How does S6BP401A suppress the input ripple RMS voltage?
Generally, additional input ceramic capacitors are often used to reduce ripple input RMS voltage. However, doing so might significantly increase bill of materials (BOM), which is undesirable.
To solve this issue, out-of-phase operation is used on neighboring channels, DD1/DD2 and DD3/DD4 of S6BP401A, as shown in Figure 1. This feature reduces the ON time overlap of neighboring channels and thus suppresses the input RMS ripple voltage and eliminates additional cost of input capacitors.
Figure 1. S6BP401A neighboring channels out-of-phase operation