Power is, of course, vital to any electronic product. Yet it wasn't too long ago that power supplies were one of the last things a designer considered. I've heard tales of power supply companies being asked if they can make a special because 'it has to fit this space and we don't want to redesign'.
In those days, the product plugged into the wall and the less than efficient power supply provided whatever voltage was needed to the product and some unwanted harmonics back into the main supply.
Now that many products are battery powered, the focus has shifted to designing power systems that squeeze the last drop of 'juice' from whatever battery technology is being used and to batteries that can hold more 'juice per unit volume'. Even those products still powered from a wall socket require far more attention to power quality than ever before.
I talked earlier about growing interest in solid state batteries, but another significant strand of research is lithium-sulphur. It's an attractive technology, claiming greater energy density – at least in theory – than the ubiquitous lithium-ion. But the downside is that lithium-sulphur can't be recharged as many times – at least not yet.
It seems the stumbling block is electrode technology and the scale of the problem is demonstrated by the solutions being explored – exotic composite materials in one case.
If someone can work out how to improve this, then Li-S batteries are set to become the power source of choice for portable devices.
