The TPS63805 and TPS63806 are based on a peak-current mode architecture. The error amplifier provides a peak-current target (voltage that is translated into an equivalent current, see Figure 4), based on the current demand from the voltage loop. This target is compared to the actual inductor current during the ON-time. The ON-time is ended once the inductor current is equal to the current target and OFF-time is initiated. The OFF-time is calculated by the control and a function of VI and VO.