TIDUDO6B May 2019 – October 2020
For high efficiency, the inductor must have a low DC resistance to minimize conduction losses. Especially at high-switching frequencies, the core material has a greater impact on efficiency. When using small chip inductors, efficiency is reduced mainly due to higher inductor core losses. This must be considered when selecting the appropriate inductor. The inductor value determines the inductor ripple current. The larger the inductor value, the smaller the inductor ripple current and the lower the conduction loss of the converter. Conversely, larger inductor values cause a slower load-transient response. The peak current for the inductor in steady-state operation can be calculated to avoid saturation of the inductor with the chosen inductance value. The equation which defines the switch current in boost mode is reported, because it provides the highest value of current and represents the critical current value for selecting the right inductor.
where
Figure 2-14 shows the schematic for the buck-boost converter, TPS63036.