Reduction of equivalent series inductor effect in constant on- time control DC-DC converter without ESR compensation

The proposed constant on-time control DC-DC converter removes the need of conventional equivalent series resistor (ESR) compensation and simultaneously aims to eliminate equivalent series inductor (ESL) effect of the output capacitor. Since the on-time period is set simply by input and output voltages, the switching frequency in continuous conduction mode (CCM) operation is relatively constant over a wide input voltage range. In addition, fast transient response and small transient dip voltage can be achieved. Simulation results show that the output ripple and the recovery time keep smaller than 5 mV and 10 μs, respectively, when load current step is 500 mA and ESR is smaller than 5 mΩ.