Contents
What is an interleaved buck converter?
The interleaved synchronous buck converter is a popu- lar solution to supply high-current microprocessors because of the lower input and output current ripple and higher operating frequency of input and output capacitors in comparison with the one-channel solution.
Why do we use interleaved converters?
The converters are controlled by interleaved switching signals, which have same switching frequency but shifted in phase. Using interleaved converter we can get improved efficiency, reduced ripple voltage, reduced inductor current ripple, fast switching speed.
How to choose the correct inductor for a buck converter?
For a buck converter, choosing the correct value of inductance is important to obtain acceptable inductor and output capacitor sizes and sufficiently low output voltage ripple. As you can see from Fig. 1, the inductor current is made up of ac and dc components.
Can a buck converter be operated in discontinuous mode?
You can operate buck converter inductors in continuous or discontinuous mode. This means that the inductor current can flow continuously or can fall to zero during the switching cycle (discontinuous). However, operating in discontinuous mode is not recommended as it makes for a more complex converter design.
How to select the correct inductors for switching regulators?
It is normally in the order of 10-500mVpk-pk. Selecting the correct ripple current also affects the size of the inductor and the output capacitor. This capacitor must have a sufficiently high ripple current rating, or it overheats and dries out.
What should be the peak current of an inductor?
To allow some margin, you should select a value of 10µH. This gives a nominal peak-to-peak ripple current of 450mA. In the finished design, this can be seen as an output ripple voltage of 0.45 × output capacitor ESR. Inductors are normally specified with two current ratings: continuous (Irms) and peak (Isat).