Moving from small arduino applications to higher-power applications for work, I've had to switch from using simple linear regulators to switching boost/buck converters any time a different voltage to what is available is required. This has been much more of a learning curve than I anticipated; things like switching frequency, inductance and capacitance values all need to be taken into account, and there are almost always several external components (for example, the inductor) required for the converter to function.
My question is, why are these additional components almost always external? I'm not complaining, I've been learning a fair bit from the switch and it's not too bad a curve, I'm just curious as to why there seem to be no plug-and-play ICs (at least not that I've found for 24V, 3A output, correct me if I'm wrong) like there are for smaller linear regulators.
My guess would be too much heat generated?
Best Answer
It has to do with the limitations of silicon.
You can easily make lots of transistors in silicon, and connect them together.
Resistors and capacitors, particularly ones with any precision, are harder, and you can't really make them to handle any appreciable energy. It can be done, but they take up lots of space (I'm not sure how things stand now, but at one point the typical internal compensation cap for a unity-gain stable op-amp took up most of the silicon).
Inductors are right out. You need low-resistance windings, you need a magnetic core, you need size.
Which is why your switching supply has a chip that does everything that can be reasonably done in silicon, then it's surrounded by (relatively) big capacitors and a (relatively) big coil.