| The paper is based on the project"synchronized Boost Converter"of the PAM(Shanghai) and mainly discusses the principle of the low current and synchronous Boost switching regulator.This paper analyzes and studies the basic principles of boost DC/DC converter which is the theory guidance of the design and the implementation of this system. This paper makes deep research and calculation to the system stability of boost DC/DC, and puts forwards a scheme of internal frequency compensation circuit. Then an internal frequency compensation circuit is designed and it can replace the external RC compensation network of the chip. And then I use the Verilog-AMS which based on Cadence Spectre to validate the stability of boost DC/DC, This scheme has very good reference meanings to other analog IC design. This system adopt peak current-mode control, the transient response speed of the supply voltage and the load's variety becomes more faster. Compensation circuit is designed in order to overcome the disadvantages of current mode control such as instability of open-loop. In this paper, a inside soft start circuit which could avoid the large current in course of starting is introduced. In addition, the IC introduces synchronous rectification technology to increase the efficiency and save the area of the PCB board. When the load became very small, the system will go the state of the skip-pulse in order to get more efficiency. Beside, lots of protection circuits are integrated in the chip, such as thermal shutdown, over voltage protection, under voltage lockout, over current protection, and so on.The whole circuit is designed based on the 0.6μm 40V BCD process. The simulation and verification is completed by the EDA tools such as spectre etc. According to the simulation results, the function and performance of the whole circuit have met all the requirements. |
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