Design and Control of An Integrated 3-Level Boost Converter under DCM Operation

A 3-level boost (3LB) converter has the characteristics of higher voltage conversion efficiency, lower inductor current ripples, output voltage ripples and voltage stresses on switches when compared with the conventional boost converters in continuous conduction mode (CCM). When the 3LB is integrated on a chip, we cannot avoid its discontinuous conduction mode (DCM) operation due to a small inductance and load variation. In this paper we'll present and discuss the design and control of a 3LB converter in DCM operation, implemented in a 65-nm CMOS process. Transistor level simulation results show that it operates at 100 MHz with a 5nH inductor, a 4nF output capacitor and a 2.5nF fly capacitor achieving an output conversion range of 1.5 V to 2.1V from a 1.2 V input supply, with a peak efficiency of 83.2%@90mW, a load transient response of 141mV and 1.64ns/mA for undershoot, 136mV and 1.93ns/mA for overshoot, and a voltage ripple less than 60/85mV when ILoad =40/80mA with a typical and the maximum output voltage ripple of less than 90mV in the worst corner.