RF/microwave design engineers faced with developing effective power circuits for a system require more complete data sheets, appropriate computer-aided simulation models, and suitable test equipment.
Power-supply designs are often overlooked as part of a high-frequency electronic system. A wide range of approaches are used—from the simplest linear regulators to switching converters and complete distributed power systems—and many of these power designs simply don’t work as well as they should. They often fail to meet key performance requirements, such as stability, regulation, ripple, and headroom. There are a variety of technical reasons why these power supply designs perform poorly, and it may help to examine these issues individually.
In many designs, the same power supply (consisting of a converter and many regulators) is used to feed various loads, which are often digital or RF in nature (Fig. 1). But the increasing speeds of devices in these circuits can mean that the transient edges of load currents are becoming more of a problem, with fast rise and fall times.