A High Efficiency Synchronous Rectification Step-up Dc-dc Converter Design

The power management is the hot-pot as the popularization of the consumer electronics, and becomes more important especially prominent in the portable electronics powered mainly by the battery. To adapt the market requirements, a high efficiency synchronous step up DC-DC converter was analyzed and designed in this thesis. The converter employs 0.5μm CMOS process, the typical efficiency reaches over 90% owing to the built-in synchronous rectifier, which can eliminate the need for an external Schottky diode, and so reduce the size and cost.The theory related to analyze the converter was introduced in the second chapter. Firstly, the top structure in the power stage was introduced, and on the basis, the basic principle and large signal behavior including the continuous current mode (CCM) and discontinuous current mode (DCM)were analyzed, the CCM small signal model of the SR(synchrounous recitfier) step up converter was obtained referring to the PWM model. Secondly, the synchronous principle and the related issue were analyzed. At last, the reliability of the power supply product was introduced and the method suiting in the design process, or the corner analysis was emphasized.During the circuit design, the whole chip structure was designed and the key points within the system design were emphasized to guarantee the design success. And then the sub-circuits in the charge of the author were designed in detail. In the reference design, the trimming technology was employed to adjust the process variation influencing on the reference voltage. In the current mirror, a resistor temperature compensation constant current mirror was designed.Finally, the whole chip and sub-circuits were simulated with the HSPICE in the process corners. It was showed that the results were in accordance with the design, which verified the design theory analyzed in the thesis. At present, the chip was taped out successfully.