How Does A Microchip Work, Anyway?

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It is a big ol’ nano world out there, isn’t it? – We humans are pretty much awestruck by things that are extreme in size one way or the other. We marvel at our engineering prowess when we look up at some of the tallest skyscrapers in the world, and we also marvel at our ability to make computers and smartphones work with electronic components that are barely visible to the human eye – and require a microscope to get details.

Often, we are amazed at the final result of our engineering and we don’t really think much about how it works or what it took to get that major achievement. Perhaps we get even more impressed if we learn how we got the structure and what it took to get there.

We can use a microchip, or just a chip for short, as an example of the engineering genius that we have reached – the idea of millions of calculations per second being conducted on a chip no bigger than a thumbnail. Meanwhile, barely 50 years ago, you needed an entire room to hold a computer that could conduct only hundreds of calculations per second. But while you see a silicon wafer holding a number of these chips and you can make out some of the circuits, do you really have an understanding of how these chips work?

Let’s take a quick tour through the nano world of a microchip.

Its Basic Structure

A microchip is, in its most basic sense, the brain and nerve center of an electronic device. Your own brain, for example, will get an instruction and process it, and then tells your body how to execute that instruction (moving your hands in a certain way or lifting your foot).  And like your own human nervous system, a microchip has a very diverse but organized “tangle” of electric circuits, all of which serve their own purpose in terms of processing the myriad calculations that are asked and sending the result to the appropriate part of the electronic device. For example, there is a transistor or circuit that tells the computer to turn on, or to activate the camera on your smartphone, or to open iTunes or Google Play. Virtually every function of your computer has a corresponding circuit, and all those circuits are on a chip.

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3 Basic Functions

No matter how many circuits you have and how much memory is stored on the chip, a chip basically has three functions, and each of the circuits perform at least one of these functions:

  1. Perform math operations. Yes, this is addition, subtraction, multiplication and division. Of course some functions are complex versions of these, but still.  Some functions can only be performed once a certain math equation is worked out, and the answer determines what is executed.
  2. Move data from one place to another. Sometimes a piece of data is used and processed more quickly in one part of the device than another. Like on your smartphone, data pertaining to your camera might be better in an area closer to the camera, while data to execute the phone functions would be more efficiently processed nearer that part of the memory.
  3. Makes decisions and then moves to a new set of instructions based on the decision made. Remember the flow charts we used to draw up? Those flow charts – with lines and arrows between ovals, rectangles, squares and the diamond “decision” shape – essentially covered this function. Like, “Is your leftover meal warm enough?” in the diamond shape. “Yes” would point to a rectangle that says “Enjoy your meal.” A “no” line would lead back to the rectangle above the diamond that says “Place your meal in the microwave for a set amount of time and push Start.”

How Does My Computer Seem So Fast?

Not all processes happen in the blink of an eye. Processors have “clock cycles” that determine the speed at which the processor can process a basic instruction. However, often these computers are asked to perform executions that may take longer – such as showing advanced graphics or streaming video. These types of operations are very complex, so often chips are made with circuits that overlap each other – in other words, there could be multiple circuits made to execute that complex instruction more quickly through a process called pipelining. This process stages a complex operation so it will be executed much faster than a single circuit would. For example, if streaming a piece of video takes six “clock cycles” to complete, the silicon wafer chip will have six circuits dedicated to streaming video, and each circuit will be at a different stage of the process during each “clock cycle” so that it will seem that that particular task is being executed at every single cycle. This explains smoother streaming of video and video that buffers or jumps around or freezes on occasion – it often depends on the number of circuits that are dedicated to that video streaming power and whether there are enough circuits to make the execution seamless.

There are some articles that go into great and technical details about how chips work, but this should at least give you a very basic sense of what happens “under the hood” of a computer device at the microchip level.

About the Author

David Woodburn has been working in technology for the last few years and recently started working with microchips.

Photo credit: Peter Shanks / Meneer Dijk

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