When VI is close to VO, the TPS63805, TPS63806, and TPS63807 operate in buck-boost mode where all switches are active and the device repeats 3-cycles:
- TON: Boost-charge phase where boost low-side and buck high-side are closed and the inductor current is built up
- TOFF: Buck discharge phase where boost high-side and buck low-side are closed and the inductor is discharged
- TCOM: VI connected to VO where all high-side switches are closed and the input is connected to the output