A wide input voltage range DC-DC Buck converter with dynamically modified ZCD circuit

Abstract

This article proposes a wide input voltage range DC-DC buck converter based on AOT control mode, which can be used in low-power applications such as the Internet of Things and automotive chips. It includes a zero current detector circuit that dynamically modifies the offset voltage, which can detect the inductor current when the buck circuit is operating in DCM mode. By turning off the power transistor in time, the control loss of the buck circuit can be reduced to improve efficiency. The proposed buck converter is designed using 0.18µm standard CMOS process. When a 12V standard input voltage is used to generate a 5V output voltage, the minimum inductor current can reach about 100uA when the low power transistor is turned off when the load current is in the light load range of 1mA-100mA, and the maximum efficiency can be achieved at light load of 93.7%.