我现在想知道的是坛子里谁家有真的在卖{:1_292:}
yp100yp 发表于 2012-11-2 13:33 static/image/common/back.gif
牛啊！没看懂为啥用两个功率管（ＩＲＦＰ250），看样子少一个也没问题啊？
有小柯达的电路吗？ ...
一个是开关管，另一个是用来钳位电压尖峰的，伟创力的专利。那位DX说的。
假冒用爱瓦特的方案！！！
ipad原装2安充电器大多用爱瓦特方案，爱瓦特ic都不便宜，
这里作者应该有错误之处，出于严谨，先不说了。
MAGLITE 发表于 2012-10-12 14:23
蘋果公司巨大的利潤空間
我驚奇地發現，蘋果的利潤率必須在這些充電器的巨大。這些充電器的售價為30元左右...
做记号，有几个正要修
边际力度 发表于 2012-11-2 22:08 static/image/common/back.gif
假冒用爱瓦特的方案！！！
ipad原装2安充电器大多用爱瓦特方案，爱瓦特ic都不便宜，
这里作者应该有错误之 ...
是指那位DX，还是我翻译的不当？
真和小柯达一样的
苹果的利润我对于苹果在该充电器上的巨大利润感到非常惊讶。该充电器售价大概是30美元，其利润也几乎是这个价钱了。三星有款类似的小方块充电器，售价大概是6-10美元，同样我也拆开来看了（以后会写个详细的文章介绍）。苹果充电器的质量很好，估计会比普通充电器在成本上多1美元左右，但他却要卖20多美元！ 苹果2008年充电安全召回在2008年，苹果召回了iphone充电器，因为充电器的AC插脚存在着可能掉出或折断，并留在插座上。缺陷产品给人的印象是，插脚上只搞了些胶水来固定它。苹果召回了充电器，并从新设计了结构，新产品上会有个绿色的圆点，和之前的缺陷产品区别开来。（原来绿点是这样来的。-rollei120注） http://img04.taobaocdn.com/imgextra/i4/61254005/T2y1SyXXpbXXXXXXXX_%21%2161254005.png
我决定要对比一下旧产品，看看苹果在新设计中到底改进了什么。我拆卸了苹果充电器，三星充电器和一个劣质的充电器，看看AC脚有什么不同。那个劣质的充电器，用钳子用一点力就能把AC脚拔出来，里面没有任何的卡扣，只靠一点摩擦力支撑。三星充电器的插脚，需要借助钳子用较大的扭力，因为插脚上设计有一些金属卡扣去固定在塑壳上，不过最终还是能把插脚拔出来。 当我拆苹果的插脚时，插脚根本就动不了，即使我用尽力气！我只好用上打磨机，想办法切开塑壳，看看到底是什么卡住插脚的。原来是一个插脚上设计有一个很大的金属平台，嵌入到塑壳里面。这样插脚是不可能再出现松动或是掉出来的情况的。下面的图片从左到右，是苹果插头（右边脚的插头上的塑胶壳已经被磨去一半。），劣质充电器插头，只靠一点摩擦力固定，和三星插头，靠一个小的金属卡扣固定。 http://img02.taobaocdn.com/imgextra/i2/61254005/T2B0WZXf8XXXXXXXXX_%21%2161254005.jpg
苹果在召回产品后，所做的努力令我印象深刻。他们不是仅仅改进一点，让插脚稳固。而是改进到，无论任何人，任何情况下，都绝对不可能再出现之前插头掉出的问题。 苹果iphone充电器的特别之处很显然，苹果充电器的质量是一流的。苹果在EMI（电磁干扰）方面是下足了功夫的，也是为了在充电时不干扰电容屏的正常工作（山寨充电器会让屏幕漂移，相信一些人已经体验到这一点了。-rollei120注）。当我拆充电器的之前，我以为充电器都是些标准的设计，但当我比较了三星和其他几款高品质的充电器之后，发现苹果的设计在几个方面超前对手许多。 在AC的输入线上，有个小的环形磁芯粘在塑壳里（见下面的图片）。桥堆之后有2个大的滤波电容和滤波电感。桥堆上还加了2组R-C缓冲滤波电路，这样的设计，我只是在给音响供电的电源里看到，为了滤除60Hz的谐波，可能这样做能让用户在听iTunes时，感觉更好。我拆其他充电器时，都没有看到有用滤波磁芯的，而且通常也只用一个滤波电容。在初级电路板上，有一个接地的金属屏蔽板，覆盖在那些高频元件之上（见图片），这也是我不曾在其他充电器上看到的。变压器里加了屏蔽绕组来吸收EMI干扰。输出端，用了3颗电容，包括2个相对较贵的钽电容，和一个电感来滤波，大多数的充电器里只会用1个电容而已，有些充电器连Y电容也省略掉了（有些IC的方案本身是不用Y电容的。-rollei120注）。另外，那个谐振钳位电路更是革命性的。 安全保护方面，苹果的在设计里更是提供了几层防护，我在上面已经介绍过了：超牢固的AC插脚设计，复杂的过温/过压保护关断电路，初级和次级的安全隔离距离已经远超一般标准。 http://img03.taobaocdn.com/imgextra/i3/61254005/T2suGvXjFbXXXXXXXX_%21%2161254005.jpg
结论苹果运用了许多技术和努力来把充电器小型化，相比其他品牌充电器却有更高的品质和安全性，当然这也带来了更高的价钱。 如果你对电源感兴趣，请看我的另外一篇文章：小，便宜，但危险的山寨iphone充电器（tiny,cheap, dangerous: Inside a (fake) iPhonecharger），那篇文章里，我拆解了一个2.79美金（差不多18元人民币）的山寨iphone充电器，里面完全不符合安全规则，奉劝大家不要购买。另外，也可以看看这篇文章：苹果并未对电源技术变革，但新的三极管做到了（Appledidn't revolutionize power supplies; new transistorsdid），那里回顾了开关电源的历史。这里有拆解苹果电源的视频，是scourtheearth和 Ladyada.制作的。最后，如果你对电源有兴趣，并且身边有许多闲置不要的电源，那就寄给我，或许我会在拆解后，写个相关的文章。 注释和参考资料（这些我就不翻译了。-rollei120注） You might wonder why theDC voltage inside the power supply is so much higher than the linevoltage. The DC voltage is approximately sqrt(2) times the ACvoltage, since the diode charges the capacitor to the peak of theAC signal. Thus, the input of 100 to 240 volts AC is converted to aDC voltage of 145 to 345 volts internally. This isn't enough to beofficially highvoltage but I'll call it high voltage for convenience.According to standards, anything under 50 volts AC or 120 V dc isconsidered extra-lowvoltage and is considered safe under normal conditions. ButI'll refer to the 5V output as low voltage forconvenience.
The Apple power supply uses a flyback design, where thetransformer operates "backwards" from how you might expect. When avoltage pulse is sent into the transformer, the output diode blocksthe output so there is no output - instead a magnetic field buildsup. When the voltage input stops, the magnetic field collapsescausing voltage output from the transformer. Flyback power suppliesare very common for low-wattage power supplies.
The primary board measures about 22.5mm by 20.0mm,while the secondary board is about 22.2mm by 20.2mm. For more information on X and Y capacitors, seeKemet's presentation and Designing low leakage current power supplies.
For clarity, some insulation was removed before takingthe pictures in this article. The Y capacitor was covered withblack heat shrink tubing, there was tape around the side of thecircuit, the fusible resistor was covered with black heat shrinktubing, and there was a black insulating cover over the USBconnector.
Snubber circuits can be used to reduce 60 Hz humgenerated by the diode bridge in audio power supplies. A detailedreference on R-C snubbers for audio power supply diodes is Calculating OptimumSnubbers, and a sample design is An Audio AmplifierPower Supply Design.
The power supply is controlled by the L6565quasi-resonant SMPS (switched-mode power supply) controller chip(datasheet).(To be sure, the chip could be something else, but the circuitexactly matches the L6565 and no other chip I examined.)
To improve efficiency andreduce interference, the chip uses a technique known asquasi-resonance, which was first developed in the 1980s. The outputcircuit is designed so when the power is switched off, thetransformer voltage will oscillate. When the voltage hits zero, thetransistor switches back on. This is known as Zero VoltageSwitching because the transistor is switched when there isessentially no voltage across it, minimizing wasted power andinterference during switching. The circuit remains on for avariable time (depending on the power required), and then switchesback off, repeating the process. (See Exploring quasi-resonant converters for power supplies for moreinformation.)
One interesting consequenceof quasi-resonance is the switching frequency varies depending onthe load (with 70kHz as a typical value). Early power supplies suchas the Apple II power supply used simple variable-frequency circuitsto regulate the power. But in the 1980s, these circuits werereplaced by controller ICs that switched at a fixed frequency, butvaried the width of the pulses (known as PWM). Now, advancedcontroller ICs have gone back to variable frequency controls. Butin addition, super-cheap knockoff power supplies use variablefrequency circuits almost identical to the Apple II. So bothhigh-end and low-end chargers are now back to variablefrequency.
It took me a long time torealize that the "FLEX01" marking on the controller IC indicatesFlextronics, and the X on the chip was from the Flextronics logo:. I assume the chip has these markings because it is beingmanufactured for Flextronics. The "EB936" marking on the chip couldbe Flextronics' own part number, or a date code.
I thought Flextronics was just an electronics assemblerand I was surprised to learn that Flextronics does a lot ofinnovative development and has literally thousands of patents. Ithink Flextronics should get more credit for their designs. (Notethat Flextronics is a different company than Foxconn, whichmanufactures iPads and iPhones and has the controversy over workingconditions).
The picture above is fromFlextronics Patent 7,978,489: Integrated Power Converters describes anadapter that looks just like the iPhone charger. The patent itselfis a grab bag of 63 assorted claims (spring contacts, EMI shields,thermal potting material), most of which are not actually relevantto the iPhone charger.
Flextronics Patent 7,924,578: Two Terminals Quasi Resonant Tank Circuitdescribes the resonance circuit used in the iPhone charger, whichis shown in the following diagram. Transistor Q2 drives thetransformer. Transistor Q1 is the clamp transistor, which directsthe voltage spike from the transformer into resonance capacitorC13. The innovative part of this circuit is that Q1 doesn't needspecial drive circuitry like other active clamp circuits; it isself-powered via the capacitors and diodes. Most charger powersupplies, by contrast, use a simple resistor-capacitor-diode clampwhich dissipates the energy in the resistor.
Later Flextronics patent**tend the resonance circuit with even more diodes and capacitors:see patents 7,830,676, 7,760,519, and 8,000,112
Apple indicates the charger type through a proprietarytechnique of resistances on the USB D+ and D- pins. For details onUSB charging protocols, see my earlier references.
One puzzling feature of the Apple charger is thesecond feedback circuit monitoring the temperature and outputvoltage. This circuit on the secondary board consists of athermistor, a second 431 regulator, and a few other components tomonitor the temperature and voltage. The output is connectedthrough a second optocoupler to more circuitry on other side of thesecondary board. Two transistors are wired in a SCR-like crowbarlatch that will short out the auxiliary power and also shut downthe controller IC. This circuit seems excessively complex for thistask, especially since many controller ICs have this functionalitybuilt in. I could be misunderstanding this circuit, because itseems that Apple unnecessarily took up space and expensivecomponents (maybe 25 cents worth) implementing this feature in sucha complex way.
Note the mysterious "For use with informationtechnology equipment" on the outside of the charger. This indicatesthat the charger is covered by the safety standard UL 60950-1, which specifies the various isolation distancesrequired. For a brief overview of isolation distances, see i-SpecCircuit Separation and some of my earlier references.
Some notes on the components used: On the primaryboard, the JS4 package is two diodes in a single package. The inputdiodes labeled 1JLGE9 are 1J 600V 1A diodes. The switchingtransistors are 1HNK60 600V 1A N-channel MOSFETs. The values ofmany of the resistors and capacitors are indicated through standardSMD three-digit markings (two digits and then a power of ten,giving ohms or picofarads).
On the secondary board, the"330 j90" capacitor is a Sanyo POSCAPtantalum polymer 300mF 6.3V capacitor (j indicates 6.3V and 90 is adate code). 1R5 indicates a 1.5uH inductor. GB9 is a AS431I lowcathode current adjustable precision shunt regulator, and 431 is aregular TL431 regulator. SCD34 is a 3A 40V schottky rectifier. YCWis an unidentified NPN transistor and GYW is an unidentified PNPtransistor. The Y capacitor labeled "MC B221K X1 400V Y1 250V" is a220nF Y capacitor. The "107A" capacitor is a 100 µF 10V tantalumcapacitor (A indicates 10V). The optocouplers are PS2801-1. (Allthese component identifications should be considered tentative,along with the schematic.)
In order to get a rough idea of how much thecomponents in the charger cost, I looked up the prices of somecomponents on octopart.com. Theseprices are the best prices I could find after a brief search, inquantities of 1000, attempting to match the parts accurately. Ihave to assume Apple's prices are considerably better than theseprices.
ComponentPrice
0402SMD resistor
$0.002
0805SMD capacitor
$0.007
SMDtransistor
$0.02
fusible resistor
$0.03
1A600V (1J) diode
$0.06
thermistor
$0.07
Ycapacitor
$0.08
3.3uF 400V electrolytic capacitor
$0.10
TL431
$0.10
1.5uH inductor
$0.12
SCD34 diode
$0.13
2801optocoupler
$0.16
1HNK60 transistor
$0.22
USBjack
$0.33
100uF tantalum capacitor
$0.34
L6565 IC
$0.55
330uF tantalum polymer capacitor
(Sanyo POSCAP)
$0.98
flyback transformer
$1.36
A few notes. Flybacktransformers are generally custom and prices are all over theplace, so I don't have much confidence in that price. I think thePOSCAP price is high because I was looking for the exactmanufacturer, but tantalum capacitors are fairly expensive ingeneral. It's surprising how cheap SMD resistors and capacitorsare: a fraction of a penny.
Apple's safety recall of chargers was announcedin 2008. Blogreports showed that the prongs on the charger were attachedonly by 1/8" of metal and some glue. AppleRecalls iPhone 3G Power Adapters in Wired provides moredetails.
Low-quality chargers interfere with touchscreens, andthis is described in detail in Noise Wars: Projected capacitance strikes back. (Customers alsoreport touchscreen problems from cheap chargers on Amazon and other sites.)
There are many industry designs for USB AC/DCconverters in the 5W range. Sample designs are available fromiWatt, Fairchild,STMicroelectronics,Texas Instruments, ON Semiconductor, and Maxim.
When a diode or transistor switches, it creates avoltage spike, which can be controlled by a snubber or clampcircuit. For a lot of information on snubbers and clamps, seePassiveLossless Snubbers for High Frequency PWM Conversion andSwitchmodePower Supply Reference Manual.
感谢楼主分享 老外真牛逼 又上了一堂模电课
楼主技术流啊，英文不错
这种帖子一定要支持
非常好的文章，值得借鉴！
贵有贵的道理！{:1_300:}
有时间看看
苹果充电器厉害！
技术文章，收藏一个。
翻译很好，一看就明白，感觉翻译对电路也很了解。
没必要吹到天上去吧，我看柯达的和微软的小充也做得不差。
说来说去充电器这东西还不就那几家专门代工电源类产品的工厂做的。
这篇出来之后没多久就被批判过了
多谢分享................