A low-voltage CMOS DC-DC converter for a portable battery-operated system

Motivated by emerging battery-operated applications that demand compact, lightweight, and highly efficient DC-DC power converters, a buck circuit is presented in which all active devices are integrated on a single chip using a standard 1.2 μ CMOS process. The circuit delivers 750 mW at 1.5 V from a 6 V battery. To effectively eliminate switching loss at high operating frequencies, the power transistors achieve nearly ideal zero-voltage switching (ZVS) through an adjustable dead-time control scheme. The silicon area and power consumption of the gate-drive buffers are reduced with a tapering factor that minimizes short-circuit current and dynamic dissipation for a given technology and application. Measured results on a prototype IC indicate that on-chip losses at full load can be kept below 8% at 1 MHz