As analog goes digital must digital go soft?

April 07, 2016 // By Ken Coffman
Ken Coffman
Ken Coffman, field applications engineer with Intersil, discusses the long-term evolution of electronics.

As I was studying the feedback coefficients for a buck converter digital control loop, a thought occurred to me I’d like to bounce it off you. All the converters of yore, even if they had some digital content like enable and power good signals, had analog control loops. Now, more and more, the control loops are digital.

There isn’t a one-to-one correlation between the filters, feedback compensation and PWM generation circuitry, and in some ways, the digital versions are better because functions that are impractical or impossible in analog form can be implemented in digital hardware, though it’s hard to imagine all the pieces that make a digital controller, like the microcontroller (for the serial port), the DSP, the state machine and the blocks of memory to support all of the above could ever be cost effective, but if you want to pretend your controller is part of the digital system (from the CPU point of view), this is what is needed.

It strikes me there is natural evolution happening before our very eyes. What was analog, is becoming digital. For the next step, there are already signs that the digital is becoming software. There’s the well-trodden path: analog becomes digital, digital becomes software.

Pick anything around you. Your watch was analog, then it became digital and soon it will be software. Has this already happened? How many people do you know who don’t wear a watch? Why would they when they can get accurate time from their phone. Phone? That's a portal to the cloud: which is made of software.

We see this all around us. Medicine used to be analog, then it became digital, now it’s becoming software.

Look at cars. They used to be analog, then their digital content took over. Now we have Lyft and Uber and the car experience has become more virtual. Imagine what a Google or Apple car will be like. The experience