As electronic systems become smaller and more complex, requiring multiple power rails, systems designers are increasingly challenged to optimize power solutions for higher densities, higher reliability and lower cost. Instead of relying on off-the-shelf modules, systems designers often need to design their own power solutions
The power supply is no longer an afterthought in systems design. In fact, it is usually the weakest link; power components bear the brunt of stresses imposed by voltage, current and temperature, all of which can shorten component lifetimes and affect reliability.
Optimizing power solutions is more urgent today, but it’s no walk in the park. Switching-converter design is an arcane skill to most non-power electronics engineers. The best way to understand it is in terms of energy flow — how input energy can be stored temporarily, and transferred to the output at the right voltage.
Switch mode circuits are networks of energy storage elements (inductors and transformers for storage in magnetic fields, and capacitors that store energy in electric fields), transistors for power switching and diodes for rectification. The particular arrangement of these components – the “topology” – determines when energy is transferred from the input to the load. Most engineers who are not power specialists are familiar with the “buck” topology in which energy transfer occurs during the conduction state of the switching transistor, and the ”flyback” topology in which the energy is delivered to the output during the “off-state” of the switch.
Broadly, topologies may be classified as “non-insolated,” which are simpler, and “isolated,” which use a transformer. Beyond that there are dozens of variations. A familiarity with the basic types (here’s a handy pocket reference) allows a systems designer to better select the topology that meets all the requirement of the system including cost, size, time to market and production volumes.
The power solution is a critical factor today in systems design. Engineers ignore it at their peril.