Downsizing is also a critical requirement nowadays. Downsizing can be achieved by opting for the switching system. In the section on AC/DC conversion basics, we showed examples of AC adapters which illustrate differences between the switching and transformer systems.
The transformer, which is a bulky and heavy part, has undergone downsizing as a constituent part. In the secondary-side DC/DC conversion circuit, the smaller inductors and capacitors can be used by increasing the switching frequency. This may be a good strategy for achieving size reductions albeit at the expense of a diminished efficiency. In this regard, optimization between size and efficiency is necessary.
Additionally, integrating the peripheral functions into the control IC can be beneficial in reducing the number of required parts and decreasing the foot print. Latest control ICs provide five or six built-in protection functions. Implementing these functions by using discrete parts will require a considerable number of parts and footprint.
・While increasing the required number of parts, the switching system can reduce the form factor.