Circuit secures bootstrap operation under light load

摘要

A previous Design Idea highlights a potential issue of a bootstrap IC under light-load or precharged-load operation (Reference 1). The circuit in Figure 1, with the additional circuit in the green box, fixes the problem of a voltage dip in the bus-voltage signal. The waveforms in Figure 2 demonstrate how this problem takes place in buck converter IC_IB when its output voltage, V_BUS, dips below the regulation point at a fixed rate under no load. By