| A 1.2MHz high-voltage peak current-mode non-synchronous Buck DC-DC converter XD2010 is designed on the basis of the project"Theoretical Research and Design of Key Techniques for Deep-submicron Power Management IC and Mixed IC".Firstly, the basic structure and operational principle of Buck DC-DC converter are discussed. Then the system of XD2010 is designed and the electrical characteristics are also introduced. Meanwhile, the key techniques of the design are researched, including the choice of the process, the self-biased reference current source ofβtimes and stability analysis of the loop. Afterward, the design and simulation of key sub-circuits are presented. Finally, the simulation waves of the whole chip are given.The frequency of XD2010 is 1.2MHz and a novel internal compensation technique is proposed. Compared with the traditional off-chip compensation structure, this method can not only achieve high loop stability, but also simplify the design and reduce the pins of chip, which can save the PCB space. The internal current reference makes the operation frequency irrevalent with the supply voltage and the temperature. Also, the peak current pulse width modulation is chosen for the loop control of XD2010, which makes the transient responses to the supply voltage and the load current of the chip become much faster. The supply voltage of the chip can rise as high as 30V by using the DMOS transistors. Moreover, the precise inductor sensing current is obtained by detecting the voltage across the drain and source of the main power transistor. The protection circuits, such as short protection, thermal shutdown, overcurrent protection, undervoltage lockout, are integrated in the chip, making the operation of the chip more secure and stable.The design and simulation of XD2010 are completed by using Cadence and Hspice software based on the 0.6μm CDMOS process. The simulation results show that the performance in application is excellent and can meet the prospective specifications. |
