300w开关电源设计(图纸)

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开关电源设计及波形.ppt

开关电源设计及波形.ppt
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这类电源的共同特点是具有高 频变压器、直流稳压是从变压 器次级绕组的高频脉冲电压整 流滤波而来。变压器原副方是 隔离的,或是部分隔离的,而 输入电压是直接从交流市电整 流得到的高压直流。
传输功 率 20~ 100W
50~ 200W 100~ 500W 100~ 5000W
目前,用高频 变压器的变换 电路按其工作 方式可分为五 类,每类传输 的功率也不相 同,应用环境 也稍有不同, 如下所示:
无工频变压器开关稳压电源,有如下的优点: 1.效率高。一般在70~80%以上。 2.体积小、重量轻,随着频率的提高,收效更显著。 3.稳压范围广,一般交流输入80~265V,负载作大幅 度变化时,性能很好。 4.噪声低,声频在20kHz以上时,已是人耳听不到的 超声波,而开关电源的工作频率一般都大于此频率; 5.性能灵活,通过输出隔离变压器,可得到低压大电 流、高压小电流;一个开关控制的一路输入可得到多 路输出以及同号、反号等输出; 6.电压维持时间长,为了适应交流停电时,计算机、 现代自动化控制设备电源转换的需要,开关电源可在 几十毫秒内保证仍有电压输出。 7.可靠性大,当开关损坏时,也不会有危及负载的高 电压出现。
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300W车载逆变器电路图与原理分析.pptx

300W车载逆变器电路图与原理分析.pptx
KSP44为电话机中常用的高压三极管,当KSP44损坏而无法买到时,可用日光灯电路中常用的三极管 KSE13001进行彳弋换。KSE13001为FAlRCHl1.D公司产品,主要参数为BVCB。=400V,BVCE。 =400V,ICM=100mA,PCM=。.6W,hFE=40~80°KSE13001的封装形式虽然同样为T。-92,但其引脚电极的排序却与 KSP44不同,这一点在代换时要特殊留意。KSE13001引脚电极的识别方法是,当面对三极管的印字标识面时,其 引脚电极1为基极B、2为集电极C、3为放射极E。
SS8550为目前市场上较为常见、易购的三极管,价格也比较便宜,单只售价仅0.3元左右。
KSP44为T。・92形式封装的NPN型三极管。其引脚电极的识别方法是,当面对三极管的印字标识面时,其引 脚1为放射极E、2为基极B、3为集电极C。
KSP44的主要参数指标为:BVCB。=500V,BVCE。=400V,VCE(三)=。.5V,VBE(。N)=。 .75V,ICM=300mA,PCM=。.625W,TJ=150oC,hFE=40~2000
IRF740A为T。∙220形式封装的N沟道增加型MoS快速功率开关管。其引脚电极排序1为栅极G、2为漏极D、3为 源极S。
IRF740A的主要参数指标为:VDSS=400V,ID=I。A,Ptot=120W,RDS(。N)S55。m。
当IRF740A损坏无法买到时,可用封装形式和引脚电极排序完全相同的N沟道增加型M。S开关管IRF740B、 IRF740或IRF730进行代换。IRF740、IRF740B的主要参数与IRF740A完全相同。IRF730的主要参数为 VDSS=400V,ID=5.5A,RDS(。N)31。其中IRF730的参数虽然与IRF740系列的相比略差,但对于150W以下功率的逆 变器来说,其参数指标已经是绰绰有余了。

300w开关电源方案

300w开关电源方案

300W开关电源方案简介本文档介绍了一个300W的开关电源方案,用于提供稳定可靠的电源供应。

开关电源是一种将交流电转换为直流电的电源,通过开关管的开关动作来实现电压和电流的转换。

本方案采用了先进的电路设计和高效的开关管,以提高电源效率和稳定性。

方案设计输入电路300W开关电源的输入电压范围通常为220VAC或110VAC,本方案针对220VAC设计。

输入电路主要由滤波器、整流器和变压器组成。

滤波器用于滤除输入电压中的高频噪声,以保证输出电压的稳定性。

常见的滤波器电路包括Pi型滤波器和L型滤波器。

整流器将交流电转换为直流电,常见的整流器电路有全波整流和半波整流。

全波整流器可以实现较高的转换效率。

变压器用于将输入电压变换为适合开关电源工作的低压电压。

变压器一般由高频变压器和输出电感器组成,以提供高效的功率转换。

控制电路开关电源的控制电路主要包括开关管驱动电路和反馈控制电路。

开关管驱动电路负责控制开关管的开关动作,并控制输出电压。

常见的开关电源控制电路有固定频率PWM控制和变频控制。

反馈控制电路用于监测输出电压并调整开关管的开关动作,以稳定输出电压。

反馈控制电路一般由比较器、误差放大器和反馈元件组成。

输出电路输出电路主要由输出电感器、输出电容和负载组成。

输出电感器用于平滑输出电流,防止电流突变。

输出电容则用于平滑输出电压,提供稳定的负载。

负载是指连接在开关电源输出端的设备或电路,可以是各种电子设备、通信设备或其他电子装置。

负载的功率需小于或等于300W。

优点与特点高效率300W开关电源采用了高效率的开关管和控制电路,以减少功耗并提高转换效率。

高效率意味着更少的能量损耗,更低的温度和更长的使用寿命。

稳定性本方案采用了反馈控制电路来稳定输出电压,同时使用优质的电子元件和合理的电路布局,以提供稳定可靠的电源供应。

稳定的输出电压对各种设备和电路的正常运行至关重要。

可靠性300W开关电源采用了与国际标准相符的设计和制造工艺,确保产品的质量和可靠性。

超详细的反激式开关电源电路图讲解

超详细的反激式开关电源电路图讲解

反激式开关电源电路图讲解一,先分类开关电源的拓扑结构按照功率大小的分类如下:10W以内常用RCC(自激振荡)拓扑方式10W-100W以内常用反激式拓扑(75W以上电源有PF值要求)100W-300W 正激、双管反激、准谐振300W-500W 准谐振、双管正激、半桥等500W-2000W 双管正激、半桥、全桥2000W以上全桥二,重点在开关电源市场中,400W以下的电源大约占了市场的70-80%,而其中反激式电源又占大部分,几乎常见的消费类产品全是反激式电源。

优点:成本低,外围元件少,低耗能,适用于宽电压范围输入,可多组输出.缺点:输出纹波比较大。

(输出加低内阻滤波电容或加LC噪声滤波器可以改善)今天以最常用的反激开关电源的设计流程及元器件的选择方法为例。

给大家讲解如何读懂反激开关电源电路图!三,画框图一般来说,总的来分按变压器初测部分和次侧部分来说明。

开关电源的电路包括以下几个主要组成部分,如图1图1,反激开关电源框图四,原理图图2是反激式开关电源的原理图,就是在图1框图的基础上,对各个部分进行详细的设计,当然,这些设计都是按照一定步骤进行的。

下面会根据这个原理图进行各个部分的设计说明。

图2 典型反激开关电源原理图五,保险管图3 保险管先认识一下电源的安规元件—保险管如图3。

作用:安全防护。

在电源出现异常时,为了保护核心器件不受到损坏。

技术参数:额定电压 ,额定电流 ,熔断时间。

分类:快断、慢断、常规计算公式:其中:Po:输出功率η效率:(设计的评估值)Vinmin :最小的输入电压2:为经验值,在实际应用中,保险管的取值范围是理论值的1.5~3倍。

0.98: PF值六,NTC和MOVNTC 热敏电阻的位置如图4。

图4 NTC热敏电阻图4中的RT为NTC,电阻值随温度升高而降低,抑制开机时产生的浪涌电压形成的浪涌电流。

图4中RV为MOV压敏电阻,压敏电阻是一种限压型保护器件,过电压保护、防雷、抑制浪涌电流、吸收尖峰脉冲、限幅、高压灭弧、消噪、保护半导体元器件等七,XY电容图5 X和Y电容如图X电容,Y电容。

300w开关电源方案

300w开关电源方案

300W开关电源方案概述本文档将介绍一种可以提供300W输出功率的开关电源方案。

开关电源是一种能够将输入电压转换为稳定输出电压的电源装置。

它使用开关器件(通常是晶体管或MOSFET)来控制输入电压的开关行为,从而实现调整输出电压的目的。

系统设计输入电路开关电源的输入端通常需要接受来自电网的交流(AC)电压。

为了适应不同的输入电压范围,我们将采用变压器和整流桥的组合。

变压器可以将电网提供的高电压降低为适当的中间电压,整流桥则将交流电转换为直流电。

滤波电路直流输出的电压经过整流后,仍然存在一些纹波和噪声。

为了降低这些干扰,我们需要设计一个滤波电路。

常用的滤波电路包括电容滤波和电感滤波。

电容滤波器通常用于去除高频噪声,而电感滤波器则用于去除低频纹波。

锁相环(PLL)为了确保开关频率稳定且与输入电压同步,我们将使用一种称为锁相环(Phase-Locked Loop,PLL)的技术。

PLL通过比较输入信号和参考信号的相位差,并调整输出信号的频率,从而使两者保持同步。

这将确保开关器件以恰当的时机开关,从而实现输出电压的稳定。

控制器开关电源的控制器负责监测和调整输出电压。

它通常由一个微处理器或专用的控制芯片实现。

控制器通过测量输出电压并与参考电压进行比较,控制开关器件的开关频率和占空比,以保持稳定的输出。

开关器件开关器件是实现开关电源功能的核心组件。

常见的开关器件包括晶体管、场效应晶体管(MOSFET)和双极性晶体管(BJT)。

它们通过开关行为控制输出电压。

选择适当的开关器件非常重要,因为它们的开关速度、功耗和可靠性等特性将直接影响到整个系统的性能。

反馈回路为了实现输出电压的稳定性,我们将使用反馈回路。

反馈回路通过将一部分输出电压引导回控制器,并与参考电压进行比较来调整开关行为。

采用合适的反馈网络设计可以实现很高的输出稳定性和响应速度。

性能参数输出功率:300W本方案设计的开关电源具有300W的输出功率,可以满足大多数低功率应用的需求。

反激式开关电源设计详解

反激式开关电源设计详解

压敏电阻的作用
• 压敏电阻是一种限压型保护器件。利用压敏电阻的非线性 特性,当过电压出现在压敏电阻的两极间时,压敏电阻可 以将电压钳位到一个相对固定的电压值,从而实现对后级 电路的保护。 • 主要作用:过电压保护、防雷、抑制浪涌电流、吸收尖峰 脉冲、限幅、高压灭弧、消噪、保护半导体元器件等。 • 主要参数有:压敏电压、通流容量、结电容、响应时间等。 • 压敏电阻的响应时间为ns级,比空气放电管快,比TVS 管(瞬间抑制二极管)稍慢一些,一般情况下用于电子电 路的过电压保护,其响应速度可以满足电路要求。
选取压敏电阻的方法
• 结合前面所述,来看一下本电路中压敏电 阻的型号所对应的相关参数。
EMI电路
• X电容,共模电感(也叫共模扼流圈 ),Y 电容
– 根据IEC 60384-14,安规电容器分为X电容及Y 电容:
• 1. X电容是指跨与L-N之间的电容器, • 2. Y电容是指跨与L-G/N-G之间的电容器.
相关知识
关于功率因数
• 大部分用电设备,其工作电压直接取自交流电网。 所以电网中会有许多家用电器、工业电子设备等 非线性负载,这些用电器在使用过程中会使电网 产生谐波电压和电流。没有采取功率因数校正技 术的AC-DC整流电路,输入电流波形呈尖脉冲状。 交流网侧功率因数只有0.5~0.7,电流的总谐波畸 变(THD)很大,可超过100%。采用功率因数校 正技术后,功率因数值为0.999时,THD约为3%。 为了防止电网的谐波污染,或限制电子设备向电 网发射谐波电流,国际上已经制定了许多电磁兼 容标准,如IEEE519、IEC1000-3-2等。
反激开关电源特点
• 在开关电源市场中,400W以下的电源大约占了市 场的70-80%,而其中反激式电源又占大部分,几乎 常见的消费类产品全是反激式电源。 优点:成本低,外围元件少,低耗能,适用于宽电 压范围输入,可多组输出. 缺点:输出纹波比较大。(输出加低内阻滤波电容 或加LC噪声滤波器可以改善) • 今天以自行车充电器为例,详细讲解反激开关电 源的设计流程及元器件的选择方法。

300W单相逆变电源的设计与实现

300W单相逆变电源的设计与实现

第18卷 第4期Vol 118 No 14北京印刷学院学报Journal of Beijing I nstitute of Graphic Communicati on 2010年8月Aug 12010 收稿日期:2010202210基金项目:北京市教委资助项目(K M200910015012);北京市属高等学校人才强教计划资助项目300W 单相逆变电源的设计与实现续明进(北京印刷学院,北京 102600)摘 要:设计了一种单相交流逆变电源装置,主要包括低压直流升压斩波电路和单相桥式逆变电路。

给出了主电路参数和控制电路设计方法。

实验结果表明,该电源具有输出稳定、效率高、成本低等优点,达到了设计要求。

关键词:逆变器;升压斩波;SP WM 中图分类号:T N86文献标识码:A文章编号:100428626(2010)0420053203The D esi gn of 300W S i n gle 2Pha seI nverter Power SupplyXU M ing 2jin(Beijng I nstitute of Graphic Communicati on,Beijing 102600,China )Abstract:The design of a single 2phase inverter power supp ly is p resented in the paper,the syste m consists of the DC step up chopper and single 2phase full 2bridge inverter .The contr ol system and para meter design are intr oduced .The experi m ental results verify that the power supp ly has merits of highly accu 2rate steady out put,high efficiency,and l ow cost .Key words:inverter;step up chopper;SP WM在小功率的光伏发电系统与风力发电系统、车载电源等多种应用场合中,蓄电池作为主要的装置,起到电能的储存作用,并能连续平稳地向负载供电。

最新整理300系列装置典型图册(cad版本)

最新整理300系列装置典型图册(cad版本)
注 :MBZT-310Hb DC220V 5ART18-32/6AAD11-25/40 DC220V型 号 及 规 格设 备 表3序号1245687备用电源自投自复装置装置母线分段保护装置绿灯 红灯名 称HG,HR符 号SA控制开关FBZBZT1FU~4FU1XB~3XB连接片熔断器YY1-D备 注套套个个单位2数量111个个34BZT(MBZT-310Hb)带电显示装置闭锁备自投接点入输58BS93344459319272DD1DD5756自产+24V1#进线辅助接点2#进线辅助接点分段开关辅助接点量关开925923QF2QF55549219191QF5253号80797877回合2#进线2QF路跳2#进线2QF制控7374757240741器路闭锁输出接点断39737317337292930731备自投动作电流保护动作信 地 信号公共端就MLPR-310Hb-3 DC220V 5A2412132112332TAL3V6301513U630WVIL1WVIL21TAL31TAL21TAL114FBZ(MLPR-310Hb-3)WVIn17W630WVIL319N600L630WVIL0测 量20路回压电6245103121N421W421811回路保护电流测量电流FBZ(MLPR-310Hb-3)流电10(35)kV母线 段1QF2TAL22TAL12QFQFGV421U421791TV2TV一次接线示意图10(35)kV母线 段V640电源自投自复装置交流输入回路图35kV变电所微机保护二次通用设计W640MBZT-310Hb-1/4MBZT-310Hb微机型2018路U640W630V630U630BZT(MBZT-310Hb)171614回压电13路1#进线电流回42流电1618分段或母联开关控制回路图MBZT-310Hb-2/4MBZT-310Hb微机型电源自投自复装置信号回

300W电源方框图和原理

300W电源方框图和原理

Two ‐Switch Forward Converter for PC Power Supply1. Block Diagram+5Vsb+12V+5V+3.3V‐12VFunctional Block Diagram (Hasek)2. Circuit Description2.1 AC power input circuit is as below.EMI filter : AC power line is connected to L, N, FG terminal, EMI Filter is organized by CY1, CY2, CX1, CY3, CY4, CX2, LF1 and LF2 to filter out EMI noise.PFC corrector: PFC‐1 and PFC‐2 choke are connected between EMI filter and Bridge diode used to improve the power factor PSU.Rectifier: Bridge diode and capacitor C1 and C2 are used to rectify and filter input AC voltage to DC voltage.Voltage Doubler: When input voltage is 115Vac, SW is turned on to get two time DC voltage on DC bus.2.2 DC/DC PWM converter circuitThe UC3845 family of control ICs provides the necessary features to implement DC to DC fixed frequency current mode control schemes, a precision reference trimmed for accuracy at the error amplifier input, a PWM comparator which also provides current limit control, and a totem pole output stage designed to source or sink high peak current. A range of the zero to < 50 % duty cycle is obtained by the UC3845 by the addition of an internal toggle flip flop which blanks the output off every other clock cycle. T3 is the pulse transformer coupling the PWM driver signal to dual forward MOSFET gate."2.3 Multi‐output circuitA magamp saturable core L2 is used to regulate 3.3V, error amplifier U6 is used to detect theoutput voltage of 3.3V rail, the error voltage between output voltage and reference voltage is used to control Q4 current Ic, Ic current is used to reset the flux density of L2 to control the magamp conduction delay time to regulate the output voltage.2.3.1 Multi‐Output Using Coupled Choke design2.3.2 ‐12V railA linear voltage regulator IC L7912 is used to control ‐12V rail output voltage.The “Magic Turn Ratio”, 7:3 is selected for +12V and +5V outputs, which could result in better load regulation. However, it is difficult to regulate +3.3V with the same technology. Thus, a magnetic amplifier circuit us adopted for +3.3V channel with its independent feedback network.Stacking +12V winding on the top of +5V winding (operates like a autotransformer) could be cost effective. Also, a coupled‐inductor is used for better coupling on +12V and +5V channels.3. Fan control circuitThermistor NTC TH2 is put on the heat sink to detect the temperature of power device, when temperature is increased, the resistance of thermistor is decreased, and the error amplifier U5A decreases output voltage to increase Q7 current and makes fan speed increased; Zener ZD6 is used to limit the minimum fan voltage or speed.4. Housekeeping circuitHousekeeping circuit includes OVP, OCP, UVP function of +3.3V, +5V and +12V rail, it also has OVP and SCP of ‐12Vrail, it provide latch off function for malfunction condition.IC WT‐7505 is used for this design.5. Standby powerStandby power adopts flyback circuit, control IC is Tiny‐Switch‐III incorporates a 700 V power MOSFET, oscillator, high voltage switched current source, current limit (user selectable) and thermal shutdown circuitry. The IC uses an ON/OFF control scheme and offers a design flexiblesolution.。

超详细的反激式开关电源电路图讲解

超详细的反激式开关电源电路图讲解

超详细的反激式开关电源电路图讲解反激式开关电源电路图讲解一,先分类开关电源的拓扑结构按照功率大小的分类如下:10W以内常用RCC(自激振荡)拓扑方式10W-100W以内常用反激式拓扑(75W以上电源有PF值要求)100W-300W 正激、双管反激、准谐振300W-500W 准谐振、双管正激、半桥等500W-2000W 双管正激、半桥、全桥2000W以上全桥二,重点在开关电源市场中,400W以下的电源大约占了市场的70-80%,而其中反激式电源又占大部分,几乎常见的消费类产品全是反激式电源。

优点:成本低,外围元件少,低耗能,适用于宽电压范围输入,可多组输出.缺点:输出纹波比较大。

(输出加低内阻滤波电容或加LC噪声滤波器可以改善)今天以最常用的反激开关电源的设计流程及元器件的选择方法为例。

给大家讲解如何读懂反激开关电源电路图!三,画框图一般来说,总的来分按变压器初测部分和次侧部分来说明。

开关电源的电路包括以下几个主要组成部分,如图1图1,反激开关电源框图四,原理图图2是反激式开关电源的原理图,就是在图1框图的基础上,对各个部分进行详细的设计,当然,这些设计都是按照一定步骤进行的。

下面会根据这个原理图进行各个部分的设计说明。

图2 典型反激开关电源原理图五,保险管图3 保险管先认识一下电源的安规元件—保险管如图3。

作用:安全防护。

在电源出现异常时,为了保护核心器件不受到损坏。

技术参数:额定电压 ,额定电流 ,熔断时间。

分类:快断、慢断、常规计算公式:其中:Po:输出功率η效率:(设计的评估值)Vinmin :最小的输入电压2:为经验值,在实际应用中,保险管的取值范围是理论值的1.5~3倍。

0.98: PF值六,NTC和MOVNTC 热敏电阻的位置如图4。

图4 NTC热敏电阻图4中的RT为NTC,电阻值随温度升高而降低,抑制开机时产生的浪涌电压形成的浪涌电流。

图4中RV为MOV压敏电阻,压敏电阻是一种限压型保护器件,过电压保护、防雷、抑制浪涌电流、吸收尖峰脉冲、限幅、高压灭弧、消噪、保护半导体元器件等七,XY电容图5 X和Y电容如图X电容,Y电容。

四款300W音频功放电路图详解

四款300W音频功放电路图详解

四款300W音频功放电路图详解一.300W音频功放电路图选用MJL4281A(NPN)和MJL4302A(PNP),具有高带宽,良好的SOA(安全工作区),高线性和高增益。

驱动晶体管选用MJE15034(NPN)和MJE15035(PNP)。

所有器件的额定电压为350V。

输出三极管选用MJL4281A(NPN)和MJL4302A(PNP),具有高带宽,良好的SOA(安全工作区),高线性和高增益。

驱动晶体管选用MJE15034(NPN)和MJE15035(PNP)。

所有器件的额定电压为350V。

性能指标:8Ω4Ω电压增益27dB27dB功率(连续)153W (240W)240W (470W)峰值功率 - 10 ms185W (250W)344W (512W)峰值功率 - 5 ms185W (272W)370W (540W)输入电压1.3V (2.0V)RMS1.3V (2.0V) RMS噪声 *-63dBV (ref. 1V)-63dBV (ref. 1V)S / N比 *92dB92dB失真0.4%0.4%失真(@ 4W)0.04% (1 Khz)0.04% (1 Khz)失真(@ 4W)0.07% (10 kHz)0.07% (10 kHz)摆率》 3V/us》 3V/us300W音频功率放大器电路原理图300W音频功率放大器电源线路图二.由STK3152Ⅲ组成的300W功放电路前置放大电路信号输入采用平衡与不平衡两种方式,平衡输入电路由运放NE5532及外围电路组成,不平衡输入直接送人STK3152Ⅲ的1脚和15脚,经STK3152Ⅲ放大后的信号分别由5、6、10、11脚输出,2、14脚分别为两个声道的负反馈输入端NF。

电源电路功率放大电路每声道采用了8对日本东芝生产的发烧级大功率对管,以保证足够的电流驱动能力。

制作时也可根据实际需要选取合适的功率管数量。

图8对应的印板图见图9。

由于工作电流较大,整流滤波部分没有采用印板,而是采用直接搭焊的形式。

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TND313/DRev 3, Sep-11High-Efficiency305 W ATX Reference Design Documentation Package© 2011 ON Semiconductor.Disclaimer: ON Semiconductor is providing this reference design documentation package “AS IS” and the recipient assumes all risk associated with the use and/or commercialization of this design package. No licenses to ON Semiconductor’s or any third party’s Intellectual Property is conveyed by the transfer of this documentation. This reference design documentation package is provided only to assist the customers in evaluation and feasibility assessment of the reference design. The design intent is to demonstrate that efficiencies beyond 80% are achievable cost effectively utilizing ON Semiconductor provided ICs and discrete components in conjunction with other inexpensive components. It is expected that users may make further refinements to meet specific performance goals.Table of Contents1.Overview (6)2.Specifications (7)3.Architecture Overview (8)4.Performance Results (13)5.Evaluation Guidelines (23)6.Schematics (24)7.Parts List (29)8.Critical Component Information (35)9.Resources/Contact Information (35)10.Appendix (36)List of TablesTable 1: Target Specifications (7)Table 2: Load matrix for efficiency measurements (13)Table 3: Load matrix for cross regulation measurements (15)Table 4: Transient load conditions (18)List of FiguresFigure 1: Reference Design Architecture Block Diagram (7)Figure 2: One switch forward topology and associated waveform (9)Figure 3: Active clamp forward topology and associated waveform (11)Figure 4: Efficiency vs percentage load from 20% to full load (13)Figure 5: Power factor vs percentage load (14)Figure 6: Efficiency vs percentage load from 5% to full load (14)Figure 7: 5 V and 5 V SBY outputs cross regulation vs load conditions (16)Figure 8: 3.3 V output cross regulation vs load conditions (16)Figure 9: 12 V1 and 12 V2 outputs cross regulation vs load conditions (17)Figure 10: -12 V output cross regulation vs load conditions (17)Figure 11: 5 V output transient load response (18)Figure 12: 12 V1 output transient load response (18)Figure 13: 12 V2 output transient load response (19)Figure 14: 3.3 V output transient load response (19)Figure 15: 5 V output voltage ripple at full load (20)Figure 16: 3.3 V output voltage ripple at full load (20)Figure 17: 12 V1 output voltage ripple at full load (20)Figure 18: 12 V2 output voltage ripple at full load (21)Figure 19: -12 V output voltage ripple at full load (21)Figure 20: 5 V SBY output voltage ripple at full load (21)Figure 21: Holdup time at full load (22)Figure 22: Input inrush current (22)Figure 23: ATX solution boards in ATX enclosure (24)Figure 24: PFC controller PCB board schematic (25)Figure 25: EMC component board (25)Figure 26: Active clamp controller PCB board schematic (26)Figure 27: Supervisory and 3.3 V post regulator controller PCB board schematic (27)Figure 28: Main PCB board schematic PFC and standby section (27)Figure 29: Main PCB board schematic active clamp stage section (28)Figure 30: Main PCB board schematic 3.3 V post regulator section (28)1. OverviewON Semiconductor was the first Semiconductor company to provide an 80 PLUS open reference design for an ATX Power Supply in 2005. This 1st generation reference design, was certified and met all the requirements of the 80 PLUS program. Following on this successful 1st generation design, ON Semiconductor is introducing its improved 2nd Generation reference design. This 2nd generation design utilizes newer ICs from ON Semiconductor that enable this design to exceed 80% efficiency starting at 20% load across different line conditions with ample margin to spare.This reference document provides the details behind this 2nd generation design. The design manual provides a detailed view of the performance achieved with this design in terms of efficiency, performance, thermals and other key parameters. In addition, a detailed list of the bill-of-materials (BOM) is also provided. ON Semiconductor will also be able to provide technical support to help our customers design and manufacture a similar ATX power supply customized to meet their specific requirements.The results achieved in this 2nd generation design were possible due to the use of advanced new components from ON Semiconductor. These new ICs not only speeded up the overall development cycle for this new design, but also helped achieve the high efficiencies while at the same time keeping a check on the overall cost. With the use of these new ICs, ON Semiconductor has proven again that the emerging requirements for high efficiency desktop power supplies can be met and further, can be optimized to meet specific performance vs. cost goals.This 2nd generation design consists of a single PCB designed to fit into the standard ATX enclosure along with a fan. Figure 1 below presents the overall architecture employed in this design – detailed schematics are included later in this design manual. As seen in figure 1, this design employed an Active Clamp forward topology using the new, highly integrated Active Clamp Controller IC from ON Semiconductor – NCP1562. A Continuous Conduction Mode (CCM) Power Factor Correction (PFC) IC was employed for the active PFC circuit. This IC, the NCP1653 provides an integrated, robust and cost-effective PFC solution. The standby controller, NCP1027, is an optimized IC for the ATX power supply and incorporates a high-voltage MOSFET. On the secondary side, this architecture employs a post regulator approach for generating the 3.3 V output. This is an alternative approach to the traditional magnetic amplifier (Mag Amp) approach. Though ON Semiconductor believes that this post regulator approach provides the highest efficiency amongst the different means of generating these outputs in the power supply, it is important to note that if the customer desires to use a different approach, that is possible – i.e. a similar design can be developed that utilizes all the other pieces of this architecture without the post regulator and still achieve very good results.With the introduction of this 2nd generation, high-efficiency ATX Power Supply, ON Semiconductor has shown that with judicious choice of design tradeoffs, optimum performance is achieved at minimum cost.Figure 1: Reference Design Architecture Block Diagram2. SpecificationsThe design closely follows the ATX12V version 2.2 power supply guidelines and specifications available from , unless otherwise noted. For instance, our reference design had a target of +/- 5% tolerance for both the 5 V and 5 Vstandby outputs. Further, the efficiency targets for the 80 PLUS program and the EPA’s Energy Star specification – Energy Star Program Requirements for Computers, version 4.0 that is set to take effect from July 20, 2007 – were targeted. Key specifications are included in Table 1 below.Output Current Tolerance (%) Ripple/Noise(mV) Min. (A) Max (A)5 V 0.3 22 ± 3.350 5 V standby 0.0 2.5 ± 3.350 12 V 1.0 18 ± 5.0120 - 12 V 0.0 1 ± 10120 Table 1: Target SpecificationsTarget specifications for other key parameters of the reference design include: -Efficiency: Minimum efficiency of 80% for 20%, 50% and 100% of rated output load conditions as defined by the 80 PLUS requirements as well as the Energy Star specification.-Power Factor: Power factor of 0.9 or greater at 100 % load.-Input Voltage: Universal Mains – 90 Vac to 265 Vac, 47 – 63 M Hz.-Output Power: Total maximum output power is 305 W.-Safety Features: As per the ATX12V specification, this design includes safety features such as OVP, UVP, and OCP.-This design meets the IEC1000-3-2 requirements over the input line range and under full load conditions.-This converter was designed for a 20 ms minimum Hold-up time.-Physical dimensions: This converter is designed to fit into the standard ATX enclosure with dimensions of 150 mm x 140 mm x 86 mm.3. Architecture OverviewBefore discussing the power supply architecture of the Generation 2 design, it is worth reiterating the design goals. We are tasked with providing a flexible power platform, which is required to have the lowest cost and highest efficiency that can be packaged in a small volume. The architecture must deliver a minimum of 80% efficiency over a wide range of operating conditions (high-line and low-line) as well as rated output load conditions (20% load and above). In addition we require a robust design solution having low parts count to provide the same performance on a unit to unit basis in a high volume manufacturing environment.The architecture selected follows a traditional two stage conversion approach as illustrated in Figure 1. It is worth noting that in order to achieve 80% efficiency overall, the efficiency of each of the two conversion stages must exceed 90 %. The front-end is a universal input, active power factor boost stage delivering a constant output voltage of 385 V to the active clamp stage. The second stage consists of two, dc-dc converters. The first down-stream converter processes 290 W required by the system in the form of tightly regulated +/-12 V, +5 V and +3.3 V outputs. The second converter delivers 15 W of standby power to another isolated 5 V rail.ON Semiconductor has developed multiple power management controllers and MOSFET devices in support of the ATX program. Web based data sheets, design tools and technical resources are available to assist design optimization. The ICs, supporting the ATX Generation 2 platform, are the NCP1653 PFC controller, the NCP1562 active clamp controller, the NCP4330 post regulator, the NCP1027 standby controller, and the NTP48xx family of MOSFET synchronous rectifiers. It is not possible to discuss the tradeoffs involved in each conversion stage at length, but the selection of the activeclamp forward converter topology is a key one and will be covered in depth. Each controller is highly integrated and offers the lowest external parts count available.PFC StageThere are a variety of PFC topologies available. These include discontinuous conduction mode (DCM), critical conduction mode (CRM) and continuous conduction mode (CCM). At this power level, CCM is the preferred choice and the NCP1653 will implement a IEC1000-3-2 compliant, fixed frequency, peak current mode PFC boost converter with very few external components.DC to DC (Main) ConverterThe selection of the dc-dc down stream converter is at the heart of the 80% solution. The traditional work horse of the ATX market has been the single switch forward converter operating at a switching frequency of 100 kHz. The converter and its associated drain waveform are illustrated in Figure 2. This topology is robust and delivers good full load efficiency performance at minimal cost. However, as power levels increase and regulatory requirements and energy conservation agencies drive for higher efficiency under all load conditions, the single switch forward topology in its simplest form is reaching its limit.Figure 2: One switch forward topology and associated waveformThere are several technical reasons for this. First, because the main transformer is reset via an auxiliary winding across the input bus, the duty cycle is limited below 50%. Second, because of this reset mechanism there is always a dead time interval, during each converter cycle, when no power is flowing. These two constraints have negative implications on the silicon utilization of the primary switch requiring a costly, large area die to be selected. The primary switch’s conduction loss is given by (1))(*2*)(on DS R P I D conduction loss P =(1)where, D is the duty cycle, I P is the primary current and R DS(on) is the switch on resistance. The topology is a hard switched topology with the primary switch being driven on with 385 V across it each switching cycle. The capacitive switch loss are given by (2),f DS V OSS C capacitive loss P *2*21)(= (2)where, C OSS is the switch output capacitance, V DS is the drain to source voltage and f is the operating frequency. Capacitive losses dominate at light load. Hence a switch selected for full load performance will suffer at light load because of its large drain source capacitance. Reviewing these two loss equations, it becomes apparent for efficiency enhancement under both full load and light load operation, a topology is required that allows the primary switch to operate at lower current and voltage stress. As the loss terms appear as current and voltage squared, small reductions in primary current I P and switch voltage V DS significantly improve performance.The active clamp forward converter illustrated in Figure 3 represents the ultimate extension of the single switch converter and provides these benefits. Instead of using an auxiliary winding, transformer reset is achieved using a clamp capacitor and an auxiliary switch. The reset period, controlled by the auxiliary switch now extends to the interval ()S T D *1−, completely eliminating the previous dead time interval. To maintain flux balance in the main transformer core, the reset voltage across the clamp capacitor isdetermined by the expression ()D D in V −1*. The duty cycle D of the single switch forwardconverter can extend beyond 50%, limited only by the primary switch’s maximum voltage rating.Figure 3: Active clamp forward topology and associated waveformFor a given set of conditions and power throughput, operating at extended duty cycles allows for a lower primary current. This in turn allows the selection of a smaller, lower cost die. Let’s look at a design example to illustrate this point.To reduce cost, a 150 μF bulk capacitor (instead of a 470 μF conventional value) is selected to provide 20 ms of hold up time. Using the energy storage equation given by (3),()ηtime up Hold Delivered Power V V C Energy f i **2122=−= (3)where, V i and V f are the initial and final voltages of the input capacitor, respectively. The initial voltage is 385 V and converter efficiency is 90%, allows us to calculate the final voltage V f to be 250 V. In the case of a conventional single switch design, the maximum duty cycle we can practically select and avoid transformer saturation is 0.45. The switch voltage stress is 2 x 250 V. With the active clamp single switch forward, the duty cycle can be extended to 0.67 and the voltage stress on the switch is Vin / (1-D) or 3.03 x 250 V. Each converter has to process 290 / 0.9 or 322 W from the primary bulk source. At nominal 385 V bulk, the average primary current is 0.84 A. Factoring in the primary switch duty cycle D, the peak current I P in the traditional forward converter is 0.65 / 0.45 or 1.44 times larger than the active clamp approach. Based on the conduction loss equation given by (1), we see that the 1.44 ratio holds true for conduction loss in the primary switch. Put another way, we can choose a MOSFET with 44% higher R DS(on) in the active clamp topology and have the same conduction loss. This is significant, as we can achieve better silicon utilization, lower cost and lower drain capacitance. By reviewing the data sheets from high voltage MOSFET vendors, it is possible to compare output capacitance C OSS versus R DS(on) as a function of die size. For example as MOSFET resistance increases from 3.6 Ω to 4.8 Ω, the output capacitance reduces from100 pF to 70 pF. The resonant nature of the active clamp allows the switch be turned on at 300 V instead of the conventional 400 V. These two effects allow a reduction in capacitive switching loss of 39% over a conventional design. Again, a significant improvement remembering that light load efficiency is determined predominately by switching loss. The example above illustrates how small changes in switch stress can impact overall cost and performance.The same argument relating to increased duty cycle operation extends to the secondary by proportionally reducing output rectifier loss. Since the secondary loss is a dominant factor at full load, an additional efficiency improvement/ cost benefit is realized. To achieve the ultimate efficiency, synchronous rectification is required on the +12 V and +5 V outputs. The single switch active clamp forward is very suitable to drive synchronous rectifiers directly from the secondary windings without the need for expensive gate drivers or additional delay timing circuitry.To allow designers to capitalize on the benefits inherent in the active clamp topology, the NCP1562 has been developed to capture all the necessary control features within a 16 pin package. The full featured controller has been designed for tight tolerance on all parameters, including the maximum duty cycle limit and the important soft stop function. To boost efficiency and maintain tight regulation, instead of the conventional magnetic amplifier post regulated approach, the 3.3 V output is derived from the 5 Volt winding of the main transformer. The MOSFET drivers, timing, synchronization and control functions to support this output are provided by the NCP4330 controller. A 6 W improvement in the loss budget is achieved when this approach is adopted. Gate charge and R DS(on) have been optimized in the NTP48xx family of MOSFETs and provide synchronous rectification for both the 3.3 V and 5 V outputs.Standby PowerThe NCP1027 integrates a fixed frequency current mode controller and a 700 volt MOSFET. The NCP1027 is an ideal part to implement a flyback topology delivering 15 W to an isolated 5 V output. At light loads the IC will operate in skip cycle mode, thereby reducing its switching losses and delivering high efficiency throughout the load range.4. Performance ResultsThe evaluation of the reference design focused on several areas including efficiency, power factor, cross regulation and transient load response. Design optimizations may be needed to customize this reference design to meet specific requirements.The converter efficiency is measured according to the operating conditions detailed in Table 2. The converter efficiency is measured at 100 Vac, 115 Vac and 230 Vac at 50 Hz. The converter achieves over 80% efficiency with room to spare over all load conditions as shown in Figure 4. The output voltages used for the efficiency calculations are measured at the end of the power cables. The fan is disabled for measurements at or below 20% load. The fan is automatically enabled once the load exceeds 60 W or 20%. The fan is operational for 50% and 100% load measurements. Further increases in the efficiency can be obtained for 50% and 100% load conditions through fan speed control.Load Condition Output Current (A) 5 V 3.3 V 12 V1 12 V2 -12V5 V SBY 5 % 0.690 0.540 0.385 0.385 0.030 0.070 10 % 1.390 1.070 0.770 0.770 0.070 1.390 15 % 2.080 1.610 1.150 1.150 0.100 0.210 20 % 2.7802.150 1.510 1.510 0.140 0.280 50 % 6.950 5.3703.845 3.845 0.350 0.700 100 %13.900 10.7407.695 7.6950.700 1.400Figure 4: Efficiency vs percentage load from 20% to full loadThe power factor exceeds 0.9 over all operating conditions as shown in Figure 5.Figure 5: Power factor vs percentage loadIn Figure 6, the efficiency measurements are shown from 5% load to full-load. Note that neither the 80 PLUS program nor the Energy Star specification require efficiencies above 80% for any output load below 20%. However, as can be seen in Figure 6, this reference design achieved 80% efficiency down to 16 % load.Figure 6: Efficiency vs percentage load from 5% to full loadOutput voltage cross regulation is measured according to the load conditions listed in Table 3. The results of the cross regulation measurements are shown inFigure 7 through Figure 10. Included in these figures are the tolerance requirements based on the target specifications listed in Table 1. The margin for the 5 V and 5 V SBY outputs can be increased by shifting up the regulation target for the 5 V outputs. It can also be improved by changing the weight of the 12 V and 5 V outputs in the regulation circuit.Load ConditionOutput Current (A)5 V(+/-3.3%)3.3 V(+/-4%)12 V1(+/-5%)12 V2(+/-5%)-12 V(+/-10%)5 V SBY(+/-3.3%)1 0.3 0.3 0 0 0 02 73 2 2 0.1 0.53 0.3 0.3 0 0 0 0.54 0.3 3 2 2 0.1 0.55 7 0.3 2 2 0.1 0.56 4 0.3 1 1 0.2 0.27 18 12 5 5 1 2.58 18 12 1 1 0.2 2.59 4 12 5 5 1 2.510 18 0.3 5 5 1 2.511 4 0.2 1 1 0.2 0.212 14 17 8 6 1 2.513 18 17 1 1 0.2 2.514 4 17 8 6 1 2.515 18 0.3 8 6 1 2.516 4 2 5 5 0.2 117 22 17 5 5 1 2.518 4 17 5 5 1 2.519 22 2 5 5 1 2.5Table 3: Load matrix for cross regulation measurementsFigure 7: 5 V and 5 V SBY outputs cross regulation vs load conditionsFigure 8: 3.3 V output cross regulation vs load conditionsFigure 9: 12 V1 and 12 V2 outputs cross regulation vs load conditionsFigure 10: -12 V output cross regulation vs load conditionsThe 5 V, 12 V and 3.3 V outputs are evaluated independently under transient load conditions. Each output is loaded at 50% and the load is reduced to 25% or increased to 75% of the maximum rated current. The transient voltage tolerance of each of the 5 V, 12 V and 3.3 V outputs is +/- 5%. Table 4 summarizes the transient load conditions and limits for each output. Transient waveforms are shown in Figure 11 through Figure 14.Output Minimum Load (A)Nominal Load (A)Maximum Load (A)Voltage under/overshoot (V) 5 V 5.5 11 16.5 ±250mV, ≤0.5V pk-pk 3.3 V 4.25 8.5 12.75 ±170mV, ≤0.34V pk-pk 12 V1 4.5 9 13.5 ±600mV, ≤1.2V pk-pk 12 V24.5913.5±600mV, ≤1.2V pk-pkTable 4: Transient load conditionsFigure 11: 5 V output transient load responseFigure 12: 12 V1 output transient load responseΔI LOAD = 11.5 A to 5.5 AΔI LOAD = 11.5 A to 16.5 AΔI LOAD = 9 A to 4.5 AΔI LOAD = 9 A to 13.5 AFigure 13: 12 V2 output transient load responseFigure 14: 3.3 V output transient load responseAll the outputs meet the transient voltage requirements under the evaluated conditions. The ripple voltage of each output is measured at the maximum load for each output. The output ripple is measured across 10 μF/MLC parallel 1000 μF low ESR/ESL termination capacitors. The target ripple is +/- 120 mV for the 12 V outputs and 50 mV for all other outputs. Figure 15 through Figure 20 show the output voltage ripple measurements. All outputs meet the voltage ripple requirements.ΔI LOAD = 9 A to 4.5 AΔI LOAD = 9 A to 13.5 AΔI LOAD = 8.5 A to 4.25 AΔI LOAD = 8.5 A to 12.75 AFigure 15: 5 V output voltage ripple at full loadFigure 16: 3.3 V output voltage ripple at full loadFigure 17: 12 V1 output voltage ripple at full loadFigure 18: 12 V2 output voltage ripple at full loadFigure 19: -12 V output voltage ripple at full loadFigure 20: 5 V SBY output voltage ripple at full loadThe required holdup time at full load is 20 ms. Holdup time is measured from the moment the AC power is removed to when the PWR_OK signal goes low. Figure 21 shows the holdup time at full load. Channel 1 is the AC power and Channel 2 is the PWR_OK signal. Holdup time is measured at 22.5 ms.Figure 21: Holdup time at full loadThe input inrush current of the system at 230 Vac at full load is measured at 28.8 A as shown in Figure 22.Figure 22: Input inrush current5. Evaluation GuidelinesEvaluation of the reference design should be attempted only by persons who are intimately familiar with power conversion circuitry. Lethal mains referenced voltages and high dc voltages are present within the primary section of the ATX circuitry. All testing should be done using a mains high-isolation transformer to power the demonstration unit so that appropriate test equipment probing will not affect or potentially damage the test equipment or the ATX circuitry. The evaluation engineer should also avoid connecting the ground terminal of oscilloscope probes or other test probes to floating or switching nodes (e.g. the source of the active clamp MOSFET). It is not recommended to touch heat sinks, on which primary active components are mounted, to avoid the possibility of receiving RF burns or shocks. High impedance, low capacitance test probes should be used where appropriate for minimal interaction with the circuits under investigation. Particular care should be taken when probing the high impedance input pins of the NCP1653 power factor controller and the NCP1562 active clamp controller. As with all sensitive switchmode circuitry, the power supply under test should be switched off from the ac mains whenever the test probes are connected and/or disconnected.The 3.3 V output does not have a minimum load requirement and a preload resistor is included in the -12 V output.The NCP1027 standby flyback converter will be operational as long as there is ac mains voltage applied to the system. This auxiliary converter can be evaluated by merely applying the mains voltage to the board. The supervisory IC enable input and monitoring circuitry will have to be disabled. The supervisory circuitry will normally cause a shutdown of the PFC (and the main converter) if the 3.3 V, the 5 V and the 12 V outputs are not sensed at their nominal voltage.The evaluating engineer should also be aware of the idiosyncrasies of constant current type electronic loads when powering up the ATX demonstration unit. If the loads are adjusted to be close to the ATX’s maximum rated output power, the unit could shut down at turn on due to the instantaneous overloading effect of the constant current loads. As a consequence, electronic loads should be set to constant resistance mode or rheostats should be used for loads. The other alternative is to start the supply at light to medium load and then increase the constant current electronic loads to the desired level.The board is designed to fit in a traditional ATX enclosure as shown in Figure23.Figure 23: ATX solution boards in ATX enclosure6. SchematicsThe power supply is implemented using a single sided PCB board. Added flexibility is provided by using daughter cards for the PFC (NCP1653), active clamp (NCP1562) controllers. A PCB board is also used for the 3.3 V post regulator (NCP4330) and supervisory controllers. This allows the use of newer generation controllers without the need of a complete re-layout of the main board. An additional daughter card is used for EMC components. The individual PCB board schematics are shown in Figure 24 through Figure 27.The schematic of the main PCB board is divided in three sections: PFC & standby section, active clamp section, and the post regulator section as shown in Figure 28 through Figure 30, respectively.Figure 24: PFC controller PCB board schematicFigure 25: EMC component boardFigure 27: Supervisory and 3.3 V post regulator controller PCB board schematicFigure 28: Main PCB board schematic PFC and standby sectionFigure 29: Main PCB board schematic active clamp stage sectionFigure 30: Main PCB board schematic 3.3 V post regulator section7. Parts ListThe bill of materials (BOM) for the design is provided in this section. To reflect theschematics shown in the previous section, the BOM have also been broken into differentsections and provided in separate tables – Table 5 through Table 9.It should be noted that a number of components used during the development cycle werebased on availability. As a result, further cost reductions and better inventorymanagement can be achieved by component standardization. IE, the unique part numberscan be SIGNIFICANTLY reduced by standardization and re-use of component valuesand case sizes. This will result in a lower cost BOM and better inventory management.Description Part Numbers Qty 0.1µF, ±10%, 500V, X7R, Case Size 1812 VJ1812Y104KXEAT 3 0.1µF, ±10%, 50V, X7R, Case Size1206 B37872K5104K060 18 0.1µF, ±20%,300VAC, Interference Suppression CapX2 PHE840EB6100MB05R17 2 0.22uF, ±20% ,300VAC, Interference Suppression CapX2 PHE840EX6220MB06R17 1 270µF, ±20%, 400V, -40°C to +85°C, B43501 series , Snap-In, Pitch 10mm B43501A9277M000 1 100pF, ±10%, 1kVDC,High voltage ceramic disc Capacitor, -25°C to +85°C DEBB33A101KC1B 2 100pF, ±5%, 50V, COG, Case Size1206 B37871K5101J060 1 1nF, ±20% , 100V , Stacked-film capacitor, MMK series , 5mm Pitch MMK5 102M100J01L4 BULK 2 1nF, ±10%, 1kVDC,High voltage ceramic disc Capacitor,-25°C to +85°C DEBB33A102KA2B 2 1nF, ±20%,, 440VAC,Interference Suppression CapY1 PME294RB4100MR30 2 1nF,±20%, ,440/250VAC,Interference Suppression CapX1/Y2 2252 812 35 027 1 1nF, ±10%, 100V, COG, Case Size1206 B37871K1102J560 5 4.7nF, ±10%, 1kVDC, High voltage ceramic disc Capacitor, -25°C to +85°C DEBB33A472KA3B 1 4.7nF,±10% ,440/250VAC,Interference Suppression CapX1/Y2 2252 812 35 427 1 10nF, ±20% , 100V , Stacked-film capacitor, MMK series , 5mm Pitch MMK5 103M100J01L4 BULK 1 10nF, ±10%, 50V, X7R, Case Size1206 B37872K5103K060 1 22nF, ±20% , 100V , Stacked-film capacitor, MMK series , 5mm Pitch MMK5 223M100J01L4 BULK 1 2n2F, ±5%, 50V, COG, Case Size1206 B37871K5222J060 1 470pF, ±5%, 50V, COG, Case Size1206 B37871K5471J060 1 10µF, ±20%, 16V,-40°C to +85°C, Type VR, Radial, Pitch 2mm, Pb Free UVR1C100MDD 4 220µF, ±20%, 25V,-40°C to +85°C, Type VR, Radial, Pitch 3.5mm, Pb Free UVR1E221MPD 1 3300µF, ±20%, 10V,-40°C to +85°C, Type VR, Radial, Pitch 5mm, Pb Free UVR1A332MHD 1 47µF, ±20%, 25V,-40°C to +85°C, Type VR, Radial, Pitch 2mm, Pb Free UVR1E470MDD 1 2200µF, ±20%, 10V,-40°C to +85°C, Type PM, Radial, Pitch 5mm, Pb Free UPM1A222MHD 2 220µF, ±20%, 25V,-40°C to +85°C, Type PW, Radial, Pitch 3.5mm, Pb Free UPW1E221MPD 2 470E, ±1%, 0.25W, Case Size 1206 MCR18 EZH F-4700 1 0.2E, ±1%,1W, Case Size 2010 CRL1206-FW-0R20E_ 3 0E022, ±5%, 3W,Wire Wound Resister BSI680E022±5%±100ppm/°C 1 100E, ±1%, 0.25W, Case Size 1206 MCR18 EZH F-1000 1 100E, ±1%, 0.25W, MFR EROS2CHF1000 2 10E0, ±1%, 0.25W, Case Size 1206 MCR18 EZH F-10R0 2 10E, ±1%, 0.5W, Case Size 2010 MCR50-JZH-J 10R0 5。

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