DI-21参考设计 TOPSwitch-GX ® 45 W通用输入的LCD显示器外部适配器 应用 器件 输出功率 输入电压 输出电压 拓扑结构 LCD显示器 TOP247YN 45 W 90 – 265 VAC 12 V 反激式 设计特色 • 高效率，90 VAC时效率>82% • 元件数量少 • 极低的EMI－频率调制帮助在输出接地时满足EN55022B和FCC B的要求 • • • • 空载功耗低，115 VAC输入时<250 mW 线欠压检测(UV)和过压(OV)浪涌保护 通过4 kV差模和共模浪涌测试(EN61000-4-5) 通过4 kV/100 kHz震铃波测试(IEEE C62.41) D1 D2 F1 L 3.15 A 90 - 265 VAC N CX1 330 nF X2 to L1 10 mH 1.4 A RT1 5 72.8 A C1 100 MF 400 V C2 20 nF 1 kV R5 D3 VR1 P6KE 200 C3 4.7 nF 1 kV D5 UF4005 R6 标称的UV和OV设置点根据下式计算： • VUV = (50 µA x R1) + 2.5 V, VOV= (R1 x 225 µA) + 2.9 V • C2给高压母线提供高频旁路，减小高频EMI。 • C3降低箝位齐纳管的温度，提高效率。跟C3串连的R18阻尼漏 • 在输出整流管D7上用磁珠代替RC缓冲电路可降低空载功耗。 • L5和L6在高频时(>10 MHz)减小共模干扰。 • T1屏蔽绕组（引脚2-3）减小了EMI。R7阻尼容性屏蔽电流引起 的振荡。 • 电容C12消除开机输出过冲。 • 反馈补偿通过连接到TL431参考放大器(U3)两端的C11和R12来 完成，正确选择与光耦串联的电阻R10。 D D4 S R8 15 k7 L3 Bead 2 7, 9 3 10,12 1 R1 2 M7 0.5 W Note: Beads L3 and L4 are placed on D7 anode leads L4 Bead T1 5 D7 MBR20100 D6 1N4148 4 6 TOPSwitch-GX U1 CONTROL CONTROL C TOP247YN C6 1 MF 50 V C7, C8 680 MF 35 V L2 3.3 MH, 5 A X F C4 100 nF RTN U2 LTV817A R11 1 k7 R10 470 7 R9 6.8 7 C5 47 MF 10 V L6 1T Through Ferrite Bead 12 V, 3.75 A C10 100 nF C9 220 MF 35 V L GND L5 3T Ground Wire Through Ferrite Bead 设计要点 CY1 R7 2.2 nF 220 7 Y1 R18 68 7 0.5 W R4 D1-D4 RL205 2 A, 600 V 的EE30磁芯和高电感来进一步提高效率。 极振荡。 工作方式 图1的设计使用了TOP247YN和它的很多特性。用一个2 MΩ的电阻 (R1)完用UV和OV（各为100 V和450 V）功能。欠压消除了开／关 机时的输出抖动，过压在输入电压瞬态和长时间浪涌时提供保 护，并省掉了MOV。R8将TOP247YN的内部限流点设置为标称值 的50％。R4-R6使限流点随线电压进一步降低，在线电压变化时 提供大约恒定的过载功率。选择较大型号的TOPSwitch-GX可降低 R4-R6 2.7 M7 导通损耗，提高效率（不改变电路或增加过载功率），可使用小 C12 22 MF 25 V R13 38.3 k7 1% C11 47 nF R12 4.7 k7 U3 TL431 R14 10 k7 1% PI-3003-100708 图1. 使用TOPSwitch-GX的45 W LCD显示器适配器 www.powerint.com October 2008 70 QP Limit Line Amplitude (dBmV) 60 PI-3004-073102 80 AV Limit Line 50 磁芯材料 EE30 TDK PC40EE30-Z or equivalent, gapped for ALG of 1045 nH/t² 骨架 E130 12 pin (Yih Hwa YW-016 or equivalent) 绕组细节 Shield: 10T, 2 × 28 AWG Primary: 22T, 25 AWG Bias: 3T, 4 × 28 AWG Secondary: 3T, 5 × 25 AWG T.I.W. 绕组顺序 (引脚号) Tape, Shield (2–3), Tape, Primary (4–1), Tape, Bias (6–5), Tape, Secondary (7,8,9–10,11,12), Tape 电感 Primary: 490 mH, 10% Leakage: 6 mH (maximum) 初级谐振频率 2 MHz (minimum) 40 30 20 -10 0 Quasi-Peak Scan Average Scan -10 -20 0.15 1 EN_V_QPŋ EN_V_AV 10 30 Frequency (MHz) 表1. 变压器结构信息（AWG = 美国线规，T.I.W. = 三层绝缘线） 80 70 QP Limit Line 60 PI-3005-073102 图2. 用于LCD显示器电源的115 V传导EMI，满足FCC Part 15 Class B的要求 Amplitude (dBmV) 变压器参数 AV Limit Line 50 40 30 20 -10 0 Quasi-Peak Scan -10 -20 0.15 Average Scan 1 EN_V_QPŋ EN_V_AV 10 30 Frequency (MHz) 图3. 用于LCD显示器电源的230 V传导EMI，满足EN55022 EMI标准要求 Power Integrations 5245 Hellyer Avenue San Jose, CA 95138, USA. Main: +1 408-414-9200 Customer Service Phone: +1-408-414-9665 Fax: +1-408-414-9765 Email: [email protected] Power Integrations reserves the right to make changes to its products at any time to improve reliability or manufacturability. Power Integrations does not assume any liability arising from the use of any device or circuit described herein. POWER INTEGRATIONS MAKES NO WARRANTY HEREIN AND SPECIFICALLY DISCLAIMS ALL WARRANTIES INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT OF THIRD PARTY RIGHTS. The products and applications illustrated herein (transformer construction and circuits external to the products) may be covered by one or more U.S. and foreign patents or potentially by pending U.S. and foreign patent applications assigned to Power Integrations. A complete list of Power Integrations' patents may be found at www.powerint.com. Power Integrations grants its customers a license under certain patent rights as set forth at http://www.powerint.com/ip.htm. On the Web www.powerint.com The PI logo, TOPSwitch, TinySwitch, LinkSwitch, DPA-Switch, PeakSwitch, EcoSmart, Clampless, E-Shield, Filterfuse, StackFET, PI Expert and PI FACTS are trademarks of Power Integrations, Inc. Other trademarks are property of their respective companies. ©2003, Power Integrations, Inc. C 10/08 DI-21