A Two-Phase Three-Level Buck DC–DC Converter With X-Connected Flying Capacitors for Current Balancing
A Two-Phase Three-Level Buck Converter With Cross-Connected Flying Capacitors for Inductor Current Balancing

Application

  1. Envelop Tracking (包络跟踪) and point-of-load applications, because these require small form factor fast-transient converter.
  2. To balance the inductor current in 2P, 2P3L, 4P3L struture, in which P means phase, L means inductor.

Disadvantage

  1. Hard to minimize the mismatches between the two branches.

Structure

The proposed structure is shown below, however, the only change is the way of capacitor-connection.
Structure
Waveform D1,DS1,D2,DS2D_1, D_{S1}, D_2, D_{S2} control power switches S11&S24,S12&S13,S21&S14,S22&S23S_{11}\&S_{24}, S_{12}\&S_{13}, S_{21}\&S_{14}, S_{22}\&S_{23}. So the voltage of VX1V_{X1} veries VinVCF1VinVinVCF2V_{in}→V_{CF1}→V_{in}→V_{in}−V_{CF2} and VX2V_{X2} veries VinVCF2VinVinVCF1V_{in}→V_{CF2}→V_{in}→V_{in}−V_{CF1}.
waveform