1%, 0603 Vishay/Dale CRCW0603100KFKEA 33 2 R9, R10 32.4K, 1/2W, 1%, 1210 Panasonic-ECG ERJ-14NF3242U 34 1 R11 330K, 1/4W, 5%, 1206 Vishay/Dale CRCW1206330KJNEA 35 1 R12 47R, 1/10W, 1%, 0603 Vishay/Dale CRCW060347R0FKEA 36 1 R14 100, 1/10W, 1%, 0603 Vishay/Dale CRCW0603100RFKEA 37 1 R15 8.06R, 1/4W, 1%, 1206 Vishay/Dale CRCW12068R06FKEA 38 1 R16 10R, 1/4W, 1%, 1206 Vishay/Dale CRCW120610R0FKEA 39 1 R17 107R, 1/4W, 5%, 1206 Vishay/Dale CRCW1206107RFKEA 40 2 R18, R28 20K, 1/10W,1%, 0603 Panasonic ECG CRCW060320K0FKEA 41 1 R19 10R, 1/10W, 1%, 0603 Vishay/Dale CRCW060310R0FKEA 42 1 R20 22K, 1/10W, 1%, 0603 Vishay/Dale CRCW060322K0FKEA 43 1 R21 2.4K, 1/10W, 1%, 0603 Vishay/Dale CRCW06032K40FKEA 44 1 R22 100K, 1/4W, 1%, 1206 Panasonic-ECG ERJ-8ENF1003V 45 1 R26 SMD-0603 footprint Do Not Populate Do Not Populate 46 1 R27 0R, 1/10W, jumper, 0603 Panasonic ECG ERJ-3GEY0R00V 47 1 R29 56K, 1/10W, 1%, 0603 Vishay/Dale CRCW060356K0FKEA 48 1 R30 200K, 1/10W, 5%, 0603 Vishay/Dale CRCW0603200KJNEA 49 2 R32, R33 SMD-1206 footprint Do Not Populate Do Not Populate DNP (1) Renco (1) RLCY-1015 Custom Component 50 1 T1 Lp=2.36 mH at 10 KHz, Bobbin: EP13 surface mount, Npri = 200, Nsec = 40, Naux = 20, see schematic for pinout 51 1 U1 LED off-line Controller Cypress CY8CLEDAC02 52 1 Z1 Zener, 15 V, 500 mW, SOD80 NXP Semiconductor BZV55-B15,115 53 1 Z2 Zener, 20 V, 300 mW,SOD323 NXP Semiconductor BZX384-B20,115 (2) Wurth Electronics Midcom (2) 750 311 843 A55 Highline 12 W Dimmable LED Driver Reference Design Guide, Doc. No. 001-63883 Rev. *C DNP 17 [+] Feedback 18 AC_F R2 4.7K - 0805 RL-5480-2-4700 4.7mH L2 AC_Lin 3 4 D8 DF10S- SMD AC1 AC0 BR1 RS1M- SMD RS1M- SMD D9 - + 2 1 R30 200K GND 2 S Cypress reserves the right to make changes without further notice to the materials described herein. Cypress does not assume any liability arising out of the application or use of any product or circuit described herein. Cypress does not authorize its products for use as critical components in life-support systems where a malfunction or failure may reasonably be expected to result in significant injury to the user. The inclusion of Cypress’ product in a life-support systems application implies that the manufacturer assumes all riskof such use and in doing so indemnifies Cypress against all charges. RIsense GND HVdrn C5 220pF 100 R14 47 BSThvin GND IRFRC20TRPBF 0 R27 5 9 6 7 C15 NTC 1nF Vin VCC 20K R18 VT Boost Vsense CY8CLEDAC02 GND PAD Isense Output U1 S 3 8 4 1 2 1 SD R6 59 - 1210 R8 100K BSTsrc Q2 BSTdrn HVin R31 3.4K - 1206 R5 220 - 2W R7 3.4K - 1206 IRFRC20 D GND 0-ohm resistor (R27) to be replaced with NTCif needed. Place close to EMI inductors. Isense BSTdrnin L3 5mH - EP7 4 G Output 10nF, 400V - MPP C2 GD R12 R13 100K R15 8.06R, 1% - 1206 Q1 1 R29 56K R4 301K - 1206 Vin2 R3 301K - 1206 C14 68p - 0805 3 Disclaimer: CYPRESSMAKESNO WARRANTY OFANY KIND, EXPRESSORIMPLIED, WITH REGARD TO THIS MATERIAL, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIESOFMERCHANTABILITY AND FITNESSFORA PARTICULARPURPOSE. R26 DNP SPD04N80C3 R16 10R, 1% - 1206 Q6 BSS84 VinQZ BZX384-B20,115 Z2 Vin1 3 G R28 20K VinRZ 2 SPD04N80C3 D 1 3 GND C16 1nF GS BSS84 D R33 DNP - 1206 R32 DNP - 1206 ES1J D1 ES1J BST Vsense Vin VCC GND C7 1nF BSS126 1 GS BSS126 D C3 6.8uF, 450V - E-Cap 3 This document contains confidential information which might be proprietary to cypress semiconductor. No part of its contents, may be used, copied, disclosed, or conveyed to any party in any manner whatsoever without prior written permission from cypress semiconductor. BST BAV19W-7-F D2 12W, 27.2V, 350 mA design 230 +/-10% 47-53 Hz All discrete R and C components are 0603 unless noted otherwise BSThv D3 1 Fuse F1 is not on the PCB. F1 is an in-line fuse. L C1 22nF, 310V - X2 4.7K -0805 R1 AC_Nin RL-5480-2-4700 4.7mH L1 6 2A 250VACFuse F1 AC_N 2 NOTE: Fuse F1 place in-line. N C8 2.2uF, 25V - 1206 D5 C4 C9 10 R19 22pF, 50V C6 BAV19W-7-F D6 RS1M- SMD D4 VauxD Fltr R11 330K - 1206 68uF, 25V - E-Cap BAV19W-7-F Z1 BZV55-B15 QC3 Q3 QC2 R10 32.4K - 1210 QC1 R9 32.4K - 1210 2.2nF, 1kV - 1206 2.4K R21 R20 22K Vaux 5 4 1 6 10 D7 107 - 1206 R17 C10 33uF, 50V - 7343-43 (EIA) STPS3150-SMD AGND LEDsrc AGND CY1 OSnub C20 + AGND - R22 100K - 1206 LED+ C12 100p - 0805 DNP - 1206 n primary:secondary:auxilliary High-line n 200:40:20 EP13 2 T1 GND 1nF300VACY-CAP Reference Implementation Schematic The guidelines discussed in this document provide a method to arrive at first-pass components used to prepare a prototype for this design. Based on functional and performance data gathered while testing this prototype board, different circuit components are tuned to meet the end system requirements. The transformer specifications obtained from the calculations may not always result in a feasible winding structure. For example, for the number of turns in the primary winding, a value larger than the minimum number calculated from the primary winding section may be necessary. In this design, NP is selected as 200 turns. In addition, the primary magnetizing inductance may have to be increased to reduce the switching frequency and hence the switching losses in the system. The current sense resistance may have to be tuned based on the efficiency of the transformer and the accuracy of its turnsratio. Figure 2 on page 18 is the final schematic for this 12 W reference design and is in the document package. Figure 2. Reference Design Schematic 2 A55 Highline 12 W Dimmable LED Driver Reference Design Guide, Doc. No. 001-63883 Rev. *C [+] Feedback Board Layout Figure 3. Reference Design Board Layout Top Layer Bottom Layer A55 Highline 12 W Dimmable LED Driver Reference Design Guide, Doc. No. 001-63883 Rev. *C 19 [+] Feedback Transformer Specification The transformer is one of the most important components in this LED driver circuit. As explained in previous sections, in addition to the two standard windings, typical flyback converter transformers incorporate a third winding. In this circuit, it provides voltage sensing for output voltage regulation and no-load protection by the CY8CLEDAC02 device. This winding, called the bias or auxiliary winding also provides supply voltage (VCC) to the CY8CLEDAC02. The specifications of the transformer for this reference design are as follows: Transformer manufactured by Renco Electronics, Inc. or Würth Elektronik Electrical specifications Primary inductance: 2360 µH at 10 kHz Primary leakage inductance: Renco Electronics ≤ 44 µH at 10 kHz o Würth Elektronik ≤ 25 µH at 10 kHz Peak primary current: 380 mA Peak secondary voltage: 29 V Peak secondary current: 350 mA Primary-to-secondary turns ratio: 5-to-1 Secondary-to-auxiliary turns ratio: 2-to-1 Flyback switching frequency: 120 kHz to 150 kHz Materials Core: EP13 (Ferrite material TDK PC40 or equivalent) Bobbin: EP13 Magnet wire: Type 2UEW Triple insulated wire: TEX-E or equivalent Layer insulation tape: 3M1350f-1 or equivalent Teflon sleeve Finishing 20 o Varnish the complete assembly A55 Highline 12 W Dimmable LED Driver Reference Design Guide, Doc. No. 001-63883 Rev. *C [+] Feedback Chopper Inductor Specification The Chopper Inductor is one of the most important components in this LED driver circuit. This component boosts the input voltage during dimmer operation, allowing the CY8CLEDAC02 to drive the LEDs with more than 70 percent power factor. The specifications of the Chopper Inductor for this reference design are as follows: Inductor manufactured by Renco Electronics, Inc. or Wurth Electronics Midcom Electrical specifications Inductance: 5000 µH at 10 kHz Saturation current: 180 mA minimum Materials Core: EP7 (Ferrite material TDK PC40 or equivalent) Bobbin: EP7 Magnet wire: Type 2UEW Finishing Varnish the complete assembly A55 Highline 12 W Dimmable LED Driver Reference Design Guide, Doc. No. 001-63883 Rev. *C 21 [+] Feedback Design Measurements This section documents the measurements of this LED driver reference design. Voltage and Current Characteristics Input Voltage and Current (AC) Figure 4 shows the input VAC and IAC. VAC is the blue waveform (Channel 1). IAC is the green waveform (Channel 4). Figure 4. Input Voltage and Current at 230 VAC 50 Hz 22 A55 Highline 12 W Dimmable LED Driver Reference Design Guide, Doc. No. 001-63883 Rev. *C [+] Feedback Output Current Ripple Figure 5 shows the output current ripple. Figure 5. Current Ripple into ~27 V Load A55 Highline 12 W Dimmable LED Driver Reference Design Guide, Doc. No. 001-63883 Rev. *C 23 [+] Feedback Performance Metrics This section documents the system performance metrics of this reference design including efficiency, power factor, startup time, and inrush current. All metrics are collected with no dimmer on the line. Efficiency Efficiency is one of the most important performance metrics for any power supply system. Higher driver efficiency reduces the losses that are otherwise dissipated as heat. Figure 6. Variation of Efficiency with Input AC Voltage Efficiency vs. VAC Input 90.00% 88.00% 86.00% Efficiency 84.00% 82.00% 80.00% 78.00% 76.00% 74.00% 72.00% 70.00% 206 210 214 218 222 226 230 234 238 242 246 250 254 VAC (V) Note The measurements are made after the driver runs for 30 minutes to stabilize the working temperature. 24 A55 Highline 12 W Dimmable LED Driver Reference Design Guide, Doc. No. 001-63883 Rev. *C [+] Feedback Power Factor Figure 7. Power Factor versus Input AC Voltage Power Factor vs. VAC Input 0.9 0.88 0.86 Power Factor 0.84 0.82 0.8 0.78 0.76 0.74 0.72 0.7 206 210 214 218 222 226 230 234 238 242 246 250 254 VAC (V) Note The measurements are made after the driver runs for 30 minutes to stabilize the working temperature. A55 Highline 12 W Dimmable LED Driver Reference Design Guide, Doc. No. 001-63883 Rev. *C 25 [+] Feedback Startup Time This metric represents the time taken by the LED driver output current to ramp up to 90 percent of the maximum LED current on startup (when VCC voltage for the device starts ramping up). In the following figure, the waveforms are as follows: blue (Channel 1) indicates VCC, teal (Channel 2) indicates output voltage for CY8CLEDAC02, and green (Channel 4) indicates output current. The startup time is 357 ms, well within the 500 ms requirement listed in Table 1 on page 6. Figure 8. Startup Time 26 A55 Highline 12 W Dimmable LED Driver Reference Design Guide, Doc. No. 001-63883 Rev. *C [+] Feedback Inrush Current (90˚) Inrush current (90°) is the input power applied at its peak voltage. In the following figure, the waveforms are as follows: blue (Channel 1) indicates input voltage after the rectifier and green (Channel 4) indicates input current. The inrush current is 6.20 A, well within the 15 A limit listed in Table 1 on page 6. Figure 9. Inrush Current A55 Highline 12 W Dimmable LED Driver Reference Design Guide, Doc. No. 001-63883 Rev. *C 27 [+] Feedback EMI Compliance This section captures compliance test data from conducted EMI measurements of this reference design according to standard EN55022. Conducted emissions data for both line and neutral AC inputs is collected at 230 VAC, 60 Hz input. Figure 10. Conducted EMI Performance (Peak Plots for Line and Neutral) 28 A55 Highline 12 W Dimmable LED Driver Reference Design Guide, Doc. No. 001-63883 Rev. *C [+] Feedback