《E类功率放大器设计.doc》由会员分享，可在线阅读，更多相关《E类功率放大器设计.doc（8页珍藏版）》请在金锄头文库上搜索。
1、E类功率放大器设计 Alan Melia G3NYK, Mike Probert GW4HXO, and Finbar OConnor EI0CF艾伦苦G3NYK，迈克普罗伯特GW4HXO和Finbar奥康纳EI0CF There have been many different configurations that have attempted to squeeze the best efficiency out of an RF Power Amplifier.已经有许多试图挤进了一个最佳的效率射频功率放大器进行不同的配置。 Class E is a form of switching
2、amplifier which was patened by Nathan Sokal WA1HQC in around 1976. E类是开关放大器的形式，patened由Nathan索卡尔WA1HQC周围一千九百七十六英寸 I first saw it described in Design Electronics in 1977.我第一次看到它在设计电子所述于1977年。 Being an amateur, Nat is an extremely practical man and the article gave a test circuit that could easily be
3、assembled from laboratory components, and then measured whilst the components were altered.作为一个业余爱好者，NAT是一个非常实际的人的文章介绍了测试电路，可以很容易地从实验室组装部件，然后测量虽然成分改变。 I had little interest at that time but the article was filed away until I had attempted to modify an audio amp for 73kHz with very little success.我当时
4、的兴趣不大，但被束之高阁的文章，直到我曾试图修改一个非常小的成功为73kHz音频放大器。 I dug out the old article and read it several times.我挖了旧的文章，读了好几遍。 It did not give any guidance about where to start from in a new design, though it gave a number of optimised equations for calculating the critical component values.它没有提供任何有关从哪里开始从一个新的设计，虽
5、然它给了关键元器件的计算值的优化方程的数目指导。 I started by putting the equations into a spreadsheet and tried some numbers to see what changed, with power, supply voltage and load.我开始通过把电子表格的公式，并试图用一些数字来看看有什么改变了电源，供电电压和负载。 As a result I think I gained a feeling for the circuit and developed a recipe for the process of p
6、roceeding through a design因此我认为我获得了该电路的感觉，制定了通过诉讼程序设计一个配方 The following notes are a result of experimental work, and in no way add to the theory which has been adequately covered by Nat and Fred Raab in many papers.下面的说明是一个试点工作的结果，绝不添加到已获得足够的NAT和弗雷德拉布多篇论文涵盖理论。 My objective was to try and formulate a
7、n easy route to a medium power 136kHz power amplifier, which would be relatively benign.我的目的是试图制定一个简单的路由到中等功率136kHz功率放大器，这将是相对温和。 By benign I mean a circuit that did not have an insatiable appetite for FETs.我指的是由良性电路，没有一个场效应管贪得无厌的胃口。 The RSGB LF reflector has carried stories from time to time of exp
8、loding FETs and of complex protection circuits to circumvent this problem.低频反射的RSGB已进行的故事不时爆炸场效应管的时间和复杂的保护电路来绕过这个问题。 My naive thinking was that a switch which is either on or off should form the basis for the circuit, using a single ended design to avoid the cross-coupled oscillator effect.我天真的想法是，这
9、是一个开关打开或关闭应成为电路的基础上，采用单端设计，以避免“交叉耦合振荡器效应”。 It seemed that some LFers had already been playing on the verge of Class-E but there was no information with the circuits and it seemed they did not really know how it worked or how to set it up.这似乎有些LFers已经对E类边缘打，但没有与电路资料，而且似乎他们真的不知道它是如何工作和如何设置它。 Unlike ma
10、ny PAs that we are familiar with, you cannot just increase or decrease the power from a Class E PA by varying the loading on it.不像我们所熟悉的许多功率放大器，你不能只是增加或减少其上的负荷变化从一个E类功率放大器的力量。 The first important thing to appreciate is that a Class E PA is designed for a particular power output, and it will only be
11、efficient at this design power level.首先重要的是要明白的是，一个E类功率放大器是为特定的输出功率设计的，它只会在这个设计功率效率。 Click here to download Excel worksheet http:/www.alan.melia.btinternet.co.uk/download/classe.zip点击这里下载Excel工作表http:/www.alan.melia.btinternet.co.uk/download/classe.zip Design proceedure设计过程 1. 1。 Select a Power Supp
12、ly voltage (Vdd).选择一个电源电压（Vdd）。 2. 2。 This determines the Vdd(max) of the FET at approximately 3.5 times Vdd这就决定的VDD（最大值）的约3.5倍，在Vdd的场效应管 3. 3。 Select the target power level选择目标功率水平 - This determines the optimum value of C1 and the optimum load impedance -这就决定了C1的最佳值，最佳负载阻抗 4. 4。 Determine the the v
13、alue of C2 and L2 from the Excel worksheet确定从Excel工作表中的C2和L2的价值 Nats original paper didnt give guidance but his later QEX paper suggests that the value of the choke L1 is not critical, but it should have an inductance with a reactance at least 30 times the optimum load impedance. Nat的原始文件没有给予指导，但他后来
14、QEX文件建议，该扼流圈L1的并不重要，但它应该有一个电抗至少30倍的最佳负载阻抗电感。 this means at 136kHz a minimum of around 500uH.这意味着在136kHz左右的500uH最低。 I have been using a choke of 5mH as I want to operate at 73kHz as well.我一直在使用的5mH呛，因为我想在73kHz运作良好。 Also I suspect that the larger choke will give a softer keying risetime.此外，我怀疑大呛会给一个软键
15、控上升时间。 Now for some practical details.现在对一些具体细节。 The point of Class E is that there is no power wasted other than the Idss*rds(on).在E类的一点是，有浪费比其他的RDS的IDSS *（上）没有权力。 This is achieve by the series circuit C2L2.这是实现由串联电路C2L2。 Because C2 will have to be made up from standard values of pulse rated HV cap
16、acitors it is necessary to have some adjustment on L2 for initial set up.由于C2的将须从高压脉冲电容器额定标准值的注册必须有一些初始设置二级调整。 You will see in the worksheet a column which calculates the resonant frequency of L2C2, and may be somewhat surprised to see that it differs from the driving frequency.你会看到一列在工作表中，计算了L2C2谐振频率，并可能有点惊讶地看到，它从驱动频率不同。 This is because this circuit is NOT a tuned circuit to extract the power at 136kHz.这是因为这个电路是不是一个调谐电路在136kHz提取
