当电子设计让我写关于我的Idea for Design, first seen in this year’s August 13 issue, it seemed a simple enough task. We’re all familiar with design. Most of us do it in some form or another almost every day. But, ideas? We all have them, but where do they come from? And what is the essence of a good idea? Simplicity? Elegance? Performance, novelty, creativity?
托马斯·爱迪生（Thomas Edison）曾经说过天才是1％的灵感和99％的汗水。对我来说，灵感是关键。拥有一个好主意并将其变成出色的设计需要灵感的种子。作为专门从事模拟设计的顾问工程师，我设计的大多数电路都遵循客户的规格。创建对客户需求执行的产品是一个挑战，如果我要以可靠，高效且以合适的价格执行的电路满足这些要求，则需要灵感。这通常就是好主意的来源。
但这并不总是这样。有时，一个想法仅仅是由于希望做一些不同，更好或更便宜的事情而实现的。它可能突然发生在我身上。我倾向于皱眉，古怪，看起来很遥远。朱莉（Julie），我最近和最亲爱的人总是可以说。“您得到了其中一个想法，不是吗？”她说。我通常会说出令人讨厌的点头，然后跑去我的书房。我保留了很多纸，并方便地抚摸铅笔。您永远无法分辨出一个想法何时会发生。
So it was with the rectifier idea. I’d been going through my burgeoning collection of electronics literature, reflecting on the merits of different active rectifier circuits. Some of them were half-wave, others full-wave. Most of them used diodes inside an op amp’s feedback loop. Others used clever arrangements of op amps and analog switches. All very neat, all very effective. But something nagged at me. If I were to feed an alternating signal swinging symmetrically about ground into a single-rail op amp, what would the output look like? Wouldn’t the negative peaks be clamped to ground? And wouldn’t that, effectively, be half-wave rectification?
我跑去学习，开始乱涂乱画。朱莉，祝福她，给我带来茶和一片比萨饼。第一部分很容易。op-amp IC1A被配置为在单个正轨上运行的统一生成的追随者，确实会遵循输入波形的正段段，并将在负数部分的下面升级。我添加了电阻R1，以保护运算放大器的非反转输入免受大型，负输入波动的过多电流流量。
到目前为止，我对不需要任何二极管或模拟开关的半波整流器有一个有希望的想法。极好的。但是我想要全波纠正。除了添加第二个OP放大器IC1B，别无其他。By combining the second op amp in a unity-gain inverting function with the output of the non-inverting follower, the overall function would simply invert the negative-going input peaks when IC1a’s output was at ground to produce a positive-going version and would effectively allow IC1a’s output to follow through during the positive-going peaks, producing full-wave rectification.
Genius? Absolutely not. All I did was to take some wellestablished techniques and combine them in a way that suited my idea. Certainly, the resulting circuit is fairly unique to me, but the foundations it is based on are not. “If I have seen further it is by standing on the shoulders of giants,” said Isaac Newton. The giants of analog design are the likes of George Philbrick, Bob Widlar, and Barrie Gilbert, and latter-day luminaries like Bob Pease and Jim Williams continue to guide my way.
因此，一切都适合大信号，但是较小的信号呢？我想添加增益，因此可以将几百毫米的信号提升到几伏。我知道，将R4和R5添加到IC1A将需要用于输入信号的正极部分所需的AMS，但是R2与R3的比率决定了第二阶段的倒数增益，因此必须更改为正负峰将平等放大。是时候进行一些数学的时间 - 没有花哨的时间，只是一个代数。通过将正面和负偏移过程中的总体增益等同于表达式，我得出了一个简单的方程式，该方程可用于确定电阻器值。
Is there a route map for good design? Possibly. But there are different ways to turn that spark of an idea into a living, breathing circuit. There are no hard and fast rules. Find the way that works best for you. I like to scribble, tweak, do the math if necessary, then maybe run a few PSpice simulations. Only when things are looking good at this stage do I move to the breadboard. I rarely rely on simulation results to prove a circuit. For me, the breadboard is the final arbiter. For really simple circuits, I sometimes use the matrix-type breadboards where you simply plug in the components, but they have their limitations. I much prefer to solder components onto a piece of copper-clad board. As well as providing a secure anchor for the parts, it functions as a low-impedance ground plane.
What would be my advice for good design? Try the three R’s—read, research, revise. Plenty of good literature is available on electronic design, not just in textbooks, but also in manufacturers’ application notes and magazines likeElectronic Design。彻底的研究至关重要，尤其是在选择合适的组件时。我仅在仔细评估了诸如相反行为和过载恢复时间之后，才在整流器电路中使用OPA2374双OP放大器。最后，修改。没有完美的设计。电路始终可以改进。
And remember to think “out of the box.” It’s an overused phrase, but important nonetheless. That’s effectively what I did with the rectifier circuit by using a single-rail op amp in an unusual way. Most designs would strive to avoid saturating an op amp’s output, whereas the rectifier circuit actually exploits that behaviour. I like to design circuits just for the hell of it. It’s fun, and I continue to learn from the process.
So, is this idea thing an addiction? Probably. As long as I keep getting a buzz from analog design and that sweet rush of anticipation whenever I warm up my soldering iron and turn on my oscilloscope, I’ll carry on turning ideas into designs and, with a little inspiration, I hope to continue sharing them with you.
