Design of an output stage for high switching frequency DC-DC converters

We present an output stage design for high switching frequency DC-DC converters. The output stage comprises level-shifters, gate drivers, and power transistors. Gate drivers designed with the low voltage-swing method are evaluated against the standard full voltage-swing. Based on the simulation results, the gate drivers with the full voltage-swing results in higher power-efficiency and correspondingly, is employed in the output stage design. The output stage is designed using a 0.18 μm CMOS technology. The input pulse voltage to the output stage is 1.8 V and is level-shifted up to 3.3 V for a broad operational range of 0 to 3.3 V DC-DC conversions in portable applications. Simulation results show that at a switching frequency of 5 MHz and an output voltage of 1.65 V (50 % pulse duty cycle), the output stage delivers 300 mA current at a power efficiency of 89 %.