Design Of CMOS Multi-functional Leakage Current Protection Controller

With the rapid development of social and economic construction in china, electric network configuration becomes more and more huge and complicated correspondingly. People generally use leakage current protector in electric network. As a core part of leakage current protector, leakage current protection controller has a great influence on the performance of leakage current protector. Therefore, it becomes very important to research and design the leakage current protection controller.A multi-functional leakage current protection controller is presented in this paper. This controller is suitable for low-voltage distribution system. This controller has three main functions, and they are leakage current protection, overvoltage protection and overload protection. Circuit of internal digital delay design was used, improved on the old method which control circuit about delay used by RC delay circuit, and function to discriminate validity of input signals and function of multiple protection level selection was added. Meanwhile, switch which controls circuits and alarming circuits were designed. States and actions of switch were under complete controlled. CMOS Chrt0.35μm technique and mixing design method between digital and analog circuit were also used. We designed and made a simulation of this circuit using Cadence IC5141 and LDV software. We accomplished the bandgap references, the operational amplifiers and the logic operation circuits of every functional module in the multi-functional leakage current protection system, and made a simulation. The results showed that functions of each functional module can be realized. Meanwhile, we made a simulation all of the logic operation circuits, the results also showed that the functions can be realized. Finally the layout of some circuits is presented.