One Kind Of Ac / Dc Switching Power Supply Chip Control Circuit Design

This subject is supported by National Key Projects'Manufacturing Equipment and Complete Sets of Processes of VLSI'project,'Process Development and Industrialization of New Energy-saving Driver and Automotive Electronics Chip'subproject. The project is to design a monolithic AC / DC switching power supply IC. The IC integrates power devices and control circuits into one chip,which embraces over-temperature protection and over-current protection and uses current control mode and dynamic self-supply technology. Therefore, the chip has advantages of high integration, high reliability, low power consumption, simple peripheral circuits, low development cost and so on. In this paper, the feedback modulation system and the dynamic self-supply system of this chip is analyzed and designed in detail.Feedback modulation system designed in this paper uses PWM and PSM combined modulation method, which makes the system more stable, faster in reaction, stronger in anti-interference ability. Then, Current-Limit Comparer and Current-Limit State machine which are embraced in the system above are designed meticulously in this paper. SenseFET current-sensing technology is used in the Current-Limit Comparer, which reduce power consumption in ensuring the accuracy of current-sensingIn this paper, working principle of the dynamic self-supply system is elaborated in detail. Then, over&under-voltage detector and voltage regulator which are embraced in the system above are designed meticulously. The voltage regulator uses novel dynamic self-powered technology which reduces the system power consumption and the number of external components. Meanwhile, this method put forward higher requirements in the devices and circuits design, and adopts difficult trade-offs in the circuits design..The Hspice simulations prove that the design of that four blocks in the above can completely meets design requirements.