Constant on-time controlled four-phase buck converter via two ways of saw-tooth-wave circuit and PLL circuit

This paper proposes a four-phase buck converter with constant on-time control, which can provide large output current with low voltage ripple. We describe here two methods, which are saw-tooth-wave and PLL circuits, to achieve the four-phase converter. As a result, both methods well achieved the four-phase control, showing stable current balance and better transient response compared to single-phase converter. As for capacity of large load current, the saw-tooth-wave method achieves high current level with stable current balance, and behaves better than the PLL method.