Dc-dc Converters For Portable Applications And Implementation Of Xd1250

Motivated by emerging portable applications that demand ultra-low-power hardware to maximize battery run-time, high-efficiency low-voltage DC-DC conversion is presented as a key low-power enabler. Supported by the research item of institute of electronic CAD-"Theoretical research and design of key techniques for mixed ASIC", this thesis introduces and demonstrates an array of DC-DC converter design techniques, and a high-efficiency low-voltage Buck DC-DC converter for portable applications-XD1250 is designed.The primary design challenges to high-efficiency low-voltage DC-DC converters are summarized and the main loss sources are analyzed in detail. Then the thesis introduces and demonstrates an array of DC-DC converter design techniques which can help to meet the stringent requirements imposed by portable environment, including synchronous rectification, zero-voltage switching, adaptive dead-time control, dynamic power transistor sizing, reduced swing gate-drive, ultra-low-power PWM control and PWM-PFM control.A high efficiency DC-DC converter, XD1250, validates the design techniques. The reduced swing gate-drive technique, mode control technique and the synchronous control technique ensure high-efficiency with wide range of load current. XD1250 is available in the SOT-23 package, which is advanced in the power management IC market. Using Cadence and Hspice the circuit design, simulation and layout implementation of the chip are completed and then it's taped out abroad on a 0.5μm CMOS process. After a series of strict test with different load and temperature, XD1250 has been popularized to the market and got the satisfaction of the customers.